Income Taxes - Unrecognized Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of period	$ 1,192	$ 1,234	$ 810
Gross increases to current period tax positions	0	59	180
Gross (decreases) increases to prior period tax positions	(848)	(101)	244
Unrecognized tax benefits at end of period	$ 344	$ 1,192	$ 1,234