Annual report pursuant to Section 13 and 15(d)

Description of business and basis of presentation (Details)

v3.3.1.900
Description of business and basis of presentation (Details) - USD ($)
$ in Thousands
Dec. 31, 2015
Feb. 20, 2015
Dec. 31, 2014
Interest rate swap      
Interim Consolidated Financial Information      
Fixed interest rate (as a percent)     6.335%
Interest rate swap | London Interbank Offered Rate (LIBOR) [Member]      
Interim Consolidated Financial Information      
Interest rate added to variable rate (as a percent)     4.25%
LIBOR floor (as a percent)     1.50%
Interest Rate Swap Effective 31 December 2015 through 29 March 2018 [Member]      
Interim Consolidated Financial Information      
Notional amount   $ 90,000  
Fixed interest rate (as a percent) 6.916%    
Interest Rate Swap Effective 31 December 2015 through 29 March 2018 [Member] | London Interbank Offered Rate (LIBOR) [Member]      
Interim Consolidated Financial Information      
Interest rate added to variable rate (as a percent) 4.25%    
LIBOR floor (as a percent) 1.00%    
Interest Rate Swap Effective 29 March 2018 through 31 March 2020 [Member]      
Interim Consolidated Financial Information      
Notional amount   45,000  
Fixed interest rate (as a percent) 6.105%    
Interest Rate Swap Effective 29 March 2018 through 31 March 2020 [Member] | London Interbank Offered Rate (LIBOR) [Member]      
Interim Consolidated Financial Information      
Interest rate added to variable rate (as a percent) 4.25%    
LIBOR floor (as a percent) 1.00%    
Interest Rate Swap Effective 31 March 2020 through 30 June 2021 [Member]      
Interim Consolidated Financial Information      
Notional amount   $ 135,000  
Fixed interest rate (as a percent) 7.168%    
Interest Rate Swap Effective 31 March 2020 through 30 June 2021 [Member] | London Interbank Offered Rate (LIBOR) [Member]      
Interim Consolidated Financial Information      
Interest rate added to variable rate (as a percent) 4.25%    
LIBOR floor (as a percent) 1.00%