Net Income Per Share - Computation of Basic Net Income Per Share and Diluted Net Income Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Numerator for basic and diluted net income per Common Stock and Class B Common Stock share:
Net income	$ 408,375	$ 430,158	$ 189,580
Less dividends:
Total undistributed earnings – basic	361,507	420,784	180,206
Total undistributed earnings – diluted	361,507	420,784	180,206
Class B Common Stock
Less dividends:
Common Stock	5,024	1,312	2,233
Total undistributed earnings – basic	38,758	56,425	42,913
Total undistributed earnings – diluted	39,376	57,626	43,307
Numerator for basic net income per Common Stock share:
Numerator for basic net income per Common Stock share	43,782	57,737	45,146
Numerator for diluted net income per Common Stock share:
Numerator for diluted net income per Common Stock share	$ 44,400	$ 58,938	$ 45,540
Denominator for basic net income per Common Stock and Class B Common Stock share:
Common Stock weighted average shares outstanding - basic (in shares)	1,005	1,257	2,232
Denominator for diluted net income per Common Stock and Class B Common Stock share:
Common Stock weighted average shares outstanding - diluted (in shares)	1,023	1,288	2,259
Basic net income per share:
Common Stock (in dollars per share)	$ 43.56	$ 45.93	$ 20.23
Diluted net income per share:
Common Stock (in dollars per share)	$ 43.40	$ 45.76	$ 20.16
Common Stock
Less dividends:
Common Stock	$ 41,844	$ 8,062	$ 7,141
Total undistributed earnings – basic	322,749	364,359	137,293
Total undistributed earnings – diluted	322,131	363,158	136,899
Numerator for basic net income per Common Stock share:
Numerator for basic net income per Common Stock share	364,593	372,421	144,434
Numerator for diluted net income per Common Stock share:
Numerator for diluted net income per Common Stock share	$ 408,375	$ 430,158	$ 189,580
Denominator for basic net income per Common Stock and Class B Common Stock share:
Common Stock weighted average shares outstanding - basic (in shares)	8,369	8,117	7,141
Denominator for diluted net income per Common Stock and Class B Common Stock share:
Common Stock weighted average shares outstanding - diluted (in shares)	9,392	9,405	9,400
Basic net income per share:
Common Stock (in dollars per share)	$ 43.56	$ 45.88	$ 20.23
Diluted net income per share:
Common Stock (in dollars per share)	$ 43.48	$ 45.74	$ 20.17