Loans and Leases (Loans and Leases Outstanding) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Acquired	$ 1,188,281	[1]	$ 1,809,235	[2]
Originated	11,884,585	[2]	11,576,115	[2]
Total loans and leases	13,072,866		13,385,350
Impaired At Acquisition Date
Acquired	159,332		290,626
Commercial
Acquired	914,871		1,450,035
Originated	8,342,100		7,994,495
Commercial | Construction and land development
Acquired	93,963		237,906
Originated	300,266		309,190
Commercial | Mortgage
Acquired	744,349		1,054,473
Originated	6,308,192		6,029,435
Commercial | Commercial and industrial
Acquired	24,448		49,463
Originated	1,009,641		1,038,530
Commercial | Lease financing
Originated	365,967		330,679
Commercial | Other commercial real estate
Acquired	51,108		107,119
Originated	177,599		160,980
Commercial | Other
Acquired	1,003		1,074
Originated	180,435		125,681
Commercial | Impaired At Acquisition Date
Acquired	113,382		217,807
Commercial | Impaired At Acquisition Date | Construction and land development
Acquired	23,136		71,225
Commercial | Impaired At Acquisition Date | Mortgage
Acquired	81,389		107,281
Commercial | Impaired At Acquisition Date | Commercial and industrial
Acquired	144		3,932
Commercial | Impaired At Acquisition Date | Other commercial real estate
Acquired	8,713		35,369
Commercial | Impaired At Acquisition Date | Other
Acquired	0		0
Noncommerical
Acquired	273,410		359,200
Originated	3,542,485		3,581,620
Noncommerical | Mortgage
Acquired	232,310		297,926
Originated	927,426		822,889
Noncommerical | Construction and land development
Acquired	5,337		20,793
Originated	121,553		131,992
Noncommerical | Revolving mortgage
Acquired	34,834		38,710
Originated	2,113,240		2,210,133
Noncommerical | Consumer
Acquired	929		1,771
Originated	380,266		416,606
Noncommerical | Impaired At Acquisition Date
Acquired	45,950		72,819
Noncommerical | Impaired At Acquisition Date | Mortgage
Acquired	32,389		48,077
Noncommerical | Impaired At Acquisition Date | Construction and land development
Acquired	5,145		15,136
Noncommerical | Impaired At Acquisition Date | Revolving mortgage
Acquired	8,416		9,606
Noncommerical | Impaired At Acquisition Date | Consumer
Acquired	$ 0		$ 0

[1] Unaudited

[2] Derived from 2012 Annual Report on Form 10-K.