Summary of Significant Accounting Policies, Significant Accounting Policies (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Dec. 31, 2018 USD ($)	Dec. 31, 2020 USD ($) Segment	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Description of Business [Abstract]
Number of reportable segments | Segment		1
Deductible Receivables [Abstract]
Allowance for credit losses, net of tax		$ 1,035
Goodwill and Other Intangible Assets [Abstract]
Goodwill impairment loss	$ 3,152	0	$ 0	$ 3,152
Insurance Company-Owned Life Insurance [Abstract]
Insurance company-owned life insurance		11,458	11,049
Commercial Mortgage Loans [Member]
Investments [Abstract]
Commercial mortgage loans, valuation allowance		195
ASU 2016-13 [Member]
Deductible Receivables [Abstract]
Allowance for credit losses, before tax		16,500	15,000
Allowance for credit losses, net of tax		$ 13,035	$ 11,850