Bank OZK 10-Q 8 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 30, 2015
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Trading Symbol	OZRK
Entity Registrant Name	BANK OF THE OZARKS INC
Entity Central Index Key	1038205
Current Fiscal Year End Date	-19
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		86,773,975

Consolidated_Balance_Sheets

Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
ASSETS
Cash and due from banks	$425,794	$147,751	$187,101
Interest earning deposits	2,988	2,452	1,250
Cash and cash equivalents	428,782	150,203	188,351
Investment securities - available for sale ("AFS")	784,275	839,321	687,661
Non-purchased loans and leases	4,311,105	3,979,870	2,778,503
Purchased loans	2,042,164	1,147,947	793,488
Total loans and leases	6,353,269	5,127,817	3,571,991
Allowance for loan and lease losses	-54,147	-52,918	-43,861
Net loans and leases	6,299,122	5,074,899	3,528,130
Federal Deposit Insurance Corporation ("FDIC") loss share receivable	0	0	57,782
Premises and equipment, net	282,073	273,591	254,973
Foreclosed assets	32,094	37,775	60,869
Accrued interest receivable	25,179	20,192	15,486
Bank owned life insurance ("BOLI")	182,649	182,052	144,601
Intangible assets, net	155,510	105,576	20,993
Other, net	113,723	82,890	74,149
Total assets	8,303,407	6,766,499	5,032,995
LIABILITIES AND STOCKHOLDERS' EQUITY
Demand non-interest bearing	1,265,165	1,145,454	886,341
Savings and interest bearing transaction	3,298,807	2,892,989	2,199,545
Time	2,152,689	1,457,939	830,318
Total deposits	6,716,661	5,496,382	3,916,204
Repurchase agreements with customers	76,960	65,578	51,140
Other borrowings	161,318	190,855	280,885
Subordinated debentures	117,264	64,950	64,950
FDIC clawback payable	0	0	26,202
Accrued interest payable and other liabilities	48,472	36,892	32,842
Total liabilities	7,120,675	5,854,657	4,372,223
Commitments and contingencies
Stockholders' equity:
Preferred stock; $0.01 par value; 1,000,000 shares authorized; no shares outstanding at March 31, 2015 and 2014 or at December 31, 2014	0	0	0
Common stock; $0.01 par value; 125,000,000 shares authorized; 86,758,375, 73,888,304 and 79,924,350 shares issued at March 31, 2015, March 31, 2014 and December 31, 2014, respectively	867	799	739
Additional paid-in capital	563,087	324,354	147,214
Retained earnings	600,935	571,454	506,146
Accumulated other comprehensive income	14,367	14,132	3,211
Treasury stock, at cost, none at March 31, 2015 or March 31, 2014, 72,268 shares at December 31, 2014	0	-2,349	0
Total stockholders' equity before noncontrolling interest	1,179,256	908,390	657,310
Noncontrolling interest	3,476	3,452	3,462
Total stockholders' equity	1,182,732	911,842	660,772
Total liabilities and stockholders' equity	$8,303,407	$6,766,499	$5,032,995

Consolidated_Balance_Sheets_Pa

Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Statement of Financial Position [Abstract]
Preferred stock, par value	$0.01	$0.01	$0.01
Preferred stock, shares authorized	1,000,000	1,000,000	1,000,000
Preferred stock, shares outstanding	0	0	0
Common stock, par value	$0.01	$0.01	$0.01
Common stock, shares authorized	125,000,000	125,000,000	125,000,000
Common stock, shares issued	86,758,375	79,924,350	73,888,304
Treasury stock, Shares	0	72,268	0

Consolidated_Statements_of_Inc

Consolidated Statements of Income (Unaudited) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest income:
Non-purchased loans and leases	$50,432	$33,412
Purchased loans	32,860	16,885
Investment securities:
Taxable	3,485	2,360
Tax-exempt	4,669	4,397
Deposits with banks and federal funds sold	9	3
Total interest income	91,455	57,057
Interest expense:
Deposits	3,537	1,581
Repurchase agreements with customers	17	12
Other borrowings	1,703	2,655
Subordinated debentures	709	413
Total interest expense	5,966	4,661
Net interest income	85,489	52,396
Provision for loan and lease losses	6,315	1,304
Net interest income after provision for loan and lease losses	79,174	51,092
Non-interest income:
Service charges on deposit accounts	6,627	5,639
Mortgage lending income	1,507	954
Trust income	1,432	1,316
BOLI income	3,623	1,130
Net accretion of FDIC loss share receivable and FDIC clawback payable	0	692
Other income from purchased loans, net	8,908	3,311
Net gains on investment securities	2,534	5
Gains on sales of other assets	2,829	974
Gain on merger and acquisition transaction	0	4,667
Other	1,607	1,672
Total non-interest income	29,067	20,360
Non-interest expense:
Salaries and employee benefits	22,597	17,689
Net occupancy and equipment	7,291	5,044
Other operating expenses	20,296	14,721
Total non-interest expense	50,184	37,454
Income before taxes	58,057	33,998
Provision for income taxes	18,139	8,730
Net income	39,918	25,268
Earnings attributable to noncontrolling interest	-24	8
Net income available to common stockholders	$39,894	$25,276
Basic earnings per common share	$0.48	$0.34
Diluted earnings per common share	$0.47	$0.34
Dividends declared per common share	$0.13	$0.11

Consolidated_Statements_of_Com

Consolidated Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$39,918	$25,268
Other comprehensive income:
Unrealized gains and losses on investment securities AFS	2,914	11,330
Tax effect of unrealized gains and losses on investment securities AFS	-1,110	-4,444
Reclassification of gains and losses on investment securities AFS included in net income	-2,534	-5
Tax effect of reclassification of gains and losses on investment securities AFS included in net income	965	2
Total other comprehensive income	235	6,883
Total comprehensive income	$40,153	$32,151

Consolidated_Statements_of_Sto

Consolidated Statements of Stockholder's Equity (Unaudited) (USD $)	Total	Common Stock [Member]	Additional Paid-In Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Non-Controlling Interest [Member]
In Thousands
Balances at Dec. 31, 2013	$632,530	$739	$143,015	$488,978	($3,672)	$0	$3,470
Net income	25,268	0	0	25,268	0	0	0
Earnings attributable to noncontrolling interest	0	0	0	8	0	0	-8
Total other comprehensive income	6,883	0	0	0	6,883	0	0
Common stock dividends paid	-8,108	0	0	-8,108	0	0	0
Issuance of common stock for exercise of stock options	1,505	0	1,505	0	0	0	0
Excess tax benefit on exercise and forfeiture of stock options and vesting of restricted common stock	1,323	0	1,323	0	0	0	0
Stock-based compensation expense	1,371	0	1,371	0	0	0	0
Balances at Mar. 31, 2014	660,772	739	147,214	506,146	3,211	0	3,462
Balances at Dec. 31, 2014	911,842	799	324,354	571,454	14,132	-2,349	3,452
Net income	39,918	0	0	39,918	0	0	0
Earnings attributable to noncontrolling interest	0	0	0	-24	0	0	24
Total other comprehensive income	235	0	0	0	235	0	0
Common stock dividends paid	-10,413	0	0	-10,413	0	0	0
Issuance of common stock for exercise of stock options	547	0	547	0	0	0	0
Issuance of unvested restricted common stock	0	2	-2,351	0	0	2,349	0
Excess tax benefit on exercise and forfeiture of stock options and vesting of restricted common stock	330	0	330	0	0	0	0
Stock-based compensation expense	1,897	0	1,897	0	0	0	0
Forfeiture of unvested restricted common stock	0	0	0	0	0	0	0
Issuance of common stock for acquisition	238,376	66	238,310	0	0	0	0
Balances at Mar. 31, 2015	$1,182,732	$867	$563,087	$600,935	$14,367	$0	$3,476

Consolidated_Statements_of_Sto1

Consolidated Statements of Stockholder's Equity (Unaudited) (Parenthetical) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Stockholders' Equity [Abstract]
Issuance of common stock for exercise of stock options, shares	53,000	176,600
Issuance of unvested restricted common stock, shares	243,300
Forfeiture of unvested restricted common stock, shares	27,250
Issuance of common stock for acquisitions	6,637,243
Common stock issuance costs	$100,000

Consolidated_Statements_of_Cas

Consolidated Statements of Cash Flows (Unaudited) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net income	$39,918	$25,268
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	2,131	1,855
Amortization	1,596	813
Earnings attributable to noncontrolling interest	-24	8
Provision for loan and lease losses	6,315	1,304
Provision for losses on foreclosed assets	2,203	64
Net amortization of investment securities AFS	70	111
Net gains on investment securities AFS	-2,534	-5
Originations of mortgage loans held for sale	-62,508	-38,748
Proceeds from sales of mortgage loans held for sale	58,990	38,535
Accretion of purchased loans	-32,860	-16,885
Net accretion of FDIC loss share receivable and FDIC clawback payable	0	-692
Gains on sales of other assets	-2,829	-974
Gain on merger and acquisition transaction	0	-4,667
Prepayment penalty on Federal Home Loan Bank of Dallas advances	2,480	0
Deferred income tax benefit	-277	-242
Increase in cash surrender value of BOLI	-1,362	-1,130
BOLI death benefits in excess of cash surrender value	-2,259	0
Excess tax benefit on exercise and forfeiture of stock options and vesting of restricted stock	-330	-1,323
Stock-based compensation expense	1,897	1,371
Changes in assets and liabilities:
Accrued interest receivable	-3,253	-813
Other assets, net	30,345	-285
Accrued interest payable and other liabilities	8,043	14,631
Net cash provided by operating activities	45,752	18,196
Cash flows from investing activities:
Proceeds from sales of investment securities AFS	30,117	1,224
Proceeds from maturities/calls/paydowns of investment securities AFS	50,187	13,279
Purchases of investment securities AFS	0	-18,349
Net increase of non-purchased loans and leases	-351,740	-148,100
Payments received on purchased loans	209,651	86,689
Payments received from FDIC under loss share agreements	0	10,610
Other net decreases in assets covered by FDIC loss share agreements and FDIC loss share receivable	0	5,423
Purchases of premises and equipment	-4,003	-3,433
Proceeds from sales of other assets	19,207	11,313
Cash invested in unconsolidated investments	-286	-881
Net cash received in merger and acquisition transactions	274,235	80,656
Net cash provided by investing activities	227,368	38,431
Cash flows from financing activities:
Net increase (decrease) in deposits	35,631	-56,742
Net repayments of other borrowings	-32,018	-266
Net increase (decrease) in repurchase agreements with customers	11,382	-1,963
Proceeds from exercise of stock options	547	1,505
Excess tax benefit on exercise and forfeiture of stock options and vesting of restricted stock	330	1,323
Cash dividends paid on common stock	-10,413	-8,108
Net cash provided (used) by financing activities	5,459	-64,251
Net increase (decrease) in cash and cash equivalents	278,579	-7,624
Cash and cash equivalents - beginning of period	150,203	195,975
Cash and cash equivalents - end of period	$428,782	$188,351

Organization_and_Principles_of

Organization and Principles of Consolidation	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Organization and Principles of Consolidation	1	Organization and Principles of Consolidation
	Bank of the Ozarks, Inc. (the “Company”) is a bank holding company headquartered in Little Rock, Arkansas, which operates under the rules and regulations of the Board of Governors of the Federal Reserve System. The Company owns a wholly-owned state chartered bank subsidiary – Bank of the Ozarks (the “Bank”), eight 100%-owned finance subsidiary business trusts – Ozark Capital Statutory Trust II (“Ozark II”), Ozark Capital Statutory Trust III (“Ozark III”), Ozark Capital Statutory Trust IV (“Ozark IV”), Ozark Capital Statutory Trust V (“Ozark V”) (collectively, the “Ozark Trusts”), Intervest Statutory Trust II (“Intervest II”), Intervest Statutory Trust III (“Intervest III”), Intervest Statutory Trust IV (“Intervest IV”) and Intervest Statutory Trust V (“Intervest V”), (collectively, the “Intervest Trusts”; and together with Ozark Trusts, the “Trusts”) and, indirectly through the Bank, a subsidiary engaged in the development of real estate, a subsidiary that owns private aircraft and various other entities that hold foreclosed assets or tax credits or engage in other activities. The Company and Bank are subject to the regulation of certain federal and state agencies and undergo periodic examinations by those regulatory authorities. The consolidated financial statements include the accounts of the Company, the Bank, the real estate subsidiary, the aircraft subsidiary and certain of those various other entities in accordance with accounting principles generally accepted in the United States (“GAAP”). Significant intercompany transactions and amounts have been eliminated in consolidation.
	At March 31, 2015, the Company had 165 offices, including 81 in Arkansas, 28 in Georgia, 21 in Texas, 16 in North Carolina, 11 in Florida, three in Alabama, two offices each in South Carolina and New York and one office in California.

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	2	Basis of Presentation
	The accompanying consolidated financial statements have been prepared by the Company, without audit, pursuant to the rules and regulations of the Securities and Exchange Commission (“SEC”) in Article 10 of Regulation S-X and in accordance with the instructions to Form 10-Q and GAAP for interim financial information. Certain information, accounting policies and footnote disclosures normally included in complete financial statements prepared in accordance with GAAP have been condensed or omitted in accordance with such rules and regulations. These consolidated financial statements should be read in conjunction with the audited consolidated financial statements and notes thereto included in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.
	The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Actual results could differ from those estimates. In the opinion of management, all adjustments considered necessary, consisting of normal recurring items, have been included for a fair presentation of the accompanying consolidated financial statements. Operating results for the three months ended March 31, 2015 are not necessarily indicative of the results that may be expected for the full year or future periods.
	On June 23, 2014, the Company completed a two-for-one stock split in the form of a stock dividend by issuing one share of common stock for each share of such stock outstanding on June 13, 2014. All share and per share information in the consolidated financial statements and the notes to the consolidated financial statements has been adjusted to give effect to this stock split.
	Certain reclassifications of prior period amounts have been made to conform with the current period presentation. These reclassifications had no impact on previously reported net income. Additionally, during the fourth quarter of 2014, the Bank and the Federal Deposit Insurance Corporation (“FDIC”) entered into agreements terminating the loss share agreements for all seven of the Company’s FDIC-assisted acquisitions. As a result of entering these termination agreements, the Company reclassified its loans previously reported as covered by FDIC loss share to purchased loans for all periods presented. Additionally, the Company has reclassified all interest income in loans previously reported as covered by FDIC loss share to interest income on purchased loans for all periods presented.

Acquisitions

Acquisitions	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Acquisitions	3	Acquisitions
	Intervest Bancshares Corporation
	On February 10, 2015, the Company completed its previously announced acquisition of Intervest Bancshares Corporation (“Intervest”), and its wholly-owned bank subsidiary Intervest National Bank, for an aggregate of 6,637,243 shares of its common stock (plus cash in lieu of fractional shares) in a transaction valued at approximately $238.5 million. The acquisition of Intervest provided the Company with a banking office in New York City and expanded its service area in Florida by adding five banking offices in Clearwater, Florida and one office in South Pasadena, Florida.
	The following table provides a summary of the assets acquired and liabilities assumed as recorded by Intervest, the preliminary estimates of the fair value adjustments necessary to adjust those acquired assets and assumed liabilities to estimated fair value, and the preliminary estimates of the resultant fair values of those assets and liabilities as recorded by the Company. As provided for under GAAP, management has up to 12 months following the date of acquisition to finalize the fair values of the acquired assets and assumed liabilities. Once management has finalized the fair values of acquired assets and assumed liabilities within this 12-month period, management considers such values to be the day 1 fair values (“Day 1 Fair Values”). The preliminary fair value adjustments and the preliminary resultant fair values shown in the following table continue to be evaluated by management and may be subject to further adjustment.
			February 10, 2015
			As Recorded			Preliminary				As Recorded
			by			Fair Value				by the
			Intervest			Adjustments(1)				Company(1)
			(Dollars in thousands)
	Assets acquired:
	Cash, due from banks and interest earning deposits		$	274,343		$	0			$	274,343
	Investment securities			21,495			321		a		21,816
	Loans			1,108,439			(33,868	)	b		1,074,571
	Allowance for loan losses			(25,208	)		25,208		b		0
	Premises and equipment			4,357			2,256		c		6,613
	Foreclosed assets			2,350			(1,710	)	d		640
	Accrued interest receivable and other assets			34,076			(4,091	)	e		29,985
	Core deposit intangible asset			0			4,595		f		4,595
	Deferred income taxes			11,758			8,082		g		19,840
	Total assets acquired			1,431,610			793				1,432,403
	Liabilities assumed:
	Deposits			1,162,437			22,211		h		1,184,648
	Subordinated debentures			56,702			(4,463	)	i		52,239
	Accrued interest payable and other liabilities			3,608			358		j		3,966
	Total liabilities assumed			1,222,747			18,106				1,240,853
	Net assets acquired		$	208,863		$	(17,313	)			191,550
	Consideration paid:
	Cash in lieu of fractional shares										(7	)
	Stock										(238,476	)
	Total consideration paid										(238,483	)
	Goodwill									$	46,933
	(1)	The acquisition of Intervest closed on February 10, 2015. Accordingly, each of the fair value adjustments shown are preliminary estimates of the purchase accounting adjustments. Management is continuing to evaluate each of these fair value adjustments and may revise one or more of such fair value adjustments in future periods based on this continuing evaluation. To the extent that any of these preliminary fair value adjustments are revised in future periods, the resultant fair values and the amount of goodwill could change.
	Explanation of preliminary fair value adjustments
	a-		Adjustment reflects the fair value adjustment based on the pricing of the acquired investment securities portfolio.
	b-		Adjustment reflects the fair value adjustment based on the evaluation of the acquired loan portfolio and to eliminate the recorded allowance for loan losses.
	c-		Adjustment reflects the fair value adjustment based on the evaluation of the premises and equipment acquired.
	d-		Adjustment reflects the fair value adjustment based on the evaluation of the acquired foreclosed assets.
	e-		Adjustment reflects the fair value adjustment based on the evaluation of accrued interest receivable and other assets.
	f-		Adjustment reflects the fair value adjustment for the core deposit intangible asset recorded as a result of the acquisition.
	g-		This adjustment reflects the differences in the carrying values of acquired assets and assumed liabilities for financial reporting purposes and their basis for federal income tax purposes.
	h-		Adjustment reflects the fair value adjustment based on the evaluation of the acquired deposits.
	i-		Adjustment reflects the fair value adjustment of these assumed liabilities based on a valuation of such instruments by an independent, third party valuation firm.
	j-		Adjustment reflects the amount needed to adjust other liabilities to estimated fair value and to record certain liabilities directly attributable to the Intervest acquisition.
	Goodwill of $46.9 million, which is the excess of the merger consideration over the fair value of net assets acquired, was recorded in the Intervest acquisition and is the result of expected operational synergies, expansion of full service banking in New York City and other factors. This goodwill is not expected to be deductible for tax purposes. To the extent that management revises any of the above fair value adjustments as a result of its continuing evaluation, the amount of goodwill recorded in the Intervest acquisition could change.
	The Company’s consolidated results of operations include the operating results for Intervest beginning February 11, 2015 through the end of the reporting period. Intervest contributed $8.9 million of net interest income and $4.8 million of net income during the three months ended March 31, 2015.
	The following unaudited supplemental pro forma information is presented to show the estimated results assuming Intervest was acquired as of the beginning of the earliest period presented, adjusted for estimated potential costs savings. These unaudited pro forma results are not necessarily indicative of the operating results that the Company would have achieved had it completed the acquisition as of January 1, 2014 and should not be considered as representative of future operating results.
			Three Months Ended
			March 31,
			2015			2014
			(Dollars in thousands,
			except per share amounts)
	Net interest income – pro forma (unaudited)		$	90,345		$	67,947
	Net income – pro forma (unaudited)		$	43,924		$	30,504
	Diluted earnings per common share – pro forma (unaudited)		$	0.5		$	0.38
	Summit Bancorp, Inc.
	On May 16, 2014, the Company completed the acquisition of Summit Bancorp, Inc. (“Summit”) and Summit Bank, its wholly-owned bank subsidiary, for an aggregate of $42.5 million in cash and 5,765,846 shares of its common stock. The acquisition of Summit expanded its service area in Central, South and Western Arkansas by adding 23 banking locations and one loan production office in nine Arkansas counties. During the second quarter of 2014, the Company closed one of the banking offices and the one loan production office acquired in the Summit acquisition. During the fourth quarter of 2014, the Company closed seven additional banking offices, including five that were acquired from Summit, in markets where the Company had excess branches as a result of the Summit acquisition. Goodwill of $73.4 million, which is the excess of the merger consideration over the fair value of net assets acquired, was recorded in the Summit acquisition and is the result of expected operational synergies and other factors. This goodwill is not expected to be deductible for tax purposes.
	Bancshares, Inc.
	On March 5, 2014, the Company completed its acquisition of Bancshares, Inc. (“Bancshares”) and OMNIBANK, N.A., its wholly-owned bank subsidiary, for an aggregate of $21.5 million in cash. The Company recognized a bargain purchase gain of $4.7 million during the first quarter of 2014 as a result of the Bancshares acquisition. The acquisition of Bancshares expanded the Company’s service area in South Texas by adding three offices in Houston and one office each in Austin, Cedar Park, Lockhart, and San Antonio.

Earnings_Per_Common_Share_EPS

Earnings Per Common Share ("EPS")	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Common Share ("EPS")	4	Earnings Per Common Share (“EPS”)
	Basic EPS is computed by dividing net income available to common stockholders by the weighted-average number of common shares outstanding. Diluted EPS is computed by dividing net income available to common stockholders by the weighted-average number of common shares outstanding after consideration of the dilutive effect, if any, of outstanding common stock options using the treasury stock method. At March 31, 2015, options to purchase 535,000 shares of the Company’s common stock at a weighted-average exercise price of $36.05 were outstanding but not included in the computation of diluted EPS because the options exercise price was greater than the average market price of the common shares and inclusion would have been antidilutive. No options to purchase shares of common stock for the three months ended March 31, 2014 were excluded from the diluted EPS calculations as all options were dilutive.
	The following table presents the computation of basic and diluted EPS for the periods indicated.
			Three Months Ended
			March 31,
			2015		2014
			(In thousands, except per
			share amounts)
	Numerator:
	Distributed earnings allocated to common stock		$	10,413	$	8,108
	Undistributed earnings allocated to common stock			29,481		17,168
	Net income available to common stock		$	39,894	$	25,276
	Denominator:
	Denominator for basic EPS – weighted-average common shares			83,699		73,802
	Effect of dilutive securities – stock options			710		692
	Denominator for diluted EPS – weighted-average common shares and assumed conversions			84,409		74,494
	Basic EPS		$	0.48	$	0.34
	Diluted EPS		$	0.47	$	0.34

Investment_Securities

Investment Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Investment Securities	5	Investment Securities
	At March 31, 2015 and 2014 and at December 31, 2014, the Company classified all of its investment securities portfolio as AFS. Accordingly, investment securities are stated at estimated fair value in the consolidated financial statements with unrealized gains and losses, net of related income tax, reported as a separate component of stockholders’ equity and included in accumulated other comprehensive income (loss).
	The following table presents the amortized cost and estimated fair value of investment securities AFS as of the dates indicated. The Company’s investment in the “CRA qualified investment fund” includes shares held in a mutual fund that qualifies under the Community Reinvestment Act of 1977 for community reinvestment purposes. The Company’s holdings of equity securities in Federal Home Loan Bank of Dallas (“FHLB”) and First National Banker’s Bankshares, Inc. (“FNBB”) do not have readily determinable fair values and are carried at cost.
			Amortized			Gross		Gross			Estimated
			Cost			Unrealized		Unrealized			Fair Value
						Gains		Losses
			(Dollars in thousands)
	March 31, 2015:
	Obligations of state and political subdivisions		$	496,251		$	16,203	$	(247	)	$	512,207
	U.S. Government agency securities			252,728			7,503		(256	)		259,975
	Corporate obligations			622			0		0			622
	CRA qualified investment fund			1,022			6		0			1,028
	FHLB and FNBB equity securities			10,443			0		0			10,443
	Total		$	761,066		$	23,712	$	(503	)	$	784,275
	December 31, 2014:
	Obligations of state and political subdivisions		$	555,335		$	18,267	$	(393	)	$	573,209
	U.S. Government agency securities			245,854			6,144		(765	)		251,233
	Corporate obligations			654			0		0			654
	FHLB and FNBB equity securities			14,225			0		0			14,225
	Total		$	816,068		$	24,411	$	(1,158	)	$	839,321
	March 31, 2014:
	Obligations of state and political subdivisions		$	447,368		$	10,010	$	(4,630	)	$	452,748
	U.S. Government agency securities			219,836			3,526		(3,622	)		219,740
	Corporate obligations			686			0		0			686
	FHLB and FNBB equity securities			14,487			0		0			14,487
	Total		$	682,377		$	13,536	$	(8,252	)	$	687,661
	The following table shows estimated fair value of investment securities AFS having gross unrealized losses and the amount of such unrealized losses, aggregated by investment category and length of time that individual investment securities have been in a continuous unrealized loss position, as of the dates indicated.
			Less than 12 Months					12 Months or More					Total
			Estimated			Unrealized		Estimated			Unrealized		Estimated		Unrealized
			Fair Value			Losses		Fair Value			Losses		Fair Value		Losses
			(Dollars in thousands)
	March 31, 2015:
	Obligations of state and political subdivisions		$	39,112		$	189	$	3,437		$	58	$	42,549	$	247
	U.S. Government agency securities			23,451			171		7,241			85		30,692		256
	Total temporarily impaired securities		$	62,563		$	360	$	10,678		$	143	$	73,241	$	503
	December 31, 2014:
	Obligations of state and political subdivisions		$	29,174		$	75	$	34,414		$	318	$	63,588	$	393
	U.S. Government agency securities			9,630			25		47,626			740		57,256		765
	Total temporarily impaired securities		$	38,804		$	100	$	82,040		$	1,058	$	120,844	$	1,158
	March 31, 2014:
	Obligations of state and political subdivisions		$	51,961		$	2,048	$	47,890		$	2,582	$	99,851	$	4,630
	U.S. Government agency securities			69,783			3,582		1,038			40		70,821		3,622
	Total temporarily impaired securities		$	121,744		$	5,630	$	48,928		$	2,622	$	170,672	$	8,252
	In evaluating the Company’s unrealized loss positions for other-than-temporary impairment of its investment securities portfolio, management considers the credit quality of the issuer, the nature and cause of the unrealized loss, the severity and duration of the impairments and other factors. At March 31, 2015 management determined the unrealized losses were the result of fluctuations in interest rates and did not reflect deteriorations of the credit quality of the investments. Accordingly, management considers these unrealized losses to be temporary in nature. The Company does not have the intent to sell these investment securities with unrealized losses and, more likely than not, will not be required to sell these investment securities before fair value recovers to amortized cost.
	The following table shows the amortized cost and estimated fair value of investment securities AFS by maturity or estimated date of repayment as of the date indicated.
			March 31, 2015
	Maturity or		Amortized			Estimated
	Estimated Repayment		Cost			Fair Value
			(Dollars in thousands)
	One year or less		$	37,328		$	38,391
	After one year to five years			139,542			142,725
	After five years to ten years			187,370			192,169
	After ten years			396,826			410,990
	Total		$	761,066		$	784,275
	For purposes of this maturity distribution, all investment securities AFS are shown based on their contractual maturity date or estimated date of repayment, except (i) FHLB and FNBB equity securities and the CRA qualified investment fund with no contractual maturity date are shown in the longest maturity category and (ii) U.S. Government agency securities and municipal housing authority securities backed by residential mortgages are allocated among various maturities based on an estimated repayment schedule utilizing Bloomberg median prepayment speeds or other estimates of prepayment speeds and interest rate levels at the measurement date. Expected maturities will differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties.
	The following table is a summary of sales activities in the Company’s investment securities AFS for the periods indicated.
			Three Months Ended
			March 31,
			2015			2014
			(Dollars in thousands)
	Sales proceeds		$	30,117		$	1,224
	Gross realized gains		$	2,535		$	5
	Gross realized losses			(1	)		0
	Net gains on investment securities		$	2,534		$	5

Allowance_for_Loan_and_Lease_L

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators	3 Months Ended
	Mar. 31, 2015
Text Block [Abstract]
Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators	6	Allowance for Loan and Lease Losses (“ALLL”) and Credit Quality Indicators
	Allowance for Loan and Lease Losses
	The following table is a summary of activity within the ALLL for the periods indicated.
			Three Months Ended
			March 31,
			2015			2014
			(Dollars in thousands)
	Beginning balance		$	52,918		$	42,945
	Non-purchased loans and leases charged off			(4,079	)		(920	)
	Recoveries of non-purchased loans and leases previously charged off			308			736
	Net non-purchased loans and leases charged off			(3,771	)		(184	)
	Purchased loans charged off, net			(1,315	)		(204	)
	Net charge-offs – total loans and leases			(5,086	)		(388	)
	Provision for loan and lease losses:
	Non-purchased loans and leases			5,000			1,100
	Purchased loans			1,315			204
	Total provision			6,315			1,304
	Ending balance		$	54,147		$	43,861
	As of March 31, 2015, the Company had identified purchased loans where the expected performance had deteriorated from management’s performance expectations established in conjunction with the determination of the Day 1 Fair Values or where current information indicates it is probable that the Company will not be able to collect all amounts according to the contractual terms thereon. As a result, the Company recorded partial charge-offs totaling $1.3 million during the first quarter of 2015 and $0.2 million during the first quarter of 2014. The Company also recorded provision for loan and lease losses of $1.3 million during the first quarter of 2015 and $0.2 million during the first quarter of 2014. At March 31, 2015, the Company had $14.1 million of impaired purchased loans compared to $29.3 million at March 31, 2014 and $14.0 million at December 31, 2014.
	The following table is a summary of the Company’s ALLL for the periods indicated.
			Beginning			Charge-offs			Recoveries		Provision			Ending
			Balance											Balance
			(Dollars in thousands)
	Three months ended March 31, 2015:
	Real estate:
	Residential 1-4 family		$	5,482		$	(529	)	$	11	$	693		$	5,657
	Non-farm/non-residential			17,190			(205	)		12		769			17,766
	Construction/land development			15,960			(302	)		37		1,885			17,580
	Agricultural			2,558			(13	)		0		(19	)		2,526
	Multifamily residential			2,147			0			0		276			2,423
	Commercial and industrial			4,873			(2,447	)		16		859			3,301
	Consumer			818			(45	)		21		30			824
	Direct financing leases			2,989			(186	)		6		449			3,258
	Other			901			(352	)		205		58			812
	Purchased loans			0			(1,315	)		0		1,315			0
	Total		$	52,918		$	(5,394	)	$	308	$	6,315		$	54,147
	Year ended December 31, 2014:
	Real estate:
	Residential 1-4 family		$	4,701		$	(577	)	$	135	$	1,223		$	5,482
	Non-farm/non-residential			13,633			(1,357	)		33		4,881			17,190
	Construction/land development			12,306			(638	)		11		4,281			15,960
	Agricultural			3,000			(214	)		14		(242	)		2,558
	Multifamily residential			2,504			0			0		(357	)		2,147
	Commercial and industrial			2,855			(720	)		808		1,930			4,873
	Consumer			917			(222	)		80		43			818
	Direct financing leases			2,266			(602	)		49		1,276			2,989
	Other			763			(793	)		266		665			901
	Purchased loans			0			(3,215	)		0		3,215			0
	Total		$	42,945		$	(8,338	)	$	1,396	$	16,915		$	52,918
	Three months ended March 31, 2014:
	Real estate:
	Residential 1-4 family		$	4,701		$	(199	)	$	22	$	98		$	4,622
	Non-farm/non-residential			13,633			(73	)		3		450			14,013
	Construction/land development			12,306			0			8		514			12,828
	Agricultural			3,000			(15	)		5		28			3,018
	Multifamily residential			2,504			0			0		(75	)		2,429
	Commercial and industrial			2,855			(374	)		628		(371	)		2,738
	Consumer			917			(41	)		18		(63	)		831
	Direct financing leases			2,266			(146	)		6		312			2,438
	Other			763			(72	)		46		207			944
	Purchased loans			0			(204	)		0		204			0
	Total		$	42,945		$	(1,124	)	$	736	$	1,304		$	43,861
	The following table is a summary of the Company’s ALLL and recorded investment in non-purchased loans and leases of the dates indicated.
			ALLL								Non-Purchased Loans and Leases
		ALLL for			ALLL for			Total		Individually			All Other		Total Loans
		Individually			All Other			ALLL		Evaluated			Loans and		and Leases
		Evaluated			Loans and					Impaired			Leases
		Impaired			Leases					Loans and
		Loans and								Leases
		Leases
		(Dollars in thousands)
March 31, 2015:
Real estate:
Residential 1-4 family		$	295		$	5,362		$	5,657	$	2,509		$	301,326	$	303,835
Non-farm/non-residential			10			17,756			17,766		538			1,574,413		1,574,951
Construction/land development			2			17,578			17,580		9,413			1,650,924		1,660,337
Agricultural			0			2,526			2,526		305			48,879		49,184
Multifamily residential			0			2,423			2,423		0			228,973		228,973
Commercial and industrial			53			3,248			3,301		131			252,947		253,078
Consumer			3			821			824		33			24,836		24,869
Direct financing leases			0			3,258			3,258		0			126,326		126,326
Other			0			812			812		9			89,543		89,552
Total		$	363		$	53,784		$	54,147	$	12,938		$	4,298,167	$	4,311,105
December 31, 2014:
Real estate:
Residential 1-4 family		$	356		$	5,126		$	5,482	$	2,734		$	280,519	$	283,253
Non-farm/non-residential			18			17,172			17,190		2,507			1,501,034		1,503,541
Construction/land development			68			15,892			15,960		14,304			1,397,534		1,411,838
Agricultural			6			2,552			2,558		365			46,870		47,235
Multifamily residential			0			2,147			2,147		0			211,156		211,156
Commercial and industrial			644			4,229			4,873		623			287,084		287,707
Consumer			3			815			818		34			25,635		25,669
Direct financing leases			0			2,989			2,989		0			115,475		115,475
Other			0			901			901		8			93,988		93,996
Total		$	1,095		$	51,823		$	52,918	$	20,575		$	3,959,295	$	3,979,870
March 31, 2014:
Real estate:
Residential 1-4 family		$	385		$	4,237		$	4,622	$	3,811		$	248,977	$	252,788
Non-farm/non-residential			29			13,984			14,013		1,627			1,142,856		1,144,483
Construction/land development			2			12,826			12,828		325			795,801		796,126
Agricultural			243			2,775			3,018		817			43,091		43,908
Multifamily residential			0			2,429			2,429		0			195,332		195,332
Commercial and industrial			624			2,114			2,738		626			137,038		137,664
Consumer			3			828			831		48			23,721		23,769
Direct financing leases			0			2,438			2,438		0			92,856		92,856
Other			0			944			944		10			91,567		91,577
Total		$	1,286		$	42,575		$	43,861	$	7,264		$	2,771,239	$	2,778,503
The following table is a summary of impaired non-purchased loans and leases as of and for the three months ended March 31, 2015.
		Principal			Net			Principal		Specific			Weighted
		Balance			Charge-offs			Balance,		ALLL			Average
					to Date			Net of					Carrying
								Charge-offs					Value – Three
													Months Ended
													March 31,
													2015
		(Dollars in thousands)
Impaired loans and leases for which there is a related ALLL:
Real estate:
Residential 1-4 family		$	3,123		$	(1,814	)	$	1,309	$	295		$	1,399
Non-farm/non-residential			184			(142	)		42		10			292
Construction/land development			38			(22	)		16		2			2,064
Agricultural			0			0			0		0			46
Commercial and industrial			632			(631	)		1		53			0
Consumer			40			(23	)		17		3			271
Other			0			0			0		0			18
Total impaired loans and leases with a related ALLL			4,017			(2,632	)		1,385		363			4,090
Impaired loans and leases for which there is not a related ALLL:
Real estate:
Residential 1-4 family			1,379			(179	)		1,200		0			1,223
Non-farm/non-residential			633			(137	)		496		0			1,231
Construction/land development			9,500			(102	)		9,398		0			9,796
Agricultural			507			(202	)		305		0			288
Multifamily residential			133			(133	)		0		0			0
Commercial and industrial			290			(159	)		131		0			106
Consumer			20			(5	)		15		0			15
Other			8			0			8		0			8
Total impaired loans and leases without a related ALLL			12,470			(917	)		11,553		0			12,667
Total impaired loans and leases		$	16,487		$	(3,549	)	$	12,938	$	363		$	16,757
The following table is a summary of impaired non-purchased loans and leases as of and for the year ended December 31, 2014.
		Principal			Net			Principal		Specific			Weighted
		Balance			Charge-offs			Balance,		ALLL			Average
					to Date			Net of					Carrying
								Charge-offs					Value – Year
													Ended
													December 31,
													2014
		(Dollars in thousands)
Impaired loans and leases for which there is a related ALLL:
Real estate:
Residential 1-4 family		$	3,163		$	(1,674	)	$	1,489	$	356		$	1,457
Non-farm/non-residential			762			(220	)		542		18			211
Construction/land development			4,656			(545	)		4,111		68			1,040
Agricultural			105			(12	)		93		6			217
Commercial and industrial			1,233			(691	)		542		644			554
Consumer			41			(23	)		18		3			20
Total impaired loans and leases with a related ALLL			9,960			(3,165	)		6,795		1,095			3,499
Impaired loans and leases for which there is not a related ALLL:
Real estate:
Residential 1-4 family			1,373			(128	)		1,245		0			1,581
Non-farm/non-residential			2,676			(711	)		1,965		0			1,988
Construction/land development			10,378			(185	)		10,193		0			7,600
Agricultural			474			(202	)		272		0			383
Multifamily residential			133			(133	)		0		0			123
Commercial and industrial			264			(183	)		81		0			75
Consumer			81			(65	)		16		0			18
Other			8			0			8		0			8
Total impaired loans and leases without a related ALLL			15,387			(1,607	)		13,780		0			11,776
Total impaired loans and leases		$	25,347		$	(4,772	)	$	20,575	$	1,095		$	15,275
The following table is a summary of impaired non-purchased loans and leases as of and for the three months ended March 31, 2014.
		Principal			Net			Principal		Specific			Weighted
		Balance			Charge-offs			Balance,		ALLL			Average
					to Date			Net of					Carrying
								Charge-offs					Value – Three
													Months Ended
													March 31,
													2014
		(Dollars in thousands)
Impaired loans and leases for which there is a related ALLL:
Real estate:
Residential 1-4 family		$	3,164		$	(1,726	)	$	1,438	$	385		$	1,677
Non-farm/non-residential			188			(127	)		61		29			53
Construction/land development			38			(22	)		16		2			16
Agricultural			360			(12	)		348		243			409
Commercial and industrial			1,368			(803	)		565		624			588
Consumer			103			(80	)		23		3			23
Other			0			0			0		0			8
Total impaired loans and leases with a related ALLL			5,221			(2,770	)		2,451		1,286			2,774
Impaired loans and leases for which there is not a related ALLL:
Real estate:
Residential 1-4 family			2,845			(472	)		2,373		0			2,252
Non-farm/non-residential			2,702			(1,136	)		1,566		0			1,840
Construction/land development			390			(81	)		309		0			264
Agricultural			513			(44	)		469		0			441
Multifamily residential			133			(133	)		0		0			0
Commercial and industrial			220			(159	)		61		0			68
Consumer			34			(9	)		25		0			26
Other			30			(20	)		10		0			10
Total impaired loans and leases without a related ALLL			6,867			(2,054	)		4,813		0			4,901
Total impaired loans and leases		$	12,088		$	(4,824	)	$	7,264	$	1,286		$	7,675
Management has determined that certain of the Company’s impaired non-purchased loans and leases do not require any specific allowance at March 31, 2015 and 2014 or at December 31, 2014 because (i) management’s analysis of such individual loans and leases resulted in no impairment or (ii) all identified impairment on such loans and leases has previously been charged off.
Interest income on impaired non-purchased loans and leases is recognized on a cash basis when and if actually collected. Total interest income recognized on impaired non-purchased loans and leases for the three months ended March 31, 2015 and 2014 and for the year ended December 31, 2014 was not material.
Credit Quality Indicators
Non-Purchased Loans and Leases
The following table is a summary of credit quality indicators for the Company’s non-purchased loans and leases as of the dates indicated.
		Satisfactory			Moderate			Watch		Substandard			Total
		(Dollars in thousands)
March 31, 2015:
Real estate:
Residential 1-4 family (1)		$	293,140		$	0		$	4,456	$	6,239		$	303,835
Non-farm/non-residential			1,356,456			158,588			53,874		6,033			1,574,951
Construction/land development			1,433,497			203,405			11,049		12,386			1,660,337
Agricultural			23,663			13,974			9,293		2,254			49,184
Multifamily residential			187,966			37,686			1,663		1,658			228,973
Commercial and industrial			180,448			68,809			2,403		1,418			253,078
Consumer (1)			24,243			0			369		257			24,869
Direct financing leases			125,845			354			75		52			126,326
Other (1)			84,596			4,716			221		19			89,552
Total		$	3,709,854		$	487,532		$	83,403	$	30,316		$	4,311,105
December 31, 2014:
Real estate:
Residential 1-4 family (1)		$	271,576		$	0		$	4,082	$	7,595		$	283,253
Non-farm/non-residential			1,300,582			142,688			53,863		6,408			1,503,541
Construction/land development			1,190,005			192,046			11,135		18,652			1,411,838
Agricultural			22,446			12,375			10,226		2,188			47,235
Multifamily residential			171,806			37,886			713		751			211,156
Commercial and industrial			208,054			59,967			18,310		1,376			287,707
Consumer (1)			25,267			0			141		261			25,669
Direct financing leases			114,586			715			117		57			115,475
Other (1)			89,364			4,312			286		34			93,996
Total		$	3,393,686		$	449,989		$	98,873	$	37,322		$	3,979,870
March 31, 2014:
Real estate:
Residential 1-4 family (1)		$	244,259		$	0		$	2,449	$	6,080		$	252,788
Non-farm/non-residential			954,057			130,787			53,658		5,981			1,144,483
Construction/land development			613,474			155,254			23,254		4,144			796,126
Agricultural			21,228			9,914			9,747		3,019			43,908
Multifamily residential			164,062			29,625			389		1,256			195,332
Commercial and industrial			103,039			31,434			1,642		1,549			137,664
Consumer (1)			23,203			0			220		346			23,769
Direct financing leases			91,927			881			0		48			92,856
Other (1)			89,181			2,253			113		30			91,577
Total		$	2,304,430		$	360,148		$	91,472	$	22,453		$	2,778,503
-1	The Company does not risk rate its residential 1-4 family loans, its consumer loans, and certain “other” loans. However, for purposes of the above table, the Company considers such loans to be (i) satisfactory – if they are performing and less than 30 days past due, (ii) watch – if they are performing and 30 to 89 days past due or (iii) substandard – if they are nonperforming or 90 days or more past due.
The following categories of credit quality indicators are used by the Company.
Satisfactory – Loans and leases in this category are considered to be a satisfactory credit risk and are generally considered to be collectible in full.
Moderate – Loans and leases in this category are considered to be a marginally satisfactory credit risk and are generally considered to be collectible in full.
Watch – Loans and leases in this category are presently protected from apparent loss; however, weaknesses exist which could cause future impairment of repayment of principal or interest.
Substandard – Loans and leases in this category are characterized by deterioration in quality exhibited by a number of weaknesses requiring corrective action and posing risk of some loss.
The following table is an aging analysis of past due non-purchased loans and leases as of the dates indicated.
		30-89 Days			90 Days			Total		Current (3)			Total
		Past Due (1)			or More (2)			Past Due
		(Dollars in thousands)
March 31, 2015:
Real estate:
Residential 1-4 family		$	5,161		$	1,618		$	6,779	$	297,056		$	303,835
Non-farm/non-residential			4,276			376			4,652		1,570,299			1,574,951
Construction/land development			229			9,414			9,643		1,650,694			1,660,337
Agricultural			1,685			305			1,990		47,194			49,184
Multifamily residential			0			0			0		228,973			228,973
Commercial and industrial			1,862			198			2,060		251,018			253,078
Consumer			394			27			421		24,448			24,869
Direct financing leases			41			52			93		126,233			126,326
Other			163			8			171		89,381			89,552
Total		$	13,811		$	11,998		$	25,809	$	4,285,296		$	4,311,105
December 31, 2014:
Real estate:
Residential 1-4 family		$	6,352		$	1,536		$	7,888	$	275,365		$	283,253
Non-farm/non-residential			2,708			1,445			4,153		1,499,388			1,503,541
Construction/land development			3,520			12,881			16,401		1,395,437			1,411,838
Agricultural			1,680			304			1,984		45,251			47,235
Multifamily residential			0			0			0		211,156			211,156
Commercial and industrial			586			94			680		287,027			287,707
Consumer			161			55			216		25,453			25,669
Direct financing leases			39			54			93		115,382			115,475
Other			58			12			70		93,926			93,996
Total		$	15,104		$	16,381		$	31,485	$	3,948,385		$	3,979,870
March 31, 2014:
Real estate:
Residential 1-4 family		$	3,167		$	2,108		$	5,275	$	247,513		$	252,788
Non-farm/non-residential			647			1,376			2,023		1,142,460			1,144,483
Construction/land development			7,077			3,950			11,027		785,099			796,126
Agricultural			495			582			1,077		42,831			43,908
Multifamily residential			0			0			0		195,332			195,332
Commercial and industrial			891			16			907		136,757			137,664
Consumer			240			78			318		23,451			23,769
Direct financing leases			59			0			59		92,797			92,856
Other			17			9			26		91,551			91,577
Total		$	12,593		$	8,119		$	20,712	$	2,757,791		$	2,778,503
-1	Includes $0.6 million, $0.9 million and $0.6 million at March 31, 2015, December 31, 2014 and March 31, 2014, respectively, of loans and leases on nonaccrual status.
-2	All loans and leases greater than 90 days past due were on nonaccrual status at March 31, 2015 and 2014 and December 31, 2014.
-3	Includes $1.7 million, $0.4 million and $3.0 million of loans and leases on nonaccrual status at March 31, 2015, December 31, 2014 and March 31, 2014, respectively.
Purchased Loans
The following table is a summary of credit quality indicators for the Company’s purchased loans as of the dates indicated.
		Purchased Loans Without Evidence													Purchased Loans				Total
		of Credit Deterioration at Acquisition													With Evidence of				Purchased
															Credit Deterioration				Loans
															at Acquisition
		FV 33			FV 44			FV 55		FV 36			FV 77		FV 66		FV 88
		(Dollars in thousands)
March 31, 2015:
Real estate:
Residential 1-4 family		$	67,490		$	107,772		$	33,991	$	64,957		$	158	$	92,829	$	2,329	$	369,526
Non-farm/non-residential			227,184			759,926			135,766		4,353			256		151,342		7,000		1,285,827
Construction/land development			11,613			20,647			7,160		8,553			725		27,072		3,015		78,785
Agricultural			8,815			19,105			1,937		1,025			108		6,716		0		37,706
Multifamily residential			23,781			122,937			29,243		3,523			65		11,930		0		191,479
Total real estate			338,883			1,030,387			208,097		82,411			1,312		289,889		12,344		1,963,323
Commercial and industrial			15,608			20,960			4,539		7,042			23		8,059		462		56,693
Consumer			1,033			316			322		9,959			2		329		4		11,965
Other			4,623			3,689			310		763			0		798		0		10,183
Total		$	360,147		$	1,055,352		$	213,268	$	100,175		$	1,337	$	299,075	$	12,810	$	2,042,164
December 31, 2014:
Real estate:
Residential 1-4 family		$	73,196		$	81,840		$	30,180	$	71,687		$	151	$	96,752	$	1,899	$	355,705
Non-farm/non-residential			166,754			180,522			32,157		4,906			505		114,217		5,828		504,889
Construction/land development			21,803			26,858			4,312		13,708			0		28,497		4,598		99,776
Agricultural			10,444			25,187			2,409		1,525			0		8,331		92		47,988
Multifamily residential			22,731			11,646			1,971		884			67		4,823		312		42,434
Total real estate			294,928			326,053			71,029		92,710			723		252,620		12,729		1,050,792
Commercial and industrial			20,340			23,048			4,900		10,659			22		9,297		559		68,825
Consumer			1,605			272			420		12,538			3		426		4		15,268
Other			4,845			5,830			597		945			0		845		0		13,062
Total		$	321,718		$	355,203		$	76,946	$	116,852		$	748	$	263,188	$	13,292	$	1,147,947
March 31, 2014:
Real estate:
Residential 1-4 family		$	27,899		$	37,442		$	21,933	$	34,004		$	0	$	115,707	$	3,621	$	240,606
Non-farm/non-residential			59,720			102,836			32,160		2,701			0		140,933		14,534		352,884
Construction/land development			9,880			18,384			10,605		4,550			0		40,075		10,394		93,888
Agricultural			1,260			7,490			842		146			0		11,050		339		21,127
Multifamily residential			3,216			5,903			5,002		1,046			0		10,799		310		26,276
Total real estate			101,975			172,055			70,542		42,447			0		318,564		29,198		734,781
Commercial and industrial			10,766			14,526			5,138		2,648			0		12,975		130		46,183
Consumer			1,448			204			332		4,065			0		647		4		6,700
Other			1,204			2,835			529		200			0		1,056		0		5,824
Total		$	115,393		$	189,620		$	76,541	$	49,360		$	0	$	333,242	$	29,332	$	793,488
The following grades are used for purchased loans without evidence of credit deterioration at the date of acquisition.
FV 33 – Loans in this category are considered to be satisfactory with minimal credit risk and are generally considered collectible.
FV 44 – Loans in this category are considered to be marginally satisfactory with minimal to moderate credit risk and are generally considered collectible.
FV 55 – Loans in this category exhibit weakness and are considered to have elevated credit risk and elevated risk of repayment.
FV 36 – Loans in this category were not individually reviewed at the date of purchase and are assumed to have characteristics similar to the characteristics of the aggregate acquired portfolio.
FV 77 – Loans in this category have deteriorated since the date of purchase and are considered impaired.
The following grades are used for purchased loans with evidence of credit deterioration at the date of acquisition.
FV 66 – Loans in this category are performing in accordance with or exceeding management’s performance expectations established in conjunction with the determination of Day 1 Fair Values.
FV 88 – Loans in this category have deteriorated from management’s performance expectations established in conjunction with the determination of Day 1 Fair Values.
The Company had no allowance at March 31, 2015 and 2014 or December 31, 2014 for its (i) purchased loans without evidence of credit deterioration at the date of acquisition as management’s analysis of such individual loans resulted in no impairment or all identified impairment on such loans had been charged off, or (ii) purchased loans with evidence of credit deterioration at the date of acquisition as all such loans were performing in accordance with management’s expectations established in conjunction with the determination of the Day 1 Fair Values or all losses had been charged off on such loans whose performance had deteriorated from management’s expectations established in conjunction with the deterioration of the Day 1 Fair Values.
The following table is an aging analysis of past due purchased loans as of the dates indicated.
		30-89 Days			90 Days			Total		Current			Total
		Past Due			or More			Past Due					Purchased
													Loans
		(Dollars in thousands)
March 31, 2015:
Real estate:
Residential 1-4 family		$	7,783		$	8,064		$	15,847	$	353,679		$	369,526
Non-farm/non-residential			6,919			13,138			20,057		1,265,770			1,285,827
Construction/land development			1,623			4,336			5,959		72,826			78,785
Agriculture			249			167			416		37,290			37,706
Multifamily residential			5,375			504			5,879		185,600			191,479
Commercial and industrial			1,090			627			1,717		54,976			56,693
Consumer			148			98			246		11,719			11,965
Other			101			30			131		10,052			10,183
Total		$	23,288		$	26,964		$	50,252	$	1,991,912		$	2,042,164
December 31, 2014:
Real estate:
Residential 1-4 family		$	8,088		$	9,043		$	17,131	$	338,574		$	355,705
Non-farm/non-residential			8,907			12,439			21,346		483,543			504,889
Construction/land development			1,197			5,464			6,661		93,115			99,776
Agriculture			237			875			1,112		46,876			47,988
Multifamily residential			515			67			582		41,852			42,434
Commercial and industrial			863			751			1,614		67,211			68,825
Consumer			199			103			302		14,966			15,268
Other			0			31			31		13,031			13,062
Total		$	20,006		$	28,773		$	48,779	$	1,099,168		$	1,147,947
March 31, 2014:
Real estate:
Residential 1-4 family		$	11,457		$	15,258		$	26,715	$	213,891		$	240,606
Non-farm/non-residential			9,160			29,145			38,305		314,579			352,884
Construction/land development			1,979			16,537			18,516		75,372			93,888
Agriculture			1,129			1,547			2,676		18,451			21,127
Multifamily residential			0			5,139			5,139		21,137			26,276
Commercial and industrial			1,028			1,978			3,006		43,177			46,183
Consumer			179			179			358		6,342			6,700
Other			8			19			27		5,797			5,824
Total		$	24,940		$	69,802		$	94,742	$	698,746		$	793,488
At March 31, 2015 and 2014 and December 31, 2014, a portion of the Company’s purchased loans with evidence of credit deterioration at the date of acquisition were past due, including many that were 90 days or more past due. Such delinquencies were included in the Company’s performance expectations in determining the Day 1 Fair Values. Additionally, in accordance with GAAP, the Company continues to accrete into earnings income on such loans.

Income_Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Income Taxes	7	Income Taxes
	The following table is a summary of the types of temporary differences between the tax basis of assets and liabilities and their financial reporting amounts that give rise to deferred income tax assets and liabilities and their approximate tax effects as of the dates indicated.
			March 31,						December 31,
			2015			2014			2014
			(Dollars in thousands)
	Deferred tax assets:
	Allowance for loan and lease losses		$	20,625		$	16,842		$	20,324
	Differences in amounts reflected in the financial statements and income tax basis of purchased loans not previously covered by FDIC loss share agreements			32,962			18,453			20,444
	Differences in amounts reflected in the financial statements and income tax basis for deposits assumed in acquisitions			8,926			1,157			1,337
	Stock-based compensation			3,807			1,415			3,268
	Deferred compensation			2,069			1,888			1,991
	Foreclosed assets			4,471			4,831			3,503
	Deferred fees and costs on loans and leases			5,244			1,604			4,785
	Investment securities AFS			0			600			0
	Differences in amounts reflected in the financial statements and income tax basis of assets acquired and liabilities assumed in FDIC-assisted acquisitions			8,050			5,393			8,098
	Acquired net operating losses			13,569			13,180			13,332
	Other, net			1,958			2,130			2,568
	Total gross deferred tax assets			101,681			67,493			79,650
	Less valuation allowance			(474	)		(474	)		(474	)
	Net deferred tax asset			101,207			67,019			79,176
	Deferred tax liabilities:
	Accelerated depreciation on premises and equipment			19,114			17,954			18,653
	Investment securities AFS			7,675			0			7,692
	Acquired intangible assets			10,935			5,066			9,743
	Total gross deferred tax liabilities			37,724			23,020			36,088
	Net deferred tax assets		$	63,483		$	43,999		$	43,088
	Net operating losses were acquired in the Bancshares, Summit and Intervest acquisitions and the Company’s 2013 acquisition of The First National Bank of Shelby (“FNB Shelby”). The net operating losses from the Bancshares transaction total $15.7 million at March 31, 2015 and will expire at various dates from 2030 through 2034. The net operating losses acquired from the Summit transaction were utilized during 2014. The net operating losses acquired in the Intervest transaction totaled $6.3 million at March 31, 2015 and will expire at various dates from 2030 through 2035. The net operating losses from the FNB Shelby transaction totaled $20.0 million at March 31, 2015, of which $12.5 million will expire in 2032 and $7.5 million will expire in 2033.
	At March 31, 2015 and 2014 and December 31, 2014, the Company had a deferred tax valuation allowance of approximately $0.5 million to reflect its assessment that the realization of the benefits from the recovery of net operating losses are expected to be subject to Section 382 limitations.
	To the extent that additional information becomes available regarding the settlement or recovery of acquired net operating loss carryforwards or assets with built-in losses acquired in any of the Company’s previous acquisitions, management may be required to make adjustments to its deferred tax asset valuation allowance, which adjustments could affect goodwill or deferred income tax expense (benefit).

Supplemental_Data_for_Cash_Flo

Supplemental Data for Cash Flows	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Supplemental Data for Cash Flows	8	Supplemental Data for Cash Flows
	The following table provides supplemental cash flow information for the periods indicated.
			Three Months Ended
			March 31,
			2015		2014
			(Dollars in thousands)
	Cash paid during the period for:
	Interest		$	6,773	$	4,782
	Taxes			2,029		772
	Supplemental schedule of non-cash investing and financing activities:
	Net change in unrealized gains/losses on investment securities AFS			44		11,325
	Loans and premises and equipment transferred to foreclosed assets			6,746		2,205
	Unsettled AFS investment security purchases			0		2,267
	Common stock issued in merger and acquisition transaction			238,476		0

Guarantees_and_Commitments

Guarantees and Commitments	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Guarantees and Commitments	9	Guarantees and Commitments
	Outstanding standby letters of credit are contingent commitments issued by the Company generally to guarantee the performance of a customer in third party arrangements. The maximum amount of future payments the Company could be required to make under these guarantees at March 31, 2015 was $13.7 million. The Company holds collateral to support guarantees when deemed necessary. Collateralized commitments at March 31, 2015 totaled $13.5 million.
	At March 31, 2015, the Company had outstanding commitments to extend credit, excluding mortgage interest rate lock commitments, totaling $3.41 billion. The following table shows the contractual maturities of outstanding commitments to extend credit as of the date indicated.
	Contractual Maturities at March 31, 2015
	Maturity		Amount
	(Dollars in thousands)
	2015		$	168,610
	2016			338,819
	2017			1,746,740
	2018			808,907
	2019			92,812
	Thereafter			253,563
	Total		$	3,409,451

Subordinated_Debentures

Subordinated Debentures	3 Months Ended
	Mar. 31, 2015
Brokers and Dealers [Abstract]
Subordinated Debentures	10	Subordinated Debentures
	At March 31, 2015, the Company had the following issues of trust preferred securities and subordinated debentures owed to the Trusts.
			Subordinated		Unamortized			Carrying		Trust		Contractual
			Debentures		Discount at			Value of		Preferred		Interest
			Owed to		March 31,			Subordinated		Securities		Rate at
			Trust		2015			Debentures		of the		March 31,
								at March 31,		Trusts		2015
								2015
			(Dollars in thousands)
	Ozark II		$	14,434	$	0		$	14,434	$	14,000		3.18	%
	Ozark III			14,433		0			14,433		14,000		3.2
	Ozark IV			15,464		0			15,464		15,000		2.48
	Ozark V			20,619		0			20,619		20,000		1.87
	Intervest II			15,464		(701	)		14,763		15,000		3.22
	Intervest III			15,464		(811	)		14,653		15,000		3.06
	Intervest IV			15,464		(1,475	)		13,989		15,000		2.67
	Intervest V			10,310		(1,401	)		8,909		10,000		1.92
			$	121,652	$	(4,388	)	$	117,264	$	118,000
	On February 10, 2015, in conjunction with the Intervest acquisition, the Company acquired the Intervest Trusts with outstanding subordinated debentures totaling $56.7 million and related trust preferred securities totaling $55.0 million. On the date of such acquisition, the Company recorded the assumed subordinated debentures owed to the Intervest Trusts at estimated fair value of $52.2 million, based on an independent third party valuation, to reflect a current market interest rate for comparable obligations. The fair value adjustment of $4.5 million is being amortized, using a level-yield methodology over the estimated holding period of approximately eight years, as an increase in interest expense of the subordinated debentures owed to the Intervest Trusts. In addition to the subordinated debentures of the Intervest Trusts, the Company also acquired $1.7 million of trust common equity issued by the Intervest Trusts.
	The trust preferred securities issued by Intervest Trust II and the related subordinated debentures bear interest, adjustable quarterly, at 90-day London Interbank Offered Rates (“LIBOR”) plus 2.95% and contain a final maturity of September 17, 2033. The trust preferred securities issued by Intervest Trust III and the related subordinated debentures bear interest, adjustable quarterly, at 90-day LIBOR plus 2.79% and contain a final maturity of March 17, 2034. The trust preferred securities issued by Intervest Trust IV and the related subordinated debentures bear interest, adjustable quarterly, at 90-day LIBOR plus 2.40% and contain a final maturity of September 20, 2034. The trust preferred securities issued by Intervest Trust V and the related subordinated debentures bear interest, adjustable quarterly, at 90-day LIBOR plus 1.65% and contain a final maturity of December 15, 2036.
	At March 31, 2015, the Company had an aggregate of $121.7 million of subordinated debentures outstanding (with an aggregate carrying value of $117.3 million) and had an asset of $3.7 million representing its investment in the common equity issued by the Trusts. The sole assets of the Trusts are the adjustable rate debentures and the liabilities of the Trusts are the trust preferred securities. At March 31, 2015 and 2014, the Trusts had aggregate common equity of $3.7 million and $1.9 million, respectively, and did not have any restricted net assets. The Company has, through various contractual arrangements or by operation of law, fully and unconditionally guaranteed all obligations of the Trusts with respect to the trust preferred securities. Additionally, there are no restrictions on the ability of the Trusts to transfer funds to the Company in the form of cash dividends, loans or advances. The Company has the option to defer interest payments on the subordinated debentures from time to time for a period not to exceed five consecutive years. These trust preferred securities generally mature at or near the 30th anniversary date of each issuance. However, the trust preferred securities and related subordinated debentures may be prepaid at par, subject to regulatory approval.

StockBased_Compensation

Stock-Based Compensation	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Stock-Based Compensation	11	Stock-Based Compensation
	The Company has a nonqualified stock option plan for certain employees of the Company. This plan provides for the granting of nonqualified options to purchase shares of common stock in the Company. No option may be granted under this plan for less than the fair market value of the common stock, defined by the plan as the average of the highest reported asked price and the lowest reported bid price, on the date of the grant. The benefits or amounts that may be received by or allocated to any particular officer or employee of the Company under this plan will be determined in the sole discretion of the Company’s board of directors or its personnel and compensation committee. While the vesting period and the termination date for the employee plan options are determined when options are granted, all such employee options outstanding at March 31, 2015 were issued with a vesting date three years after issuance and an expiration date seven years after issuance.
	The Company also has a nonqualified stock option plan for non-employee directors. This plan permits each director who is not otherwise an employee of the Company, or any subsidiary, to receive options to purchase 2,000 shares of the Company’s common stock on the day following his or her election as a director of the Company at each annual meeting of stockholders and up to 2,000 shares upon election or appointment for the first time as a director of the Company. No option may be granted under this plan for less than the fair market value of the common stock, defined by the plan as the average of the highest reported asked price and the lowest reported bid price, on the date of the grant. These options are exercisable immediately and expire ten years after issuance.
	All shares issued in connection with options exercised under both the employee and non-employee director stock option plans are in the form of newly issued shares.
	The following table summarizes stock option activity for both the employee and non-employee director stock option plans for the period indicated.
			Options			Weighted-		Weighted-Average		Aggregate
						Average		Remaining		Intrinsic
						Exercise		Contractual Life		Value
						Price/Share		(in years)		(in thousands)
	Three Months Ended March 31, 2015:
	Outstanding – January 1, 2015			1,859,350		$	23.49
	Granted			0			0
	Exercised			(53,000	)		10.3
	Forfeited			(57,900	)		26.85
	Outstanding – March 31, 2015			1,748,450			23.78		5.4	$	22,990	(1)
	Fully vested and exercisable – March 31, 2015			365,600			13.55		4.5	$	8,549	(1)
	Expected to vest in future periods			1,246,680
	Fully vested and expected to vest –			1,612,280			23.13		5.4	$	22,254	(1)
	March 31, 2015 (2)
	-1	Based on closing price of $36.93 per share on March 31, 2015.
	-2	At March 31, 2015, the Company estimated that outstanding options to purchase 136,170 shares of its common stock would not vest and would be forfeited prior to their vesting date.
	Intrinsic value for stock options is defined as the amount by which the current market price of the underlying stock exceeds the exercise price. For those stock options where the exercise price exceeds the current market price of the underlying stock, the intrinsic value is zero. The total intrinsic value of options exercised during the three months ended March 31, 2015 and 2014 was $1.4 million and $3.9 million, respectively.
	No options to purchase shares of the Company’s stock were issued during the three months ended March 31, 2015 or 2014. Stock-based compensation expense for stock options included in non-interest expense was $0.6 million and $0.4 million for the three months ended March 31, 2015 and 2014, respectively. Total unrecognized compensation cost related to non-vested stock option grants was $4.3 million at March 31, 2015 is expected to be recognized over a weighted-average period of 2.2 years.
	The Company has a restricted stock and incentive plan whereby all officers and employees of the Company are eligible to receive awards of restricted stock or restricted stock units. The benefits or amounts that may be received by or allocated to any particular officer or employee of the Company under this plan will be determined in the sole discretion of the Company’s board of directors or its personnel and compensation committee. Shares of common stock issued under the plan may be shares of original issuance or shares held in treasury that have been reacquired by the Company. All restricted stock awards outstanding at March 31, 2015 were issued with a vesting date of three years after issuance.
	The following table summarizes non-vested restricted stock activity for the period indicated.
			Three Months Ended
			March 31, 2015
	Outstanding – January 1, 2015			444,700
	Granted			243,300
	Forfeited			(27,250	)
	Vested			0
	Outstanding – March 31, 2015			660,750
	Weighted-average grant date fair value		$	25.22
	The fair value of the restricted stock awards is amortized to compensation expense over the vesting period and is based on the market price of the Company’s common stock at the date of grant multiplied by the number of shares granted that are expected to vest. Stock-based compensation expense for restricted stock included in non-interest expense was $1.3 million and $0.9 million for the three months ended March 31, 2015 and 2014, respectively. Unrecognized compensation expense for non-vested restricted stock awards was $10.8 million at March 31, 2015 and is expected to be recognized over a weighted-average period of 2.4 years.

Fair_Value_Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements	12	Fair Value Measurements
	The Company measures certain of its assets and liabilities on a fair value basis using various valuation techniques and assumptions, depending on the nature of the asset or liability. Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants at the measurement date. Additionally, fair value is used either annually or on a non-recurring basis to evaluate certain assets and liabilities for impairment or for disclosure purposes. The Company had no liabilities that were accounted for at fair value at March 31, 2015 or 2014 or at December 31, 2014.
	The Company applies the following fair value hierarchy.
	Level 1		–		Quoted prices for identical instruments in active markets.
	Level 2		–		Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model-derived valuations whose inputs are observable.
	Level 3		–		Instruments whose inputs are unobservable.
	The following table sets forth the Company’s assets, as of the dates indicated, that are accounted for at fair value.
			Level 1			Level 2		Level 3		Total
			(Dollars in thousands)
	March 31, 2015:
	Investment securities AFS (1):
	Obligations of state and political subdivisions		$	0		$	493,140	$	19,067	$	512,207
	U.S. Government agency securities			0			259,975		0		259,975
	Corporate obligations			0			622		0		622
	CRA qualified investment fund			1,028			0		0		1,028
	Total investment securities AFS			1,028			753,737		19,067		773,832
	Impaired non-purchased loans and leases			0			0		12,574		12,574
	Impaired purchased loans			0			0		14,147		14,147
	Foreclosed assets			0			0		32,094		32,094
	Total assets at fair value		$	1,028		$	753,737	$	77,882	$	832,647
	December 31, 2014:
	Investment securities AFS (1):
	Obligations of state and political subdivisions		$	0		$	553,808	$	19,401	$	573,209
	U.S. Government agency securities			0			251,233		0		251,233
	Corporate obligations			0			654		0		654
	Total investment securities AFS			0			805,695		19,401		825,096
	Impaired non-purchased loans and leases			0			0		19,480		19,480
	Impaired purchased loans			0			0		14,040		14,040
	Foreclosed assets			0			0		37,775		37,775
	Total assets at fair value		$	0		$	805,695	$	90,696	$	896,391
	March 31, 2014:
	Investment securities AFS (1):
	Obligations of state and political subdivisions		$	0		$	434,201	$	18,547	$	452,748
	U.S. Government agency securities			0			219,740		0		219,740
	Corporate obligations			0			686		0		686
	Total investment securities AFS			0			654,627		18,547		673,174
	Impaired non-purchased loans and leases			0			0		5,978		5,978
	Impaired purchased loans			0			0		29,332		29,332
	Foreclosed assets			0			0		60,869		60,869
	Total assets at fair value		$	0		$	654,627	$	114,726	$	769,353
	-1	Does not include $10.4 million at March 31, 2015; $14.2 million at December 31, 2014 and $14.5 million at March 31, 2014 of FHLB and FNBB equity securities that do not have readily determinable fair values and are carried at cost.
	The following table presents information related to Level 3 non-recurring fair value measurements as of the date indicated.
	Description		Fair Value at		Technique	Unobservable Inputs
			March 31, 2015
	(Dollars in thousands)
	Impaired non-purchased loans and leases		$12,574		Third party appraisal(1) or discounted cash flows	1. Management discount based on underlying collateral characteristics and market conditions
						2. Life of loan
	Impaired purchased loans		$14,147		Third party appraisal(1) and/or discounted cash flows	1. Management discount based on underlying collateral characteristics and market conditions
						2. Life of loan
	Foreclosed assets		$32,094		Third party appraisal,(1) broker price opinions and/or discounted cash flows	1. Management discount based on asset characteristics and market conditions
						2. Discount rate
						3. Holding period
	-1	The Company utilizes valuation techniques consistent with the market, cost, and income approaches, or a combination thereof in determining fair value.
	The following methods and assumptions are used to estimate the fair value of the Company’s assets and liabilities that are accounted for at fair value.
	Investment securities – The Company utilizes independent third parties as its principal pricing sources for determining fair value of investment securities which are measured on a recurring basis. As a result, the Company receives estimates of fair values from at least two independent pricing sources for the majority of its individual securities within its investment portfolio. For investment securities traded in an active market, fair values are based on quoted market prices if available. If quoted market prices are not available, fair values are based on quoted market prices of comparable securities, broker quotes, comprehensive interest rate tables and pricing matrices or a combination thereof. For investment securities traded in a market that is not active, fair value is determined using unobservable inputs. All fair value estimates of the Company’s investment securities are reviewed and approved on a quarterly basis by its Investment Portfolio Manager and its Chief Financial Officer.
	The Company has determined that certain of its investment securities had a limited to non-existent trading market at March 31, 2015. As a result, the Company considers these investments as Level 3 in the fair value hierarchy. Specifically, the fair values of certain obligations of state and political subdivisions consisting primarily of certain unrated private placement bonds (the “private placement bonds”) in the amount of $19.1 million at March 31, 2015 were calculated using Level 3 hierarchy inputs and assumptions as the trading market for such securities was determined to be “not active.” This determination was based on the limited number of trades or, in certain cases, the existence of no reported trades for the private placement bonds. The private placement bonds are generally prepayable at par value at the option of the issuer. As a result, management believes the private placement bonds should be individually valued at the lower of (i) the matrix pricing provided by the Company’s third party pricing services for comparable unrated municipal securities or (ii) par value. At March 31, 2015, the third parties’ pricing matrices valued the Company’s portfolio of private placement bonds at $19.1 million which was equal to the aggregate par value of the private placement bonds. Accordingly, at March 31, 2015, the Company reported the private placement bonds at $19.1 million.
	Impaired non-purchased loans and leases – Fair values are measured on a nonrecurring basis and are based on the underlying collateral value of the impaired loan or lease, net of holding and selling costs, or the estimated discounted cash flows for such loan or lease. At March 31, 2015 the Company had reduced the carrying value of its impaired loans and leases (all of which are included in nonaccrual loans and leases) by $3.9 million to the estimated fair value of $12.6 million. The $3.9 million adjustment to reduce the carrying value of impaired loans and leases to estimated fair value consisted of $3.5 million of partial charge-offs and $0.4 million of specific loan and lease loss allocations.
	Impaired purchased loans – Impaired purchased loans are measured at fair value on a non-recurring basis. As of March 31, 2015, the Company had identified purchased loans where the expected performance had deteriorated from management’s performance expectations established in conjunction with the determination of the Day 1 Fair Values or where current information indicates it is probable that the Company will not be able to collect all amounts according to the contractual terms thereof (for purchased loans without evidence of credit deterioration at date of acquisition) or the expected performance of such loans had deteriorated from management’s performance expectations established in conjunction with the determination of the Day 1 Fair Values or since management’s most recent review of such portfolio’s performance (for purchased loans with evidence of credit deterioration at date of acquisition). As a result, the Company recorded partial charge-offs totaling $1.3 million during the first quarter of 2015. The Company also recorded provision for loan and lease losses of $1.3 million during the first quarter of 2015 to cover such charge-offs. In addition to these charge-offs, the Company transferred certain of these purchased loans to foreclosed assets. As a result of these actions, at March 31, 2015, the Company had $14.1 million of impaired purchased loans.
	Foreclosed assets – Repossessed personal properties and real estate acquired through or in lieu of foreclosure are measured on a non-recurring basis and are initially recorded at the lesser of current principal investment or fair value less estimated cost to sell (generally 8% to 10%) at the date of repossession or foreclosure. Purchased foreclosed assets are initially recorded at Day 1 Fair Values. In estimating such Day 1 Fair Values, management considered a number of factors including, among others, appraised value, estimated selling price, estimated holding periods and net present value (calculated using discount rates ranging from 8.0% to 9.5% per annum) of cash flows expected to be received. Valuations of these assets are periodically reviewed by management with the carrying value of such assets adjusted to the then estimated fair value net of estimated selling costs, if lower, until disposition. Fair values of foreclosed and repossessed assets are generally based on third party appraisals, broker price opinions or other valuations of the property.
	The following table presents additional information for the periods indicated about assets measured at fair value on a recurring basis and for which the Company has utilized Level 3 inputs to determine fair value.
			Investment
			Securities AFS
			(Dollars in thousands)
	Balance – January 1, 2015		$	19,401
Total realized gains (losses) included in earnings			0
Total unrealized gains (losses) included in comprehensive income			(87	)
Paydowns and maturities			(247	)
Sales			0
Transfers in and/or out of Level 3			0
Balance – March 31, 2015		$	19,067
Balance – January 1, 2014		$	18,682
Total realized gains (losses) included in earnings			0
Total unrealized gains (losses) included in comprehensive income			248
Paydowns and maturities			(383	)
Sales			0
Transfers in and/or out of Level 3			0
Balance – March 31, 2014		$	18,547

Fair_Value_of_Financial_Instru

Fair Value of Financial Instruments	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Financial Instruments	13	Fair Value of Financial Instruments
	The following methods and assumptions were used to estimate the fair value of financial instruments.
	Cash and due from banks – For these short-term instruments, the carrying amount is a reasonable estimate of fair value.
	Investment securities – The Company utilizes independent third parties as its principal pricing sources for determining fair value of investment securities which are measured on a recurring basis. As a result, the Company receives estimates of fair values from at least two independent pricing sources for the majority of its individual securities within its investment portfolio. For investment securities traded in an active market, fair values are based on quoted market prices if available. If quoted market prices are not available, fair values are based on quoted market prices of comparable securities, broker quotes, comprehensive interest rate tables, pricing matrices or a combination thereof. For investment securities traded in a market that is not active, fair value is determined using unobservable inputs. All fair value estimates of the Company’s investment securities are reviewed and approved on a quarterly basis by its Investment Portfolio Manager and its Chief Financial Officer. The Company’s investments in FHLB and FNBB equity securities totaling $10.4 million at March 31, 2015, $14.2 million at December 31, 2014 and $14.5 million at March 31, 2014, do not have readily determinable fair values and are carried at cost.
	Loans and leases – The fair value of loans and leases, including purchased loans, is estimated by discounting the contractual cash flows to be received in future periods using the current rate at which similar loans or leases would be made to borrowers or lessees with similar credit ratings and for the same remaining maturities.
	Deposit liabilities – The fair value of demand deposits, savings accounts, money market deposits and other transaction accounts is the amount payable on demand at the reporting date. The fair value of fixed maturity time deposits is estimated using the rate currently available for deposits of similar remaining maturities.
	Repurchase agreements – For these short-term instruments, the carrying amount is a reasonable estimate of fair value.
	Other borrowed funds – For these short-term instruments, the carrying amount is a reasonable estimate of fair value. The fair value of long-term instruments is estimated based on the current rates available to the Company for borrowings with similar terms and remaining maturities.
	Subordinated debentures – The fair values of these instruments are based primarily upon discounted cash flows using rates for securities with similar terms and remaining maturities.
	Off-balance sheet instruments – The fair values of commercial loan commitments and letters of credit are based on fees currently charged to enter into similar agreements, taking into account the remaining terms of the agreements, and were not material at March 31, 2015 and 2014 or at December 31, 2014.
	The fair values of certain of these instruments were calculated by discounting expected cash flows, which contain numerous uncertainties and involve significant judgments by management. Fair value is the estimated amount at which financial assets or liabilities could be exchanged in a current transaction between willing parties other than in a forced or liquidation sale. Because no market exists for certain of these financial instruments and because management does not intend to sell these financial instruments, the Company did not know whether the fair values represent values at which the respective financial instruments could be sold individually or in the aggregate.
	The following table presents the carrying amounts and estimated fair values for the dates indicated and the fair value hierarchy of the Company’s financial instruments.
				March 31,
				2015				2014				December 31, 2014
			Fair	Carrying		Estimated		Carrying		Estimated		Carrying		Estimated
			Value	Amount		Fair		Amount		Fair		Amount		Fair
			Hierarchy			Value				Value				Value
				(Dollars in thousands)
	Financial assets:
	Cash and cash equivalents		Level 1	$	425,794	$	425,794	$	188,351	$	188,351	$	150,203	$	150,203
	Investment securities AFS		Levels 1, 2 and 3		784,725		784,725		687,661		687,661		839,321		839,321
	Loans and leases, net of ALLL		Level 3		6,299,122		6,230,658		3,528,130		3,496,946		5,074,899		5,042,831
	FDIC loss share receivable		Level 3		0		0		57,782		57,722		0		0
	Financial liabilities:
	Demand, savings and interest bearing transaction deposits		Level 1	$	4,563,972	$	4,563,972	$	3,085,886	$	3,085,886	$	4,038,443	$	4,038,443
	Time deposits		Level 2		2,152,689		2,158,211		830,318		830,583		1,457,939		1,463,590
	Repurchase agreements with customers		Level 1		76,960		76,960		51,140		51,140		65,578		65,578
	Other borrowings		Level 2		161,318		172,180		280,885		317,186		190,855		203,493
	FDIC clawback payable		Level 3		0		0		26,202		26,202		0		0
	Subordinated debentures		Level 2		117,264		71,442		64,950		32,767		64,950		39,103

Changes_In_and_Reclassificatio

Changes In and Reclassifications From Accumulated Other Comprehensive Income ("AOCI")	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Changes In and Reclassifications From Accumulated Other Comprehensive Income ("AOCI")	14	Changes In and Reclassifications From Accumulated Other Comprehensive Income (“AOCI”)
	The following table presents changes in AOCI for the periods indicated.
			Three Months Ended
			March 31,
			2015			2014
			(Dollars in thousands)
	Beginning balance of AOCI – unrealized gains and losses on investment securities AFS		$	14,132		$	(3,672	)
	Other comprehensive income (loss):
	Unrealized gains and losses on investment securities AFS			2,914			11,330
	Tax effect of unrealized gains and losses on investment securities AFS			(1,110	)		(4,444	)
	Amounts reclassified from AOCI			(2,534	)		(5	)
	Tax effect of amounts reclassified from AOCI			965			2
	Total other comprehensive income (loss)			235			6,883
	Ending balance of AOCI – unrealized gains and losses on investment securities AFS		$	14,367		$	3,211
	Amounts reclassified from AOCI are included in net gains on investment securities and the tax effect of amounts reclassified from AOCI are included in provision for income tax in the consolidated statements of income. The amounts reclassified from AOCI relate entirely to unrealized gains/losses on investment securities AFS.

Other_Operating_Expenses

Other Operating Expenses	3 Months Ended
	Mar. 31, 2015
Other Income and Expenses [Abstract]
Other Operating Expenses	15	Other Operating Expenses
	The following table is a summary of other operating expenses for the periods indicated.
			Three Months Ended
			March 31,
			2015		2014
			(Dollars in thousands)
	Salaries and employee benefits		$	22,597	$	17,689
	Net occupancy and equipment			7,291		5,044
	Other operating expenses:
	Postage and supplies			915		770
	Advertising and public relations			583		400
	Telecommunication services			1,348		1,001
	Professional and outside services			4,386		2,128
	Software and data processing			749		6,024
	Travel and meals			796		556
	FDIC insurance			750		503
	FDIC and state assessments			310		260
	ATM expense			708		210
	Loan collection and repossession expense			1,733		460
	Writedowns of foreclosed and other assets			2,192		64
	Amortization of intangibles			1,596		813
	FHLB prepayment penalty			2,480		0
	Other			1,750		1,532
	Total non-interest expense		$	50,184	$	37,454

Recent_Accounting_Pronouncemen

Recent Accounting Pronouncements	3 Months Ended
	Mar. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	16	Recent Accounting Pronouncements
	In May 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09 “Revenue from Contracts with Customers.” ASU 2014-09 provides guidance that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. ASU 2014-09 is effective for annual and interim periods beginning after December 15, 2016, although the FASB recently proposed deferring its effective date by one year. The Company is currently evaluating the impact, if any, ASU 2014-09 will have on its financial position, results of operations, and its financial statement disclosures.
	In January 2015, the FASB issued ASU 2015-01, “Income Statement – Extraordinary and Unusual Items (Subtopic 225-20) – Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary Items.” ASU 2015-01 eliminates from GAAP the concept of extraordinary items, which, among other things, required an entity to segregate extraordinary items considered to be unusual and infrequent from the results of ordinary operations and show the item separately in the income statement, net of tax, after income from continuing operations. ASU 2015-01 is effective for interim and annual periods beginning after December 15, 2015. ASU 2015-01 is not expected to have a significant impact on the Company’s financial position, results of operations and its financial statement disclosures.
	In February 2015, FASB issued ASU 2015-02 “Consolidation (Topic 810): Amendments to the Consolidation Analysis” which amends the consolidation requirements of ASU 810 by changing the consolidation analysis required under GAAP. The revised guidance amends the consolidation analysis based on certain fee arrangements or relationships to the reporting entity and, for limited partnerships, requires entities to consider the limited partner’s rights relative to the general partner. ASU 2015-02 is effective for annual and interim periods beginning after December 15, 2015. The Company is currently evaluating the impact, if any, ASU 2015-02 will have on its financial position, results of operations, and its financial statement disclosures.
	In April 2015, the FASB issued ASU 2015-03, “Interest – Imputation of Interest (Subtopic 835-30) – Simplifying the Presentation of Debt Issuance Costs.” ASU 2015-03 requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The recognition and measurement guidance for debt issuance costs are not affected by the amendments in ASU 2015-03. ASU 2015-03 is effective for interim and annual periods beginning after December 1, 2015. ASU 2015-03 is not expected to have a significant impact on the Company’s financial position, results of operations and its financial statement disclosures.

Subsequent_Events

Subsequent Events	3 Months Ended
	Mar. 31, 2015
Subsequent Events [Abstract]
Subsequent Events	17	Subsequent Event
	On May 6, 2015, the Company entered into a definitive agreement and plan of merger and reorganization (the “BCAR Agreement”) with Bank of the Carolinas Corporation (“BCAR”) and its wholly-owned bank subsidiary Bank of the Carolinas, headquartered in Mocksville, North Carolina, whereby the Company will acquire all of the outstanding common stock of BCAR in a transaction valued at approximately $64.7 million. Bank of the Carolinas operates eight full service banking offices in North Carolina. At March 31, 2015, BCAR reported approximately $363 million in total assets, approximately $279 million in total loans and approximately $314 million in total deposits.
	Under the terms of the BCAR Agreement, each outstanding share of common stock of BCAR will be converted into the right to receive shares of the Company’s common stock, plus cash in lieu of any fractional share, all subject to certain conditions and potential adjustments. The number of Company shares to be issued will be determined based on the Company’s 10-day average closing stock price as of the second business day prior to the closing date, subject to a minimum price of $29.28 per share and a maximum price of $48.80 per share. Upon the closing of the transaction, which is expected to occur in the third quarter of 2015, BCAR will merge into the Company and Bank of the Carolinas will merge into the Bank. Completion of the transaction is subject to certain closing conditions, including receipt of customary regulatory approvals and the approval of BCAR shareholders.

Acquisitions_Tables

Acquisitions (Tables)	3 Months Ended
	Mar. 31, 2015
Business Combinations [Abstract]
Summary of Assets Acquired and Liabilities Assumed in Acquisition	The following table provides a summary of the assets acquired and liabilities assumed as recorded by Intervest, the preliminary estimates of the fair value adjustments necessary to adjust those acquired assets and assumed liabilities to estimated fair value, and the preliminary estimates of the resultant fair values of those assets and liabilities as recorded by the Company. As provided for under GAAP, management has up to 12 months following the date of acquisition to finalize the fair values of the acquired assets and assumed liabilities. Once management has finalized the fair values of acquired assets and assumed liabilities within this 12-month period, management considers such values to be the day 1 fair values (“Day 1 Fair Values”). The preliminary fair value adjustments and the preliminary resultant fair values shown in the following table continue to be evaluated by management and may be subject to further adjustment.
			February 10, 2015
			As Recorded			Preliminary				As Recorded
			by			Fair Value				by the
			Intervest			Adjustments(1)				Company(1)
			(Dollars in thousands)
	Assets acquired:
	Cash, due from banks and interest earning deposits		$	274,343		$	0			$	274,343
	Investment securities			21,495			321		a		21,816
	Loans			1,108,439			(33,868	)	b		1,074,571
	Allowance for loan losses			(25,208	)		25,208		b		0
	Premises and equipment			4,357			2,256		c		6,613
	Foreclosed assets			2,350			(1,710	)	d		640
	Accrued interest receivable and other assets			34,076			(4,091	)	e		29,985
	Core deposit intangible asset			0			4,595		f		4,595
	Deferred income taxes			11,758			8,082		g		19,840
	Total assets acquired			1,431,610			793				1,432,403
	Liabilities assumed:
	Deposits			1,162,437			22,211		h		1,184,648
	Subordinated debentures			56,702			(4,463	)	i		52,239
	Accrued interest payable and other liabilities			3,608			358		j		3,966
	Total liabilities assumed			1,222,747			18,106				1,240,853
	Net assets acquired		$	208,863		$	(17,313	)			191,550
	Consideration paid:
	Cash in lieu of fractional shares										(7	)
	Stock										(238,476	)
	Total consideration paid										(238,483	)
	Goodwill									$	46,933
	(1)	The acquisition of Intervest closed on February 10, 2015. Accordingly, each of the fair value adjustments shown are preliminary estimates of the purchase accounting adjustments. Management is continuing to evaluate each of these fair value adjustments and may revise one or more of such fair value adjustments in future periods based on this continuing evaluation. To the extent that any of these preliminary fair value adjustments are revised in future periods, the resultant fair values and the amount of goodwill could change.
	Explanation of preliminary fair value adjustments
	a-		Adjustment reflects the fair value adjustment based on the pricing of the acquired investment securities portfolio.
	b-		Adjustment reflects the fair value adjustment based on the evaluation of the acquired loan portfolio and to eliminate the recorded allowance for loan losses.
	c-		Adjustment reflects the fair value adjustment based on the evaluation of the premises and equipment acquired.
	d-		Adjustment reflects the fair value adjustment based on the evaluation of the acquired foreclosed assets.
	e-		Adjustment reflects the fair value adjustment based on the evaluation of accrued interest receivable and other assets.
	f-		Adjustment reflects the fair value adjustment for the core deposit intangible asset recorded as a result of the acquisition.
	g-		This adjustment reflects the differences in the carrying values of acquired assets and assumed liabilities for financial reporting purposes and their basis for federal income tax purposes.
	h-		Adjustment reflects the fair value adjustment based on the evaluation of the acquired deposits.
	i-		Adjustment reflects the fair value adjustment of these assumed liabilities based on a valuation of such instruments by an independent, third party valuation firm.
	j-		Adjustment reflects the amount needed to adjust other liabilities to estimated fair value and to record certain liabilities directly attributable to the Intervest acquisition.
Summary of Supplemental Pro-forma Information	The following unaudited supplemental pro forma information is presented to show the estimated results assuming Intervest was acquired as of the beginning of the earliest period presented, adjusted for estimated potential costs savings. These unaudited pro forma results are not necessarily indicative of the operating results that the Company would have achieved had it completed the acquisition as of January 1, 2014 and should not be considered as representative of future operating results.
			Three Months Ended
			March 31,
			2015			2014
			(Dollars in thousands,
			except per share amounts)
	Net interest income – pro forma (unaudited)		$	90,345		$	67,947
	Net income – pro forma (unaudited)		$	43,924		$	30,504
	Diluted earnings per common share – pro forma (unaudited)		$	0.5		$	0.38

Earnings_Per_Common_Share_EPS_

Earnings Per Common Share ("EPS") (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Schedule of Calculation of Numerator and Denominator in Basic and Diluted Earnings Per Share	The following table presents the computation of basic and diluted EPS for the periods indicated.
		Three Months Ended
		March 31,
		2015		2014
		(In thousands, except per
		share amounts)
	Numerator:
	Distributed earnings allocated to common stock	$	10,413	$	8,108
	Undistributed earnings allocated to common stock		29,481		17,168
	Net income available to common stock	$	39,894	$	25,276
	Denominator:
	Denominator for basic EPS – weighted-average common shares		83,699		73,802
	Effect of dilutive securities – stock options		710		692
	Denominator for diluted EPS – weighted-average common shares and assumed conversions		84,409		74,494
	Basic EPS	$	0.48	$	0.34
	Diluted EPS	$	0.47	$	0.34

Investment_Securities_Tables

Investment Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Summary of Amortized Cost and Estimated Fair Value of Investment Securities AFS	The following table presents the amortized cost and estimated fair value of investment securities AFS as of the dates indicated. The Company’s investment in the “CRA qualified investment fund” includes shares held in a mutual fund that qualifies under the Community Reinvestment Act of 1977 for community reinvestment purposes. The Company’s holdings of equity securities in Federal Home Loan Bank of Dallas (“FHLB”) and First National Banker’s Bankshares, Inc. (“FNBB”) do not have readily determinable fair values and are carried at cost.
		Amortized			Gross		Gross			Estimated
		Cost			Unrealized		Unrealized			Fair Value
					Gains		Losses
		(Dollars in thousands)
	March 31, 2015:
	Obligations of state and political subdivisions	$	496,251		$	16,203	$	(247	)	$	512,207
	U.S. Government agency securities		252,728			7,503		(256	)		259,975
	Corporate obligations		622			0		0			622
	CRA qualified investment fund		1,022			6		0			1,028
	FHLB and FNBB equity securities		10,443			0		0			10,443
	Total	$	761,066		$	23,712	$	(503	)	$	784,275
	December 31, 2014:
	Obligations of state and political subdivisions	$	555,335		$	18,267	$	(393	)	$	573,209
	U.S. Government agency securities		245,854			6,144		(765	)		251,233
	Corporate obligations		654			0		0			654
	FHLB and FNBB equity securities		14,225			0		0			14,225
	Total	$	816,068		$	24,411	$	(1,158	)	$	839,321
	March 31, 2014:
	Obligations of state and political subdivisions	$	447,368		$	10,010	$	(4,630	)	$	452,748
	U.S. Government agency securities		219,836			3,526		(3,622	)		219,740
	Corporate obligations		686			0		0			686
	FHLB and FNBB equity securities		14,487			0		0			14,487
	Total	$	682,377		$	13,536	$	(8,252	)	$	687,661
Gross Unrealized Losses and Estimated Fair Value of Investment Securities	The following table shows estimated fair value of investment securities AFS having gross unrealized losses and the amount of such unrealized losses, aggregated by investment category and length of time that individual investment securities have been in a continuous unrealized loss position, as of the dates indicated.
		Less than 12 Months					12 Months or More					Total
		Estimated			Unrealized		Estimated			Unrealized		Estimated		Unrealized
		Fair Value			Losses		Fair Value			Losses		Fair Value		Losses
		(Dollars in thousands)
	March 31, 2015:
	Obligations of state and political subdivisions	$	39,112		$	189	$	3,437		$	58	$	42,549	$	247
	U.S. Government agency securities		23,451			171		7,241			85		30,692		256
	Total temporarily impaired securities	$	62,563		$	360	$	10,678		$	143	$	73,241	$	503
	December 31, 2014:
	Obligations of state and political subdivisions	$	29,174		$	75	$	34,414		$	318	$	63,588	$	393
	U.S. Government agency securities		9,630			25		47,626			740		57,256		765
	Total temporarily impaired securities	$	38,804		$	100	$	82,040		$	1,058	$	120,844	$	1,158
	March 31, 2014:
	Obligations of state and political subdivisions	$	51,961		$	2,048	$	47,890		$	2,582	$	99,851	$	4,630
	U.S. Government agency securities		69,783			3,582		1,038			40		70,821		3,622
	Total temporarily impaired securities	$	121,744		$	5,630	$	48,928		$	2,622	$	170,672	$	8,252
Maturity Distribution of Investment Securities AFS	The following table shows the amortized cost and estimated fair value of investment securities AFS by maturity or estimated date of repayment as of the date indicated.
		March 31, 2015
	Maturity or Estimated Repayment	Amortized			Estimated
		Cost			Fair Value
		(Dollars in thousands)
	One year or less	$	37,328		$	38,391
	After one year to five years		139,542			142,725
	After five years to ten years		187,370			192,169
	After ten years		396,826			410,990
	Total	$	761,066		$	784,275
Sales Activities of Company's Investment Securities AFS are Summarized	The following table is a summary of sales activities in the Company’s investment securities AFS for the periods indicated.
		Three Months Ended
		March 31,
		2015			2014
		(Dollars in thousands)
	Sales proceeds	$	30,117		$	1,224
	Gross realized gains	$	2,535		$	5
	Gross realized losses		(1	)		0
	Net gains on investment securities	$	2,534		$	5

Allowance_for_Loan_and_Lease_L1

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators (Tables)	3 Months Ended
	Mar. 31, 2015
Text Block [Abstract]
Schedule of Activity Within Allowance for Loan and Lease Losses	The following table is a summary of activity within the ALLL for the periods indicated.
			Three Months Ended
			March 31,
			2015			2014
			(Dollars in thousands)
	Beginning balance		$	52,918		$	42,945
	Non-purchased loans and leases charged off			(4,079	)		(920	)
	Recoveries of non-purchased loans and leases previously charged off			308			736
	Net non-purchased loans and leases charged off			(3,771	)		(184	)
	Purchased loans charged off, net			(1,315	)		(204	)
	Net charge-offs – total loans and leases			(5,086	)		(388	)
	Provision for loan and lease losses:
	Non-purchased loans and leases			5,000			1,100
	Purchased loans			1,315			204
	Total provision			6,315			1,304
	Ending balance		$	54,147		$	43,861
Summary of Company's Allowance for Loan and Lease Losses	The following table is a summary of the Company’s ALLL for the periods indicated.
			Beginning			Charge-offs			Recoveries		Provision			Ending
			Balance											Balance
			(Dollars in thousands)
	Three months ended March 31, 2015:
	Real estate:
	Residential 1-4 family		$	5,482		$	(529	)	$	11	$	693		$	5,657
	Non-farm/non-residential			17,190			(205	)		12		769			17,766
	Construction/land development			15,960			(302	)		37		1,885			17,580
	Agricultural			2,558			(13	)		0		(19	)		2,526
	Multifamily residential			2,147			0			0		276			2,423
	Commercial and industrial			4,873			(2,447	)		16		859			3,301
	Consumer			818			(45	)		21		30			824
	Direct financing leases			2,989			(186	)		6		449			3,258
	Other			901			(352	)		205		58			812
	Purchased loans			0			(1,315	)		0		1,315			0
	Total		$	52,918		$	(5,394	)	$	308	$	6,315		$	54,147
	Year ended December 31, 2014:
	Real estate:
	Residential 1-4 family		$	4,701		$	(577	)	$	135	$	1,223		$	5,482
	Non-farm/non-residential			13,633			(1,357	)		33		4,881			17,190
	Construction/land development			12,306			(638	)		11		4,281			15,960
	Agricultural			3,000			(214	)		14		(242	)		2,558
	Multifamily residential			2,504			0			0		(357	)		2,147
	Commercial and industrial			2,855			(720	)		808		1,930			4,873
	Consumer			917			(222	)		80		43			818
	Direct financing leases			2,266			(602	)		49		1,276			2,989
	Other			763			(793	)		266		665			901
	Purchased loans			0			(3,215	)		0		3,215			0
	Total		$	42,945		$	(8,338	)	$	1,396	$	16,915		$	52,918
	Three months ended March 31, 2014:
	Real estate:
	Residential 1-4 family		$	4,701		$	(199	)	$	22	$	98		$	4,622
	Non-farm/non-residential			13,633			(73	)		3		450			14,013
	Construction/land development			12,306			0			8		514			12,828
	Agricultural			3,000			(15	)		5		28			3,018
	Multifamily residential			2,504			0			0		(75	)		2,429
	Commercial and industrial			2,855			(374	)		628		(371	)		2,738
	Consumer			917			(41	)		18		(63	)		831
	Direct financing leases			2,266			(146	)		6		312			2,438
	Other			763			(72	)		46		207			944
	Purchased loans			0			(204	)		0		204			0
	Total		$	42,945		$	(1,124	)	$	736	$	1,304		$	43,861
Summary of Allowance for Loan and Lease Losses and Recorded Investment in Non-Purchased Loans and Leases	The following table is a summary of the Company’s ALLL and recorded investment in non-purchased loans and leases of the dates indicated.
			ALLL								Non-Purchased Loans and Leases
			ALLL for			ALLL for			Total		Individually			All Other		Total Loans
			Individually			All Other			ALLL		Evaluated			Loans and		and Leases
			Evaluated			Loans and					Impaired			Leases
			Impaired			Leases					Loans and
			Loans and								Leases
			Leases
			(Dollars in thousands)
	March 31, 2015:
	Real estate:
	Residential 1-4 family		$	295		$	5,362		$	5,657	$	2,509		$	301,326	$	303,835
	Non-farm/non-residential			10			17,756			17,766		538			1,574,413		1,574,951
	Construction/land development			2			17,578			17,580		9,413			1,650,924		1,660,337
	Agricultural			0			2,526			2,526		305			48,879		49,184
	Multifamily residential			0			2,423			2,423		0			228,973		228,973
	Commercial and industrial			53			3,248			3,301		131			252,947		253,078
	Consumer			3			821			824		33			24,836		24,869
	Direct financing leases			0			3,258			3,258		0			126,326		126,326
	Other			0			812			812		9			89,543		89,552
	Total		$	363		$	53,784		$	54,147	$	12,938		$	4,298,167	$	4,311,105
	December 31, 2014:
	Real estate:
	Residential 1-4 family		$	356		$	5,126		$	5,482	$	2,734		$	280,519	$	283,253
	Non-farm/non-residential			18			17,172			17,190		2,507			1,501,034		1,503,541
	Construction/land development			68			15,892			15,960		14,304			1,397,534		1,411,838
	Agricultural			6			2,552			2,558		365			46,870		47,235
	Multifamily residential			0			2,147			2,147		0			211,156		211,156
	Commercial and industrial			644			4,229			4,873		623			287,084		287,707
	Consumer			3			815			818		34			25,635		25,669
	Direct financing leases			0			2,989			2,989		0			115,475		115,475
	Other			0			901			901		8			93,988		93,996
	Total		$	1,095		$	51,823		$	52,918	$	20,575		$	3,959,295	$	3,979,870
	March 31, 2014:
	Real estate:
	Residential 1-4 family		$	385		$	4,237		$	4,622	$	3,811		$	248,977	$	252,788
	Non-farm/non-residential			29			13,984			14,013		1,627			1,142,856		1,144,483
	Construction/land development			2			12,826			12,828		325			795,801		796,126
	Agricultural			243			2,775			3,018		817			43,091		43,908
	Multifamily residential			0			2,429			2,429		0			195,332		195,332
	Commercial and industrial			624			2,114			2,738		626			137,038		137,664
	Consumer			3			828			831		48			23,721		23,769
	Direct financing leases			0			2,438			2,438		0			92,856		92,856
	Other			0			944			944		10			91,567		91,577
	Total		$	1,286		$	42,575		$	43,861	$	7,264		$	2,771,239	$	2,778,503
Schedule of Impaired Non-purchased Loans and Leases, FDIC Loss Share Agreements	The following table is a summary of impaired non-purchased loans and leases as of and for the three months ended March 31, 2015.
			Principal			Net			Principal		Specific			Weighted
			Balance			Charge-offs			Balance,		ALLL			Average
						to Date			Net of					Carrying
									Charge-offs					Value – Three
														Months Ended
														March 31,
														2015
			(Dollars in thousands)
	Impaired loans and leases for which there is a related ALLL:
	Real estate:
	Residential 1-4 family		$	3,123		$	(1,814	)	$	1,309	$	295		$	1,399
	Non-farm/non-residential			184			(142	)		42		10			292
	Construction/land development			38			(22	)		16		2			2,064
	Agricultural			0			0			0		0			46
	Commercial and industrial			632			(631	)		1		53			0
	Consumer			40			(23	)		17		3			271
	Other			0			0			0		0			18
	Total impaired loans and leases with a related ALLL			4,017			(2,632	)		1,385		363			4,090
	Impaired loans and leases for which there is not a related ALLL:
	Real estate:
	Residential 1-4 family			1,379			(179	)		1,200		0			1,223
	Non-farm/non-residential			633			(137	)		496		0			1,231
	Construction/land development			9,500			(102	)		9,398		0			9,796
	Agricultural			507			(202	)		305		0			288
	Multifamily residential			133			(133	)		0		0			0
	Commercial and industrial			290			(159	)		131		0			106
	Consumer			20			(5	)		15		0			15
	Other			8			0			8		0			8
	Total impaired loans and leases without a related ALLL			12,470			(917	)		11,553		0			12,667
	Total impaired loans and leases		$	16,487		$	(3,549	)	$	12,938	$	363		$	16,757
	The following table is a summary of impaired non-purchased loans and leases as of and for the year ended December 31, 2014.
			Principal			Net			Principal		Specific			Weighted
			Balance			Charge-offs			Balance,		ALLL			Average
						to Date			Net of					Carrying
									Charge-offs					Value – Year
														Ended
														December 31,
														2014
			(Dollars in thousands)
	Impaired loans and leases for which there is a related ALLL:
	Real estate:
	Residential 1-4 family		$	3,163		$	(1,674	)	$	1,489	$	356		$	1,457
	Non-farm/non-residential			762			(220	)		542		18			211
	Construction/land development			4,656			(545	)		4,111		68			1,040
	Agricultural			105			(12	)		93		6			217
	Commercial and industrial			1,233			(691	)		542		644			554
	Consumer			41			(23	)		18		3			20
	Total impaired loans and leases with a related ALLL			9,960			(3,165	)		6,795		1,095			3,499
	Impaired loans and leases for which there is not a related ALLL:
	Real estate:
	Residential 1-4 family			1,373			(128	)		1,245		0			1,581
	Non-farm/non-residential			2,676			(711	)		1,965		0			1,988
	Construction/land development			10,378			(185	)		10,193		0			7,600
	Agricultural			474			(202	)		272		0			383
	Multifamily residential			133			(133	)		0		0			123
	Commercial and industrial			264			(183	)		81		0			75
	Consumer			81			(65	)		16		0			18
	Other			8			0			8		0			8
	Total impaired loans and leases without a related ALLL			15,387			(1,607	)		13,780		0			11,776
	Total impaired loans and leases		$	25,347		$	(4,772	)	$	20,575	$	1,095		$	15,275
	The following table is a summary of impaired non-purchased loans and leases as of and for the three months ended March 31, 2014.
			Principal			Net			Principal		Specific			Weighted
			Balance			Charge-offs			Balance,		ALLL			Average
			to Date			Net of					Carrying
						Charge-offs					Value – Three
											Months Ended
											March 31,
											2014
		(Dollars in thousands)
Impaired loans and leases for which there is a related ALLL:
Real estate:
Residential 1-4 family		$	3,164		$	(1,726	)	$	1,438	$	385		$	1,677
Non-farm/non-residential			188			(127	)		61		29			53
Construction/land development			38			(22	)		16		2			16
Agricultural			360			(12	)		348		243			409
Commercial and industrial			1,368			(803	)		565		624			588
Consumer			103			(80	)		23		3			23
Other			0			0			0		0			8
Total impaired loans and leases with a related ALLL			5,221			(2,770	)		2,451		1,286			2,774
Impaired loans and leases for which there is not a related ALLL:
Real estate:
Residential 1-4 family			2,845			(472	)		2,373		0			2,252
Non-farm/non-residential			2,702			(1,136	)		1,566		0			1,840
Construction/land development			390			(81	)		309		0			264
Agricultural			513			(44	)		469		0			441
Multifamily residential			133			(133	)		0		0			0
Commercial and industrial			220			(159	)		61		0			68
Consumer			34			(9	)		25		0			26
Other			30			(20	)		10		0			10
Total impaired loans and leases without a related ALLL			6,867			(2,054	)		4,813		0			4,901
Total impaired loans and leases		$	12,088		$	(4,824	)	$	7,264	$	1,286		$	7,675
Summary of Credit Quality Indicators for Loans and Leases, Including Purchased and Non-Purchased Loans and Leases	The following table is a summary of credit quality indicators for the Company’s non-purchased loans and leases as of the dates indicated.
			Satisfactory			Moderate			Watch		Substandard			Total
			(Dollars in thousands)
	March 31, 2015:
	Real estate:
	Residential 1-4 family (1)		$	293,140		$	0		$	4,456	$	6,239		$	303,835
	Non-farm/non-residential			1,356,456			158,588			53,874		6,033			1,574,951
	Construction/land development			1,433,497			203,405			11,049		12,386			1,660,337
	Agricultural			23,663			13,974			9,293		2,254			49,184
	Multifamily residential			187,966			37,686			1,663		1,658			228,973
	Commercial and industrial			180,448			68,809			2,403		1,418			253,078
	Consumer (1)			24,243			0			369		257			24,869
	Direct financing leases			125,845			354			75		52			126,326
	Other (1)			84,596			4,716			221		19			89,552
	Total		$	3,709,854		$	487,532		$	83,403	$	30,316		$	4,311,105
	December 31, 2014:
	Real estate:
	Residential 1-4 family (1)		$	271,576		$	0		$	4,082	$	7,595		$	283,253
	Non-farm/non-residential			1,300,582			142,688			53,863		6,408			1,503,541
	Construction/land development			1,190,005			192,046			11,135		18,652			1,411,838
	Agricultural			22,446			12,375			10,226		2,188			47,235
	Multifamily residential			171,806			37,886			713		751			211,156
	Commercial and industrial			208,054			59,967			18,310		1,376			287,707
	Consumer (1)			25,267			0			141		261			25,669
	Direct financing leases			114,586			715			117		57			115,475
	Other (1)			89,364			4,312			286		34			93,996
	Total		$	3,393,686		$	449,989		$	98,873	$	37,322		$	3,979,870
	March 31, 2014:
	Real estate:
	Residential 1-4 family (1)		$	244,259		$	0		$	2,449	$	6,080		$	252,788
	Non-farm/non-residential			954,057			130,787			53,658		5,981			1,144,483
	Construction/land development			613,474			155,254			23,254		4,144			796,126
	Agricultural			21,228			9,914			9,747		3,019			43,908
	Multifamily residential			164,062			29,625			389		1,256			195,332
	Commercial and industrial			103,039			31,434			1,642		1,549			137,664
	Consumer (1)			23,203			0			220		346			23,769
	Direct financing leases			91,927			881			0		48			92,856
	Other (1)			89,181			2,253			113		30			91,577
	Total		$	2,304,430		$	360,148		$	91,472	$	22,453		$	2,778,503
	-1	The Company does not risk rate its residential 1-4 family loans, its consumer loans, and certain “other” loans. However, for purposes of the above table, the Company considers such loans to be (i) satisfactory – if they are performing and less than 30 days past due, (ii) watch – if they are performing and 30 to 89 days past due or (iii) substandard – if they are nonperforming or 90 days or more past due.
	The following table is a summary of credit quality indicators for the Company’s purchased loans as of the dates indicated.
			Purchased Loans Without Evidence													Purchased Loans				Total
			of Credit Deterioration at Acquisition													With Evidence of				Purchased
																Credit Deterioration				Loans
																at Acquisition
			FV 33			FV 44			FV 55		FV 36			FV 77		FV 66		FV 88
			(Dollars in thousands)
	March 31, 2015:
	Real estate:
	Residential 1-4 family		$	67,490		$	107,772		$	33,991	$	64,957		$	158	$	92,829	$	2,329	$	369,526
	Non-farm/non-residential			227,184			759,926			135,766		4,353			256		151,342		7,000		1,285,827
	Construction/land development			11,613			20,647			7,160		8,553			725		27,072		3,015		78,785
	Agricultural			8,815			19,105			1,937		1,025			108		6,716		0		37,706
	Multifamily residential			23,781			122,937			29,243		3,523			65		11,930		0		191,479
	Total real estate			338,883			1,030,387			208,097		82,411			1,312		289,889		12,344		1,963,323
	Commercial and industrial			15,608			20,960			4,539		7,042			23		8,059		462		56,693
	Consumer			1,033			316			322		9,959			2		329		4		11,965
	Other			4,623			3,689			310		763			0		798		0		10,183
	Total		$	360,147		$	1,055,352		$	213,268	$	100,175		$	1,337	$	299,075	$	12,810	$	2,042,164
	December 31, 2014:
	Real estate:
	Residential 1-4 family		$	73,196		$	81,840		$	30,180	$	71,687		$	151	$	96,752	$	1,899	$	355,705
	Non-farm/non-residential			166,754			180,522			32,157		4,906			505		114,217		5,828		504,889
	Construction/land development			21,803			26,858			4,312		13,708			0		28,497		4,598		99,776
Agricultural			10,444			25,187			2,409		1,525			0		8,331		92		47,988
Multifamily residential			22,731			11,646			1,971		884			67		4,823		312		42,434
Total real estate			294,928			326,053			71,029		92,710			723		252,620		12,729		1,050,792
Commercial and industrial			20,340			23,048			4,900		10,659			22		9,297		559		68,825
Consumer			1,605			272			420		12,538			3		426		4		15,268
Other			4,845			5,830			597		945			0		845		0		13,062
Total		$	321,718		$	355,203		$	76,946	$	116,852		$	748	$	263,188	$	13,292	$	1,147,947
March 31, 2014:
Real estate:
Residential 1-4 family		$	27,899		$	37,442		$	21,933	$	34,004		$	0	$	115,707	$	3,621	$	240,606
Non-farm/non-residential			59,720			102,836			32,160		2,701			0		140,933		14,534		352,884
Construction/land development			9,880			18,384			10,605		4,550			0		40,075		10,394		93,888
Agricultural			1,260			7,490			842		146			0		11,050		339		21,127
Multifamily residential			3,216			5,903			5,002		1,046			0		10,799		310		26,276
Total real estate			101,975			172,055			70,542		42,447			0		318,564		29,198		734,781
Commercial and industrial			10,766			14,526			5,138		2,648			0		12,975		130		46,183
Consumer			1,448			204			332		4,065			0		647		4		6,700
Other			1,204			2,835			529		200			0		1,056		0		5,824
Total		$	115,393		$	189,620		$	76,541	$	49,360		$	0	$	333,242	$	29,332	$	793,488
Schedule of Aging Analysis Past Due Loans and Leases, Loans Purchased and Non-Purchased by FDIC Loss Share Agreements	The following table is an aging analysis of past due non-purchased loans and leases as of the dates indicated.
			30-89 Days			90 Days			Total		Current (3)			Total
			Past Due (1)			or More (2)			Past Due
			(Dollars in thousands)
	March 31, 2015:
	Real estate:
	Residential 1-4 family		$	5,161		$	1,618		$	6,779	$	297,056		$	303,835
	Non-farm/non-residential			4,276			376			4,652		1,570,299			1,574,951
	Construction/land development			229			9,414			9,643		1,650,694			1,660,337
	Agricultural			1,685			305			1,990		47,194			49,184
	Multifamily residential			0			0			0		228,973			228,973
	Commercial and industrial			1,862			198			2,060		251,018			253,078
	Consumer			394			27			421		24,448			24,869
	Direct financing leases			41			52			93		126,233			126,326
	Other			163			8			171		89,381			89,552
	Total		$	13,811		$	11,998		$	25,809	$	4,285,296		$	4,311,105
	December 31, 2014:
	Real estate:
	Residential 1-4 family		$	6,352		$	1,536		$	7,888	$	275,365		$	283,253
	Non-farm/non-residential			2,708			1,445			4,153		1,499,388			1,503,541
	Construction/land development			3,520			12,881			16,401		1,395,437			1,411,838
	Agricultural			1,680			304			1,984		45,251			47,235
	Multifamily residential			0			0			0		211,156			211,156
	Commercial and industrial			586			94			680		287,027			287,707
	Consumer			161			55			216		25,453			25,669
	Direct financing leases			39			54			93		115,382			115,475
	Other			58			12			70		93,926			93,996
	Total		$	15,104		$	16,381		$	31,485	$	3,948,385		$	3,979,870
	March 31, 2014:
	Real estate:
	Residential 1-4 family		$	3,167		$	2,108		$	5,275	$	247,513		$	252,788
	Non-farm/non-residential			647			1,376			2,023		1,142,460			1,144,483
	Construction/land development			7,077			3,950			11,027		785,099			796,126
	Agricultural			495			582			1,077		42,831			43,908
	Multifamily residential			0			0			0		195,332			195,332
	Commercial and industrial			891			16			907		136,757			137,664
	Consumer			240			78			318		23,451			23,769
	Direct financing leases			59			0			59		92,797			92,856
	Other			17			9			26		91,551			91,577
	Total		$	12,593		$	8,119		$	20,712	$	2,757,791		$	2,778,503
	-1	Includes $0.6 million, $0.9 million and $0.6 million at March 31, 2015, December 31, 2014 and March 31, 2014, respectively, of loans and leases on nonaccrual status.
	-2	All loans and leases greater than 90 days past due were on nonaccrual status at March 31, 2015 and 2014 and December 31, 2014.
	-3	Includes $1.7 million, $0.4 million and $3.0 million of loans and leases on nonaccrual status at March 31, 2015, December 31, 2014 and March 31, 2014, respectively.
	The following table is an aging analysis of past due purchased loans as of the dates indicated.
			30-89 Days			90 Days			Total		Current			Total
			Past Due			or More			Past Due					Purchased
														Loans
			(Dollars in thousands)
	March 31, 2015:
	Real estate:
	Residential 1-4 family		$	7,783		$	8,064		$	15,847	$	353,679		$	369,526
	Non-farm/non-residential			6,919			13,138			20,057		1,265,770			1,285,827
	Construction/land development			1,623			4,336			5,959		72,826			78,785
	Agriculture			249			167			416		37,290			37,706
	Multifamily residential			5,375			504			5,879		185,600			191,479
	Commercial and industrial			1,090			627			1,717		54,976			56,693
	Consumer			148			98			246		11,719			11,965
	Other			101			30			131		10,052			10,183
	Total		$	23,288		$	26,964		$	50,252	$	1,991,912		$	2,042,164
	December 31, 2014:
	Real estate:
	Residential 1-4 family		$	8,088		$	9,043		$	17,131	$	338,574		$	355,705
	Non-farm/non-residential			8,907			12,439			21,346		483,543			504,889
	Construction/land development			1,197			5,464			6,661		93,115			99,776
Agriculture			237			875			1,112		46,876			47,988
Multifamily residential			515			67			582		41,852			42,434
Commercial and industrial			863			751			1,614		67,211			68,825
Consumer			199			103			302		14,966			15,268
Other			0			31			31		13,031			13,062
Total		$	20,006		$	28,773		$	48,779	$	1,099,168		$	1,147,947
March 31, 2014:
Real estate:
Residential 1-4 family		$	11,457		$	15,258		$	26,715	$	213,891		$	240,606
Non-farm/non-residential			9,160			29,145			38,305		314,579			352,884
Construction/land development			1,979			16,537			18,516		75,372			93,888
Agriculture			1,129			1,547			2,676		18,451			21,127
Multifamily residential			0			5,139			5,139		21,137			26,276
Commercial and industrial			1,028			1,978			3,006		43,177			46,183
Consumer			179			179			358		6,342			6,700
Other			8			19			27		5,797			5,824
Total		$	24,940		$	69,802		$	94,742	$	698,746		$	793,488

Income_Taxes_Tables

Income Taxes (Tables)	3 Months Ended
	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Types of Temporary Differences Between Tax Basis of Assets and Liabilities	The following table is a summary of the types of temporary differences between the tax basis of assets and liabilities and their financial reporting amounts that give rise to deferred income tax assets and liabilities and their approximate tax effects as of the dates indicated.
		March 31,						December 31,
		2015			2014			2014
		(Dollars in thousands)
	Deferred tax assets:
	Allowance for loan and lease losses	$	20,625		$	16,842		$	20,324
	Differences in amounts reflected in the financial statements and income tax basis of purchased loans not previously covered by FDIC loss share agreements		32,962			18,453			20,444
	Differences in amounts reflected in the financial statements and income tax basis for deposits assumed in acquisitions		8,926			1,157			1,337
	Stock-based compensation		3,807			1,415			3,268
	Deferred compensation		2,069			1,888			1,991
	Foreclosed assets		4,471			4,831			3,503
	Deferred fees and costs on loans and leases		5,244			1,604			4,785
	Investment securities AFS		0			600			0
	Differences in amounts reflected in the financial statements and income tax basis of assets acquired and liabilities assumed in FDIC-assisted acquisitions		8,050			5,393			8,098
	Acquired net operating losses		13,569			13,180			13,332
	Other, net		1,958			2,130			2,568
	Total gross deferred tax assets		101,681			67,493			79,650
	Less valuation allowance		(474	)		(474	)		(474	)
	Net deferred tax asset		101,207			67,019			79,176
	Deferred tax liabilities:
	Accelerated depreciation on premises and equipment		19,114			17,954			18,653
	Investment securities AFS		7,675			0			7,692
	Acquired intangible assets		10,935			5,066			9,743
	Total gross deferred tax liabilities		37,724			23,020			36,088
	Net deferred tax assets	$	63,483		$	43,999		$	43,088

Supplemental_Data_for_Cash_Flo1

Supplemental Data for Cash Flows (Tables)	3 Months Ended
	Mar. 31, 2015
Supplemental Cash Flow Elements [Abstract]
Schedule of Supplemental Cash Flow Information	The following table provides supplemental cash flow information for the periods indicated.
		Three Months Ended
		March 31,
		2015		2014
		(Dollars in thousands)
	Cash paid during the period for:
	Interest	$	6,773	$	4,782
	Taxes		2,029		772
	Supplemental schedule of non-cash investing and financing activities:
	Net change in unrealized gains/losses on investment securities AFS		44		11,325
	Loans and premises and equipment transferred to foreclosed assets		6,746		2,205
	Unsettled AFS investment security purchases		0		2,267
	Common stock issued in merger and acquisition transaction		238,476		0

Guarantees_and_Commitments_Tab

Guarantees and Commitments (Tables)	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Contractual Maturities	The following table shows the contractual maturities of outstanding commitments to extend credit as of the date indicated.
	Contractual Maturities at March 31, 2015
	Maturity	Amount
	(Dollars in thousands)
	2015	$	168,610
	2016		338,819
	2017		1,746,740
	2018		808,907
	2019		92,812
	Thereafter		253,563
	Total	$	3,409,451

Subordinated_Debentures_Tables

Subordinated Debentures (Tables)	3 Months Ended
	Mar. 31, 2015
Brokers and Dealers [Abstract]
Schedule of Issues of Trust Preferred Securities Outstanding and Subordinated Debentures Owed to Trust	At March 31, 2015, the Company had the following issues of trust preferred securities and subordinated debentures owed to the Trusts.
		Subordinated		Unamortized			Carrying		Trust		Contractual
		Debentures		Discount at			Value of		Preferred		Interest
		Owed to		March 31,			Subordinated		Securities		Rate at
		Trust		2015			Debentures		of the		March 31,
							at March 31,		Trusts		2015
							2015
		(Dollars in thousands)
	Ozark II	$	14,434	$	0		$	14,434	$	14,000		3.18	%
	Ozark III		14,433		0			14,433		14,000		3.2
	Ozark IV		15,464		0			15,464		15,000		2.48
	Ozark V		20,619		0			20,619		20,000		1.87
	Intervest II		15,464		(701	)		14,763		15,000		3.22
	Intervest III		15,464		(811	)		14,653		15,000		3.06
	Intervest IV		15,464		(1,475	)		13,989		15,000		2.67
	Intervest V		10,310		(1,401	)		8,909		10,000		1.92
		$	121,652	$	(4,388	)	$	117,264	$	118,000

StockBased_Compensation_Tables

Stock-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Summary of Stock Option Activity	The following table summarizes stock option activity for both the employee and non-employee director stock option plans for the period indicated.
			Options			Weighted-		Weighted-Average		Aggregate
						Average		Remaining		Intrinsic
						Exercise		Contractual Life		Value
						Price/Share		(in years)		(in thousands)
	Three Months Ended March 31, 2015:
	Outstanding – January 1, 2015			1,859,350		$	23.49
	Granted			0			0
	Exercised			(53,000	)		10.3
	Forfeited			(57,900	)		26.85
	Outstanding – March 31, 2015			1,748,450			23.78		5.4	$	22,990	(1)
	Fully vested and exercisable – March 31, 2015			365,600			13.55		4.5	$	8,549	(1)
	Expected to vest in future periods			1,246,680
	Fully vested and expected to vest –			1,612,280			23.13		5.4	$	22,254	(1)
	March 31, 2015 (2)
	-1	Based on closing price of $36.93 per share on March 31, 2015.
	-2	At March 31, 2015, the Company estimated that outstanding options to purchase 136,170 shares of its common stock would not vest and would be forfeited prior to their vesting date.
Summary of Non-Vested Restricted Stock Activity	The following table summarizes non-vested restricted stock activity for the period indicated.
			Three Months Ended
			March 31, 2015
	Outstanding – January 1, 2015			444,700
	Granted			243,300
	Forfeited			(27,250	)
	Vested			0
	Outstanding – March 31, 2015			660,750
	Weighted-average grant date fair value		$	25.22

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Assets and Liabilities at Fair Value	The following table sets forth the Company’s assets, as of the dates indicated, that are accounted for at fair value.
			Level 1			Level 2		Level 3		Total
			(Dollars in thousands)
	March 31, 2015:
	Investment securities AFS (1):
	Obligations of state and political subdivisions		$	0		$	493,140	$	19,067	$	512,207
	U.S. Government agency securities			0			259,975		0		259,975
	Corporate obligations			0			622		0		622
	CRA qualified investment fund			1,028			0		0		1,028
	Total investment securities AFS			1,028			753,737		19,067		773,832
	Impaired non-purchased loans and leases			0			0		12,574		12,574
	Impaired purchased loans			0			0		14,147		14,147
	Foreclosed assets			0			0		32,094		32,094
	Total assets at fair value		$	1,028		$	753,737	$	77,882	$	832,647
	December 31, 2014:
	Investment securities AFS (1):
	Obligations of state and political subdivisions		$	0		$	553,808	$	19,401	$	573,209
	U.S. Government agency securities			0			251,233		0		251,233
	Corporate obligations			0			654		0		654
	Total investment securities AFS			0			805,695		19,401		825,096
	Impaired non-purchased loans and leases			0			0		19,480		19,480
	Impaired purchased loans			0			0		14,040		14,040
	Foreclosed assets			0			0		37,775		37,775
	Total assets at fair value		$	0		$	805,695	$	90,696	$	896,391
	March 31, 2014:
	Investment securities AFS (1):
	Obligations of state and political subdivisions		$	0		$	434,201	$	18,547	$	452,748
	U.S. Government agency securities			0			219,740		0		219,740
	Corporate obligations			0			686		0		686
	Total investment securities AFS			0			654,627		18,547		673,174
	Impaired non-purchased loans and leases			0			0		5,978		5,978
	Impaired purchased loans			0			0		29,332		29,332
	Foreclosed assets			0			0		60,869		60,869
	Total assets at fair value		$	0		$	654,627	$	114,726	$	769,353
	-1	Does not include $10.4 million at March 31, 2015; $14.2 million at December 31, 2014 and $14.5 million at March 31, 2014 of FHLB and FNBB equity securities that do not have readily determinable fair values and are carried at cost.
Schedule of Information Related to Level 3 Non-Recurring Fair Value Measurements	The following table presents information related to Level 3 non-recurring fair value measurements as of the date indicated.
	Description		Fair Value at		Technique	Unobservable Inputs
			March 31, 2015
	(Dollars in thousands)
	Impaired non-purchased loans and leases		$12,574		Third party appraisal(1) or discounted cash flows	1. Management discount based on underlying collateral characteristics and market conditions
						2. Life of loan
	Impaired purchased loans		$14,147		Third party appraisal(1) and/or discounted cash flows	1. Management discount based on underlying collateral characteristics and market conditions
						2. Life of loan
	Foreclosed assets		$32,094		Third party appraisal,(1) broker price opinions and/or discounted cash flows	1. Management discount based on asset characteristics and market conditions
						2. Discount rate
						3. Holding period
	-1	The Company utilizes valuation techniques consistent with the market, cost, and income approaches, or a combination thereof in determining fair value.
Assets Measured at Fair Value on Recurring Basis Utilizing Level 3 Inputs	The following table presents additional information for the periods indicated about assets measured at fair value on a recurring basis and for which the Company has utilized Level 3 inputs to determine fair value.
			Investment
			Securities AFS
			(Dollars in thousands)
	Balance – January 1, 2015		$	19,401
	Total realized gains (losses) included in earnings			0
	Total unrealized gains (losses) included in comprehensive income			(87	)
	Paydowns and maturities			(247	)
	Sales			0
	Transfers in and/or out of Level 3			0
	Balance – March 31, 2015		$	19,067
	Balance – January 1, 2014		$	18,682
	Total realized gains (losses) included in earnings			0
	Total unrealized gains (losses) included in comprehensive income			248
	Paydowns and maturities			(383	)
	Sales			0
	Transfers in and/or out of Level 3			0
	Balance – March 31, 2014		$	18,547

Fair_Value_of_Financial_Instru1

Fair Value of Financial Instruments (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Estimated Fair Values of Financial Instruments	The following table presents the carrying amounts and estimated fair values for the dates indicated and the fair value hierarchy of the Company’s financial instruments.
			March 31,
			2015				2014				December 31, 2014
		Fair	Carrying		Estimated		Carrying		Estimated		Carrying		Estimated
		Value	Amount		Fair		Amount		Fair		Amount		Fair
		Hierarchy			Value				Value				Value
			(Dollars in thousands)
	Financial assets:
	Cash and cash equivalents	Level 1	$	425,794	$	425,794	$	188,351	$	188,351	$	150,203	$	150,203
	Investment securities AFS	Levels 1, 2 and 3		784,725		784,725		687,661		687,661		839,321		839,321
	Loans and leases, net of ALLL	Level 3		6,299,122		6,230,658		3,528,130		3,496,946		5,074,899		5,042,831
	FDIC loss share receivable	Level 3		0		0		57,782		57,722		0		0
	Financial liabilities:
	Demand, savings and interest bearing transaction deposits	Level 1	$	4,563,972	$	4,563,972	$	3,085,886	$	3,085,886	$	4,038,443	$	4,038,443
	Time deposits	Level 2		2,152,689		2,158,211		830,318		830,583		1,457,939		1,463,590
	Repurchase agreements with customers	Level 1		76,960		76,960		51,140		51,140		65,578		65,578
	Other borrowings	Level 2		161,318		172,180		280,885		317,186		190,855		203,493
	FDIC clawback payable	Level 3		0		0		26,202		26,202		0		0
	Subordinated debentures	Level 2		117,264		71,442		64,950		32,767		64,950		39,103

Changes_In_and_Reclassificatio1

Changes In and Reclassifications From Accumulated Other Comprehensive Income ("AOCI") (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Changes in Accumulated Other Comprehensive Income	The following table presents changes in AOCI for the periods indicated.
		Three Months Ended
		March 31,
		2015			2014
		(Dollars in thousands)
	Beginning balance of AOCI – unrealized gains and losses on investment securities AFS	$	14,132		$	(3,672	)
	Other comprehensive income (loss):
	Unrealized gains and losses on investment securities AFS		2,914			11,330
	Tax effect of unrealized gains and losses on investment securities AFS		(1,110	)		(4,444	)
	Amounts reclassified from AOCI		(2,534	)		(5	)
	Tax effect of amounts reclassified from AOCI		965			2
	Total other comprehensive income (loss)		235			6,883
	Ending balance of AOCI – unrealized gains and losses on investment securities AFS	$	14,367		$	3,211

Other_Operating_Expenses_Table

Other Operating Expenses (Tables)	3 Months Ended
	Mar. 31, 2015
Other Income and Expenses [Abstract]
Schedule of Other Operating Expenses	The following table is a summary of other operating expenses for the periods indicated.
		Three Months Ended
		March 31,
		2015		2014
		(Dollars in thousands)
	Salaries and employee benefits	$	22,597	$	17,689
	Net occupancy and equipment		7,291		5,044
	Other operating expenses:
	Postage and supplies		915		770
	Advertising and public relations		583		400
	Telecommunication services		1,348		1,001
	Professional and outside services		4,386		2,128
	Software and data processing		749		6,024
	Travel and meals		796		556
	FDIC insurance		750		503
	FDIC and state assessments		310		260
	ATM expense		708		210
	Loan collection and repossession expense		1,733		460
	Writedowns of foreclosed and other assets		2,192		64
	Amortization of intangibles		1,596		813
	FHLB prepayment penalty		2,480		0
	Other		1,750		1,532
	Total non-interest expense	$	50,184	$	37,454

Organization_and_Principles_of1

Organization and Principles of Consolidation - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015
	Office
	Trust
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Ownership interest owned finance subsidiary business trusts	100.00%
Number of finance subsidiary trusts	8
Number of offices	165
Arkansas [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	81
Georgia [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	28
North Carolina [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	16
Texas [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	21
Florida [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	11
Alabama [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	3
South Carolina [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	2
New York [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	2
California [Member]
Organization Consolidation And Presentation Of Financial Statements [Line Items]
Number of offices	1

Basis_of_Presentation_Addition

Basis of Presentation - Additional Information (Detail)	0 Months Ended
	Jun. 23, 2014
Accounting Policies [Abstract]
Conversion ratio of stock split	2
Number of shares effected by issuing shares, stock split	1

Acquisitions_Additional_Inform

Acquisitions - Additional Information (Detail) (USD $)	3 Months Ended			0 Months Ended	3 Months Ended	0 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	16-May-14	Jun. 30, 2014	Feb. 10, 2015	Mar. 05, 2014
		Office			Office
Net interest income	$85,489,000		$52,396,000
Net income	39,918,000		25,268,000
Number of banking offices closed		7
Summit Bancorp, Inc. [Member]
Number of common stock issued				5,765,846
Date of acquisition				16-May-14
Goodwill	73,400,000
Cash consideration				42,500,000
Number of banking offices closed		5			1
Number of loan production office closed					1
Intervest Bancshares Corporation [Member]
Number of common stock issued						6,637,243
Total Cash consideration						238,500,000
Date of acquisition	10-Feb-15
Goodwill	46,900,000
Net interest income	8,900,000
Net income	4,800,000
Bancshares Inc [Member]
Date of acquisition							5-Mar-14
Cash consideration							21,500,000
Bargain purchase gain recognized amount			$4,700,000
Central South And Western Arkansas [Member] | Summit Bancorp, Inc. [Member]
Number of bank offices				23
Arkansas Counties [Member] | Summit Bancorp, Inc. [Member]
Number of loan production office				1
Number of Arkansas countries				9
Clearwater [Member] | Intervest National Bank (INB) [Member]
Number of bank offices	5
Pasadena [Member] | Intervest National Bank (INB) [Member]
Number of bank offices	1
New York [Member] | Intervest National Bank (INB) [Member]
Number of bank offices	1
Houston [Member] | Bancshares Inc [Member]
Number of bank offices							3
Austin [Member] | Bancshares Inc [Member]
Number of bank offices							1
Cedar Park [Member] | Bancshares Inc [Member]
Number of bank offices							1
Lockhart [Member] | Bancshares Inc [Member]
Number of bank offices							1
San Antonio [Member] | Bancshares Inc [Member]
Number of bank offices							1

Acquisitions_Summary_of_Assets

Acquisitions - Summary of Assets Acquired and Liabilities Assumed in Acquisition (Detail) (USD $)	3 Months Ended	0 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Feb. 10, 2015
Business Combination, Separately Recognized Transactions [Line Items]
Common Stock	($238,376)
Intervest Bancshares Corporation [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash, due from banks and interest earning deposits		274,343
Investment securities		21,495
Loans		1,108,439
Allowance for loan losses		-25,208
Premises and equipment		4,357
Foreclosed assets		2,350
Accrued interest receivable and other assets		34,076
Core deposit intangible asset		0
Deferred income taxes		11,758
Total assets acquired		1,431,610
Deposits		1,162,437
Subordinated debentures		56,702
Accrued interest payable and other liabilities		3,608
Total liabilities assumed		1,222,747
Net assets acquired		208,863
Goodwill	46,900
Preliminary Fair Value Adjustments Intervest Bancshares Corporation [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash, due from banks and interest earning deposits		0	[1]
Investment securities		321	[1],[2]
Loans		-33,868	[1],[3]
Allowance for loan losses		25,208	[1],[3]
Premises and equipment		2,256	[1],[4]
Foreclosed assets		-1,710	[1],[5]
Accrued interest receivable and other assets		-4,091	[1],[6]
Core deposit intangible asset		4,595	[1],[7]
Deferred income taxes		8,082	[1],[8]
Total assets acquired		793	[1]
Deposits		22,211	[1],[9]
Subordinated debentures		-4,463	[1],[10]
Accrued interest payable and other liabilities		358	[1],[11]
Total liabilities assumed		18,106	[1]
Net assets acquired		-17,313	[1]
As recorded by the Company [Member]
Business Combination, Separately Recognized Transactions [Line Items]
Cash, due from banks and interest earning deposits		274,343	[1]
Investment securities		21,816	[1]
Loans		1,074,571	[1]
Allowance for loan losses		0	[1]
Premises and equipment		6,613	[1]
Foreclosed assets		640	[1]
Accrued interest receivable and other assets		29,985	[1]
Core deposit intangible asset		4,595	[1]
Deferred income taxes		19,840	[1]
Total assets acquired		1,432,403	[1]
Deposits		1,184,648	[1]
Subordinated debentures		52,239	[1]
Accrued interest payable and other liabilities		3,966	[1]
Total liabilities assumed		1,240,853	[1]
Net assets acquired		191,550	[1]
Cash in lieu of fractional shares		-7	[1]
Common Stock		-238,476	[1]
Total consideration paid		-238,483	[1]
Goodwill		$46,933	[1]
[1]	The acquisition of Intervest closed on February 10, 2015. Accordingly, each of the fair value adjustments shown are preliminary estimates of the purchase accounting adjustments. Management is continuing to evaluate each of these fair value adjustments and may revise one or more of such fair value adjustments in future periods based on this continuing evaluation. To the extent that any of these preliminary fair value adjustments are revised in future periods, the resultant fair values and the amount of goodwill could change.
[2]	Adjustment reflects the fair value adjustment based on the pricing of the acquired investment securities portfolio.
[3]	Adjustment reflects the fair value adjustment based on the evaluation of the acquired loan portfolio and to eliminate the recorded allowance for loan losses.
[4]	Adjustment reflects the fair value adjustment based on the evaluation of the premises and equipment acquired.
[5]	Adjustment reflects the fair value adjustment based on the evaluation of the acquired foreclosed assets.
[6]	Adjustment reflects the fair value adjustment based on the evaluation of accrued interest receivable and other assets.
[7]	Adjustment reflects the fair value adjustment for the core deposit intangible asset recorded as a result of the acquisition.
[8]	This adjustment reflects the differences in the carrying values of acquired assets and assumed liabilities for financial reporting purposes and their basis for federal income tax purposes.
[9]	Adjustment reflects the fair value adjustment based on the evaluation of the acquired deposits.
[10]	Adjustment reflects the fair value adjustment of these assumed liabilities based on a valuation of such instruments by an independent, third party valuation firm.
[11]	Adjustment reflects the amount needed to adjust other liabilities to estimated fair value and to record certain liabilities directly attributable to the Intervest acquisition.

Acquisitions_Summary_of_Supple

Acquisitions - Summary of Supplemental Pro-forma Information (Detail) (Intervest Bancshares Corporation [Member], USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Intervest Bancshares Corporation [Member]
Pro-forma Information [Line Items]
Net interest income - pro forma (unaudited)	$90,345	$67,947
Net income - pro forma (unaudited)	$43,924	$30,504
Diluted earnings per common share - pro forma (unaudited)	$0.50	$0.38

Earnings_Per_Common_Share_EPS_1

Earnings Per Common Share ("EPS") - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Options to purchase shares of the Company's common stock	535,000	0
Weighted-average exercise price outstanding	$36.05

Earnings_Per_Common_Share_EPS_2

Earnings Per Common Share ("EPS") - Schedule of Calculation of Numerator and Denominator in Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Distributed earnings allocated to common stock	$10,413	$8,108
Undistributed earnings allocated to common stock	29,481	17,168
Net income available to common stockholders	$39,894	$25,276
Denominator for basic EPS - weighted-average common shares	83,699	73,802
Effect of dilutive securities - stock options	710	692
Denominator for diluted EPS - weighted-average common shares and assumed conversions	84,409	74,494
Basic EPS	$0.48	$0.34
Diluted EPS	$0.47	$0.34

Investment_Securities_Summary_

Investment Securities - Summary of Amortized Cost and Estimated Fair Values of Investment Securities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$761,066	$816,068	$682,377
Gross Unrealized Gains	23,712	24,411	13,536
Gross Unrealized Losses	-503	-1,158	-8,252
Estimated Fair Value	784,275	839,321	687,661
Obligations of State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	496,251	555,335	447,368
Gross Unrealized Gains	16,203	18,267	10,010
Gross Unrealized Losses	-247	-393	-4,630
Estimated Fair Value	512,207	573,209	452,748
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	252,728	245,854	219,836
Gross Unrealized Gains	7,503	6,144	3,526
Gross Unrealized Losses	-256	-765	-3,622
Estimated Fair Value	259,975	251,233	219,740
Corporate Obligations [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	622	654	686
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	0	0
Estimated Fair Value	622	654	686
CRA Qualified Investment Fund [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	1,022
Gross Unrealized Gains	6
Gross Unrealized Losses	0
Estimated Fair Value	1,028
FHLB and FNBB Equity Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	10,443	14,225	14,487
Gross Unrealized Gains	0	0	0
Gross Unrealized Losses	0	0	0
Estimated Fair Value	$10,443	$14,225	$14,487

Investment_Securities_Gross_Un

Investment Securities - Gross Unrealized Losses and Estimated Fair Value of Investment Securities (Detail) (USD $)	3 Months Ended		12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Available-for-sale Securities [Line Items]
Total temporarily impaired investment securities, Estimated Fair Value, Less than 12 Months	$62,563	$121,744	$38,804
Total temporarily impaired investment securities, Unrealized Losses, Less than 12 Months	360	5,630	100
Total temporarily impaired investment securities, Estimated Fair Value, 12 Months or More	10,678	48,928	82,040
Total temporarily impaired investment securities, Unrealized Losses, 12 Months or More	143	2,622	1,058
Total temporarily impaired securities, Estimated Fair Value, Total	73,241	170,672	120,844
Total temporarily impaired securities, Unrealized Losses, Total	503	8,252	1,158
Obligations of State and Political Subdivisions [Member]
Schedule of Available-for-sale Securities [Line Items]
Total temporarily impaired investment securities, Estimated Fair Value, Less than 12 Months	39,112	51,961	29,174
Total temporarily impaired investment securities, Unrealized Losses, Less than 12 Months	189	2,048	75
Total temporarily impaired investment securities, Estimated Fair Value, 12 Months or More	3,437	47,890	34,414
Total temporarily impaired investment securities, Unrealized Losses, 12 Months or More	58	2,582	318
Total temporarily impaired securities, Estimated Fair Value, Total	42,549	99,851	63,588
Total temporarily impaired securities, Unrealized Losses, Total	247	4,630	393
U.S. Government Agency Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Total temporarily impaired investment securities, Estimated Fair Value, Less than 12 Months	23,451	69,783	9,630
Total temporarily impaired investment securities, Unrealized Losses, Less than 12 Months	171	3,582	25
Total temporarily impaired investment securities, Estimated Fair Value, 12 Months or More	7,241	1,038	47,626
Total temporarily impaired investment securities, Unrealized Losses, 12 Months or More	85	40	740
Total temporarily impaired securities, Estimated Fair Value, Total	30,692	70,821	57,256
Total temporarily impaired securities, Unrealized Losses, Total	$256	$3,622	$765

Investment_Securities_Amortize

Investment Securities - Amortized Cost and Estimated Fair Value of Investment Securities AFS by Maturity or Estimated Date of Repayment (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Investments, Debt and Equity Securities [Abstract]
Amortized Cost, One year or less	$37,328
Amortized Cost, After one year to five years	139,542
Amortized Cost, After five years to ten years	187,370
Amortized Cost, After ten years	396,826
Total, Amortized Cost	761,066
Estimated Fair Value, One year or less	38,391
Estimated Fair Value, After one year to five years	142,725
Estimated Fair Value, After five years to ten years	192,169
Estimated Fair Value, After ten years	410,990
Total, Estimated Fair Value	$784,275

Investment_Securities_Sales_Ac

Investment Securities - Sales Activities of Company's Investment Securities AFS are Summarized (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Sales proceeds	$30,117	$1,224
Gross realized gains	2,535	5
Gross realized losses	-1	0
Net gains on investment securities	$2,534	$5

Allowance_for_Loan_and_Lease_L2

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Schedule of Impaired Non-purchased Loans and Leases, FDIC Loss Share Agreements (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Beginning balance	$52,918,000	$42,945,000	$42,945,000
Principal Balance	16,487,000	12,088,000	25,347,000
Non-purchased loans and leases charged off	-4,079,000	-920,000
Net Charge-offs to Date	-3,549,000	-4,824,000	-4,772,000
Recoveries of non-purchased loans and leases previously charged off	308,000	736,000
Principal Balance, Net of Charge-offs	12,938,000	7,264,000	20,575,000
Net charge-offs	-5,086,000	-388,000
Total provision	6,315,000	1,304,000
Ending balance	54,147,000	43,861,000	52,918,000
Principal Balance, with Related Allowance	4,017,000	5,221,000	9,960,000
Net Charge-offs to Date, with Related Allowance	-2,632,000	-2,770,000	-3,165,000
Principal Balance, with Related Allowance, Net of Charge-offs	1,385,000	2,451,000	6,795,000
Specific Allowance	363,000	1,286,000	1,095,000
Weighted Average Carrying Value, with Related Allowance	4,090,000	2,774,000	3,499,000
Weighted Average Carrying Value	16,757,000	7,675,000	15,275,000
Principal Balance, with no Related Allowance	12,470,000	6,867,000	15,387,000
Net Charge-offs to Date, with no Related Allowance	-917,000	-2,054,000	-1,607,000
Principal Balance, with no Related Allowance, Net of Charge-offs	11,553,000	4,813,000	13,780,000
Weighted Average Carrying Value, with no Related Allowance	12,667,000	4,901,000	11,776,000
Non Purchase Loan [Member]
Financing Receivable, Impaired [Line Items]
Net charge-offs	-3,771,000	-184,000
Total provision	5,000,000	1,100,000
Purchased Loans [Member]
Financing Receivable, Impaired [Line Items]
Net charge-offs	-1,315,000	-204,000
Total provision	1,315,000	204,000
Real Estate [Member] | Residential 1-4 Family [Member]
Financing Receivable, Impaired [Line Items]
Principal Balance, with Related Allowance	3,123,000	3,164,000	3,163,000
Net Charge-offs to Date, with Related Allowance	-1,814,000	-1,726,000	-1,674,000
Principal Balance, with Related Allowance, Net of Charge-offs	1,309,000	1,438,000	1,489,000
Specific Allowance	295,000	385,000	356,000
Weighted Average Carrying Value, with Related Allowance	1,399,000	1,677,000	1,457,000
Principal Balance, with no Related Allowance	1,379,000	2,845,000	1,373,000
Net Charge-offs to Date, with no Related Allowance	-179,000	-472,000	-128,000
Principal Balance, with no Related Allowance, Net of Charge-offs	1,200,000	2,373,000	1,245,000
Weighted Average Carrying Value, with no Related Allowance	1,223,000	2,252,000	1,581,000
Real Estate [Member] | Non-Farm/Non-Residential [Member]
Financing Receivable, Impaired [Line Items]
Principal Balance, with Related Allowance	184,000	188,000	762,000
Net Charge-offs to Date, with Related Allowance	-142,000	-127,000	-220,000
Principal Balance, with Related Allowance, Net of Charge-offs	42,000	61,000	542,000
Specific Allowance	10,000	29,000	18,000
Weighted Average Carrying Value, with Related Allowance	292,000	53,000	211,000
Principal Balance, with no Related Allowance	633,000	2,702,000	2,676,000
Net Charge-offs to Date, with no Related Allowance	-137,000	-1,136,000	-711,000
Principal Balance, with no Related Allowance, Net of Charge-offs	496,000	1,566,000	1,965,000
Weighted Average Carrying Value, with no Related Allowance	1,231,000	1,840,000	1,988,000
Real Estate [Member] | Construction/Land Development [Member]
Financing Receivable, Impaired [Line Items]
Principal Balance, with Related Allowance	38,000	38,000	4,656,000
Net Charge-offs to Date, with Related Allowance	-22,000	-22,000	-545,000
Principal Balance, with Related Allowance, Net of Charge-offs	16,000	16,000	4,111,000
Specific Allowance	2,000	2,000	68,000
Weighted Average Carrying Value, with Related Allowance	2,064,000	16,000	1,040,000
Principal Balance, with no Related Allowance	9,500,000	390,000	10,378,000
Net Charge-offs to Date, with no Related Allowance	-102,000	-81,000	-185,000
Principal Balance, with no Related Allowance, Net of Charge-offs	9,398,000	309,000	10,193,000
Weighted Average Carrying Value, with no Related Allowance	9,796,000	264,000	7,600,000
Real Estate [Member] | Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Principal Balance, with Related Allowance	0	360,000	105,000
Net Charge-offs to Date, with Related Allowance	0	-12,000	-12,000
Principal Balance, with Related Allowance, Net of Charge-offs	0	348,000	93,000
Specific Allowance	0	243,000	6,000
Weighted Average Carrying Value, with Related Allowance	46,000	409,000	217,000
Principal Balance, with no Related Allowance	507,000	513,000	474,000
Net Charge-offs to Date, with no Related Allowance	-202,000	-44,000	-202,000
Principal Balance, with no Related Allowance, Net of Charge-offs	305,000	469,000	272,000
Weighted Average Carrying Value, with no Related Allowance	288,000	441,000	383,000
Real Estate [Member] | Multifamily Residential [Member]
Financing Receivable, Impaired [Line Items]
Principal Balance, with no Related Allowance	133,000	133,000	133,000
Net Charge-offs to Date, with no Related Allowance	-133,000	-133,000	-133,000
Principal Balance, with no Related Allowance, Net of Charge-offs	0	0	0
Weighted Average Carrying Value, with no Related Allowance	0	0	123,000
Commercial and Industrial [Member]
Financing Receivable, Impaired [Line Items]
Beginning balance	4,873,000	2,855,000	2,855,000
Ending balance	3,301,000	2,738,000	4,873,000
Principal Balance, with Related Allowance	632,000	1,368,000	1,233,000
Net Charge-offs to Date, with Related Allowance	-631,000	-803,000	-691,000
Principal Balance, with Related Allowance, Net of Charge-offs	1,000	565,000	542,000
Specific Allowance	53,000	624,000	644,000
Weighted Average Carrying Value, with Related Allowance	0	588,000	554,000
Principal Balance, with no Related Allowance	290,000	220,000	264,000
Net Charge-offs to Date, with no Related Allowance	-159,000	-159,000	-183,000
Principal Balance, with no Related Allowance, Net of Charge-offs	131,000	61,000	81,000
Weighted Average Carrying Value, with no Related Allowance	106,000	68,000	75,000
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Beginning balance	818,000	917,000	917,000
Ending balance	824,000	831,000	818,000
Principal Balance, with Related Allowance	40,000	103,000	41,000
Net Charge-offs to Date, with Related Allowance	-23,000	-80,000	-23,000
Principal Balance, with Related Allowance, Net of Charge-offs	17,000	23,000	18,000
Specific Allowance	3,000	3,000	3,000
Weighted Average Carrying Value, with Related Allowance	271,000	23,000	20,000
Principal Balance, with no Related Allowance	20,000	34,000	81,000
Net Charge-offs to Date, with no Related Allowance	-5,000	-9,000	-65,000
Principal Balance, with no Related Allowance, Net of Charge-offs	15,000	25,000	16,000
Weighted Average Carrying Value, with no Related Allowance	15,000	26,000	18,000
Other [Member]
Financing Receivable, Impaired [Line Items]
Beginning balance	901,000	763,000	763,000
Ending balance	812,000	944,000	901,000
Principal Balance, with Related Allowance	0	0
Net Charge-offs to Date, with Related Allowance	0	0
Principal Balance, with Related Allowance, Net of Charge-offs	0	0
Specific Allowance	0	0
Weighted Average Carrying Value, with Related Allowance	18,000	8,000
Principal Balance, with no Related Allowance	8,000	30,000	8,000
Net Charge-offs to Date, with no Related Allowance	0	-20,000	0
Principal Balance, with no Related Allowance, Net of Charge-offs	8,000	10,000	8,000
Weighted Average Carrying Value, with no Related Allowance	$8,000	$10,000	$8,000

Allowance_for_Loan_and_Lease_L3

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Partial charge-offs, net of adjustments to FDIC loss share receivable and FDIC clawback payable	$1,300,000	$200,000
Provision for covered loan and lease losses	1,300,000	200,000
Impaired Purchased Loans	14,100,000	29,300,000	14,000,000
Allowance for Loan and Lease Losses	54,147,000	43,861,000	52,918,000	42,945,000
Non-Covered Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Allowance for Loan and Lease Losses	$0	$0	$0

Allowance_for_Loan_and_Lease_L4

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Summary of Company's Allowance for Loan and Lease Losses (Detail) (USD $)	3 Months Ended		12 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$52,918,000	$42,945,000	$42,945,000
Charge-offs	-5,394,000	-1,124,000	-8,338,000
Recoveries	308,000	736,000	1,396,000
Provision	6,315,000	1,304,000	16,915,000
Ending balance	54,147,000	43,861,000	52,918,000
Real Estate [Member] | Residential 1-4 Family [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	5,482,000	4,701,000	4,701,000
Charge-offs	-529,000	-199,000	-577,000
Recoveries	11,000	22,000	135,000
Provision	693,000	98,000	1,223,000
Ending balance	5,657,000	4,622,000	5,482,000
Real Estate [Member] | Non-Farm/Non-Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	17,190,000	13,633,000	13,633,000
Charge-offs	-205,000	-73,000	-1,357,000
Recoveries	12,000	3,000	33,000
Provision	769,000	450,000	4,881,000
Ending balance	17,766,000	14,013,000	17,190,000
Real Estate [Member] | Construction/Land Development [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	15,960,000	12,306,000	12,306,000
Charge-offs	-302,000	0	-638,000
Recoveries	37,000	8,000	11,000
Provision	1,885,000	514,000	4,281,000
Ending balance	17,580,000	12,828,000	15,960,000
Real Estate [Member] | Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	2,558,000	3,000,000	3,000,000
Charge-offs	-13,000	-15,000	-214,000
Recoveries	0	5,000	14,000
Provision	-19,000	28,000	-242,000
Ending balance	2,526,000	3,018,000	2,558,000
Real Estate [Member] | Multifamily Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	2,147,000	2,504,000	2,504,000
Charge-offs	0	0	0
Recoveries	0	0	0
Provision	276,000	-75,000	-357,000
Ending balance	2,423,000	2,429,000	2,147,000
Commercial and Industrial [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	4,873,000	2,855,000	2,855,000
Charge-offs	-2,447,000	-374,000	-720,000
Recoveries	16,000	628,000	808,000
Provision	859,000	-371,000	1,930,000
Ending balance	3,301,000	2,738,000	4,873,000
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	818,000	917,000	917,000
Charge-offs	-45,000	-41,000	-222,000
Recoveries	21,000	18,000	80,000
Provision	30,000	-63,000	43,000
Ending balance	824,000	831,000	818,000
Direct Financing Leases [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	2,989,000	2,266,000	2,266,000
Charge-offs	-186,000	-146,000	-602,000
Recoveries	6,000	6,000	49,000
Provision	449,000	312,000	1,276,000
Ending balance	3,258,000	2,438,000	2,989,000
Other [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	901,000	763,000	763,000
Charge-offs	-352,000	-72,000	-793,000
Recoveries	205,000	46,000	266,000
Provision	58,000	207,000	665,000
Ending balance	812,000	944,000	901,000
Purchased Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	0	0	0
Charge-offs	-1,315,000	-204,000	-3,215,000
Recoveries	0	0	0
Provision	1,315,000	204,000	3,215,000
Ending balance	$0	$0	$0

Allowance_for_Loan_and_Lease_L5

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Summary of Allowance for Loan and Lease Losses and Recorded Investment in Non-Purchased Loans and Leases (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	$363,000	$1,095,000	$1,286,000
Total ALLL	54,147,000	52,918,000	43,861,000	42,945,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	12,938,000	20,575,000	7,264,000
Non-Purchased Loans and Leases - All Other Loans and Leases	4,298,167,000	3,959,295,000	2,771,239,000
Total non-purchased loans and leases	4,311,105,000	3,979,870,000	2,778,503,000
Real Estate [Member] | Residential 1-4 Family [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	295,000	356,000	385,000
Total ALLL	5,657,000	5,482,000	4,622,000	4,701,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	2,509,000	2,734,000	3,811,000
Non-Purchased Loans and Leases - All Other Loans and Leases	301,326,000	280,519,000	248,977,000
Total non-purchased loans and leases	303,835,000	283,253,000	252,788,000
Real Estate [Member] | Non-Farm/Non-Residential [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	10,000	18,000	29,000
Total ALLL	17,766,000	17,190,000	14,013,000	13,633,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	538,000	2,507,000	1,627,000
Non-Purchased Loans and Leases - All Other Loans and Leases	1,574,413,000	1,501,034,000	1,142,856,000
Total non-purchased loans and leases	1,574,951,000	1,503,541,000	1,144,483,000
Real Estate [Member] | Construction/Land Development [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	2,000	68,000	2,000
Total ALLL	17,580,000	15,960,000	12,828,000	12,306,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	9,413,000	14,304,000	325,000
Non-Purchased Loans and Leases - All Other Loans and Leases	1,650,924,000	1,397,534,000	795,801,000
Total non-purchased loans and leases	1,660,337,000	1,411,838,000	796,126,000
Real Estate [Member] | Agricultural [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	0	6,000	243,000
Total ALLL	2,526,000	2,558,000	3,018,000	3,000,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	305,000	365,000	817,000
Non-Purchased Loans and Leases - All Other Loans and Leases	48,879,000	46,870,000	43,091,000
Total non-purchased loans and leases	49,184,000	47,235,000	43,908,000
Real Estate [Member] | Multifamily Residential [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	0	0	0
Total ALLL	2,423,000	2,147,000	2,429,000	2,504,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	0	0	0
Non-Purchased Loans and Leases - All Other Loans and Leases	228,973,000	211,156,000	195,332,000
Total non-purchased loans and leases	228,973,000	211,156,000	195,332,000
Commercial and Industrial [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	53,000	644,000	624,000
Total ALLL	3,301,000	4,873,000	2,738,000	2,855,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	131,000	623,000	626,000
Non-Purchased Loans and Leases - All Other Loans and Leases	252,947,000	287,084,000	137,038,000
Total non-purchased loans and leases	253,078,000	287,707,000	137,664,000
Consumer [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	3,000	3,000	3,000
Total ALLL	824,000	818,000	831,000	917,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	33,000	34,000	48,000
Non-Purchased Loans and Leases - All Other Loans and Leases	24,836,000	25,635,000	23,721,000
Total non-purchased loans and leases	24,869,000	25,669,000	23,769,000
Direct Financing Leases [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	0	0	0
Total ALLL	3,258,000	2,989,000	2,438,000	2,266,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	0	0	0
Non-Purchased Loans and Leases - All Other Loans and Leases	126,326,000	115,475,000	92,856,000
Total non-purchased loans and leases	126,326,000	115,475,000	92,856,000
Other [Member]
Allowance For Loan And Lease Losses [Line Items]
ALLL for Individually Evaluated Impaired Loans and Leases	0	0	0
Total ALLL	812,000	901,000	944,000	763,000
Non-Purchased Loans and Leases - Individually Evaluated Impaired Loans and Leases	9,000	8,000	10,000
Non-Purchased Loans and Leases - All Other Loans and Leases	89,543,000	93,988,000	91,567,000
Total non-purchased loans and leases	89,552,000	93,996,000	91,577,000
ALLL for All Other Loans and Leases [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	53,784,000	51,823,000	42,575,000
ALLL for All Other Loans and Leases [Member] | Real Estate [Member] | Residential 1-4 Family [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	5,362,000	5,126,000	4,237,000
ALLL for All Other Loans and Leases [Member] | Real Estate [Member] | Non-Farm/Non-Residential [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	17,756,000	17,172,000	13,984,000
ALLL for All Other Loans and Leases [Member] | Real Estate [Member] | Construction/Land Development [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	17,578,000	15,892,000	12,826,000
ALLL for All Other Loans and Leases [Member] | Real Estate [Member] | Agricultural [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	2,526,000	2,552,000	2,775,000
ALLL for All Other Loans and Leases [Member] | Real Estate [Member] | Multifamily Residential [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	2,423,000	2,147,000	2,429,000
ALLL for All Other Loans and Leases [Member] | Commercial and Industrial [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	3,248,000	4,229,000	2,114,000
ALLL for All Other Loans and Leases [Member] | Consumer [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	821,000	815,000	828,000
ALLL for All Other Loans and Leases [Member] | Direct Financing Leases [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	3,258,000	2,989,000	2,438,000
ALLL for All Other Loans and Leases [Member] | Other [Member]
Allowance For Loan And Lease Losses [Line Items]
Total ALLL	$812,000	$901,000	$944,000

Allowance_for_Loan_and_Lease_L6

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Summary of Credit Quality Indicators for Loans and Leases, Including Purchased and Non-Purchased Loans and Leases (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Loans And Leases [Line Items]
Total non-purchased loans and leases	$4,311,105	$3,979,870	$2,778,503
Total purchased Loans	2,042,164	1,147,947	793,488
Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	360,147	321,718	115,393
Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,055,352	355,203	189,620
Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	213,268	76,946	76,541
Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	100,175	116,852	49,360
Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,337	748	0
Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	299,075	263,188	333,242
Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	12,810	13,292	29,332
Real Estate [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,963,323	1,050,792	734,781
Real Estate [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	338,883	294,928	101,975
Real Estate [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,030,387	326,053	172,055
Real Estate [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	208,097	71,029	70,542
Real Estate [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	82,411	92,710	42,447
Real Estate [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,312	723	0
Real Estate [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	289,889	252,620	318,564
Real Estate [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	12,344	12,729	29,198
Real Estate [Member] | Residential 1-4 Family [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	303,835	283,253	252,788
Total purchased Loans	369,526	355,705	240,606
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	67,490	73,196	27,899
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	107,772	81,840	37,442
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	33,991	30,180	21,933
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	64,957	71,687	34,004
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	158	151	0
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	92,829	96,752	115,707
Real Estate [Member] | Residential 1-4 Family [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	2,329	1,899	3,621
Real Estate [Member] | Non-Farm/Non-Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,574,951	1,503,541	1,144,483
Total purchased Loans	1,285,827	504,889	352,884
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	227,184	166,754	59,720
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	759,926	180,522	102,836
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	135,766	32,157	32,160
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	4,353	4,906	2,701
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	256	505	0
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	151,342	114,217	140,933
Real Estate [Member] | Non-Farm/Non-Residential [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	7,000	5,828	14,534
Real Estate [Member] | Construction/Land Development [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,660,337	1,411,838	796,126
Total purchased Loans	78,785	99,776	93,888
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	11,613	21,803	9,880
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	20,647	26,858	18,384
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	7,160	4,312	10,605
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	8,553	13,708	4,550
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	725	0	0
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	27,072	28,497	40,075
Real Estate [Member] | Construction/Land Development [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	3,015	4,598	10,394
Real Estate [Member] | Agricultural [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	49,184	47,235	43,908
Total purchased Loans	37,706	47,988	21,127
Real Estate [Member] | Agricultural [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	8,815	10,444	1,260
Real Estate [Member] | Agricultural [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	19,105	25,187	7,490
Real Estate [Member] | Agricultural [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,937	2,409	842
Real Estate [Member] | Agricultural [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,025	1,525	146
Real Estate [Member] | Agricultural [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	108	0	0
Real Estate [Member] | Agricultural [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	6,716	8,331	11,050
Real Estate [Member] | Agricultural [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	0	92	339
Real Estate [Member] | Multifamily Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	228,973	211,156	195,332
Total purchased Loans	191,479	42,434	26,276
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	23,781	22,731	3,216
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	122,937	11,646	5,903
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	29,243	1,971	5,002
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	3,523	884	1,046
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	65	67	0
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	11,930	4,823	10,799
Real Estate [Member] | Multifamily Residential [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	0	312	310
Commercial and Industrial [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	253,078	287,707	137,664
Total purchased Loans	56,693	68,825	46,183
Commercial and Industrial [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	15,608	20,340	10,766
Commercial and Industrial [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	20,960	23,048	14,526
Commercial and Industrial [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	4,539	4,900	5,138
Commercial and Industrial [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	7,042	10,659	2,648
Commercial and Industrial [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	23	22	0
Commercial and Industrial [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	8,059	9,297	12,975
Commercial and Industrial [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	462	559	130
Consumer [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	24,869	25,669	23,769
Total purchased Loans	11,965	15,268	6,700
Consumer [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	1,033	1,605	1,448
Consumer [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	316	272	204
Consumer [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	322	420	332
Consumer [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	9,959	12,538	4,065
Consumer [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	2	3	0
Consumer [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	329	426	647
Consumer [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	4	4	4
Direct Financing Leases [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	126,326	115,475	92,856
Other [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	89,552	93,996	91,577
Total purchased Loans	10,183	13,062	5,824
Other [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 33 [Member]
Loans And Leases [Line Items]
Total purchased Loans	4,623	4,845	1,204
Other [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 44 [Member]
Loans And Leases [Line Items]
Total purchased Loans	3,689	5,830	2,835
Other [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 55 [Member]
Loans And Leases [Line Items]
Total purchased Loans	310	597	529
Other [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 36 [Member]
Loans And Leases [Line Items]
Total purchased Loans	763	945	200
Other [Member] | Purchased Loans Without Evidence of Credit Deterioration at Acquisition [Member] | FV 77 [Member]
Loans And Leases [Line Items]
Total purchased Loans	0	0	0
Other [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 66 [Member]
Loans And Leases [Line Items]
Total purchased Loans	798	845	1,056
Other [Member] | Purchased Loans with Evidence of Credit Deterioration of Acquisition [Member] | FV 88 [Member]
Loans And Leases [Line Items]
Total purchased Loans	0	0	0
Satisfactory [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	3,709,854	3,393,686	2,304,430
Satisfactory [Member] | Real Estate [Member] | Residential 1-4 Family [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	293,140	271,576	244,259
Satisfactory [Member] | Real Estate [Member] | Non-Farm/Non-Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,356,456	1,300,582	954,057
Satisfactory [Member] | Real Estate [Member] | Construction/Land Development [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,433,497	1,190,005	613,474
Satisfactory [Member] | Real Estate [Member] | Agricultural [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	23,663	22,446	21,228
Satisfactory [Member] | Real Estate [Member] | Multifamily Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	187,966	171,806	164,062
Satisfactory [Member] | Commercial and Industrial [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	180,448	208,054	103,039
Satisfactory [Member] | Consumer [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	24,243	25,267	23,203
Satisfactory [Member] | Direct Financing Leases [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	125,845	114,586	91,927
Satisfactory [Member] | Other [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	84,596	89,364	89,181
Moderate [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	487,532	449,989	360,148
Moderate [Member] | Real Estate [Member] | Residential 1-4 Family [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	0	0	0
Moderate [Member] | Real Estate [Member] | Non-Farm/Non-Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	158,588	142,688	130,787
Moderate [Member] | Real Estate [Member] | Construction/Land Development [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	203,405	192,046	155,254
Moderate [Member] | Real Estate [Member] | Agricultural [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	13,974	12,375	9,914
Moderate [Member] | Real Estate [Member] | Multifamily Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	37,686	37,886	29,625
Moderate [Member] | Commercial and Industrial [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	68,809	59,967	31,434
Moderate [Member] | Consumer [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	0	0	0
Moderate [Member] | Direct Financing Leases [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	354	715	881
Moderate [Member] | Other [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	4,716	4,312	2,253
Watch [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	83,403	98,873	91,472
Watch [Member] | Real Estate [Member] | Residential 1-4 Family [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	4,456	4,082	2,449
Watch [Member] | Real Estate [Member] | Non-Farm/Non-Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	53,874	53,863	53,658
Watch [Member] | Real Estate [Member] | Construction/Land Development [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	11,049	11,135	23,254
Watch [Member] | Real Estate [Member] | Agricultural [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	9,293	10,226	9,747
Watch [Member] | Real Estate [Member] | Multifamily Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,663	713	389
Watch [Member] | Commercial and Industrial [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	2,403	18,310	1,642
Watch [Member] | Consumer [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	369	141	220
Watch [Member] | Direct Financing Leases [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	75	117	0
Watch [Member] | Other [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	221	286	113
Substandard [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	30,316	37,322	22,453
Substandard [Member] | Real Estate [Member] | Residential 1-4 Family [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	6,239	7,595	6,080
Substandard [Member] | Real Estate [Member] | Non-Farm/Non-Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	6,033	6,408	5,981
Substandard [Member] | Real Estate [Member] | Construction/Land Development [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	12,386	18,652	4,144
Substandard [Member] | Real Estate [Member] | Agricultural [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	2,254	2,188	3,019
Substandard [Member] | Real Estate [Member] | Multifamily Residential [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,658	751	1,256
Substandard [Member] | Commercial and Industrial [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	1,418	1,376	1,549
Substandard [Member] | Consumer [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	257	261	346
Substandard [Member] | Direct Financing Leases [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	52	57	48
Substandard [Member] | Other [Member]
Loans And Leases [Line Items]
Total non-purchased loans and leases	$19	$34	$30

Allowance_for_Loan_and_Lease_L7

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Schedule of Aging Analysis Past Due Loans and Leases, Loans Purchased and Non-Purchased by FDIC Loss Share Agreements (Detail) (USD $)	Mar. 31, 2015		Dec. 31, 2014		Mar. 31, 2014
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	$13,811		$15,104		$12,593
90 Days or More	11,998	[1]	16,381	[1]	8,119	[1]
Total Past Due	25,809		31,485		20,712
Current	4,285,296		3,948,385		2,757,791
Total non-purchased loans and leases	4,311,105		3,979,870		2,778,503
Total Purchased Loans	2,042,164		1,147,947		793,488
Purchased Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	23,288		20,006		24,940
90 Days or More	26,964		28,773		69,802
Total Past Due	50,252		48,779		94,742
Current	1,991,912		1,099,168		698,746
Total Purchased Loans	2,042,164		1,147,947		793,488
Real Estate [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total Purchased Loans	1,963,323		1,050,792		734,781
Real Estate [Member] | Residential 1-4 Family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	5,161		6,352		3,167
90 Days or More	1,618	[1]	1,536	[1]	2,108	[1]
Total Past Due	6,779		7,888		5,275
Current	297,056		275,365		247,513
Total non-purchased loans and leases	303,835		283,253		252,788
Total Purchased Loans	369,526		355,705		240,606
Real Estate [Member] | Non-Farm/Non-Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	4,276		2,708		647
90 Days or More	376	[1]	1,445	[1]	1,376	[1]
Total Past Due	4,652		4,153		2,023
Current	1,570,299		1,499,388		1,142,460
Total non-purchased loans and leases	1,574,951		1,503,541		1,144,483
Total Purchased Loans	1,285,827		504,889		352,884
Real Estate [Member] | Construction/Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	229		3,520		7,077
90 Days or More	9,414	[1]	12,881	[1]	3,950	[1]
Total Past Due	9,643		16,401		11,027
Current	1,650,694		1,395,437		785,099
Total non-purchased loans and leases	1,660,337		1,411,838		796,126
Total Purchased Loans	78,785		99,776		93,888
Real Estate [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,685		1,680		495
90 Days or More	305	[1]	304	[1]	582	[1]
Total Past Due	1,990		1,984		1,077
Current	47,194		45,251		42,831
Total non-purchased loans and leases	49,184		47,235		43,908
Total Purchased Loans	37,706		47,988		21,127
Real Estate [Member] | Multifamily Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	0		0		0
90 Days or More	0	[1]	0	[1]	0	[1]
Total Past Due	0		0		0
Current	228,973		211,156		195,332
Total non-purchased loans and leases	228,973		211,156		195,332
Total Purchased Loans	191,479		42,434		26,276
Real Estate [Member] | Purchased Loans [Member] | Residential 1-4 Family [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	7,783		8,088		11,457
90 Days or More	8,064		9,043		15,258
Total Past Due	15,847		17,131		26,715
Current	353,679		338,574		213,891
Total Purchased Loans	369,526		355,705		240,606
Real Estate [Member] | Purchased Loans [Member] | Non-Farm/Non-Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	6,919		8,907		9,160
90 Days or More	13,138		12,439		29,145
Total Past Due	20,057		21,346		38,305
Current	1,265,770		483,543		314,579
Total Purchased Loans	1,285,827		504,889		352,884
Real Estate [Member] | Purchased Loans [Member] | Construction/Land Development [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,623		1,197		1,979
90 Days or More	4,336		5,464		16,537
Total Past Due	5,959		6,661		18,516
Current	72,826		93,115		75,372
Total Purchased Loans	78,785		99,776		93,888
Real Estate [Member] | Purchased Loans [Member] | Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	249		237		1,129
90 Days or More	167		875		1,547
Total Past Due	416		1,112		2,676
Current	37,290		46,876		18,451
Total Purchased Loans	37,706		47,988		21,127
Real Estate [Member] | Purchased Loans [Member] | Multifamily Residential [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	5,375		515		0
90 Days or More	504		67		5,139
Total Past Due	5,879		582		5,139
Current	185,600		41,852		21,137
Total Purchased Loans	191,479		42,434		26,276
Commercial and Industrial [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,862		586		891
90 Days or More	198	[1]	94	[1]	16	[1]
Total Past Due	2,060		680		907
Current	251,018		287,027		136,757
Total non-purchased loans and leases	253,078		287,707		137,664
Total Purchased Loans	56,693		68,825		46,183
Commercial and Industrial [Member] | Purchased Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	1,090		863		1,028
90 Days or More	627		751		1,978
Total Past Due	1,717		1,614		3,006
Current	54,976		67,211		43,177
Total Purchased Loans	56,693		68,825		46,183
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	394		161		240
90 Days or More	27	[1]	55	[1]	78	[1]
Total Past Due	421		216		318
Current	24,448		25,453		23,451
Total non-purchased loans and leases	24,869		25,669		23,769
Total Purchased Loans	11,965		15,268		6,700
Consumer [Member] | Purchased Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	148		199		179
90 Days or More	98		103		179
Total Past Due	246		302		358
Current	11,719		14,966		6,342
Total Purchased Loans	11,965		15,268		6,700
Direct Financing Leases [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	41		39		59
90 Days or More	52	[1]	54	[1]	0	[1]
Total Past Due	93		93		59
Current	126,233		115,382		92,797
Total non-purchased loans and leases	126,326		115,475		92,856
Other [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	163		58		17
90 Days or More	8	[1]	12	[1]	9	[1]
Total Past Due	171		70		26
Current	89,381		93,926		91,551
Total non-purchased loans and leases	89,552		93,996		91,577
Total Purchased Loans	10,183		13,062		5,824
Other [Member] | Purchased Loans [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-89 Days Past Due	101		0		8
90 Days or More	30		31		19
Total Past Due	131		31		27
Current	10,052		13,031		5,797
Total Purchased Loans	$10,183		$13,062		$5,824
[1]	All loans and leases greater than 90 days past due were on nonaccrual status at March 31, 2015 and 2014 and December 31, 2014.

Allowance_for_Loan_and_Lease_L8

Allowance for Loan and Lease Losses ("ALLL") and Credit Quality Indicators - Schedule of Aging Analysis Past Due Loans and Leases, Loans Purchased and Non-Purchased by FDIC Loss Share Agreements (Parenthetical) (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
30-89 Days Past Due [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases on nonaccrual status	$0.60	$0.90	$0.60
Non Accrual Loans Current [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans and leases on nonaccrual status	$1.70	$0.40	$3

Income_Taxes_Types_of_Temporar

Income Taxes - Types of Temporary Differences Between Tax Basis of Assets and Liabilities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Income Tax Disclosure [Abstract]
Allowance for loan and lease losses	$20,625	$20,324	$16,842
Differences in amounts reflected in the financial statements and income tax basis of purchased loans not previously covered by FDIC loss share agreements	32,962	20,444	18,453
Differences in amounts reflected in the financial statements and income tax basis for deposits assumed in acquisitions	8,926	1,337	1,157
Stock-based compensation	3,807	3,268	1,415
Deferred compensation	2,069	1,991	1,888
Foreclosed assets	4,471	3,503	4,831
Deferred fees and costs on loans and leases	5,244	4,785	1,604
Investment securities AFS	0	0	600
Differences in amounts reflected in the financial statements and income tax basis of assets acquired and liabilities assumed in FDIC-assisted acquisitions	8,050	8,098	5,393
Acquired net operating losses	13,569	13,332	13,180
Other, net	1,958	2,568	2,130
Total gross deferred tax assets	101,681	79,650	67,493
Less valuation allowance	-474	-474	-474
Net deferred tax asset	101,207	79,176	67,019
Accelerated depreciation on premises and equipment	19,114	18,653	17,954
Investment securities AFS	7,675	7,692	0
Acquired intangible assets	10,935	9,743	5,066
Total gross deferred tax liabilities	37,724	36,088	23,020
Net deferred tax assets	$63,483	$43,088	$43,999

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Schedule Of Income Taxes [Line Items]
Deferred tax valuation allowance	474,000	$474,000	$474,000
Bancshares Inc [Member]
Schedule Of Income Taxes [Line Items]
Net operating losses carryforwards	15,700,000
Bancshares Inc [Member] | Minimum [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards expiration year	2030
Bancshares Inc [Member] | Maximum [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards expiration year	2034
Intervest Bancshares Corporation [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards subject to expiration	6,300,000
Intervest Bancshares Corporation [Member] | Minimum [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards expiration year	2030
Intervest Bancshares Corporation [Member] | Maximum [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards expiration year	2035
FNB Shelby [Member]
Schedule Of Income Taxes [Line Items]
Net operating losses carryforwards	20,000,000
FNB Shelby [Member] | Expiration Year 2032 [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards expiration year	2032
Operating loss carryforwards subject to expiration	12,500,000
FNB Shelby [Member] | Expiration Year 2033 [Member]
Schedule Of Income Taxes [Line Items]
Operating loss carryforwards expiration year	2033
Operating loss carryforwards subject to expiration	7,500,000

Supplemental_Data_for_Cash_Flo2

Supplemental Data for Cash Flows - Schedule of Supplemental Cash Flow Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Cash Flows [Abstract]
Interest	$6,773	$4,782
Taxes	2,029	772
Net change in unrealized gains/losses on investment securities AFS	44	11,325
Loans and premises and equipment transferred to foreclosed assets	6,746	2,205
Unsettled AFS investment security purchases	0	2,267
Common stock issued in merger and acquisition transaction	$238,476	$0

Guarantees_and_Commitments_Add

Guarantees and Commitments - Additional Information (Detail) (USD $)	Mar. 31, 2015
Guarantees And Commitments [Line Items]
Outstanding commitments to extend credit, excluding mortgage interest rate lock commitments	$3,410,000,000
Commitments To Extend Credit [Member]
Guarantees And Commitments [Line Items]
Maximum amount of future payments required to make under guarantees	13,700,000
Collateralized commitments	$13,500,000

Guarantees_and_Commitments_Con

Guarantees and Commitments - Contractual Maturities (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Fair Value Disclosures [Abstract]
2015	$168,610
2016	338,819
2017	1,746,740
2018	808,907
2019	92,812
Thereafter	253,563
Total	$3,409,451

Subordinated_Debentures_Schedu

Subordinated Debentures - Schedule of Issues of Trust Preferred Securities Outstanding and Subordinated Debentures Owed to Trust (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	$121,652
Unamortized Discount	-4,388
Carrying Value of Subordinated Debentures	117,264	64,950	64,950
Trust Preferred Securities of the Trusts	118,000
Ozark II [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	14,434
Unamortized Discount	0
Carrying Value of Subordinated Debentures	14,434
Trust Preferred Securities of the Trusts	14,000
Contractual Interest Rate	3.18%
Ozark III [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	14,433
Unamortized Discount	0
Carrying Value of Subordinated Debentures	14,433
Trust Preferred Securities of the Trusts	14,000
Contractual Interest Rate	3.20%
Ozark IV [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	15,464
Unamortized Discount	0
Carrying Value of Subordinated Debentures	15,464
Trust Preferred Securities of the Trusts	15,000
Contractual Interest Rate	2.48%
Ozark V [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	20,619
Unamortized Discount	0
Carrying Value of Subordinated Debentures	20,619
Trust Preferred Securities of the Trusts	20,000
Contractual Interest Rate	1.87%
Intervest II [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	15,464
Unamortized Discount	-701
Carrying Value of Subordinated Debentures	14,763
Trust Preferred Securities of the Trusts	15,000
Contractual Interest Rate	3.22%
Intervest III [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	15,464
Unamortized Discount	-811
Carrying Value of Subordinated Debentures	14,653
Trust Preferred Securities of the Trusts	15,000
Contractual Interest Rate	3.06%
Intervest IV [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	15,464
Unamortized Discount	-1,475
Carrying Value of Subordinated Debentures	13,989
Trust Preferred Securities of the Trusts	15,000
Contractual Interest Rate	2.67%
Intervest V [Member]
Subordinated Borrowing [Line Items]
Subordinated Debentures Owed to Trust	10,310
Unamortized Discount	-1,401
Carrying Value of Subordinated Debentures	8,909
Trust Preferred Securities of the Trusts	$10,000
Contractual Interest Rate	1.92%

Subordinated_Debentures_Additi

Subordinated Debentures - Additional Information (Detail) (USD $)	0 Months Ended	3 Months Ended
	Feb. 10, 2015	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Subordinated Borrowing [Line Items]
Subordinated debentures, outstanding		$121,652,000
Trust preferred securities, outstanding		118,000,000
Subordinated debentures, carrying value		117,264,000	64,950,000	64,950,000
Investment in the common equity issued by the trusts		3,700,000
Aggregate common equity		3,700,000		1,900,000
Intervest Trusts [Member]
Subordinated Borrowing [Line Items]
Subordinated debentures, outstanding	56,700,000
Trust preferred securities, outstanding	55,000,000
Subordinated debentures, estimated fair value	52,200,000
Trust common equity	1,700,000
Intervest Trusts [Member] | Subordinated Debentures [Member]
Subordinated Borrowing [Line Items]
Fair value adjustment, amortization period	8 years
Subordinated debentures, fair value adjustment	4,500,000
Intervest II [Member]
Subordinated Borrowing [Line Items]
Trust preferred securities, outstanding		15,000,000
LIBOR plus rate, percentage	2.95%
Interest rate, adjustable quarterly		90-day London Interbank Offered Rates ("LIBOR") plus 2.95%
Maturity date	17-Sep-33
Subordinated debentures, carrying value		14,763,000
Intervest III [Member]
Subordinated Borrowing [Line Items]
Trust preferred securities, outstanding		15,000,000
LIBOR plus rate, percentage	2.79%
Interest rate, adjustable quarterly		90-day LIBOR plus 2.79%
Maturity date	17-Mar-34
Subordinated debentures, carrying value		14,653,000
Intervest IV [Member]
Subordinated Borrowing [Line Items]
Trust preferred securities, outstanding		15,000,000
LIBOR plus rate, percentage	2.40%
Interest rate, adjustable quarterly		90-day LIBOR plus 2.40%
Maturity date	20-Sep-34
Subordinated debentures, carrying value		13,989,000
Intervest V [Member]
Subordinated Borrowing [Line Items]
Trust preferred securities, outstanding		10,000,000
LIBOR plus rate, percentage	1.65%
Interest rate, adjustable quarterly		90-day LIBOR plus 1.65%
Maturity date	15-Dec-36
Subordinated debentures, carrying value		$8,909,000
Debentures [Member]
Subordinated Borrowing [Line Items]
Interest payment terms		Period not to exceed five consecutive years

StockBased_Compensation_Additi

Stock-Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended
In Millions, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation arrangement by share-based payment award options exercisable intrinsic value per share	$0
Stock-based compensation expense for stock options included in non-interest expense	$0.60	$0.40
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total intrinsic value of options exercised during the period	1.4	3.9
Total unrecognized compensation expenses	4.3
Unrecognized compensation cost, weighted-average period, years	2 years 2 months 12 days
Stock options, granted	0	0
Restricted Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee options issued with a vesting period, years	3 years
Stock-based compensation expense for stock options included in non-interest expense	1.3	0.9
Total unrecognized compensation expenses	$10.80
Unrecognized compensation cost, weighted-average period, years	2 years 4 months 24 days
Nonqualified Stock Option Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee options issued with a vesting period, years	3 years
Employee options expire after issuance, years	7 years
Number of shares available to non-employee directors through the non qualified stock option plan for non-employee directors	2,000
Expiration period of options issued to non-employee director	10 years
Nonqualified Stock Option Plan [Member] | Director [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of shares available to non-employee directors through the non qualified stock option plan for non-employee directors	2,000

StockBased_Compensation_Summar

Stock-Based Compensation - Summary of Stock Option Activity (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015		Mar. 31, 2014
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Outstanding - January 1, 2015, Options	1,859,350
Granted, Options	0
Exercised, Options	-53,000		-176,600
Forfeited, Options	-57,900
Outstanding - March 31, 2015, Options	1,748,450
Fully vested and exercisable - March 31, 2015, Options	365,600
Expected to vest in future periods, Options	1,246,680
Fully vested and expected to vest - March 31, 2015, Options	1,612,280	[1]
Outstanding - January 1, 2015, Weighted-Average Exercise Price/Share	$23.49
Granted, Weighted-Average Exercise Price/Share	$0
Exercised, Weighted-Average Exercise Price/Share	$10.30
Forfeited, Weighted-Average Exercise Price/Share	$26.85
Outstanding - March 31, 2015, Weighted-Average Exercise Price/Share	$23.78
Fully vested and exercisable at March 31, 2015, Weighted-Average Exercise Price/Share	$13.55
Fully vested and expected to vest at March 31, 2015, Weighted-Average Exercise Price/Share	$23.13	[1]
Outstanding - March 31, 2015, Weighted-Average Remaining Contractual Life (in years)	5 years 4 months 24 days
Fully vested and exercisable at March 31, 2015, Weighted-Average Remaining Contractual Life (in years)	4 years 6 months
Fully vested and expected to vest at March 31, 2015, Weighted-Average Remaining Contractual Life (in years)	5 years 4 months 24 days
Outstanding - March 31, 2015, Aggregate Intrinsic Value	$22,990	[2]
Fully vested and exercisable at March 31, 2015, Aggregate Intrinsic Value	8,549	[2]
Fully vested and expected to vest at March 31, 2015, Aggregate Intrinsic Value	$22,254	[2]
[1]	At March 31, 2015, the Company estimated that outstanding options to purchase 136,170 shares of its common stock would not vest and would be forfeited prior to their vesting date.
[2]	Based on closing price of $36.93 per share on March 31, 2015.

StockBased_Compensation_Summar1

Stock-Based Compensation - Summary of Stock Option Activity (Parenthetical) (Detail) (USD $)	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Estimated number of common shares that could be forfeited before the vesting date	136,170
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Common stock, closing price, per share	36.93

StockBased_Compensation_Summar2

Stock-Based Compensation - Summary of Non-Vested Restricted Stock Activity (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015
Disclosure Of Compensation Related Costs Sharebased Payments Restricted Stock [Abstract]
Outstanding - January 1, 2015	444,700
Granted	243,300
Forfeited	-27,250
Vested	0
Outstanding - March 31, 2015	660,750
Weighted-average grant date fair value	$25.22

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities at fair value	$0	$0	$0
Fair value of private placement bonds	19,100,000
Third party pricing for private placement bonds	19,100,000
Lower of the matrix price or par value of private placement bonds	19,100,000
Impaired financing receivable recorded investment reduction to estimated fair value	3,900,000
Estimated fair value of impaired loans and leases	12,600,000
Partial charge-offs to reduce carrying value of impaired loans and leases to estimated fair value	3,500,000
Specific loan and lease allocations to reduce carrying value of impaired loans and leases to estimated fair value	400,000
Partial charge-offs	1,300,000
Provision for loans and lease losses to cover charge-offs	1,300,000
Impaired purchased loans	$14,100,000
Minimum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated cost to sell percentage	8.00%
Discount rate of other real estate	8.00%
Maximum [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated cost to sell percentage	10.00%
Discount rate of other real estate	9.50%

Fair_Value_Measurements_Assets

Fair Value Measurements - Assets and Liabilities at Fair Value (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	$784,275	$839,321	$687,661
Total investment securities AFS	773,832	825,096	673,174
Impaired non-purchased loans and leases	12,574	19,480	5,978
Impaired purchased loans	14,147	14,040	29,332
Foreclosed assets	32,094	37,775	60,869
Total assets at fair value	832,647	896,391	769,353
Obligations of State and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	512,207	573,209	452,748
U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	259,975	251,233	219,740
Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	622	654	686
CRA Qualified Investment Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	1,028
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investment securities AFS	1,028	0	0
Impaired non-purchased loans and leases	0	0	0
Impaired purchased loans	0	0	0
Foreclosed assets	0	0	0
Total assets at fair value	1,028	0	0
Level 1 [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	0	0	0
Level 1 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	0	0	0
Level 1 [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	0	0	0
Level 1 [Member] | CRA Qualified Investment Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	1,028
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investment securities AFS	753,737	805,695	654,627
Impaired non-purchased loans and leases	0	0	0
Impaired purchased loans	0	0	0
Foreclosed assets	0	0	0
Total assets at fair value	753,737	805,695	654,627
Level 2 [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	493,140	553,808	434,201
Level 2 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	259,975	251,233	219,740
Level 2 [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	622	654	686
Level 2 [Member] | CRA Qualified Investment Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	0
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total investment securities AFS	19,067	19,401	18,547
Impaired non-purchased loans and leases	12,574	19,480	5,978
Impaired purchased loans	14,147	14,040	29,332
Foreclosed assets	32,094	37,775	60,869
Total assets at fair value	77,882	90,696	114,726
Level 3 [Member] | Obligations of State and Political Subdivisions [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	19,067	19,401	18,547
Level 3 [Member] | U.S. Government Agency Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	0	0	0
Level 3 [Member] | Corporate Obligations [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	0	0	0
Level 3 [Member] | CRA Qualified Investment Fund [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment securities AFS	$0

Fair_Value_Measurements_Assets1

Fair Value Measurements - Assets and Liabilities at Fair Value (Parenthetical) (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Fair Value Disclosures [Abstract]
Investments carried at cost	$10.40	$14.20	$14.50

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Information Related to Level 3 Non-Recurring Fair Value Measurements (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Fair Value Measurements Disclosure [Line Items]
Impaired non-purchased loans and leases	$12,574	$19,480	$5,978
Impaired purchased loans	14,147	14,040	29,332
Foreclosed assets	32,094	37,775	60,869
Level 3 [Member]
Fair Value Measurements Disclosure [Line Items]
Impaired non-purchased loans and leases	12,574	19,480	5,978
Impaired purchased loans	14,147	14,040	29,332
Foreclosed assets	$32,094	$37,775	$60,869

Fair_Value_Measurements_Assets2

Fair Value Measurements - Assets Measured at Fair Value on Recurring Basis Utilizing Level 3 Inputs (Detail) (Investment Securities AFS [Member], USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Investment Securities AFS [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Beginning Balance, Asset	$19,401	$18,682
Total realized gains (losses) included in earnings	0	0
Total unrealized gains (losses) included in comprehensive income	-87	248
Paydowns and maturities	-247	-383
Sales	0	0
Transfers in and/or out of Level 3	0	0
Ending Balance, Asset	$19,067	$18,547

Fair_Value_of_Financial_Instru2

Fair Value of Financial Instruments - Additional Information (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Millions, unless otherwise specified
Fair Value Disclosures [Abstract]
Investments in bank stock	$10.40	$14.20	$14.50

Fair_Value_of_Financial_Instru3

Fair Value of Financial Instruments - Estimated Fair Values of Financial Instruments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities AFS	$784,275	$839,321	$687,661
Time deposits	2,152,689	1,457,939	830,318
Other borrowings	161,318	190,855	280,885
FDIC clawback payable	0	0	26,202
Carrying Amount [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	425,794	150,203	188,351
Demand, savings and interest bearing transaction deposits	4,563,972	4,038,443	3,085,886
Repurchase agreements with customers	76,960	65,578	51,140
Carrying Amount [Member] | Level 1, 2 and 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities AFS	784,725	839,321	687,661
Carrying Amount [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases, net of ALLL	6,299,122	5,074,899	3,528,130
FDIC loss share receivable	0	0	57,782
FDIC clawback payable	0	0	26,202
Carrying Amount [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Time deposits	2,152,689	1,457,939	830,318
Other borrowings	161,318	190,855	280,885
Subordinated debentures	117,264	64,950	64,950
Estimated Fair Value [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and cash equivalents	425,794	150,203	188,351
Demand, savings and interest bearing transaction deposits	4,563,972	4,038,443	3,085,886
Repurchase agreements with customers	76,960	65,578	51,140
Estimated Fair Value [Member] | Level 1, 2 and 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Investment securities AFS	784,725	839,321	687,661
Estimated Fair Value [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Loans and leases, net of ALLL	6,230,658	5,042,831	3,496,946
FDIC loss share receivable	0	0	57,722
FDIC clawback payable	0	0	26,202
Estimated Fair Value [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Time deposits	2,158,211	1,463,590	830,583
Other borrowings	172,180	203,493	317,186
Subordinated debentures	$71,442	$39,103	$32,767

Recovered_Sheet1

Changes in and Reclassifications from Accumulated Other Comprehensive Income ("AOCI") - Changes in Accumulated Other Comprehensive Income (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance of AOCI - unrealized gains and losses on investment securities AFS	$14,132
Unrealized gains and losses on investment securities AFS	2,914	11,330
Tax effect of unrealized gains and losses on investment securities AFS	-1,110	-4,444
Tax effect of amounts reclassified from AOCI	965	2
Total other comprehensive income	235	6,883
Ending balance of AOCI - unrealized gains and losses on investment securities AFS	14,367	3,211
Unrealized gains and losses on investment securities AFS [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance of AOCI - unrealized gains and losses on investment securities AFS	14,132	-3,672
Unrealized gains and losses on investment securities AFS	2,914	11,330
Tax effect of unrealized gains and losses on investment securities AFS	-1,110	-4,444
Amounts reclassified from AOCI	-2,534	-5
Tax effect of amounts reclassified from AOCI	965	2
Total other comprehensive income	235	6,883
Ending balance of AOCI - unrealized gains and losses on investment securities AFS	$14,367	$3,211

Other_Operating_Expenses_Summa

Other Operating Expenses - Summary of Other Operating Expenses (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other Income and Expenses [Abstract]
Salaries and employee benefits	$22,597	$17,689
Net occupancy and equipment	7,291	5,044
Other operating expenses:
Postage and supplies	915	770
Advertising and public relations	583	400
Telecommunication services	1,348	1,001
Professional and outside services	4,386	2,128
Software and data processing	749	6,024
Travel and meals	796	556
FDIC insurance	750	503
FDIC and state assessments	310	260
ATM expense	708	210
Loan collection and repossession expense	1,733	460
Writedowns of foreclosed and other assets	2,192	64
Amortization of intangibles	1,596	813
FHLB prepayment penalty	2,480	0
Other	1,750	1,532
Total non-interest expense	$50,184	$37,454

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	3 Months Ended	0 Months Ended
	Mar. 31, 2015	6-May-15
Subsequent Event [Line Items]
Number of days for calculation of average closing stock	10 days
Measurement period for determining the average closing stock price	Second business day prior to the closing date
Subsequent Event [Member]
Subsequent Event [Line Items]
Total transaction value		$64,700,000
Date of definitive agreement		6-May-15
Bank of Carolinas Corporation [Member]
Subsequent Event [Line Items]
Total assets of the respective target financial institution to be acquired	363,000,000
Total loans of the respective target financial institution to be acquired	279,000,000
Total deposits of the respective target financial institution to be acquired	314,000,000
Bank of Carolinas Corporation [Member] | North Carolina [Member]
Subsequent Event [Line Items]
Number of bank offices	8
Minimum [Member]
Subsequent Event [Line Items]
Average closing stock price	29.28
Maximum [Member]
Subsequent Event [Line Items]
Average closing stock price	48.8