Valuation and Qualifying Accounts (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Allowance for doubtful accounts
Activity in valuation and qualifying accounts
Balance at beginning of period	$ 162	$ 162	$ 175
Charged to costs and expenses		134	12
Other charges	(2)	(134)	(25)
Balance at end of period	160	162	162
Deferred tax assets valuation allowance
Activity in valuation and qualifying accounts
Balance at beginning of period	1,036	1,688	30
Charged to costs and expenses	(59)	(652)	1,667
Other charges			(9)
Balance at end of period	$ 977	$ 1,036	$ 1,688