Supplemental Cash Flow Information - Schedule of Cash, Cash Equivalents 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	$ 120,117	$ 110,790	$ 86,021
Restricted cash	26,535	29,056	31,947
Cash, cash equivalents and restricted cash	$ 146,652	$ 139,846	$ 117,968	$ 82,203