Income Taxes - Reconciliation of Uncertain Tax Positions (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 the beginning of the year	$ 10,560	$ 13,020	$ 12,695
Additions based on tax positions related to the current year	12	574	300
Additions for tax positions from prior years	608	340	69
Subtractions for federal tax reform	0	(3,296)	0
Subtractions for tax positions from prior years	0	(78)	(44)
Unrecognized tax benefits at the end of the year	$ 11,180	$ 10,560	$ 13,020