Income Taxes (Details 4) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Reconciliation of the unrecognized tax benefits
Balance at beginning of year	$ 3,329	$ 2,924	$ 2,685
Additions for tax positions of prior years	366	277	239
Additions for tax positions of current year		128
Reductions for tax positions of prior years	(48)
Balance at end of year	$ 3,647	$ 3,329	$ 2,924