Regulatory Matters - Additional Information (Detail)	Dec. 31, 2015	Dec. 31, 2014
US Government Debt Securities [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Risk Based Capital to Risk Weighted Assets	0.00%
Equity Securities [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Risk Based Capital to Risk Weighted Assets	600.00%
Consolidated Entities [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital to Risk Weighted Assets	14.70%	15.30%
Tier One Risk Based Capital to Risk Weighted Assets	13.90%	14.50%
Tier One Leverage Capital to Average Assets	10.90%	11.00%
Common Equity [Member] \| Consolidated Entities [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Tier One Risk Based Capital to Risk Weighted Assets	12.60%	0.00%

Total Capital divided by risk weighted assets as defined in the regulations.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1H
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

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Tier 1 Leverage Capital divided by average assets as defined in the regulations.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=35709795&loc=SL5958568-112826

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1H
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=35709795&loc=d3e65071-112826

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Tier 1 capital divided by risk weighted assets as defined by regulations.

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