CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS CONDENSED CONSOLIDATED STATEMENT OF CASH FLOW (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Cash and cash equivalents	$ 584,081	$ 582,585
Restricted cash	1,195	270
Cash, cash equivalents, restricted cash and restricted cash equivalents	585,276	582,855
Prepaid and other current assets
Restricted cash	0	91
Other noncurrent assets
Restricted cash	$ 1,195	$ 179