Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Income Taxes
Balance at beginning of year	$ 24,538	$ 23,052	$ 20,734
Additions (subtractions) based on tax positions related to prior year	(1,388)	755	1,634
Additions based on tax positions related to current year	474	731	684
Balance at end of year	23,624	24,538	23,052
Unrecognized tax benefits that would affect the effective tax rate if recognized	$ 13,300	$ 13,200	$ 9,800