Supplemental Cash Flow Information - Schedule of Cash, Cash Equivalents and 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	$ 124,990	$ 110,790	$ 78,864
Restricted cash	30,114	29,056	29,877
Cash, cash equivalents and restricted cash	$ 155,104	$ 139,846	$ 108,741	$ 82,203