Loans and Leases and the Allowance for Credit Losses - Interest Income Recognized on Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	$ 875,395	$ 981,278	$ 875,219	$ 1,031,664
Interest income recognized, Total	5,596	5,845	21,405	25,140
Interest income recognized, Cash basis	3,350	3,411	14,421	17,416
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			171,227	164,877
Interest income recognized, Total			1,379	6,358
Interest income recognized, Cash basis			1,379	6,358
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			194,337	200,354
Interest income recognized, Total			2,616	1,428
Interest income recognized, Cash basis			2,616	1,428
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			94,453	159,308
Interest income recognized, Total			131	871
Interest income recognized, Cash basis			131	637
Other commercial construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			74,531	97,268
Interest income recognized, Total			1,694	3,322
Interest income recognized, Cash basis			1,694	3,322
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			132,606	184,719
Interest income recognized, Total			7,784	4,795
Interest income recognized, Cash basis			6,146	3,188
Residential Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			135,374	151,992
Interest income recognized, Total			5,002	5,173
Interest income recognized, Cash basis			1,900	1,799
Home equity lines and loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			17,902	12,633
Interest income recognized, Total			540	499
Interest income recognized, Cash basis			182	127
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			36,560	45,075
Interest income recognized, Total			1,742	2,226
Interest income recognized, Cash basis			228	404
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment			18,229	15,438
Interest income recognized, Total			517	468
Interest income recognized, Cash basis			145	153
Commercial, Financial, Leasing, etc. [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	228,749	149,357
Interest income recognized, Total	611	516
Interest income recognized, Cash basis	611	516
Residential Builder and Developer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	90,493	130,855
Interest income recognized, Total	18	213
Interest income recognized, Cash basis	18	188
Other commercial construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	58,500	95,486
Interest income recognized, Total	251	208
Interest income recognized, Cash basis	251	208
Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	104,516	180,995
Interest income recognized, Total	1,328	1,391
Interest income recognized, Cash basis	776	865
Residential Alt-A [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	131,574	147,056
Interest income recognized, Total	1,643	1,763
Interest income recognized, Cash basis	681	692
Home equity lines and loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	19,268	12,810
Interest income recognized, Total	219	167
Interest income recognized, Cash basis	81	49
Automobile [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	33,666	42,957
Interest income recognized, Total	528	710
Interest income recognized, Cash basis	67	127
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	18,677	15,791
Interest income recognized, Total	177	161
Interest income recognized, Cash basis	44	50
Commercial Real Estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Average recorded investment	189,952	205,971
Interest income recognized, Total	821	716
Interest income recognized, Cash basis	$ 821	$ 716