Investments (Credit Quality Indicators) (Details) - Commercial and agricultural mortgage loans - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Credit Quality Indicators [Line Items]
Financing Receivable	$ 436,075	$ 420,305
0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	313,280	277,637
60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	95,977	116,176
70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	26,818	26,492
Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Greater than 1.2X
Credit Quality Indicators [Line Items]
Financing Receivable	424,593	403,595
Greater than 1.2X | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	303,215	262,853
Greater than 1.2X | 60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	95,977	115,708
Greater than 1.2X | 70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	25,401	25,034
Greater than 1.2X | Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
1.0X to 1.2X
Credit Quality Indicators [Line Items]
Financing Receivable	10,490	6,221
1.0X to 1.2X | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	9,073	4,295
1.0X to 1.2X | 60%-69.99%
Credit Quality Indicators [Line Items]
Financing Receivable	0	468
1.0X to 1.2X | 70%-79.99%
Credit Quality Indicators [Line Items]
Financing Receivable	1,417	1,458
1.0X to 1.2X | Greater than 80%
Credit Quality Indicators [Line Items]
Financing Receivable	0	0
Less than 1.0X
Credit Quality Indicators [Line Items]
Financing Receivable	992	10,489
Less than 1.0X | 0%-59.99%
Credit Quality Indicators [Line Items]
Financing Receivable	992	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