Supplemental Disclosure of Cash Flow Information - Cash and Restricted Cash (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Cash and cash equivalents	$ 398,267	$ 222,647
Restricted cash	27,683	37,189
Long-term restricted cash	24,268	22,710
Total cash, cash equivalents and restricted cash shown in the consolidated statement of cash flows	$ 450,218	$ 282,546	$ 277,322	$ 153,981