Income Taxes - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Taxes
Balance at beginning of year	$ 23,052	$ 20,734	$ 3,892
Additions (subtractions) based on tax positions related to prior year	755	1,634	16,103
Additions based on tax positions related to current year	731	684	739
Balance at end of year	24,538	23,052	20,734
Unrecognized tax benefits that would affect the effective tax rate if recognized	$ 13,200	$ 9,800	$ 8,600