Reinsurance (Cumulative Incurred Claims) (Details) - USD ($)	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cumulative Incurred Claims [Line Items]
Cumulative Incurred Claims	$ 137,800,000
Claims Reserve	$ 1,800,000
Cumulative Number Of Reported Claims	124,370
Incident Year 2015 [Member]
Cumulative Incurred Claims [Line Items]
Cumulative Incurred Claims	$ 33,400,000	$ 33,400,000	$ 33,400,000	$ 33,400,000	$ 33,100,000
Claims Reserve	$ 0
Cumulative Number Of Reported Claims	32,909
Incident Year 2016 [Member]
Cumulative Incurred Claims [Line Items]
Cumulative Incurred Claims	$ 26,000,000.0	26,000,000.0	26,000,000.0	$ 25,700,000
Claims Reserve	$ 0
Cumulative Number Of Reported Claims	25,215
Incident Year 2017 [Member]
Cumulative Incurred Claims [Line Items]
Cumulative Incurred Claims	$ 22,600,000	22,500,000	$ 22,300,000
Claims Reserve	$ 0
Cumulative Number Of Reported Claims	20,461
Incident Year 2018 [Member]
Cumulative Incurred Claims [Line Items]
Cumulative Incurred Claims	$ 25,700,000	$ 25,800,000
Claims Reserve	$ 0
Cumulative Number Of Reported Claims	22,305
Incident Year 2019 [Member]
Cumulative Incurred Claims [Line Items]
Cumulative Incurred Claims	$ 30,100,000
Claims Reserve	$ 1,800,000
Cumulative Number Of Reported Claims	23,480