STATEMENTS OF OPERATIONS (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating revenue
Operating revenue	$ 647,710	$ 621,458	$ 1,241,816	$ 1,193,618
Operating expenses
Operating expenses	551,100	526,135	1,059,084	1,020,728
Operating income	96,610	95,323	182,732	172,890
Investment income
Net investment income	8,030	7,104	16,547	13,924
Net realized investment gains (losses)	1,302	(32)	3,805	(497)
Net impairment losses recognized in earnings	(84)	(646)	(162)	(646)
Equity in earnings (losses) of limited partnerships	404	(219)	(743)	(411)
Total investment income	9,652	6,207	19,447	12,370
Interest expense, net	272	602	721	1,155
Other income	48	58	95	102
Income before income taxes	106,038	100,986	201,553	184,207
Income tax expense	18,284	21,280	38,488	38,743
Net income	$ 87,754	$ 79,706	$ 163,065	$ 145,464
Class A common stock
Net income per share
Common stock - basic (in dollars per share)	$ 1.88	$ 1.71	$ 3.50	$ 3.12
Common stock - diluted (in dollars per share)	$ 1.68	$ 1.52	$ 3.12	$ 2.78
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	46,188,994	46,188,705	46,188,668	46,188,309
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	52,314,700	52,312,849	52,313,371	52,311,741
Dividends declared per share
Common stock (in dollars per share)	$ 0.90	$ 0.84	$ 1.80	$ 1.68
Class B common stock
Net income per share
Common stock - basic (in dollars per share)	283	257	525	469
Common stock - diluted (in dollars per share)	$ 283	$ 257	$ 525	$ 468
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	$ 270.00	$ 252.00
Management fee revenue - policy issuance and renewal services, net
Operating revenue
Operating revenue	$ 480,513	$ 454,572	$ 911,496	$ 860,550
Operating expenses
Operating expenses	405,005	379,628	770,509	728,258
Management fee revenue - administrative services, net
Operating revenue
Operating revenue	14,195	13,299	28,146	26,373
Administrative services reimbursement revenue
Operating revenue
Operating revenue	146,095	146,507	288,575	292,470
Operating expenses
Operating expenses	146,095	146,507	288,575	292,470
Service agreement revenue
Operating revenue
Operating revenue	$ 6,907	$ 7,080	$ 13,599	$ 14,225