Commitments (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Commitments [Abstract]
Total net rent expense	$ 10,100,000	$ 13,300,000	$ 10,100,000
Net Operating Leases
2012	15,927,000
2013	7,856,000
2014	5,699,000
2015	1,949,000
2016	896,000
Thereafter	174,000
Total minimum payments	32,501,000
Other Contractual Obligations
2012	3,278,000
2013	575,000
2014	550,000
2015	550,000
2016	550,000
Thereafter	275,000
Total minimum payments	$ 5,778,000