Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net income	$ 33,760	$ 24,476	$ 73,111	$ 50,734
Other comprehensive income (loss):
Foreign currency translation adjustment	2,200	(664)	(883)	1,176
Minimum pension and post retirement benefit plan adjustments	18	12	54	36
Other comprehensive income (loss)	2,218	(652)	(829)	1,212
Total comprehensive income	$ 35,978	$ 23,824	$ 72,282	$ 51,946