Segment Reporting (Details) (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013 segment	Sep. 30, 2012	Dec. 31, 2012
Segment Reporting
Number of operating segments			4
Segment Reporting information
Total revenues	$ 127,558,000	$ 119,617,000	$ 398,901,000	$ 382,902,000
Income (loss) before income tax expense (benefit)	10,690,000	181,000	32,412,000	(261,885,000)
Identifiable assets	3,157,310,000	2,384,596,000	3,157,310,000	2,384,596,000	2,196,759,000
Impairment charges on goodwill included in loss before income tax benefits				274,285,000
U.S. Operations
Segment Reporting information
Total revenues	76,843,000	77,801,000	242,687,000	244,305,000
Income (loss) before income tax expense (benefit)	4,478,000	841,000	14,779,000	(239,715,000)
Identifiable assets	1,377,616,000	1,101,085,000	1,377,616,000	1,101,085,000
Duplicate rent charges			2,600,000
One-time charge upon completion of the move			3,900,000
Impairment charges on goodwill included in loss before income tax benefits				245,100,000
U.S. Operations | Restructuring accruals recorded in 2012 and 2011
Segment Reporting information
Reduction in previously recorded restructuring accruals	1,300,000
Canadian Operations
Segment Reporting information
Total revenues	17,575,000	17,727,000	56,224,000	58,877,000
Income (loss) before income tax expense (benefit)	2,749,000	1,637,000	9,120,000	9,020,000
Identifiable assets	137,389,000	98,082,000	137,389,000	98,082,000
Canadian Operations | Restructuring accruals recorded in 2012 and 2011
Segment Reporting information
Reduction in previously recorded restructuring accruals	300,000
European Operations
Segment Reporting information
Total revenues	22,663,000	14,793,000	65,407,000	50,412,000
Income (loss) before income tax expense (benefit)	4,115,000	(286,000)	10,436,000	(25,524,000)
Identifiable assets	1,128,133,000	567,527,000	1,128,133,000	567,527,000
Facility closing expense			1,600,000
Impairment charges on goodwill included in loss before income tax benefits				28,500,000
Asia Pacific Operations
Segment Reporting information
Total revenues	10,477,000	9,296,000	34,583,000	29,308,000
Income (loss) before income tax expense (benefit)	(652,000)	(2,011,000)	(1,923,000)	(5,666,000)
Identifiable assets	514,172,000	617,902,000	514,172,000	617,902,000
Impairment charges on goodwill included in loss before income tax benefits				$ 700,000