Quarterly report pursuant to Section 13 or 15(d)

Employee Stock Plans - Additional Information (Details)

v3.5.0.2
Employee Stock Plans - Additional Information (Details)
 3 Months Ended 6 Months Ended
Jun. 30, 2016
USD ($)
age
shares
Mar. 31, 2016
USD ($)
Jun. 30, 2015
USD ($)
Mar. 31, 2015
USD ($)
Jun. 30, 2016
USD ($)
Jun. 30, 2015
USD ($)
Restricted Stock Share Awards            
Additional Employee Stock Plans Informatioin            
Compensation expenses recognized $ 0   $ 107,000   $ 0.000 $ 272,000.000
Performance Share Unit Awards            
Additional Employee Stock Plans Informatioin            
Compensation expenses recognized         506,000 529,000
Performance Share Unit Awards | 2010 Plan            
Additional Employee Stock Plans Informatioin            
Vesting period of awards 2 years          
Compensation expenses recognized $ 380,000   402,000      
Unrecognized compensation expense, net of expected forfeitures, calculated under the fair value method for shares expected to vest 1,050,000       1,050,000  
Restricted Stock Unit Awards            
Additional Employee Stock Plans Informatioin            
Compensation expenses recognized 143,000   $ 348,000   1,230,000 $ 1,180,000
Unrecognized compensation expense, net of expected forfeitures, calculated under the fair value method for shares expected to vest $ 740,000       $ 740,000  
Restricted Stock Unit Awards | Non-employee director            
Additional Employee Stock Plans Informatioin            
Number of shares issued upon exercise of units other than options | shares 1          
Restricted Stock Unit Awards | Management            
Additional Employee Stock Plans Informatioin            
Minimum age of employee, attaining which awards are continued to be vested upon retirement | age 65          
Minimum service period, upon serving which awards are continued to be vested upon retirement 10 years          
Minimum age of employee along with service period condition, attaining which awards are continued to be vested upon retirement | age 55          
Accelerated stock based compensation expense   $ 528,000   $ 303,000    
Restricted Stock Unit Awards | Common Stock | Management            
Additional Employee Stock Plans Informatioin            
Number of shares issued upon exercise of units other than options | shares 1          
Restricted Stock Unit Awards | 2010 Plan            
Additional Employee Stock Plans Informatioin            
Maximum period following a termination of service in which the share-based award will be settled 2 months 15 days