Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 7,911	$ 7,527	$ 17,631	$ 16,454
Other comprehensive income (loss), net of tax:
Change in Company-sponsored post-employment benefit plan	(16)	41	(2)	28
Comprehensive income	$ 7,895	$ 7,568	$ 17,629	$ 16,482