Commitments and Contingencies Contract Settlement (Details) - USD ($) $ in Thousands	3 Months Ended			6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Commitments and Contingencies Disclosure [Abstract]
contract settlement	$ 1,039	$ 12,700	$ 0	$ 3,822	$ 28,917