Income Taxes - Unrecognized tax benefit (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Reconciliation of activity related to unrecognized tax benefits, excluding interest and penalties:
Unrecognized tax benefits at beginning of year	$ 12,367	$ 11,646	$ 11,049
Gross additions - prior year tax positions	53	0	0
Gross additions - current year tax positions	720	787	801
Gross additions - acquired tax positions	0	659	0
Gross reductions - prior year tax positions	(671)	(248)	(91)
Gross reductions - acquired tax positions settled with tax authorities	(4,647)	(461)	(113)
Impact of change in foreign exchange rates	0	(16)	0
Unrecognized tax benefits at end of year	7,822	12,367	11,646
Liability of interest and penalties	200	3,900	3,300
Income tax (benefit)	13,038	40,600	47,232
Refund from income tax audit	$ 1,200
Beam
Reconciliation of activity related to unrecognized tax benefits, excluding interest and penalties:
Unrecognized tax benefits, would affect the company's future effective tax rate if recognized next 12 months		5,000	5,000
Liability of interest and penalties		$ 3,400	$ 3,000