General (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Common stock dividends (in dollars per share)	$ 0.6350	$ 0.6325	$ 1.2700	$ 1.2650
Deferred policy acquisition cost amortization	$ 156,482,000	$ 150,984,000	$ 318,574,000	$ 315,414,000
Advertising expenses	3,800,000	11,600,000	7,800,000	21,400,000
Reinsurance reimbursable amount	25,000,000		$ 25,000,000
Reinsurance Retention Policy, Reinsured Risk, Percentage			73.50%
Reinsurance retention policy, excess retention, amount reinsured			$ 936,000,000
Reinsurance policy, amount retained			60,000,000
Ceded	17,000,000	16,000,000	35,000,000	31,000,000
Losses and loss adjustment expenses, ceded	(6,000,000)	(4,000,000)	(13,000,000)	(3,000,000)
Revenue from contract with customer	4,600,000	5,000,000	9,000,000	11,300,000
Cost of goods and services sold	2,800,000	$ 3,200,000	5,600,000	$ 6,900,000
Contract with customer, asset	0		0		$ 0
Contract with customer, liability	0		0		0
Revenue, remaining performance obligation	$ 0		$ 0		$ 0