Summary of Significant Accounting Policies - Newly-Adopted Accounting Pronouncements (Details) - USD ($) $ in Thousands	Jan. 01, 2019	Dec. 31, 2019	Dec. 31, 2018
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets		$ 758,450
Deferred rent		$ 0	$ 42,566
Income tax expense (benefit)	$ 900
Lease ASU
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Operating lease right-of-use assets	362,200
Total lease liabilities	394,100
Deferred rent	$ 31,700