STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Operating revenue
Operating revenue	$ 680,030	$ 657,019	$ 1,310,207	$ 1,273,756
Operating expenses
Operating expenses	594,965	565,830	1,149,047	1,096,876
Operating income	85,065	91,189	161,160	176,880
Investment income
Net investment income	13,650	5,044	30,747	9,708
Net realized investment gains (losses)	2,769	6,526	3,573	(4,280)
Net impairment (losses) recoveries recognized in earnings	(1)	(17)	86	(3,070)
Total investment income	16,418	11,553	34,406	2,358
Interest expense, net	1,039	2	2,048	5
Other expense	548	258	1,067	624
Income before income taxes	99,896	102,482	192,451	178,609
Income tax expense	20,867	20,505	39,856	37,306
Net income	$ 79,029	$ 81,977	$ 152,595	$ 141,303
Earnings per share - Basic and diluted:
Common stock - diluted (in dollars per share)			$ 491
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)			2,542
Class A common stock
Earnings per share - Basic and diluted:
Common stock - basic (in dollars per share)	$ 1.70	$ 1.76	$ 3.28	$ 3.03
Common stock - diluted (in dollars per share)	$ 1.51	$ 1.57	$ 2.92	$ 2.70
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	46,188,289	46,187,808	46,188,573	46,188,299
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	52,302,370	52,302,981	52,309,163	52,313,667
Dividends declared per share
Common stock (in dollars per share)	$ 1.035	$ 0.965	$ 2.070	$ 1.930
Class B common stock
Earnings per share - Basic and diluted:
Common stock - basic (in dollars per share)	255	264	491	455
Common stock - diluted (in dollars per share)	$ 255	$ 264	$ 491	$ 455
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	2,542	2,542	2,542	2,542
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	2,542	2,542	2,542	2,542
Dividends declared per share
Common stock (in dollars per share)	$ 155.25	$ 144.75	$ 310.50	$ 289.50
Management fee revenue - policy issuance and renewal services
Operating revenue
Operating revenue	$ 502,271	$ 483,795	$ 957,989	$ 927,545
Operating expenses
Operating expenses	437,775	413,865	838,324	793,357
Management fee revenue - administrative services
Operating revenue
Operating revenue	14,667	14,813	29,514	29,584
Administrative services reimbursement revenue
Operating revenue
Operating revenue	157,190	151,965	310,723	303,519
Operating expenses
Operating expenses	157,190	151,965	310,723	303,519
Service agreement revenue
Operating revenue
Operating revenue	$ 5,902	$ 6,446	$ 11,981	$ 13,108