Investments (Credit Quality Indicators) (Details) (Commercial Mortgage and Agricultural Loans [Member], USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
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	$ 268,118	$ 262,853
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	115,475	115,708
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	26,145	25,034
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	409,738	403,595
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	4,307	4,295
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	464	468
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	0	1,458
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	4,771	6,221
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	1,240	10,489
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	1,240	10,489
Debt Service Coverage Ratio Total [Member] | Loan To Value Ratio Less Than Fifty Nine Point Nine Nine Percent [Member]
Financing Receivable	273,665	277,637
Debt Service Coverage Ratio Total [Member] | Loan To Value Ratio Sixty Percent To Sixty Nine Point Nine Nine Percent [Member]
Financing Receivable	115,939	116,176
Debt Service Coverage Ratio Total [Member] | Loan-to-Value Ratio, Seventy Percent To Seventy Nine Point Nine Nine Percent [Member]
Financing Receivable	26,145	26,492
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	$ 415,749	$ 420,305