Commitments, Contingencies and Guarantees (Minimum Aggregate Future Obligations Under Non-cancelable Leases) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Commitments Contingencies and Guarantees [Abstract]
2013	$ 33,208,000
2014	30,699,000
2015	28,140,000
2016	17,478,000
2017	15,918,000
Thereafter	29,674,000
Total	155,117,000
Rent expense	23,500,000	23,000,000	23,600,000
Proceeds from sublease tennants	$ 1,400,000	$ 800,000	$ 3,300,000