Investments (Credit Quality Indicators) (Details) - Commercial Mortgage and Agricultural Loans - USD ($) $ in Thousands	Jun. 30, 2015	Dec. 31, 2014
Greater than 1.2X | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	$ 261,502	$ 262,853
Greater than 1.2X | 60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	113,670	115,708
Greater than 1.2X | 70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	22,404	25,034
Greater than 1.2X | Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Greater than 1.2X | Total commercial mortgage and agricultural property loans
Credit Quality Indicators [Line Items]
Financing Receivable	397,576	403,595
1.0X to 1.2X | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	4,175	4,295
1.0X to 1.2X | 60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	1,663	468
1.0X to 1.2X | 70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	0	1,458
1.0X to 1.2X | Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
1.0X to 1.2X | Total commercial mortgage and agricultural property loans
Credit Quality Indicators [Line Items]
Financing Receivable	5,838	6,221
Less than 1.0X | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	1,159	10,489
Less than 1.0X | 60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Less than 1.0X | 70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Less than 1.0X | Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Less than 1.0X | Total commercial mortgage and agricultural property loans
Credit Quality Indicators [Line Items]
Financing Receivable	1,159	10,489
Total | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	266,836	277,637
Total | 60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	115,333	116,176
Total | 70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	22,404	26,492
Total | Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Total | Total commercial mortgage and agricultural property loans
Credit Quality Indicators [Line Items]
Financing Receivable	$ 404,573	$ 420,305