CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
NET INCOME	$ 102,461	$ 60,981	$ 172,030	$ 84,342
Amortization of unrecognized net periodic benefit costs, net of tax of: (2022 - Three-month period $49, Six-month period $97; 2021 - Three-month period $34, Six-month period $69)
Net actuarial gain	(140)	(100)	(281)	(200)
Interest rate swap and foreign currency translation:
Change in unrealized income on interest rate swap, net of tax of: (2022 - Three-month period $121, Six-month period $638; 2021 - Three-month period $59, Six-month period $263)	344	166	1,802	741
Change in foreign currency translation, net of tax of: (2022 - Three-month period $194, Six-month period $86; 2021 - Three-month period $215, Six-month period $333)	(553)	612	(246)	941
OTHER COMPREHENSIVE INCOME (LOSS), net of tax	(349)	678	1,275	1,482
TOTAL COMPREHENSIVE INCOME	$ 102,112	$ 61,659	$ 173,305	$ 85,824