Amount of investment securities sold at a no gain or loss on sale.

No definition available.

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- Definition

Investment Securities [Line Items]

+ References

No definition available.

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- Definition

Life of mortgage backed securities.

+ References

No definition available.

+ Details

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- Definition

Percentage of aggregate depreciation in unrealized losses.

+ References

No definition available.

+ Details

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- Definition

Investments in notes or bonds that are collateralized by a specific group of underlying assets owned by the issuer of the notes or bonds which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

No definition available.

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- Definition

The total amount of proceeds received for the sale of securities, categorized neither as held-to-maturity nor trading securities, during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27357-111563

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- Definition

Number of investment positions in available-for-sale investments in a continuous unrealized loss position for which an other-than-temporary impairment (OTTI) has not been recognized in the income statement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 6
-Subparagraph (b)(3)
-URI http://asc.fasb.org/extlink&oid=82897076&loc=d3e27290-111563

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- Definition

Debt securities issued by a United States government agency such as Government National Mortgage Association (Ginnie Mae), Federal Home Loan Mortgage Corporation (Freddie Mac), and Federal National Mortgage Association (Fannie Mae), which are short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

+ References

No definition available.

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Investment Securities - Additional Information (Detail)	3 Months Ended	6 Months Ended	9 Months Ended
Investment Securities - Additional Information (Detail)	Sep. 30, 2017 USD ($) Investmentsecurities	Jun. 30, 2017 USD ($)	Sep. 30, 2017 USD ($) Investmentsecurities	Sep. 30, 2016 USD ($)	Dec. 31, 2016 USD ($)
Investment Securities [Line Items]
Investment securities sold		$ 0		$ 0
Investment securities carrying value	$ 268,076,000		$ 268,076,000		$ 292,737,000
Investment securities cost basis	25,757,000
Residential real estate mortgage-backed securities	$ 1,079,060,000		$ 1,079,060,000
Life of mortgage-backed securities			5 years 7 months 6 days
Obligations of U.S. Government Corporations and Agencies [Member]
Investment Securities [Line Items]
Debt securities \| Investmentsecurities	51		51
Percentage of aggregate depreciation in unrealized losses	1.14%		1.14%
Obligations of States and Political Subdivisions [Member]
Investment Securities [Line Items]
Debt securities \| Investmentsecurities	48		48
Percentage of aggregate depreciation in unrealized losses	3.61%		3.61%
Marketable Equity Securities [Member]
Investment Securities [Line Items]
Debt securities \| Investmentsecurities	2		2
Percentage of aggregate depreciation in unrealized losses	1.43%		1.43%