Investments - Securities with Gross Unrealized Loss Position (Details) $ in Thousands	Jun. 30, 2021 USD ($) security
Net Investment Income [Line Items]
Number of securities in an unrealized loss position | security	194
Unrealized loss position for 12 months or longer	0
Debt Securities
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	$ (67)
Less Than Twelve Months, Fair Value	26,609
Total, Gross Unrealized Loss	(67)
Total, Fair Value	26,609
U.S. treasury - held as restricted
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	(2)
Less Than Twelve Months, Fair Value	673
Total, Gross Unrealized Loss	(2)
Total, Fair Value	673
U.S. government obligations
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	(3)
Less Than Twelve Months, Fair Value	1,473
Total, Gross Unrealized Loss	(3)
Total, Fair Value	1,473
Obligations of states, municipalities and political subdivisions
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	(3)
Less Than Twelve Months, Fair Value	1,113
Total, Gross Unrealized Loss	(3)
Total, Fair Value	1,113
Industrial and miscellaneous
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	(16)
Less Than Twelve Months, Fair Value	11,472
Total, Gross Unrealized Loss	(16)
Total, Fair Value	11,472
Residential and commercial mortgage-backed securities
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	(36)
Less Than Twelve Months, Fair Value	8,805
Total, Gross Unrealized Loss	(36)
Total, Fair Value	8,805
Other loan-backed and structured securities
Net Investment Income [Line Items]
Less Than Twelve Months, Gross Unrealized Loss	(7)
Less Than Twelve Months, Fair Value	3,073
Total, Gross Unrealized Loss	(7)
Total, Fair Value	$ 3,073