Income Taxes - Components of the Provision for Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Current:
Federal	$ 32,656	$ 1,866	$ 258
State and local	3,250	74	68
Foreign	963	263	189
Total current expense	36,869	2,203	515
Deferred:
Federal	27,870	42,148	(48,934)
State and local	1,385	2,032	(3,877)
Total deferred expense (benefit)	29,255	44,180	(52,811)
Total income tax expense (benefit)	$ 66,124	$ 46,383	$ (52,296)