Unaudited Condensed 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
Statement of Comprehensive Income [Abstract]
Net income	$ 8,022	$ 10,264	$ 20,238	$ 33,257
Reclassification of pension and postretirement adjustments into earnings, net of $29 and $102 tax benefit in the three and nine months ended September 30, 2020, respectively, net of $21 and $66 tax benefit in the three and nine months ended September 30, 2019, respectively.	99	70	355	242
Total other comprehensive income	99	70	355	242
Comprehensive income	$ 8,121	$ 10,334	$ 20,593	$ 33,499