Fair Value, Balance Sheet Grouping (Details) - USD ($) $ in Thousands	Mar. 31, 2021	Dec. 31, 2020
Assets [Abstract]
Limited partnerships	$ 7,476	$ 7,214
Carrying Value [Member]
Assets [Abstract]
Limited partnerships	7,476	7,214
Commercial mortgage loans	10,866	10,602
Liabilities [Abstract]
Short-term borrowings	20,000	20,000
Fair Value [Member]
Assets [Abstract]
Limited partnerships	7,476	7,214
Commercial mortgage loans	11,688	11,425
Liabilities [Abstract]
Short-term borrowings	20,000	20,000
Fair Value [Member] | Level 1 [Member]
Assets [Abstract]
Limited partnerships	0	0
Commercial mortgage loans	0	0
Liabilities [Abstract]
Short-term borrowings	0	0
Fair Value [Member] | Level 2 [Member]
Assets [Abstract]
Limited partnerships	0	0
Commercial mortgage loans	0	0
Liabilities [Abstract]
Short-term borrowings	20,000	20,000
Fair Value [Member] | Level 3 [Member]
Assets [Abstract]
Limited partnerships	7,476	7,214
Commercial mortgage loans	11,688	11,425
Liabilities [Abstract]
Short-term borrowings	$ 0	$ 0