Loans and Leases (Loans Acquired By Loan Class) (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013		Dec. 31, 2012
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	$ 1,188,281	[1]	$ 1,809,235	[2]
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	914,871		1,450,035
Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	93,963		237,906
Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	744,349		1,054,473
Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	51,108		107,119
Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	24,448		49,463
Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,003		1,074
Noncommerical
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	273,410		359,200
Noncommerical | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	232,310		297,926
Noncommerical | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	34,834		38,710
Noncommerical | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	5,337		20,793
Noncommerical | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	929		1,771
Impaired At Acquisition Date
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	159,332		290,626
Impaired At Acquisition Date | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	113,382		217,807
Impaired At Acquisition Date | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	23,136		71,225
Impaired At Acquisition Date | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	81,389		107,281
Impaired At Acquisition Date | Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	8,713		35,369
Impaired At Acquisition Date | Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	144		3,932
Impaired At Acquisition Date | Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		0
Impaired At Acquisition Date | Noncommerical
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	45,950		72,819
Impaired At Acquisition Date | Noncommerical | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	32,389		48,077
Impaired At Acquisition Date | Noncommerical | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	8,416		9,606
Impaired At Acquisition Date | Noncommerical | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	5,145		15,136
Impaired At Acquisition Date | Noncommerical | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	0		0
All Other Acquired Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,028,949		1,518,609
All Other Acquired Loans | Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	801,489		1,232,228
All Other Acquired Loans | Commercial | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	70,827		166,681
All Other Acquired Loans | Commercial | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	662,960		947,192
All Other Acquired Loans | Commercial | Other commercial real estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	42,395		71,750
All Other Acquired Loans | Commercial | Commercial and industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	24,304		45,531
All Other Acquired Loans | Commercial | Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	1,003		1,074
All Other Acquired Loans | Noncommerical
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	227,460		286,381
All Other Acquired Loans | Noncommerical | Mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	199,921		249,849
All Other Acquired Loans | Noncommerical | Revolving mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	26,418		29,104
All Other Acquired Loans | Noncommerical | Construction and land development
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	192		5,657
All Other Acquired Loans | Noncommerical | Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Acquired	$ 929		$ 1,771

[1] Unaudited

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