Basis of Presentation and Summary of Significant Accounting Policies - Impact of New Accounting Standard on Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Assets
Prepaid expenses and other current assets	$ 165,628	$ 151,102
Other assets	286,391	247,519
Liabilities
Deferred tax liabilities	1,060,900	1,166,269
Stockholders' equity
Accumulated deficit	$ (3,072,852)	$ (2,742,193)