Income Taxes - Unrecognized Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at January 1	$ 12,636	$ 9,842
Increases related to prior year tax positions	712	4,431
Decreases related to prior year tax positions	(181)	(162)
Increases related to current year tax positions	180	3,297
Settlements	0	(4,442)
Reduction due to lapse of applicable statute of limitations	(169)	(330)
Balance at December 31	$ 13,178	$ 12,636