Share Capital and Capital In Excess of Par Value (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Changes in share capital and capital in excess of par value
Balance at the beginning of the period	$ 870,409
Balance at the beginning of the period (in shares)	105
Purchase and retirement of common shares and other	$ (6,483)
Purchase and retirement of common shares and other (in shares)	(209)	0
Balance at the end of the period	$ 879,001	$ 834,106
Balance at the end of the period (in shares)	108	105
Stock dividends (as a percent)	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)
Balance at the beginning of the period (in shares)	105	102
Issuance of 3% stock dividend (in shares)	3	3
Balance at the end of the period	$ (1,992)	$ (1,992)
Balance at the end of the period (in shares)	108	105
Capital in Excess of Par Value
Changes in share capital and capital in excess of par value
Balance at the beginning of the period	$ 788,894	$ 737,453
Issuance of 3% stock dividend	64,816	64,800
Purchase and retirement of common shares and other	(6,402)
Balance at the end of the period	847,308	802,253
Class B Common Stock | Common Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period	$ 21,032	$ 20,448
Balance at the beginning of the period (in shares)	30,286	29,445
Issuance of 3% stock dividend	$ 630	$ 613
Issuance of 3% stock dividend (in shares)	908	882
Conversion of Class B common shares to common shares	$ (2)	$ (12)
Conversion of Class B common shares to common shares (in shares)	(3)	(16)
Balance at the end of the period	$ 21,660	$ 21,049
Balance at the end of the period (in shares)	31,191	30,311
Common Stock | Common Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period	$ 28,325	$ 27,777
Balance at the beginning of the period (in shares)	40,789	39,999
Issuance of 3% stock dividend	$ 842	$ 830
Issuance of 3% stock dividend (in shares)	1,213	1,196
Conversion of Class B common shares to common shares	$ 2	$ 12
Conversion of Class B common shares to common shares (in shares)	3	16
Purchase and retirement of common shares and other	$ (144)
Purchase and retirement of common shares and other (in shares)	(209)
Balance at the end of the period	$ 29,025	$ 28,619
Balance at the end of the period (in shares)	41,796	41,211