Income Taxes - Reconciliation of Unrecognized Tax Benefits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Reconciliation of unrecognized tax benefits:
Gross tax contingencies - beginning of the period	$ 35,320	$ 38,533	$ 59,466
Gross additions based on tax positions related to the current year	2,914	3,147	4,067
Gross additions for tax positions of prior years	1,271	981	3,368
Gross reductions for tax positions of prior years	(299)	(2,865)	(2,789)
Lapses of statutes	(4,034)	(4,462)	(2,629)
Settlements	(104)	(14)	(22,950)
Gross tax contingencies - end of the period	$ 35,068	$ 35,320	$ 38,533