Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Leases [Abstract]
Rental expense	$ 13,800,000	$ 14,000,000	$ 14,000,000
Operating leases minimum payments due [Abstract]
2013	13,648,000
2014	10,658,000
2015	7,068,000
2016	5,196,000
2017	3,258,000
Thereafter	2,481,000
Total minimum lease payments	$ 42,309,000