Share Capital and Capital In Excess of Par Value (Details) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 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	$ 892,762	$ 841,094	$ 892,762	$ 841,094
Balance at the end of the period (in shares)	108	105	108	105
Stock dividends (as a percent)	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)	108	105	105	102
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)	108	105	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	$ 847,308	$ 802,253	$ 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	847,308	802,253
Common Stock | Common Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period	$ 29,025	$ 28,619	$ 28,325	$ 27,777
Balance at the beginning of the period (in shares)	41,796	41,211	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	$ 8	$ 1	$ 10	$ 13
Conversion of Class B common shares to common shares (in shares)	12	2	15	18
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	$ 29,033	$ 28,620	$ 29,033	$ 28,620
Balance at the end of the period (in shares)	41,808	41,213	41,808	41,213
Class B Common Stock | Common Stock
Changes in share capital and capital in excess of par value
Balance at the beginning of the period	$ 21,660	$ 21,049	$ 21,032	$ 20,448
Balance at the beginning of the period (in shares)	31,191	30,311	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	$ (8)	$ (1)	$ (10)	$ (13)
Conversion of Class B common shares to common shares (in shares)	(12)	(2)	(15)	(18)
Balance at the end of the period	$ 21,652	$ 21,048	$ 21,652	$ 21,048
Balance at the end of the period (in shares)	31,179	30,309	31,179	30,309