Douglas Dynamics, Inc. Annual report pursuant to Section 13 and 15(d)

Employee Retirement Plans - Asset Allocation (Details)

Employee Retirement Plans - Asset Allocation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee retirement plans
Actual allocation of pension plan assets	$ 33,903	$ 29,223
Pension plan
Employee retirement plans
Actual allocation of pension plan assets	$ 33,903	29,223	$ 26,378
Qualified Hourly Pension Plan [Member]
Employee retirement plans
Target (as a percent)	100.00%
Actual allocation of pension plan assets	$ 6,438	$ 5,576
Weighted-average asset allocation (as a percent)	100.00%	100.00%
Qualified Hourly Pension Plan [Member] \| Large Cap Equity
Employee retirement plans
Target (as a percent)	34.00%
Actual allocation of pension plan assets	$ 2,259	$ 1,991
Weighted-average asset allocation (as a percent)	35.00%	36.00%
Qualified Hourly Pension Plan [Member] \| Mid Cap Equity
Employee retirement plans
Target (as a percent)	3.00%
Actual allocation of pension plan assets	$ 199	$ 177
Weighted-average asset allocation (as a percent)	3.00%	3.00%
Qualified Hourly Pension Plan [Member] \| Small Cap Equity
Employee retirement plans
Target (as a percent)	1.00%
Actual allocation of pension plan assets	$ 73	$ 67
Weighted-average asset allocation (as a percent)	1.00%	1.00%
Qualified Hourly Pension Plan [Member] \| International Equity
Employee retirement plans
Target (as a percent)	14.00%
Actual allocation of pension plan assets	$ 950	$ 664
Weighted-average asset allocation (as a percent)	15.00%	12.00%
Qualified Hourly Pension Plan [Member] \| Emerging markets Equity
Employee retirement plans
Target (as a percent)	2.00%
Actual allocation of pension plan assets	$ 128	$ 88
Weighted-average asset allocation (as a percent)	2.00%	2.00%
Qualified Hourly Pension Plan [Member] \| Fixed Income and Cash Equivalents
Employee retirement plans
Target (as a percent)	40.00%
Actual allocation of pension plan assets	$ 2,447	$ 2,256
Weighted-average asset allocation (as a percent)	38.00%	40.00%
Qualified Hourly Pension Plan [Member] \| Real Estate
Employee retirement plans
Target (as a percent)	6.00%
Actual allocation of pension plan assets	$ 382	$ 333
Weighted-average asset allocation (as a percent)	6.00%	6.00%
Salaried Pension Plan
Employee retirement plans
Target (as a percent)	100.00%
Actual allocation of pension plan assets	$ 27,465	$ 23,647
Weighted-average asset allocation (as a percent)	100.00%	100.00%
Salaried Pension Plan \| Large Cap Equity
Employee retirement plans
Target (as a percent)	21.00%
Actual allocation of pension plan assets	$ 6,111	$ 8,444
Weighted-average asset allocation (as a percent)	23.00%	36.00%
Salaried Pension Plan \| Mid Cap Equity
Employee retirement plans
Target (as a percent)	2.00%
Actual allocation of pension plan assets	$ 542	$ 752
Weighted-average asset allocation (as a percent)	2.00%	3.00%
Salaried Pension Plan \| Small Cap Equity
Employee retirement plans
Target (as a percent)	1.00%
Actual allocation of pension plan assets	$ 201	$ 282
Weighted-average asset allocation (as a percent)	1.00%	1.00%
Salaried Pension Plan \| International Equity
Employee retirement plans
Target (as a percent)	9.00%
Actual allocation of pension plan assets	$ 2,573	$ 2,815
Weighted-average asset allocation (as a percent)	9.00%	12.00%
Salaried Pension Plan \| Emerging markets Equity
Employee retirement plans
Target (as a percent)	1.00%
Actual allocation of pension plan assets	$ 348	$ 374
Weighted-average asset allocation (as a percent)	1.00%	2.00%
Salaried Pension Plan \| Fixed Income and Cash Equivalents
Employee retirement plans
Target (as a percent)	60.00%
Actual allocation of pension plan assets	$ 16,046	$ 9,565
Weighted-average asset allocation (as a percent)	58.00%	40.00%
Salaried Pension Plan \| Real Estate
Employee retirement plans
Target (as a percent)	6.00%
Actual allocation of pension plan assets	$ 1,644	$ 1,415
Weighted-average asset allocation (as a percent)	6.00%	6.00%