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Comprehensive Income (Reclassification out of AOCI) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Amounts reclassified into net income: Non-credit OTTI		$ 357
Non-credit OTTI, Tax		(125)
Amounts reclassified into net income: Non-credit OTTI	$ 0	232
Reclassification of net unrealized gains on HTM securities including disposals and amortization	(72)	(261)
Total HTM related, Tax	25	91
Amounts reclassified from AOCI, HTM related	(47)	(170)
Realized losses (gains) on AFS disposals and OTTI	2,699	(19,895)
Total realized losses (gains) on AFS disposals and OTTI	(945)	6,963
Amounts reclassified into net income: realized gains on available for sale securities	1,754	(12,932)
Amount reclassified into net income: Net actuarial loss, Gross	1,516	1,709
Defined pension and other post-retirement benefit plans, Tax	(530)	(598)
Total defined benefit pension and post-retirement plans	986	1,111
Investment Income [Member]
Amortization of net unrealized gains on HTM securities	(100)	(311)
Income Before Federal Income Tax [Member]
Amounts reclassified into net income: Non-credit OTTI	0	357
Reclassification of net unrealized gains on HTM securities including disposals and amortization	(72)	(261)
Realized losses (gains) on AFS disposals and OTTI	2,699	(19,895)
Amount reclassified into net income: Net actuarial loss, Gross	1,516	1,709
Total Federal Income Tax Expense [Member]
Non-credit OTTI, Tax	0	(125)
Total HTM related, Tax	25	91
Total realized losses (gains) on AFS disposals and OTTI	(945)	6,963
Defined pension and other post-retirement benefit plans, Tax	(530)	(598)
Net Income Financial Statement Line Item [Member]
Amounts reclassified into net income: Non-credit OTTI	0	232
Amounts reclassified from AOCI, HTM related	(47)	(170)
Amounts reclassified into net income: realized gains on available for sale securities	1,754	(12,932)
Total defined benefit pension and post-retirement plans	986	1,111
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	2,693	(11,759)
Net Realized Investment Gains [Member]
Unrealized gains and losses on HTM disposals	28	50
Realized losses (gains) on AFS disposals and OTTI	2,699	(19,895)
Net Realized Investment Gains [Member] | Non-credit OTTI on Disposed Securities [Member]
Amounts reclassified into net income: Non-credit OTTI	0	357
Loss And Loss Expense Incurred [Member]
Amount reclassified into net income: Net actuarial loss, Gross	329	371
Policy acquisition costs [Member]
Amount reclassified into net income: Net actuarial loss, Gross	$ 1,187	$ 1,338

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