Segment Reporting - Financial Information (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($) segment	Mar. 31, 2015 USD ($)	Dec. 31, 2015 USD ($)
Segment reporting
Number of operating segments | segment	4
Total Revenues	$ 124,668	$ 149,727
Income (loss) before income tax expense	(3,638)	22,340
Identifiable assets	1,617,223	1,529,451	$ 1,709,022
Reserve for probable settlement with SEC	2,500
Legal and related costs	300
U.S. Operations
Segment reporting
Total Revenues	66,329	80,454
Income (loss) before income tax expense	2,105	11,056
Identifiable assets	1,196,340	1,098,740
Canadian Operations
Segment reporting
Total Revenues	16,096	18,913
Income (loss) before income tax expense	3,338	3,756
Identifiable assets	100,599	78,782
European Operations
Segment reporting
Total Revenues	31,139	36,605
Income (loss) before income tax expense	5,679	11,129
Identifiable assets	253,135	281,637
Asia Pacific Operations
Segment reporting
Total Revenues	10,757	13,522
Income (loss) before income tax expense	(600)	1,107
Identifiable assets	67,149	70,292
Corporate
Segment reporting
Total Revenues	347	233
Income (loss) before income tax expense	$ (14,160)	$ (4,708)