Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Net income	$ 55,188	$ 61,033
Other comprehensive income (loss), before tax:
Change in net unrealized gain/loss during the period	(21,344)	1,882
Change in net unrealized gain on securities transferred to held to maturity	(8,459)
Reclassification adjustment for net (gains) losses included in net income	(5)	491
Total securities available for sale and transferred securities	(29,808)	2,373
Defined-benefit post-retirement benefit plans:
Change in the net actuarial gain/loss	1,640	1,229
Derivatives:
Change in the accumulated gain/loss on effective cash flow hedge derivatives		(427)
Reclassification adjustments for (gains) losses included in net income:
Interest rate swaps on variable-rate loans	(9,345)	(9,345)
Interest rate swap on junior subordinated deferrable interest debentures	1,085	1,033
Total derivatives	(8,260)	(8,739)
Other comprehensive income (loss), before tax	(36,428)	(5,137)
Deferred tax expense (benefit) related to other comprehensive income	(12,750)	(1,799)
Other comprehensive income (loss), net of tax	(23,678)	(3,338)
Comprehensive income	$ 31,510	$ 57,695