Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 6,369	$ 6,308	$ 15,047	$ 13,367
Other comprehensive loss, net of tax:
Company sponsored benefit plans:	(38)	(18)	(77)	(35)
Change in equity method investments	(2)	(3)	(4)	(3)
Other comprehensive loss	(40)	(21)	(81)	(38)
Comprehensive income	$ 6,329	$ 6,287	$ 14,966	$ 13,329