Operating Segments and Related Information (Details 4) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue	$ 386,385	$ 332,230	$ 338,291	$ 348,452	$ 405,212	$ 371,327	$ 391,554	$ 375,969	$ 1,405,358	$ 1,544,062	$ 1,388,437
United States
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									717,841	803,423	734,748
Europe
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									337,163	382,388	318,321
Other foreign
Segment Reporting, Revenue Reconciling Item [Line Items]
Revenue									$ 350,354	$ 358,251	$ 335,368