STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating revenue
Operating revenue	$ 2,382,212	$ 1,691,774	$ 1,596,631
Operating expenses
Operating expenses	2,037,869	1,401,522	1,303,114
Operating income	344,343	290,252	293,517
Investment income
Net investment income	30,209	24,639	20,558
Net realized investment (losses) gains	(2,010)	1,334	672
Net impairment losses recognized in earnings	(1,581)	(182)	(416)
Equity in (losses) earnings of limited partnerships	(822)	2,801	7,025
Total investment income	25,796	28,592	27,839
Interest expense, net	2,460	1,238	101
Other income (expense)	3,641	(1,911)	(1,164)
Income before income taxes	371,320	315,695	320,091
Income tax expense	83,096	118,696	109,725
Net income	$ 288,224	$ 196,999	$ 210,366
Class A Common Stock
Net income per share
Common stock - basic (in dollars per share)	$ 6.19	$ 4.23	$ 4.52
Common stock - diluted (in dollars per share)	$ 5.51	$ 3.76	$ 4.01
Weighted average shares outstanding – Basic
Common stock - basic (in shares)	46,188,637	46,186,831	46,188,952
Weighted average shares outstanding – Diluted
Common stock - diluted (in shares)	52,315,213	52,337,463	52,435,303
Class B Common Stock
Net income per share
Common stock - basic (in dollars per share)	$ 928	$ 635	$ 678
Common stock - diluted (in dollars per share)	$ 928	$ 634	$ 677
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
Operating revenue
Operating revenue	$ 1,719,567	$ 1,662,625	$ 1,567,431
Operating expenses
Operating expenses	1,457,533	1,401,522	1,303,114
Management fee revenue, administrative services
Operating revenue
Operating revenue	53,632
Administrative services reimbursements
Operating revenue
Operating revenue	580,336
Operating expenses
Operating expenses	580,336
Service agreement revenue
Operating revenue
Operating revenue	$ 28,677	$ 29,149	$ 29,200