Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of unrecognized tax benefits:
Gross tax contingencies - beginning of the period	$ 35,068	$ 35,320	$ 38,533
Gross additions based on tax positions related to the current year	2,907	2,914	3,147
Gross additions for tax positions of prior years	80	1,271	981
Gross reductions for tax positions of prior years	(5,617)	(299)	(2,865)
Lapses of statutes	(4,480)	(4,034)	(4,462)
Settlements	(1,989)	(104)	(14)
Gross tax contingencies - end of the period	$ 25,969	$ 35,068	$ 35,320