Income Taxes - Unrecognized Tax Benefit (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Unrecognized Tax Benefits [Roll Forward]
Gross unrecognized tax benefits at beginning of year	$ 21,240	$ 20,010	$ 27,910
Increases in tax positions for prior years	623	1,500	400
Decreases in tax positions for prior years	(1,287)	(270)	(15,900)
Increases in tax positions for current year	0	0	8,400
Decreases from lapse in statute of limitations	(4,190)	0	0
Settlements	0	0	(800)
Gross unrecognized tax benefits at end of year	$ 16,386	$ 21,240	$ 20,010