Loans and Allowance for Loan Losses - Impaired Loans Segregated by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
Jun. 30, 2014	Jun. 30, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 52,683	$ 48,260
Recorded Investment with Allowance	43,517	43,484
Related Allowance	2,927	4,449
Average Recorded Investment	41,938	44,884
Non-residential real estate owner occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	542	814
Recorded Investment with Allowance	476	748
Related Allowance	22	28
Average Recorded Investment	547	623
Non-residential real estate other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	23,886	27,297
Recorded Investment with Allowance	22,122	25,859
Related Allowance	1,710	2,363
Average Recorded Investment	22,305	25,885
Residential real estate permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,117	1,510
Recorded Investment with Allowance	951	1,287
Related Allowance	86	64
Average Recorded Investment	931	1,277
Residential real estate all other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,768	3,694
Recorded Investment with Allowance	1,581	3,294
Related Allowance	215	1,189
Average Recorded Investment	1,310	3,985
Non-consumer non-real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	4,407	1,816
Recorded Investment with Allowance	4,082	1,481
Related Allowance	512	390
Average Recorded Investment	2,151	1,536
Consumer non-real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	568	517
Recorded Investment with Allowance	553	495
Related Allowance	141	79
Average Recorded Investment	542	419
Other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,048	2,253
Recorded Investment with Allowance	880	2,090
Related Allowance	153	278
Average Recorded Investment	1,000	2,648
Acquired loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	19,347	10,359
Recorded Investment with Allowance	12,872	8,230
Related Allowance	88	58
Average Recorded Investment	$ 13,152	$ 8,511

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Average amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 15

-Subparagraph (c)(1)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 17

-URI http://asc.fasb.org/extlink&oid=28368275&loc=d3e5258-111524

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- Definition

Amount of investment of impaired financing receivables with related allowance for credit losses and without a related allowance for credit losses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 50

-Paragraph 14A

-Subparagraph (b)

-URI http://asc.fasb.org/extlink&oid=28368275&loc=SL6953550-111524

+ Details

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- Definition

Amount of allowance for credit losses related to recorded investment.

+ References

+ Details

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- Definition

Amount of unpaid principal balance of impaired financing receivables with related allowance for credit losses and without related allowance for credit losses.

+ References

+ Details

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