Income Taxes Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Unrecognized tax benefits at beginning of the year	$ 1,525	$ 1,525	$ 1,525
Reversal of prior year unrecognized tax benefits due to the expiration of the statute of limitations	(878)	0	0
Unrecognized tax benefits at end of the year	$ 647	$ 1,525	$ 1,525