Investments (Credit Quality Indicators) (Details) (Commercial Mortgage and Agricultural Loans [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Debt Service Coverage Ratio, Greater than One Point Two X [Member] | Loan To Value Ratio Less Than Fifty Nine Point Nine Nine Percent [Member]
Financing Receivable	$ 262,853	$ 251,278
Debt Service Coverage Ratio, Greater than One Point Two X [Member] | Loan To Value Ratio Sixty Percent To Sixty Nine Point Nine Nine Percent [Member]
Financing Receivable	115,708	102,755
Debt Service Coverage Ratio, Greater than One Point Two X [Member] | Loan-to-Value Ratio, Seventy Percent To Seventy Nine Point Nine Nine Percent [Member]
Financing Receivable	25,034	31,712
Debt Service Coverage Ratio, Greater than One Point Two X [Member] | Loan-to-Value Ratio Greater than Eighty Percent [Member]
Financing Receivable	0	0
Debt Service Coverage Ratio, Greater than One Point Two X [Member] | Loan To Value Ratio Total [Member]
Financing Receivable	403,595	385,745
Debt Service Coverage Ratio, One Point Zero X to Less Than One Point Two X [Member] | Loan To Value Ratio Less Than Fifty Nine Point Nine Nine Percent [Member]
Financing Receivable	4,295	7,650
Debt Service Coverage Ratio, One Point Zero X to Less Than One Point Two X [Member] | Loan To Value Ratio Sixty Percent To Sixty Nine Point Nine Nine Percent [Member]
Financing Receivable	468	0
Debt Service Coverage Ratio, One Point Zero X to Less Than One Point Two X [Member] | Loan-to-Value Ratio, Seventy Percent To Seventy Nine Point Nine Nine Percent [Member]
Financing Receivable	1,458	2,247
Debt Service Coverage Ratio, One Point Zero X to Less Than One Point Two X [Member] | Loan-to-Value Ratio Greater than Eighty Percent [Member]
Financing Receivable	0	0
Debt Service Coverage Ratio, One Point Zero X to Less Than One Point Two X [Member] | Loan To Value Ratio Total [Member]
Financing Receivable	6,221	9,897
Debt Service Coverage Ratio, Less Than One Point Zero X [Member] | Loan To Value Ratio Less Than Fifty Nine Point Nine Nine Percent [Member]
Financing Receivable	10,489	1,865
Debt Service Coverage Ratio, Less Than One Point Zero X [Member] | Loan To Value Ratio Sixty Percent To Sixty Nine Point Nine Nine Percent [Member]
Financing Receivable	0	0
Debt Service Coverage Ratio, Less Than One Point Zero X [Member] | Loan-to-Value Ratio, Seventy Percent To Seventy Nine Point Nine Nine Percent [Member]
Financing Receivable	0	0
Debt Service Coverage Ratio, Less Than One Point Zero X [Member] | Loan-to-Value Ratio Greater than Eighty Percent [Member]
Financing Receivable	0	0
Debt Service Coverage Ratio, Less Than One Point Zero X [Member] | Loan To Value Ratio Total [Member]
Financing Receivable	10,489	1,865
Debt Service Coverage Ratio Total [Member] | Loan To Value Ratio Less Than Fifty Nine Point Nine Nine Percent [Member]
Financing Receivable	277,637	260,793
Debt Service Coverage Ratio Total [Member] | Loan To Value Ratio Sixty Percent To Sixty Nine Point Nine Nine Percent [Member]
Financing Receivable	116,176	102,755
Debt Service Coverage Ratio Total [Member] | Loan-to-Value Ratio, Seventy Percent To Seventy Nine Point Nine Nine Percent [Member]
Financing Receivable	26,492	33,959
Debt Service Coverage Ratio Total [Member] | Loan-to-Value Ratio Greater than Eighty Percent [Member]
Financing Receivable	0	0
Debt Service Coverage Ratio Total [Member] | Loan To Value Ratio Total [Member]
Financing Receivable	$ 420,305	$ 397,507