Schedule III - Supplementary Insurance Information (Details) - Property/Casualty Insurance [Member] - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Supplementary Insurance Information [Abstract]
Deferred policy acquisition costs		$ 9,744	$ 8,496	$ 6,568
Reserves for unpaid claims and claim adjustment expenses		1,089,669	988,305	865,339
Unearned premiums		63,731	74,810	71,625
Other policy claims and benefits payable		0	0	0
Net premium earned		445,515	447,288	432,880
Net investment income	[1]	25,422	26,249	22,048
Benefits, claims, losses and settlement expenses	[1]	318,958	348,468	345,864
Amortization of deferred policy acquisition costs		79,947	81,734	78,105
Other operating expenses	[1],[2]	41,241	34,043	23,514
Net premiums written		$ 441,000	$ 452,242	$ 444,398

[1] Allocations of certain expenses have been made to investment income, settlement expenses and other operating expenses and are based on a number of assumptions and estimates.  Results among these categories would change if different methods were applied.

[2] Commission allowances relating to reinsurance ceded are offset against other operating expenses.