Credit Commitments and Concentrations of Credit Risk - Loans and Credit Commitments Collateralized by Real Estate (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Commitments And Guarantee Obligations [Line Items]
Loans	$ 1,421,520	$ 1,378,802
Credit commitments	89,802	110,655
Loans and Credit commitments, Total	1,511,322	1,489,457
Residential Property [Member]
Commitments And Guarantee Obligations [Line Items]
Loans	446,424	334,340
Credit commitments	51,302	55,347
Loans and Credit commitments, Total	497,726	389,687
Commercial Property [Member]
Commitments And Guarantee Obligations [Line Items]
Loans	975,096	1,044,462
Credit commitments	38,500	55,308
Loans and Credit commitments, Total	$ 1,013,596	$ 1,099,770

The carrying amount of the outstanding balance due under the mortgage loan.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 205

-SubTopic 10

-Section S99

-Paragraph 6

-Subparagraph (SX 210.5-04.(c) Schedule IV)

-URI http://asc.fasb.org/extlink&oid=27047687&loc=d3e5864-122674

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 29

-Article 12

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph c

-Subparagraph Schedule IV

-Article 5

Reference 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 948

-SubTopic 310

-Section S99

-Paragraph 1

-Subparagraph (SX 210.12-29)

-URI http://asc.fasb.org/extlink&oid=6589523&loc=d3e617274-123014

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