Investments (Mortgage Loans) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 203,855,000	$ 208,899,000
Allowance for possible losses, amount	(675,000)	(650,000)
Totals, amount	$ 203,180,000	$ 208,249,000
Mortgage loans, percentage	100.00%	100.00%
Allowance for possible losses, percentage	(0.30%)	(0.30%)
Totals, percentage	99.70%	99.70%
Less than 50%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 66,371,000	$ 82,224,000
Mortgage loans, percentage	32.60%	39.40%
50% to 60%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 22,610,000	$ 27,395,000
Mortgage loans, percentage	11.10%	13.10%
60% to 70%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 102,857,000	$ 86,849,000
Mortgage loans, percentage	50.40%	41.60%
70% to 80%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 6,642,000	$ 0
Mortgage loans, percentage	3.30%	0.00%
80% to 90%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 5,375,000	$ 6,929,000
Mortgage loans, percentage	2.60%	3.30%
Greater than 90%
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 0	$ 5,502,000
Mortgage loans, percentage	0.00%	2.60%
Retail
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 96,075,000	$ 87,805,000
Mortgage loans, percentage	47.10%	42.00%
Office
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 71,194,000	$ 74,301,000
Mortgage loans, percentage	34.90%	35.60%
Land/Lots
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 3,498,000	$ 10,563,000
Mortgage loans, percentage	1.70%	5.10%
Hotel
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 14,454,000	$ 13,782,000
Mortgage loans, percentage	7.10%	6.60%
All other
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 18,634,000	$ 22,448,000
Mortgage loans, percentage	9.20%	10.70%
West South Central
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 116,205,000	$ 119,794,000
Mortgage loans, percentage	57.00%	57.30%
East North Central
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 20,944,000	$ 30,876,000
Mortgage loans, percentage	10.30%	14.80%
South Atlantic
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 29,829,000	$ 19,155,000
Mortgage loans, percentage	14.60%	9.20%
East South Central
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 13,801,000	$ 14,273,000
Mortgage loans, percentage	6.80%	6.80%
West North Central
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 12,751,000	$ 12,967,000
Mortgage loans, percentage	6.30%	6.20%
Pacific
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 6,626,000	$ 8,014,000
Mortgage loans, percentage	3.20%	3.80%
Middle Atlantic
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 2,138,000	$ 2,215,000
Mortgage loans, percentage	1.00%	1.10%
Mountain
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Mortgage loans, amount	$ 1,561,000	$ 1,605,000
Mortgage loans, percentage	0.80%	0.80%
Mortgage loans
SEC Schedule, 12-29, Real Estate Companies, Investment in Mortgage Loans on Real Estate [Line Items]
Impairment charges	$ 0	$ 0	$ 0