Income Taxes - Unrecognized Tax Benefits Reconciliation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Unrecognized Tax Benefits Reconciliation
Balance at beginning of year	$ 35,879	$ 24,361	$ 31,534
Additions based on tax positions taken during a prior period	13,018	583	2,342
Reductions based on tax positions taken during a prior period	(86)	(1,248)	(1,242)
Additions related to positions taken upon finalization of Tax Act during the current period	0	16,506	0
Additions based on tax positions taken during the current period	8,926	3,133	6,543
Reductions based on tax positions taken during the current period	(259)	(233)	0
Reductions related to settlement of tax matters	0	(136)	(2,921)
Reductions related to a lapse of applicable statute of limitations	(4,492)	(7,087)	(11,895)
Balance at end of year	52,986	35,879	$ 24,361
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued	$ 5,639	$ 4,189