STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating revenue
Operating revenue	$ 638,742,000	$ 612,126,000	$ 1,880,558,000	$ 1,805,744,000
Operating expenses
Operating expenses	532,835,000	515,431,000	1,591,919,000	1,536,159,000
Operating income	105,907,000	96,695,000	288,639,000	269,585,000
Investment income
Net investment income	8,652,000	7,659,000	25,199,000	21,583,000
Net realized investment gains (losses)	1,696,000	0	5,501,000	(497,000)
Net impairment losses recognized in earnings	(31,000)	0	(193,000)	(646,000)
Equity in earnings of limited partnerships	3,289,000	772,000	2,546,000	361,000
Total investment income	13,606,000	8,431,000	33,053,000	20,801,000
Interest expense, net	111,000	709,000	832,000	1,864,000
Other income	100,000	54,000	195,000	156,000
Income before income taxes	119,502,000	104,471,000	321,055,000	288,678,000
Income tax expense	25,333,000	24,025,000	63,821,000	62,768,000
Net income	$ 94,169,000	$ 80,446,000	$ 257,234,000	$ 225,910,000
Class A common stock
Net income per share
Common stock - basic (in dollars per share)	$ 2.02	$ 1.73	$ 5.52	$ 4.85
Common stock - diluted (in dollars per share)	$ 1.80	$ 1.54	$ 4.92	$ 4.32
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	46,189,006	46,188,941	46,188,767	46,188,522
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	52,325,125	52,317,438	52,317,275	52,313,642
Dividends declared per share
Common stock (in dollars per share)	$ 0.90	$ 0.84	$ 2.70	$ 2.52
Class B common stock
Net income per share
Common stock - basic (in dollars per share)	303	259	829	728
Common stock - diluted (in dollars per share)	$ 303	$ 259	$ 828	$ 727
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)	$ 135.00	$ 126.00	$ 405.00	$ 378.00
Management fee revenue - policy issuance and renewal services, net
Operating revenue
Operating revenue	$ 474,427,000	$ 451,361,000	$ 1,385,923,000	$ 1,311,911,000
Operating expenses
Operating expenses	390,105,000	375,259,000	1,160,614,000	1,103,517,000
Management fee revenue - administrative services, net
Operating revenue
Operating revenue	14,430,000	13,521,000	42,576,000	39,894,000
Administrative services reimbursement revenue
Operating revenue
Operating revenue	142,730,000	140,172,000	431,305,000	432,642,000
Operating expenses
Operating expenses	142,730,000	140,172,000	431,305,000	432,642,000
Service agreement revenue
Operating revenue
Operating revenue	$ 7,155,000	$ 7,072,000	$ 20,754,000	$ 21,297,000