STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating revenue
Operating revenue	$ 2,477,298	$ 2,382,212	$ 1,691,774
Operating expenses
Operating expenses	2,119,959	2,037,869	1,401,522
Operating income	357,339	344,343	290,252
Investment income
Net investment income	33,399	30,209	24,639
Net realized investment gains (losses)	6,103	(2,010)	1,334
Net impairment losses recognized in earnings	(195)	(1,581)
Net impairment losses recognized in earnings			(182)
Equity in earnings (losses) of limited partnerships	660	(822)	2,801
Total investment income	39,967	25,796	28,592
Interest expense, net	856	2,460	1,238
Other income (expense)	255	3,641	(1,911)
Income before income taxes	396,705	371,320	315,695
Income tax expense	79,884	83,096	118,696
Net income	$ 316,821	$ 288,224	$ 196,999
Class A Common Stock
Net income per share
Common stock - basic (in dollars per share)	$ 6.80	$ 6.19	$ 4.23
Common stock - diluted (in dollars per share)	$ 6.06	$ 5.51	$ 3.76
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	46,188,836	46,188,637	46,186,831
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	52,319,860	52,315,213	52,337,463
Class B Common Stock
Net income per share
Common stock - basic (in dollars per share)	$ 1,020	$ 928	$ 635
Common stock - diluted (in dollars per share)	$ 1,020	$ 928	$ 634
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	2,542	2,542	2,542
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	2,542	2,542	2,542
Management fee revenue - policy issuance and renewal services, net
Operating revenue
Operating revenue	$ 1,810,457	$ 1,719,567	$ 1,662,625
Operating expenses
Operating expenses	1,537,949	1,457,533	1,401,522
Management fee revenue - administrative services, net
Operating revenue
Operating revenue	57,204	53,632	0
Administrative services reimbursement revenue
Operating revenue
Operating revenue	582,010	580,336	0
Operating expenses
Operating expenses	582,010	580,336	0
Service agreement revenue
Operating revenue
Operating revenue	$ 27,627	$ 28,677	$ 29,149