Basis of Condensed Consolidated Financial Statements (Cash, Cash Equivalents and Restricted Cash) (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	$ 86,828	$ 85,271	$ 123,698
Restricted cash included in other assets	11,134		9,806
Restricted cash included in prepaid expenses and other current assets	1,985		1,069
Total cash, cash equivalents and restricted cash	$ 99,947	$ 98,250	$ 134,573	$ 132,154