CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 155,176	$ 147,334	$ 129,488
Other Comprehensive Income (Loss):
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes of $2,387, $888 and $(1,095), respectively	8,981	3,339	(4,119)
Total other comprehensive income (loss)	8,981	3,339	(4,119)
Comprehensive income	$ 164,157	$ 150,673	$ 125,369