National Commerce 10-Q 15 May 15 2015 Q1 Quarterly report Financial data

Document_and_Entity_Informatio

Document and Entity Information	3 Months Ended
	Mar. 31, 2015	14-May-15
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	NCOM
Entity Registrant Name	NATIONAL COMMERCE CORPORATION
Entity Central Index Key	1609951
Current Fiscal Year End Date	-19
Entity Filer Category	Smaller Reporting Company
Entity Common Stock, Shares Outstanding		9,438,541

Unaudited_Consolidated_Balance

Unaudited Consolidated Balance Sheets (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Assets
Cash and due from banks	$15,696	$14,236
Interest-bearing deposits with banks	134,211	109,199
Cash and cash equivalents	149,907	123,435
Investment securities held-to-maturity (fair value of $5,730 at March 31, 2015)	5,730
Investment securities available-for-sale	31,901	34,932
Other investments	5,844	5,421
Mortgage loans held-for-sale	13,804	9,329
Loans, net of unearned income	920,740	888,721
Less: allowance for loan losses	9,522	9,802
Loans, net	911,218	878,919
Premises and equipment, net	27,509	27,560
Accrued interest receivable	2,200	2,193
Bank owned life insurance	11,762	10,641
Other real estate	1,665	1,008
Deferred tax assets, net	11,472	11,444
Goodwill	28,914	28,834
Core deposit intangible, net	1,646	1,757
Other assets	3,095	2,953
Total assets	1,206,667	1,138,426
Deposits:
Noninterest-bearing demand	232,655	217,643
Interest-bearing demand	158,512	154,816
Savings and money market	403,568	392,394
Time	205,482	206,207
Total deposits	1,000,217	971,060
Federal Home Loan Bank advances	22,000	22,000
Accrued interest payable	496	431
Other liabilities	11,782	8,774
Total liabilities	1,034,495	1,002,265
Commitments:
Shareholders' equity:
Preferred stock, 250,000 shares authorized, no shares issued or outstanding
Common stock, at March 31, 2015, $0.01 par value, 30,000,000 shares authorized and 9,438,541 shares issued and outstanding; at December 31, 2014, $0.01 par value, 12,500,000 shares authorized and 7,541,541 shares issued and outstanding	94	75
Additional paid-in capital	165,561	131,455
Accumulated deficit	-1,532	-3,453
Accumulated other comprehensive income	883	845
Total shareholders' equity attributable to National Commerce Corporation	165,006	128,922
Noncontrolling interest	7,166	7,239
Total shareholders' equity	172,172	136,161
Total liabilities and shareholders' equity	$1,206,667	$1,138,426

Unaudited_Consolidated_Balance1

Unaudited Consolidated Balance Sheets (Parenthetical) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, except Share data, unless otherwise specified
Statement of Financial Position [Abstract]
Held-to-Maturity Securities, Fair Value	$5,730
Preferred stock, shares authorized	250,000	250,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value	$0.01	$0.01
Common stock, shares authorized	30,000,000	12,500,000
Common stock, shares issued	9,438,541	7,541,541
Common stock, shares outstanding	9,438,541	7,541,541

Unaudited_Consolidated_Stateme

Unaudited Consolidated Statements of Earnings (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest and dividend income:
Interest and fees on loans	$11,792	$5,786
Interest and dividends on taxable investment securities	256	317
Interest on non-taxable investment securities	42	42
Interest on interest-bearing deposits and federal funds sold	103	63
Total interest income	12,193	6,208
Interest expense:
Interest on deposits	918	550
Interest on borrowings	109	109
Total interest expense	1,027	659
Net interest income	11,166	5,549
Provision for loan losses	161
Net interest income after provision for loan losses	11,005	5,549
Other income:
Service charges and fees on deposit accounts	267	166
Mortgage origination and fee income	1,271	705
Income from bank owned life insurance	79	60
Wealth management fees	19	14
(Loss) gain on other real estate	-13	5
Other	141	17
Total other income	1,764	967
Other expense:
Salaries and employee benefits	4,987	2,996
Commission-based compensation	796	306
Occupancy and equipment	836	436
Other	2,560	1,143
Total other expense	9,290	4,881
Earnings before income taxes	3,479	1,635
Income tax expense	1,092	592
Net earnings	2,387	1,043
Less: Net earnings attributable to noncontrolling interest	466
Net earnings attributable to National Commerce Corporation	1,921	1,043
Basic earnings per common share	$0.25	$0.18
Diluted earnings per common share	$0.25	$0.18
Core Deposits [Member]
Other expense:
Core deposit intangible amortization	$111

Unaudited_Consolidated_Stateme1

Unaudited Consolidated Statements of Comprehensive Income (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net earnings	$1,921	$1,043
Unrealized gains on investment securities available-for-sale:
Unrealized gains arising during the period, net of tax of $20 and $99 respectively	38	184
Other comprehensive income	38	184
Comprehensive income	$1,959	$1,227

Unaudited_Consolidated_Stateme2

Unaudited Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Unrealized gains arising during the period, tax	$20	$99

Unaudited_Consolidated_Stateme3

Unaudited Consolidated Statements of Changes in Shareholders' Equity (USD $)	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Accumulated Other Comprehensive Income [Member]	Noncontrolling Interest [Member]
In Thousands
Beginning balance, amount at Dec. 31, 2014	$136,161	$75	$131,455	($3,453)	$845	$7,239
Share-based compensation expense	234		234
Net earnings attributable to National Commerce Corporation	1,921			1,921
Sale of common stock, net of offering expenses of $604	33,891	19	33,872
Net earnings attributable to noncontrolling interest	466					466
Distributions paid to noncontrolling interest	-539					-539
Change in unrealized gain/loss on securities available-for- sale, net of tax	38				38
Ending balance, amount at Mar. 31, 2015	$172,172	$94	$165,561	($1,532)	$883	$7,166

Unaudited_Consolidated_Stateme4

Unaudited Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Common stock, offering expense	$604
Common Stock [Member]
Common stock, offering expense	604
Additional Paid-in Capital [Member]
Common stock, offering expense	$604

Unaudited_Consolidated_Stateme5

Unaudited Consolidated Statements of Cash Flows (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Cash flows from operating activities:
Net earnings	$1,921	$1,043
Adjustments to reconcile net earnings to net cash used by operating activities:
Provision for loan losses	161
Net earnings attributable to noncontrolling interest	466
Depreciation, amortization and accretion	571	207
Loss on ineffective portion of fair value hedge derivative	23	37
Change in mortgage loan derivative	-181	-33
Loss on trade or sale of premises and equipment	5
Share-based compensation expense	234	107
Income from bank owned life insurance	-79	-60
Loss (gain) on other real estate	13	-5
Change in:
Mortgage loans held-for-sale	-4,475	-3,143
Other assets and accrued interest receivable	24	-74
Other liabilities and accrued interest payable	-1,902	-300
Net cash used by operating activities	-3,219	-2,221
Cash flows from investing activities:
Proceeds from calls, maturities and paydowns of securities available-for-sale	5,577	1,297
Purchases of securities available-for-sale	-2,500
Purchases of securities held-to-maturity	-1,046
Proceeds from sale of other investments	703	117
Purchases of other investments	-1,126
Net change in loans	-33,111	24,874
Proceeds from sale of other real estate	10	5
Investment in bank owned life insurance	-1,042
Proceeds from the sale of premises and equipment	49
Purchases of premises and equipment	-332	-1,008
Net cash (used) provided by investing activities	-32,818	25,285
Cash flows from financing activities:
Net change in deposits	29,157	-41,809
Cash distribution paid to noncontrolling interests	-539
Proceeds from stock offering	34,495
Stock offering expenses	-604
Proceeds from exercise of options and warrants		15
Net cash provided (used) by financing activities	62,509	-41,794
Net change in cash and cash equivalents	26,472	-18,730
Cash and cash equivalents at beginning of the period	123,435	124,136
Cash and cash equivalents at end of the period	149,907	105,406
Cash paid during the period for:
Interest	962	700
Income taxes	15
Non-cash investing and financing activities:
Change in unrealized gain on securities available-for-sale, net of tax	-38	-184
Transfer of loans to other real estate	$694

Basis_of_Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Presentation	Note 1 – Basis of Presentation
	General
	The unaudited consolidated financial statements include the accounts of National Commerce Corporation (the “Company”), its wholly-owned subsidiary, National Bank of Commerce (the “Bank”), and its majority-owned subsidiary, CBI Holding Company, LLC (“CBI”). The Bank provides a full range of commercial and consumer banking services throughout Alabama, including metropolitan Birmingham, Huntsville, Lee County and Baldwin County. In addition to its Alabama locations, the Bank operates full-service banking offices in the greater Orlando area and in Vero Beach, Florida. The Bank is primarily regulated by the Office of the Comptroller of the Currency (“OCC”) and undergoes periodic examinations by this regulatory agency. The Company is regulated by the Federal Reserve and is also subject to periodic examinations. CBI is a transaction–based finance company headquartered in Decatur, Alabama that provides factoring, invoicing, collection and accounts receivable management services to transportation companies and automotive parts and service providers nationwide.
	In the opinion of management, the accompanying unaudited consolidated financial statements contain all adjustments necessary to present fairly National Commerce Corporation’s consolidated balance sheets, statements of earnings, comprehensive income, changes in stockholders’ equity and cash flows for the periods presented, and all such adjustments are of a normal recurring nature. All material intercompany transactions have been eliminated. The results of operations for the interim periods are not necessarily indicative of the results to be expected for the entire year.
	These interim consolidated financial statements have been prepared according to the rules and regulations of the Securities and Exchange Commission and, therefore, certain information and footnote disclosures normally presented in accordance with accounting principles generally accepted in the United States of America (“U.S. GAAP”) have been omitted or abbreviated. These financial statements should be read in conjunction with the Company’s audited consolidated financial statements and footnotes as of December 31, 2014, which are contained in the Company’s Annual Report on Form 10-K for the year ended December 31, 2014.
	Preparation of financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying disclosures. These estimates are based on management’s best knowledge of current events and actions that the Company may undertake in the future. Estimates are used in accounting for, among other items, the allowance for loan losses, useful lives for depreciation and amortization, fair value of financial instruments, deferred taxes and contingencies. Estimates that are particularly susceptible to significant change for the Company include the determination of the allowance for loan losses and the assessment of deferred tax assets and liabilities, and therefore are critical accounting estimates. Management does not anticipate any material changes to estimates in the near term. Factors that may cause sensitivity to the aforementioned estimates include, but are not limited to: external market factors, such as market interest rates and employment rates; changes to operating policies and procedures; economic conditions in our markets; and changes in applicable banking regulations. Actual results may ultimately differ from estimates, although management does not generally believe that such differences would materially affect the consolidated financial statements in any individual reporting period presented.

Reclassifications_and_Reincorp

Reclassifications and Reincorporation	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Reclassifications and Reincorporation	Note 2 – Reclassifications and Reincorporation
	Certain prior period amounts have been reclassified to conform to the presentation used in 2015. These reclassifications had no material effect on the operations, financial condition or cash flows of the Company.

Net_Earnings_per_Common_Share

Net Earnings per Common Share	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Net Earnings per Common Share	Note 3 – Net Earnings per Common Share
	Basic earnings per common share are computed by dividing net income by the weighted-average number of shares of common stock outstanding during the period. Diluted earnings per common share are computed by dividing net income by the effect of the issuance of potential common shares that are dilutive and by the sum of the weighted-average number of shares of common stock outstanding. Anti-dilutive potential common shares (options and warrants) are excluded from the diluted earnings per share computation and totaled 102,297 and 30,000 for the three months ended March 31, 2015 and 2014, respectively.
	The reconciliation of the components of the basic and diluted earnings per share is as follows.
		For the Three Months Ended
		March 31,
		2015		2014
	Net earnings available to common shareholders	$	1,921		1,043
	Weighted average common shares outstanding		7,701,663		5,730,780
	Dilutive effect of stock options		33,078		9,859
	Dilutive effect of directors’ shares		3,147		—
	Dilutive effect of performance share awards		63,689		35,161
	Diluted common shares		7,801,577		5,775,800
	Basic earnings per common share		0.25		0.18
	Diluted earnings per common share	$	0.25		0.18

Securities

Securities	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Securities	Note 4 – Securities
	The amortized cost and fair value of held-to-maturity and available-for-sale debt securities at March 31, 2015 and December 31, 2014 were as follows.
		Held-to-Maturity Securities
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
	March 31, 2015	Cost		Gains		Losses		Value
	Municipal securities	$	5,730		—		—		5,730
		$	5,730		—		—		5,730
		Available-for-Sale Securities
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
	March 31, 2015	Cost		Gains		Losses		Value
	Mortgage-backed securities	$	26,135		1,155		58		27,232
	Municipal securities		4,408		273		12		4,669
		$	30,543		1,428		70		31,901
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
	December 31, 2014	Cost		Gains		Losses		Value
	U.S. Treasury securities	$	1,501		—		—		1,501
	Mortgage-backed securities		27,723		1,138		111		28,750
	Municipal securities		4,408		279		6		4,681
		$	33,632		1,417		117		34,932
	Management evaluates securities for other-than-temporary impairment on a quarterly basis, and more frequently when economic or market concerns warrant such evaluation. Consideration is given to (1) the length of time and the extent to which the fair value has been less than cost, (2) the financial condition and near-term prospects of the issuer and (3) the intent and ability of the Company to retain its investment in the issuer for a period of time sufficient to allow for any anticipated recovery in fair value.
	Details concerning the Company’s available-for-sale debt securities with unrealized losses as of March 31, 2015 and December 31, 2014 are as follows.
		Available-for-Sale Securities
		31-Mar-15
		Less than 12 Months				12 Months or More				Total
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	Mortgage-backed securities	$	—		—		7,142		58		7,142		58
	Municipal securities		—		—		488		12		488		12
		$	—		—		7,630		70		7,630		70
		31-Dec-14
		Less than 12 Months				12 Months or More				Total
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	U.S. Treasury securities	$	—		—		—		—		—		—
	Mortgage-backed securities		—		—		7,705		111		7,705		111
	Municipal securities		—		—		494		6		494		6
		$	—		—		8,199		117		8,199		117
	As of March 31, 2015, the Company did not consider securities with unrealized losses to be other-than-temporarily impaired. The unrealized losses in each category have occurred as a result of changes in interest rates, market spreads and market conditions subsequent to purchase. The Company has the ability and intent to hold its securities for a period of time sufficient to allow for a recovery in fair value. There were no other-than-temporary impairments charged to earnings during the three month periods ended March 31, 2015 and 2014.
	During the three month periods ended March 31, 2015 and 2014, the Company did not sell any debt securities.
	The amortized cost and estimated fair value of debt securities at March 31, 2015, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers have the right to call or prepay obligations with or without call or prepayment penalties.
		Available-for-Sale Securities				Held-to-Maturity Securities
		Amortized		Fair		Amortized		Fair
		Cost		Value		Cost		Value
	Municipal securities:
	0 to 5 years	$	—		—	$	—		—
	5 to 10 years		1,047		1,107		—		—
	Over 10 years		3,361		3,562		5,730		5,730
	Mortgage-backed securities		26,135		27,232		—		—
		$	30,543		31,901	$	5,730		5,730

Loans_Allowance_for_Loan_Losse

Loans, Allowance for Loan Losses and Credit Quality	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Loans, Allowance for Loan Losses and Credit Quality	Note 5 – Loans, Allowance for Loan Losses and Credit Quality
	Major classifications of loans at March 31, 2015 and December 31, 2014 are summarized as follows.
		March 31, 2015			December 31, 2014
	Commercial, financial and agricultural	$	141,209			131,657
	Factored commercial receivables		69,541			82,600
	Real estate - mortgage		604,056			577,268
	Real estate - construction		90,263			83,663
	Consumer		16,217			13,962
			921,286			889,150
	Less: Unearned fees		546			429
	Total loans and leases		920,740			888,721
	Allowance for loan losses		(9,522	)		(9,802	)
	Total net loans and leases	$	911,218			878,919
	The Company grants loans and extensions of credit to individuals and a variety of businesses and corporations located in its general trade areas throughout Alabama and Florida, including metropolitan Birmingham, Huntsville, Lee County and Baldwin County in Alabama and metropolitan Orlando and Vero Beach in Florida. Through CBI, the Company also purchases receivables from transportation companies and automotive parts and service providers nationwide. Although the Company has a diversified loan portfolio, a substantial portion of the loan portfolio is collateralized by improved and unimproved real estate and is dependent upon the real estate market. Portfolio segments utilized by the Company are identified below. Relevant risk characteristics for these portfolio segments generally include debt service coverage, loan-to-value ratios and financial performance on non-consumer loans and credit scores, debt-to-income, collateral type and loan-to-value ratios for consumer loans.
	The following table presents the balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method for the periods indicated. The acquired loans are not included in the allowance for loan losses calculation, as these loans are recorded at fair value, and there has been no further indication of credit deterioration that would require an additional provision.
		Commercial,			Factored
		financial and			commercial			Real estate -			Real estate -
	Balance, March 31, 2015	agricultural			receivables			mortgage			construction			Consumer			Unallocated			Total
	Balance, December 31, 2014	$	1,523			955			5,047			647			562			1,068			9,802
	Provisions charged to operating expense		(43	)		161			453			122			(245	)		(287	)		161
	Loans charged off		(1	)		(566	)		(332	)		—			—			—			(899	)
	Recoveries		20			406			24			8			—			—			458
	Balance, March 31, 2015	$	1,499			956			5,192			777			317			781			9,522
	Ending balance, individually evaluated for impairment	$	—			678						100			—			—			778
	Ending balance, collectively evaluated for impairment	$	1,499			278			5,192			677			317			781			8,744
	Loans:
	Individually evaluated for impairment	$	—			820			430			187			—			—			1,437
	Collectively evaluated for impairment	$	140,226			68,721			596,432			89,733			15,885			—			910,997
	Acquired loans with deteriorated credit quality	$	983			—			7,194			343			332			—			8,852
		Commercial,			Factored
		financial and			commercial			Real estate -			Real estate -
	Balance, March 31, 2014	agricultural			receivables			mortgage			construction			Consumer			Unallocated			Total
	Balance, December 31, 2013	$	1,398			—			4,449			964			243			2,065			9,119
	Provisions charged to operating expense		(98	)		—			159			(359	)		(192	)		490			—
	Loans charged off		—			—			—			—			(1	)		—			(1	)
	Recoveries		16			—			13			13			2			—			44
	Balance, March 31, 2014	$	1,316			—			4,621			618			52			2,555			9,162
	Ending balance, individually evaluated for impairment	$	—			—			—			—			—			—			—
	Ending balance, collectively evaluated for impairment	$	1,316			—			4,621			618			52			2,555			9,162
	Loans:
	Individually evaluated for impairment	$	92			—			3,225			—			—			—			3,317
	Collectively evaluated for impairment	$	84,958			—			407,807			55,576			6,110			—			554,451
	The Company individually evaluates for impairment all loans that are on nonaccrual status. Additionally, all troubled debt restructurings are individually evaluated for impairment. A loan is considered impaired when, based on current events and circumstances, it is probable that all amounts due according to the contractual terms of the loan will not be collected. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, at the loan’s observable market price or at the fair value of the collateral if the loan is collateral dependent. Management may also elect to apply an additional collective reserve to groups of impaired loans based on current economic or market factors. Interest payments received on impaired loans are generally applied as a reduction of the outstanding principal balance. During the three months ended March 31, 2015 and 2014, the Company did not modify any loans that would be considered a troubled debt restructuring.
	The following tables present impaired loans by class of loans as of March 31, 2015 and December 31, 2014. The purchased credit impaired loans are not included in these tables because they are carried at fair value and accordingly have no related associated allowance.
					Unpaid						Average
		Recorded			Principal			Related			Recorded
	March 31, 2015	Investment			Balance			Allowance			Investment
	Impaired loans without related allowance:
	Commercial, financial and agricultural	$	—			151			—			—
	Factored commercial receivables		—			—			—			—
	Real estate - mortgage		2,921			4,805			—			1,987
	Real estate - construction		—			—			—			—
	Consumer		86			176			—			43
	Total	$	3,007			5,132			—			2,030
	Impaired loans with related allowance:
	Commercial, financial and agricultural	$	—			—			—			—
	Factored commercial receivables		820			820			678			1,213
	Real estate - mortgage		—			—			—			513
	Real estate - construction		187			187			100			193
	Consumer		—			—			—			—
	Total	$	1,007			1,007			778			1,919
	Total impaired loans:
	Commercial, financial and agricultural	$	—			151			—			—
	Factored commercial receivables		820			820			678			1,213
Real estate - mortgage		2,921			4,805			—			2,500
Real estate - construction		187			187			100			193
Consumer		86			176			—			43
Total	$	4,014			6,139			778			3,949
				Unpaid						Average
	Recorded			Principal			Related			Recorded
December 31, 2014	Investment			Balance			Allowance			Investment
Impaired loans without related allowance:
Commercial, financial and agricultural	$	—			—			—			24
Factored commercial receivables		—			—			—			—
Real estate - mortgage		1,052			2,030			—			1,770
Real estate - construction		—			—			—			—
Consumer		—			—			—			—
Total	$	1,052			2,030			—			1,794
Impaired loans with related allowance:
Commercial, financial and agricultural	$	—			—			—			—
Factored commercial receivables		1,605			1,605			473			321
Real estate - mortgage		1,026			1,026			350			205
Real estate - construction		198			198			50			40
Consumer		—			—			—			—
Total	$	2,829			2,829			873			566
Total impaired loans:
Commercial, financial and agricultural	$	—			—			—			24
Factored commercial receivables		1,605			1,605			473			321
Real estate - mortgage		2,078			3,056			350			1,975
Real estate - construction		198			198			50			40
Consumer		—			—			—			—
Total	$	3,881			4,859			873			2,360
For the three months ended March 31, 2015 and 2014, the Company did not recognize a material amount of interest income on impaired loans.
The following tables present the aging of the recorded investment in past due loans and non-accrual loan balances as of March 31, 2015 and December 31, 2014, by class of loans. All loans greater than 90 days past due are placed on non-accrual status, excluding factored receivables. For CBI’s factored receivables, which are commercial trade credit rather than promissory notes, the Company’s practice is to charge off unpaid recourse receivables when they become 90 days past due from the invoice due date and the non-recourse receivables at 120 days past due from the statement billing date. For the recourse receivables, the invoice is charged against the client reserve account established for such purposes, unless the client reserve is insufficient, at which point it is charged against the allowance for loan losses.
	30-59 Days			60-89 Days			> 90 Days			Total
March 31, 2015	Past Due			Past Due			Past Due			Past Due			Current			Total			Non-accrual
Commercial, financial and agricultural	$	—			—			—			—			141,209			141,209			—
Factored commercial receivables		4,415			676			168			5,259			64,282			69,541			—
Real estate - mortgage		345			—			866			1,211			602,845			604,056			2,921
Real estate - construction		—			—			—			—			90,263			90,263			187
Consumer		171			35			82			288			15,929			16,217			86
Total	$	4,931			711			1,116			6,758			914,528			921,286			3,194
	30-59 Days			60-89 Days			> 90 Days			Total
December 31, 2014	Past Due			Past Due			Past Due			Past Due			Current			Total			Non-accrual
Commercial, financial and agricultural	$	—			—			—			—			131,657			131,657			—
Factored commercial receivables		6,327			1,013			217			7,557			75,043			82,600			—
Real estate - mortgage		191			1,963			1,572			3,726			573,542			577,268			4,133
Real estate - construction		198			—			—			198			83,465			83,663			676
Consumer		188			—			132			320			13,642			13,962			56
Total	$	6,904			2,976			1,921			11,801			877,349			889,150			4,865
The Company categorizes loans into risk categories based on relevant information about the ability of borrowers to service their debt such as: current financial information, historical payment experience, credit documentation, public information and current economic trends, among other factors. The Company analyzes loans individually by classifying the loans as to credit risk. This analysis is performed on a continuous basis. The Bank uses the following definitions for its risk ratings:
Other Assets Especially Mentioned (“OAEM”). Weakness exists that could cause future impairment, including the deterioration of financial ratios, past due status and questionable management capabilities. Collateral values generally afford adequate coverage but may not be immediately marketable.
Substandard. Specific and well-defined weaknesses exist that may include poor liquidity and deterioration of financial ratios. The loan may be past due and related deposit accounts experiencing overdrafts. Immediate corrective action is necessary.
Doubtful. Specific weaknesses characterized as Substandard that are severe enough to make collection in full unlikely. There is no reliable secondary source of full repayment. Loans classified as Doubtful will be placed on non-accrual, analyzed and fully or partially charged-off based on review of collateral and other relevant factors.
Loss. Specific weaknesses characterized as Doubtful that are severe enough to be considered uncollectible and of such minimal value that its continuance as an asset is not warranted.
Loans not meeting the criteria above that are analyzed individually as part of the above-described process are considered to be Pass rated loans. As of March 31, 2015 and December 31, 2014, and based on the most recent analysis performed, the risk category of loans by class of loans was as follows.
March 31, 2015	Pass			OAEM			Substandard			Doubtful			Total
Commercial, financial and agricultural	$	138,689			800			1,720						141,209
Factored commercial receivables		68,721			—			—			820			69,541
Real estate - mortgage		593,247			4,525			3,363			2,921			604,056
Real estate - construction		89,733			92			251			187			90,263
Consumer		15,423			202			506			86			16,217
Total	$	905,813			5,619			5,840			4,014			921,286
December 31, 2014	Pass			OAEM			Substandard			Doubtful			Total
Commercial, financial and agricultural	$	129,314			1,159			1,184			—			131,657
Factored commercial receivables		80,995			—			—			1,605			82,600
Real estate - mortgage		565,992			4,057			2,803			4,416			577,268
Real estate - construction		82,552			94			254			763			83,663
Consumer		13,192			201			477			92			13,962
Total	$	872,045			5,511			4,718			6,876			889,150

Fair_Value_Measurements_and_Di

Fair Value Measurements and Disclosures	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value Measurements and Disclosures	Note 6 – Fair Value Measurements and Disclosures
	The Company utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. Securities available-for-sale and derivative financial instruments are recorded at fair value on a recurring basis. Additionally, from time to time, the Company may be required to record at fair value other assets on a nonrecurring basis, such as impaired loans and other real estate and repossessed assets. These nonrecurring fair value adjustments typically involve application of the lower of cost or market accounting or write-downs of individual assets.
	Fair Value Hierarchy
	The Company groups assets and liabilities at fair value in three levels, based on the markets in which the assets and liabilities are traded and the reliability of the assumptions used to determine fair value. These levels are:
	Level 1 – Valuation is based upon quoted prices for identical instruments traded in active markets.
	Level 2 – Valuation is based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market.
	Level 3 – Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models and similar techniques.
	Following is a description of valuation methodologies used for assets and liabilities recorded or disclosed at fair value.
	Cash and Cash Equivalents
	For disclosure purposes, for cash, due from banks, interest-bearing deposits and federal funds sold, the carrying amount is a reasonable estimate of fair value.
	Securities Available-for-Sale
	Securities available-for-sale are recorded at fair value on a recurring basis. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are measured using independent pricing models or other model-based valuation techniques such as the present value of future cash flows, adjusted for the security’s credit rating, prepayment assumptions and other factors such as credit loss assumptions. Level 1 securities include those traded on an active exchange, such as the New York Stock Exchange or Nasdaq, and U.S. Treasury securities that are traded by dealers or brokers in active over-the-counter market funds. Level 2 securities include mortgage-backed securities issued by government sponsored enterprises and municipal bonds. Securities classified as Level 3 include asset-backed securities in less liquid markets.
	Securities Held-to-Maturity
	The fair value of securities held-to-maturity is estimated using the same measurement techniques as securities available-for-sale.
	Other Investments
	For disclosure purposes, the carrying amount of other investments approximates their fair value.
	Loans and Mortgage Loans Held-for-Sale
	The Company does not record loans at fair value on a recurring basis. However, from time to time, a loan is considered impaired and an allowance for loan losses is established. Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired. Once a loan is identified as individually impaired, management measures impairment using one of three methods, including collateral value, market value of similar debt and discounted cash flows. Those impaired loans not requiring an allowance represent loans for which the fair value of the expected repayments or collateral exceed the recorded investments in such loans. At March 31, 2015 and December 31, 2014, impaired loans were evaluated based on the fair value of the collateral. Impaired loans where an allowance is established based on the fair value of collateral, or loans that are charged down according to the fair value of collateral, require classification in the fair value hierarchy. When the fair value of the collateral is based on an observable market price, the Company records the impaired loan as nonrecurring Level 2. When the fair value is based on an appraised value, the Company records the impaired loan as nonrecurring Level 3.
	For disclosure purposes, the fair value of fixed rate loans is estimated by discounting the future cash flows using the current rates at which similar loans would be made to borrowers with similar credit ratings. For variable rate loans, the carrying amount is a reasonable estimate of fair value. Mortgage loans held-for-sale are carried at cost which is a reasonable estimate of fair value.
	Bank Owned Life Insurance
	For disclosure purposes, the fair value of the cash surrender value of life insurance policies is equivalent to the carrying value.
	Other Real Estate
	Other real estate properties are adjusted to fair value upon transfer of the loans to other real estate. Subsequently, other real estate assets are carried at the lower of carrying value or fair value. Fair value is based upon independent market prices, appraised values of the collateral or management’s estimation of the value of the collateral. When the fair value of the collateral is based on an observable market price, the Company records the other real estate as nonrecurring Level 2. When fair value is based on an appraised value or management’s estimate of value, the Company records the other real estate or repossessed asset as nonrecurring Level 3.
	Deposits
	For disclosure purposes, the fair value of demand deposits, NOW and money market accounts and savings accounts is the amount payable on demand at the reporting date. The fair value of fixed rate maturity certificates of deposit is estimated by discounting the future cash flows using the rates currently offered for deposits of similar remaining maturities.
	Federal Home Loan Bank Advances
	For disclosure purposes, the fair value of the Federal Home Loan Bank Advances is based on the quoted value for similar remaining maturities provided by the FHLB.
	Derivative Financial Instruments
	Derivative financial instruments are recorded at fair value on a recurring basis. The valuation of the Company’s derivative financial instruments is determined using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of the derivative. This analysis reflects the contractual terms of the derivative, including the period to maturity, and uses observable market-based inputs, including interest rate curves and implied volatilities. The fair value of the interest rate swaps are determined using the market standard methodology of netting the discounted future fixed cash receipts and the discounted expected variable cash payments. The variable cash payments are based on an expectation of future interest rates (forward curves derived from observable market interest rate curves).
	The Company incorporates credit valuation adjustments to appropriately reflect both its own nonperformance risk and the respective counterparty’s nonperformance risk in the fair value measurements. In adjusting the fair value of its derivative contracts for the effect of nonperformance risk, the Company has considered the impact of netting any applicable credit enhancements, such as collateral postings, thresholds, mutual puts and guarantees.
	Although the Company has determined that the majority of the inputs used to value its derivatives fall within Level 2 of the fair value hierarchy, the credit valuation adjustments associated with its derivatives utilize Level 3 inputs, such as estimates of current credit spreads, to evaluate the likelihood of default by itself or the counterparty. However, as of March 31, 2015 and December 31, 2014, the Company has assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions and has determined that the credit valuation adjustment is not significant to the overall valuation of its derivatives. As a result, the Company has determined that its derivative valuations are classified in Level 2 of the fair value hierarchy.
	Commitments to Extend Credit and Standby Letters of Credit
	Because commitments to extend credit and standby letters of credit are generally short-term and made using variable rates, the carrying value and estimated fair value associated with these instruments are immaterial.
	Assets and Liabilities Recorded at Fair Value on a Recurring Basis
	The table below presents the recorded amount of assets and liabilities measured at fair value on a recurring basis as of March 31, 2015 and December 31, 2014.
	March 31, 2015	Level 1		Level 2		Level 3		Total
	Mortgage-backed securities	$	—		27,232		—		27,232
	Municipal securities		—		4,669		—		4,669
	Total investment securities available-for-sale	$	—		31,901		—		31,901
	Derivative assets	$	—		418		—		418
	Derivative liabilities	$	—		716		—		716
	December 31, 2014	Level 1		Level 2		Level 3		Total
	U.S. Treasury securities	$	1,501		—		—		1,501
	Mortgage-backed securities		—		28,750		—		28,750
	Municipal securities		—		4,681		—		4,681
	Investment in mutual fund		—		—		—		—
	Total investment securities available-for-sale	$	1,501		33,431		—		34,932
	Derivative assets	$	—		105		—		105
	Derivative liabilities	$	—		425		—		425
	Assets and Liabilities Recorded at Fair Value on a Nonrecurring Basis
	The Company may be required, from time to time, to measure certain assets at fair value on a nonrecurring basis in accordance with U.S. GAAP. These include assets that are measured at the lower of cost or market that were recognized at fair value below cost at the end of the period. Assets measured at fair value on a nonrecurring basis are included in the table below as of March 31, 2015 and December 31, 2014.
	March 31, 2015	Level 1		Level 2		Level 3		Total
	Other real estate and repossessed assets	$	—		—		2,036		2,036
	Impaired loans		—		—		3,194		3,194
	December 31, 2014	Level 1		Level 2		Level 3		Total
	Other real estate and repossessed assets	$	—		—		1,380		1,380
	Impaired loans		—		—		4,865		4,865
	The carrying amounts and estimated fair values of the Company’s financial instruments at March 31, 2015 and December 31, 2014 were as follows:
		Carrying		Estimated Fair Value
	March 31, 2015	Amount		Level 1		Level 2		Level 3
	Assets:
	Cash and cash equivalents	$	149,907		149,907		—		—
	Investment securities held-to-maturity		5,730				5,730
	Investment securities available-for-sale		31,901				31,901		—
Other investments		5,844		—		5,844		—
Loans, net		911,218		—		908,374		3,194
Mortgage loans held-for-sale		13,804		—		13,804		—
Bank owned life insurance		11,762		—		11,762		—
Derivative assets		418		—		418		—
Liabilities:
Deposits		1,000,217		—		978,924		—
Federal Home Loan Bank advances		22,000		—		22,674		—
Derivative liabilities		716		—		716		—
	Carrying		Estimated Fair Value
December 31, 2014	Amount		Level 1		Level 2		Level 3
Assets:
Cash and cash equivalents	$	123,435		123,435		—		—
Investment securities available-for-sale		34,932		1,501		33,431		—
Other investments		5,421		—		5,421		—
Loans, net		878,919		—		873,125		4,865
Mortgage loans held-for-sale		9,329		—		9,329		—
Bank owned life insurance		10,641		—		10,641		—
Derivative assets		105		—		105		—
Liabilities:
Deposits		971,060		—		949,621		—
Federal Home Loan Bank advances		22,000		—		22,677		—
Derivative liabilities		425		—		425		—
Limitations
Fair value estimates are made at a specific point in time, based on relevant market information and information about the financial instrument. These estimates do not reflect any premium or discount that could result from offering for sale at one time the Company’s entire holdings of a particular financial instrument. Because no market exists for a significant portion of the Company’s financial instruments, fair value estimates are based on many judgments. These estimates are subjective in nature and involve uncertainties and matters of significant judgment and therefore cannot be determined with precision. Changes in assumptions could significantly affect the estimates.
Fair value estimates are based on existing on- and off-balance sheet financial instruments without attempting to estimate the value of anticipated future business and the value of assets and liabilities that are not considered financial instruments. Significant assets and liabilities that are not considered financial instruments include mortgage banking operations, deferred income taxes, and premises and equipment. In addition, the tax ramifications related to the realization of the unrealized gains and losses can have a significant effect on fair value estimates and have not been considered in the estimates.

Sale_of_Common_Stock_and_Initi

Sale of Common Stock and Initial Public Offering	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Sale of Common Stock and Initial Public Offering	Note 7 – Sale of Common Stock and Initial Public Offering
	On March 18, 2015, the Company sold 1,642,000 shares of common stock at $19.50 in its initial public offering. The underwriters had an option to purchase an additional 255,000 shares, which option they exercised on March 27, 2015. In total, the Company sold 1,897,000 shares and raised approximately $33.9 million, net of offering expenses. The Company’s stock is traded on the Nasdaq Global Select Market under the symbol “NCOM.”

Segment_Reporting

Segment Reporting	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segment Reporting	Note 8 – Segment Reporting
	The Company’s three reportable segments represent distinct product lines and are viewed separately for strategic planning purposes and internal reporting. There are no amounts to report for the receivables factoring segment for the 2014 period, as this business was not acquired until August 29, 2014. The following table is a reconciliation of the reportable segment revenues, expenses and profit to the Company’s consolidated totals.
			Retail and
			Commercial		Mortgage		Receivables			Elimination
			Banking		Division (1)		Factoring			Entries (2)			Total
	Three Months Ended March 31, 2015:
	Interest income		$	9,516		84		3,113			(520	)		12,193
	Interest expense			999		28		520			(520	)		1,027
	Net interest income			8,517		56		2,593			—			11,166
	Provision for loan and lease losses			—		—		161			—			161
	Noninterest income			547		1,187		30			—			1,764
	Noninterest expense			6,916		1,040		1,334			—			9,290
	Net earnings before tax and noncontrolling interest			2,148		203		1,128			—			3,479
	Income tax expense			763		77		252			—			1,092
	Noncontrolling interest			—		—		(466	)		—			(466	)
	Net earnings atributable to National Commerce Corporation		$	1,385		126		410			—			1,921
	Total assets as of March 31, 2015		$	1,164,877		13,804		93,923			(65,937	)		1,206,667
	Three Months Ended March 31, 2014:
	Interest income		$	6,138		70		—			—			6,208
	Interest expense			639		20		—			—			659
	Net interest income			5,499		50		—			—			5,549
	Provision for loan and lease losses			—		—		—			—			—
	Noninterest income			158		809		—			—			967
	Noninterest expense			4,112		769		—			—			4,881
	Net earnings before tax and noncontrolling interest			1,545		90		—			—			1,635
	Income tax expense			558		34		—			—			592
	Noncontrolling interest			—		—		—			—			—
	Net earnings atributable to National Commerce Corporation		$	987		56		—			—			1,043
	Total assets as of March 31, 2014		$	740,701		10,302		—			—			751,003
	-1	Noninterest income for the Mortgage Division includes intercompany income allocation.
	-2	Entry to remove intercompany interest allocated to the Receivables Factoring segment. For segment reporting purposes, we allocate funding costs of Fed Funds plus 2.5% to the Receivables Factoring segment.

Goodwill_and_Intangibles

Goodwill and Intangibles	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangibles	Note 9 – Goodwill and Intangibles
	Changes to the carrying amount of goodwill for the three months ended March 31, 2015 are provided in the following table.
	Balance, December 31, 2014	$	28,834
	Adjustments to goodwill		80
	Balance, March 31, 2015	$	28,914
	The adjustments to goodwill made during the three months ended March 31, 2015 resulted from the write-off of fixed assets and prepaid assets acquired in the United acquisition. The adjustments were made as additional information that existed at the time of acquisition was reviewed and affected the recorded fair value of certain fixed assets and prepaid assets. Net of deferred taxes, the adjustment resulted in an $80,000 increase to goodwill recorded in the United acquisition. The adjustment to goodwill had no impact on net income or shareholders’ equity of the Company for the first three months of 2015.
	A summary of core deposit intangible assets as of March 31, 2015 and December 31, 2014 is as follows.
		March 31, 2015		December 31, 2014
	Gross carrying amount	$	1,776	$	1,776
	Less: accumulated amortization		130		19
	Net carrying amount	$	1,646	$	1,757

Cash_and_Cash_Equivalents

Cash and Cash Equivalents	3 Months Ended
	Mar. 31, 2015
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Note 10 – Cash and Cash Equivalents
	Cash equivalents include amounts due from banks, interest-bearing deposits with the Federal Reserve Bank of Atlanta (“FRB”), the Federal Home Loan Bank and correspondent banks, and federal funds sold. Generally, federal funds are sold for one-day periods. The Company is required to maintain average reserve balances with the FRB or in cash. At March 31, 2015 and December 31, 2014, the Company’s reserve requirements were approximately $10,923,000 and $2,436,000, respectively.

Recently_Issued_Accounting_Pro

Recently Issued Accounting Pronouncements	3 Months Ended
	Mar. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Note 11 – Recently Issued Accounting Pronouncements
	In August 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements – Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. These amendments are intended to reduce diversity in the timing and content of going concern disclosures. This ASU clarifies management’s responsibility to evaluate and provide related disclosures if there are any conditions or events, as a whole, that raise substantial doubt about the entity’s ability to continue as a going concern for one year after the date on which the financial statements are issued (or, if applicable, available to be issued). The amendments in this ASU will be effective for the annual period ending after December 15, 2016, and for annual and interim periods thereafter. Early adoption is permitted. The Company does not believe that this ASU will have an impact on its financial position or results of operations.
	In November 2014, the FASB issued ASU No. 2014-16, Determining Whether the Host Contract in a Hybrid Financial Instrument Issued in the Form of a Share is More Akin to Debt or to Equity. The amendment is intended to address how current U.S. GAAP should be interpreted in evaluating the economic characteristics and risks of a host contract in a hybrid financial instrument that is issued in the form of a share. The amendments in this update will be effective for interim and annual periods beginning after December 15, 2015, although early adoption is permitted. The adoption of this ASU will not have a significant impact on the Company’s financial position or results of operations.
	In February 2015, the FASB issued ASU No. 2015-02, Amendments to the Consolidation Analysis. The amendment substantially changes the way that reporting entities are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the new amendment. Specifically, the amendments modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities (VIEs) or voting interest entities, eliminate the presumption that a general partner should consolidate a limited partnership, and affect the consolidation analysis of reporting entities that are involved with VIEs. The amendments in this update will be effective for interim and annual periods beginning after December 15, 2015. Early adoption is permitted. The standard permits the use of either the retrospective or cumulative effect transition method. The adoption of this ASU will not have a significant impact on the Company’s financial position or results of operations.

Recently_Issued_Accounting_Pro1

Recently Issued Accounting Pronouncements (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Changes and Error Corrections [Abstract]
Presentation of Financial Statements - Going Concern	In August 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) No. 2014-15, Presentation of Financial Statements – Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern. These amendments are intended to reduce diversity in the timing and content of going concern disclosures. This ASU clarifies management’s responsibility to evaluate and provide related disclosures if there are any conditions or events, as a whole, that raise substantial doubt about the entity’s ability to continue as a going concern for one year after the date on which the financial statements are issued (or, if applicable, available to be issued). The amendments in this ASU will be effective for the annual period ending after December 15, 2016, and for annual and interim periods thereafter. Early adoption is permitted. The Company does not believe that this ASU will have an impact on its financial position or results of operations.

Net_Earnings_per_Common_Share_

Net Earnings per Common Share (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Reconciliation of Components of Basic and Diluted Earnings Per Share	The reconciliation of the components of the basic and diluted earnings per share is as follows.
		For the Three Months Ended
		March 31,
		2015		2014
	Net earnings available to common shareholders	$	1,921		1,043
	Weighted average common shares outstanding		7,701,663		5,730,780
	Dilutive effect of stock options		33,078		9,859
	Dilutive effect of directors’ shares		3,147		—
	Dilutive effect of performance share awards		63,689		35,161
	Diluted common shares		7,801,577		5,775,800
	Basic earnings per common share		0.25		0.18
	Diluted earnings per common share	$	0.25		0.18

Securities_Tables

Securities (Tables)	3 Months Ended
	Mar. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Schedule of Amortized Cost and Fair Value of Held-to-Maturity Debt Securities	The amortized cost and fair value of held-to-maturity and available-for-sale debt securities at March 31, 2015 and December 31, 2014 were as follows.
		Held-to-Maturity Securities
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
	March 31, 2015	Cost		Gains		Losses		Value
	Municipal securities	$	5,730		—		—		5,730
		$	5,730		—		—		5,730
Schedule of Amortized Cost and Fair Value of Available-for-Sale Debt Securities	The amortized cost and fair value of held-to-maturity and available-for-sale debt securities at March 31, 2015 and December 31, 2014 were as follows.
		Available-for-Sale Securities
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
	March 31, 2015	Cost		Gains		Losses		Value
	Mortgage-backed securities	$	26,135		1,155		58		27,232
	Municipal securities		4,408		273		12		4,669
		$	30,543		1,428		70		31,901
				Gross		Gross		Estimated
		Amortized		Unrealized		Unrealized		Fair
	December 31, 2014	Cost		Gains		Losses		Value
	U.S. Treasury securities	$	1,501		—		—		1,501
	Mortgage-backed securities		27,723		1,138		111		28,750
	Municipal securities		4,408		279		6		4,681
		$	33,632		1,417		117		34,932
Schedule of Available-for-Sale Investment Securities with Unrealized Losses	Details concerning the Company’s debt securities with unrealized losses as of March 31, 2015 and December 31, 2014 are as follows.
		Available-for-Sale Securities
		31-Mar-15
		Less than 12 Months				12 Months or More				Total
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	Mortgage-backed securities	$	—		—		7,142		58		7,142		58
	Municipal securities		—		—		488		12		488		12
		$	—		—		7,630		70		7,630		70
		31-Dec-14
		Less than 12 Months				12 Months or More				Total
		Fair		Unrealized		Fair		Unrealized		Fair		Unrealized
		Value		Losses		Value		Losses		Value		Losses
	U.S. Treasury securities	$	—		—		—		—		—		—
	Mortgage-backed securities		—		—		7,705		111		7,705		111
	Municipal securities		—		—		494		6		494		6
		$	—		—		8,199		117		8,199		117
Schedule of Amortized Cost and Estimated Fair Value of Securities	The amortized cost and estimated fair value of debt securities at March 31, 2015, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers have the right to call or prepay obligations with or without call or prepayment penalties.
		Available-for-Sale Securities				Held-to-Maturity Securities
		Amortized		Fair		Amortized		Fair
		Cost		Value		Cost		Value
	Municipal securities:
	0 to 5 years	$	—		—	$	—		—
	5 to 10 years		1,047		1,107		—		—
	Over 10 years		3,361		3,562		5,730		5,730
	Mortgage-backed securities		26,135		27,232		—		—
		$	30,543		31,901	$	5,730		5,730

Loans_Allowance_for_Loan_Losse1

Loans, Allowance for Loan Losses and Credit Quality (Tables)	3 Months Ended
	Mar. 31, 2015
Receivables [Abstract]
Summary of Major Classifications of Loans	Major classifications of loans at March 31, 2015 and December 31, 2014 are summarized as follows.
		March 31, 2015			December 31, 2014
	Commercial, financial and agricultural	$	141,209			131,657
	Factored commercial receivables		69,541			82,600
	Real estate - mortgage		604,056			577,268
	Real estate - construction		90,263			83,663
	Consumer		16,217			13,962
			921,286			889,150
	Less: Unearned fees		546			429
	Total loans and leases		920,740			888,721
	Allowance for loan losses		(9,522	)		(9,802	)
	Total net loans and leases	$	911,218			878,919
Summary of Allowance for Loan Losses and Recorded Investment in Loans by Portfolio Segment	The following table presents the balance in the allowance for loan losses and the recorded investment in loans by portfolio segment and based on impairment method for the periods indicated. The acquired loans are not included in the allowance for loan losses calculation, as these loans are recorded at fair value, and there has been no further indication of credit deterioration that would require an additional provision.
		Commercial,			Factored
		financial and			commercial			Real estate -			Real estate -
	Balance, March 31, 2015	agricultural			receivables			mortgage			construction			Consumer			Unallocated			Total
	Balance, December 31, 2014	$	1,523			955			5,047			647			562			1,068			9,802
	Provisions charged to operating expense		(43	)		161			453			122			(245	)		(287	)		161
	Loans charged off		(1	)		(566	)		(332	)		—			—			—			(899	)
	Recoveries		20			406			24			8			—			—			458
	Balance, March 31, 2015	$	1,499			956			5,192			777			317			781			9,522
	Ending balance, individually evaluated for impairment	$	—			678						100			—			—			778
	Ending balance, collectively evaluated for impairment	$	1,499			278			5,192			677			317			781			8,744
	Loans:
	Individually evaluated for impairment	$	—			820			430			187			—			—			1,437
	Collectively evaluated for impairment	$	140,226			68,721			596,432			89,733			15,885			—			910,997
	Acquired loans with deteriorated credit quality	$	983			—			7,194			343			332			—			8,852
		Commercial,			Factored
		financial and			commercial			Real estate -			Real estate -
	Balance, March 31, 2014	agricultural			receivables			mortgage			construction			Consumer			Unallocated			Total
	Balance, December 31, 2013	$	1,398			—			4,449			964			243			2,065			9,119
	Provisions charged to operating expense		(98	)		—			159			(359	)		(192	)		490			—
	Loans charged off		—			—			—			—			(1	)		—			(1	)
	Recoveries		16			—			13			13			2			—			44
	Balance, March 31, 2014	$	1,316			—			4,621			618			52			2,555			9,162
	Ending balance, individually evaluated for impairment	$	—			—			—			—			—			—			—
	Ending balance, collectively evaluated for impairment	$	1,316			—			4,621			618			52			2,555			9,162
	Loans:
	Individually evaluated for impairment	$	92			—			3,225			—			—			—			3,317
	Collectively evaluated for impairment	$	84,958			—			407,807			55,576			6,110			—			554,451
Summary of Impaired Loans by Class of Loans	The following tables present impaired loans by class of loans as of March 31, 2015 and December 31, 2014. The purchased credit impaired loans are not included in these tables because they are carried at fair value and accordingly have no related associated allowance.
					Unpaid						Average
		Recorded			Principal			Related			Recorded
	March 31, 2015	Investment			Balance			Allowance			Investment
	Impaired loans without related allowance:
	Commercial, financial and agricultural	$	—			151			—			—
	Factored commercial receivables		—			—			—			—
	Real estate - mortgage		2,921			4,805			—			1,987
	Real estate - construction		—			—			—			—
	Consumer		86			176			—			43
	Total	$	3,007			5,132			—			2,030
	Impaired loans with related allowance:
	Commercial, financial and agricultural	$	—			—			—			—
	Factored commercial receivables		820			820			678			1,213
	Real estate - mortgage		—			—			—			513
	Real estate - construction		187			187			100			193
	Consumer		—			—			—			—
	Total	$	1,007			1,007			778			1,919
	Total impaired loans:
	Commercial, financial and agricultural	$	—			151			—			—
	Factored commercial receivables		820			820			678			1,213
	Real estate - mortgage		2,921			4,805			—			2,500
	Real estate - construction		187			187			100			193
	Consumer		86			176			—			43
	Total	$	4,014			6,139			778			3,949
					Unpaid						Average
		Recorded			Principal			Related			Recorded
	December 31, 2014	Investment			Balance			Allowance			Investment
	Impaired loans without related allowance:
	Commercial, financial and agricultural	$	—			—			—			24
	Factored commercial receivables		—			—			—			—
	Real estate - mortgage		1,052			2,030			—			1,770
	Real estate - construction		—			—			—			—
	Consumer		—			—			—			—
	Total	$	1,052			2,030			—			1,794
	Impaired loans with related allowance:
	Commercial, financial and agricultural	$	—			—			—			—
	Factored commercial receivables		1,605			1,605			473			321
	Real estate - mortgage		1,026			1,026			350			205
	Real estate - construction		198			198			50			40
	Consumer		—			—			—			—
	Total	$	2,829			2,829			873			566
	Total impaired loans:
	Commercial, financial and agricultural	$	—			—			—			24
	Factored commercial receivables		1,605			1,605			473			321
	Real estate - mortgage		2,078			3,056			350			1,975
	Real estate - construction		198			198			50			40
	Consumer		—			—			—			—
	Total	$	3,881			4,859			873			2,360
Summary of Aging of Recorded Investment in Past Due and Non-accrual Loan	The following tables present the aging of the recorded investment in past due loans and non-accrual loan balances as of March 31, 2015 and December 31, 2014, by class of loans.
		30-59 Days			60-89 Days			> 90 Days			Total
	March 31, 2015	Past Due			Past Due			Past Due			Past Due			Current			Total			Non-accrual
	Commercial, financial and agricultural	$	—			—			—			—			141,209			141,209			—
	Factored commercial receivables		4,415			676			168			5,259			64,282			69,541			—
	Real estate - mortgage		345			—			866			1,211			602,845			604,056			2,921
	Real estate - construction		—			—			—			—			90,263			90,263			187
	Consumer		171			35			82			288			15,929			16,217			86
	Total	$	4,931			711			1,116			6,758			914,528			921,286			3,194
		30-59 Days			60-89 Days			> 90 Days			Total
	December 31, 2014	Past Due			Past Due			Past Due			Past Due			Current			Total			Non-accrual
	Commercial, financial and agricultural	$	—			—			—			—			131,657			131,657			—
	Factored commercial receivables		6,327			1,013			217			7,557			75,043			82,600			—
	Real estate - mortgage		191			1,963			1,572			3,726			573,542			577,268			4,133
	Real estate - construction		198			—			—			198			83,465			83,663			676
	Consumer		188			—			132			320			13,642			13,962			56
	Total	$	6,904			2,976			1,921			11,801			877,349			889,150			4,865
Summary of Risk Category of Loans by Class of Loans	As of March 31, 2015 and December 31, 2014, and based on the most recent analysis performed, the risk category of loans by class of loans was as follows.
	March 31, 2015	Pass			OAEM			Substandard			Doubtful			Total
	Commercial, financial and agricultural	$	138,689			800			1,720						141,209
	Factored commercial receivables		68,721			—			—			820			69,541
	Real estate - mortgage		593,247			4,525			3,363			2,921			604,056
	Real estate - construction		89,733			92			251			187			90,263
	Consumer		15,423			202			506			86			16,217
	Total	$	905,813			5,619			5,840			4,014			921,286
	December 31, 2014	Pass			OAEM			Substandard			Doubtful			Total
	Commercial, financial and agricultural	$	129,314			1,159			1,184			—			131,657
	Factored commercial receivables		80,995			—			—			1,605			82,600
	Real estate - mortgage		565,992			4,057			2,803			4,416			577,268
	Real estate - construction		82,552			94			254			763			83,663
	Consumer		13,192			201			477			92			13,962
	Total	$	872,045			5,511			4,718			6,876			889,150

Fair_Value_Measurements_and_Di1

Fair Value Measurements and Disclosures (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis	The table below presents the recorded amount of assets and liabilities measured at fair value on a recurring basis as of March 31, 2015 and December 31, 2014.
	March 31, 2015	Level 1		Level 2		Level 3		Total
	Mortgage-backed securities	$	—		27,232		—		27,232
	Municipal securities		—		4,669		—		4,669
	Total investment securities available-for-sale	$	—		31,901		—		31,901
	Derivative assets	$	—		418		—		418
	Derivative liabilities	$	—		716		—		716
	December 31, 2014	Level 1		Level 2		Level 3		Total
	U.S. Treasury securities	$	1,501		—		—		1,501
	Mortgage-backed securities		—		28,750		—		28,750
	Municipal securities		—		4,681		—		4,681
	Investment in mutual fund		—		—		—		—
	Total investment securities available-for-sale	$	1,501		33,431		—		34,932
	Derivative assets	$	—		105		—		105
	Derivative liabilities	$	—		425		—		425
Summary of Assets Measured at Fair Value on a Nonrecurring Basis	Assets measured at fair value on a nonrecurring basis are included in the table below as of March 31, 2015 and December 31, 2014.
	March 31, 2015	Level 1		Level 2		Level 3		Total
	Other real estate and repossessed assets	$	—		—		2,036		2,036
	Impaired loans		—		—		3,194		3,194
	December 31, 2014	Level 1		Level 2		Level 3		Total
	Other real estate and repossessed assets	$	—		—		1,380		1,380
	Impaired loans		—		—		4,865		4,865
Summary of Carrying Amounts and Estimated Fair Values of the Company's Financial Instruments	The carrying amounts and estimated fair values of the Company’s financial instruments at March 31, 2015 and December 31, 2014 were as follows:
		Carrying		Estimated Fair Value
	March 31, 2015	Amount		Level 1		Level 2		Level 3
	Assets:
	Cash and cash equivalents	$	149,907		149,907		—		—
	Investment securities held-to-maturity		5,730				5,730
	Investment securities available-for-sale		31,901				31,901		—
	Other investments		5,844		—		5,844		—
	Loans, net		911,218		—		908,374		3,194
	Mortgage loans held-for-sale		13,804		—		13,804		—
	Bank owned life insurance		11,762		—		11,762		—
	Derivative assets		418		—		418		—
	Liabilities:
	Deposits		1,000,217		—		978,924		—
	Federal Home Loan Bank advances		22,000		—		22,674		—
	Derivative liabilities		716		—		716		—
		Carrying		Estimated Fair Value
	December 31, 2014	Amount		Level 1		Level 2		Level 3
	Assets:
	Cash and cash equivalents	$	123,435		123,435		—		—
	Investment securities available-for-sale		34,932		1,501		33,431		—
	Other investments		5,421		—		5,421		—
	Loans, net		878,919		—		873,125		4,865
	Mortgage loans held-for-sale		9,329		—		9,329		—
	Bank owned life insurance		10,641		—		10,641		—
	Derivative assets		105		—		105		—
	Liabilities:
	Deposits		971,060		—		949,621		—
	Federal Home Loan Bank advances		22,000		—		22,677		—
	Derivative liabilities		425		—		425		—

Segment_Reporting_Tables

Segment Reporting (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Schedule of Reconciliation of Reportable Segment Revenue, Expenses and Profit	The following table is a reconciliation of the reportable segment revenues, expenses and profit to the Company’s consolidated totals.
			Retail and
			Commercial		Mortgage		Receivables			Elimination
			Banking		Division (1)		Factoring			Entries (2)			Total
	Three Months Ended March 31, 2015:
	Interest income		$	9,516		84		3,113			(520	)		12,193
	Interest expense			999		28		520			(520	)		1,027
	Net interest income			8,517		56		2,593			—			11,166
	Provision for loan and lease losses			—		—		161			—			161
	Noninterest income			547		1,187		30			—			1,764
	Noninterest expense			6,916		1,040		1,334			—			9,290
	Net earnings before tax and noncontrolling interest			2,148		203		1,128			—			3,479
	Income tax expense			763		77		252			—			1,092
	Noncontrolling interest			—		—		(466	)		—			(466	)
	Net earnings atributable to National Commerce Corporation		$	1,385		126		410			—			1,921
	Total assets as of March 31, 2015		$	1,164,877		13,804		93,923			(65,937	)		1,206,667
	Three Months Ended March 31, 2014:
	Interest income		$	6,138		70		—			—			6,208
	Interest expense			639		20		—			—			659
	Net interest income			5,499		50		—			—			5,549
	Provision for loan and lease losses			—		—		—			—			—
	Noninterest income			158		809		—			—			967
	Noninterest expense			4,112		769		—			—			4,881
	Net earnings before tax and noncontrolling interest			1,545		90		—			—			1,635
	Income tax expense			558		34		—			—			592
	Noncontrolling interest			—		—		—			—			—
	Net earnings atributable to National Commerce Corporation		$	987		56		—			—			1,043
	Total assets as of March 31, 2014		$	740,701		10,302		—			—			751,003
	-1	Noninterest income for the Mortgage Division includes intercompany income allocation.
	-2	Entry to remove intercompany interest allocated to the Receivables Factoring segment. For segment reporting purposes, we allocate funding costs of Fed Funds plus 2.5% to the Receivables Factoring segment.

Goodwill_and_Intangibles_Table

Goodwill and Intangibles (Tables)	3 Months Ended
	Mar. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Changes in Carrying Amount of Goodwill	Changes to the carrying amount of goodwill for the three months ended March 31, 2015 are provided in the following table.
	Balance, December 31, 2014	$	28,834
	Adjustments to goodwill		80
	Balance, March 31, 2015	$	28,914
Summary of Core Deposit Intangible Assets	A summary of core deposit intangible assets as of March 31, 2015 and December 31, 2014 is as follows.
		March 31, 2015		December 31, 2014
	Gross carrying amount	$	1,776	$	1,776
	Less: accumulated amortization		130		19
	Net carrying amount	$	1,646	$	1,757

Net_Earnings_per_Common_Share_1

Net Earnings per Common Share - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Abstract]
Anti-dilutive potential common shares are excluded from the diluted earnings per share computation	102,297	30,000

Net_Earnings_per_Common_Share_2

Net Earnings per Common Share - Reconciliation of Components of Basic and Diluted Earnings Per Share (Detail) (USD $)	3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share Reconciliation [Abstract]
Net earnings available to common shareholders	$1,921	$1,043
Weighted average common shares outstanding	7,701,663	5,730,780
Dilutive effect of stock options	33,078	9,859
Dilutive effect of directors' shares	3,147
Dilutive effect of performance share awards	63,689	35,161
Diluted common shares	7,801,577	5,775,800
Basic earnings per common share	$0.25	$0.18
Diluted earnings per common share	$0.25	$0.18

Securities_Schedule_of_Amortiz

Securities - Schedule of Amortized Cost and Fair Value of Held-to-Maturity Debt Securities (Detail) (USD $)	Mar. 31, 2015
In Thousands, unless otherwise specified
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities, Amortized Cost	$5,730
Held-to-Maturity Securities, Gross Unrealized Gains	0
Held-to-Maturity Securities, Gross Unrealized Losses	0
Held-to-Maturity Securities, Estimated Fair Value	5,730
Municipal Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Held-to-Maturity Securities, Amortized Cost	5,730
Held-to-Maturity Securities, Gross Unrealized Gains	0
Held-to-Maturity Securities, Gross Unrealized Losses	0
Held-to-Maturity Securities, Estimated Fair Value	$5,730

Securities_Schedule_of_Amortiz1

Securities - Schedule of Amortized Cost and Fair Value of Available-for-Sale Debt Securities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Securities, Amortized Cost	$30,543	$33,632
Available-for-Sale-Securities, Gross Unrealized Gains	1,428	1,417
Available-for-Sale-Securities, Gross Unrealized Losses	70	117
Available-for-Sale-Securities, Estimated Fair Value	31,901	34,932
Mortgage-Backed Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Securities, Amortized Cost	26,135	27,723
Available-for-Sale-Securities, Gross Unrealized Gains	1,155	1,138
Available-for-Sale-Securities, Gross Unrealized Losses	58	111
Available-for-Sale-Securities, Estimated Fair Value	27,232	28,750
Municipal Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Securities, Amortized Cost	4,408	4,408
Available-for-Sale-Securities, Gross Unrealized Gains	273	279
Available-for-Sale-Securities, Gross Unrealized Losses	12	6
Available-for-Sale-Securities, Estimated Fair Value	4,669	4,681
US Treasury Securities [Member]
Schedule of Available-for-sale Securities [Line Items]
Available-for-Sale Securities, Amortized Cost		1,501
Available-for-Sale-Securities, Estimated Fair Value		$1,501

Securities_Schedule_of_Availab

Securities - Schedule of Available-for-Sale Investment Securities with Unrealized Losses (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Gain (Loss) on Investments [Line Items]
Available-for-Sale Securities, Less than 12 Months Fair Value	$0	$0
Available-for-Sale Securities, Less than 12 Months Unrealized Losses	0	0
Available-for-Sale Securities, 12 Months or More Fair Value	7,630	8,199
Available-for-Sale Securities, 12 Months or More Unrealized Losses	70	117
Available-for-Sale Securities, Total Fair Value	7,630	8,199
Available-for-Sale Securities, Total Unrealized Losses	70	117
Mortgage-Backed Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-Sale Securities, Less than 12 Months Fair Value	0	0
Available-for-Sale Securities, Less than 12 Months Unrealized Losses	0	0
Available-for-Sale Securities, 12 Months or More Fair Value	7,142	7,705
Available-for-Sale Securities, 12 Months or More Unrealized Losses	58	111
Available-for-Sale Securities, Total Fair Value	7,142	7,705
Available-for-Sale Securities, Total Unrealized Losses	58	111
Municipal Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-Sale Securities, Less than 12 Months Fair Value	0	0
Available-for-Sale Securities, Less than 12 Months Unrealized Losses	0	0
Available-for-Sale Securities, 12 Months or More Fair Value	488	494
Available-for-Sale Securities, 12 Months or More Unrealized Losses	12	6
Available-for-Sale Securities, Total Fair Value	488	494
Available-for-Sale Securities, Total Unrealized Losses	12	6
US Treasury Securities [Member]
Gain (Loss) on Investments [Line Items]
Available-for-Sale Securities, Less than 12 Months Fair Value		0
Available-for-Sale Securities, Less than 12 Months Unrealized Losses		$0

Securities_Additional_Informat

Securities - Additional Information (Detail) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Investments, Debt and Equity Securities [Abstract]
Impairment charge	$0	$0
Proceeds from sale of securities available-for-sale	$0	$0

Securities_Schedule_of_Amortiz2

Securities - Schedule of Amortized Cost and Estimated Fair Value of Securities (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Available-for-Sale Securities, Amortized Cost	$30,543	$33,632
Available-for-Sale Securities, Fair Value	31,901	34,932
Held-to-Maturity Securities, Amortized Cost	5,730
Held-to-Maturity Securities, Fair Value	5,730
Municipal Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Available-for-Sale Securities 0 to 5 years, Amortized Cost	0
Available-for-Sale Securities 5 to 10 years, Amortized Cost	1,047
Available-for-Sale Securities Over 10 years, Amortized Cost	3,361
Available-for-Sale Securities, Amortized Cost	4,408	4,408
Available-for-Sale Securities 0 to 5 years, Fair Value	0
Available-for-Sale Securities 5 to 10 years, Fair Value	1,107
Available-for-Sale Securities Over 10 years, Fair Value	3,562
Available-for-Sale Securities, Fair Value	4,669	4,681
Held-to-Maturity Securities 0 to 5 years, Amortized Cost	0
Held-to-Maturity Securities 5 to 10 years, Amortized Cost	0
Held-to-Maturity Securities Over 10 years, Amortized Cost	5,730
Held-to-Maturity Securities, Amortized Cost	5,730
Held-to-Maturity Securities 0 to 5 years, Fair Value	0
Held-to-Maturity Securities 5 to 10 years, Fair Value	0
Held-to-Maturity Securities Over 10 years, Fair Value	5,730
Held-to-Maturity Securities, Fair Value	5,730
Mortgage-Backed Securities [Member]
Schedule Of Available For Sale Securities And Held To Maturity [Line Items]
Available-for-Sale Securities Mortgage-backed securities, Amortized Cost	26,135
Available-for-Sale Securities, Amortized Cost	26,135	27,723
Available-for-Sale Securities Mortgage-backed securities, Fair Value	27,232
Available-for-Sale Securities, Fair Value	27,232	28,750
Held-to-Maturity Securities Mortgage-backed securities, Amortized Cost	0
Held-to-Maturity Securities Mortgage-backed securities, Fair Value	$0

Loans_Allowance_for_Loan_Losse2

Loans, Allowance for Loan Losses and Credit Quality - Summary of Major Classifications of Loans (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	$921,286	$889,150
Less: Unearned fees	546	429
Total loans and leases	920,740	888,721
Allowance for loan losses	-9,522	-9,802	-9,162	-9,119
Total net loans and leases	911,218	878,919
Commercial, Financial and Agricultural [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	141,209	131,657
Allowance for loan losses	-1,499	-1,523	-1,316	-1,398
Real Estate - Mortgage [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	604,056	577,268
Allowance for loan losses	-5,192	-5,047	-4,621	-4,449
Real Estate - Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	90,263	83,663
Allowance for loan losses	-777	-647	-618	-964
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	16,217	13,962
Allowance for loan losses	-317	-562	-52	-243
Factored Commercial Receivables [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and leases	69,541	82,600
Allowance for loan losses	($956)	($955)

Loans_Allowance_for_Loan_Losse3

Loans, Allowance for Loan Losses and Credit Quality - Summary of Allowance for Loan Losses (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	$9,802	$9,119
Provisions charged to operating expense	161
Loans charged off	-899	-1
Recoveries	458	44
Balance, end of year	9,522	9,162
Ending balance, individually evaluated for impairment	778
Ending balance, collectively evaluated for impairment	8,744	9,162
Loans:
Individually evaluated for impairment	1,437	3,317
Collectively evaluated for impairment	910,997	554,451
Acquired loans with deteriorated credit quality	8,852
Factored Commercial Receivables [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	955
Provisions charged to operating expense	161
Loans charged off	-566
Recoveries	406
Balance, end of year	956
Ending balance, individually evaluated for impairment	678
Ending balance, collectively evaluated for impairment	278
Loans:
Individually evaluated for impairment	820
Collectively evaluated for impairment	68,721
Commercial, Financial and Agricultural [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	1,523	1,398
Provisions charged to operating expense	-43	-98
Loans charged off	-1
Recoveries	20	16
Balance, end of year	1,499	1,316
Ending balance, collectively evaluated for impairment	1,499	1,316
Loans:
Individually evaluated for impairment		92
Collectively evaluated for impairment	140,226	84,958
Acquired loans with deteriorated credit quality	983
Real Estate - Mortgage [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	5,047	4,449
Provisions charged to operating expense	453	159
Loans charged off	-332
Recoveries	24	13
Balance, end of year	5,192	4,621
Ending balance, collectively evaluated for impairment	5,192	4,621
Loans:
Individually evaluated for impairment	430	3,225
Collectively evaluated for impairment	596,432	407,807
Acquired loans with deteriorated credit quality	7,194
Real Estate - Construction [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	647	964
Provisions charged to operating expense	122	-359
Recoveries	8	13
Balance, end of year	777	618
Ending balance, individually evaluated for impairment	100
Ending balance, collectively evaluated for impairment	677	618
Loans:
Individually evaluated for impairment	187
Collectively evaluated for impairment	89,733	55,576
Acquired loans with deteriorated credit quality	343
Consumer [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	562	243
Provisions charged to operating expense	-245	-192
Loans charged off		-1
Recoveries		2
Balance, end of year	317	52
Ending balance, collectively evaluated for impairment	317	52
Loans:
Collectively evaluated for impairment	15,885	6,110
Acquired loans with deteriorated credit quality	332
Unallocated [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, beginning of year	1,068	2,065
Provisions charged to operating expense	-287	490
Balance, end of year	781	2,555
Ending balance, collectively evaluated for impairment	$781	$2,555

Loans_Allowance_for_Loan_Losse4

Loans, Allowance for Loan Losses and Credit Quality - Impaired Loans by Class of Loans (Detail) (USD $)	3 Months Ended	12 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Financing Receivable, Impaired [Line Items]
Impaired loans without related allowance, Recorded Investment	$3,007	$1,052
Impaired loans without related allowance, Unpaid Principal Balance	5,132	2,030
Impaired loans without related allowance, Average Recorded Investment	2,030	1,794
Impaired loans with related allowance, Recorded Investment	1,007	2,829
Impaired loans with related allowance, Unpaid Principal Balance	1,007	2,829
Total impaired loans, Related Allowance	778	873
Impaired loans with related allowance, Average Recorded Investment	1,919	566
Total impaired loans, Recorded Investment	4,014	3,881
Total impaired loans, Unpaid Principal Balance	6,139	4,859
Total impaired loans, Related Allowance	778	873
Total impaired loans, Average Recorded Investment	3,949	2,360
Commercial, Financial and Agricultural [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without related allowance, Unpaid Principal Balance	151
Impaired loans without related allowance, Average Recorded Investment		24
Total impaired loans, Unpaid Principal Balance	151
Total impaired loans, Average Recorded Investment		24
Real Estate - Mortgage [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without related allowance, Recorded Investment	2,921	1,052
Impaired loans without related allowance, Unpaid Principal Balance	4,805	2,030
Impaired loans without related allowance, Average Recorded Investment	1,987	1,770
Impaired loans with related allowance, Recorded Investment		1,026
Impaired loans with related allowance, Unpaid Principal Balance		1,026
Total impaired loans, Related Allowance		350
Impaired loans with related allowance, Average Recorded Investment	513	205
Total impaired loans, Recorded Investment	2,921	2,078
Total impaired loans, Unpaid Principal Balance	4,805	3,056
Total impaired loans, Related Allowance		350
Total impaired loans, Average Recorded Investment	2,500	1,975
Real Estate - Construction [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with related allowance, Recorded Investment	187	198
Impaired loans with related allowance, Unpaid Principal Balance	187	198
Total impaired loans, Related Allowance	100	50
Impaired loans with related allowance, Average Recorded Investment	193	40
Total impaired loans, Recorded Investment	187	198
Total impaired loans, Unpaid Principal Balance	187	198
Total impaired loans, Related Allowance	100	50
Total impaired loans, Average Recorded Investment	193	40
Consumer [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans without related allowance, Recorded Investment	86
Impaired loans without related allowance, Unpaid Principal Balance	176
Impaired loans without related allowance, Average Recorded Investment	43
Total impaired loans, Recorded Investment	86
Total impaired loans, Unpaid Principal Balance	176
Total impaired loans, Average Recorded Investment	43
Factored Commercial Receivables [Member]
Financing Receivable, Impaired [Line Items]
Impaired loans with related allowance, Recorded Investment	820	1,605
Impaired loans with related allowance, Unpaid Principal Balance	820	1,605
Total impaired loans, Related Allowance	678	473
Impaired loans with related allowance, Average Recorded Investment	1,213	321
Total impaired loans, Recorded Investment	820	1,605
Total impaired loans, Unpaid Principal Balance	820	1,605
Total impaired loans, Related Allowance	678	473
Total impaired loans, Average Recorded Investment	$1,213	$321

Loans_Allowance_for_Loan_Losse5

Loans, Allowance for Loan Losses and Credit Quality - Summary of Aging of Recorded Investment in Past Due and Non-accrual Loan (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	$4,931	$6,904
60-89 Days Past Due	711	2,976
> 90 Days Past Due	1,116	1,921
Total Past Due	6,758	11,801
Current	914,528	877,349
Total	921,286	889,150
Non-accrual	3,194	4,865
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current	141,209	131,657
Total	141,209	131,657
Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	345	191
60-89 Days Past Due		1,963
> 90 Days Past Due	866	1,572
Total Past Due	1,211	3,726
Current	602,845	573,542
Total	604,056	577,268
Non-accrual	2,921	4,133
Real Estate - Construction [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due		198
Total Past Due		198
Current	90,263	83,465
Total	90,263	83,663
Non-accrual	187	676
Consumer [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	171	188
60-89 Days Past Due	35
> 90 Days Past Due	82	132
Total Past Due	288	320
Current	15,929	13,642
Total	16,217	13,962
Non-accrual	86	56
Factored Commercial Receivables [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
30-59 Days Past Due	4,415	6,327
60-89 Days Past Due	676	1,013
> 90 Days Past Due	168	217
Total Past Due	5,259	7,557
Current	64,282	75,043
Total	$69,541	$82,600

Loans_Allowance_for_Loan_Losse6

Loans, Allowance for Loan Losses and Credit Quality - Summary of Risk Category of Loans By Class of Loans (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Financing Receivable, Recorded Investment [Line Items]
Loans	$921,286	$889,150
Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	141,209	131,657
Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	604,056	577,268
Real Estate - Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	90,263	83,663
Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	16,217	13,962
Factored Commercial Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	69,541	82,600
Pass [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	905,813	872,045
Pass [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	138,689	129,314
Pass [Member] | Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	593,247	565,992
Pass [Member] | Real Estate - Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	89,733	82,552
Pass [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	15,423	13,192
Pass [Member] | Factored Commercial Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	68,721	80,995
OAEM [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	5,619	5,511
OAEM [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	800	1,159
OAEM [Member] | Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,525	4,057
OAEM [Member] | Real Estate - Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	92	94
OAEM [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	202	201
Substandard [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	5,840	4,718
Substandard [Member] | Commercial, Financial and Agricultural [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	1,720	1,184
Substandard [Member] | Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	3,363	2,803
Substandard [Member] | Real Estate - Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	251	254
Substandard [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	506	477
Doubtful [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	4,014	6,876
Doubtful [Member] | Real Estate - Mortgage [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	2,921	4,416
Doubtful [Member] | Real Estate - Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	187	763
Doubtful [Member] | Consumer [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	86	92
Doubtful [Member] | Factored Commercial Receivables [Member]
Financing Receivable, Recorded Investment [Line Items]
Loans	$820	$1,605

Fair_Value_Measurements_and_Di2

Fair Value Measurements and Disclosures - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	$27,232	$28,750
Investment in mutual fund	31,901	34,932
Derivative assets	418	105
Derivative liabilities	716	425
Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in mutual fund	4,669	4,681
US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in mutual fund		1,501
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in mutual fund		1,501
Level 1 [Member] | US Treasury Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in mutual fund		1,501
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Mortgage-backed securities	27,232	28,750
Investment in mutual fund	31,901	33,431
Derivative assets	418	105
Derivative liabilities	716	425
Level 2 [Member] | Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Investment in mutual fund	$4,669	$4,681

Fair_Value_Measurements_and_Di3

Fair Value Measurements and Disclosures - Summary of Assets Measured at Fair Value on Nonrecurring Basis (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate and repossessed assets	$2,036	$1,380
Impaired loans	3,194	4,865
Doubtful [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	3,194	4,865
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Other real estate and repossessed assets	2,036	1,380
Level 3 [Member] | Doubtful [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$3,194	$4,865

Fair_Value_Measurements_and_Di4

Fair Value Measurements and Disclosures - Summary of Carrying Amounts and Estimated Fair Values of Financial Instruments (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014	Mar. 31, 2014	Dec. 31, 2013
In Thousands, unless otherwise specified
Assets
Cash and cash equivalents	$149,907	$123,435	$105,406	$124,136
Investment securities held-to-maturity	5,730
Investment securities available-for-sale	31,901	34,932
Other investments	5,844	5,421
Loans, net	911,218	878,919
Mortgage loans held-for-sale	13,804	9,329
Bank owned life insurance	11,762	10,641
Derivative assets	418	105
Liabilities:
Deposits	1,000,217	971,060
Federal Home Loan Bank advances	22,000	22,000
Derivative liabilities	716	425
Level 1 [Member]
Assets
Investment securities available-for-sale		1,501
Level 2 [Member]
Assets
Investment securities available-for-sale	31,901	33,431
Derivative assets	418	105
Liabilities:
Derivative liabilities	716	425
Estimated Fair Value [Member] | Level 1 [Member]
Assets
Cash and cash equivalents	149,907	123,435
Investment securities available-for-sale		1,501
Estimated Fair Value [Member] | Level 2 [Member]
Assets
Investment securities held-to-maturity	5,730
Investment securities available-for-sale	31,901	33,431
Other investments	5,844	5,421
Loans, net	908,374	873,125
Mortgage loans held-for-sale	13,804	9,329
Bank owned life insurance	11,762	10,641
Derivative assets	418	105
Liabilities:
Deposits	978,924	949,621
Federal Home Loan Bank advances	22,674	22,677
Derivative liabilities	716	425
Estimated Fair Value [Member] | Level 3 [Member]
Assets
Loans, net	$3,194	$4,865

Sale_of_Common_Stock_and_Initi1

Sale of Common Stock and Initial Public Offering - Additional Information (Detail) (USD $)	0 Months Ended		3 Months Ended
In Thousands, except Share data, unless otherwise specified	Mar. 27, 2015	Mar. 18, 2015	Mar. 31, 2015	Mar. 18, 2015
Class of Stock [Line Items]
Net proceeds from sale of common stock			$33,891
IPO [Member]
Class of Stock [Line Items]
Number of shares sold		1,642,000	1,897,000
Net proceeds from sale of common stock			$33,900
Common stock per share		$19.50		$19.50
Stock options exercised	255,000

Segment_Reporting_Additional_I

Segment Reporting - Additional Information (Detail)	3 Months Ended
	Mar. 31, 2015
	Segments
Segment Reporting [Abstract]
Number of reportable segments	3

Segment_Reporting_Schedule_of_

Segment Reporting - Schedule of Reconciliation of Reportable Segment Revenue, Expenses and Profit (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	$12,193	$6,208
Interest expense	1,027	659
Net interest income	11,166	5,549
Provision for loan and lease losses	161
Noninterest income	1,764	967
Noninterest expense	9,290	4,881
Earnings before income taxes	3,479	1,635
Income tax expense	1,092	592
Noncontrolling interest	-466
Net earnings attributable to National Commerce Corporation	1,921	1,043
Total assets	1,206,667	751,003	1,138,426
Operating Segments [Member] | Retail and Commercial Banking [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	9,516	6,138
Interest expense	999	639
Net interest income	8,517	5,499
Noninterest income	547	158
Noninterest expense	6,916	4,112
Earnings before income taxes	2,148	1,545
Income tax expense	763	558
Net earnings attributable to National Commerce Corporation	1,385	987
Total assets	1,164,877	740,701
Operating Segments [Member] | Mortgage Division [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	84	70
Interest expense	28	20
Net interest income	56	50
Noninterest income	1,187	809
Noninterest expense	1,040	769
Earnings before income taxes	203	90
Income tax expense	77	34
Net earnings attributable to National Commerce Corporation	126	56
Total assets	13,804	10,302
Operating Segments [Member] | Receivables Factoring [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	3,113
Interest expense	520
Net interest income	2,593
Provision for loan and lease losses	161
Noninterest income	30
Noninterest expense	1,334
Earnings before income taxes	1,128
Income tax expense	252
Noncontrolling interest	-466
Net earnings attributable to National Commerce Corporation	410
Total assets	93,923
Elimination Entries [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Interest income	-520
Interest expense	-520
Total assets	($65,937)

Goodwill_and_Intangibles_Sched

Goodwill and Intangibles - Schedule of Changes in Carrying Amount of Goodwill (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Intangible Liability Disclosure [Abstract]
Beginning balance	$28,834
Adjustments to goodwill	80
Ending balance	$28,914

Goodwill_and_Intangibles_Summa

Goodwill and Intangibles - Summary of Core Deposit Intangible Assets (Detail) (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Intangible Liability Disclosure [Abstract]
Gross carrying amount	$1,776	$1,776
Less: accumulated amortization	130	19
Net carrying amount	$1,646	$1,757

Goodwill_and_Intangibles_Addit

Goodwill and Intangibles - Additional Information (Detail) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015
Intangible Liability Disclosure [Abstract]
Goodwill period increase decrease	$80

Segment_Reporting_Schedule_of_1

Segment Reporting - Schedule of Reconciliation of Reportable Segment Revenue, Expenses and Profit (Parenthetical) (Detail) (Receivables Factoring [Member])	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Receivables Factoring [Member]
Segment Reporting, Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Line Items]
Funding costs of fed funds percentage	2.50%	2.50%

Cash_and_Cash_Equivalents_Addi

Cash and Cash Equivalents - Additional Information (Detail) (USD $)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Cash and Cash Equivalents [Abstract]
Federal fund sold period	1 day
Reserve	$10,923,000	$2,436,000