Commitments and Contingencies - Minimum Aggregate Future Obligations Under Non-cancelable Leases and Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
2018	$ 50,187
2019	49,418
2020	61,031
2021	58,680
2022	56,211
Thereafter	481,471
Total	756,998
Rent expense	58,800	$ 50,300	$ 47,900
Proceeds from sublease tenants	3,600	$ 1,300	$ 3,600
Letters of credit for real estate leases	$ 6,400