STOCKHOLDERS' EQUITY - AOCI Components (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Changes in accumulated other comprehensive income, net of tax, by component
Balances	$ 1,205,859	$ 983,172	$ 1,151,401	$ 929,067
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	183	(349)	(534)	1,275
Balances	1,211,361	1,063,212	1,211,361	1,063,212
Accumulated Other Comprehensive Income
Changes in accumulated other comprehensive income, net of tax, by component
Balances	6,386	5,323	7,103	3,699
Other comprehensive income (loss) before reclassifications			(40)	1,556
Amounts reclassified from accumulated other comprehensive income			(494)	(281)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	183	(349)	(534)	1,275
Balances	6,569	4,974	6,569	4,974
Unrecognized Net Periodic Benefit Credit
Changes in accumulated other comprehensive income, net of tax, by component
Balances			6,896	4,160
Amounts reclassified from accumulated other comprehensive income			(494)	(281)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			(494)	(281)
Balances	6,402	3,879	6,402	3,879
Interest Rate Swap
Changes in accumulated other comprehensive income, net of tax, by component
Balances			2,604	309
Other comprehensive income (loss) before reclassifications			(421)	1,802
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			(421)	1,802
Balances	2,183	2,111	2,183	2,111
Foreign Currency Translation
Changes in accumulated other comprehensive income, net of tax, by component
Balances			(2,397)	(770)
Other comprehensive income (loss) before reclassifications			381	(246)
OTHER COMPREHENSIVE INCOME (LOSS), net of tax			381	(246)
Balances	$ (2,016)	$ (1,016)	$ (2,016)	$ (1,016)