Supplemental Disclosures of Cash Flow Information and Non-Cash Financing and Investing Activities - Schedule of Reconciliation of Cash and Cash Equivalents Inclusive of Restricted Cash (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 497,510	$ 438,961	$ 422,971	$ 573,383
Restricted cash	377,085	338,635	301,716	250,705
Total cash and cash equivalents inclusive of restricted cash at the end of the period	$ 874,595	$ 777,596	$ 724,687	$ 824,088