Allowance for Loan and Lease Losses (Allocation of Allowance for Loan and Lease Losses) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012		Dec. 31, 2012
Financing Receivable, Allowance for Credit Losses [Line Items]
Covered Loans Which Have Adverse Change In Expected Cash Flows	$ 739,900		$ 1,892,721
Total impaired noncovered loans and leases	159,591		112,030		172,984
Unpaid principal balance	174,163		126,877		192,238
Related allowance recorded	96,473		86,117
Allowance for loan and lease losses	273,019	[1]	272,500	[1]	319,018	[2]
Average balance	161,014		116,623
Interest income recognized	2,123		787
Troubled debt restructurings	320,642		318,323		333,170
Construction and Land Development - Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	9,282		19,768		16,057
Unpaid principal balance	20,303		33,430		31,879
Average balance	9,284		23,129
Interest income recognized	112		58
Commercial Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	102,987		63,366		111,808
Unpaid principal balance	105,270		64,551		114,351
Average balance	103,848		64,206
Interest income recognized	1,425		530
Other Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	3,148		1,521		3,248
Unpaid principal balance	3,203		1,521		3,348
Average balance	3,179		2,050
Interest income recognized	45		15
Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	18,520		12,598		18,800
Unpaid principal balance	19,098		12,598		19,196
Average balance	18,997		12,466
Interest income recognized	266		66
Lease Financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	349		79		746
Unpaid principal balance	349		79		746
Average balance	355		201
Interest income recognized	6		1
Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases					707
Unpaid principal balance					707
Revolving Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	5,471				4,203
Unpaid principal balance	5,471				4,203
Average balance	5,472
Interest income recognized	25
Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	17,285		10,438		13,586
Unpaid principal balance	17,921		10,438		13,978
Average balance	17,330		10,107
Interest income recognized	228		90
Construction and Land Development - Non - Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	866		3,345		1,320
Unpaid principal balance	865		3,345		1,321
Average balance	866		3,510
Interest income recognized	11		23
Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	1,683		915		2,509
Unpaid principal balance	1,683		915		2,509
Average balance	1,683		954
Interest income recognized	5		4
With A Recorded Allowance
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	12,512		9,037		16,819
With A Recorded Allowance | Construction and Land Development - Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	458		2,487		2,340
With A Recorded Allowance | Commercial Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	7,896		4,915		10,628
With A Recorded Allowance | Other Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	101		196		279
With A Recorded Allowance | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	2,972		574		1,949
With A Recorded Allowance | Lease Financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	215		4		194
With A Recorded Allowance | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded					53
With A Recorded Allowance | Revolving Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	44				1
With A Recorded Allowance | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	566		674		832
With A Recorded Allowance | Construction and Land Development - Non - Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	81		145		287
With A Recorded Allowance | Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Related allowance recorded	179		42		256
Noncovered Loans | With A Recorded Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	55,452		97,456		68,463
Noncovered Loans | With A Recorded Allowance [Member] | Commercial Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	32,248		54,593		39,648
Noncovered Loans | With A Recorded Allowance [Member] | Other Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	528		1,521		1,425
Noncovered Loans | With A Recorded Allowance [Member] | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	7,055		6,797		7,429
Noncovered Loans | With A Recorded Allowance [Member] | Lease Financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	349		79		665
Noncovered Loans | With A Recorded Allowance [Member] | Other Credit Derivatives [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses					0
Noncovered Loans | With A Recorded Allowance [Member] | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	9,465		10,438		9,346
Noncovered Loans | With A Recorded Allowance [Member] | Revolving Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	1,925				1,238
Noncovered Loans | With A Recorded Allowance [Member] | Construction and Land Development - Non - Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	866		3,345		1,162
Noncovered Loans | With A Recorded Allowance [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	1,683		915		1,609
Noncovered Loans | With A Recorded Allowance [Member] | Construction And Land Development - Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	1,333		19,768		5,941
Noncovered Loans | With No Recorded Allowance [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Total impaired noncovered loans and leases	104,139		14,574		104,521
Noncovered Loans | With No Recorded Allowance [Member] | Commercial Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	70,739		8,773		72,160
Noncovered Loans | With No Recorded Allowance [Member] | Other Commercial Real Estate [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	2,620		0		1,823
Noncovered Loans | With No Recorded Allowance [Member] | Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	11,465		5,801		11,371
Noncovered Loans | With No Recorded Allowance [Member] | Lease Financing
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	0		0		81
Noncovered Loans | With No Recorded Allowance [Member] | Other Credit Derivatives [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses					707
Noncovered Loans | With No Recorded Allowance [Member] | Residential Mortgage
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	7,820		0		4,240
Noncovered Loans | With No Recorded Allowance [Member] | Revolving Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	3,546				2,965
Noncovered Loans | With No Recorded Allowance [Member] | Construction and Land Development - Non - Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	0		0		158
Noncovered Loans | With No Recorded Allowance [Member] | Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	0		0		900
Noncovered Loans | With No Recorded Allowance [Member] | Construction And Land Development - Commercial [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan and lease losses	$ 7,949		$ 0		$ 10,116

[1] Unaudited

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