Income Taxes - Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Unrecognized tax benefits [Roll Forward]
Balance at beginning of period	$ 18,326	$ 18,507
Additions for tax positions related to the current year	0	0
Additions (reductions) for tax positions related to prior years	59
Additions (reductions) for tax positions related to prior years		(181)
Balance at end of period	$ 18,385	$ 18,326