CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 171,180	$ 155,176	$ 147,334
Other Comprehensive Income :
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes of $452, $2,387 and $888, respectively	1,701	8,981	3,339
Total other comprehensive income	1,701	8,981	3,339
Comprehensive income	$ 172,881	$ 164,157	$ 150,673