Intervest Bancshares (IBCA) 10-Q 30 Apr 14 2014 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2014	Apr. 30, 2014
Document And Entity Information [Abstract]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	31-Mar-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q1	'
Trading Symbol	'IBCA	'
Entity Registrant Name	'INTERVEST BANCSHARES CORP	'
Entity Central Index Key	'0000927807	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	22,022,040

Condensed_Consolidated_Balance

Condensed Consolidated Balance Sheets (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
ASSETS	'	'
Cash and due from banks	$77,592	$16,689
Federal funds sold and other short-term investments	1,565	8,011
Total cash and cash equivalents	79,157	24,700
Time deposits with banks	5,370	5,370
Securities available for sale, at estimated fair value	980	965
Securities held to maturity (estimated fair value of $342,888 and $378,507, respectively)	346,425	383,937
Federal Reserve Bank and Federal Home Loan Bank stock, at cost	8,260	8,244
Loans receivable (net of allowance for loan losses of $27,418 and $27,833, respectively)	1,114,813	1,099,689
Accrued interest receivable	4,630	4,861
Loan fees receivable	2,266	2,298
Premises and equipment, net	4,029	4,056
Foreclosed real estate (net of valuation allowance of $1,193 and $2,017, respectively)	9,335	10,669
Deferred income tax asset	16,317	18,362
Other assets	4,445	4,645
Total assets	1,596,027	1,567,796
Deposits:	'	'
Noninterest-bearing demand deposit accounts	5,570	5,211
Interest-bearing deposit accounts:	'	'
Checking (NOW) accounts	17,763	17,831
Savings accounts	9,706	10,027
Money market accounts	359,457	367,384
Certificate of deposit accounts	911,476	881,779
Total deposit accounts	1,303,972	1,282,232
Long-term debt - subordinated debentures (capital securities)	56,702	56,702
Accrued interest payable on long term debt	67	868
Accrued interest payable on deposits	1,099	1,508
Mortgage escrow funds payable	25,309	18,879
Official checks outstanding	4,685	7,335
Other liabilities	2,549	3,281
Total liabilities	1,394,383	1,370,805
STOCKHOLDERS' EQUITY	'	'
Common stock ($1.00 par value; 62,000,000 shares authorized; 22,021,190 and 21,918,623 shares issued and outstanding, respectively)	22,021	21,919
Additional paid-in-capital, common	88,972	88,043
Unearned compensation on restricted common stock awards	-2,123	-1,898
Retained earnings	92,801	88,959
Accumulated other comprehensive loss	-27	-32
Total stockholders' equity	201,644	196,991
Total liabilities and stockholders' equity	$1,596,027	$1,567,796

Condensed_Consolidated_Balance1

Condensed Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Statement Of Financial Position [Abstract]	'	'
Securities held to maturity, estimated fair value	$342,888	$378,507
Loans receivable, allowance for loan losses	27,418	27,833
Foreclosed real estate, valuation allowance	$1,193	$2,017
Common stock, par value	$1	$1
Common stock, shares authorized	62,000,000	62,000,000
Common stock, shares issued	22,021,190	21,918,623
Common stock, shares outstanding	22,021,190	21,918,623

Condensed_Consolidated_Stateme

Condensed Consolidated Statements of Earnings (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
INTEREST AND DIVIDEND INCOME	'	'
Loans receivable	$14,315	$15,153
Securities	1,181	1,078
Other interest-earning assets	17	18
Total interest and dividend income	15,513	16,249
INTEREST EXPENSE	'	'
Deposits	4,871	6,806
Subordinated debentures - capital securities	399	439
Total interest expense	5,270	7,245
Net interest and dividend income	10,243	9,004
Credit for loan losses	-500	-1,000
Net interest and dividend income credit for loan losses	10,743	10,004
NONINTEREST INCOME	'	'
Income from the early repayment of mortgage loans	508	667
Income from mortgage lending activities	279	371
Customer service fees	79	71
Impairment writedowns on investment securities	'	-366
Total noninterest income	866	743
NONINTEREST EXPENSES	'	'
Salaries and employee benefits	2,242	1,950
Stock compensation for employees and directors	495	254
Occupancy and equipment, net	583	516
Data processing	108	91
Professional fees and services	337	384
Stationery, printing, supplies, postage and delivery	80	61
FDIC insurance	249	505
General insurance	147	152
Director and committee fees	104	104
Advertising and promotion	23	5
Real estate activities expense (income), net	201	-986
Provision for real estate losses	'	629
All other	204	116
Total noninterest expenses	4,773	3,781
Earnings before provision for income taxes	6,836	6,966
Provision for income taxes	2,994	3,075
Net earnings	3,842	3,891
Preferred stock dividend requirements and discount amortization	'	-462
Net earnings available to common stockholders	$3,842	$3,429
Basic earnings per common share	$0.17	$0.16
Diluted earnings per common share	$0.17	$0.16
Cash dividends per common share	'	'

Condensed_Consolidated_Stateme1

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]	'	'
Net earnings	$3,842	$3,891
Other Comprehensive Income:	'	'
Net unrealized holding gain on available-for-sale securities	8	'
Provision for income taxes related to unrealized gain on available-for-sale securities	-3	'
Other comprehensive income, net of tax	5	'
Total comprehensive income	$3,847	$3,891

Condensed_Consolidated_Stateme2

Condensed Consolidated Statements of Changes in Stockholders' Equity (Unaudited) (USD $)	Total	Preferred Stock [Member]	Additional Paid-In-Capital, Preferred [Member]	Preferred Stock Discount [Member]	Common Stock [Member]	Additional Paid-In-Capital, Common [Member]	Unearned Compensation - Restricted Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Loss [Member]
Balance at beginning of period at Dec. 31, 2012	'	$25,000	$24,975,000	($376,000)	$21,590,000	$85,726,000	($715,000)	$79,722,000	'
Balance at beginning of period (in shares) at Dec. 31, 2012	'	25,000	'	'	21,589,589	'	'	'	'
Preferred stockholder's equity	24,720,000	'	'	'	'	'	'	'	'
Preferred stockholder's equity, shares	25,000	'	'	'	'	'	'	'	'
Net earnings	3,891,000	'	'	'	'	'	'	3,891,000	'
Amortization of preferred stock discount	'	'	'	96,000	'	'	'	'	'
Issuance of shares of restricted stock	'	'	'	'	331,000	1,157,000	-1,488,000	'	'
Common stockholders' equity	190,545,000	'	'	'	'	'	'	'	'
Preferred stock discount amortization	-462,000	'	'	'	'	'	'	-96,000	'
Issuance of shares of restricted stock, shares	'	'	'	'	330,700	'	'	'	'
Amortization of unearned compensation to comp expense	'	'	'	'	'	'	251,000	'	'
Common stockholders' equity, shares	21,925,089	'	'	'	'	'	'	'	'
Issuance of shares upon exercise of stock options	'	'	'	'	7,000	21,000	'	'	'
Issuance of shares upon exercise of stock options, shares	'	'	'	'	7,300	'	'	'	'
Forfeiture of shares of restricted stock	'	'	'	'	-3,000	-6,000	'	'	'
Forfeitures of shares of restricted stock issued, shares	'	'	'	'	-2,500	'	'	'	'
Excess income tax benefit from equity awards	145,000	'	'	'	'	145,000	'	'	'
Compensation expense related to stock options	'	'	'	'	'	12,000	'	'	'
Total stockholders' equity at end of period at Mar. 31, 2013	215,265,000	25,000	24,975,000	-280,000	21,925,000	87,055,000	-1,952,000	83,517,000	'
Balance at end of period (in shares) at Mar. 31, 2013	21,950,089	25,000	'	'	21,925,089	'	'	'	'
Balance at beginning of period at Dec. 31, 2013	196,991,000	'	'	'	21,919,000	88,043,000	-1,898,000	88,959,000	-32,000
Balance at beginning of period (in shares) at Dec. 31, 2013	'	'	'	'	21,918,623	'	'	'	'
Net earnings	3,842,000	'	'	'	'	'	'	3,842,000	'
Net change in accumulated other comprehensive loss	5,000	'	'	'	'	'	'	'	5,000
Issuance of shares of restricted stock	'	'	'	'	92,000	612,000	-704,000	'	'
Common stockholders' equity	201,644,000	'	'	'	'	'	'	'	'
Issuance of shares of restricted stock, shares	'	'	'	'	92,000	'	'	'	'
Amortization of unearned compensation to comp expense	'	'	'	'	'	'	479,000	'	'
Common stockholders' equity, shares	22,021,190	'	'	'	'	'	'	'	'
Issuance of shares upon exercise of stock options	'	'	'	'	10,000	20,000	'	'	'
Issuance of shares upon exercise of stock options, shares	10,567	'	'	'	10,567	'	'	'	'
Excess income tax benefit from equity awards	292,000	'	'	'	'	292,000	'	'	'
Compensation expense related to stock options	'	'	'	'	'	5,000	'	'	'
Total stockholders' equity at end of period at Mar. 31, 2014	$201,644,000	'	'	'	$22,021,000	$88,972,000	($2,123,000)	$92,801,000	($27,000)
Balance at end of period (in shares) at Mar. 31, 2014	22,021,190	'	'	'	22,021,190	'	'	'	'

Condensed_Consolidated_Stateme3

Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
OPERATING ACTIVITIES	'	'
Net earnings	$3,842	$3,891
Adjustments to reconcile net earnings to net cash provided by operating activities:	'	'
Depreciation and amortization	96	85
Net credit for loan and real estate losses	-500	-371
Deferred income tax expense	2,042	2,741
Stock compensation expense	495	254
Amortization of deferred debenture offering costs	9	9
Amortization of premiums (accretion) of discounts and deferred loan fees, net	-55	226
Net gain from sale of foreclosed real estate	-72	'
Impairment writedowns on investment securities	'	366
Net decrease in loan fees receivable	32	231
Net (decrease) increase in accrued interest payable on borrowed funds	-801	443
Net decrease in official checks outstanding	-2,650	-3,011
Net change in all other assets and liabilities	-184	174
Net cash provided by operating activities	2,254	5,038
INVESTING ACTIVITIES	'	'
Maturities and calls of securities held to maturity	46,415	49,330
Purchases of securities held to maturity	-9,219	-15,791
Purchases of securities available for sale	-7	-5
Purchases of interest-earning time deposits with banks	'	-200
Purchases of FRB and FHLB stock, net	-16	-10
(Originations) repayments of loans receivable, net	-14,799	24,095
Proceeds from sales of foreclosed real estate	1,406	'
Purchases of premises and equipment, net	-69	-42
Net cash provided by investing activities	23,711	57,377
FINANCING ACTIVITIES	'	'
Net increase (decrease) in deposits	21,740	-44,404
Net increase in mortgage escrow funds payable	6,430	5,366
Proceeds from issuance of common stock upon exercise of stock options	30	28
Excess tax benefit from exercise of options and vesting of restricted stock	292	145
Net cash provided by (used in) financing activities	28,492	-38,865
Net increase in cash and cash equivalents	54,457	23,550
Cash and cash equivalents at beginning of period	24,700	60,395
Cash and cash equivalents at end of period	79,157	83,945
SUPPLEMENTAL DISCLOSURES	'	'
Cash paid for interest	6,471	7,576
Cash paid for income taxes	75	145
Loans transferred to foreclosed real estate	'	3,040
Preferred stock dividend requirements and amortization of related discount	'	$462

Summary_of_Significant_Account

Summary of Significant Accounting Policies	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
Summary of Significant Accounting Policies	'
	Note 1 - Summary of Significant Accounting Policies
	General
	Intervest Bancshares Corporation (“IBC”) is the parent company of Intervest National Bank (“INB”). References in this report to “we,” “us” and “our” refer to these entities on a consolidated basis, unless otherwise specified. For a description of our business, see note 1 to the financial statements in our 2013 Annual Report on Form 10-K (“2013 10-K”). Our accounting and reporting policies conform to U.S. generally accepted accounting principles (GAAP) and general practices within the banking industry and are described in note 1 to the financial statements in our 2013 10-K, as updated by the information in this Form 10-Q.
	Principles of Consolidation and Basis of Presentation
	The condensed consolidated financial statements (“financial statements”) in this report have not been audited except for information derived from our audited 2013 consolidated financial statements and notes thereto and should be read in conjunction with our 2013 10-K. Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted in this report pursuant to the rules and regulations of the Securities and Exchange Commission.
	Use of Estimates
	In preparing our financial statements, we are required to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosure of contingent liabilities as of the date of the financial statements, and revenues and expenses during the reporting periods. Actual results could differ from those estimates. Estimates that are particularly susceptible to significant change currently relate to the determination of our allowance for loan losses, valuation allowance for real estate losses, other than temporary impairment assessments of our security investments and the need for and amount of a valuation allowance for our deferred tax asset. These estimates involve a higher degree of complexity and subjectivity and may require assumptions about highly uncertain matters. Current market conditions increase the risk and complexity of the judgments in these estimates. In our opinion, all material adjustments necessary for a fair presentation of our financial condition and results of operations for the interim periods presented in this report have been made. These adjustments are of a normal recurring nature. All significant intercompany balances and transactions have been eliminated in consolidation. Our results of operations for the interim periods are not necessarily indicative of results that may be expected for the entire year or any other interim period.
	Stock-Based Compensation
	We recognize the cost of our employee and director services received in exchange for awards of our equity instruments (which are in the form of restricted stock, stock options and cash-settled stock appreciation rights or “SARs”) that vest over time based on the grant-date fair value of the awards. The fair value of restricted stock grants is based on the closing market value of our common stock as reported on the Nasdaq Stock Market on the grant date. The fair value of options and SARs is estimated using the Black-Scholes option-pricing model based on various inputs and assumptions that are described in note 9. Compensation cost, or the grant-date fair value of the awards, related to equity awards is recognized on a straight-line basis over the requisite service period, which is normally the vesting period of the grants.
	For SARs only, fair value is re-measured at the end of each reporting period and amortized as compensation cost over the remaining requisite service period less amounts previously recognized. The SARs represent liability-classified awards that are remeasured to reflect their fair value at each reporting period. After the requisite service period is completed, the SAR’s fair value continues to be remeasured each reporting period until settlement and any increase/decrease in the fair value is immediately recognized as an increase/decrease to our reported stock compensation expense. Upon cash-settlement of a SAR, stock compensation expense is trued-up to equal the SAR’s intrinsic cash value on the date of settlement.
	Stock-based compensation associated with equity awards is recorded as stock compensation expense in the statement of earnings and a corresponding increase to stockholders’ equity as additional paid-in capital for amounts related to restricted stock and stock options, and corresponding increase to accrued stock compensation payable for amounts related to the SARs, which is reported as part of our “other liabilities” in our balance sheet.
	For any excess income tax benefit associated with the vesting of restricted common stock awards and the exercise of stock option awards (calculated as the difference between the fair market value of the stock at the vesting date versus the grant date in the case of stock awards and the difference between the fair market value of the stock at the exercise date versus the exercise price per share in the case of options, multiplied by our effective income tax rate) is recorded as decrease to our income taxes payable and an increase in stockholders’ equity as paid-in capital.
	Recent Accounting Standards Update
	In February 2013, the FASB Issued ASU No. 2013-04, “Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation Is Fixed at the Reporting Date”. ASU 2013-04 provides guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for obligations within the scope of this ASU. We adopted this ASU on January 1, 2014 and it had no impact on our financial statements.
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists,” which among other things, requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as denoted within the ASU. The amendments in this ASU are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. We adopted this ASU on January 1, 2014 and it had no impact on our financial statements.
	In January 2014, the FASB issued ASU 2014-04, “Receivables-Troubled Debt Restructurings by Creditors (Subtopic 310-40): Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure”, which is intended to clarify when a creditor should be considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan such that the loan should be derecognized and the real estate recognized. These amendments clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either: (a) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure; or (b) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additional disclosures are required. The amendments are effective for us beginning January 1, 2015.

Securities_Held_to_Maturity_an

Securities Held to Maturity and Available for Sale	3 Months Ended
	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]	'
Securities Held to Maturity and Available for Sale	'
	Note 2 - Securities Held to Maturity and Available for Sale
	The carrying value (amortized cost) and estimated fair value of securities held to maturity (“HTM”) are as follows:
	($ in thousands)		Number of		Amortized		Gross			Gross		Estimated		Wtd-Avg			Wtd-Avg		Wtd-Avg
			Securities		Cost		Unrealized			Unrealized		Fair		Yield			Expected		Remaining
							Gains			Losses		Value					Life		Maturity
	At March 31, 2014
	U.S. government agencies (1)			143	$	267,475	$	359		$	3,529	$	264,305		1	%		3.1 Yrs		3.8 Yrs
	Residential mortgage-backed (2)			63		78,419		310			675		78,054		1.87	%		4.4 Yrs		14.1 Yrs
	State and municipal			1		531		—			2		529		1.25	%		3.0 Yrs		3.0 Yrs
				207	$	346,425	$	669		$	4,206	$	342,888		1.2	%		3.4 Yrs		6.1 Yrs
	At December 31, 2013
	U.S. government agencies (1)			161	$	305,906	$	410		$	4,947	$	301,369		0.94	%		3.0 Yrs		3.8 Yrs
	Residential mortgage-backed (2)			57		77,500		130			1,017		76,613		1.79	%		4.3 Yrs		14.7 Yrs
	State and municipal			1		531		—			6		525		1.25	%		3.2 Yrs		3.3 Yrs
				219	$	383,937	$	540		$	5,970	$	378,507		1.11	%		3.3 Yrs		6.0 Yrs
	-1	Consist of debt obligations of U.S. government sponsored agencies (GSEs)—Federal Home Loan Bank (FHLB), Federal Farm Credit Bank (FFCB), Federal National Mortgage Association (FNMA) and Federal Home Loan Mortgage Corporation (FHLMC), which are federally chartered corporations privately owned by shareholders. GSE securities carry no explicit U.S. government guarantee of creditworthiness. Neither principal nor interest payments are guaranteed by the U.S. government nor do they constitute a debt or obligation of the U.S. government or any of its agencies or instrumentalities other than the applicable GSE. FNMA and FHLMC are under U.S. government conservatorship.
	-2	At March 31, 2014, the portfolio consisted of $12.8 million of Government National Mortgage Association (GNMA) residential pass-through certificates and $65.6 million of residential participation certificates issued by FNMA or FHLMC, compared to $13.6 million and $63.9 million, respectively, at December 31, 2013. The GNMA pass-through certificates are guaranteed as to the payment of principal and interest by the full faith and credit of the U.S. government while the FNMA and FHLMC certificates have an implied guarantee by such agency as to principal and interest payments. Included in this line item are investments in FNMA DUS mortgage-backed securities (of approximately $11 million at March 31, 2014 and $7.0 million at December 31, 2013) that are backed by eligible multifamily pools that typically contain one loan or single purpose entity.
	The estimated fair values of HTM securities with gross unrealized losses segregated between securities that have been in a continuous unrealized loss position for less than twelve months at the respective dates and those that have been in a continuous unrealized loss position for twelve months or longer are summarized as follows:
					Less Than Twelve					Twelve Months or				Total
					Months					Longer
	($ in thousands)		Number		Estimated		Gross			Estimated		Gross		Estimated			Gross
			of		Fair		Unrealized			Fair		Unrealized		Fair			Unrealized
			Securities		Value		Losses			Value		Losses		Value			Losses
	At March 31, 2014
	U.S. government agencies			127	$	227,279	$	3,411		$	6,381	$	118	$	233,660		$	3,529
	Residential mortgage-backed			40		39,011		591			6,451		84		45,462			675
	State and municipal			1		529		2			—		—		529			2
				168	$	266,819	$	4,004		$	12,832	$	202	$	279,651		$	4,206
	At December 31, 2013
	U.S. government agencies			130	$	233,930	$	4,791		$	7,344	$	156	$	241,274		$	4,947
	Residential mortgage-backed			41		48,862		987			3,284		30		52,146			1,017
	State and municipal			1		525		6			—		—		525			6
				172	$	283,317	$	5,784		$	10,628	$	186	$	293,945		$	5,970
	All HTM securities were investment grade rated. The securities had either fixed interest rates or had predetermined scheduled interest rate increases and nearly all had call or prepayment features that allow the issuer to repay all or a portion of the security at par before its stated maturity without penalty. In general, as interest rates rise, the estimated fair value of fixed-rate securities will decrease; as interest rates fall, their value will increase. We generally view changes in fair value caused by changes in interest rates as temporary, which is consistent with our experience. The estimated fair values disclosed in this footnote for HTM securities were obtained from a third-party pricing service that used Level 2 inputs. At March 31, 2014 and December 31, 2013, INB, which owned the HTM portfolio, also had the ability and intent to hold all of the investments for a period of time sufficient for the estimated fair value of the securities with unrealized losses to recover, which may be at the time of maturity. Accordingly, we viewed all the gross unrealized losses related to the HTM portfolio as of those dates to be temporary for the reasons noted above.
	The following table is a summary of the carrying value (amortized cost) and estimated fair value of HTM securities at March 31, 2014, by remaining period to contractual maturity (ignoring earlier call dates, if any). The amounts reported in the table also did not consider the effects of possible prepayments or unscheduled repayments. Accordingly, actual maturities may differ from contractual maturities shown in the table.
	($ in thousands)		Amortized		Estimated		Wtd-Avg
			Cost		Fair Value		Yield
	Due in one year or less		$	8,339	$	8,377		1.32	%
	Due after one year through five years			237,125		234,698		0.96
	Due after five years through ten years			50,439		49,530		1.59
	Due after ten years			50,522		50,283		1.93
			$	346,425	$	342,888		1.2	%
	At March 31, 2014 and December 31, 2013, the carrying value (estimated fair value) of securities available for sale amounted to approximately $1.0 million. The investment represented approximately 92,364 and 91,700 shares, respectively, of an intermediate bond fund that holds securities that are deemed to be qualified under the Community Reinvestment Act.

Loans_Receivable

Loans Receivable	3 Months Ended
	Mar. 31, 2014
Receivables [Abstract]	'
Loans Receivable	'
	Note 3 - Loans Receivable
	Major classifications of loans receivable are summarized as follows:
			At March 31, 2014					At December 31, 2013
	($ in thousands)		# of Loans		Amount			# of Loans		Amount
	Loans Secured By Real Estate:
	Commercial loans			406	$	862,100			394	$	838,766
	Multifamily loans			139		209,593			138		210,270
	One to four family loans			18		64,366			20		72,064
	Land loans			5		9,116			5		9,178
				568		1,145,175			557		1,130,278
	All Other Loans:
	Business loans			18		1,069			19		1,061
	Consumer loans			10		190			12		211
				28		1,259			31		1,272
	Loans receivable, gross			596		1,146,434			588		1,131,550
	Deferred loan fees					(4,203	)				(4,028	)
	Loans receivable, net of deferred fees					1,142,231					1,127,522
	Allowance for loan losses					(27,418	)				(27,833	)
	Loans receivable, net				$	1,114,813				$	1,099,689
	Loans 90 days past due and still accruing interest - At March 31, 2014, there were no loans 90 days past due and still accruing, compared to three loans totaling $4.1 million at December 31, 2013.
	Loans on nonaccrual status - At March 31, 2014 and December 31, 2013, there were $38.7 million and $35.9 million of loans, respectively, on nonaccrual status, which included restructured loans (or “TDRs”) of $32.6 million and $33.2 million, respectively. All the TDRs were current and performing in accordance with their restructured terms but were maintained on nonaccrual status based on regulatory guidance. All of our nonaccrual loans were considered impaired loans.
	TDRs on accrual status - At March 31, 2014 and December 31, 2013, there were $13.3 million and $13.5 million of TDR loans, respectively, classified as accruing TDRs. All of these TDR loans were considered impaired loans.
	At March 31, 2014 and December 31, 2013, we also had one performing and accruing loan of $7.8 million that was classified as an impaired loan.
	The tables below summarize certain information regarding our impaired loans as follows:
	($ in thousands)		Recorded Investment by State (1)																		Specific		Total		# of
																					Valuation		Unpaid		Loans
	At March 31, 2014		NY		FL			VA		GA			CT		OH		SD		Total		Allowance (2)		Principal (3)
	Type
	Retail		$	8,180	$	9,005		$	7,777	$	—		$	2,699	$	985	$	—	$	28,646	$	3,037	$	36,087		7
	Office Building			—		14,349			—		8,695			—		—		—		23,044		1,929		23,044		3
	Parking Lot			2,622		—			—		—			—		—		—		2,622		79		2,622		1
	Multifamily			844		3,118			—		—			—		—		—		3,962		617		3,962		3
	Land			—		—			—		—			—		—		1,590		1,590		48		1,590		1
	Totals		$	11,646	$	26,472		$	7,777	$	8,695		$	2,699	$	985	$	1,590	$	59,864	$	5,710	$	67,305		15
	($ in thousands)		Recorded Investment by State (1)																		Specific		Total		# of
																					Valuation		Unpaid		Loans
	At December 31, 2013		NY		FL			VA		GA			CT		OH		SD		Total		Allowance (2)		Principal (3)
	Type
	Retail		$	8,223	$	9,005		$	7,828	$	—		$	2,719	$	1,000	$	—	$	28,775	$	3,052	$	36,216		7
	Office Building			—		14,937			—		8,695			—		—		—		23,632		1,947		23,632		3
	Multifamily			—		3,128			—		—			—		—		—		3,128		594		3,128		2
	Land			—		—			—		—			—		—		1,625		1,625		500		1,625		1
	Totals		$	8,223	$	27,070		$	7,828	$	8,695		$	2,719	$	1,000	$	1,625	$	57,160	$	6,093	$	64,601		13
	-1	Represents unpaid principal less partial principal charge offs and interest received and applied as a reduction of principal in certain cases.
	-2	Represents a specific valuation allowance against the recorded investment, which is included as part of our overall allowance for loan losses. All impaired loans at the dates indicated in the table had a specific valuation allowance.
	-3	Represents contractual unpaid principal balance (shown for informational purposes only). The borrowers are obligated to pay such amounts. However, the ultimate collection by us of such amounts in this column is not assured.
	Other information related to our impaired loans is summarized as follows:
			For the Quarter Ended March 31,
	($ in thousands)		2014		2013
	Average recorded investment in nonaccrual loans		$	36,464	$	43,705
	Total cash basis interest income recognized on nonaccrual loans			519		598
	Average recorded investment in accruing TDR loans			13,385		17,853
	Total interest income recognized on accruing TDR loans under modified terms			177		250
	Age analysis of our loan portfolio by segment at March 31, 2014 is summarized as follows:
	($ in thousands)		Total		Current			Past Due		Past Due			Past Due		Total
			Portfolio					31-59		60-89			90 or more		Past Due
								Days		Days			Days
	Accruing Loans:
	Commercial real estate		$	824,194	$	819,959		$	4,235	$	—		$	—	$	4,235
	Multifamily			208,749		202,057			6,692		—			—		6,692
	One to four family			64,366		64,366			—		—			—		—
	Land			9,116		9,116			—		—			—		—
	All other			1,259		1,259			—		—			—		—
Total accruing loans			1,107,684		1,096,757			10,927		—			—		10,927
Nonaccrual Loans (1):
Commercial real estate			37,906		35,284			—		2,622			—		2,622
Multifamily			844		—			—		—			844		844
Total nonaccrual loans			38,750		35,284			—		2,622			844		3,466
Total loans		$	1,146,434	$	1,132,041		$	10,927	$	2,622		$	844	$	14,393
-1	The amount of nonaccrual loans in the current column included $32.6 million of TDRs for which payments were being made in accordance with their restructured terms, but the loans were maintained on nonaccrual status in accordance with regulatory guidance. The remaining portion was comprised of certain paying loans classified nonaccrual due to concerns regarding the borrowers’ ability to continue making payments. Interest income from loan payments received on loans in nonaccrual status is recognized on a cash basis, provided the remaining principal balance is deemed collectible.
Age analysis of our loan portfolio by segment at December 31, 2013 is summarized as follows:
($ in thousands)		Total		Current			Past Due		Past Due			Past Due		Total
		Portfolio					31-59		60-89			90 or more		Past Due
							Days		Days			Days
Accruing Loans:
Commercial real estate		$	802,863	$	796,980		$	1,796	$	—		$	4,087	$	5,883
Multifamily			210,270		209,426			844		—			—		844
One to four family			72,064		72,064			—		—			—		—
Land			9,178		9,178			—		—			—		—
All other			1,272		1,271			1		—			—		1
Total accruing loans			1,095,647		1,088,919			2,641		—			4,087		6,728
Nonaccrual Loans (1):
Commercial real estate			35,903		35,903			—		—			—		—
Total nonaccrual loans			35,903		35,903			—		—			—		—
Total loans		$	1,131,550	$	1,124,822		$	2,641	$	—		$	4,087	$	6,728
-1	The amount of nonaccrual loans in the current column included $33.2 million of TDRs for which payments were being made in accordance with their restructured terms, but the loans were maintained on nonaccrual status in accordance with regulatory guidance. The remaining portion was comprised of certain paying loans classified nonaccrual due to concerns regarding the borrowers’ ability to continue making payments. Interest income from loan payments received on loans in nonaccrual status is recognized on a cash basis, provided the remaining principal balance is deemed collectible.
Information regarding the credit quality of the loan portfolio based on our internally assigned grades follows:
($ in thousands)		Pass		Special			Substandard (1)		Total
				Mention
At March 31, 2014
Commercial real estate		$	797,257	$	3,251		$	61,592	$	862,100
Multifamily			202,797		2,365			4,431		209,593
One to four family			64,366		—			—		64,366
Land			7,526		—			1,590		9,116
All other			1,259		—			—		1,259
Total loans		$	1,073,205	$	5,616		$	67,613	$	1,146,434
Allocation of allowance for loan losses		$	20,773	$	166		$	6,479	$	27,418
At December 31, 2013
Commercial real estate		$	772,900	$	3,522		$	62,344	$	838,766
Multifamily			204,298		2,369			3,603		210,270
One to four family			72,064		—			—		72,064
Land			7,553		—			1,625		9,178
All other			1,272		—			—		1,272
Total loans		$	1,058,087	$	5,891		$	67,572	$	1,131,550
Allocation of allowance for loan losses		$	20,720	$	169		$	6,944	$	27,833
-1	Substandard loans consisted of $38.7 million of nonaccrual loans, $12.9 million of accruing TDRs and $16.0 million of other performing loans at March 31, 2014, compared to $35.9 million of nonaccrual loans, $13.1 million of accruing TDRs and $18.6 million of other performing loans at December 31, 2013. At March 31, 2014 and December 31, 2013, we also had one accruing TDR for $0.4 million which was rated pass.
The geographic distribution of the loan portfolio by state follows:
		At March 31, 2014					At December 31, 2013
($ in thousands)		Amount		% of Total			Amount		% of Total
New York		$	653,447		57	%	$	670,052		59.2	%
Florida			331,674		28.9			321,812		28.4
North Carolina			25,988		2.3			22,611		2
Georgia			19,271		1.7			18,799		1.7
New Jersey			15,521		1.4			15,650		1.4
Kentucky			13,846		1.2			11,930		1.1
Pennsylvania			13,370		1.2			16,898		1.5
Virginia			13,240		1.2			11,491		1
Connecticut			10,136		0.9			8,429		0.7
South Carolina			9,167		0.8			9,223		0.8
Massachusetts			6,087		0.5			—		—
Tennessee			5,807		0.5			5,843		0.5
Michigan			5,556		0.5			5,599		0.5
Ohio			4,666		0.4			4,703		0.4
West Virginia			4,500		0.4			—		—
Utah			3,984		0.3			—		—
Indiana			3,644		0.3			2,820		0.2
All other states			6,530		0.5			5,690		0.5
		$	1,146,434		100	%	$	1,131,550		100	%
The distribution of TDRs by accruing versus non-accruing, by loan type and by geographic distribution follows:
($ in thousands)		At March 31, 2014		At December 31, 2013
Performing - nonaccrual status		$	32,585	$	33,184
Performing - accrual status			13,337		13,429
		$	45,922	$	46,613
Commercial real estate		$	41,214	$	41,860
Multifamily			3,118		3,128
Land			1,590		1,625
		$	45,922	$	46,613
New York		$	8,180	$	8,223
Florida			26,472		27,070
Georgia			8,695		8,695
Ohio			985		1,000
South Dakota			1,590		1,625
		$	45,922	$	46,613

Allowance_for_Loan_Losses

Allowance for Loan Losses	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Allowance for Loan Losses	'
	Note 4 - Allowance for Loan Losses
	Activity in the allowance for loan losses by loan type for the periods indicated is as follows:
	($ in thousands)		Commercial			Multifamily			One to Four			Land			All Other		Total
			Real Estate						Family
	Quarter Ended March 31, 2014
	Balance at beginning of period		$	18,403		$	5,097		$	3,017		$	1,308		$	8	$	27,833
	Loan chargeoffs			—			—			—			—			—		—
	Loan recoveries			71			14			—			—			—		85
	Provision (credit) for loan losses			339			1			(385	)		(455	)		—		(500	)
	Balance at end of period		$	18,813		$	5,112		$	2,632		$	853		$	8	$	27,418
	Quarter ended March 31, 2013
	Balance at beginning of period		$	19,051		$	6,881		$	1,120		$	1,043		$	8	$	28,103
	Loan chargeoffs			(115	)		—			—			—			—		(115	)
	Loan recoveries (1)			62			677			—			483			—		1,222
	Provision (credit) for loan losses			(354	)		(1,941	)		1,851			(556	)		—		(1,000	)
	Balance at end of period		$	18,644		$	5,617		$	2,971		$	970		$	8	$	28,210
	-1	In the first quarter of 2013, INB entered into settlement agreements with respect to certain litigation INB had pursued in connection with foreclosure actions it had commenced in 2010 on two of its loans. INB commenced the actions to collect, in one case, insurance proceeds, which it contended had been improperly paid to various third parties, and in another case, damages due to alleged legal malpractice when the loan was originated. As a result of these settlements, INB received net proceeds totaling $2.6 million in the first quarter of 2013, which was recorded as $1.1 million of recoveries of prior loan charge offs and a $1.5 million recovery of prior real estate expenses associated with one of the loans and underlying collateral property.
	The following table sets forth the balances of our loans receivable by segment and impairment evaluation and the allowance for loan losses associated with such loans at March 31, 2014.
	($ in thousands)		Commercial			Multifamily			One to Four			Land			All Other		Total
			Real Estate						Family
	Loans:
	Individually evaluated for impairment		$	54,312		$	3,962		$	—		$	1,590		$	—	$	59,864
	Collectively evaluated for impairment			807,788			205,631			64,366			7,526			1,259		1,086,570
	Total loans		$	862,100		$	209,593		$	64,366		$	9,116		$	1,259	$	1,146,434
	Allowance for loan losses:
	Individually evaluated for impairment (1)		$	5,045		$	617		$	—		$	48		$	—	$	5,710
	Collectively evaluated for impairment			13,768			4,495			2,632			805			8		21,708
	Total allowance for loan losses		$	18,813		$	5,112		$	2,632		$	853		$	8	$	27,418
	-1	See note 3 to financial statements in this report.
	The following table sets forth the balances of our loans receivable by segment and impairment evaluation and the allowance for loan losses associated with such loans at December 31, 2013.
	($ in thousands)		Commercial			Multifamily			One to Four			Land			All Other		Total
			Real Estate						Family
	Loans:
	Individually evaluated for impairment		$	52,407		$	3,128		$	—		$	1,625		$	—	$	57,160
	Collectively evaluated for impairment			786,359			207,142			72,064			7,553			1,272		1,074,390
	Total loans		$	838,766		$	210,270		$	72,064		$	9,178		$	1,272	$	1,131,550
	Allowance for loan losses:
	Individually evaluated for impairment (1)		$	4,999		$	594		$	—		$	500		$	—	$	6,093
	Collectively evaluated for impairment			13,404			4,503			3,017			808			8		21,740
	Total allowance for loan losses		$	18,403		$	5,097		$	3,017		$	1,308		$	8	$	27,833
	-1	See note 3 to financial statements in this report.

Foreclosed_Real_Estate_and_Val

Foreclosed Real Estate and Valuation Allowance for Real Estate Losses	3 Months Ended
	Mar. 31, 2014
Banking And Thrift [Abstract]	'
Foreclosed Real Estate and Valuation Allowance for Real Estate Losses	'
	Note 5 - Foreclosed Real Estate and Valuation Allowance for Real Estate Losses
	Real estate acquired through foreclosure by property type is summarized as follows:
			At March 31, 2014					At December 31, 2013
	($ in thousands)		# of Properties			Amount (1)		# of Properties		Amount (1)
	Commercial real estate			1		$	2,650		2	$	3,984
	Multifamily			1			6,685		1		6,685
	Real estate acquired through foreclosure			2		$	9,335		3	$	10,669
	-1	Reported net of any associated valuation allowance.
	Activity in the valuation allowance for real estate losses is summarized as follows:
			Quarter Ended
			March 31,
	($ in thousands)		2014			2013
	Valuation allowance at beginning of period		$	2,017		$	5,339
	Chargeoffs			(824	)		—
	Provision for real estate losses			—			629
	Valuation allowance at end of period		$	1,193		$	5,968

Deposits

Deposits	3 Months Ended
	Mar. 31, 2014
Banking And Thrift [Abstract]	'
Deposits	'
	Note 6 - Deposits
	Scheduled maturities of certificates of deposit accounts (CDs) are as follows:
		At March 31, 2014					At December 31, 2013
	($ in thousands)	Amount		Wtd-Avg			Amount		Wtd-Avg
				Stated Rate					Stated Rate
	Within one year	$	324,311		1.96	%	$	307,122		1.97	%
	Over one to two years		131,082		1.7			167,323		1.92
	Over two to three years		215,603		1.96			170,956		1.92
	Over three to four years		90,665		2.31			106,700		2.5
	Over four years		149,815		2.04			129,678		2.06
		$	911,476		1.97	%	$	881,779		2.03	%
	CDs of $100,000 or more totaled $506 million at March 31, 2014 and $473 million at December 31, 2013 and included brokered CDs of $87 million and $91 million, respectively. At March 31, 2014, all CDs of $100,000 or more (inclusive of brokered CDs) by remaining maturity were as follows: $147 million due within one year; $62 million due over one to two years; $139 million due over two to three years; $58 million due over three to four years; and $100 million due thereafter. At March 31, 2014, brokered CDs had a weighted average rate of 2.93% and their remaining maturities were as follows: $19 million due within one year; $8 million due over one to two years; $14 million due over two to three years; $25 million due over three to four years and $21 million due over four years.

Lines_of_Credit

Lines of Credit	3 Months Ended
	Mar. 31, 2014
Debt Disclosure [Abstract]	'
Lines of Credit	'
	Note 7 - Lines of Credit
	At March 31, 2014, INB had $41 million of unsecured credit lines that were cancelable by the lender at any time. As a member of the Federal Home Loan Bank of New York (FHLB) and the Federal Reserve Bank of New York (FRB), INB can borrow from these institutions on a secured basis. At March 31, 2014, INB had available collateral consisting of investment securities and certain loans that could be pledged to support additional total borrowings of approximately $368 million from the FHLB and FRB, if needed. There were no borrowings during the reporting periods in this report.

Subordinated_Debentures_Capita

Subordinated Debentures - Capital Securities	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Subordinated Debentures - Capital Securities	'
	Note 8 - Subordinated Debentures - Capital Securities
	Capital Securities (commonly referred to as trust preferred securities) outstanding are summarized as follows:
		At March 31, 2014							At December 31, 2013
	($ in thousands)	Principal		Accrued		Interest			Principal		Accrued		Interest
				Interest		Rate					Interest		Rate
				Payable							Payable
	Capital Securities II - debentures due September 17, 2033	$	15,464	$	20		3.18	%	$	15,464	$	275		3.19	%
	Capital Securities III - debentures due March 17, 2034		15,464		20		3.02	%		15,464		261		3.03	%
	Capital Securities IV - debentures due September 20, 2034		15,464		19		2.63	%		15,464		223		2.65	%
	Capital Securities V - debentures due December 15, 2036		10,310		8		1.88	%		10,310		109		1.89	%
		$	56,702	$	67				$	56,702	$	868
	The securities are obligations of IBC’s wholly owned statutory business trusts, Intervest Statutory Trust II, III, IV and V, respectively. See note 9 to the financial statements included in our 2013 Annual Report on Form 10-K for additional discussion of the above securities.

Common_Stock_Warrant_and_Equit

Common Stock Warrant and Equity Incentive Plans	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Common Stock Warrant and Equity Incentive Plans	'
	Note 9 - Common Stock Warrant and Equity Incentive Plans
	IBC has shareholder-approved equity incentive plans in place under which stock options, restricted stock and other forms of incentive compensation may be awarded from time to time to officers, employees and directors of IBC and its subsidiaries. The maximum number of shares of common stock that may be awarded is 2,250,000. At March 31, 2014, 620,403 shares of common stock were available for award.
	Stock Options and Stock Warrant
	There were no awards of options during the reporting periods in this report.
	A summary of outstanding common stock options and warrant and related information follows:
			Exercise Price Per Warrant/Option																					Wtd-Avg.
																								Exercise
	($ in thousands, except per share amounts)		$5.42 (1)			$17.10			$7.50			$4.02			$3.00			$2.55			Total			Price
	Outstanding at December 31, 2013			691,882			110,640			113,990			57,400			32,400			35,133			1,041,445		$	6.64
	Forfeited/expired (2)			—			(300	)		(300	)		(300	)		(300	)		(200	)		(1,400	)	$	7.14
	Options exercised			—			—			—			(900	)		(4,600	)		(5,067	)		(10,567	)	$	2.87
	Outstanding at March 31, 2014			691,882			110,340			113,690			56,200			27,500			29,866			1,029,478		$	6.68
	Expiration date			12/23/18			12/13/17			12/11/18			12/10/19			12/9/20			12/8/21
	Vested and exercisable (3)			100	%		100	%		100	%		100	%		100	%		67	%		99	%
	Wtd-avg contractual remaining term (in years)			4.7			3.7			4.7			5.7			6.7			7.7			4.9
	Intrinsic value at March 31,		$	1,405		$	—		$	—		$	193		$	122		$	146		$	1,866
	2014 (4)
	-1	The U.S. Department of the Treasury, in connection with IBC’s prior participation in the Capital Purchase Program, owns a warrant to purchase 691,882 shares of IBC’s common stock at an exercise price of $5.42 per share.
	-2	Represent options forfeited or expired unexercised.
	-3	The $2.55 options further vest and become 100% exercisable on December 8, 2014. Full vesting may occur earlier upon the occurrence of certain events as defined in the option agreement.
	-4	Intrinsic value was calculated using the closing price of the common stock on March 31, 2014 of $7.45.
	Restricted Stock
	A summary of selected information regarding awards of restricted common stock during the periods in this report follows:
	($ in thousands, except per share amounts)
	Grant date of award			1/23/14			1/24/13
	Total restricted shares of stock awarded (1)			92,000			330,700
	Grant date per share fair value (2)		$	7.65		$	4.5
	Total estimated fair value of award		$	703,800		$	1,488,150
	Awards scheduled to vest as follows:
	Jan-14			—			49,566
	Jan-15			30,664			170,888
	Jan-16			30,664			110,246
	Jan-17			30,672			—
				92,000			330,700
	-1	For 2014, awards were as follows: a total of 12,000 shares to five executive officers and a total of 80,000 shares to eight non-employee directors (vesting in three equal installments, with one third on each of the next three anniversary dates of the grant).
	For 2013, awards were as follows: a total of 182,000 shares to five executive officers (vesting in two installments, with two thirds vesting on the second anniversary of the grant and the remaining one third on the third anniversary of the grant); a total of 80,000 shares to eight non-employee directors and 68,700 shares to other officers and employees (vesting in three equal installments, with one third on each of the next three anniversary dates of the grant).
	-2	Fair value of each award was based on the closing market price of IBC’s common stock on the grant date.
	A summary of outstanding restricted common stock and related information follows:
																		Wtd-Avg.
			Price Per Share															Price
			$2.90			$4.50			$7.21			$7.65			Total			Per Share
	Outstanding at December 31, 2013			158,317			279,500			135,500			—			573,317		$	4.7
	Shares vested and no longer restricted			(101,035	)		(47,664	)		(75,417	)		—			(224,116	)	$	4.69
	Shares granted			—			—			—			92,000			92,000		$	7.65
	Outstanding at March 31, 2014 (1) (2)			57,282			231,836			60,083			92,000			441,201		$	5.32
	-1	All outstanding shares of restricted common stock at March 31, 2014 were unvested and subject to forfeiture.
	Shares issued at $2.90 vest: 57,282 on January 19, 2015.
	Shares issued at $4.50 vest: 138,664 on January 24, 2015; 93,172 on January 24, 2016.
	Shares issued at $7.21 vest: 14,584 on January 19, 2015; 30,333 on January 24, 2015; 15,166 on January 24, 2016.
	Shares issued at $7.65 vest: 30,664 on January 23, 2015; 30,664 on January 23, 2016; 30,672 on January 23, 2017.
	-2	Vesting is subject to the grantee’s continued employment with us or, in the case of non-employee directors, the grantee’s continued service as our director on the vesting dates. All of the awards are subject to accelerated vesting upon the death or disability of the grantee or upon a change in control of IBC, as defined in the restricted stock agreements. The record holder of IBC’s restricted shares of common stock possesses all the rights of a holder of our common stock, including the right to receive dividends on the shares when declared and to vote the restricted shares. The restricted shares may not be sold, transferred, pledged, assigned, encumbered, or otherwise alienated or hypothecated until they become fully vested and transferable in accordance with the agreements.
	Stock Appreciations Rights
	On January 23, 2014, Cash-Settled Stock Appreciation Rights (or “SARs”) were awarded to five executive officers in the total amount of 78,000 shares. The SARs have an exercise price of $7.65 per share, a contractual term of 5 years from the date of grant, upon which they expire, and they vest in three equal installments on the first, second and third anniversaries of the grant date. The SARs are exercisable for thirty days after the holder terminates service to our Company, unless such termination is due to the holder’s death or disability, in which case the SARs are exercisable for one year after termination. The SARs give the executive the right to receive upon exercise, an amount payable in cash equal to the number of shares subject to the SAR that is being exercised multiplied by the excess of (a) the fair market value of a share of our common stock on the date the SAR is exercised, over (b) the exercise price specified in the SAR agreement, which in the case of this award is $7.65. The estimated fair value of each SAR on the date of grant was $2.28, or a total estimated fair value of $178,000 as calculated using the Black-Scholes option pricing model with the following assumptions used as inputs into the model: expected dividend yield of 1.75%; expected stock volatility of 45%; risk-free interest rate of 0.98% and an expected term of 3.5 years.
	Stock Compensation Expense and Excess Tax Benefit
	Stock-based compensation expense related to all equity awards totaled $495,000 and $254,000 for the first quarter of 2014 and 2013, respectively. The expense for the 2014 first quarter included $11,000 attributable to outstanding cash-settled SARs. At March 31, 2014, pre-tax compensation expense related to all non-vested equity awards not yet recognized totaled $2.3 million and such amount is expected to be recognized in the future over a weighted-average period of approximately 2.1 years.
	Our income taxes payable was reduced by the excess income tax benefit arising from the vesting of restricted common stock awards and the exercise of stock option awards during the reporting periods in this report based on certain criteria as described in note 1 to the financial statements. The tax benefit amounted to $292,000 and $145,000 for the first quarter of 2014 and 2013, respectively.

Earnings_Per_Common_Share

Earnings Per Common Share	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Earnings Per Common Share	'
	Note 10 - Earnings Per Common Share
	Net earnings applicable to common stockholders and the weighted-average number of shares used for basic and diluted earnings per common share computations are summarized in the table that follows:
			Quarter Ended
			March 31,
			2014		2013
	Basic Earnings Per Common Share:
	Net earnings available to common stockholders		$	3,842,000	$	3,429,000
	Weighted-Average number of common shares outstanding			21,991,451		21,832,200
	Basic Earnings Per Common Share		$	0.17	$	0.16
	Diluted Earnings Per Common Share:
	Net earnings applicable to common stockholders		$	3,842,000	$	3,429,000
	Weighted-Average number of common shares outstanding:
	Common shares outstanding			21,991,451		21,832,200
	Potential dilutive shares resulting from exercise of			229,050		22,255
	warrants/options (1)
	Total average number of common shares outstanding used for dilution			22,220,501		21,854,455
	Diluted Earnings Per Common Share		$	0.17	$	0.16
	-1	All outstanding options/warrants to purchase shares of our common stock were considered for the Diluted EPS computations and only those that were dilutive (as determined by using the treasury stock method prescribed by GAAP) were included in the computations above. In the 2014 and 2013 periods, 110,340 and 928,112 of options/warrants to purchase common stock, respectively, were not dilutive because the exercise price of each was above the average market price of our common stock during these periods.

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2014
Commitments And Contingencies Disclosure [Abstract]	'
Contingencies	'
	Note 11 - Contingencies
	We are periodically a party to or otherwise involved in legal proceedings arising in the normal course of business, such as foreclosure proceedings. Based on review and consultation with our legal counsel, we do not believe that there is any pending or threatened proceeding against us, which, if determined adversely, would have a material effect on our business, results of operations, financial position or liquidity.

Regulatory_Matters_and_Regulat

Regulatory Matters and Regulatory Capital	3 Months Ended
	Mar. 31, 2014
Banking And Thrift [Abstract]	'
Regulatory Matters and Regulatory Capital	'
	Note 12 - Regulatory Matters and Regulatory Capital
	On March 7, 2014, IBC received notification from the Federal Reserve Bank of New York (the “FRB”) that the written agreement between IBC and the FRB that was in effect since January 14, 2011 was terminated. As a result, IBC is no longer subject to any regulatory agreement or related restrictions that were described in our 2013 10-K.
	At March 31, 2014, IBC’s consolidated Tier 1 capital and total capital ratios were 20.64% and 21.90%, respectively, and its leverage capital ratio was 16.12%. At March 31, 2014, INB’s leverage capital ratio, Tier 1 capital and total capital ratios were 15.55%, 19.84% and 21.10%, respectively. At March 31, 2014, we believe that IBC and INB met all regulatory capital adequacy requirements to which they were subject. As of the date of filing of this report, we are not aware of any conditions or events that would have changed the status of such compliance with those requirements at March 31, 2014.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Fair Value Measurements	'
	Note 13 - Fair Value Measurements
	We use fair value measurements to record fair value adjustments to certain of our assets and to determine our fair value disclosures. In accordance with GAAP, we group our assets and liabilities measured at fair value into three levels (Level 1, 2 and 3), based on the markets in which they are traded and the reliability of the assumptions and inputs that are used to determine their fair value. Level 1 has the highest level of reliability because fair value is based on actively traded markets. See note 20 to the financial statements included in our 2013 10-K for a further discussion of the three valuation levels.
	At March 31, 2014 and December 31, 2013, we had no liabilities recorded at fair value and approximately $1.0 million of assets (comprised of securities available for sale) recorded at fair value (Level 1) on a recurring basis.
	The following tables provide information regarding our assets measured at fair value on a nonrecurring basis.
			Outstanding Carrying Value
			At Mar 31, 2014			At Dec 31, 2013
	($ in thousands)		Level 3			Level 3
	Impaired loans (1) :
	Commercial real estate		$	54,312		$	52,407
	Multifamily			3,962			3,128
	Land			1,590			1,625
	Total impaired loans			59,864			57,160
	Foreclosed real estate			9,335			10,669
									Total Losses (Gains) (2)
			Accumulated Losses on						Quarter Ended
			Outstanding Balance						March 31,
	($ in thousands)		At Mar			At Dec			2014			2013
			31, 2014			31, 2013
	Impaired loans:
	Commercial real estate		$	11,498		$	11,522		$	(24	)	$	389
	Multifamily			617			594			23			(423	)
	Land			48			500			(452	)		(14	)
	Total impaired loans			12,163			12,616			(453	)		(48	)
	Impaired securities			—			—			—			366
	Foreclosed real estate			1,193			2,017			(72	)		629
	-1	Outstanding carrying value excludes a specific valuation allowance. See note 4 to the financial statements in this report.
	-2	Represents total losses or (gains) recognized on all assets measured at fair value on a nonrecurring basis during the period indicated. The losses or (gains) for impaired loans represent the change (before chargeoffs and recoveries) during the period in the corresponding specific valuation allowance, while the losses (gains) for foreclosed real estate represent writedowns in carrying values subsequent to foreclosure (recorded as provisions for real estate losses) adjusted for any recoveries of prior write downs and (gains) or losses from the transfer/sale of properties during the period. The losses on securities represent the total of other than temporary impairment charges, which are recorded as component of noninterest income.
	The following table presents information regarding the change in assets measured at fair value on a nonrecurring basis for the periods indicated.
	($ in thousands)		Impaired			Impaired			Foreclosed
			Securities			Loans			Real Estate
	Quarter Ended March 31, 2014
	Balance at beginning of period		$	—		$	57,160		$	10,669
	Net new impaired loans			—			3,466			—
	Principal repayments/sales			—			(762	)		(1,406	)
	Gain from sales			—			—			72
	Balance at end of period		$	—		$	59,864		$	9,335
	Quarter Ended March 31, 2013
	Balance at beginning of period		$	3,721		$	65,973		$	15,923
	Net new impaired loans			—			1,485			—
	Principal repayments/sales			(63	)		(9,467	)		—
	Chargeoffs			—			(115	)		—
	Transferred to foreclosed real estate			—			(3,040	)		3,040
	Other than temporary impairment writedowns			(366	)		—			—
	Writedowns of carrying value subsequent to foreclosure			—			—			(629	)
	Balance at end of period		$	3,292		$	54,836		$	18,334
	We are required to disclose the estimated fair value of each class of our financial instruments for which it is practicable to estimate, which values are shown in the table that follows. The fair value of a financial instrument is the current estimated amount that would be exchanged between willing parties, other than in a forced liquidation. The fair value estimates are made at a specific point in time based on available information. A discussion regarding the assumptions used to compute the estimated fair values disclosed below can be found in note 20 to the financial statements included our 2013 10-K.
	The carrying and estimated fair values of our financial instruments are as follows:
			At March 31, 2014						At December 31, 2013
	($ in thousands)		Carrying			Fair			Carrying			Fair
			Value			Value			Value			Value
	Financial Assets:
	Cash and cash equivalents (1)		$	79,157		$	79,157		$	24,700		$	24,700
	Time deposits with banks (1)			5,370			5,370			5,370			5,370
	Securities available for sale, net (1)			980			980			965			965
	Securities held to maturity, net (2)			346,425			342,888			383,937			378,507
	FRB and FHLB stock (3)			8,260			8,260			8,244			8,244
	Loans receivable, net (3)			1,114,813			1,119,116			1,099,689			1,100,858
	Accrued interest receivable (3)			4,630			4,630			4,861			4,861
	Loan fees receivable (3)			2,266			1,788			2,298			1,808
	Total Financial Assets		$	1,561,901		$	1,562,189		$	1,530,064		$	1,525,313
	Financial Liabilities:
	Deposits (3)		$	1,303,972		$	1,316,092		$	1,282,232		$	1,294,690
	Borrowed funds plus accrued interest payable (3)			56,769			56,460			57,570			57,260
Accrued interest payable on deposits (3)			1,099			1,099			1,508			1,508
Commitments to lend (3)			450			450			408			408
Total Financial Liabilities		$	1,362,290		$	1,374,101		$	1,341,718		$	1,353,866
Net Financial Assets		$	199,611		$	188,088		$	188,346		$	171,447
-1	We consider these fair value measurements to be Level 1.
-2	We consider these fair value measurements to be Level 2.
-3	We consider these fair value measurements to be Level 3.

Subsequent_Event

Subsequent Event	3 Months Ended
	Mar. 31, 2014
Subsequent Events [Abstract]	'
Subsequent Event	'
	Note 14 - Subsequent Event
	On April 24, 2014, IBC’s Board of Directors approved the initiation of a regular quarterly cash dividend to common shareholders. The initial quarterly dividend declared of $0.05 per common share will be payable on May 26, 2014 to shareholders of record on the close of business May 15, 2014.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	3 Months Ended
	Mar. 31, 2014
Accounting Policies [Abstract]	'
General	'
	General
	Intervest Bancshares Corporation (“IBC”) is the parent company of Intervest National Bank (“INB”). References in this report to “we,” “us” and “our” refer to these entities on a consolidated basis, unless otherwise specified. For a description of our business, see note 1 to the financial statements in our 2013 Annual Report on Form 10-K (“2013 10-K”). Our accounting and reporting policies conform to U.S. generally accepted accounting principles (GAAP) and general practices within the banking industry and are described in note 1 to the financial statements in our 2013 10-K, as updated by the information in this Form 10-Q.
Principles of Consolidation and Basis of Presentation	'
	Principles of Consolidation and Basis of Presentation
	The condensed consolidated financial statements (“financial statements”) in this report have not been audited except for information derived from our audited 2013 consolidated financial statements and notes thereto and should be read in conjunction with our 2013 10-K. Certain information and note disclosures normally included in financial statements prepared in accordance with GAAP have been condensed or omitted in this report pursuant to the rules and regulations of the Securities and Exchange Commission.
Use of Estimates	'
	Use of Estimates
	In preparing our financial statements, we are required to make estimates and assumptions that affect the reported amounts of assets, liabilities and disclosure of contingent liabilities as of the date of the financial statements, and revenues and expenses during the reporting periods. Actual results could differ from those estimates. Estimates that are particularly susceptible to significant change currently relate to the determination of our allowance for loan losses, valuation allowance for real estate losses, other than temporary impairment assessments of our security investments and the need for and amount of a valuation allowance for our deferred tax asset. These estimates involve a higher degree of complexity and subjectivity and may require assumptions about highly uncertain matters. Current market conditions increase the risk and complexity of the judgments in these estimates. In our opinion, all material adjustments necessary for a fair presentation of our financial condition and results of operations for the interim periods presented in this report have been made. These adjustments are of a normal recurring nature. All significant intercompany balances and transactions have been eliminated in consolidation. Our results of operations for the interim periods are not necessarily indicative of results that may be expected for the entire year or any other interim period.
Stock-Based Compensation	'
	Stock-Based Compensation
	We recognize the cost of our employee and director services received in exchange for awards of our equity instruments (which are in the form of restricted stock, stock options and cash-settled stock appreciation rights or “SARs”) that vest over time based on the grant-date fair value of the awards. The fair value of restricted stock grants is based on the closing market value of our common stock as reported on the Nasdaq Stock Market on the grant date. The fair value of options and SARs is estimated using the Black-Scholes option-pricing model based on various inputs and assumptions that are described in note 9. Compensation cost, or the grant-date fair value of the awards, related to equity awards is recognized on a straight-line basis over the requisite service period, which is normally the vesting period of the grants.
	For SARs only, fair value is re-measured at the end of each reporting period and amortized as compensation cost over the remaining requisite service period less amounts previously recognized. The SARs represent liability-classified awards that are remeasured to reflect their fair value at each reporting period. After the requisite service period is completed, the SAR’s fair value continues to be remeasured each reporting period until settlement and any increase/decrease in the fair value is immediately recognized as an increase/decrease to our reported stock compensation expense. Upon cash-settlement of a SAR, stock compensation expense is trued-up to equal the SAR’s intrinsic cash value on the date of settlement.
	Stock-based compensation associated with equity awards is recorded as stock compensation expense in the statement of earnings and a corresponding increase to stockholders’ equity as additional paid-in capital for amounts related to restricted stock and stock options, and corresponding increase to accrued stock compensation payable for amounts related to the SARs, which is reported as part of our “other liabilities” in our balance sheet.
	For any excess income tax benefit associated with the vesting of restricted common stock awards and the exercise of stock option awards (calculated as the difference between the fair market value of the stock at the vesting date versus the grant date in the case of stock awards and the difference between the fair market value of the stock at the exercise date versus the exercise price per share in the case of options, multiplied by our effective income tax rate) is recorded as decrease to our income taxes payable and an increase in stockholders’ equity as paid-in capital.
Recent Accounting Standards Update	'
	Recent Accounting Standards Update
	In February 2013, the FASB Issued ASU No. 2013-04, “Obligations Resulting from Joint and Several Liability Arrangements for Which the Total Amount of the Obligation Is Fixed at the Reporting Date”. ASU 2013-04 provides guidance for the recognition, measurement, and disclosure of obligations resulting from joint and several liability arrangements for obligations within the scope of this ASU. We adopted this ASU on January 1, 2014 and it had no impact on our financial statements.
	In July 2013, the FASB issued ASU 2013-11, “Presentation of an Unrecognized Tax Benefit When a Net Operating Loss Carryforward, a Similar Tax Loss, or a Tax Credit Carryforward Exists,” which among other things, requires an unrecognized tax benefit, or a portion of an unrecognized tax benefit, to be presented in the financial statements as a reduction to a deferred tax asset for a net operating loss carryforward, a similar tax loss, or a tax credit carryforward, except as denoted within the ASU. The amendments in this ASU are effective for fiscal years, and interim periods within those years, beginning after December 15, 2013. We adopted this ASU on January 1, 2014 and it had no impact on our financial statements.
	In January 2014, the FASB issued ASU 2014-04, “Receivables-Troubled Debt Restructurings by Creditors (Subtopic 310-40): Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure”, which is intended to clarify when a creditor should be considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan such that the loan should be derecognized and the real estate recognized. These amendments clarify that an in substance repossession or foreclosure occurs, and a creditor is considered to have received physical possession of residential real estate property collateralizing a consumer mortgage loan, upon either: (a) the creditor obtaining legal title to the residential real estate property upon completion of a foreclosure; or (b) the borrower conveying all interest in the residential real estate property to the creditor to satisfy that loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Additional disclosures are required. The amendments are effective for us beginning January 1, 2015.

Securities_Held_to_Maturity_an1

Securities Held to Maturity and Available for Sale (Tables)	3 Months Ended
	Mar. 31, 2014
Investments Debt And Equity Securities [Abstract]	'
Carrying Value (Amortized Cost) and Estimated Fair Value of Securities Held to Maturity	'
	The carrying value (amortized cost) and estimated fair value of securities held to maturity (“HTM”) are as follows:
	($ in thousands)		Number of		Amortized		Gross			Gross		Estimated		Wtd-Avg			Wtd-Avg		Wtd-Avg
			Securities		Cost		Unrealized			Unrealized		Fair		Yield			Expected		Remaining
							Gains			Losses		Value					Life		Maturity
	At March 31, 2014
	U.S. government agencies (1)			143	$	267,475	$	359		$	3,529	$	264,305		1	%		3.1 Yrs		3.8 Yrs
	Residential mortgage-backed (2)			63		78,419		310			675		78,054		1.87	%		4.4 Yrs		14.1 Yrs
	State and municipal			1		531		—			2		529		1.25	%		3.0 Yrs		3.0 Yrs
				207	$	346,425	$	669		$	4,206	$	342,888		1.2	%		3.4 Yrs		6.1 Yrs
	At December 31, 2013
	U.S. government agencies (1)			161	$	305,906	$	410		$	4,947	$	301,369		0.94	%		3.0 Yrs		3.8 Yrs
	Residential mortgage-backed (2)			57		77,500		130			1,017		76,613		1.79	%		4.3 Yrs		14.7 Yrs
	State and municipal			1		531		—			6		525		1.25	%		3.2 Yrs		3.3 Yrs
				219	$	383,937	$	540		$	5,970	$	378,507		1.11	%		3.3 Yrs		6.0 Yrs
	-1	Consist of debt obligations of U.S. government sponsored agencies (GSEs)—Federal Home Loan Bank (FHLB), Federal Farm Credit Bank (FFCB), Federal National Mortgage Association (FNMA) and Federal Home Loan Mortgage Corporation (FHLMC), which are federally chartered corporations privately owned by shareholders. GSE securities carry no explicit U.S. government guarantee of creditworthiness. Neither principal nor interest payments are guaranteed by the U.S. government nor do they constitute a debt or obligation of the U.S. government or any of its agencies or instrumentalities other than the applicable GSE. FNMA and FHLMC are under U.S. government conservatorship.
	-2	At March 31, 2014, the portfolio consisted of $12.8 million of Government National Mortgage Association (GNMA) residential pass-through certificates and $65.6 million of residential participation certificates issued by FNMA or FHLMC, compared to $13.6 million and $63.9 million, respectively, at December 31, 2013. The GNMA pass-through certificates are guaranteed as to the payment of principal and interest by the full faith and credit of the U.S. government while the FNMA and FHLMC certificates have an implied guarantee by such agency as to principal and interest payments. Included in this line item are investments in FNMA DUS mortgage-backed securities (of approximately $11 million at March 31, 2014 and $7.0 million at December 31, 2013) that are backed by eligible multifamily pools that typically contain one loan or single purpose entity.
Continuous Unrealized Loss Position	'
	The estimated fair values of HTM securities with gross unrealized losses segregated between securities that have been in a continuous unrealized loss position for less than twelve months at the respective dates and those that have been in a continuous unrealized loss position for twelve months or longer are summarized as follows:
					Less Than Twelve					Twelve Months or				Total
					Months					Longer
	($ in thousands)		Number		Estimated		Gross			Estimated		Gross		Estimated			Gross
			of		Fair		Unrealized			Fair		Unrealized		Fair			Unrealized
			Securities		Value		Losses			Value		Losses		Value			Losses
	At March 31, 2014
	U.S. government agencies			127	$	227,279	$	3,411		$	6,381	$	118	$	233,660		$	3,529
	Residential mortgage-backed			40		39,011		591			6,451		84		45,462			675
	State and municipal			1		529		2			—		—		529			2
				168	$	266,819	$	4,004		$	12,832	$	202	$	279,651		$	4,206
	At December 31, 2013
	U.S. government agencies			130	$	233,930	$	4,791		$	7,344	$	156	$	241,274		$	4,947
	Residential mortgage-backed			41		48,862		987			3,284		30		52,146			1,017
	State and municipal			1		525		6			—		—		525			6
				172	$	283,317	$	5,784		$	10,628	$	186	$	293,945		$	5,970
Summary of Carrying Value (Amortized Cost) and Fair Value of Securities Held to Maturity	'
	The following table is a summary of the carrying value (amortized cost) and estimated fair value of HTM securities at March 31, 2014, by remaining period to contractual maturity (ignoring earlier call dates, if any). The amounts reported in the table also did not consider the effects of possible prepayments or unscheduled repayments. Accordingly, actual maturities may differ from contractual maturities shown in the table.
	($ in thousands)		Amortized		Estimated		Wtd-Avg
			Cost		Fair Value		Yield
	Due in one year or less		$	8,339	$	8,377		1.32	%
	Due after one year through five years			237,125		234,698		0.96
	Due after five years through ten years			50,439		49,530		1.59
	Due after ten years			50,522		50,283		1.93
			$	346,425	$	342,888		1.2	%

Loans_Receivable_Tables

Loans Receivable (Tables)	3 Months Ended
	Mar. 31, 2014
Receivables [Abstract]	'
Major Classifications of Loans Receivable	'
	Major classifications of loans receivable are summarized as follows:
			At March 31, 2014					At December 31, 2013
	($ in thousands)		# of Loans		Amount			# of Loans		Amount
	Loans Secured By Real Estate:
	Commercial loans			406	$	862,100			394	$	838,766
	Multifamily loans			139		209,593			138		210,270
	One to four family loans			18		64,366			20		72,064
	Land loans			5		9,116			5		9,178
				568		1,145,175			557		1,130,278
	All Other Loans:
	Business loans			18		1,069			19		1,061
	Consumer loans			10		190			12		211
				28		1,259			31		1,272
	Loans receivable, gross			596		1,146,434			588		1,131,550
	Deferred loan fees					(4,203	)				(4,028	)
	Loans receivable, net of deferred fees					1,142,231					1,127,522
	Allowance for loan losses					(27,418	)				(27,833	)
	Loans receivable, net				$	1,114,813				$	1,099,689
Summary of Impaired Loans	'
	The tables below summarize certain information regarding our impaired loans as follows:
	($ in thousands)		Recorded Investment by State (1)																		Specific		Total		# of
																					Valuation		Unpaid		Loans
	At March 31, 2014		NY		FL			VA		GA			CT		OH		SD		Total		Allowance (2)		Principal (3)
	Type
	Retail		$	8,180	$	9,005		$	7,777	$	—		$	2,699	$	985	$	—	$	28,646	$	3,037	$	36,087		7
	Office Building			—		14,349			—		8,695			—		—		—		23,044		1,929		23,044		3
	Parking Lot			2,622		—			—		—			—		—		—		2,622		79		2,622		1
	Multifamily			844		3,118			—		—			—		—		—		3,962		617		3,962		3
	Land			—		—			—		—			—		—		1,590		1,590		48		1,590		1
	Totals		$	11,646	$	26,472		$	7,777	$	8,695		$	2,699	$	985	$	1,590	$	59,864	$	5,710	$	67,305		15
	($ in thousands)		Recorded Investment by State (1)																		Specific		Total		# of
																					Valuation		Unpaid		Loans
	At December 31, 2013		NY		FL			VA		GA			CT		OH		SD		Total		Allowance (2)		Principal (3)
	Type
	Retail		$	8,223	$	9,005		$	7,828	$	—		$	2,719	$	1,000	$	—	$	28,775	$	3,052	$	36,216		7
	Office Building			—		14,937			—		8,695			—		—		—		23,632		1,947		23,632		3
	Multifamily			—		3,128			—		—			—		—		—		3,128		594		3,128		2
	Land			—		—			—		—			—		—		1,625		1,625		500		1,625		1
	Totals		$	8,223	$	27,070		$	7,828	$	8,695		$	2,719	$	1,000	$	1,625	$	57,160	$	6,093	$	64,601		13
	-1	Represents unpaid principal less partial principal charge offs and interest received and applied as a reduction of principal in certain cases.
	-2	Represents a specific valuation allowance against the recorded investment, which is included as part of our overall allowance for loan losses. All impaired loans at the dates indicated in the table had a specific valuation allowance.
	-3	Represents contractual unpaid principal balance (shown for informational purposes only). The borrowers are obligated to pay such amounts. However, the ultimate collection by us of such amounts in this column is not assured.
Other Information Related to Impaired Loans	'
	Other information related to our impaired loans is summarized as follows:
			For the Quarter Ended March 31,
	($ in thousands)		2014		2013
	Average recorded investment in nonaccrual loans		$	36,464	$	43,705
	Total cash basis interest income recognized on nonaccrual loans			519		598
	Average recorded investment in accruing TDR loans			13,385		17,853
	Total interest income recognized on accruing TDR loans under modified terms			177		250
Age Analysis of Loan Portfolio by Segment	'
	Age analysis of our loan portfolio by segment at March 31, 2014 is summarized as follows:
	($ in thousands)		Total		Current			Past Due		Past Due			Past Due		Total
			Portfolio					31-59		60-89			90 or more		Past Due
								Days		Days			Days
	Accruing Loans:
	Commercial real estate		$	824,194	$	819,959		$	4,235	$	—		$	—	$	4,235
	Multifamily			208,749		202,057			6,692		—			—		6,692
	One to four family			64,366		64,366			—		—			—		—
	Land			9,116		9,116			—		—			—		—
	All other			1,259		1,259			—		—			—		—
	Total accruing loans			1,107,684		1,096,757			10,927		—			—		10,927
	Nonaccrual Loans (1):
	Commercial real estate			37,906		35,284			—		2,622			—		2,622
	Multifamily			844		—			—		—			844		844
	Total nonaccrual loans			38,750		35,284			—		2,622			844		3,466
	Total loans		$	1,146,434	$	1,132,041		$	10,927	$	2,622		$	844	$	14,393
	-1	The amount of nonaccrual loans in the current column included $32.6 million of TDRs for which payments were being made in accordance with their restructured terms, but the loans were maintained on nonaccrual status in accordance with regulatory guidance. The remaining portion was comprised of certain paying loans classified nonaccrual due to concerns regarding the borrowers’ ability to continue making payments. Interest income from loan payments received on loans in nonaccrual status is recognized on a cash basis, provided the remaining principal balance is deemed collectible.
	Age analysis of our loan portfolio by segment at December 31, 2013 is summarized as follows:
	($ in thousands)		Total		Current			Past Due		Past Due			Past Due		Total
			Portfolio					31-59		60-89			90 or more		Past Due
								Days		Days			Days
	Accruing Loans:
	Commercial real estate		$	802,863	$	796,980		$	1,796	$	—		$	4,087	$	5,883
	Multifamily			210,270		209,426			844		—			—		844
	One to four family			72,064		72,064			—		—			—		—
	Land			9,178		9,178			—		—			—		—
	All other			1,272		1,271			1		—			—		1
	Total accruing loans			1,095,647		1,088,919			2,641		—			4,087		6,728
	Nonaccrual Loans (1):
	Commercial real estate			35,903		35,903			—		—			—		—
	Total nonaccrual loans			35,903		35,903			—		—			—		—
	Total loans		$	1,131,550	$	1,124,822		$	2,641	$	—		$	4,087	$	6,728
	-1	The amount of nonaccrual loans in the current column included $33.2 million of TDRs for which payments were being made in accordance with their restructured terms, but the loans were maintained on nonaccrual status in accordance with regulatory guidance. The remaining portion was comprised of certain paying loans classified nonaccrual due to concerns regarding the borrowers’ ability to continue making payments. Interest income from loan payments received on loans in nonaccrual status is recognized on a cash basis, provided the remaining principal balance is deemed collectible.
Information Regarding Credit Quality of Loan Portfolio	'
	Information regarding the credit quality of the loan portfolio based on our internally assigned grades follows:
	($ in thousands)		Pass		Special			Substandard (1)		Total
					Mention
	At March 31, 2014
	Commercial real estate		$	797,257	$	3,251		$	61,592	$	862,100
	Multifamily			202,797		2,365			4,431		209,593
	One to four family			64,366		—			—		64,366
	Land			7,526		—			1,590		9,116
	All other			1,259		—			—		1,259
	Total loans		$	1,073,205	$	5,616		$	67,613	$	1,146,434
	Allocation of allowance for loan losses		$	20,773	$	166		$	6,479	$	27,418
	At December 31, 2013
	Commercial real estate		$	772,900	$	3,522		$	62,344	$	838,766
	Multifamily			204,298		2,369			3,603		210,270
	One to four family			72,064		—			—		72,064
	Land			7,553		—			1,625		9,178
	All other			1,272		—			—		1,272
	Total loans		$	1,058,087	$	5,891		$	67,572	$	1,131,550
	Allocation of allowance for loan losses		$	20,720	$	169		$	6,944	$	27,833
	-1	Substandard loans consisted of $38.7 million of nonaccrual loans, $12.9 million of accruing TDRs and $16.0 million of other performing loans at March 31, 2014, compared to $35.9 million of nonaccrual loans, $13.1 million of accruing TDRs and $18.6 million of other performing loans at December 31, 2013. At March 31, 2014 and December 31, 2013, we also had one accruing TDR for $0.4 million which was rated pass.
Geographic Distribution of Loan Portfolio	'
	The geographic distribution of the loan portfolio by state follows:
			At March 31, 2014					At December 31, 2013
	($ in thousands)		Amount		% of Total			Amount		% of Total
	New York		$	653,447		57	%	$	670,052		59.2	%
	Florida			331,674		28.9			321,812		28.4
	North Carolina			25,988		2.3			22,611		2
	Georgia			19,271		1.7			18,799		1.7
	New Jersey			15,521		1.4			15,650		1.4
	Kentucky			13,846		1.2			11,930		1.1
	Pennsylvania			13,370		1.2			16,898		1.5
	Virginia			13,240		1.2			11,491		1
	Connecticut			10,136		0.9			8,429		0.7
	South Carolina			9,167		0.8			9,223		0.8
	Massachusetts			6,087		0.5			—		—
	Tennessee			5,807		0.5			5,843		0.5
	Michigan			5,556		0.5			5,599		0.5
	Ohio			4,666		0.4			4,703		0.4
	West Virginia			4,500		0.4			—		—
	Utah			3,984		0.3			—		—
	Indiana			3,644		0.3			2,820		0.2
	All other states			6,530		0.5			5,690		0.5
			$	1,146,434		100	%	$	1,131,550		100	%
Distribution of TDRs by Accruing Versus Non-Accruing, by Segment and by Geographic	'
	The distribution of TDRs by accruing versus non-accruing, by loan type and by geographic distribution follows:
	($ in thousands)		At March 31, 2014		At December 31, 2013
	Performing - nonaccrual status		$	32,585	$	33,184
	Performing - accrual status			13,337		13,429
			$	45,922	$	46,613
	Commercial real estate		$	41,214	$	41,860
	Multifamily			3,118		3,128
	Land			1,590		1,625
			$	45,922	$	46,613
	New York		$	8,180	$	8,223
	Florida			26,472		27,070
	Georgia			8,695		8,695
	Ohio			985		1,000
	South Dakota			1,590		1,625
			$	45,922	$	46,613

Allowance_for_Loan_Losses_Tabl

Allowance for Loan Losses (Tables)	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Allowance for Loan Losses by Loan Type	'
	Activity in the allowance for loan losses by loan type for the periods indicated is as follows:
	($ in thousands)		Commercial			Multifamily			One to Four			Land			All Other		Total
			Real Estate						Family
	Quarter Ended March 31, 2014
	Balance at beginning of period		$	18,403		$	5,097		$	3,017		$	1,308		$	8	$	27,833
	Loan chargeoffs			—			—			—			—			—		—
	Loan recoveries			71			14			—			—			—		85
	Provision (credit) for loan losses			339			1			(385	)		(455	)		—		(500	)
	Balance at end of period		$	18,813		$	5,112		$	2,632		$	853		$	8	$	27,418
	Quarter ended March 31, 2013
	Balance at beginning of period		$	19,051		$	6,881		$	1,120		$	1,043		$	8	$	28,103
	Loan chargeoffs			(115	)		—			—			—			—		(115	)
	Loan recoveries (1)			62			677			—			483			—		1,222
	Provision (credit) for loan losses			(354	)		(1,941	)		1,851			(556	)		—		(1,000	)
	Balance at end of period		$	18,644		$	5,617		$	2,971		$	970		$	8	$	28,210
	-1	In the first quarter of 2013, INB entered into settlement agreements with respect to certain litigation INB had pursued in connection with foreclosure actions it had commenced in 2010 on two of its loans. INB commenced the actions to collect, in one case, insurance proceeds, which it contended had been improperly paid to various third parties, and in another case, damages due to alleged legal malpractice when the loan was originated. As a result of these settlements, INB received net proceeds totaling $2.6 million in the first quarter of 2013, which was recorded as $1.1 million of recoveries of prior loan charge offs and a $1.5 million recovery of prior real estate expenses associated with one of the loans and underlying collateral property.
Loans Receivable by Segment and Impairment Evaluation and Allowance for Loan Losses	'
	The following table sets forth the balances of our loans receivable by segment and impairment evaluation and the allowance for loan losses associated with such loans at March 31, 2014.
	($ in thousands)		Commercial			Multifamily			One to Four			Land			All Other		Total
			Real Estate						Family
	Loans:
	Individually evaluated for impairment		$	54,312		$	3,962		$	—		$	1,590		$	—	$	59,864
	Collectively evaluated for impairment			807,788			205,631			64,366			7,526			1,259		1,086,570
	Total loans		$	862,100		$	209,593		$	64,366		$	9,116		$	1,259	$	1,146,434
	Allowance for loan losses:
	Individually evaluated for impairment (1)		$	5,045		$	617		$	—		$	48		$	—	$	5,710
	Collectively evaluated for impairment			13,768			4,495			2,632			805			8		21,708
	Total allowance for loan losses		$	18,813		$	5,112		$	2,632		$	853		$	8	$	27,418
	-1	See note 3 to financial statements in this report.
	The following table sets forth the balances of our loans receivable by segment and impairment evaluation and the allowance for loan losses associated with such loans at December 31, 2013.
	($ in thousands)		Commercial			Multifamily			One to Four			Land			All Other		Total
			Real Estate						Family
	Loans:
	Individually evaluated for impairment		$	52,407		$	3,128		$	—		$	1,625		$	—	$	57,160
	Collectively evaluated for impairment			786,359			207,142			72,064			7,553			1,272		1,074,390
	Total loans		$	838,766		$	210,270		$	72,064		$	9,178		$	1,272	$	1,131,550
	Allowance for loan losses:
	Individually evaluated for impairment (1)		$	4,999		$	594		$	—		$	500		$	—	$	6,093
	Collectively evaluated for impairment			13,404			4,503			3,017			808			8		21,740
	Total allowance for loan losses		$	18,403		$	5,097		$	3,017		$	1,308		$	8	$	27,833
	-1	See note 3 to financial statements in this report.

Foreclosed_Real_Estate_and_Val1

Foreclosed Real Estate and Valuation Allowance for Real Estate Losses (Tables)	3 Months Ended
	Mar. 31, 2014
Banking And Thrift [Abstract]	'
Summary of Real Estate Acquired through Foreclosure by Property Type	'
	Real estate acquired through foreclosure by property type is summarized as follows:
			At March 31, 2014					At December 31, 2013
	($ in thousands)		# of Properties			Amount (1)		# of Properties		Amount (1)
	Commercial real estate			1		$	2,650		2	$	3,984
	Multifamily			1			6,685		1		6,685
	Real estate acquired through foreclosure			2		$	9,335		3	$	10,669
	-1	Reported net of any associated valuation allowance.
Summary of Activity in the Valuation Allowance for Real Estate Losses	'
	Activity in the valuation allowance for real estate losses is summarized as follows:
			Quarter Ended
			March 31,
	($ in thousands)		2014			2013
	Valuation allowance at beginning of period		$	2,017		$	5,339
	Chargeoffs			(824	)		—
	Provision for real estate losses			—			629
	Valuation allowance at end of period		$	1,193		$	5,968

Deposits_Tables

Deposits (Tables)	3 Months Ended
	Mar. 31, 2014
Banking And Thrift [Abstract]	'
Scheduled Maturities of Certificates of Deposits	'
	Scheduled maturities of certificates of deposit accounts (CDs) are as follows:
		At March 31, 2014					At December 31, 2013
	($ in thousands)	Amount		Wtd-Avg			Amount		Wtd-Avg
				Stated Rate					Stated Rate
	Within one year	$	324,311		1.96	%	$	307,122		1.97	%
	Over one to two years		131,082		1.7			167,323		1.92
	Over two to three years		215,603		1.96			170,956		1.92
	Over three to four years		90,665		2.31			106,700		2.5
	Over four years		149,815		2.04			129,678		2.06
		$	911,476		1.97	%	$	881,779		2.03	%

Subordinated_Debentures_Capita1

Subordinated Debentures - Capital Securities (Tables)	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Summary of Capital Securities Outstanding	'
	Capital Securities (commonly referred to as trust preferred securities) outstanding are summarized as follows:
		At March 31, 2014							At December 31, 2013
	($ in thousands)	Principal		Accrued		Interest			Principal		Accrued		Interest
				Interest		Rate					Interest		Rate
				Payable							Payable
	Capital Securities II - debentures due September 17, 2033	$	15,464	$	20		3.18	%	$	15,464	$	275		3.19	%
	Capital Securities III - debentures due March 17, 2034		15,464		20		3.02	%		15,464		261		3.03	%
	Capital Securities IV - debentures due September 20, 2034		15,464		19		2.63	%		15,464		223		2.65	%
	Capital Securities V - debentures due December 15, 2036		10,310		8		1.88	%		10,310		109		1.89	%
		$	56,702	$	67				$	56,702	$	868

Common_Stock_Warrant_and_Equit1

Common Stock Warrant and Equity Incentive Plans (Tables)	3 Months Ended
	Mar. 31, 2014
Text Block [Abstract]	'
Summary of Selected Information Regarding Restricted Common Stock Awards made Under Plan	'
	A summary of outstanding common stock options and warrant and related information follows:
			Exercise Price Per Warrant/Option																					Wtd-Avg.
																								Exercise
	($ in thousands, except per share amounts)		$5.42 (1)			$17.10			$7.50			$4.02			$3.00			$2.55			Total			Price
	Outstanding at December 31, 2013			691,882			110,640			113,990			57,400			32,400			35,133			1,041,445		$	6.64
	Forfeited/expired (2)			—			(300	)		(300	)		(300	)		(300	)		(200	)		(1,400	)	$	7.14
	Options exercised			—			—			—			(900	)		(4,600	)		(5,067	)		(10,567	)	$	2.87
	Outstanding at March 31, 2014			691,882			110,340			113,690			56,200			27,500			29,866			1,029,478		$	6.68
	Expiration date			12/23/18			12/13/17			12/11/18			12/10/19			12/9/20			12/8/21
	Vested and exercisable (3)			100	%		100	%		100	%		100	%		100	%		67	%		99	%
	Wtd-avg contractual remaining term (in years)			4.7			3.7			4.7			5.7			6.7			7.7			4.9
	Intrinsic value at March 31, 2014 (4)		$	1,405		$	—		$	—		$	193		$	122		$	146		$	1,866
	-1	The U.S. Department of the Treasury, in connection with IBC’s prior participation in the Capital Purchase Program, owns a warrant to purchase 691,882 shares of IBC’s common stock at an exercise price of $5.42 per share.
	-2	Represent options forfeited or expired unexercised.
	-3	The $2.55 options further vest and become 100% exercisable on December 8, 2014. Full vesting may occur earlier upon the occurrence of certain events as defined in the option agreement.
	-4	Intrinsic value was calculated using the closing price of the common stock on March 31, 2014 of $7.45.
Summary of Outstanding Common Stock Warrant and Options	'
	A summary of selected information regarding awards of restricted common stock during the periods in this report follows:
	($ in thousands, except per share amounts)
	Grant date of award			1/23/14			1/24/13
	Total restricted shares of stock awarded (1)			92,000			330,700
	Grant date per share fair value (2)		$	7.65		$	4.5
	Total estimated fair value of award		$	703,800		$	1,488,150
	Awards scheduled to vest as follows:
	Jan-14			—			49,566
	Jan-15			30,664			170,888
	Jan-16			30,664			110,246
	Jan-17			30,672			—
				92,000			330,700
	-1	For 2014, awards were as follows: a total of 12,000 shares to five executive officers and a total of 80,000 shares to eight non-employee directors (vesting in three equal installments, with one third on each of the next three anniversary dates of the grant).
	For 2013, awards were as follows: a total of 182,000 shares to five executive officers (vesting in two installments, with two thirds vesting on the second anniversary of the grant and the remaining one third on the third anniversary of the grant); a total of 80,000 shares to eight non-employee directors and 68,700 shares to other officers and employees (vesting in three equal installments, with one third on each of the next three anniversary dates of the grant).
	-2	Fair value of each award was based on the closing market price of IBC’s common stock on the grant date.
Summary of Activity in IBCs Restricted Class A Common Stock	'
	A summary of outstanding restricted common stock and related information follows:
																		Wtd-Avg.
			Price Per Share															Price
			$2.90			$4.50			$7.21			$7.65			Total			Per Share
	Outstanding at December 31, 2013			158,317			279,500			135,500			—			573,317		$	4.7
	Shares vested and no longer restricted			(101,035	)		(47,664	)		(75,417	)		—			(224,116	)	$	4.69
	Shares granted			—			—			—			92,000			92,000		$	7.65
	Outstanding at March 31, 2014 (1) (2)			57,282			231,836			60,083			92,000			441,201		$	5.32
	-1	All outstanding shares of restricted common stock at March 31, 2014 were unvested and subject to forfeiture.
	Shares issued at $2.90 vest: 57,282 on January 19, 2015.
	Shares issued at $4.50 vest: 138,664 on January 24, 2015; 93,172 on January 24, 2016.
	Shares issued at $7.21 vest: 14,584 on January 19, 2015; 30,333 on January 24, 2015; 15,166 on January 24, 2016.
	Shares issued at $7.65 vest: 30,664 on January 23, 2015; 30,664 on January 23, 2016; 30,672 on January 23, 2017.
	-2	Vesting is subject to the grantee’s continued employment with us or, in the case of non-employee directors, the grantee’s continued service as our director on the vesting dates. All of the awards are subject to accelerated vesting upon the death or disability of the grantee or upon a change in control of IBC, as defined in the restricted stock agreements. The record holder of IBC’s restricted shares of common stock possesses all the rights of a holder of our common stock, including the right to receive dividends on the shares when declared and to vote the restricted shares. The restricted shares may not be sold, transferred, pledged, assigned, encumbered, or otherwise alienated or hypothecated until they become fully vested and transferable in accordance with the agreements.

Earnings_Per_Common_Share_Tabl

Earnings Per Common Share (Tables)	3 Months Ended
	Mar. 31, 2014
Earnings Per Share [Abstract]	'
Summary of Basic and Diluted Earnings Per Common Share	'
	Net earnings applicable to common stockholders and the weighted-average number of shares used for basic and diluted earnings per common share computations are summarized in the table that follows:
			Quarter Ended
			March 31,
			2014		2013
	Basic Earnings Per Common Share:
	Net earnings available to common stockholders		$	3,842,000	$	3,429,000
	Weighted-Average number of common shares outstanding			21,991,451		21,832,200
	Basic Earnings Per Common Share		$	0.17	$	0.16
	Diluted Earnings Per Common Share:
	Net earnings applicable to common stockholders		$	3,842,000	$	3,429,000
	Weighted-Average number of common shares outstanding:
	Common shares outstanding			21,991,451		21,832,200
	Potential dilutive shares resulting from exercise of			229,050		22,255
	warrants/options (1)
	Total average number of common shares outstanding used for dilution			22,220,501		21,854,455
	Diluted Earnings Per Common Share		$	0.17	$	0.16
	-1	All outstanding options/warrants to purchase shares of our common stock were considered for the Diluted EPS computations and only those that were dilutive (as determined by using the treasury stock method prescribed by GAAP) were included in the computations above. In the 2014 and 2013 periods, 110,340 and 928,112 of options/warrants to purchase common stock, respectively, were not dilutive because the exercise price of each was above the average market price of our common stock during these periods.

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2014
Fair Value Disclosures [Abstract]	'
Assets Measured at Fair Value on a Nonrecurring Basis	'
	The following tables provide information regarding our assets measured at fair value on a nonrecurring basis.
			Outstanding Carrying Value
			At Mar 31, 2014			At Dec 31, 2013
	($ in thousands)		Level 3			Level 3
	Impaired loans (1) :
	Commercial real estate		$	54,312		$	52,407
	Multifamily			3,962			3,128
	Land			1,590			1,625
	Total impaired loans			59,864			57,160
	Foreclosed real estate			9,335			10,669
									Total Losses (Gains) (2)
			Accumulated Losses on						Quarter Ended
			Outstanding Balance						March 31,
	($ in thousands)		At Mar			At Dec			2014			2013
			31, 2014			31, 2013
	Impaired loans:
	Commercial real estate		$	11,498		$	11,522		$	(24	)	$	389
	Multifamily			617			594			23			(423	)
	Land			48			500			(452	)		(14	)
	Total impaired loans			12,163			12,616			(453	)		(48	)
	Impaired securities			—			—			—			366
	Foreclosed real estate			1,193			2,017			(72	)		629
	-1	Outstanding carrying value excludes a specific valuation allowance. See note 4 to the financial statements in this report.
	-2	Represents total losses or (gains) recognized on all assets measured at fair value on a nonrecurring basis during the period indicated. The losses or (gains) for impaired loans represent the change (before chargeoffs and recoveries) during the period in the corresponding specific valuation allowance, while the losses (gains) for foreclosed real estate represent writedowns in carrying values subsequent to foreclosure (recorded as provisions for real estate losses) adjusted for any recoveries of prior write downs and (gains) or losses from the transfer/sale of properties during the period. The losses on securities represent the total of other than temporary impairment charges, which are recorded as component of noninterest income.
Change in Assets Measured at Fair Value on a Nonrecurring Basis	'
	The following table presents information regarding the change in assets measured at fair value on a nonrecurring basis for the periods indicated.
	($ in thousands)		Impaired			Impaired			Foreclosed
			Securities			Loans			Real Estate
	Quarter Ended March 31, 2014
	Balance at beginning of period		$	—		$	57,160		$	10,669
	Net new impaired loans			—			3,466			—
	Principal repayments/sales			—			(762	)		(1,406	)
	Gain from sales			—			—			72
	Balance at end of period		$	—		$	59,864		$	9,335
	Quarter Ended March 31, 2013
	Balance at beginning of period		$	3,721		$	65,973		$	15,923
	Net new impaired loans			—			1,485			—
	Principal repayments/sales			(63	)		(9,467	)		—
	Chargeoffs			—			(115	)		—
	Transferred to foreclosed real estate			—			(3,040	)		3,040
	Other than temporary impairment writedowns			(366	)		—			—
	Writedowns of carrying value subsequent to foreclosure			—			—			(629	)
	Balance at end of period		$	3,292		$	54,836		$	18,334
Carrying and Estimated Fair Values of Financial Instruments	'
	The carrying and estimated fair values of our financial instruments are as follows:
			At March 31, 2014						At December 31, 2013
	($ in thousands)		Carrying			Fair			Carrying			Fair
			Value			Value			Value			Value
	Financial Assets:
	Cash and cash equivalents (1)		$	79,157		$	79,157		$	24,700		$	24,700
	Time deposits with banks (1)			5,370			5,370			5,370			5,370
	Securities available for sale, net (1)			980			980			965			965
	Securities held to maturity, net (2)			346,425			342,888			383,937			378,507
	FRB and FHLB stock (3)			8,260			8,260			8,244			8,244
	Loans receivable, net (3)			1,114,813			1,119,116			1,099,689			1,100,858
	Accrued interest receivable (3)			4,630			4,630			4,861			4,861
	Loan fees receivable (3)			2,266			1,788			2,298			1,808
	Total Financial Assets		$	1,561,901		$	1,562,189		$	1,530,064		$	1,525,313
	Financial Liabilities:
	Deposits (3)		$	1,303,972		$	1,316,092		$	1,282,232		$	1,294,690
	Borrowed funds plus accrued interest payable (3)			56,769			56,460			57,570			57,260
	Accrued interest payable on deposits (3)			1,099			1,099			1,508			1,508
	Commitments to lend (3)			450			450			408			408
	Total Financial Liabilities		$	1,362,290		$	1,374,101		$	1,341,718		$	1,353,866
	Net Financial Assets		$	199,611		$	188,088		$	188,346		$	171,447
	-1	We consider these fair value measurements to be Level 1.
	-2	We consider these fair value measurements to be Level 2.
	-3	We consider these fair value measurements to be Level 3.

Securities_Held_to_Maturity_an2

Securities Held to Maturity and Available for Sale - Carrying Value (Amortized Cost) and Estimated Fair Value of Securities Held to Maturity (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Security	Security
Schedule of Held-to-maturity Securities [Line Items]	'	'
Number of Securities	207	219
Amortized Cost	$346,425	$383,937
Gross Unrealized Gains	669	540
Gross Unrealized Losses	4,206	5,970
Estimated Fair Value	342,888	378,507
Wtd-Avg Yield	1.20%	1.11%
Wtd-Avg Expected Life	'3 years 4 months 24 days	'3 years 3 months 18 days
Wtd-Avg Remaining Maturity	'6 years 1 month 6 days	'6 years
U.S. government agencies [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Number of Securities	143	161
Amortized Cost	267,475	305,906
Gross Unrealized Gains	359	410
Gross Unrealized Losses	3,529	4,947
Estimated Fair Value	264,305	301,369
Wtd-Avg Yield	1.00%	0.94%
Wtd-Avg Expected Life	'3 years 1 month 6 days	'3 years
Wtd-Avg Remaining Maturity	'3 years 9 months 18 days	'3 years 9 months 18 days
Residential mortgage-backed [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Number of Securities	63	57
Amortized Cost	78,419	77,500
Gross Unrealized Gains	310	130
Gross Unrealized Losses	675	1,017
Estimated Fair Value	78,054	76,613
Wtd-Avg Yield	1.87%	1.79%
Wtd-Avg Expected Life	'4 years 4 months 24 days	'4 years 3 months 18 days
Wtd-Avg Remaining Maturity	'14 years 1 month 6 days	'14 years 8 months 12 days
State and municipal [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Number of Securities	1	1
Amortized Cost	531	531
Gross Unrealized Gains	'	'
Gross Unrealized Losses	2	6
Estimated Fair Value	$529	$525
Wtd-Avg Yield	1.25%	1.25%
Wtd-Avg Expected Life	'3 years	'3 years 2 months 12 days
Wtd-Avg Remaining Maturity	'3 years	'3 years 3 months 18 days

Securities_Held_to_Maturity_an3

Securities Held to Maturity and Available for Sale - Carrying Value (Amortized Cost) and Estimated Fair Value of Securities Held to Maturity (Parenthetical) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized Cost	$346,425	$383,937
Government National Mortgage Association [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized Cost	12,800	13,600
Federal National Mortgage Association [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized Cost	65,600	63,900
Federal National Mortgage Association Delegated Underwriting and Servicing [Member]	'	'
Schedule of Held-to-maturity Securities [Line Items]	'	'
Amortized Cost	$11,000	$7,000

Securities_Held_to_Maturity_an4

Securities Held to Maturity and Available for Sale - Continuous Unrealized Loss Position (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Security	Security
Long Term Debt Maturity [Line Items]	'	'
Number of Securities	168	172
Less Than Twelve Months, Estimated Fair Value	$266,819	$283,317
Less Than Twelve Months, Gross Unrealized Losses	4,004	5,784
Twelve Months or Longer, Estimated Fair Value	12,832	10,628
Twelve Months or Longer, Gross Unrealized Losses	202	186
Total Estimated Fair Value	279,651	293,945
Total Gross Unrealized Losses	4,206	5,970
U.S. government agencies [Member]	'	'
Long Term Debt Maturity [Line Items]	'	'
Number of Securities	127	130
Less Than Twelve Months, Estimated Fair Value	227,279	233,930
Less Than Twelve Months, Gross Unrealized Losses	3,411	4,791
Twelve Months or Longer, Estimated Fair Value	6,381	7,344
Twelve Months or Longer, Gross Unrealized Losses	118	156
Total Estimated Fair Value	233,660	241,274
Total Gross Unrealized Losses	3,529	4,947
Residential mortgage-backed [Member]	'	'
Long Term Debt Maturity [Line Items]	'	'
Number of Securities	40	41
Less Than Twelve Months, Estimated Fair Value	39,011	48,862
Less Than Twelve Months, Gross Unrealized Losses	591	987
Twelve Months or Longer, Estimated Fair Value	6,451	3,284
Twelve Months or Longer, Gross Unrealized Losses	84	30
Total Estimated Fair Value	45,462	52,146
Total Gross Unrealized Losses	675	1,017
State and municipal [Member]	'	'
Long Term Debt Maturity [Line Items]	'	'
Number of Securities	1	1
Less Than Twelve Months, Estimated Fair Value	529	525
Less Than Twelve Months, Gross Unrealized Losses	2	6
Twelve Months or Longer, Estimated Fair Value	'	'
Twelve Months or Longer, Gross Unrealized Losses	'	'
Total Estimated Fair Value	529	525
Total Gross Unrealized Losses	$2	$6

Securities_Held_to_Maturity_an5

Securities Held to Maturity and Available for Sale - Summary of Carrying Value (Amortized Cost) and Fair Value of Securities Held to Maturity (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Investments Debt And Equity Securities [Abstract]	'	'
Due in one year or less, Amortized Cost	$8,339	'
Due in one year or less, Estimated Fair Value	8,377	'
Due in one year or less, Wtd-Avg Yield	1.32%	'
Due after one year through five years, Amortized Cost	237,125	'
Due after one year through five years, Estimated Fair Value	234,698	'
Due after one year through five years, Wtd-Avg Yield	0.96%	'
Due after five years through ten years, Amortized Cost	50,439	'
Due after five years through ten years, Estimated Fair Value	49,530	'
Due after five years through ten years, Wtd-Avg Yield	1.59%	'
Due after ten years, Amortized Cost	50,522	'
Due after ten years, Estimated Fair Value	50,283	'
Due after ten years, Wtd-Avg Yield	1.93%	'
Securities held to maturity, Total Amortized Cost	346,425	'
Estimated Fair Value	$342,888	$378,507
Securities held to maturity, Wtd-Avg Yield	1.20%	1.11%

Securities_Held_to_Maturity_an6

Securities Held to Maturity and Available for Sale - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, except Share data, unless otherwise specified
Investments Debt And Equity Securities [Abstract]	'	'
Securities available for sale, at estimated fair value	$980	$965
Shares owned in an intermediate bond fund	92,364	91,700

Loans_Receivable_Major_Classif

Loans Receivable - Major Classification of Loans Receivable (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified	SecurityLoan	SecurityLoan
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	596,000	588,000	'	'
Loans receivable, gross, Amount	$1,146,434	$1,131,550	'	'
Deferred loan fees	-4,203	-4,028	'	'
Loans receivable, net of deferred fees	1,142,231	1,127,522	'	'
Allowance for loan losses	-27,418	-27,833	-28,210	-28,103
Loans receivable, net	1,114,813	1,099,689	'	'
Loans Secured by Real Estate [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	568,000	557,000	'	'
Loans receivable, gross, Amount	1,145,175	1,130,278	'	'
All Other Loans [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	28,000	31,000	'	'
Loans receivable, gross, Amount	1,259	1,272	'	'
Commercial Real Estate [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Allowance for loan losses	-18,813	-18,403	-18,644	-19,051
Commercial Real Estate [Member] | Loans Secured by Real Estate [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	406,000	394,000	'	'
Loans receivable, gross, Amount	862,100	838,766	'	'
Multifamily [Member] | Loans Secured by Real Estate [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	139,000	138,000	'	'
Loans receivable, gross, Amount	209,593	210,270	'	'
One to Four Family [Member] | Loans Secured by Real Estate [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	18,000	20,000	'	'
Loans receivable, gross, Amount	64,366	72,064	'	'
Land Loans [Member] | Loans Secured by Real Estate [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	5,000	5,000	'	'
Loans receivable, gross, Amount	9,116	9,178	'	'
Business Loans [Member] | All Other Loans [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	18,000	19,000	'	'
Loans receivable, gross, Amount	1,069	1,061	'	'
Consumer Loans [Member] | All Other Loans [Member]	'	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'	'
Loans receivable, gross, # of Loans	10,000	12,000	'	'
Loans receivable, gross, Amount	$190	$211	'	'

Loans_Receivable_Additional_In

Loans Receivable - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
	SecurityLoan	SecurityLoan
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
90 days past due and still accruing interest loan	$844,000	$4,087,000
Troubled debt restructured loans	45,922,000	46,613,000
Performing and accruing loans classified as impaired	7,800,000	7,800,000
Performing loans	1	1
Accruing Loans [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Number of loans, 90 days past due and still accruing	0	3
90 days past due and still accruing interest loan	'	4,100,000
Troubled debt restructured loans	12,900,000	13,100,000
Troubled debt restructured loans	13,300,000	13,500,000
Nonaccrual Loans [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total loans	38,700,000	35,900,000
Troubled debt restructured loans	38,700,000	35,900,000
Non-accrual Status [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Troubled debt restructured loans	$32,600,000	$33,200,000

Loans_Receivable_Summary_of_Im

Loans Receivable - Summary of Impaired Loans (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	SecurityLoan	SecurityLoan
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	$59,864	$57,160
Specific Valuation Allowance	5,710	6,093
Total Unpaid Principal	67,305	64,601
# of Loans	15	13
New York [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	11,646	8,223
Florida [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	26,472	27,070
Virginia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	7,777	7,828
Georgia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	8,695	8,695
Connecticut [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	2,699	2,719
Ohio [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	985	1,000
South Dakota [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	1,590	1,625
Retail [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	28,646	28,775
Specific Valuation Allowance	3,037	3,052
Total Unpaid Principal	36,087	36,216
# of Loans	7	7
Retail [Member] | New York [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	8,180	8,223
Retail [Member] | Florida [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	9,005	9,005
Retail [Member] | Virginia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	7,777	7,828
Retail [Member] | Georgia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Retail [Member] | Connecticut [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	2,699	2,719
Retail [Member] | Ohio [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	985	1,000
Retail [Member] | South Dakota [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Office Building [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	23,044	23,632
Specific Valuation Allowance	1,929	1,947
Total Unpaid Principal	23,044	23,632
# of Loans	3	3
Office Building [Member] | New York [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Office Building [Member] | Florida [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	14,349	14,937
Office Building [Member] | Virginia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Office Building [Member] | Georgia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	8,695	8,695
Office Building [Member] | Connecticut [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Office Building [Member] | Ohio [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Office Building [Member] | South Dakota [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Parking Lot [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	2,622	'
Specific Valuation Allowance	79	'
Total Unpaid Principal	2,622	'
# of Loans	1	'
Parking Lot [Member] | New York [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	2,622	'
Parking Lot [Member] | Florida [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Parking Lot [Member] | Virginia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Parking Lot [Member] | Georgia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Parking Lot [Member] | Connecticut [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Parking Lot [Member] | Ohio [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Parking Lot [Member] | South Dakota [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Multifamily [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	3,962	3,128
Specific Valuation Allowance	617	594
Total Unpaid Principal	3,962	3,128
# of Loans	3	2
Multifamily [Member] | New York [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	844	'
Multifamily [Member] | Florida [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	3,118	3,128
Multifamily [Member] | Virginia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Multifamily [Member] | Georgia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Multifamily [Member] | Connecticut [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Multifamily [Member] | Ohio [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Multifamily [Member] | South Dakota [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	1,590	1,625
Specific Valuation Allowance	48	500
Total Unpaid Principal	1,590	1,625
# of Loans	1	1
Land [Member] | New York [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member] | Florida [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member] | Virginia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member] | Georgia [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member] | Connecticut [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member] | Ohio [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	'	'
Land [Member] | South Dakota [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Recorded Investment	$1,590	$1,625

Loans_Receivable_Other_Informa

Loans Receivable - Other Information Related to Impaired Loans (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Nonaccrual Loans [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Average recorded investment in accruing TDR loans	$36,464	$43,705
Total cash basis interest income recognized on nonaccrual loans	519	598
TDR Loans [Member]	'	'
Financing Receivable, Modifications [Line Items]	'	'
Average recorded investment in accruing TDR loans	13,385	17,853
Total interest income recognized on accruing TDR loans under modified terms	$177	$250

Loans_Receivable_Age_Analysis_

Loans Receivable - Age Analysis of Loan Portfolio by Segment (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	$1,146,434	$1,131,550
Current	1,132,041	1,124,822
Past Due 31-59 Days	10,927	2,641
Past Due 60-89 Days	2,622	'
Past Due 90 or more Days	844	4,087
Total Past Due	14,393	6,728
Accruing Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	1,107,684	1,095,647
Current	1,096,757	1,088,919
Past Due 31-59 Days	10,927	2,641
Past Due 60-89 Days	'	'
Past Due 90 or more Days	'	4,087
Total Past Due	10,927	6,728
Nonaccrual Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	38,750	35,903
Current	35,284	35,903
Past Due 31-59 Days	'	'
Past Due 60-89 Days	2,622	'
Past Due 90 or more Days	844	'
Total Past Due	3,466	'
Commercial Real Estate [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	862,100	838,766
Commercial Real Estate [Member] | Accruing Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	824,194	802,863
Current	819,959	796,980
Past Due 31-59 Days	4,235	1,796
Past Due 60-89 Days	'	'
Past Due 90 or more Days	'	4,087
Total Past Due	4,235	5,883
Commercial Real Estate [Member] | Nonaccrual Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	37,906	35,903
Current	35,284	35,903
Past Due 31-59 Days	'	'
Past Due 60-89 Days	2,622	'
Past Due 90 or more Days	'	'
Total Past Due	2,622	'
Multifamily [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	209,593	210,270
Multifamily [Member] | Accruing Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	208,749	210,270
Current	202,057	209,426
Past Due 31-59 Days	6,692	844
Past Due 60-89 Days	'	'
Past Due 90 or more Days	'	'
Total Past Due	6,692	844
Multifamily [Member] | Nonaccrual Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	844	'
Current	'	'
Past Due 31-59 Days	'	'
Past Due 60-89 Days	'	'
Past Due 90 or more Days	844	'
Total Past Due	844	'
One to Four Family [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	64,366	72,064
One to Four Family [Member] | Accruing Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	64,366	72,064
Current	64,366	72,064
Past Due 31-59 Days	'	'
Past Due 60-89 Days	'	'
Past Due 90 or more Days	'	'
Total Past Due	'	'
Land [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	9,116	9,178
Land [Member] | Accruing Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	9,116	9,178
Current	9,116	9,178
Past Due 31-59 Days	'	'
Past Due 60-89 Days	'	'
Past Due 90 or more Days	'	'
Total Past Due	'	'
All Other [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	1,259	1,272
All Other [Member] | Accruing Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Total Portfolio	1,259	1,272
Current	1,259	1,271
Past Due 31-59 Days	'	1
Past Due 60-89 Days	'	'
Past Due 90 or more Days	'	'
Total Past Due	'	$1

Loans_Receivable_Age_Analysis_1

Loans Receivable - Age Analysis of Loan Portfolio by Segment (Parenthetical) (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Mortgage Loans on Real Estate [Line Items]	'	'
Current	$1,132,041	$1,124,822
Nonaccrual Loans [Member]	'	'
Mortgage Loans on Real Estate [Line Items]	'	'
Current	$32,600	$33,200

Loans_Receivable_Information_R

Loans Receivable - Information Regarding Credit Quality of Loan Portfolio (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	$1,146,434	$1,131,550
Allocation of allowance for loan losses	27,418	27,833
Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	862,100	838,766
Multifamily [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	209,593	210,270
One to Four Family [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	64,366	72,064
Land [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	9,116	9,178
All Other [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	1,259	1,272
Pass [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	1,073,205	1,058,087
Allocation of allowance for loan losses	20,773	20,720
Pass [Member] | Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	797,257	772,900
Pass [Member] | Multifamily [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	202,797	204,298
Pass [Member] | One to Four Family [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	64,366	72,064
Pass [Member] | Land [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	7,526	7,553
Pass [Member] | All Other [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	1,259	1,272
Special Mention [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	5,616	5,891
Allocation of allowance for loan losses	166	169
Special Mention [Member] | Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	3,251	3,522
Special Mention [Member] | Multifamily [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	2,365	2,369
Special Mention [Member] | One to Four Family [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	'	'
Special Mention [Member] | Land [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	'	'
Special Mention [Member] | All Other [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	'	'
Substandard [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	67,613	67,572
Allocation of allowance for loan losses	6,479	6,944
Substandard [Member] | Commercial Real Estate [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	61,592	62,344
Substandard [Member] | Multifamily [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	4,431	3,603
Substandard [Member] | One to Four Family [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	'	'
Substandard [Member] | Land [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	1,590	1,625
Substandard [Member] | All Other [Member]	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'
Total loans	'	'

Loans_Receivable_Information_R1

Loans Receivable - Information Regarding Credit Quality of Loan Portfolio (Parenthetical) (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	Security_Loan	SecurityLoan	Security_Loan
Financing Receivable, Recorded Investment [Line Items]	'	'	'
Total Financing Receivable by TDRs	$45,922	'	$46,613
Number of rated pass accruing TDR	1	1	1
Nonaccrual Loans [Member]	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'
Total Financing Receivable by TDRs	38,700	'	35,900
Accruing Loans [Member]	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'
Total Financing Receivable by TDRs	12,900	'	13,100
All Other [Member]	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'
Total Financing Receivable by TDRs	16,000	'	18,600
Pass [Member] | Accruing Loans One [Member]	'	'	'
Financing Receivable, Recorded Investment [Line Items]	'	'	'
Total Financing Receivable by TDRs	$400	'	$400

Loans_Receivable_Geographic_Di

Loans Receivable - Geographic Distribution of Loan Portfolio (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	$1,146,434	$1,131,550
Total Loan Receivable, % of Total	100.00%	100.00%
New York [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	653,447	670,052
Total Loan Receivable, % of Total	57.00%	59.20%
Florida [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	331,674	321,812
Total Loan Receivable, % of Total	28.90%	28.40%
North Carolina [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	25,988	22,611
Total Loan Receivable, % of Total	2.30%	2.00%
Georgia [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	19,271	18,799
Total Loan Receivable, % of Total	1.70%	1.70%
New Jersey [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	15,521	15,650
Total Loan Receivable, % of Total	1.40%	1.40%
Kentucky [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	13,846	11,930
Total Loan Receivable, % of Total	1.20%	1.10%
Pennsylvania [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	13,370	16,898
Total Loan Receivable, % of Total	1.20%	1.50%
Virginia [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	13,240	11,491
Total Loan Receivable, % of Total	1.20%	1.00%
Connecticut [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	10,136	8,429
Total Loan Receivable, % of Total	0.90%	0.70%
South Carolina [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	9,167	9,223
Total Loan Receivable, % of Total	0.80%	0.80%
MASSACHUSETTS	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	6,087	'
Total Loan Receivable, % of Total	0.50%	'
Tennessee [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	5,807	5,843
Total Loan Receivable, % of Total	0.50%	0.50%
Michigan [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	5,556	5,599
Total Loan Receivable, % of Total	0.50%	0.50%
Ohio [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	4,666	4,703
Total Loan Receivable, % of Total	0.40%	0.40%
WEST VIRGINIA	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	4,500	'
Total Loan Receivable, % of Total	0.40%	'
UTAH	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	3,984	'
Total Loan Receivable, % of Total	0.30%	'
Indiana [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	3,644	2,820
Total Loan Receivable, % of Total	0.30%	0.20%
All Other States [Member]	'	'
Noncancelable Obligations Future Minimum Payments Due [Line Items]	'	'
Total loans	$6,530	$5,690
Total Loan Receivable, % of Total	0.50%	0.50%

Loans_Receivable_Distribution_

Loans Receivable - Distribution of TDRs by Accruing Versus Non-Accruing, by Segment and by Geographic (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	$45,922	$46,613
Total Financing Receivable by TDRs	45,922	46,613
Total Financing Receivable by TDRs	45,922	46,613
New York [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	8,180	8,223
Total Financing Receivable by TDRs	8,180	8,223
Total Financing Receivable by TDRs	8,180	8,223
Florida [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	26,472	27,070
Total Financing Receivable by TDRs	26,472	27,070
Total Financing Receivable by TDRs	26,472	27,070
Georgia [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	8,695	8,695
Total Financing Receivable by TDRs	8,695	8,695
Total Financing Receivable by TDRs	8,695	8,695
Ohio [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	985	1,000
Total Financing Receivable by TDRs	985	1,000
Total Financing Receivable by TDRs	985	1,000
SD [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	1,590	1,625
Total Financing Receivable by TDRs	1,590	1,625
Total Financing Receivable by TDRs	1,590	1,625
Commercial Real Estate [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	41,214	41,860
Total Financing Receivable by TDRs	41,214	41,860
Total Financing Receivable by TDRs	41,214	41,860
Multifamily [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	3,118	3,128
Total Financing Receivable by TDRs	3,118	3,128
Total Financing Receivable by TDRs	3,118	3,128
Land [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	1,590	1,625
Total Financing Receivable by TDRs	1,590	1,625
Total Financing Receivable by TDRs	1,590	1,625
Non-accrual Status [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	32,600	33,200
Total Financing Receivable by TDRs	32,600	33,200
Total Financing Receivable by TDRs	32,600	33,200
Performing [Member] | Non-accrual Status [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	32,585	33,184
Total Financing Receivable by TDRs	32,585	33,184
Total Financing Receivable by TDRs	32,585	33,184
Performing [Member] | Accrual Status [Member]	'	'
Financing Receivable Modifications Number Of Contracts [Line Items]	'	'
Total Financing Receivable by TDRs	13,337	13,429
Total Financing Receivable by TDRs	13,337	13,429
Total Financing Receivable by TDRs	$13,337	$13,429

Allowance_for_Loan_Losses_Allo

Allowance for Loan Losses - Allowance for Loan Losses by Loan Type (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	$27,833	$28,103
Loan chargeoffs	'	-115
Loan recoveries	85	1,222
Provision (credit) for loan losses	-500	-1,000
Balance at end of period	27,418	28,210
Commercial Real Estate [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	18,403	19,051
Loan chargeoffs	'	-115
Loan recoveries	71	62
Provision (credit) for loan losses	339	-354
Balance at end of period	18,813	18,644
Multifamily [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	5,097	6,881
Loan chargeoffs	'	'
Loan recoveries	14	677
Provision (credit) for loan losses	1	-1,941
Balance at end of period	5,112	5,617
One to Four Family [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	3,017	1,120
Loan chargeoffs	'	'
Loan recoveries	'	'
Provision (credit) for loan losses	-385	1,851
Balance at end of period	2,632	2,971
Land [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	1,308	1,043
Loan chargeoffs	'	'
Loan recoveries	'	483
Provision (credit) for loan losses	-455	-556
Balance at end of period	853	970
All Other [Member]	'	'
Financing Receivable, Allowance for Credit Losses [Line Items]	'	'
Balance at beginning of period	8	8
Loan chargeoffs	'	'
Loan recoveries	'	'
Provision (credit) for loan losses	'	'
Balance at end of period	$8	$8

Allowance_for_Loan_Losses_Allo1

Allowance for Loan Losses - Allowance for Loan Losses by Loan Type (Parenthetical) (Detail) (USD $)	3 Months Ended		12 Months Ended
In Millions, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
	Security_Loan	SecurityLoan	Security_Loan
Receivables [Abstract]	'	'	'
Net Proceeds of loans	'	$2.60	'
Recovery of prior loan charge offs	'	1.1	'
Recovery of prior real estate expenses	'	$1.50	'
Number of loans associated with recoveries of prior real estate expenses	1	1	1

Allowance_for_Loan_Losses_Loan

Allowance for Loan Losses - Loans Receivable by Segment and Impairment Evaluation and Allowance for Loan Losses (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2013	Dec. 31, 2012
In Thousands, unless otherwise specified
Loans:	'	'	'	'
Individually evaluated for impairment	$59,864	$57,160	'	'
Collectively evaluated for impairment	1,086,570	1,074,390	'	'
Total loans	1,146,434	1,131,550	'	'
Allowance for loan losses:	'	'	'	'
Individually evaluated for impairment	5,710	6,093	'	'
Collectively evaluated for impairment	21,708	21,740	'	'
Total allowance for loan losses	27,418	27,833	28,210	28,103
Commercial Real Estate [Member]	'	'	'	'
Loans:	'	'	'	'
Individually evaluated for impairment	54,312	52,407	'	'
Collectively evaluated for impairment	807,788	786,359	'	'
Total loans	862,100	838,766	'	'
Allowance for loan losses:	'	'	'	'
Individually evaluated for impairment	5,045	4,999	'	'
Collectively evaluated for impairment	13,768	13,404	'	'
Total allowance for loan losses	18,813	18,403	'	'
Multifamily [Member]	'	'	'	'
Loans:	'	'	'	'
Individually evaluated for impairment	3,962	3,128	'	'
Collectively evaluated for impairment	205,631	207,142	'	'
Total loans	209,593	210,270	'	'
Allowance for loan losses:	'	'	'	'
Individually evaluated for impairment	617	594	'	'
Collectively evaluated for impairment	4,495	4,503	'	'
Total allowance for loan losses	5,112	5,097	'	'
One to Four Family [Member]	'	'	'	'
Loans:	'	'	'	'
Individually evaluated for impairment	'	'	'	'
Collectively evaluated for impairment	64,366	72,064	'	'
Total loans	64,366	72,064	'	'
Allowance for loan losses:	'	'	'	'
Individually evaluated for impairment	'	'	'	'
Collectively evaluated for impairment	2,632	3,017	'	'
Total allowance for loan losses	2,632	3,017	'	'
Land [Member]	'	'	'	'
Loans:	'	'	'	'
Individually evaluated for impairment	1,590	1,625	'	'
Collectively evaluated for impairment	7,526	7,553	'	'
Total loans	9,116	9,178	'	'
Allowance for loan losses:	'	'	'	'
Individually evaluated for impairment	48	500	'	'
Collectively evaluated for impairment	805	808	'	'
Total allowance for loan losses	853	1,308	'	'
All Other [Member]	'	'	'	'
Loans:	'	'	'	'
Individually evaluated for impairment	'	'	'	'
Collectively evaluated for impairment	1,259	1,272	'	'
Total loans	1,259	1,272	'	'
Allowance for loan losses:	'	'	'	'
Individually evaluated for impairment	'	'	'	'
Collectively evaluated for impairment	8	8	'	'
Total allowance for loan losses	$8	$8	'	'

Foreclosed_Real_Estate_and_Val2

Foreclosed Real Estate and Valuation Allowance for Real Estate Losses - Summary of Real Estate Acquired through Foreclosure by Property Type (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified	Property	Property
Real Estate Properties [Line Items]	'	'
# of Properties	2	3
Amount	$9,335	$10,669
Commercial Real Estate [Member]	'	'
Real Estate Properties [Line Items]	'	'
# of Properties	1	2
Amount	2,650	3,984
Multifamily [Member]	'	'
Real Estate Properties [Line Items]	'	'
# of Properties	1	1
Amount	$6,685	$6,685

Foreclosed_Real_Estate_and_Val3

Foreclosed Real Estate and Valuation Allowance for Real Estate Losses - Summary of Activity in the Valuation Allowance for Real Estate Losses (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Real Estate [Abstract]	'	'
Valuation allowance at beginning of period	$2,017	$5,339
Chargeoffs	-824	'
Provision for real estate losses	'	629
Valuation allowance at end of period	$1,193	$5,968

Deposits_Scheduled_Maturities_

Deposits - Scheduled Maturities of Certificates of Deposits (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Time Deposits By Maturity [Abstract]	'	'
Within one year, Amount	$324,311	$307,122
Over one to two years, Amount	131,082	167,323
Over two to three years, Amount	215,603	170,956
Over three to four years, Amount	90,665	106,700
Over four years, Amount	149,815	129,678
Total certificates of deposit, Amount	$911,476	$881,779
Within one year, Wtd-Avg Stated Rate	1.96%	1.97%
Over one to two years, Wtd-Avg Stated Rate	1.70%	1.92%
Over two to three years, Wtd-Avg Stated Rate	1.96%	1.92%
Over three to four years, Wtd-Avg Stated Rate	2.31%	2.50%
Over four years, Wtd-Avg Stated Rate	2.04%	2.06%
Total certificates of deposit, Wtd-Avg Stated Rate	1.97%	2.03%

Deposits_Additional_Informatio

Deposits - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
Assets Sold under Agreements to Repurchase [Line Items]	'	'
CDs of $100,000 or more	$506,000,000	$473,000,000
Brokered certificate deposits amount	87,000,000	91,000,000
Due within one year	324,311,000	307,122,000
Due over one to two years	131,082,000	167,323,000
Due over two to three years	215,603,000	170,956,000
Due over three to four years	90,665,000	106,700,000
Due thereafter	149,815,000	129,678,000
CDs of $100,000 or More [Member]	'	'
Assets Sold under Agreements to Repurchase [Line Items]	'	'
Due within one year	147,000,000	'
Due over one to two years	62,000,000	'
Due over two to three years	139,000,000	'
Due over three to four years	58,000,000	'
Due thereafter	100,000,000	'
Brokered CDs [Member]	'	'
Assets Sold under Agreements to Repurchase [Line Items]	'	'
Due within one year	19,000,000	'
Due over one to two years	8,000,000	'
Due over two to three years	14,000,000	'
Due over three to four years	25,000,000	'
Due thereafter	$21,000,000	'
Brokered certificates deposits weighted average rate	2.93%	'

Lines_of_Credit_Additional_Inf

Lines of Credit - Additional Information (Detail) (Federal Home Loan Bank of New York and Federal Reserve Bank of New York [Member], USD $)	Mar. 31, 2014
In Millions, unless otherwise specified
Federal Home Loan Bank of New York and Federal Reserve Bank of New York [Member]	'
Federal Home Loan Bank Advances Type Of Fhlb Advances [Line Items]	'
Unsecured credit lines	$41
Additional total borrowings from FHLB and FRB	368
Borrowings	$0

Subordinated_Debentures_Capita2

Subordinated Debentures - Capital Securities - Summary of Capital Securities Outstanding (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Debt Instrument [Line Items]	'	'
Accrued Interest Payable	$67	$868
Capital Securities II [Member]	'	'
Debt Instrument [Line Items]	'	'
Principal	15,464	15,464
Accrued Interest Payable	20	275
Interest Rate	3.18%	3.19%
Capital Securities III [Member]	'	'
Debt Instrument [Line Items]	'	'
Principal	15,464	15,464
Accrued Interest Payable	20	261
Interest Rate	3.02%	3.03%
Capital Securities IV [Member]	'	'
Debt Instrument [Line Items]	'	'
Principal	15,464	15,464
Accrued Interest Payable	19	223
Interest Rate	2.63%	2.65%
Capital Securities V [Member]	'	'
Debt Instrument [Line Items]	'	'
Principal	10,310	10,310
Accrued Interest Payable	8	109
Interest Rate	1.88%	1.89%
Capital Securities [Member]	'	'
Debt Instrument [Line Items]	'	'
Principal	56,702	56,702
Accrued Interest Payable	$67	$868

Common_Stock_Warrant_and_Equit2

Common Stock Warrant and Equity Incentive Plans - Additional Information (Detail) (USD $)	3 Months Ended		12 Months Ended	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014	Mar. 31, 2014
			Executive Officers [Member]	Stock Appreciation Right [Member]	Stock Appreciation Right [Member]	Cash-Settled Stock Appreciation Rights (SARs) [Member]	Long Term Incentive Plan [Member]
			Installment	Installment	Executive Officers [Member]
			Executives		Executives
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'	'	'	'	'	'
Maximum number of shares of common stock that may be awarded	'	'	'	'	'	'	2,250,000
Common stock were available for award	'	'	'	'	'	'	620,403
Issuance of common stock option	'	'	'	'	'	'	0
Shares Awarded	'	'	'	'	78,000	'	'
Number of participants	'	'	5	'	5	'	'
Number of installments	'	'	2	3	'	'	'
Contractual term	'	'	'	'5 years	'	'	'
Exercise price of option	'	'	'	$7.65	'	'	'
Estimated fair value per option	'	'	'	$2.28	'	'	'
Estimated fair value of SARs	'	'	'	$178,000	'	'	'
Expected dividend yield	'	'	'	1.75%	'	'	'
Expected stock volatility	'	'	'	45.00%	'	'	'
Risk-free interest rate	'	'	'	0.98%	'	'	'
Expected term in years	'	'	'	'3 years 6 months	'	'	'
Stock-based compensation expense	495,000	254,000	'	'	'	11,000	'
Pre-tax, stock-based compensation cost related to all nonvested awards of options and restricted stock not yet recognized	2,300,000	'	'	'	'	'	'
Options and restricted stock not yet recognized and will be recognized over a weighted-average period	'2 years 1 month 6 days	'	'	'	'	'	'
Net tax benefit	$292,000	$145,000	'	'	'	'	'

Common_Stock_Warrant_and_Equit3

Common Stock Warrant and Equity Incentive Plans - Summary of the Activity in IBC's Outstanding Common Stock Warrant and Options (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Beginning Outstanding	1,041,445
Forfeited/expired	-1,400
Options exercised	-10,567
Ending Outstanding	1,029,478
Vested and exercisable	99.00%
Wtd-avg contractual remaining term (in years)	'4 years 10 months 24 days
Intrinsic value at December 31, 2013	$1,866
Wtd-Avg Exercise Price, Beginning Outstanding	$6.64
Wtd-Avg Exercise Price, Forfeited/expired	$7.14
Wtd-Avg Exercise Price, Options exercised	$2.87
Wtd-Avg Exercise Price, Ending Outstanding	$6.68
Exercise Price Per Warrant/Option $5.42 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$5.42
Beginning Outstanding	691,882
Forfeited/expired	'
Options exercised	'
Ending Outstanding	691,882
Expiration date	23-Dec-18
Vested and exercisable	100.00%
Wtd-avg contractual remaining term (in years)	'4 years 8 months 12 days
Intrinsic value at December 31, 2013	1,405
Exercise Price Per Warrant/Option $17.10 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$17.10
Beginning Outstanding	110,640
Forfeited/expired	-300
Options exercised	'
Ending Outstanding	110,340
Expiration date	13-Dec-17
Vested and exercisable	100.00%
Wtd-avg contractual remaining term (in years)	'3 years 8 months 12 days
Intrinsic value at December 31, 2013	'
Exercise Price Per Warrant/Option $7.50 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$7.50
Beginning Outstanding	113,990
Forfeited/expired	-300
Options exercised	'
Ending Outstanding	113,690
Expiration date	11-Dec-18
Vested and exercisable	100.00%
Wtd-avg contractual remaining term (in years)	'4 years 8 months 12 days
Intrinsic value at December 31, 2013	'
Exercise Price Per Warrant/Option $4.02 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$4.02
Beginning Outstanding	57,400
Forfeited/expired	-300
Options exercised	-900
Ending Outstanding	56,200
Expiration date	10-Dec-19
Vested and exercisable	100.00%
Wtd-avg contractual remaining term (in years)	'5 years 8 months 12 days
Intrinsic value at December 31, 2013	193
Exercise Price Per Warrant/Option $3.00 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$3
Beginning Outstanding	32,400
Forfeited/expired	-300
Options exercised	-4,600
Ending Outstanding	27,500
Expiration date	9-Dec-20
Vested and exercisable	100.00%
Wtd-avg contractual remaining term (in years)	'6 years 8 months 12 days
Intrinsic value at December 31, 2013	122
Exercise Price Per Warrant/Option $2.55 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$2.55
Beginning Outstanding	35,133
Forfeited/expired	-200
Options exercised	-5,067
Ending Outstanding	29,866
Expiration date	8-Dec-21
Vested and exercisable	67.00%
Wtd-avg contractual remaining term (in years)	'7 years 8 months 12 days
Intrinsic value at December 31, 2013	$146

Common_Stock_Warrant_and_Equit4

Common Stock Warrant and Equity Incentive Plans - Summary of the Activity in IBC's Outstanding Common Stock Warrant and Options (Parenthetical) (Detail) (USD $)	3 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of warrants purchased	1,029,478	1,041,445
Vested and exercisable	99.00%	'
Calculated intrinsic value	$7.45	'
Exercise Price Per Warrant/Option $5.42 [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of warrants purchased	691,882	691,882
Exercise Price Per Warrant/Option	$5.42	'
Vested and exercisable	100.00%	'
Price Per Share $2.55 [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Exercise Price Per Warrant/Option	$2.55	'
Vested and exercisable	100.00%	'

Common_Stock_Warrant_and_Equit5

Common Stock Warrant and Equity Incentive Plans - Summary of Selected Information Regarding Awards of Restricted Common Stock Awards Made Under Plans (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Grant date of award, Stock Grant	23-Jan-14	24-Jan-13
Total restricted shares of stock awarded	92,000	330,700
Grant date per share fair value	$7.65	$4.50
Total estimated fair value of award	$703,800	$1,488,150
Awards scheduled to vest as follows:	'	'
Awards scheduled to vest, Stock Grant	92,000	330,700
January 2014 [Member]	'	'
Awards scheduled to vest as follows:	'	'
Awards scheduled to vest, Stock Grant	'	49,566
January 2015 [Member]	'	'
Awards scheduled to vest as follows:	'	'
Awards scheduled to vest, Stock Grant	30,664	170,888
January 2016 [Member]	'	'
Awards scheduled to vest as follows:	'	'
Awards scheduled to vest, Stock Grant	30,664	110,246
January 2017 [Member]	'	'
Awards scheduled to vest as follows:	'	'
Awards scheduled to vest, Stock Grant	30,672	'

Common_Stock_Warrant_and_Equit6

Common Stock Warrant and Equity Incentive Plans - Summary of Selected Information Regarding Awards of Restricted Common Stock Awards Made Under Plans (Parenthetical) (Detail)	3 Months Ended	12 Months Ended
	Mar. 31, 2014	Dec. 31, 2013
	Executives
Restricted Common Stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares Awarded	92,000	'
Executive Officers [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of participants	'	5
Number of installments	'	2
Restricted stock awards vesting in second anniversary of the grant	'	66.67%
Restricted stock awards vesting in third anniversary of the grant	'	33.33%
Executive Officers [Member] | Restricted Common Stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares Awarded	12,000	182,000
Number of participants	5	'
Non-employee Directors [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of participants	'	8
Restricted stock awards vesting in first anniversary of the grant	'	33.33%
Restricted stock awards vesting in second anniversary of the grant	'	33.33%
Restricted stock awards vesting in third anniversary of the grant	'	33.33%
Non-employee Directors [Member] | Restricted Common Stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares Awarded	80,000	80,000
Number of participants	8	'
Other Officers and Employees [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Number of installments	3	3
Restricted stock awards vesting in first anniversary of the grant	33.33%	33.33%
Restricted stock awards vesting in second anniversary of the grant	33.33%	33.33%
Restricted stock awards vesting in third anniversary of the grant	33.33%	33.33%
Other Officers and Employees [Member] | Restricted Common Stock [Member]	'	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'	'
Shares Awarded	'	68,700

Common_Stock_Warrant_and_Equit7

Common Stock Warrant and Equity Incentive Plans - Summary of Outstanding Restricted Common Stock and Related Information (Detail) (Restricted Common Stock [Member], USD $)	3 Months Ended
	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Beginning Outstanding	573,317
Shares vested and no longer restricted	-224,116
Shares granted	92,000
Ending Outstanding	441,201
Wtd-Avg price outstanding, Beginning Balance	$4.70
Wtd-Avg price , Shares vested and no longer restricted	$4.69
Wtd-Avg price , Shares granted	$7.65
Wtd-Avg price outstanding, Ending Balance	$5.32
Price Per Share $2.90 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Price Per Share	$2.90
Beginning Outstanding	158,317
Shares vested and no longer restricted	-101,035
Shares granted	'
Ending Outstanding	57,282
Price Per Share $4.50 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Price Per Share	$4.50
Beginning Outstanding	279,500
Shares vested and no longer restricted	-47,664
Shares granted	'
Ending Outstanding	231,836
Price Per Share $7.21 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Price Per Share	$7.21
Beginning Outstanding	135,500
Shares vested and no longer restricted	-75,417
Shares granted	'
Ending Outstanding	60,083
Price Per Share $7.65 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Price Per Share	$7.65
Beginning Outstanding	'
Shares vested and no longer restricted	'
Shares granted	92,000
Ending Outstanding	92,000

Common_Stock_Warrant_and_Equit8

Common Stock Warrant and Equity Incentive Plans - Summary of Outstanding Restricted Common Stock and Related Information (Parenthetical) (Detail) (Restricted Common Stock [Member], USD $)	3 Months Ended
	Mar. 31, 2014
Price Per Share $2.90 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$2.90
Price Per Share $2.90 [Member] | January 19, 2015 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 1	57,282
Price Per Share $4.50 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$4.50
Price Per Share $4.50 [Member] | January 24, 2015 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 1	138,664
Price Per Share $4.50 [Member] | January 24, 2016 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 2	93,172
Price Per Share $7.21 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$7.21
Price Per Share $7.21 [Member] | January 19, 2015 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 1	14,584
Price Per Share $7.21 [Member] | January 24, 2015 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 2	30,333
Price Per Share $7.21 [Member] | January 24, 2016 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 3	15,166
Price Per Share $7.65 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Exercise Price Per Warrant/Option	$7.65
Price Per Share $7.65 [Member] | January 23, 2015 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 1	30,664
Price Per Share $7.65 [Member] | January 23, 2016 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 2	30,664
Price Per Share $7.65 [Member] | January 23, 2017 [Member]	'
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]	'
Restricted common stock will vest on date 3	30,672

Earning_Per_Common_Share_Summa

Earning Per Common Share - Summary of Basic and Diluted Earnings Per Common Share (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Basic Earnings Per Common Share:	'	'
Net earnings available to common stockholders	$3,842	$3,429
Weighted-Average number of common shares outstanding	21,991,451	21,832,200
Basic earnings per common share	$0.17	$0.16
Diluted Earnings Per Common Share:	'	'
Net earnings applicable to common stockholders	$3,842	$3,429
Weighted-Average number of common shares outstanding:	'	'
Common shares outstanding	21,991,451	21,832,200
Potential dilutive shares resulting from exercise of warrants /options	229,050	22,255
Total average number of common shares outstanding used for dilution	22,220,501	21,854,455
Diluted earnings per common share	$0.17	$0.16

Earning_Per_Common_Share_Summa1

Earning Per Common Share - Summary of Basic and Diluted Earnings Per Common Share (Parenthetical) (Detail)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Earnings Per Share [Abstract]	'	'
Outstanding options/warrants to purchase, shares	110,340	928,112

Regulatory_Matters_and_Regulat1

Regulatory Matters and Regulatory Capital - Additional Information (Detail)	Mar. 31, 2014
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'
Tier 1 capital ratio	20.64
Tier 1 Total capital ratios	21.9
Leverage capital ratio	16.12%
INB [Member]	'
Compliance with Regulatory Capital Requirements for Mortgage Companies [Line Items]	'
Tier 1 capital ratio	15.55
Tier 1 Total capital ratios	19.84
Leverage capital ratio	21.10%

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale, net	$980	$965
Fair Value, Inputs, Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Securities available for sale, net	1,000	1,000
Liabilities that were recorded at fair value	$0	$0

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets Measured at Fair Value on a Nonrecurring Basis (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013	Dec. 31, 2013
Impaired Securities [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Total Losses (Gains)	'	$366	'
Foreclosure Real Estate [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accumulated Losses on Outstanding Balance	1,193	'	2,017
Total Losses (Gains)	-72	629	'
Impaired Loans [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accumulated Losses on Outstanding Balance	12,163	'	12,616
Total Losses (Gains)	-453	-48	'
Impaired Loans [Member] | Commercial Real Estate [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accumulated Losses on Outstanding Balance	11,498	'	11,522
Total Losses (Gains)	-24	389	'
Impaired Loans [Member] | Multifamily [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accumulated Losses on Outstanding Balance	617	'	594
Total Losses (Gains)	23	-423	'
Impaired Loans [Member] | Land [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Accumulated Losses on Outstanding Balance	48	'	500
Total Losses (Gains)	-452	-14	'
Level 3 [Member] | Foreclosure Real Estate [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Outstanding Carrying Value	9,335	'	10,669
Level 3 [Member] | Impaired Loans [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Outstanding Carrying Value	59,864	'	57,160
Level 3 [Member] | Impaired Loans [Member] | Commercial Real Estate [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Outstanding Carrying Value	54,312	'	52,407
Level 3 [Member] | Impaired Loans [Member] | Multifamily [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Outstanding Carrying Value	3,962	'	3,128
Level 3 [Member] | Impaired Loans [Member] | Land [Member]	'	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'	'
Outstanding Carrying Value	$1,590	'	$1,625

Fair_Value_Measurements_Change

Fair Value Measurements - Change in Assets Measured at Fair Value on a Nonrecurring Basis (Detail) (Assets Measured at Fair Value on a Nonrecurring Basis [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2014	Mar. 31, 2013
Impaired Securities [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Beginning balance	'	$3,721
Net new impaired loans	'	'
Principal repayments/sales	'	-63
Chargeoffs	'	'
Gain from sales	'	'
Transferred to foreclosed real estate	'	'
Other than temporary impairment writedowns	'	-366
Writedowns of carrying value subsequent to foreclosure	'	'
Ending balance	'	3,292
Impaired Loans [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Beginning balance	57,160	65,973
Net new impaired loans	3,466	1,485
Principal repayments/sales	-762	-9,467
Chargeoffs	'	-115
Gain from sales	'	'
Transferred to foreclosed real estate	'	-3,040
Other than temporary impairment writedowns	'	'
Writedowns of carrying value subsequent to foreclosure	'	'
Ending balance	59,864	54,836
Foreclosure Real Estate [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]	'	'
Beginning balance	10,669	15,923
Net new impaired loans	'	'
Principal repayments/sales	-1,406	'
Chargeoffs	'	'
Gain from sales	72	'
Transferred to foreclosed real estate	'	3,040
Other than temporary impairment writedowns	'	'
Writedowns of carrying value subsequent to foreclosure	'	-629
Ending balance	$9,335	$18,334

Fair_Value_Measurements_Carryi

Fair Value Measurements - Carrying and Estimated Fair Values of Financial Instruments (Detail) (USD $)	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Financial Assets:	'	'
Securities available for sale, net	$980	$965
Securities held to maturity, net	342,888	378,507
Fair Value [Member]	'	'
Financial Assets:	'	'
Cash and cash equivalents	79,157	24,700
Time deposits with banks	5,370	5,370
Securities available for sale, net	980	965
Securities held to maturity, net	342,888	378,507
FRB and FHLB stock	8,260	8,244
Loans receivable, net	1,119,116	1,100,858
Accrued interest receivable	4,630	4,861
Loan fees receivable	1,788	1,808
Total Financial Assets	1,562,189	1,525,313
Financial Liabilities:	'	'
Deposits	1,316,092	1,294,690
Borrowed funds plus accrued interest payable	56,460	57,260
Accrued interest payable on deposits	1,099	1,508
Commitments to lend	450	408
Total Financial Liabilities	1,374,101	1,353,866
Net Financial Assets	188,088	171,447
Carrying Value [Member]	'	'
Financial Assets:	'	'
Cash and cash equivalents	79,157	24,700
Time deposits with banks	5,370	5,370
Securities available for sale, net	980	965
Securities held to maturity, net	346,425	383,937
FRB and FHLB stock	8,260	8,244
Loans receivable, net	1,114,813	1,099,689
Accrued interest receivable	4,630	4,861
Loan fees receivable	2,266	2,298
Total Financial Assets	1,561,901	1,530,064
Financial Liabilities:	'	'
Deposits	1,303,972	1,282,232
Borrowed funds plus accrued interest payable	56,769	57,570
Accrued interest payable on deposits	1,099	1,508
Commitments to lend	450	408
Total Financial Liabilities	1,362,290	1,341,718
Net Financial Assets	$199,611	$188,346

Subsequent_Event_Additional_In

Subsequent Event - Additional Information (Detail) (Subsequent Event [Member], USD $)	0 Months Ended
	Apr. 24, 2014
Subsequent Event [Member]	'
Subsequent Event [Line Items]	'
Dividend declared per share	$0.05
Dividend payable date	26-May-14
Dividend payable date of record	15-May-14