Asset Size Of Financial Institution

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Coupon Interest Rate

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- Definition

Estimate Of Future Cash Flows Percentage In Year One and Two

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No definition available.

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Estimate Of Future Cash Flows Prepayment Percentage After Year Two

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No definition available.

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- Definition

Excess present value of future cash flows over our current book value.

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No definition available.

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- Definition

Excess subordination as a percentage of current performing collateral.

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No definition available.

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- Definition

Fair Value Input Coupon Rates

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No definition available.

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- Definition

Number of banks and other financial institutions comprising the security.

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No definition available.

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- Definition

Number Of Pooled Securities with No Senior Class

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No definition available.

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- Definition

Number of Securities with Excess Subordination

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No definition available.

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- Definition

Number of Securities with No Excess Subordination

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No definition available.

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- Definition

Current performing collateral related to the security.

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No definition available.

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- Definition

Percentage of principal amount in pooled security securities.

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No definition available.

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- Definition

Percentage Of Total Unrealized Losses

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No definition available.

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- Definition

Probabilities for performing collateral range.

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No definition available.

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- Definition

Probability of default.

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No definition available.

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- Definition

Probability percentage assigned to default bank.

+ References

No definition available.

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- Definition

Probability percentage assigned to default bank subject to market indicators.

+ References

No definition available.

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- Definition

Projected recovery rate.

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No definition available.

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- Definition

Subordinated tranches range.

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No definition available.

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- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=75030427&loc=d3e22054-111558

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 50
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
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-Section 45
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-URI http://asc.fasb.org/extlink&oid=82896770&loc=d3e26610-111562

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- Definition

This item represents the cost of debt and equity securities, which are categorized neither as held-to-maturity nor trading, net of adjustments including accretion, amortization, collection of cash, previous other-than-temporary impairments recognized in earnings (less any cumulative-effect adjustments recognized, as defined), and fair value hedge accounting adjustments, if any.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.2)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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- Definition

This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-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
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- Definition

Rate at which loans or a loan portfolio are expected to prepay principal balances, used as an input to measure fair value.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (bbb)
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- Definition

Federal Home Loan Bank (FHLB) stock represents an equity interest in a FHLB. It does not have a readily determinable fair value because its ownership is restricted and it lacks a market (liquidity).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 325
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=75031641&loc=d3e63345-112809

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- Definition

This item represents reductions in the cumulative amount of credit losses recognized in earnings for an other than temporary impairment (OTTI) of a debt security because of the sale of impaired securities during the period.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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No definition available.

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Impairment of Investment Securities - Additional Information (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Dec. 31, 2017 USD ($) Security Bank	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Schedule of Trading Securities and Other Trading Assets [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost		$ 740,846,000	$ 790,082,000
Estimated Fair Value of Available for Sale		$ 731,358,000	778,612,000
Number of banks and other financial institutions comprising the security \| Bank		206
Number Of Pooled Securities with No Senior Class \| Security		2
Number of Securities with No Excess Subordination \| Security		2
Number of Securities with Excess Subordination \| Security		5
Collateral issued by financial institutions		$ 15,000,000,000
Coupon interest rate		7.00%
Prepayment rate		5.00%
Estimate of future cash flows prepayment percentage in year three		40.00%
Estimate of future cash flows prepayment percentage thereafter		2.00%
Fair Value Input Coupon Rates		10.00%
Probability of default		100.00%
Projected recovery rate		0.00%
Probability percentage assigned to default bank subject to market indicators		10.00%
Probability percentage assigned to default bank		100.00%
Other than-temporary impairment charge		$ 3,958,000	6,671,000	$ 218,000
Other investments		$ 29,837,000	36,498,000
Minimum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Subordinated tranches range		7.00%
Total principal amount of the respective securities		5.00%
Excess subordination as a percentage of current performing collateral		2.00%
Collateral issued by financial institutions		$ 15,000,000,000
Probabilities for performing collateral range		0.33%
Excess percent value of future cash flows over current book value		18.00%
Over Fifteen Million [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Prepayment rate		100.00%
Maximum [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Subordinated tranches range		35.00%
Excess subordination as a percentage of current performing collateral		72.00%
Collateral issued by financial institutions		$ 2,000,000,000
Probabilities for performing collateral range		50.00%
Excess percent value of future cash flows over current book value		104.00%
Pooled Trust Preferred Collateralized Debt Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total unrealized losses		24.00%
Corporate/Mortgage-Backed Securities, Amortized cost		$ 27,499,000	39,989,000
Estimated Fair Value of Available for Sale		23,646,000	33,292,000
Other than-temporary impairment charge		$ 0	0	$ 0
Obligations of U.S. Government-Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total unrealized losses		65.00%
Corporate Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost		$ 15,907,000	5,903,000
Estimated Fair Value of Available for Sale		$ 16,493,000	6,319,000
US States and Political Subdivisions Debt Securities [Member] \| Other Government - Sponsored Enterprises [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Total unrealized losses		10.00%
Debt Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Number of securities in an unrealized loss positions \| Security		98
Estimated Fair Value of Available for Sale		$ 729,688,000	776,942,000
Obligations of U.S. Government-Sponsored Enterprises [Member] \| Mortgage - Backed Securities - Residential [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Number of securities in an unrealized loss positions		0
Equity Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Number of securities in an unrealized loss positions \| Security		0
Corporate/Mortgage-Backed Securities, Amortized cost		$ 1,670,000	1,670,000
Estimated Fair Value of Available for Sale		1,670,000	1,670,000
Corporate Securities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Estimated Fair Value of Available for Sale		$ 16,493,000	6,319,000
Trust Preferred Collateralized Debt Obligations [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Percentage of Current Performing Collateral		0.00%
Mezzanine [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Corporate/Mortgage-Backed Securities, Amortized cost		$ 27,499,000
Estimated Fair Value of Available for Sale		23,646,000
Pre Tsl Xiii [Member] \| Calls And Maturities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale Securities, Gross Realized Losses		$ 4,329,000
Corporate/Mortgage-Backed Securities, Amortized cost			13,171,000
Pre TSL VII [Member] \| Calls And Maturities [Member]
Schedule of Trading Securities and Other Trading Assets [Line Items]
Available-for-sale Securities, Gross Realized Losses	$ 712,000		589,000
Corporate/Mortgage-Backed Securities, Amortized cost			$ 3,119,000