Long-Term Debt (Tables)

12 Months Ended

Dec. 31, 2021

Debt Disclosure [Abstract]

Schedule of Long-Term Debt

Long-term debt at December 31, 2021 and 2020 consisted of the following:

(in thousands)	December 31, 2021			December 31, 2020
Current portion of long-term debt:
Current portion of 5-year term loan facility expires 2026	$	12,500		$	—
Current portion of 5-year term loan facility expires 2022		—			40,000
Current portion of 5-year term loan credit agreement    expires 2023		30,000			30,000
Total current portion of long-term debt		42,500			70,000
Long-term debt:
Note agreements:
4.200% Senior Notes, semi-annual interest payments,    balloon due 2024		499,574			499,416
4.500% Senior Notes, semi-annual interest payments,    balloon due 2029		349,596			349,540
2.375% Senior Note due 2031, semi-annual interest payments, balloon due 2031		699,325			699,252
Total notes		1,548,495			1,548,208
Credit agreements:
5-year term loan facility, periodic interest and principal    payments, LIBOR plus up to 1.750%, expires    October 27, 2026		234,375			—
5-year term loan facility, periodic interest and principal    payments, LIBOR plus up to 1.750%, expires    June 28, 2022		—			250,000
5-year revolving loan facility, periodic interest payments,    currently LIBOR plus up to 1.500%, plus commitment    fees up to 0.225%, expires October 27, 2026		—			—
5-year revolving loan facility, periodic interest payments,    currently LIBOR plus up to 1.500%, plus commitment    fees up to 0.250%, expires June 28, 2022		—			—
5-year term loan facility, periodic interest and principal    payments, LIBOR plus up to 1.750%, expires    December 21, 2023		210,000			240,000
Total credit agreements		444,375			490,000
Debt issuance costs (contra)		(12,433	)		(12,302	)
Total long-term debt less unamortized discount and    debt issuance costs		1,980,437			2,025,906
Current portion of long-term debt		42,500			70,000
Total debt	$	2,022,937		$	2,095,906