Loans - Loans Receivable (Parenthetical) (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	$ 2,048,560	$ 1,938,740
Commercial term includes owner-occupied property loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	774,200	776,300
Commercial lines of credit includes owner-occupied property loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	1,400	936
SBA loans includes owner-occupied property loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Gross Loans	$ 128,400	$ 93,600

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=6375948&loc=d3e4428-111522

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

-Publisher AICPA

-Name Statement of Position (SOP)

-Number 01-6

-Paragraph 13

-Subparagraph e

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant