Organization and Basis of Presentation - Cash, Cash Equivalents and Restricted Cash And Cash Equivalents (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Cash and cash equivalents-unrestricted	$ 107,034	$ 134,465	$ 121,954	$ 44,620
Cash and cash equivalents-restricted	17,092	16,930	17,124	16,506
Total unrestricted and restricted cash and cash equivalents shown in the condensed consolidated statement of cash flows	$ 124,126	$ 151,395	$ 139,078	$ 61,126