Supplemental Cash Flow Information - Reconciliation of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019	Dec. 31, 2018
Cash, Cash Equivalents and Restricted Cash [Line Items]
Cash and cash equivalents	$ 377,205	$ 164,798	$ 85,423	$ 78,687
Total cash, cash equivalents, and restricted cash reported in the statements of cash flows	381,638	169,745	89,492	83,256
Prepaid Expenses and Other Current Assets
Cash, Cash Equivalents and Restricted Cash [Line Items]
Restricted cash and cash equivalents	3,514	4,026	3,038	3,286
Other Assets
Cash, Cash Equivalents and Restricted Cash [Line Items]
Restricted cash and cash equivalents	$ 919	$ 921	$ 1,031	$ 1,283