Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Net Income	$ 39,948	$ 41,582	$ 119,757	$ 119,605
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Unrealized gain (loss) on securities	(6,951)	10,834	(43,784)	4,714
Reclassification adjustment for securities (gains) losses included in net income	(1,711)	(28)	(5,181)	(1,840)
Non-credit related unrealized gain (loss) on other-than-temporarily impaired debt securities	(106)	271	1,332	234
Unrealized gain on derivative financial instruments	34	34	102	102
Amortization (accretion) of net unrecognized pension and postretirement plan items	329	214	985	642
Other Comprehensive Income (Loss)	(8,405)	11,325	(46,546)	3,852
Total Comprehensive Income	$ 31,543	$ 52,907	$ 73,211	$ 123,457