Income Taxes - Changes in Unrecognized Tax Benefits (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax Disclosure [Abstract]
Balance as of January 1	$ 861	$ 1,465	$ 726
Increases (decreases) in unrecognized tax benefits:
Due to tax positions taken in prior years	0	91	729
Due to tax positions taken during the current year	45	60	44
Due to settlement with tax authorities	(757)	0	(34)
Due to expiration of statute	(44)	(755)	0
Balance as of December 31	$ 105	$ 861	$ 1,465