Acquisition Activity (Schedule Of Business Acquisition) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 years months
Omni Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Estimated life of portfolio on interest expenses declining basis (in months)	60
Cameron Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Estimated deposit base on intangible assets (in years)	10
Estimated life of portfolio on interest expenses declining basis (in months)	69
As Acquired [Member] | Omni Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	54,683
Investment securities	91,808
Loans	503,695
Other real estate owned	24,759
Deferred tax asset	1,398
Other assets	56,294
Total Assets	732,637
Interest-bearing deposits	504,615
Noninterest-bearing deposits	129,181
Borrowings	58,168
Other liabilities	3,971
Total Liabilities	695,935
As Acquired [Member] | Cameron Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	29,191
Investment securities	223,720
Loans	404,633
Other real estate owned	710
Deferred tax asset	2,778
Other assets	41,747
Total Assets	702,779
Interest-bearing deposits	402,090
Noninterest-bearing deposits	164,363
Borrowings	46,804
Other liabilities	2,124
Total Liabilities	615,381
Fair Value Adjustments [Member] | Omni Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Investment securities	(789)	[1]
Loans	(62,248)	[2]
Other real estate owned	(8,506)	[3]
Core deposit intangible	829	[4]
Deferred tax asset	32,009	[5]
Other assets	(12,653)	[6]
Total Assets	(51,358)
Interest-bearing deposits	1,812	[7]
Borrowings	196	[8]
Other liabilities	903	[9]
Total Liabilities	2,911
Fair Value Adjustments [Member] | Cameron Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Investment securities	(35)	[10]
Loans	(22,559)	[11]
Other real estate owned	(315)	[12]
Core deposit intangible	5,178	[4]
Deferred tax asset	9,208	[13]
Other assets	(4,175)	[14]
Total Assets	(12,698)
Interest-bearing deposits	818	[15]
Borrowings	2,198	[16]
Total Liabilities	3,016
As Recorded By IBERIABANK [Member] | Omni Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	54,683
Investment securities	91,019
Loans	441,447
Other real estate owned	16,253
Core deposit intangible	829
Deferred tax asset	33,407
Other assets	43,641
Total Assets	681,279
Interest-bearing deposits	506,427
Noninterest-bearing deposits	129,181
Borrowings	58,364
Other liabilities	4,874
Total Liabilities	698,846
As Recorded By IBERIABANK [Member] | Cameron Bancshares, Inc. [Member]
Business Acquisition [Line Items]
Cash and cash equivalents	29,191
Investment securities	223,685
Loans	382,074
Other real estate owned	395
Core deposit intangible	5,178
Deferred tax asset	11,986
Other assets	37,572
Total Assets	690,081
Interest-bearing deposits	402,908
Noninterest-bearing deposits	164,363
Borrowings	49,002
Other liabilities	2,124
Total Liabilities	618,397

[1] The adjustment represents the write down of the book value of OMNI's investments to their estimated fair value based on fair values on the date of acquisition.

[2] The adjustment represents the write down of the book value of OMNI's loans to their estimated fair value based on current interest rates and expected cash flows which includes an estimate of expected loan losses inherent in the portfolio.

[3] The adjustment represents the write down of the book value of OMNI's OREO properties to their estimated fair value at the acquisition date based on their appraised value, as adjusted for costs to sell.

[4] The adjustment represents the value of the core deposit base assumed in the acquisition. The core deposit asset was recorded as an identifiable intangible asset and will be amortized on an accelerated basis over the average life of the deposit base, estimated to be 10 years.

[5] The adjustment represents the value of the deferred tax asset recognized on the fair value adjustments of OMNI's acquired assets and assumed liabilities.

[6] The adjustment represents the write down of the book value of OMNI's property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value.

[7] The adjustment is necessary because the weighted average interest rate of OMNI's CD's exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce interest expense over the life of the portfolio, which is estimated at 60 months.

[8] The adjustment is necessary because the interest rate of OMNI's fixed rate borrowings exceeded current interest rates on similar borrowings.

[9] The adjustment is necessary because the fair value of the Company's liability under assumed lease agreements from OMNI is lower than the total cash payments remaining under the existing leases.

[10] The adjustment represents the write down of the book value of Cameron's investments to their estimated fair value based on fair values on the date of acquisition.

[11] The adjustment represents the write up of the book value of Cameron's loans to their estimated fair value based on current interest rates and expected cash flows, which includes an estimate of expected loan losses inherent in the portfolio.

[12] The adjustment represents the write down of the book value of Cameron's OREO properties to their estimated fair value at the acquisition date based on their appraised value, as adjusted for costs to sell.

[13] The adjustment represents the value of the deferred tax asset recognized on the fair value adjustments of Cameron's acquired assets and assumed liabilities.

[14] The adjustment represents the write down of the book value of Cameron's property, equipment, and other assets to their estimated fair value at the acquisition date based on their appraised value.

[15] The adjustment is necessary because the weighted average interest rate of Cameron's CD's exceeded the cost of similar funding at the time of acquisition. The fair value adjustment will be amortized to reduce interest expense on a declining basis over the life of the portfolio, which is estimated at 69 months.

[16] The adjustment is necessary because the interest rate of Cameron's fixed rate borrowings exceeded current interest rates on similar borrowings.