Commitments and Contingencies Minimum Aggregate Future Obligations Under Non-cancelable Leases (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Commitments and Contingencies Disclosure [Abstract]
2014	$ 31,583,000
2015	31,502,000
2016	28,924,000
2017	28,275,000
2018	24,331,000
Thereafter	47,715,000
Total	192,330,000
Rent expense	30,800,000	23,500,000	23,000,000
Proceeds from sublease tenants	$ 1,900,000	$ 1,400,000	$ 800,000