Segment Reporting (Details 4) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total plant, equipment and leasehold improvement additions	$ 4,198	$ 5,806	$ 14,588	$ 12,384
Total long-lived assets	178,375		178,375		$ 177,276
U.S.
Segment Reporting Information [Line Items]
Total plant, equipment and leasehold improvement additions	3,625	5,705	13,598	12,000
Total long-lived assets	162,854		162,854		160,144
Canada
Segment Reporting Information [Line Items]
Total plant, equipment and leasehold improvement additions	136	3	417	25
Total long-lived assets	2,382		2,382		2,525
Total North America
Segment Reporting Information [Line Items]
Total plant, equipment and leasehold improvement additions	3,761	5,708	14,015	12,025
Total long-lived assets	165,236		165,236		162,669
U.K.
Segment Reporting Information [Line Items]
Total plant, equipment and leasehold improvement additions	437	$ 98	573	$ 359
Total long-lived assets	$ 13,139		$ 13,139		$ 14,607