Comprehensive Income (Components of Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			$ 19,788
Amounts reclassified into net income: Non-credit other-than-temporary impairments on disposed securities	$ 0	$ 780	232	$ 1,085
OCI before reclassifications, Defined Benefit Pension and Post Retirement Plans			0
Amount reclassified into net income: Net actuarial loss	1,110	247	3,332	742
Amounts reclassified from AOCI, HTM Related	(63)	(243)	(353)	(683)
Amounts reclassified from AOCI, All Other	(199)	(10,683)	(10,906)	(18,637)
Other comprehensive (loss) income	6,290	(18,887)	(25,827)	24,274
Other Comprehensive Income, Defined Benefit Pension and Post Retirement Plans, Adjustment, Net of Tax	1,110	$ 247	3,332	742
Ending Balance, September 30, 2015	(6,039)		(6,039)
Available-for-sale Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			80,284
OCI before reclassifications			(18,132)
Other comprehensive (loss) income			(29,038)
Ending Balance, September 30, 2015	51,246		51,246
Investments [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			80,393
OCI before reclassifications			(18,132)
Amounts reclassified from AOCI			(11,027)
Other comprehensive (loss) income			(29,159)
Ending Balance, September 30, 2015	51,234		51,234
Accumulated Other-than-Temporary Impairment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			(514)
OCI before reclassifications			0
Other comprehensive (loss) income			232
Ending Balance, September 30, 2015	(282)		(282)
Accumulated Net Unrealized Investment Gain (Loss) [Member] | Held-to-maturity Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			623
OCI before reclassifications			0
Other comprehensive (loss) income			(353)
Ending Balance, September 30, 2015	270		270
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			(60,605)
Amount reclassified into net income: Net actuarial loss			3,332
Ending Balance, September 30, 2015	(57,273)		(57,273)
Accumulated other comprehensive income (loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning Balance,December 31, 2014			19,788
OCI before reclassifications			(18,132)
Amounts reclassified from AOCI			(7,695)
Other comprehensive (loss) income			(25,827)	$ 24,274
Ending Balance, September 30, 2015	$ (6,039)		$ (6,039)