Commitments (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments [Abstract]
Total net rent expense	$ 13,600,000	$ 10,100,000	$ 13,300,000
Net Operating Leases
2013	12,051,000
2014	8,967,000
2015	4,710,000
2016	3,381,000
2017	2,344,000
Thereafter	5,625,000
Total minimum payments	37,078,000
Other Contractual Obligations
2013	3,889,000
2014	1,291,000
2015	1,040,000
2016	550,000
2017	275,000
Thereafter	0
Total minimum payments	$ 7,045,000