STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating revenue
Operating revenue	$ 2,536,489	$ 2,477,298	$ 2,382,212
Operating expenses
Operating expenses	2,198,332	2,119,959	2,037,869
Operating income	338,157	357,339	344,343
Investment income
Net investment income	29,753	34,059	29,387
Net realized investment gains (losses)	6,392	6,103	(2,010)
Net impairment losses recognized in earnings	(3,278)	(195)	(1,581)
Total investment income	32,867	39,967	25,796
Interest expense, net	731	856	2,460
Other (expense) income	(1,778)	255	3,641
Income before income taxes	368,515	396,705	371,320
Income tax expense	75,211	79,884	83,096
Net income	$ 293,304	$ 316,821	$ 288,224
Class A common stock
Net income per share
Class A common stock - basic (in dollars per share)	$ 6.30	$ 6.80	$ 6.19
Class A common stock - diluted (in dollars per share)	$ 5.61	$ 6.06	$ 5.51
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	46,188,659	46,188,836	46,188,637
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	52,313,360	52,319,860	52,315,213
Class B common stock
Net income per share
Class A common stock - basic (in dollars per share)	$ 945	$ 1,020	$ 928
Class A common stock - diluted (in dollars per share)	945	1,020	928
Class B common stock - basic and diluted (in dollars per share)	$ 945	$ 1,020	$ 928
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	$ 1,841,794	$ 1,810,457	$ 1,719,567
Operating expenses
Operating expenses	1,588,897	1,537,949	1,457,533
Management fee revenue - administrative services, net
Operating revenue
Operating revenue	59,463	57,204	53,632
Administrative services reimbursement revenue
Operating revenue
Operating revenue	609,435	582,010	580,336
Operating expenses
Operating expenses	609,435	582,010	580,336
Service agreement revenue
Operating revenue
Operating revenue	$ 25,797	$ 27,627	$ 28,677