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
Reconciliation of Unrecognized Tax Benefits
Balance of unrecognized tax benefits at beginning of year	$ 28,406	$ 27,237	$ 24,278
Increases for tax positions of prior years	2,784	315	2,478
Decreases for tax positions of prior years	(96)	(61)	(114)
Increases for tax positions established for the current period	2,542	1,185	1,677
Decreases for settlements with taxing authorities	(220)	0	(154)
Reductions resulting from lapse of applicable statute of limitation	(4,462)	(115)	(1,155)
Adjustment resulting from foreign currency translation	46	(155)	227
Balance of unrecognized tax benefits at end of year	$ 29,000	$ 28,406	$ 27,237