Consolidated Statements of Cash Flows (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents [Abstract]
Cash and cash equivalents - unrestricted	$ 103,437	$ 57,557	$ 59,128
Cash and cash equivalents - restricted	45,652	21,153	22,062
Cash, cash equivalents, and restricted cash, end of period	$ 149,089	$ 78,710	$ 81,190	$ 78,646