Income Taxes - Provision for Income Taxes (Details) (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
Current taxes:
U.S. federal									$ 34,752	$ 13,419	$ 15,803
State and local									4,747	2,848	(83)
Foreign									7,116	13,357	6,795
Total current tax expense									46,615	29,624	22,515
Deferred taxes:
U.S. federal									(15,119)	(7,501)	(1,226)
State and local									(796)	(617)	941
Foreign									(2,317)	2,580	(2,700)
Total deferred tax (benefit) expense									(18,232)	(5,538)	(2,985)
Total tax expense	$ 13,000	$ 5,300	$ 1,300	$ 8,700	$ 9,000	$ 4,400	$ 11,600	$ (1,000)	$ 28,383	$ 24,086	$ 19,530