Commitments and Contingencies Lease Commitments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Future Minimum Payments Due, Less than 1 year	$ 1,939
Operating Leases, Future Minimum Payments, 1 year to 3 years	1,296
Operating Leases, Future Minimum Payments, 3 years to 5 years	30
Operating Leases, Future Minimum Payments, More than 5 years	0
Operating Leases, Future Minimum Payments Due	3,265
Operating Leases, Rent Expense, Net	$ 1,900	$ 1,100	$ 600