Commitments and Contingencies - Minimum Aggregate Future Obligations Under Non-cancelable Leases and Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
2016	$ 52,456,000
2017	51,978,000
2018	43,683,000
2019	39,800,000
2020	19,487,000
Thereafter	72,117,000
Total	279,521,000
Rent expense	47,900,000	$ 39,900,000	$ 30,800,000
Proceeds from sublease tenants	3,600,000	$ 3,400,000	$ 1,900,000
Letters of credit for real estate leases	$ 6,000,000
Percentage revenue representation for investigation of sales practices (less than 1%)	1.00%	1.00%	1.00%
Provision for sales practice internal investigation	$ 0