Schedule II - Valuation and Qualifying Accounts (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Balance at the beginning of period	$ 40,857	$ 33,774	$ 28,211
Charged to tax expense/(benefit)	50	6,814	5,557
Purchase accounting adjustments	65	269
Impact of foreign currency exchange rate	32		6
Balance at the end of period	$ 41,004	$ 40,857	$ 33,774