Borrowings (Details) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 16, 2016	Jun. 15, 2016
Borrowings
Fixed charge coverage ratio	110.00%
Wells Fargo Bank, N.A. | ABL Facility
Borrowings
Maximum borrowing capacity	$ 54,000,000	$ 54,000,000	$ 60,000,000
Current borrowing base	46,900,000
Amount outstanding	40,700,000
Maximum amount available for borrowing for initial 12-month fixed charge coverage ratio	$ 15,000,000
Maximum percent available for borrowing for initial 12-month fixed charge coverage ratio (percent)	25.00%
Minimum amount available for borrowing for continuing compliance with 12-month fixed charge coverage ratio	$ 15,000,000
Minimum percent available for borrowing for continuing compliance with 12-month fixed charge coverage ratio (percent)	25.00%
Continuing compliance requirement for 12-month fixed charge coverage ratio (days)	30 days
Minimum amount of excess availability for trigger date to occur	$ 10,000,000
Percent of commitments for trigger date to occur (percent)	16.67%
Percent of commitments for trigger date to occur, continuing compliance (percent)	16.67%
Continued dominion period	30 days
U.S.
Borrowings
Foreign borrowings that were subject to the bank's dominion	$ 37,200,000
Foreign Locations
Borrowings
Foreign borrowings that were subject to the bank's dominion	$ 3,500,000