Loans and Allowance for Loan Losses - Impaired Loans Segregated by Class of Loans (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Mar. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	$ 51,195	$ 50,415
Recorded Investment with Allowance	41,833	45,230
Related Allowance	3,026	4,378
Average Recorded Investment	38,853	45,859
Non-residential real estate owner occupied [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	688	580
Recorded Investment with Allowance	601	517
Related Allowance	29	19
Average Recorded Investment	642	732
Non-residential real estate other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	24,355	27,369
Recorded Investment with Allowance	22,680	25,900
Related Allowance	1,734	2,166
Average Recorded Investment	22,915	26,082
Residential real estate permanent mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,068	1,448
Recorded Investment with Allowance	836	1,226
Related Allowance	88	61
Average Recorded Investment	918	1,007
Residential real estate all other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,318	4,631
Recorded Investment with Allowance	1,139	4,246
Related Allowance	218	1,276
Average Recorded Investment	1,335	3,840
Non-consumer non-real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,824	1,899
Recorded Investment with Allowance	1,491	1,565
Related Allowance	427	452
Average Recorded Investment	1,449	2,249
Consumer non-real estate [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	548	441
Recorded Investment with Allowance	527	421
Related Allowance	134	96
Average Recorded Investment	572	408
Other loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	1,215	3,736
Recorded Investment with Allowance	1,198	3,094
Related Allowance	207	267
Average Recorded Investment	1,278	2,648
Acquired loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Unpaid Principal Balance	20,179	10,311
Recorded Investment with Allowance	13,361	8,261
Related Allowance	189	41
Average Recorded Investment	$ 9,744	$ 8,893

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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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