Unaudited Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 10,264	$ 9,200	$ 33,257	$ 23,769
Reclassification of pension and postretirement adjustments into earnings, net of $21 and $66 tax benefit in the three and nine months ended September 30, 2019, respectively, net of $25 and $86 tax benefit in the three and nine months ended September 30, 2018, respectively.	70	103	242	348
Total other comprehensive income	70	103	242	348
Comprehensive income	$ 10,334	$ 9,303	$ 33,499	$ 24,117