Loans and Allowance for Loan Losses - Summary of Changes in Allowance for Loan Losses by Class (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	$ 104,374	$ 100,662	$ 106,120
Charge- Offs	(30,530)	(32,576)	(41,831)
Recoveries	5,850	4,986	2,732
Net Charge- Offs	(24,680)	(27,590)	(39,099)
Provision for loan losses	31,090	31,302	33,641
Balance at End of Year	110,784	104,374	100,662
Originated Loans [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	100,194	100,662	106,120
Charge- Offs	(27,701)	(32,322)	(41,623)
Recoveries	6,226	4,671	2,725
Net Charge- Offs	(21,475)	(27,651)	(38,898)
Provision for loan losses	26,165	27,183	33,440
Balance at End of Year	104,884	100,194	100,662
Acquired Loans [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	4,180
Charge- Offs	(2,829)	(254)	(208)
Recoveries	(376)	315	7
Net Charge- Offs	(3,205)	61	(201)
Provision for loan losses	4,925	4,119	201
Balance at End of Year	5,900	4,180
Commercial Real Estate [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	34,810	43,283	49,924
Charge- Offs	(5,465)	(8,688)	(21,018)
Recoveries	1,799	1,765	594
Net Charge- Offs	(3,666)	(6,923)	(20,424)
Provision for loan losses	1,404	(1,550)	13,783
Balance at End of Year	32,548	34,810	43,283
Commercial and Industrial [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	31,849	25,476	24,682
Charge- Offs	(5,124)	(8,098)	(3,642)
Recoveries	2,108	693	368
Net Charge- Offs	(3,016)	(7,405)	(3,274)
Provision for loan losses	3,770	13,778	4,068
Balance at End of Year	32,603	31,849	25,476
Commercial Leases [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	1,744	1,556	1,070
Charge- Offs	(432)	(509)	(567)
Recoveries	179	224	75
Net Charge- Offs	(253)	(285)	(492)
Provision for loan losses	412	473	978
Balance at End of Year	1,903	1,744	1,556
Total Commercial Loans and Leases [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	68,403	70,315	75,676
Charge- Offs	(11,021)	(17,295)	(25,227)
Recoveries	4,086	2,682	1,037
Net Charge- Offs	(6,935)	(14,613)	(24,190)
Provision for loan losses	5,586	12,701	18,829
Balance at End of Year	67,054	68,403	70,315
Direct Installment [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	15,130	14,814	14,941
Charge- Offs	(9,059)	(7,875)	(8,874)
Recoveries	931	942	876
Net Charge- Offs	(8,128)	(6,933)	(7,998)
Provision for loan losses	10,822	7,249	7,871
Balance at End of Year	17,824	15,130	14,814
Residential Mortgages [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	5,155	4,437	4,578
Charge- Offs	(1,345)	(1,050)	(1,261)
Recoveries	162	194	67
Net Charge- Offs	(1,183)	(856)	(1,194)
Provision for loan losses	1,864	1,574	1,053
Balance at End of Year	5,836	5,155	4,437
Indirect Installment [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	5,449	5,503	5,941
Charge- Offs	(3,337)	(2,926)	(2,957)
Recoveries	773	605	501
Net Charge- Offs	(2,564)	(2,321)	(2,456)
Provision for loan losses	3,524	2,267	2,018
Balance at End of Year	6,409	5,449	5,503
Consumer Lines of Credit [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	6,057	5,447	4,743
Charge- Offs	(1,974)	(2,137)	(2,110)
Recoveries	274	234	213
Net Charge- Offs	(1,700)	(1,903)	(1,897)
Provision for loan losses	2,874	2,513	2,601
Balance at End of Year	7,231	6,057	5,447
Other [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year		146	241
Charge- Offs	(965)	(1,039)	(1,194)
Recoveries		14	31
Net Charge- Offs	(965)	(1,025)	(1,163)
Provision for loan losses	1,495	879	1,068
Balance at End of Year	530		146
Purchased Credit-Impaired Loans [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	759
Charge- Offs	(299)		(208)
Recoveries			7
Net Charge- Offs	(299)		(201)
Provision for loan losses	540	759	201
Balance at End of Year	1,000	759
Other Acquired Loans [Member]
Schedule Of Allowance For Loan Losses [Line Items]
Balance at Beginning of Year	3,421
Charge- Offs	(2,530)	(254)
Recoveries	(376)	315
Net Charge- Offs	(2,906)	61
Provision for loan losses	4,385	3,360
Balance at End of Year	$ 4,900	$ 3,421