Supplemental Disclosure of Cash Flow Information - Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 256,501	$ 398,267
Restricted cash	28,811	27,683
Long-term restricted cash	43,188	24,268
Total cash, cash equivalents and restricted cash shown in the condensed consolidated statement of cash flows	$ 328,500	$ 450,218	$ 395,561	$ 282,546