Stockholders' Equity (Line Items in Consolidated Income Statements Affected by Amounts Reclassified from Accumulated Other Comprehensive Income) (Details) - USD ($) $ in Thousands		3 Months Ended
		Mar. 31, 2016	Mar. 31, 2015
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension and post-retirement items		$ (15,714)	$ (15,634)
Tax effect		(1,115)	(14,876)
Net income		3,839	40,159
Amount Reclassified from Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	[1]	(1,199)	(792)
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Available for Sale Securities [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of AFS securities	[1]	346	165
Tax effect	[1]	(127)	(58)
Net income	[1]	219	107
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | HTM Securities Transferred from AFS [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of unrealized net loss on securities transferred to HTM	[1]	(798)	(647)
Tax effect	[1]	292	238
Net income	[1]	(506)	(409)
Amount Reclassified from Accumulated Other Comprehensive Income [Member] | Employee Benefit Plans [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Amortization of defined benefit pension and post-retirement items	[1],[2]	(1,437)	(770)
Tax effect	[1]	525	280
Net income	[1]	$ (912)	$ (490)

[1] Amounts in parenthesis indicate reduction in net income.

[2] These accumulated other comprehensive income components are included in the computation of net periodic pension and post-retirement cost that is reported with employee benefits expense (see Note 11 for additional details).