Borrowings (Details)	3 Months Ended
	Mar. 31, 2016 USD ($)
Borrowings
Fixed charge coverage ratio	110.00%
Foreign borrowings that were subject to the bank's dominion	$ 4,500,000
Wells Fargo Bank, N.A. | ABL Facility
Borrowings
Maximum borrowing capacity	60,000,000
Current borrowing base	54,200,000
Amount outstanding	$ 39,500,000
Maximum percent available for borrowing for initial 12-month fixed charge coverage ratio (percent)	25.00%
Maximum amount available for borrowing for initial 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%
Minimum amount available for borrowing for continuing compliance with 12-month fixed charge coverage ratio	$ 15,000,000
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%