Share Capital and Capital In Excess of Par Value (Details) - USD ($) shares in Thousands, $ in Thousands			3 Months Ended		9 Months Ended
	Apr. 05, 2024	Apr. 07, 2023	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Changes in share capital and capital in excess of par value
Balance at the beginning of the period					$ 823,107
Balance at the beginning of the period (in shares)					102
Purchase and retirement of common shares and other					$ (2,196)	$ (27,550)
Purchase and retirement of common shares and other (in shares)					(77)	(747)
Balance at the end of the period			$ 869,830	$ 803,567	$ 869,830	$ 803,567
Balance at the end of the period (in shares)			105	102	105	102
Stock dividends (as a percent)	3.00%	3.00%	3.00%	3.00%	3.00%	3.00%
Treasury Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period			$ (1,992)	$ (1,992)	$ (1,992)	$ (1,992)
Balance at the beginning of the period (in shares)			105	102	102	99
Issuance of 3% stock dividend (in shares)					3	3
Balance at the end of the period			$ (1,992)	$ (1,992)	$ (1,992)	$ (1,992)
Balance at the end of the period (in shares)			105	102	105	102
Capital in Excess of Par Value
Changes in share capital and capital in excess of par value
Balance at the beginning of the period			$ 802,253	$ 753,839	$ 737,453	$ 719,606
Issuance of 3% stock dividend					64,800	50,648
Purchase and retirement of common shares and other			(2,166)	(10,891)	(2,166)	(27,306)
Balance at the end of the period			800,087	742,948	800,087	742,948
Class B Common Stock | Common Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period			$ 21,048	$ 20,453	$ 20,448	$ 19,866
Balance at the beginning of the period (in shares)			30,309	29,452	29,445	28,607
Issuance of 3% stock dividend					$ 613	$ 596
Issuance of 3% stock dividend (in shares)					882	858
Conversion of Class B common shares to common shares			$ (7)		$ (20)	$ (9)
Conversion of Class B common shares to common shares (in shares)			(10)		(28)	(13)
Balance at the end of the period			$ 21,041	$ 20,453	$ 21,041	$ 20,453
Balance at the end of the period (in shares)			30,299	29,452	30,299	29,452
Common Stock | Common Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period			$ 28,620	$ 28,118	$ 27,777	$ 27,584
Balance at the beginning of the period (in shares)			41,213	40,490	39,999	39,721
Issuance of 3% stock dividend					$ 830	$ 823
Issuance of 3% stock dividend (in shares)					1,196	1,185
Conversion of Class B common shares to common shares			$ 7		$ 20	$ 9
Conversion of Class B common shares to common shares (in shares)			10		28	13
Purchase and retirement of common shares and other			$ (53)	$ (221)	$ (53)	$ (519)
Purchase and retirement of common shares and other (in shares)			(77)	(318)	(77)	(747)
Balance at the end of the period			$ 28,574	$ 27,897	$ 28,574	$ 27,897
Balance at the end of the period (in shares)			41,146	40,172	41,146	40,172