Segment Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
OPERATIONS:
Net interest income	$ 111,349	$ 118,787
Provision for Loan, Lease, and Other Losses	9,946	14,061
Noninterest Income	57,392	51,726
Other expenses	106,925	113,768
Net income	37,346	30,344
AVERAGES :
Assets	14,983,543	14,496,937
Nonreportable segments and reconciling items [Member]
OPERATIONS:
Net interest income	(4,376)	(3,941)
Provision for Loan, Lease, and Other Losses	899	2,195
Noninterest Income	5,462	4,084
Other expenses	817	2,722
Net income	3,221	(503)
AVERAGES :
Assets	4,993,001	5,021,539
Commercial Loan [Member]
OPERATIONS:
Net interest income	65,519	63,853
Provision for Loan, Lease, and Other Losses	4,766	9,104
Noninterest Income	19,232	14,309
Other expenses	43,027	43,351
Net income	24,022	16,709
AVERAGES :
Assets	6,737,236	6,328,473
Retail [Member]
OPERATIONS:
Net interest income	46,431	54,277
Provision for Loan, Lease, and Other Losses	4,073	2,537
Noninterest Income	24,388	25,265
Other expenses	52,907	57,481
Net income	8,996	12,691
AVERAGES :
Assets	3,016,495	2,910,354
Wealth [Member]
OPERATIONS:
Net interest income	3,775	4,598
Provision for Loan, Lease, and Other Losses	208	225
Noninterest Income	8,310	8,068
Other expenses	10,174	10,214
Net income	1,107	1,447
AVERAGES :
Assets	$ 236,811	$ 236,571