Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Net income	$ 33,468,000	$ 44,291,000	$ 114,124,000	$ 132,338,000
Other comprehensive income (loss):
Change in unrealized gain (loss) on securities available for sale	(1,460,000)	3,144,000	25,902,000	(56,148,000)
Tax effect and reclassification adjustment	552,000	(1,151,000)	(9,295,000)	20,206,000
Unrealized holding gains (losses) arising during period	(908,000)	1,993,000	16,607,000	(35,942,000)
Non-credit related unrealized gain on other-than-temporarily impaired debt securities	0	237,000	0	378,000
Tax effect	0	(87,000)	0	(139,000)
Reclassification adjustment for gains included in net income	0	150,000	0	239,000
Change in unrealized gain on cash flow hedges	6,329,000	1,309,000	13,902,000	15,795,000
Tax effect	(2,310,000)	(478,000)	(5,074,000)	(5,765,000)
Change in unrealized gain on cash flow hedges	4,019,000	831,000	8,828,000	10,030,000
Changes in postretirement benefit obligations	0	0	0	(26,000)
Tax effect	0	0	0	9,000
Changes in postretirement benefit obligations, net of tax	0	0	0	(17,000)
Total other comprehensive income (loss)	3,111,000	2,974,000	25,435,000	(25,690,000)
Total comprehensive income	$ 36,579,000	$ 47,265,000	$ 139,559,000	$ 106,648,000