Middlefield Banc (MBCN) S-4/A 18 Nov 16 Registration of securities issued in business combination transactions (amended) Financial data

Document and Entity Information

Document and Entity Information	9 Months Ended
	Sep. 30, 2016
Document Information [Line Items]
Document Type	S-4/A
Amendment Flag	true
AmendmentDescription	Amendment No. 1
Document Period End Date	Sep. 30, 2016
Trading Symbol	MBCN
Entity Registrant Name	MIDDLEFIELD BANC CORP
Entity Central Index Key	836,147
Entity Filer Category	Smaller Reporting Company

Consolidated Balance Sheet

Consolidated Balance Sheet - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
ASSETS
Cash and due from banks	$ 21,976	$ 22,421	$ 20,846
Federal funds sold	1,300	1,329	4,793
Cash and cash equivalents	23,276	23,750	25,639
Investment securities available for sale, at fair value	123,054	146,520	154,334
Loans held for sale	880	1,107	438
Loans	586,329	533,710	470,584
Less allowance for loan and lease losses	6,334	6,385	6,846
Net loans	579,995	527,325	463,738
Premises and equipment, net	9,921	9,772	9,980
Goodwill	4,559	4,559	4,559
Core deposit intangibles	46	76	116
Bank-owned life insurance	13,438	13,141	9,092
Other real estate owned	1,205	1,412	2,590
Accrued interest and other assets	5,884	7,477	7,045
TOTAL ASSETS	762,258	735,139	677,531
LIABILITIES
Noninterest-bearing demand	136,320	116,498	105,512
Interest-bearing demand	67,061	57,219	56,377
Money market	77,774	78,856	75,895
Savings	173,272	180,653	178,470
Time	184,915	191,221	169,858
Total deposits	639,342	624,447	586,112
Short-term borrowings	32,803	35,825	14,808
Other borrowings	9,713	9,939	10,624
Accrued interest and other liabilities	2,208	2,624	2,120
TOTAL LIABILITIES	684,066	672,835	613,664
STOCKHOLDERS' EQUITY
Common stock	47,812	36,191	35,529
Retained earnings	40,282	37,236	32,524
Accumulated other comprehensive income	3,616	2,395	2,548
Treasury stock, at cost	(13,518)	(13,518)	(6,734)
TOTAL STOCKHOLDERS' EQUITY	78,192	62,304	63,867
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 762,258	$ 735,139	$ 677,531

Consolidated Balance Sheet (Par

Consolidated Balance Sheet (Parenthetical) - $ / shares	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Common stock, shares authorized (in shares)	10,000,000	10,000,000	10,000,000
Common stock, shares issued (in shares)	2,636,830	2,263,403	2,242,025
Common stock, par value (in dollars per share)	$ 0	$ 0	$ 0
Common stock, shares outstanding (in shares)	2,250,665	1,877,238	2,052,495
Treasury stock, shares (in shares)	386,165	386,165	189,530

CONSOLIDATED STATEMENT OF INCOM

CONSOLIDATED STATEMENT OF INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Interest and fees on loans	$ 6,459	$ 5,971	$ 18,949	$ 17,656	$ 23,824	$ 22,726	$ 22,496
Interest-bearing deposits in other institutions	15	6	42	26	33	24	30
Federal funds sold	7	4	16	12	13	14	15
Taxable interest	235	341	865	1,115	1,467	1,896	2,514
Tax-exempt interest	687	809	2,227	2,373	3,160	3,127	3,044
Dividends on stock	17	20	74	70	98	87	79
Total interest and dividend income	7,420	7,151	22,173	21,252	28,595	27,874	28,178
Deposits	921	876	2,665	2,581	3,426	3,633	4,709
Short-term borrowings	49	30	288	100	194	148	178
Federal funds purchased							7
Other borrowings	14	20	47	66	83	118	166
Trust preferred securities	42	33	117	85	117	171	190
Total interest expense	1,026	959	3,117	2,832	3,820	4,070	5,250
Net interest income	6,394	6,192	19,056	18,420	24,775	23,804	22,928
Provision for loan losses	105	105	315	210	315	370	196
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	6,289	6,087	18,741	18,210	24,460	23,434	22,732
Service charges on deposit accounts	505	471	1,443	1,382	1,874	1,876	1,956
Investment securities gains, net		211	303	257	323	248	11
Earnings on bank-owned life insurance	101	101	297	262	624	276	280
Gain on sale of loans	129	113	322	286	329	237
Other income	242	212	694	679	894	951	898
Total noninterest income	977	1,108	3,059	2,866	4,044	3,588	3,145
Salaries and employee benefits	2,677	2,285	7,740	7,205	9,751	8,817	7,913
Occupancy expense	306	305	933	945	1,253	1,108	1,231
Equipment expense	221	249	700	706	944	963	950
Data processing costs	334	287	928	798	1,071	917	854
Ohio state franchise tax	186	75	448	225	300	342	618
Federal deposit insurance expense	132	120	396	352	472	449	516
Professional fees	547	229	1,057	825	1,247	1,086	1,174
Loss (gain) on other real estate owned	(49)	24	(52)	72	(48)	183	18
Advertising expense	206	195	604	586	721	488	445
Other real estate expense	97	116	299	449	611	387	410
Directors fees	102	98	330	343	451	403	403
Appraiser fees	114	97	334	327
ATM fees	102	89	296	295
Other expense	677	490	1,872	1,539	3,264	2,667	2,298
Total noninterest expense	5,662	4,669	15,915	14,697	20,077	17,850	16,870
Income before income taxes	1,604	2,526	5,885	6,379	8,427	9,172	9,007
Income taxes	261	544	1,129	1,264	1,562	1,992	1,979
NET INCOME	$ 1,343	$ 1,982	$ 4,756	$ 5,115	$ 6,865	$ 7,180	$ 7,028
EARNINGS PER SHARE
Basic (in Dollars per share)	$ 0.60	$ 0.96	$ 2.31	$ 2.49	$ 3.41	$ 3.52	$ 3.48
Diluted (in dollars per share)	$ 0.60	$ 0.96	$ 2.31	$ 2.47	3.39	3.50	3.47
DIVIDENDS DECLARED PER SHARE (in Dollars per share)					$ 1.07	$ 1.04	$ 1.04
Core Deposits [Member]
Core deposit intangible amortization	$ 10	$ 10	$ 30	$ 30	$ 40	$ 40	$ 40

CONSOLIDATED STATEMENT OF COMPR

CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income	$ 1,343	$ 1,982	$ 4,756	$ 5,115	$ 6,865	$ 7,180	$ 7,028
Other comprehensive income (loss):
Net unrealized holding gain (loss) on available-for-sale securities	(400)	1,416	2,153	(699)	91	7,498	(11,545)
Tax effect	137	(481)	(732)	238	(31)	(2,549)	3,925
Reclassification adjustment for investment securities gains included in net income		(211)	(303)	(257)	(323)	(248)	(11)
Tax effect		71	103	87	110	84	3
Period change	(263)	795	1,221	(631)	(153)	4,785	(7,628)
Comprehensive income	$ 1,080	$ 2,777	$ 5,977	$ 4,484	$ 6,712	$ 11,965	$ (600)

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Retained Earnings [Member]	AOCI Attributable to Parent [Member]	Treasury Stock [Member]
Balance at Dec. 31, 2012	$ 55,437	$ 34,295	$ 22,485	$ 5,391	$ (6,734)
Balance (in Shares) at Dec. 31, 2012		2,181,763
Net income	7,028		7,028
Comprehensive income (loss)	(7,628)			(7,628)
Common stock issuance, net of issuance cost ($139)	74	$ 74
Common stock issuance, net of issuance cost ($139) (in Shares)		13,320
Dividend reinvestment and purchase plan, amount	736	$ 736
Dividend reinvestment and purchase plan, shares (in Shares)		25,751
Stock options exercised	(77)	$ (126)	49
Stock options exercised (in Shares)		1,000
Cash dividends	(2,097)		(2,097)
Balance at Dec. 31, 2013	53,473	$ 34,979	27,465	(2,237)	(6,734)
Balance (in Shares) at Dec. 31, 2013		2,221,834
Net income	7,180		7,180
Comprehensive income (loss)	4,785			4,785
Dividend reinvestment and purchase plan, amount	590	$ 590
Dividend reinvestment and purchase plan, shares (in Shares)		19,791
Stock options exercised	$ (50)	$ (50)
Stock options exercised (in Shares)	11,223
Stock-based compensation	$ 10	$ 10
Stock-based compensation (in Shares)		400
Cash dividends	(2,121)		(2,121)
Balance at Dec. 31, 2014	$ 63,867	$ 35,529	32,524	2,548	(6,734)
Balance (in Shares) at Dec. 31, 2014	2,052,495	2,242,025
Net income	$ 6,865		6,865
Comprehensive income (loss)	(153)			(153)
Purchase of treasury stock (196,635 shares)	(6,784)				(6,784)
Dividend reinvestment and purchase plan, amount	651	$ 651
Dividend reinvestment and purchase plan, shares (in Shares)		20,393
Stock options exercised	$ (7)	$ (7)
Stock options exercised (in Shares)	2,175	400
Stock-based compensation	$ 18	$ 18
Stock-based compensation (in Shares)		585
Cash dividends	(2,153)		(2,153)
Balance at Dec. 31, 2015	$ 62,304	$ 36,191	37,236	2,395	$ (13,518)
Balance (in Shares) at Dec. 31, 2015	1,877,238	2,263,403
Net income	$ 4,756		4,756
Comprehensive income (loss)	$ 1,221			1,221
Dividend reinvestment and purchase plan, shares (in Shares)					11,712
Stock options exercised (in Shares)	0
Stock-based compensation	$ 11,239	$ 11,239
Stock-based compensation (in Shares)	360,815
Dividend reinvestment and purchase plan (11,712 shares)	$ 382	382
Cash dividends	(1,710)		(1,710)
Balance at Sep. 30, 2016	$ 78,192	$ 47,812	$ 40,282	$ 3,616	$ (13,518)
Balance (in Shares) at Sep. 30, 2016	2,250,665

CONSOLIDATED STATEMENT OF CHAN7

CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS EQUITY (Parenthetical) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Common stock issuance, net of offering cost (in shares)	360,815
Common stock, issuance cost (in Dollars)				$ 139
Cash dividends (in dollars per share)		$ 1.07	$ 1.04	$ 1.04
Common Stock [Member]
Common stock issuance, net of offering cost (in shares)		585	400
Dividend reinvestment and purchase plan (in shares)		20,393	19,791	25,751
Cash dividends (in dollars per share)			$ 1.04	$ 1.04
Retained Earnings [Member]
Cash dividends (in dollars per share)	$ 0.81
Treasury Stock [Member]
Dividend reinvestment and purchase plan (in shares)	11,712
Purchase of treasury stock (in Shares)		196,635

Consolidated Statement of Cash

Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES
Net income	$ 4,756	$ 5,115	$ 6,865	$ 7,180	$ 7,028
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	315	210	315	370	196
Investment securities gain, net	(303)	(257)	(323)	(248)	(11)
Depreciation and amortization	774	763	1,013	1,049	891
Amortization of premium and discount on investment securities	352	553	669	737	1,100
Accretion of deferred loan fees, net	(150)	(468)	(603)	(237)	(245)
Origination of loans held for sale	(15,497)	(14,740)	(17,889)	(6,223)
Proceeds from sale of loans	16,046	14,844	17,549	6,022
Gain on sale of loans	(322)	(286)	(329)	(237)
Earnings on bank-owned life insurance	(297)	(262)	(624)	(276)	(280)
Deferred income tax	224	397	558	(154)	423
Stock-based compensation expense			18	10
Loss (gain) on other real estate owned	(52)	72	(48)	183	18
Other real estate owned writedowns	73	56	102	123	101
(Increase) decrease in accrued interest receivable	(139)	(481)	(292)	40	28
(Decrease) increase in accrued interest payable	(4)	58	80	(49)	(128)
Decrease in prepaid federal deposit insurance					513
Other, net	253	(158)	121	(831)	263
Net cash provided by operating activities	6,029	5,416	7,182	7,459	9,897
INVESTING ACTIVITIES
Proceeds from repayments and maturities	17,896	7,530	13,497	13,474	25,411
Proceeds from sale of securities	9,115	15,284	15,686	8,383	25,088
Purchases	(1,744)	(14,876)	(21,946)	(12,287)	(25,815)
Increase in loans, net	(53,430)	(40,554)	(63,937)	(36,222)	(29,829)
Proceeds from the sale of other real estate owned	781	1,094	1,762	832	882
Purchase of bank-owned life insurance		(4,000)	(4,000)
Purchase of premises and equipment	(679)	(454)	(507)	(902)	(1,834)
Net cash used for investing activities	(28,061)	(35,976)	(59,445)	(26,722)	(6,097)
FINANCING ACTIVITIES
Net increase (decrease) in deposits	14,895	40,436	38,335	17,276	(24,499)
Increase (Decrease) in short-term borrowings, net	(3,022)	(10,761)	21,017	3,999	4,271
Repayment of other borrowings	(226)	(324)	(685)	(985)	(1,361)
Common stock issued	11,239				74
Stock options exercised		6	(7)	(50)	(77)
Proceeds from dividend reinvestment and purchase plan	382	504	651	590	736
Purchase of treasury stock			(6,784)
Cash dividends	(1,710)	(1,645)	(2,153)	(2,121)	(2,097)
Net cash provided by (used for) financing activities	21,558	28,216	50,374	18,709	(22,953)
Increase (decrease) in cash and cash equivalents	(474)	(2,344)	(1,889)	(554)	(19,153)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD	23,750	25,639	25,639	26,193	45,346
CASH AND CASH EQUIVALENTS AT END OF PERIOD	23,276	23,295	23,750	25,639	26,193
SUPPLEMENTAL INFORMATION
Interest on deposits and borrowings	3,121	2,774	3,740	4,119	5,378
Income taxes	475	350	800	2,260	1,620
Non-cash investing transactions:
Transfers from loans to other real estate owned	$ 595	$ 638	638	$ 1,030	2,113
Loans to facilitate the sale of other real estate owned					$ (260)
Death benefit proceeds not yet received from insurance company			$ 575

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2015
Summary of Significant Accounting Policies	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES A summary of the significant accounting and reporting policies applied in the presentation of the accompanying financial statements follows: Nature of Operations and Basis of Presentation Middlefield Banc Corp. (the “Company”) is an Ohio corporation organized to become the holding company of The Middlefield Banking Company (“MBC”). MBC is a state-chartered bank located in Ohio. On April 19, 2007, Middlefield Banc Corp. acquired Emerald Bank (“EB”), an Ohio-chartered commercial bank headquartered in Dublin, Ohio. EB merged into MBC on January 20, 2014. On October 23, 2009, the Company established an asset resolution subsidiary named EMORECO, Inc. The Company and its subsidiaries derive substantially all of their income from banking and bank-related services, which includes interest earnings on residential real estate, commercial mortgage, commercial and consumer financings as well as interest earnings on investment securities and deposit services to its customers through ten locations. The Company is supervised by the Board of Governors of the Federal Reserve System, while MBC is subject to regulation and supervision by the Federal Deposit Insurance Corporation and the Ohio Division of Financial Institutions. The consolidated financial statements of the Company include its wholly owned subsidiaries, MBC and EMORECO, Inc. Significant intercompany items have been eliminated in preparing the consolidated financial statements. The financial statements have been prepared in conformity with U.S. Generally Accepted Accounting Principles. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the balance sheet date and revenues and expenses for the period. Actual results could differ from those estimates. Investment Securities Investment securities are classified at the time of purchase, based on management’s intention and ability, as securities held to maturity or securities available for sale. Debt securities acquired with the intent and ability to hold to maturity are stated at cost adjusted for amortization of premium and accretion of discount, which are computed using a level yield method and recognized as adjustments of interest income. Certain other debt securities have been classified as available for sale to serve principally as a source of liquidity. Unrealized holding gains and losses for available-for-sale securities are reported as a separate component of stockholders’ equity, net of tax, until realized. Realized security gains and losses are computed using the specific identification method. Interest and dividends on investment securities are recognized as income when earned. Securities are evaluated on at least a quarterly basis and more frequently when economic or market conditions warrant such an evaluation to determine whether a decline in their value is other than temporary. For debt securities, management considers whether the present value of cash flows expected to be collected are less than the security’s amortized cost basis (the difference defined as the credit loss), the magnitude and duration of the decline, the reasons underlying the decline and the Bank’s intent to sell the security or whether it is more likely than not that the Bank would be required to sell the security before its anticipated recovery in market value, to determine whether the loss in value is other than temporary. Once a decline in value is determined to be other than temporary, if the Bank does not intend to sell the security, and it is more likely than not that it will not be required to sell the security, before recovery of the security’s amortized cost basis, the charge to earnings is limited to the amount of credit loss. Any remaining difference between fair value and amortized cost (the difference defined as the non-credit portion) is recognized in other comprehensive income, net of applicable taxes. Otherwise, the entire difference between fair value and amortized cost is charged to earnings. For equity securities where the fair value has been significantly below cost for one year, the Bank’s policy is to recognize an impairment loss unless sufficient evidence is available that the decline is not other than temporary and a recovery period can be predicted. Restricted Stock Common stock of the Federal Home Loan Bank (“FHLB”) represents ownership in an institution that is wholly owned by other financial institutions. This equity security is accounted for at cost and classified with other assets. The FHLB of Cincinnati has reported profits for 2015 and 2014, remains in compliance with regulatory capital and liquidity requirements, and continues to pay dividends on the stock and make redemptions at the par value. With consideration given to these factors, management concluded that the stock was not impaired at December 31, 2015 or 2014. Mortgage Banking Activities Mortgage loans originated and intended for sale in the secondary market are carried at fair value. The Bank sells the loans on a servicing retained basis. Servicing rights are initially recorded at fair value with the income statement effect recorded in gains on sales of loans. The Bank measures servicing assets using the amortization method. Fair value is based on market prices for comparable mortgage servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. Loan servicing rights are amortized in proportion to and over the period of estimated net future servicing revenue. The expected period of the estimated net servicing income is based in part on the expected prepayment of the underlying mortgages. The unamortized balance of mortgage servicing rights is included in accrued interest and other assets on the Consolidated Balance Sheet. Mortgage servicing rights will be periodically evaluated for impairment, beginning in 2016. Impairment represents the excess of amortized cost over its estimated fair value. Impairment is determined by stratifying rights into tranches based on predominant risk characteristics, such as interest rate and original time to maturity. Any impairment is reported as a valuation allowance for an individual tranche. If the Company later determines that all or a portion of the impairment no longer exists for a particular grouping, a reduction of the allowance will be recorded as an increase to income. Servicing fee income is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of outstanding principal and are recorded as income when earned. The amortization of mortgage servicing rights is netted against loan servicing fee income. Late fees and ancillary fees related to loan servicing are not material. The Company is exposed to interest rate risk on loans held for sale and rate-lock loan commitments (“IRLCs”). As market interest rates increase or decrease, the fair value of loans held for sale and rate-lock commitments will decrease or increase. The Company enters into derivative transactions principally to protect against the risk of adverse interest movements affecting the value of the Company’s committed loan sales pipeline. In order to mitigate the risk that a change in interest rates will result in a decrease in value of the Company’s IRLCs in the committed mortgage pipeline or its loans held for sale, the Company enters into mandatory forward loan sales contracts with secondary market participants. Mandatory forward sales contracts and committed loans intended to be held for sale are considered free-standing derivative instruments and changes in fair value are recorded in current period earnings. For committed loans, fair value is measured using current market rates for the associated mortgage loans. For mandatory forward sales contracts, fair value is measured using secondary market pricing. Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff generally are reported at their outstanding unpaid principal balances net of the allowance for loan and lease losses. Interest income is recognized as income when earned on the accrual method. The accrual of interest is discontinued on a loan when management believes, after considering economic and business conditions, the borrower’s financial condition is such that collection of interest is doubtful. Interest received on nonaccrual loans is recorded as income or applied against principal according to management’s judgment as to the collectability of such principal. Loan origination fees and certain direct loan origination costs are being deferred and the net amount amortized as an adjustment of the related loan’s yield. Management is amortizing these amounts over the contractual life of the related loans. Allowance for Loan and Lease Losses The allowance for loan and lease losses represents the amount which management estimates is adequate to provide for probable loan losses inherent in the loan portfolio. The allowance method is used in providing for loan losses. Accordingly, all loan losses are charged to the allowance, and all recoveries are credited to it. The allowance for loan and lease losses is established through a provision for loan losses which is charged to operations. The provision is based on management’s periodic evaluation of the adequacy of the allowance for loan and lease losses, which encompasses the overall risk characteristics of the various portfolio segments, past experience with losses, the impact of economic conditions on borrowers, and other relevant factors. The estimates used in determining the adequacy of the allowance for loan and lease losses, including the amounts and timing of future cash flows expected on impaired loans, are particularly susceptible to significant change in the near term. A loan is considered impaired when it is probable the borrower will not repay the loan according to the original contractual terms of the loan agreement. Management has determined that first mortgage loans on one-to-four family properties and all consumer loans represent large groups of smaller-balance homogeneous loans that are to be collectively evaluated. Loans that experience insignificant payment delays, which are defined as 90 days or less, generally are not classified as impaired. A loan is not impaired during a period of delay in payment if the Company expects to collect all amounts due, including interest accrued, at the contractual interest rate for the period of delay. All loans identified as impaired are evaluated independently by management. The Company estimates credit losses on impaired loans based on the present value of expected cash flows or the fair value of the underlying collateral if the loan repayment is expected to come from the sale or operation of such collateral. Impaired loans, or portions thereof, are charged off when it is determined a realized loss has occurred. Until such time, an allowance for loan and lease losses is maintained for estimated losses. Cash receipts on impaired loans are applied first to accrued interest receivable unless otherwise required by the loan terms, except when an impaired loan is also a nonaccrual loan, in which case the portion of the payment related to interest is recognized as income. Mortgage loans secured by one-to-four family properties and all consumer loans are large groups of smaller-balance homogeneous loans and are measured for impairment collectively. Management determines the significance of payment delays on a case-by-case basis, taking into consideration all circumstances concerning the loan, the creditworthiness and payment history of the borrower, the length of the payment delay, and the amount of shortfall in relation to the principal and interest owed. Premises and Equipment Land is carried at cost. Premises and equipment are stated at cost net of accumulated depreciation. Depreciation is computed on the straight-line method over the estimated useful lives of the assets, which range from 3 to 20 years for furniture, fixtures, and equipment and 3 to 40 years for buildings and leasehold improvements. Expenditures for maintenance and repairs are charged against income as incurred. Costs of major additions and improvements are capitalized. Goodwill The Company accounts for goodwill using a three-step process for testing the impairment of goodwill on at least an annual basis. This approach could cause more volatility in the Company’s reported net income because impairment losses, if any, could occur irregularly and in varying amounts. No impairment of goodwill was recognized in any of the periods presented. Intangible Assets Intangible assets include core deposit intangibles, which are a measure of the value of consumer demand and savings deposits acquired in business combinations accounted for as purchases. The core deposit intangibles are being amortized to expense over a 10 year life on a straight-line basis. The recoverability of the carrying value of intangible assets is evaluated on an ongoing basis, and permanent declines in value, if any, are charged to expense. Bank-Owned Life Insurance (“BOLI”) The Company owns insurance on the lives of a certain group of key employees. The policies were purchased to help offset the increase in the costs of various fringe benefit plans including healthcare. The cash surrender value of these policies is included as an asset on the Consolidated Balance Sheet and any increases in the cash surrender value are recorded as noninterest income on the Consolidated Statement of Income. In the event of the death of an insured individual under these policies, the Company would receive a death benefit, which would be recorded as noninterest income. Other Real Estate Owned Real estate properties acquired through foreclosure are initially recorded at fair value at the date of foreclosure, establishing a new cost basis. After foreclosure, management periodically performs valuations and the real estate is carried at the lower of cost or fair value less estimated cost to sell. Revenue and expenses from operations of the properties, gains or losses on sales and additions to the valuation allowance are included in operating results. Income Taxes The Company and its subsidiaries file a consolidated federal income tax return. Deferred tax assets and liabilities are reflected at currently enacted income tax rates applicable to the period in which the deferred tax assets or liabilities are expected to be realized or settled. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes. Earnings Per Share The Company provides dual presentation of basic and diluted earnings per share. Basic earnings per share are calculated utilizing net income as reported in the numerator and average shares outstanding in the denominator. The computation of diluted earnings per share differs in that the dilutive effects of any stock options, warrants, and convertible securities are adjusted in the denominator. Stock-Based Compensation The Company accounts for stock compensation based on the grant date fair value of all share-based payment awards that are expected to vest, including employee share options to be recognized as employee compensation expense over the requisite service period. For each of the years ended December 31, 2015, 2014, and 2013, the Company recorded no compensation cost related to vested stock options. As of December 31, 2015, there was no unrecognized compensation cost related to unvested stock options. At year ended December 31, 2015, 585 shares of restricted stock were awarded and immediately vested. There were no shares of restricted stock issued in 2014 or 2013. For the years ended December 31, 2015 and 2014, 2,175 and 11,223 options were exercised resulting in net proceeds to the participant of $7,000 and $50,000, respectively. Cash Flow Information The Company has defined cash and cash equivalents as those amounts included in the Consolidated Balance Sheet captions as “Cash and due from banks” and “Federal funds sold” with original maturities of less than 90 days. Advertising Costs Advertising costs are expensed as incurred. Reclassification of Comparative Amounts Certain comparative amounts for prior years have been reclassified to conform to current-year presentations. Such reclassifications did not affect net income or retained earnings. Recent Accounting Pronouncements: In January 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-01, Investments – Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects. In January 2014, the FASB issued ASU 2014-04, Receivables – Troubled Debt Restructurings by Creditors (Subtopic 310-40): Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. . In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In June 2014, the FASB issued ASU 2014-11, Transfers and Servicing (Topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures In June 2014, the FASB issued ASU 2014-12, Compensation – Stock Compensation (Topic 718 ): Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period In August 2014, the FASB issued ASU 2014-14, Receivables – Troubled Debt Restructurings by Creditors (Subtopic 310-40) In November 2014, the FASB issued ASU 2014-17, Business Combinations (Topic 805): Pushdown Accounting. In February 2015, the FASB issued ASU 2015-02, Consolidation (Topic 810) In April 2015, the FASB issued ASU 2015-05, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40) In May 2015, the FASB issued ASU 2015-08 , Business Combinations – Pushdown Accounting – Amendment to SEC Paragraphs Pursuant to Staff Accounting Bulletin No. 115 In June 2015, the FASB issued ASU 2015-10, Technical Corrections and Improvements In August 2015, the FASB issued ASU 2015-14, Revenue from Contract with Customers Topic 606 In September 2015, the FASB issued ASU 2015-16, Business Combinations (Topic 805). In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities

Earnings Per Share _Text Block_

Earnings Per Share [Text Block]	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Earnings Per Share [Text Block]	NOTE 3 – EARNINGS PER SHARE The Company provides dual presentation of basic and diluted earnings per share. Basic earnings per share is calculated by dividing net income by the average shares outstanding. Diluted earnings per share adds the dilutive effects of stock options to average shares outstanding. The following table sets forth the composition of the weighted-average common shares (denominator) used in the basic and diluted earnings per share computation. For the Three For the Nine 2016 2015 2016 2015 Weighted-average common shares outstanding 2,633,752 2,253,584 2,445,821 2,248,468 Average treasury stock shares (386,165 ) (189,530 ) (386,165 ) (189,530 ) Weighted-average common shares and common stock equivalents used to calculate basic earnings per share 2,247,587 2,064,054 2,059,656 2,058,938 Additional common stock equivalents (stock options) used to calculate diluted earnings per share 8,643 8,585 8,876 9,254 Weighted-average common shares and common stock equivalents used to calculate diluted earnings per share 2,256,230 2,072,639 2,068,532 2,068,192 Options to purchase 31,949 shares of common stock, at prices ranging from $17.55 to $40.24, were outstanding during the three and nine months ended September 30, 2016. Of those options, 24,700 were considered dilutive for the three and nine month periods based on the market price exceeding the strike price. Options to purchase 42,437 shares of common stock, at prices ranging from $17.55 to $37.48, were outstanding during the three and nine months ended September 30, 2015. Of those options, 27,000 were considered dilutive for the three-month period based on the market price exceeding the strike price. For the nine months ended September 30, 2015, 27,250 options were considered dilutive.	2. EARNINGS PER SHARE There are no convertible securities that would affect the numerator in calculating basic and diluted earnings per share; therefore, net income as presented on the Consolidated Statement of Income will be used as the numerator. The following table sets forth the composition of the weighted-average common shares (denominator) used in the basic and diluted earnings per share computation for the year ended December 31. 2015 2014 2013 Weighted-average common shares outstanding 2,251,365 2,231,165 2,206,392 Average treasury stock shares (236,399 ) (189,530 ) (189,530 ) Weighted-average common shares and common stock equivalents used to calculate basic earnings per share 2,014,966 2,041,635 2,016,862 Additional common stock equivalents used to calculate diluted earnings per share 9,154 7,871 7,178 Weighted-average common shares and common stock equivalents used to calculate diluted earnings per share 2,024,120 2,049,506 2,024,040 Options to purchase 31,949 shares of common stock at prices ranging from $17.55 to $40.24 were outstanding during the year ended December 31, 2015. Of those options, 27,250 were considered dilutive based on the average market price exceeding the strike price for the year ended December 31, 2015. The remaining options had no dilutive effect on the earnings per share. Options to purchase 46,451 shares of common stock at prices ranging from $17.55 to $40.24 were outstanding during the year ended December 31, 2014. Of those options, 28,282 were considered dilutive based on the average market price exceeding the strike price for the year ended December 31, 2014. The remaining options had no dilutive effect on the earnings per share. Options to purchase 58,581 shares of common stock at prices ranging from $17.55 to $40.24 were outstanding during the year ended December 31, 2013. Of those options, 39,808 were considered dilutive based on the average market price exceeding the strike price for the year ended December 31, 2013. The remaining options had no dilutive effect on the earnings per share.

Investments in Debt and Marketa

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block]	NOTE 6 – INVESTMENT SECURITIES AVAILABLE FOR SALE The amortized cost and fair values of securities available for sale are as follows: September 30, 2016 (Dollar amounts in thousands) Amortized Gross Gross Fair Value U.S. government agency securities $ 10,516 $ 359 $ (12 ) $ 10,863 Obligations of states and political subdivisions: Taxable 1,616 186 — 1,802 Tax-exempt 81,829 3,899 (5 ) 85,723 Mortgage-backed securities in government-sponsored entities 20,939 485 (44 ) 21,380 Private-label mortgage-backed securities 1,927 141 — 2,068 Total debt securities 116,827 5,070 (61 ) 121,836 Equity securities in financial institutions 750 468 — 1,218 Total $ 117,577 $ 5,538 $ (61 ) $ 123,054 December 31, 2015 Amortized Gross Gross Fair Value U.S. government agency securities $ 21,655 $ 245 $ (271 ) $ 21,629 Obligations of states and political subdivisions: Taxable 1,989 134 — 2,123 Tax-exempt 91,940 3,402 (175 ) 95,167 Mortgage-backed securities in government-sponsored entities 24,480 316 (272 ) 24,524 Private-label mortgage-backed securities 2,079 184 — 2,263 Total debt securities 142,143 4,281 (718 ) 145,706 Equity securities in financial institutions 750 64 — 814 Total $ 142,893 $ 4,345 $ (718 ) $ 146,520 The amortized cost and fair value of debt securities at September 30, 2016, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (Dollar amounts in thousands) Amortized Fair Due in one year or less $ 2,842 $ 2,879 Due after one year through five years 9,132 9,500 Due after five years through ten years 12,916 13,510 Due after ten years 91,937 95,947 Total $ 116,827 $ 121,836 Proceeds from the sales of securities available for sale and the gross realized gains and losses for the three and nine months ended September 30 are as follows: For the Three Months For the Nine Months Ended (Dollar amounts in thousands) 2016 2015 2016 2015 Proceeds from sales $ — $ 11,973 $ 9,115 $ 15,284 Gross realized gains — 233 306 373 Gross realized losses — (22 ) (3 ) (116 ) Investment securities with an approximate carrying value of $64.7 million and $68.8 million at September 30, 2016 and December 31, 2015, respectively, were pledged to secure deposits and other purposes as required by law. The following tables show the Company’s gross unrealized losses and fair value, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position. September 30, 2016 Less than Twelve Months Total (Dollar amounts in thousands) Fair Gross Fair Gross Fair Gross U.S. government agency securities $ 2,000 $ — $ 1,465 $ (12 ) $ 3,465 $ (12 ) Obligations of states and political subdivisions Tax-exempt 608 — — (5 ) 608 (5 ) Mortgage-backed securities in government-sponsored entities — — 4,709 (44 ) 4,709 (44 ) Private-label mortgage-backed securities 75 — — — 75 — Total $ 2,683 $ — $ 6,174 $ (61 ) $ 8,857 $ (61 ) December 31, 2015 Less than Twelve Months Total Fair Gross Fair Gross Fair Gross U.S. government agency securities $ 3,818 $ (57 ) $ 10,872 $ (214 ) $ 14,690 $ (271 ) Obligations of states and political subdivisions Tax-exempt 1,268 (9 ) 9,394 (166 ) 10,662 (175 ) Mortgage-backed securities in government-sponsored entities 8,725 (86 ) 6,685 (186 ) 15,410 (272 ) Total $ 13,811 $ (152 ) $ 26,951 $ (566 ) $ 40,762 $ (718 ) There were 9 securities considered temporarily impaired at September 30, 2016. On a quarterly basis, the Company performs an assessment to determine whether there have been any events or economic circumstances indicating that a security with an unrealized loss has suffered other-than-temporary impairment (“OTTI”). A debt security is considered impaired if the fair value is less than its amortized cost basis at the reporting date. The Company assesses whether the unrealized loss is other than temporary. OTTI losses are recognized in earnings when the Company has the intent to sell the debt security or it is more likely than not that it will be required to sell the debt security before recovery of its amortized cost basis. However, even if the Company does not expect to sell a debt security, it must evaluate expected cash flows to be received and determine if a credit loss has occurred. An unrealized loss is generally deemed to be other than temporary and a credit loss is deemed to exist if the present value of the expected future cash flows is less than the amortized cost basis of the debt security. As a result the credit loss component of an OTTI is recorded as a component of investment securities gains (losses) in the accompanying Consolidated Statement of Income, while the remaining portion of the impairment loss is recognized in other comprehensive income, provided the Company does not intend to sell the underlying debt security and it is “more likely than not” that the Company will not have to sell the debt security prior to recovery. Debt securities issued by U.S. government agencies, U.S. government-sponsored enterprises, and state and political subdivisions accounted for more than 97% of the total available-for-sale portfolio as of September 30, 2016 and no credit losses are expected, given the explicit and implicit guarantees provided by the U.S. federal government and the lack of prolonged unrealized loss positions within the obligations of state and political subdivisions security portfolio. The Company considers the following factors in determining whether a credit loss exists and the period over which the debt security is expected to recover: • The length of time and the extent to which the fair value has been less than the amortized cost basis. • Changes in the near-term prospects of the underlying collateral of a security such as changes in default rates, loss severity given default and significant changes in prepayment assumptions; • The level of cash flows generated from the underlying collateral supporting the principal and interest payments of the debt securities; and • Any adverse change to the credit conditions and liquidity of the issuer, taking into consideration the latest information available about the overall financial condition of the issuer, credit ratings, recent legislation and government actions affecting the issuer’s industry and actions taken by the issuer to deal with the present economic climate. For the nine months ended September 30, 2016 and 2015, there were no available-for-sale debt securities with an unrealized loss that suffered OTTI. Management does not believe any individual unrealized loss as of September 30, 2016 or December 31, 2015 represented an other-than-temporary impairment. The unrealized losses on debt securities are primarily the result of interest rate changes. These conditions will not prohibit the Company from receiving its contractual principal and interest payments on these debt securities. The fair value of these debt securities is expected to recover as payments are received on these securities and they approach maturity. Should the impairment of any of these securities become other than temporary, the cost basis of the investment will be reduced and the resulting loss recognized in net income in the period the other-than-temporary impairment is identified.	3. INVESTMENT SECURITIES AVAILABLE FOR SALE The amortized cost and fair values of securities available for sale are as follows: December 31, 2015 (Dollar amounts in thousands) Amortized Gross Gross Fair Value U.S. government agency securities $ 21,655 $ 245 $ (271 ) $ 21,629 Obligations of states and political subdivisions: Taxable 1,989 134 — 2,123 Tax-exempt 91,940 3,402 (175 ) 95,167 Mortgage-backed securities in government-sponsored entities 24,480 316 (272 ) 24,524 Private-label mortgage-backed securities 2,079 184 — 2,263 Total debt securities 142,143 4,281 (718 ) 145,706 Equity securities in financial institutions 750 64 — 814 Total $ 142,893 $ 4,345 $ (718 ) $ 146,520 December 31, 2014 (Dollar amounts in thousands) Amortized Gross Gross Fair Value U.S. government agency securities $ 23,035 $ 311 $ (450 ) $ 22,896 Obligations of states and political subdivisions: Taxable 2,953 226 — 3,179 Tax-exempt 91,916 3,803 (553 ) 95,166 Mortgage-backed securities in government-sponsored entities 29,150 475 (234 ) 29,391 Private-label mortgage-backed securities 2,672 247 — 2,919 Total debt securities 149,726 5,062 (1,237 ) 153,551 Equity securities in financial institutions 750 33 — 783 Total $ 150,476 $ 5,095 $ (1,237 ) $ 154,334 The amortized cost and fair value of debt securities at December 31, 2015, by contractual maturity, are shown below. Expected maturities will differ from contractual maturities because borrowers may have the right to call or prepay obligations with or without call or prepayment penalties. (Dollar amounts in thousands) Amortized Fair Value Due in one year or less $ 1,135 $ 1,153 Due after one year through five years 10,790 10,890 Due after five years through ten years 19,172 19,830 Due after ten years 111,042 113,833 Total $ 142,139 $ 145,706 Investment securities with an approximate carrying value of $68.8 million and $61.9 million at December 31, 2015 and 2014, respectively, were pledged to secure deposits and other purposes as required by law. Proceeds from the sales of securities available for sale and the gross realized gains and losses for the years ended December, 31 are as follows (in thousands): 2015 2014 2013 Proceeds from sales $ 15,686 $ 8,383 $ 25,088 Gross realized gains 440 306 186 Gross realized losses (117 ) (58 ) (175 ) The following tables show the Company’s gross unrealized losses and fair value, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position. December 31, 2015 Less than Twelve Twelve Months or Total (Dollar amounts in thousands) Fair Gross Fair Gross Fair Gross U.S. government agency securities $ 3,818 $ (57 ) $ 10,872 $ (214 ) $ 14,690 $ (271 ) Obligations of states and political subdivisions Tax-exempt 1,268 (9 ) 9,394 (166 ) 10,662 (175 ) Mortgage-backed securities in government-sponsored entities 8,725 (86 ) 6,685 (186 ) 15,410 (272 ) Total $ 13,811 $ (152 ) $ 26,951 $ (566 ) $ 40,762 $ (718 ) December 31, 2014 Less than Twelve Twelve Months or Total (Dollar amounts in thousands) Fair Gross Fair Gross Fair Gross U.S. government agency securities $ — $ — $ 15,734 $ (450 ) $ 15,734 $ (450 ) Obligations of states and political subdivisions Tax-exempt 2,406 (10 ) 18,232 (543 ) 20,638 (553 ) Mortgage-backed securities in government-sponsored entities — — 16,774 (234 ) 16,774 (234 ) Total $ 2,406 $ (10 ) $ 50,740 $ (1,227 ) $ 53,146 $ (1,237 ) There were 46 securities that were considered temporarily impaired at December 31, 2015. On a quarterly basis, the Company performs an assessment to determine whether there have been any events or economic circumstances indicating that a security with an unrealized loss has suffered other-than-temporary impairment (“OTTI”). A debt security is considered impaired if the fair value is less than its amortized cost basis at the reporting date. The accounting literature requires the Company to assess whether the unrealized loss is other than temporary. For equity securities where the fair value has been significantly below cost for one year, the Company’s policy is to recognize an impairment loss unless sufficient evidence is available that the decline is not other than temporary and a recovery period can be predicted. The Company has asserted that at December 31, 2015 and 2014, the declines outlined in the above table represent temporary declines and the Company does not intend to sell and does not believe it will be required to sell these securities before recovery of their cost basis, which may be at maturity. The Company has concluded that any impairment of its investment securities portfolio outlined in the above table is not other than temporary and is the result of interest rate changes, sector credit rating changes, or company-specific rating changes that are not expected to result in the non-collection of principal and interest during the period. Debt securities issued by U.S. government agencies, U.S. government-sponsored enterprises, and state and political subdivisions accounted for more than 97.9% of the total available-for-sale portfolio as of December 31, 2015, and no credit losses are expected, given the explicit and implicit guarantees provided by the U.S. federal government and the lack of significant unrealized loss positions within the obligations of state and political subdivisions security portfolio. The Company evaluates credit losses on a quarterly basis. The Company considered the following factors in determining whether a credit loss exists and the period over which the debt security is expected to recover: • The length of time and the extent to which the fair value has been less than the amortized cost basis. • Changes in the near-term prospects of the underlying collateral of a security such as changes in default rates, loss severity given default and significant changes in prepayment assumptions. • The level of cash flows generated from the underlying collateral supporting the principal and interest payments of the debt securities. • Any adverse change to the credit conditions and liquidity of the issuer, taking into consideration the latest information available about the overall financial condition of the issuer, credit ratings, recent legislation, and government actions affecting the issuer’s industry and actions taken by the issuer to deal with the present economic climate.

Loans, Notes, Trade and Other R

Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Loans, Notes, Trade and Other Receivables Disclosure [Text Block]	NOTE 7 – LOANS AND RELATED ALLOWANCE FOR LOAN AND LEASE LOSSES Major classifications of loans are summarized as follows (in thousands): September 30, December 31, Commercial and industrial $ 59,376 $ 42,536 Real estate – construction 17,633 22,137 Real estate – mortgage: Residential 258,952 232,478 Commercial 245,636 231,701 Consumer installment 4,732 4,858 586,329 533,710 Less: Allowance for loan and lease losses 6,334 6,385 Net loans $ 579,995 $ 527,325 The Company’s primary business activity is with customers located within its local Northeastern Ohio trade area, eastern Geauga County, and contiguous counties to the north, east, and south. The Company also serves the central Ohio market with offices in Dublin, Sunbury and Westerville, Ohio. Commercial, residential, consumer, and agricultural loans are granted. Although the Company has a diversified loan portfolio, loans outstanding to individuals and businesses are dependent upon the local economic conditions in the Company’s immediate trade area. Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff generally are reported at their outstanding unpaid principal balances net of the allowance for loan and lease losses. Interest income is recognized as income when earned on the accrual method. The accrual of interest is discontinued on a loan when management believes, after considering economic and business conditions, the borrower’s financial condition is such that collection of interest is doubtful. Interest received on nonaccrual loans is recorded as income or applied against principal according to management’s judgment as to the collectability of such principal. Loan origination fees and certain direct loan origination costs are being deferred and the net amount amortized as an adjustment of the related loan’s yield. Management is amortizing these amounts over the contractual life of the related loans. The following tables summarize the primary segments of the loan portfolio and allowance for loan and lease losses (in thousands): Real Estate- Mortgage September 30, 2016 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 844 $ 1,093 $ 3,238 $ 6,466 $ 5 $ 11,646 Collectively evaluated for impairment 58,532 16,540 255,714 239,170 4,727 574,683 Total loans $ 59,376 $ 17,633 $ 258,952 $ 245,636 $ 4,732 $ 586,329 Real estate- Mortgage December 31, 2015 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 1,808 $ 1,787 $ 3,881 $ 6,199 $ 6 $ 13,681 Collectively evaluated for impairment 40,728 20,350 228,597 225,502 4,852 520,029 Total loans $ 42,536 $ 22,137 $ 232,478 $ 231,701 $ 4,858 $ 533,710 Real Estate- Mortgage September 30, 2016 Commercial Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 184 $ 17 $ 104 $ 239 $ — 544 Collectively evaluated for impairment 329 121 2,657 2,656 27 5,790 Total ending allowance balance $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Real Estate- Mortgage December 31, 2015 Commercial Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 388 $ 130 $ 276 $ 39 $ — $ 833 Collectively evaluated for impairment 479 146 2,863 2,039 25 5,552 Total ending allowance balance $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 The Company’s loan portfolio is segmented to a level that allows management to monitor risk and performance. The portfolio is segmented into Commercial and Industrial (“C&I”), Real Estate Construction, Real Estate—Mortgage which is further segmented into Residential and Commercial real estate (“CRE”), and Consumer Installment Loans. The C&I loan segment consists of loans made for the purpose of financing the activities of commercial customers. The residential mortgage loan segment consists of loans made for the purpose of financing the activities of residential homeowners. The commercial mortgage loan segment consists of loans made for the purpose of financing the activities of commercial real estate owners and operators. The consumer loan segment consists primarily of installment loans and overdraft lines of credit connected with customer deposit accounts. The decrease in the allowance for loan loss for C&I and Residential real estate loan portfolios were offset by increases in the allowance for the CRE loan portfolio. Management evaluates individual loans in all of the commercial segments for possible impairment based on guidance established by the Board of Directors. Loans are considered to be impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in evaluating impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. The Company does not separately evaluate individual consumer and residential mortgage loans for impairment, unless such loans are part of a larger relationship that is impaired. Once the determination has been made that a loan is impaired, the determination of whether a specific allocation of the allowance is necessary is measured by comparing the recorded investment in the loan to the fair value of the loan using one of the following methods: (a) the present value of expected future cash flows discounted at the loan’s effective interest rate; (b) the loan’s observable market price; or (c) the fair value of the collateral less selling costs. The method is selected on a loan-by-loan basis, with management primarily utilizing the fair value of collateral method. The evaluation of the need and amount of a specific allocation of the allowance and whether a loan can be removed from impairment status is made on a quarterly basis. The Company’s policy for recognizing interest income on impaired loans does not differ from its overall policy for interest recognition. The following tables present impaired loans by class, segregated by those for which a specific allowance was required and those for which a specific allowance was not necessary (in thousands): September 30, 2016 Impaired Loans Recorded Unpaid Related With no related allowance recorded: Commercial and industrial $ 569 $ 569 $ — Real estate – construction 1,076 1,076 — Real estate – mortgage: Residential 2,774 2,771 — Commercial 1,378 1,375 — Consumer installment 5 5 — Total $ 5,802 $ 5,796 $ — With an allowance recorded: Commercial and industrial $ 275 $ 275 $ 184 Real estate – construction 17 17 17 Real estate – mortgage: Residential 464 462 104 Commercial 5,088 5,078 239 Consumer installment — — — Total $ 5,844 $ 5,832 $ 544 Total: Commercial and industrial $ 844 $ 844 $ 184 Real estate – construction 1,093 1,093 17 Real estate – mortgage: Residential 3,238 3,233 104 Commercial 6,466 6,453 239 Consumer installment 5 5 — Total $ 11,646 $ 11,628 $ 544 December 31, 2015 Impaired Loans Recorded Unpaid Related With no related allowance recorded: Commercial and industrial $ 1,027 $ 1,025 $ — Real estate – construction 1,657 1,651 — Real estate – mortgage: Residential 2,445 2,443 — Commercial 2,337 2,335 — Consumer installment 6 6 — Total $ 7,472 $ 7,460 $ — With an allowance recorded: Commercial and industrial $ 781 $ 781 $ 388 Real estate – construction 130 130 130 Real estate – mortgage: Residential 1,436 1,436 276 Commercial 3,862 3,846 39 Consumer installment — — — Total $ 6,209 $ 6,193 $ 833 Total: Commercial and industrial $ 1,808 $ 1,806 $ 388 Real estate – construction 1,787 1,781 130 Real estate – mortgage: Residential 3,881 3,879 276 Commercial 6,199 6,181 39 Consumer installment 6 6 — Total $ 13,681 $ 13,653 $ 833 The following tables present interest income by class, recognized on impaired loans (in thousands): For the Three Months Ended For the Nine Months Ended Average Interest Average Interest Total: Commercial and industrial $ 864 $ 4 $ 1,218 $ 9 Real estate – construction 1,105 3 1,404 22 Real estate – mortgage: Residential 3,389 36 3,660 36 Commercial 7,939 8 7,449 115 Consumer installment 5 — 6 — $ 13,302 $ 51 $ 13,737 $ 182 For the Three Months For the Nine Months Ended Average Interest Average Interest Total: Commercial and industrial $ 1,480 $ 21 $ 1,354 $ 73 Real estate – construction 2,347 28 2,614 94 Real estate – mortgage: Residential 4,195 43 4,514 128 Commercial 5,476 71 4,871 200 Consumer installment 6 — 6 — $ 13,504 $ 163 $ 13,359 $ 495 Management uses a nine-point internal risk-rating system to monitor the credit quality of the overall loan portfolio. The first five categories are considered not criticized and are aggregated as Pass rated. The criticized rating categories utilized by management generally follow bank regulatory definitions. The Special Mention category includes assets that are currently protected but are potentially weak, resulting in an undue and unwarranted credit risk, but not to the point of justifying a Substandard classification. Loans in the Substandard category have well-defined weaknesses that jeopardize the liquidation of the debt and have a distinct possibility that some loss will be sustained if the weaknesses are not corrected. All loans greater than 90 days past due are considered Substandard. Any portion of a loan that has been charged off is placed in the Loss category. To help ensure that risk ratings are accurate and reflect the present and future capacity of borrowers to repay a loan as agreed, the Company has a structured loan-rating process with several layers of internal and external oversight. Generally, consumer and residential mortgage loans are included in the Pass categories unless a specific action, such as bankruptcy, repossession, or death, occurs to raise awareness of a possible credit event. The Company’s Commercial Loan Officers are responsible for the timely and accurate risk rating of the loans in their portfolios at origination and on an ongoing basis with the Chief Credit Officer ultimately responsible for accurate and timely risk ratings. The Credit Department performs an annual review of all commercial relationships with loan balances of $1,000,000 or greater. Confirmation of the appropriate risk grade is included in the review on an ongoing basis. The Company engages an external consultant to conduct loan reviews on a semiannual basis. Generally, the external consultant reviews commercial relationships greater than $250,000 and/or criticized relationships greater than $125,000. Detailed reviews, including plans for resolution, are performed on loans classified as Substandard on a quarterly basis. Loans in the Special Mention and Substandard categories that are collectively evaluated for impairment are given separate consideration in the determination of the allowance. The primary risk of commercial and industrial loans is the current economic uncertainties. C&I loans are, by nature, secured by less substantial collateral than real estate-secured loans. The primary risk of real estate construction loans is potential delays and /or disputes during the completion process. The primary risk of residential real estate loans is current economic uncertainties along with the slow recovery in the housing market. The primary risk of commercial real estate loans is loss of income of the owner or occupier of the property and the inability of the market to sustain rent levels. Consumer installment loans historically have experienced higher delinquency rates. Consumer installments are typically secured by less substantial collateral than other types of credits. The following tables present the classes of the loan portfolio summarized by the aggregate Pass and the criticized categories of Special Mention, Substandard and Doubtful within the internal risk-rating system (in thousands): Pass Special Substandard Doubtful Total September 30, 2016 Commercial and industrial $ 57,954 $ 445 $ 977 $ — $ 59,376 Real estate – construction 17,448 144 24 17 17,633 Real estate – mortgage: Residential 252,783 433 5,736 — 258,952 Commercial 237,916 3,141 4,579 — 245,636 Consumer installment 4,723 — 9 — 4,732 Total $ 570,824 $ 4,163 $ 11,325 $ 17 $ 586,329 Pass Special Substandard Doubtful Total December 31, 2015 Commercial and industrial $ 40,560 $ 242 $ 1,734 $ — $ 42,536 Real estate – construction 22,007 — — 130 22,137 Real estate – mortgage: Residential 225,945 728 5,805 — 232,478 Commercial 219,331 4,327 8,043 — 231,701 Consumer installment 4,854 — 4 — 4,858 Total $ 512,697 $ 5,297 $ 15,586 $ 130 $ 533,710 Management further monitors the performance and credit quality of the loan portfolio by analyzing the age of the portfolio as determined by the length of time a recorded payment is past due. Nonperforming assets include nonaccrual loans, troubled debt restructurings (TDRs), loans 90 days or more past due, EMORECO assets, other real estate owned, and repossessed assets. A loan is classified as nonaccrual when, in the opinion of management, there are serious doubts about collectability of interest and principal. Accrual of interest is discontinued on a loan when management believes, after considering economic and business conditions, the borrower’s financial condition is such that collection of principal and interest is doubtful. Payments received on nonaccrual loans are applied against the principal balance. The following tables present the classes of the loan portfolio summarized by the aging categories of performing loans (in thousands): Current 30-59 Days 60-89 Days 90 Days+ Total Total September 30, 2016 Commercial and industrial $ 58,889 $ 59 $ 92 $ 336 $ 487 $ 59,376 Real estate – construction 17,633 — — — — 17,633 Real estate – mortgage: Residential 257,068 1,052 547 285 1,884 258,952 Commercial 244,771 121 — 744 865 245,636 Consumer installment 4,656 76 — — 76 4,732 Total $ 583,017 $ 1,308 $ 639 $ 1,365 $ 3,312 $ 586,329 Current 30-59 Days 60-89 Days 90 Days+ Total Total December 31, 2015 Commercial and industrial $ 41,544 $ 225 $ 26 $ 741 $ 992 $ 42,536 Real estate – construction 22,137 — — — — 22,137 Real estate – mortgage: Residential 229,725 1,482 92 1,179 2,753 232,478 Commercial 230,903 189 — 609 798 231,701 Consumer installment 4,837 16 3 2 21 4,858 Total $ 529,146 $ 1,912 $ 121 $ 2,531 $ 4,564 $ 533,710 The following tables present the classes of the loan portfolio summarized by nonaccrual loans (in thousands): September 30, 2016 90+Days Past Due Commercial and industrial $ 920 $ — Real estate – construction 17 — Real estate – mortgage: Residential 3,822 — Commercial 1,730 — Consumer installment — — Total $ 6,490 $ — December 31, 2015 90+Days Past Due Commercial and industrial $ 1,450 $ — Real estate – construction 130 — Real estate – mortgage: Residential 4,122 — Commercial 1,842 — Consumer installment 1 2 Total $ 7,545 $ 2 An allowance for loan and lease losses (“ALLL”) is maintained to absorb losses from the loan portfolio. The ALLL is based on management’s continuing evaluation of the risk characteristics and credit quality of the loan portfolio, assessment of current economic conditions, diversification and size of the portfolio, adequacy of collateral, past and anticipated loss experience, and the amount of nonperforming loans. The Company’s methodology for determining the ALLL is based on the requirements of ASC Section 310-10-35 for loans individually evaluated for impairment (discussed above) and ASC Subtopic 450-20 for loans collectively evaluated for impairment, as well as the Interagency Policy Statements on the Allowance for Loan and Lease Losses and other bank regulatory guidance. The total of the two components represents the Company’s ALLL. Management also performs impairment analyses on TDRs, which may result in specific reserves. Loans that are collectively evaluated for impairment are analyzed with general allowances being made as appropriate. For general allowances, historical loss trends are used in the estimation of losses in the current portfolio. These historical loss amounts are modified by other qualitative factors. The classes described above, which are based on the purpose code assigned to each loan, provide the starting point for the ALLL analysis. Management tracks the historical net charge-off activity at the purpose code level. A historical charge-off factor is calculated using the last four consecutive historical quarters. Management has identified a number of additional qualitative factors which it uses to supplement the historical charge-off factor because these factors are likely to cause estimated credit losses associated with the existing loan pools to differ from historical loss experience. The additional factors that are evaluated quarterly and updated using information obtained from internal, regulatory, and governmental sources are: national and local economic trends and conditions; levels of and trends in delinquency rates and nonaccrual loans; trends in volumes and terms of loans; effects of changes in lending policies; experience, ability, and depth of lending staff; value of underlying collateral; and concentrations of credit from a loan type, industry and/or geographic standpoint. Management reviews the loan portfolio on a quarterly basis using a defined, consistently applied process in order to make appropriate and timely adjustments to the ALLL. When information confirms all or part of specific loans to be uncollectible, these amounts are promptly charged off against the ALLL. The following tables summarize the primary segments of the loan portfolio (in thousands): Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at December 31, 2015 $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Charge-offs (197 ) — (394 ) (70 ) (18 ) (679 ) Recoveries 51 — 113 140 9 313 Provision (208 ) (138 ) (97 ) 747 11 315 ALLL balance at September 30, 2016 $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at December 31, 2014 $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Charge-offs (196 ) (385 ) (425 ) (92 ) (11 ) (1,109 ) Recoveries 186 — 161 5 21 373 Provision (54 ) (149 ) (13 ) 450 (24 ) 210 ALLL balance at September 30, 2015 $ 578 $ 334 $ 3,426 $ 1,939 $ 43 $ 6,320 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at June 30, 2016 $ 484 $ 159 $ 2,788 $ 2,909 $ 26 $ 6,366 Charge-offs (74 ) — (149 ) — (3 ) (226 ) Recoveries 4 — 82 — 3 89 Provision 99 (21 ) 40 (14 ) 1 105 ALLL balance at September 30, 2016 $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at June 30, 2015 $ 610 $ 363 $ 3,347 $ 1,978 $ 48 $ 6,346 Charge-offs (100 ) — (124 ) (5 ) — (229 ) Recoveries 5 — 81 5 7 98 Provision 63 (29 ) 122 (39 ) (12 ) 105 ALLL balance at September 30, 2015 $ 578 $ 334 $ 3,426 $ 1,939 $ 43 $ 6,320 For the three months ended September 30, 2016 there were no troubled debt restructurings. The following tables summarize troubled debt restructurings (in thousands): For the Nine Months Ended September 30, 2016 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 2 — 2 $ 169 $ 169 Residential real estate 1 — 1 58 58 Commercial real estate 1 — 1 311 311 Consumer — — — — — For the Three Months Ended September 30, 2015 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 2 — 2 $ 15 $ 15 Real estate construction — — — — — Residential real estate 1 — 1 164 164 Consumer 1 — 1 9 9 For the Nine Months Ended September 30, 2015 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 3 1 4 $ 126 $ 126 Real estate construction 1 — 1 181 181 Residential real estate 2 1 3 398 418 Consumer 1 — 1 9 9 The following tables summarize subsequent defaults of troubled debt restructurings (in thousands): For the Three Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 1 $ 3 Residential real estate 1 58 For the Nine Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 2 $ 273 Real estate construction 1 58 For the Three Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 1 $ 8 Real estate construction — — Consumer 1 8 For the Nine Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 3 $ 55 Real estate construction 1 152 Consumer 1 8	4. LOANS AND RELATED ALLOWANCE FOR LOAN LOSSES Major classifications of loans at December 31 are summarized as follows (in thousands): 2015 2014 Commercial and industrial $ 42,536 $ 34,928 Real estate – construction 22,137 30,296 Real estate – mortgage: Residential 232,478 210,096 Commercial 231,701 190,685 Consumer installment 4,858 4,579 533,710 470,584 Less allowance for loan and lease losses (6,385 ) (6,846 ) Net loans $ 527,325 $ 463,738 The Company’s primary business activity is with customers located within its local trade area, eastern Geauga County, and contiguous counties to the north, east, and south. The Company also serves the central Ohio market with offices in Dublin and Westerville, Ohio. Commercial, residential, consumer, and agricultural loans are granted. Although the Company has a diversified loan portfolio at December 31, 2015 and 2014, loans outstanding to individuals and businesses are dependent upon the local economic conditions in its immediate trade area. The following tables summarize the primary segments of the loan portfolio and the allowance for loan and lease losses as of December 31, 2015 and 2014 (in thousands): Real Estate- Mortgage December 31, 2015 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 1,808 $ 1,787 $ 3,881 $ 6,199 $ 6 $ 13,681 Collectively evaluated for impairment 40,728 20,350 228,597 225,502 4,852 520,029 Total loans $ 42,536 $ 22,137 $ 232,478 $ 231,701 $ 4,858 $ 533,710 Real estate- Mortgage December 31, 2014 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 1,393 $ 3,296 $ 5,183 $ 4,490 $ 6 $ 14,368 Collectively evaluated for impairment 33,535 27,000 204,913 186,195 4,573 456,216 Total loans $ 34,928 $ 30,296 $ 210,096 $ 190,685 $ 4,579 $ 470,584 Real Estate- Mortgage December 31, 2015 Commercial and Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 388 $ 130 $ 276 $ 39 $ — $ 833 Collectively evaluated for impairment 479 146 2,863 2,039 25 5,552 Total ending allowance balance $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Real Estate- Mortgage December 31, 2014 Commercial and Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 83 $ 589 $ 892 $ 30 $ 2 $ 1,596 Collectively evaluated for impairment 559 279 2,811 1,546 55 5,250 Total ending allowance balance $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 The Company’s loan portfolio is segmented to a level that allows management to monitor risk and performance. The portfolio is segmented into Commercial and Industrial (“C&I”), Real Estate Construction, Real Estate—Mortgage which is further segmented into Residential and Commercial real estate, and Consumer Installment Loans. The C&I loan segment consists of loans made for the purpose of financing the activities of commercial customers. The residential mortgage loan segment consists of loans made for the purpose of financing the activities of residential homeowners. The commercial mortgage loan segment consists of loans made for the purpose of financing the activities of commercial real estate owners and operators. The consumer loan segment consists primarily of installment loans and overdraft lines of credit connected with customer deposit accounts. Management evaluates individual loans in all of the commercial segments for possible impairment if the loan is greater than $150,000 and if the loan either is in nonaccrual status, or is risk rated Substandard or Doubtful and is greater than 90 days past due. Loans are considered to be impaired when, based on current information and events, it is probable that the Company will be unable to collect the scheduled payments of principal or interest when due according to the contractual terms of the loan agreement. Factors considered by management in evaluating impairment include payment status, collateral value, and the probability of collecting scheduled principal and interest payments when due. Management determines the significance of payment delays and payment shortfalls on a case-by-case basis, taking into consideration all of the circumstances surrounding the loan and the borrower, including the length of the delay, the reasons for the delay, the borrower’s prior payment record, and the amount of the shortfall in relation to the principal and interest owed. The Company does not separately evaluate individual consumer and residential mortgage loans for impairment, unless such loans are part of a larger relationship that is impaired. Once the determination has been made that a loan is impaired, the determination of whether a specific allocation of the allowance is necessary is measured by comparing the recorded investment in the loan to the fair value of the loan using one of three methods: (a) the present value of expected future cash flows discounted at the loan’s effective interest rate; (b) the loan’s observable market price; or (c) the fair value of the collateral less selling costs. The method is selected on a loan-by-loan basis, with management primarily utilizing the fair value of collateral method. The evaluation of the need and amount of a specific allocation of the allowance and whether a loan can be removed from impairment status is made on a quarterly basis. The Company’s policy for recognizing interest income on impaired loans does not differ from its overall policy for interest recognition. The following tables present impaired loans by class, segregated by those for which a specific allowance was required and those for which a specific allowance was not necessary (in thousands): December 31, 2015 Impaired Loans Recorded Unpaid Principal Related With no related allowance recorded: Commercial and industrial $ 1,027 $ 1,025 $ — Real estate – construction 1,657 1,651 — Real estate – mortgage: Residential 2,445 2,443 — Commercial 2,337 2,335 — Total $ 7,466 $ 7,454 $ — With an allowance recorded: Commercial and industrial $ 781 $ 781 $ 388 Real estate – construction 130 130 130 Real estate – mortgage: Residential 1,436 1,436 276 Commercial 3,862 3,846 39 Consumer installment 6 6 — Total $ 6,215 $ 6,199 $ 833 Total: Commercial and industrial $ 1,808 $ 1,806 $ 388 Real estate – construction 1,787 1,781 130 Real estate – mortgage: Residential 3,881 3,879 276 Commercial 6,199 6,181 39 Consumer installment 6 6 — Total $ 13,681 $ 13,653 $ 833 December 31, 2014 Impaired Loans Recorded Unpaid Principal Related With no related allowance recorded: Commercial and industrial $ 1,146 $ 1,145 $ — Real estate – construction 2,707 2,705 — Real estate – mortgage: Residential 2,202 2,197 — Commercial 4,064 4,060 — Total $ 10,119 $ 10,107 $ — With an allowance recorded: Commercial and industrial $ 247 $ 247 $ 83 Real estate – construction 589 589 589 Real estate – mortgage: Residential 2,981 2,978 892 Commercial 426 426 30 Consumer installment 6 6 2 Total $ 4,249 $ 4,246 $ 1,596 Total: Commercial and industrial $ 1,393 $ 1,392 $ 83 Real estate – construction 3,296 3,294 589 Real estate – mortgage: Residential 5,183 5,175 892 Commercial 4,490 4,486 30 Consumer installment 6 6 2 Total $ 14,368 $ 14,353 $ 1,596 The tables above include troubled debt restructuring totaling $3.1 million and $2.9 million as of December 31, 2015 and 2014, respectively. The following table presents interest income by class, recognized on impaired loans (in thousands): As of December 31, 2015 As of December 31, 2014 As of December 31, 2013 Average Interest Average Interest Average Interest Commercial and industrial $ 1,468 $ 100 $ 1,989 $ 85 $ 2,187 $ 119 Real estate – construction 2,407 115 3,631 154 3,743 183 Real estate – mortgage: Residential 4,356 160 5,331 171 5,380 293 Commercial 5,203 350 5,998 229 6,500 493 Consumer installment 6 — 11 1 13 1 Total $ 13,440 $ 725 $ 16,960 $ 640 $ 17,824 $ 1,090 Troubled Debt Restructuring (TDR) describes loans on which the bank has granted concessions for reasons related to the customer’s financial difficulties. Such concessions may include one or more of the following: • reduction in the interest rate to below market rates • extension of repayment requirements beyond normal terms • reduction of the principal amount owed • reduction of accrued interest due • acceptance of other assets in full or partial payment of a debt In each case the concession is made due to deterioration in the borrower’s financial condition, and the new terms are less stringent than those required on a new loan with similar risk. The following tables present the number of loan modifications by class, the corresponding recorded investment, and the subsequently defaulted modifications (in thousands): December 31, 2015 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 6 — 6 $ 434 $ 434 Real estate construction 1 — 1 181 181 Residential real estate 5 1 6 515 535 Commercial real estate 1 — 1 270 270 December 31, 2015 Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 2 $ 14 Real estate construction 1 130 December 31, 2014 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Residential real estate 3 — 3 $ 140 $ 140 Commercial real estate 1 — 1 48 48 Consumer 1 — 1 6 6 December 31, 2014 Troubled Debt Restructurings subsequently defaulted Number of Recorded Residential real estate 1 $ 15 December 31, 2013 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 6 1 7 $ 1,264 $ 1,264 Residential real estate 7 — 7 784 784 Commercial real estate 2 — 2 834 834 December 31, 2013 Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 5 $ 574 Commercial real estate 1 190 Management uses a nine-point internal risk-rating system to monitor the credit quality of the overall loan portfolio. The first five categories are considered not criticized and are aggregated as Pass-rated. The criticized rating categories utilized by management generally follow bank regulatory definitions. The Special Mention category includes assets that are currently protected but are potentially weak, resulting in an undue and unwarranted credit risk, but not to the point of justifying a Substandard classification. Loans in the Substandard category have well-defined weaknesses that jeopardize the liquidation of the debt and have a distinct possibility that some loss will be sustained if the weaknesses are not corrected. All loans greater than 90 days past due are considered Substandard. Any portion of a loan that has been charged off is placed in the Loss category. To help ensure that risk ratings are accurate and reflect the present and future capacity of borrowers to repay a loan as agreed, the Company has a structured loan-rating process with several layers of internal and external oversight. Generally, consumer and residential mortgage loans are included in the Pass categories unless a specific action, such as bankruptcy, repossession, or death, occurs to raise awareness of a possible credit event. The Company’s Commercial Loan Officers are responsible for the timely and accurate risk rating of the loans in their portfolios at origination and on an ongoing basis with the Chief Credit Officer ultimately responsible for accurate and timely risk ratings. The Credit Department performs an annual review of all commercial relationships $1,000,000 or greater. Confirmation of the appropriate risk grade is included in the review on an ongoing basis. The Company engages an external consultant to conduct loan reviews on a semiannual basis. Generally, the external consultant reviews commercial relationships greater than $250,000 and/or criticized relationships greater than $125,000. Detailed reviews, including plans for resolution, are performed on loans classified as Substandard on a quarterly basis. Loans in the Special Mention and Substandard categories that are collectively evaluated for impairment are given separate consideration in the determination of the allowance. The following tables present the classes of the loan portfolio summarized by the aggregate Pass rating and the criticized categories of Special Mention, Substandard, and Doubtful within the internal risk rating system as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Pass Special Substandard Doubtful Total Commercial and industrial $ 40,560 $ 242 $ 1,734 $ — $ 42,536 Real estate – construction 22,007 — — 130 22,137 Real estate – mortgage: Residential 225,945 728 5,805 — 232,478 Commercial 219,331 4,327 8,043 — 231,701 Consumer installment 4,854 — 4 — 4,858 Total $ 512,697 $ 5,297 $ 15,586 $ 130 $ 533,710 December 31, 2014 Pass Special Substandard Doubtful Total Commercial and industrial $ 33,160 $ — $ 1,730 $ 38 $ 34,928 Real estate – construction 29,212 495 — 589 30,296 Real estate – mortgage: Residential 200,928 584 8,584 — 210,096 Commercial 180,899 3,908 5,878 — 190,685 Consumer installment 4,572 — 7 — 4,579 Total $ 448,759 $ 4,987 $ 16,211 $ 627 $ 470,584 Management further monitors the performance and credit quality of the loan portfolio by analyzing the age of the portfolio as determined by the length of time a recorded payment is past due. The following tables present the classes of the loan portfolio summarized by the aging categories of loans and nonaccrual loans as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Current 30-59 Days 60-89 Days 90 Days+ Total Total Commercial and industrial $ 41,544 $ 225 $ 26 $ 741 $ 992 $ 42,536 Real estate – construction 22,137 — — — — 22,137 Real estate – mortgage: Residential 229,725 1,482 92 1,179 2,753 232,478 Commercial 230,903 189 — 609 798 231,701 Consumer installment 4,837 16 3 2 21 4,858 Total $ 529,146 $ 1,912 $ 121 $ 2,531 $ 4,564 $ 533,710 December 31, 2014 Current 30-59 Days 60-89 Days 90 Days+ Total Total Commercial and industrial $ 34,480 $ 349 $ 68 $ 31 $ 448 $ 34,928 Real estate – construction 30,296 — — — — 30,296 Real estate – mortgage: Residential 205,753 2,065 363 1,915 4,343 210,096 Commercial 190,088 30 — 567 597 190,685 Consumer installment 4,547 27 3 2 32 4,579 Total $ 465,164 $ 2,471 $ 434 $ 2,515 $ 5,420 $ 470,584 The following tables present the classes of the loan portfolio summarized by nonaccrual loans and loans 90 days or more past due and still accruing as of December 31, 2015 and 2014 (in thousands): December 31, 2015 Nonaccrual 90+ Day Past Commercial and industrial $ 1,450 $ — Real estate – construction 130 — Real estate – mortgage: Residential 4,122 — Commercial 1,842 — Consumer installment 1 2 Total $ 7,545 $ 2 December 31, 2014 Nonaccrual 90+ Days Past Commercial and industrial $ 365 $ — Real estate – construction 587 — Real estate – mortgage: Residential 5,310 165 Commercial 1,083 — Consumer installment 2 — Total $ 7,347 $ 165 Interest income that would have been recorded had these loans not been placed on nonaccrual status was $259,000 in 2015, $207,000 in 2014, and $439,000 in 2013. An allowance for loan and lease losses (“ALLL”) is maintained to absorb losses from the loan portfolio. The ALLL is based on management’s continuing evaluation of the risk characteristics and credit quality of the loan portfolio, assessment of current economic conditions, diversification and size of the portfolio, adequacy of collateral, past and anticipated loss experience, and the amount of nonperforming loans. The Company’s methodology for determining the ALLL is based on the requirements of ASC Section 310-10-35 for loans individually evaluated for impairment (discussed above) and ASC Subtopic 450-20 for loans collectively evaluated for impairment, as well as the Interagency Policy Statement on the Allowance for Loan and Lease Losses and other bank regulatory guidance. The total of the two components represents the Company’s ALLL. Loans that are collectively evaluated for impairment are analyzed, with general allowances being made as appropriate. For general allowances, historical loss trends are used in the estimation of losses in the current portfolio. These historical loss amounts are modified by other qualitative factors. The classes described above, which are based on the purpose code assigned to each loan, provide the starting point for the ALLL analysis. Management tracks the historical net charge-off activity at the purpose code level. A historical charge-off factor is calculated utilizing the last twelve consecutive quarters. Management has identified a number of additional qualitative factors which it uses to supplement the historical charge-off factor, because these factors are likely to cause estimated credit losses associated with the existing loan pools to differ from historical loss experience. The additional factors that are evaluated quarterly and updated using information obtained from internal, regulatory, and governmental sources are: national and local economic trends and conditions; levels of and trends in delinquency rates and nonaccrual loans; trends in volumes and terms of loans; effects of changes in lending policies; experience, ability, and depth of lending staff; value of underlying collateral; and concentrations of credit from a loan type, industry, and/or geographic standpoint. Management reviews the loan portfolio on a quarterly basis using a defined, consistently applied process in order to make appropriate and timely adjustments to the ALLL. When information confirms all or part of specific loans to be uncollectible, these amounts are promptly charged off against the ALLL. The following tables summarize the primary segments of the loan portfolio (in thousands): Commercial Real estate- Real Real estate- Consumer Total ALLL balance at December 31, 2014 $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Charge-offs (280 ) (385 ) (425 ) (92 ) (15 ) (1,197 ) Recoveries 207 — 186 5 23 421 Provision 298 (207 ) (325 ) 589 (40 ) 315 ALLL balance at December 31, 2015 $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Commercial Real estate- Real Real estate- Consumer Total ALLL balance at December 31, 2013 $ 614 $ 576 $ 3,664 $ 2,170 $ 22 $ 7,046 Charge-offs (237 ) — (671 ) (260 ) (44 ) (1,212 ) Recoveries 121 60 267 40 154 642 Provision 144 232 443 (374 ) (75 ) 370 ALLL balance at December 31, 2014 $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Commercial Real estate- Real Real estate- Consumer Total ALLL balance at December 31, 2012 $ 1,732 $ 1,123 $ 2,872 $ 1,991 $ 61 $ 7,779 Charge-offs (419 ) (191 ) (675 ) — (45 ) (1,330 ) Recoveries 191 33 107 46 24 401 Provision (890 ) (389 ) 1,360 133 (18 ) 196 ALLL balance at December 31, 2013 $ 614 $ 576 $ 3,664 $ 2,170 $ 22 $ 7,046 The decrease in the ALLL balance for real estate construction was largely due to a $0.4 million charge off. The decrease in the ALLL balance for residential real estate was largely due to aggregate charge offs of $0.3 million of loans secured by first liens. The increase in the ALLL balance for commercial real estate is mostly due to the 21.5% growth in the portfolio.

Other Real Estate Owned OREO _T

Other Real Estate Owned OREO [Text Block]	12 Months Ended
	Dec. 31, 2015
Other Real Estate Owned OREO [Text Block]	5. OTHER REAL ESTATE OWNED (“OREO”) OREO comprises foreclosed assets acquired in settlement of loans and is carried at fair value less estimated cost to sell and is included in other assets on the Consolidated Balance Sheet. As of December 31, 2015, and December 31, 2014, there were $1.4 million and $2.6 million, respectively, of OREO. As of December 31, 2015, the Company has initiated formal foreclosure proceedings on $1.1 million of real estate.

Property, Plant and Equipment D

Property, Plant and Equipment Disclosure [Text Block]	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment Disclosure [Text Block]	6. PREMISES AND EQUIPMENT Major classifications of premises and equipment at December 31: (Dollar amounts in thousands) 2015 2014 Land and land improvements $ 1,943 $ 1,943 Building and leasehold improvements 11,414 11,133 Furniture, fixtures, and equipment 4,853 4,637 18,210 17,713 Less accumulated depreciation and amortization 8,438 7,733 Total $ 9,772 $ 9,980 Depreciation and amortization charged to operations was $715,000 in 2015, $750,000 in 2014, and $676,000 in 2013.

Goodwill and Intangible Assets

Goodwill and Intangible Assets Disclosure [Text Block]	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Text Block]	7. GOODWILL AND INTANGIBLE ASSETS Goodwill totaled $4,559,000 at the years ended December 31, 2015, and 2014. Core deposit intangible carrying amount was $76,000 and $116,000 for the years ended December 31, 2015, and 2014. Core deposit accumulated amortization was $320,000 and $280,000 for the years ended December 31, 2015, and 2014. Core deposit intangible assets are amortized on a straight-line basis over their estimated lives of ten years. Amortization expense totaled $40,000 in 2015, 2014, and 2013, respectively. The estimated aggregate future amortization expense for core deposit intangible assets as of December 31, 2015, is $40,000 in 2017 and $36,000 in 2018.

Other Assets Disclosure _Text B

Other Assets Disclosure [Text Block]	12 Months Ended
	Dec. 31, 2015
Other Assets Disclosure [Text Block]	8. OTHER ASSETS The components of other assets at the years ended December 31: (Dollar amounts in thousands) 2015 2014 FHLB stock $ 1,887 $ 1,887 Accrued interest on investment securities 1,010 1,005 Accrued interest on loans 1,377 1,090 Deferred tax asset, net 959 1,484 Other 2,244 1,579 Total $ 7,477 $ 7,045

Deposit Liabilities Disclosures

Deposit Liabilities Disclosures [Text Block]	12 Months Ended
	Dec. 31, 2015
Deposit Liabilities Disclosures [Text Block]	9. DEPOSITS Time deposits at December 31, 2015, mature $92.9 million, $30.2 million, $11.0 million, $9.0 million, and $48.2 million during 2016, 2017, 2018, 2019, and 2020, respectively. The aggregate of all time deposit accounts of $250,000 or more amounted to $29.0 million and $54.6 million at December 31, 2015 and 2014, respectively.

Short-term Debt _Text Block_

Short-term Debt [Text Block]	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Text Block]	10. SHORT-TERM BORROWINGS The year ended December 31 outstanding balances and related information of short-term borrowings, which includes securities sold under agreements to repurchase and short-term borrowings from other banks, are summarized as follows: (Dollar amounts in thousands) 2015 2014 Balance at year-end $ 35,825 $ 14,808 Average balance outstanding 11,768 8,379 Maximum month-end balance 35,825 19,970 Weighted-average rate at year-end 1.37 % 0.98 % Weighted-average rate during the year 1.65 % 1.77 % Average balances outstanding during the year represent daily average balances, and average interest rates represent interest expense divided by the related average balance. The Company maintains a $4.0 million line of credit at an adjustable rate, currently 3.92%, a $3.0 million line of credit at an adjustable rate, currently at 4.00%, and a $2.5 million line of credit at an adjustable rate, currently 3.75%. At December 31, 2015, 2014, and 2013, outstanding borrowings under these lines were $9.5 million, $3.1 million, and $3.9 million, respectively. The following table provides additional detail regarding short-term borrowed funds. Repurchase Agreements (Sweep) December 31, 2015 December 31, 2014 Repurchase agreements: U.S. Government agency securities $ 1,052 $ 1,090 Mortgage-backed securities in government-sponsored entities 1,877 2,091 $ 2,929 $ 3,181

Other Borrowings _Text Block_

Other Borrowings [Text Block]	12 Months Ended
	Dec. 31, 2015
Other Borrowings [Text Block]	11. OTHER BORROWINGS Other borrowings consist of advances from the FHLB and subordinated debt as follows: (Dollar amounts in thousands) Description Maturity range Weighted- Stated interest from to from to 2015 2014 Fixed-rate amortizing 07/01/17 10/01/28 4.02 % 2.99 % 4.47 % $ 1,691 $ 2,376 Junior subordinated debt 12/21/37 12/21/37 1.95 % 1.90 1.99 8,248 8,248 Total $ 9,939 $ 10,624 The scheduled maturities of other borrowings are as follows: (Dollar amounts in thousands) Year Ending December 31, Amount Weighted- 2016 502 4.00 % 2017 373 4.00 % 2018 252 4.02 % 2019 155 4.04 % 2020 116 4.04 % Beyond 2020 8,542 1.51 % Total $ 9,939 1.84 % Fixed-rate amortizing advances from the FHLB require monthly principal and interest payments and an annual 20 percent paydown of outstanding principal. Monthly principal and interest payments are adjusted after each 20 percent paydown. Under the terms of a blanket agreement, FHLB borrowings are secured by certain qualifying assets of the Company which consist principally of first mortgage loans or mortgage-backed securities. Under this credit arrangement, the Company has a remaining borrowing capacity of approximately $80.0 million at December 31, 2015. The Company formed a special purpose entity (“Entity”) to issue $8,000,000 of floating rate, obligated mandatorily redeemable securities, and $248,000 in common securities as part of a pooled offering. The rate adjusts quarterly, equal to LIBOR plus 1.67%. The Entity may redeem them, in whole or in part, at face value. The Company borrowed the proceeds of the issuance from the Entity in December 2006 in the form of an $8,248,000 note payable, which is included in the other borrowings on the Company’s Consolidated Balance Sheet.

Other Liabilities

Other Liabilities	12 Months Ended
	Dec. 31, 2015
Other Liabilities	12. OTHER LIABILITIES The components of other liabilities are as follows: (Dollar amounts in thousands) 2015 2014 Accrued interest payable $ 395 $ 315 Supplemental Executive Retirement Plan 1,091 828 Accrued salary expense 689 609 Other 449 368 Total $ 2,624 $ 2,120

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2015
Income Taxes	13. INCOME TAXES The provision for federal income taxes consists of: (Dollar amounts in thousands) 2015 2014 2013 Current payable $ 1,004 $ 2,146 $ 1,556 Deferred 558 (154 ) 423 Total provision $ 1,562 $ 1,992 $ 1,979 The tax effects of deductible and taxable temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities are as follows: (Dollar amounts in thousands) 2015 2014 Deferred tax assets: Allowance for loan and lease losses $ 2,171 $ 2,328 Supplemental retirement plan 371 282 Investment security basis adjustment 66 66 Nonaccrual interest income 415 444 Deferred origination fees, net 12 295 OREO adjustments 92 94 Accrued compensation 234 207 Other 23 14 Gross deferred tax assets 3,384 3,730 Deferred tax liabilities: Premises and equipment 514 385 Net unrealized gain on securities 1,233 1,311 FHLB stock dividends 225 225 Intangibles 401 353 Mortgage servicing rights 68 — Other 44 77 Gross deferred tax liabilities 2,485 2,351 Net deferred tax assets $ 899 $ 1,379 No valuation allowance was established at December 31, 2015 and 2014, in view of the Company’s ability to carry back to taxes paid in previous years and certain tax strategies, coupled with the anticipated future taxable income as evidenced by the Company’s earnings potential. The reconciliation between the federal statutory rate and the Company’s effective consolidated income tax rate is as follows: (Dollar amounts in thousands) 2015 2014 2013 Amount % of Amount % of Amount % of Provision at statutory rate $ 2,866 34.0 % $ 3,119 34.0 % $ 3,062 34.0 % Tax-free income (1,347 ) (15.9 ) (1,187 ) (12.9 ) (1,138 ) (12.6 ) Nondeductible interest expense 34 0.4 37 0.4 45 0.5 Other 9 0.0 23 0.2 10 0.1 Actual tax expense and effective rate $ 1,562 18.5 % $ 1,992 21.7 % $ 1,979 22.0 % ASC 740-10 prescribes a recognition threshold and a measurement attribute for the financial statement recognition and measurement of a tax position taken or expected to be taken in a tax return. Benefits from tax positions should be recognized in the financial statements only when it is more likely than not that the tax position will be sustained upon examination by the appropriate taxing authority that would have full knowledge of all relevant information. A tax position that meets the more-likely-than-not recognition threshold is measured at the largest amount of benefit that is greater than 50 percent likely of being realized upon ultimate settlement. Tax positions that previously failed to meet the more-likely-than-not recognition threshold should be recognized in the first subsequent financial reporting period in which that threshold is met. Previously recognized tax positions that no longer meet the more-likely-than-not recognition threshold should be derecognized in the first subsequent financial reporting period in which that threshold is no longer met. At December 31, 2015 and December 31, 2014, the Company had no unrecognized tax benefits. The Company does not expect the total amount of unrecognized tax benefits to significantly increase within the next 12 months. The Company recognizes interest and penalties on unrecognized tax benefits as a component of income tax expense. The Company and the Bank are subject to U.S. federal income tax as well as an income tax in the state of Ohio, and the Bank is subject to a capital-based franchise tax in the state of Ohio. The Company and the Bank are no longer subject to examination by taxing authorities for years before December 31, 2012.

Compensation and Employee Benef

Compensation and Employee Benefit Plans [Text Block]	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Compensation and Employee Benefit Plans [Text Block]	NOTE 2 – STOCK-BASED COMPENSATION The Company had no unvested stock options outstanding or unrecognized stock-based compensation costs outstanding as of September 30, 2016 and 2015. Stock option activity during the nine months ended September 30 is as follows: 2016 Weighted- 2015 Weighted- Outstanding, January 1 31,949 $ 25.03 46,451 $ 27.90 Expired — — (3,639 ) 37.33 Exercised — — (1,025 ) 20.21 Outstanding, September 30 31,949 $ 25.03 41,787 $ 27.27 Exercisable, September 30 31,949 $ 25.03 41,787 $ 27.27	14. EMPLOYEE BENEFITS Retirement Plan The Bank maintains section 401(k) employee savings and investment plans for all full-time employees and officers of the Bank with more than one year of service. The Bank’s contributions to the plans are based on 50 percent matching of voluntary contributions up to 6 percent of compensation. An eligible employee can contribute up to 100 percent of salary. Employee contributions are vested at all times, and MBC contributions are fully vested after six years beginning at the second year in 20 percent increments. Contributions for 2015, 2014, and 2013 to these plans amounted to $156,000, $143,000, and $155,000, respectively. Supplemental Retirement Plan Until 2001, MBC maintained a Directors’ Retirement Plan to provide postretirement payments over a ten-year period to members of the Board of Directors who had completed five or more years of service. The plan required payment of 25 percent of the final average annual board fees paid to a director in the three years preceding the director’s retirement. The following table illustrates the components of the projected payments for the Directors’ Retirement Plan for the years ended: Projected 2016 $ 29,000 2017 23,000 2018 18,000 2019 12,000 2020 10,000 2021 2,000 Total $ 94,000 The retirement plan is available solely for nonemployee directors of The Middlefield Banking Company, but the Bank has not entered into any additional retirement arrangements for nonemployee directors since 2001. All director participants have retired. Executive Deferred Compensation Plan The Company maintains an Executive Deferred Compensation Plan (the “Plan”) to provide post-retirement payments to members of senior management. The Plan agreements are noncontributory, defined contribution arrangements that provide supplemental retirement income benefits to several officers, with contributions made solely by the Bank. During 2015, 2014, and 2013, the Company contributed $65,000, $115,000, and $120,000, respectively, to the Plan. Stock Option and Restricted Stock Plan The Company maintains a stock option and restricted stock plan (“the Plan”) for granting incentive stock options, nonqualified stock options, and restricted stock to key officers and employees and nonemployee directors of the Company. A total of 160,000 shares of authorized and unissued or issued common stock were reserved for issuance under the Plan, which expires ten years from the date of stockholder ratification. The per share exercise price of an option granted will not be less than the fair value of a share of common stock on the date the option is granted. The following table presents share data related to the outstanding options: 2015 Weighted- 2014 Weighted- Outstanding, January 1 $ 46,451 $ 27.90 $ 58,581 $ 28.38 Expired (10,802 ) 36.93 — — Exercised (2,175 ) 21.31 (11,223 ) 30.45 Forfeited (1,525 ) 33.53 (907 ) 27.35 Outstanding, December 31 $ 31,949 $ 25.03 $ 46,451 $ 27.90 Exercisable, December 31 $ 31,949 $ 25.03 $ 46,451 $ 27.90 The following table summarizes the characteristics of stock options at December 31, 2015: Outstanding Exercisable Grant Date Exercise Shares Contractual Average Shares Average December 10, 2006 40.24 2,625 0.94 40.24 2,625 40.24 May 16, 2007 37.48 1,337 1.37 37.48 1,337 37.48 December 10, 2007 37.00 1,950 1.94 37.00 1,950 37.00 January 2, 2008 36.25 1,337 2.00 36.25 1,337 36.25 November 10, 2008 23.00 16,500 2.86 23.00 16,500 23.00 May 9, 2011 17.55 8,200 5.35 17.55 8,200 17.55 31,949 31,949 No options were granted for the years ended December 31, 2015 and 2014. The Company recognizes compensation expense in the amount of fair value of the common stock at the grant date and as an addition to stockholders’ equity.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2015
Commitments	15. COMMITMENTS In the normal course of business, there are various outstanding commitments and certain contingent liabilities which are not reflected in the accompanying consolidated financial statements. These commitments and contingent liabilities represent financial instruments with off-balance sheet risk. The contract or notional amounts of those instruments reflect the extent of involvement in particular types of financial instruments which were composed of the following: (Dollar amounts in thousands) 2015 2014 Commitments to extend credit $ 112,134 $ 97,947 Standby letters of credit 4,404 4,514 Total $ 116,538 $ 102,461 These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the Consolidated Balance Sheet. The Company’s exposure to credit loss, in the event of nonperformance by the other parties to the financial instruments, is represented by the contractual amounts as disclosed. The Company minimizes its exposure to credit loss under these commitments by subjecting them to credit approval and review procedures and collateral requirements as deemed necessary. Commitments generally have fixed expiration dates within one year of their origination. Standby letters of credit are conditional commitments issued by the Company to guarantee the performance of a customer to a third party. Performance letters of credit represent conditional commitments issued by the Company to guarantee the performance of a customer to a third party. These instruments are issued primarily to support bid or performance-related contracts. The coverage period for these instruments is typically a one-year period with an annual renewal option subject to prior approval by management. Fees earned from the issuance of these letters are recognized over the coverage period. For secured letters of credit, the collateral is typically bank deposit instruments or customer business assets. Commitments to fund certain mortgage loans (interest rate locks) to be sold into the secondary market and forward contracts for the future delivery of these mortgage loans are considered derivatives. It is the Company’s practice to enter into the forward contracts for the future purchase of mortgage-backed securities when interest rate lock commitments are entered into in order to economically hedge the effect of changes in interest rates resulting from its commitments to fund the loans. These mortgage banking derivatives are not formally designated as hedge relationships. The derivative assets and liabilities are considered immaterial as of December 31, 2015. Associated income and expense is reported in gains on sale of loans. Leasing Arrangements The Company leases certain of its banking facilities under operating leases which contain certain renewal options. As of December 31, 2015, approximate future minimum rental payments, including the renewal options under these leases, are as follows (in thousands): 2016 $ 285 2017 293 2018 294 2019 289 2020 301 Thereafter 2,055 $ 3,517 The above amounts represent minimum rentals not adjusted for possible future increases due to escalation provisions and assume that all renewal option periods will be exercised by the Company. Rent expense approximated $288,000, $269,000, and $301,000 for the years ended December 31, 2015, 2014, and 2013, respectively.

Regulatory Restrictions

Regulatory Restrictions	12 Months Ended
	Dec. 31, 2015
Regulatory Restrictions	16. REGULATORY RESTRICTIONS The Company is subject to the regulatory requirements of the Federal Reserve System as a bank holding company. The bank is subject to regulations of the Federal Deposit Insurance Corporation (“FDIC”) and the State of Ohio, Division of Financial Institutions. Since the establishment in the fourth quarter of 2009 of Middlefield Banc Corp.’s nonbank-asset resolution subsidiary, EMORECO, Inc., the Bank has sold $5.8 million of nonperforming assets to this subsidiary. Cash Requirements The Cleveland district Federal Reserve Bank requires the Company to maintain certain average reserve balances. As of December 31, 2015 and 2014, the Bank had required reserves of $6.9 million and $6.8 million comprising vault cash and a depository amount held with the Federal Reserve Bank. Loans Federal law prevents the Company from borrowing from the Bank unless the loans are secured by specific obligations. Further, such secured loans are limited in amount of 10 percent of the Bank’s common stock and capital surplus. Dividends MBC is subject to dividend restrictions that generally limit the amount of dividends that can be paid by an Ohio state-chartered bank. Under the Ohio Banking Code, cash dividends may not exceed net profits as defined for that year combined with retained net profits for the two preceding years less any required transfers to surplus. Under this formula the amount available for payment of dividends for 2015 approximates $8.5 million plus 2016 profits retained up to the date of the dividend declaration. As a condition to the ODFI’s approval of the merger of Emerald Bank into MBC, until the third anniversary of the merger, that is until January 20, 2017, MBC will have to obtain the ODFI’s advance approval for dividend payments to the Company.

Regulatory Capital

Regulatory Capital	12 Months Ended
	Dec. 31, 2015
Regulatory Capital	17. REGULATORY CAPITAL The Bank and Company are subject to regulatory capital requirements administered by banking agencies. Capital adequacy guidelines and prompt corrective-action regulations involve quantitative measures of assets, liabilities, and certain off-balance-sheet items calculated under regulatory accounting practices. Capital amounts and classifications are also subject to qualitative judgments by regulators about components, risk weightings, and other factors and the regulators can lower classifications in certain cases. Failure to meet various capital requirements can initiate regulatory action that could have a direct material effect on the financial statements. Management believes as of December 31, 2015, the Bank and Company have met all capital adequacy requirements to which it is subject. The prompt corrective action regulations provide five classifications, including well capitalized, adequately capitalized, under-capitalized, significantly undercapitalized, and critically undercapitalized, although these terms are not used to represent overall financial condition. If adequately capitalized, regulatory approval is required to accept brokered deposits. If undercapitalized, capital distributions are limited, as is asset growth and expansion, and plans for capital restoration are required. The Basel III Capital Rules became effective for the Bank on January 1, 2015 and certain provisions are subject to a phase-in period. The implementation of the capital conservation buffer will begin on January 1, 2016 at the 0.625% level and be phased in over a four -year period (increasing by that amount on each subsequent January 1, until it reaches 2.5% on January 1, 2019). The Basel III Capital Rules also provide for a “countercyclical capital buffer” that is applicable to only certain covered institutions and does not have any current applicability to the Bank. The capital conservation buffer is designed to absorb losses during periods of economic stress. Banking institutions with a ratio of Common Equity Tier 1 capital to risk-weighted assets above the minimum but below the conservation buffer (or below the combined capital conservation buffer and countercyclical capital buffer, when the latter is applied) will face constraints on dividends, equity repurchases and compensation based on the amount of the shortfall. The following tables present actual and required capital ratios as of December 31, 2015 under the Basel III Capital Rules. Capital levels required to be considered well capitalized are based upon prompt corrective action regulations, as amended to reflect the changes under the Basel III Capital Rules. As of December 31, 2015 Leverage Tier 1 Risk Common Total Risk The Middlefield Banking Company 9.23 % 12.52 % 12.52 % 13.73 % Middlefield Banc Corp. 8.69 % 12.00 % 12.00 % 13.20 % Adequately capitalized ratio 4.00 % 6.00 % 4.50 % 8.00 % Adequately capitalized ratio plus capital conservation buffer 4.00 % 8.50 % 7.00 % 10.50 % Well-capitalized ratio (Bank only) 5.00 % 8.00 % 6.50 % 10.00 % See Note 15 for additional information concerning regulatory capital requirements The Company’s and its subsidiary’s actual capital ratios are presented in the following table that shows that all regulatory capital requirements were met as of December 31, 2014. As of December 31, 2014 Leverage Tier 1 Risk Total Risk The Middlefield Banking Company 9.25 % 12.95 % 14.19 % Middlefield Banc Corp. 9.60 % 13.38 % 14.64 % Adequately capitalized ratio 4.00 % 4.00 % 8.00 % Well-capitalized ratio (Bank only) 5.00 % 6.00 % 10.00 %

Fair Value Disclosure Measureme

Fair Value Disclosure Measurements	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value Disclosure Measurements	NOTE 4 – FAIR VALUE MEASUREMENTS Fair value is defined as the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market for an asset or liability in an orderly transaction between market participants at the measurement date. GAAP established a fair value hierarchy that prioritizes the use of inputs used in valuation methodologies into the following levels: Level I: Quoted prices are available in active markets for identical assets or liabilities as of the reported date. Level II: Pricing inputs are other than the quoted prices in active markets, which are either directly or indirectly observable as of the reported date. The nature of these assets and liabilities includes items for which quoted prices are available but traded less frequently and items that are fair valued using other financial instruments, the parameters of which can be directly observed. Level III: Assets and liabilities that have little to no pricing observability as of the reported date. These items do not have two-way markets and are measured using management’s best estimate of fair value, where the inputs into the determination of fair value require significant management judgment or estimation. The following tables present the assets measured on a recurring basis on the Consolidated Balance Sheet at their fair value by level within the fair value hierarchy. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. September 30, 2016 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 10,863 $ — $ 10,863 Obligations of states and political subdivisions — 87,525 — 87,525 Mortgage-backed securities in government-sponsored entities — 21,380 — 21,380 Private-label mortgage-backed securities — 2,068 — 2,068 Total debt securities — 121,836 — 121,836 Equity securities in financial institutions 5 1,213 — 1,218 Total $ 5 $ 123,049 $ — $ 123,054 December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 21,629 $ — $ 21,629 Obligations of states and political subdivisions — 97,290 — 97,290 Mortgage-backed securities in government-sponsored entities — 24,524 — 24,524 Private-label mortgage-backed securities — 2,263 — 2,263 Total debt securities — 145,706 — 145,706 Equity securities in financial institutions 5 809 — 814 Total $ 5 $ 146,515 $ — $ 146,520 The Company obtains fair values from an independent pricing service which represent either quoted market prices for the identical securities (Level I inputs) or fair values determined by pricing models using a market approach that considers observable market data, such as interest rate volatilities, LIBOR yield curve, credit spreads and prices from market makers and live trading systems (Level II). Financial instruments are considered Level III when their values are determined using pricing models, discounted cash flow methodologies or similar techniques and at least one significant model assumption or input is unobservable. In addition to these unobservable inputs, the valuation models for Level III financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Level III financial instruments also include those for which the determination of fair value requires significant management judgment or estimation. The Company has no securities considered to be Level III as of September 30, 2016 or December 31, 2015. The Company uses prices compiled by third party vendors. The following tables present the assets measured on a nonrecurring basis on the Consolidated Balance Sheet at their fair value by level within the fair value hierarchy. Impaired loans that are collateral dependent are written down to fair value through the establishment of specific reserves. Techniques used to value the collateral that secure the impaired loan include quoted market prices for identical assets classified as Level I inputs and observable inputs, employed by certified appraisers, for similar assets classified as Level II inputs. In cases where valuation techniques included inputs that are unobservable and are based on estimates and assumptions developed by management based on the best information available under each circumstance, the asset valuation is classified as Level III inputs. The Company values other real estate owned at the estimated fair value of the underlying collateral less expected selling costs. Such values are estimated primarily using appraisals and reflect a market value approach. Due to the significance of the Level III inputs, other real estate owned has been classified as Level III. September 30, 2016 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a nonrecurring basis: Impaired loans $ — $ — $ 11,102 $ 11,102 Other real estate owned — — 1,205 1,205 December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a nonrecurring basis: Impaired loans $ — $ — $ 12,848 $ 12,848 Other real estate owned — — 1,412 1,412 The following tables present additional quantitative information about assets measured at fair value on a nonrecurring basis and for which the Company uses Level III inputs to determine fair value: Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Estimate Valuation Techniques Unobservable Input Range (Weighted Average) September 30, 2016 Impaired loans $ 7,743 Discounted cash flow Discount rate 3.1% to 7.0% (5.0%) 3,359 Appraisal of collateral (1) Appraisal adjustments (2) 0.0% to 55.7% (34.6%) Other real estate owned $ 1,205 Appraisal of collateral (1) Appraisal adjustments (2) 0.0% to 10.0% (7.3%) Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Estimate Valuation Techniques Unobservable Input Range (Weighted Average) December 31, 2015 Impaired loans $ 6,867 Discounted cash flow Discount rate 3.1% to 7.9% (5.0%) 5,981 Appraisal of collateral (1) Appraisal adjustments (2) 0.0% to 87.1% (23.3%) Other real estate owned $ 1,412 Appraisal of collateral (1) Appraisal adjustments (2) 0% to 10.0% (7.3%) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of liquidation expenses and other appraisal adjustments are presented as a percent of the appraisal. The estimated fair value of the Company’s financial instruments is as follows: September 30, 2016 Carrying Level I Level II Level III Total Fair (Dollar amounts in thousands) Financial assets: Cash and cash equivalents $ 23,276 $ 23,276 $ — $ — $ 23,276 Investment securities Available for sale 123,054 5 123,049 — 123,054 Loans held for sale 880 — 880 — 880 Net loans 579,995 — — 586,739 586,739 Bank-owned life insurance 13,438 13,438 — — 13,438 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,526 2,526 — — 2,526 Financial liabilities: Deposits $ 639,342 $ 454,427 $ — $ 188,668 $ 643,095 Short-term borrowings 32,803 32,803 — — 32,803 Other borrowings 9,713 — — 10,003 10,003 Accrued interest payable 391 391 — — 391 December 31, 2015 Carrying Level I Level II Level III Total Fair (Dollar amounts in thousands) Financial assets: Cash and cash equivalents $ 23,750 $ 23,750 $ — $ — $ 23,750 Investment securities Available for sale 146,520 5 146,515 — 146,520 Loans held for sale 1,107 — 1,107 — 1,107 Net loans 527,325 — — 534,021 534,021 Bank-owned life insurance 13,141 13,141 — — 13,141 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,387 2,387 — — 2,387 Financial liabilities: Deposits $ 624,447 $ 433,226 $ — $ 191,747 $ 624,973 Short-term borrowings 35,825 35,825 — — 35,825 Other borrowings 9,939 — 10,063 10,063 Accrued interest payable 395 395 — — 395 Financial instruments are defined as cash, evidence of ownership interest in an entity, or a contract which creates an obligation or right to receive or deliver cash or another financial instrument from/to a second entity on potentially favorable or unfavorable terms. Fair value is defined as the amount at which a financial instrument could be exchanged in a current transaction between willing parties other than in a forced liquidation sale. If a quoted market price is available for a financial instrument, the estimated fair value would be calculated based upon the market price per trading unit of the instrument. If no readily available market exists, the fair value estimates for financial instruments should be based upon management’s judgment regarding current economic conditions, interest rate risk, expected cash flows, future estimated losses, and other factors as determined through various option pricing formulas or simulation modeling. Since many of these assumptions result from judgments made by management based upon estimates which are inherently uncertain, the resulting estimated fair values may not be indicative of the amount realizable in the sale of a particular financial instrument. In addition, changes in assumptions on which the estimated fair values are based may have a significant impact on the resulting estimated fair values. As certain assets such as deferred tax assets and premises and equipment are not considered financial instruments, the estimated fair value of financial instruments would not represent the full value of the Company. The Company employed simulation modeling in determining the estimated fair value of financial instruments for which quoted market prices were not available based upon the following assumptions: Cash and Cash Equivalents, Federal Home Loan Bank Stock, Accrued Interest Receivable, Accrued Interest Payable, and Short-Term Borrowings The fair value is equal to the current carrying value. Bank-Owned Life Insurance The fair value is equal to the cash surrender value of the life insurance policies. Investment Securities Available for Sale The fair value of investment securities is equal to the available quoted market price. If no quoted market price is available, fair value is estimated using the quoted market price for similar securities. Loans Held for Sale Loans held for sale are carried at lower of cost or fair value. The fair value of loans held for sale is based on secondary market pricing on portfolios with similar characteristics. The changes in fair value of the assets are largely driven by changes in interest rates subsequent to loan funding and changes in the fair value of servicing associated with the mortgage loan held for sale. Net Loans The fair value is estimated by discounting future cash flows using current market inputs at which loans with similar terms and qualities would be made to borrowers of similar credit quality. Where quoted market prices were available, primarily for certain residential mortgage loans, such market rates were used as estimates for fair value. Deposits and Other Borrowings The fair values of certificates of deposit and other borrowings are based on the discounted value of contractual cash flows. The discount rates are estimated using rates currently offered for similar instruments with similar remaining maturities. Demand, savings, and money market deposits are valued at the amount payable on demand as of period end. Commitments to Extend Credit These financial instruments are generally not subject to sale, and estimated fair values are not readily available. The carrying value, represented by the net deferred fee arising from the unrecognized commitment or letter of credit, and the fair value, determined by discounting the remaining contractual fee over the term of the commitment using fees currently charged to enter into similar agreements with similar credit risk, are not considered material for disclosure.	18. FAIR VALUE DISCLOSURE MEASUREMENTS The following disclosures show the hierarchal disclosure framework associated with the level of pricing observations utilized in measuring assets and liabilities at fair value. The three broad levels defined by U.S. generally accepted accounting principles are as follows: Level I: Quoted prices are available in active markets for identical assets or liabilities as of the reported date. Level II: Pricing inputs are other than the quoted prices in active markets, which are either directly or indirectly observable as of the reported date. The nature of these assets and liabilities includes items for which quoted prices are available but traded less frequently and items that are fair-valued using other financial instruments, the parameters of which can be directly observed. Level III: Valuations derived from valuation techniques in which one or more significant inputs or significant value drivers are unobservable. This hierarchy requires the use of observable market data when available. The following tables present the assets measured on a recurring basis on the Consolidated Balance Sheet at their fair value as of December 31, 2015 and 2014, by level within the fair value hierarchy. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 21,629 $ — $ 21,629 Obligations of states and political subdivisions — 97,290 — 97,290 Mortgage-backed securities in government- sponsored entities — 24,524 — 24,524 Private-label mortgage-backed securities — 2,263 — 2,263 Total debt securities — 145,706 — 145,706 Equity securities in financial institutions — 814 — 814 Total $ — $ 146,520 $ — $ 146,520 December 31, 2014 Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 22,896 $ — $ 22,896 Obligations of states and political subdivisions — 98,345 — 98,345 Mortgage-backed securities in government- sponsored entities — 29,391 — 29,391 Private-label mortgage-backed securities — 2,919 — 2,919 Total debt securities — 153,551 — 153,551 Equity securities in financial institutions — 783 — 783 Total $ — $ 154,334 $ — $ 154,334 Financial instruments are considered Level III when their values are determined using pricing models, discounted cash flow methodologies or similar techniques and at least one significant model assumption or input is unobservable. In addition to these unobservable inputs, the valuation models for Level III financial instruments typically also rely on a number of inputs that are readily observable either directly or indirectly. Level III financial instruments also include those for which the determination of fair value requires significant management judgment or estimation. The following tables present the assets measured on a non-recurring basis on the Consolidated Balance Sheet at their fair value by level within the fair value hierarchy. Impaired loans that are collateral dependent are written down to fair value through the establishment of specific reserves. Techniques used to value the collateral that secure the impaired loan include quoted market prices for identical assets classified as Level I inputs and observable inputs, employed by certified appraisers, for similar assets classified as Level II inputs. In cases where valuation techniques included inputs that are unobservable and are based on estimates and assumptions developed by management based on the best information available under each circumstance, the asset valuation is classified as Level III inputs. December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a non-recurring basis: Impaired loans $ — $ — $ 12,848 $ 12,848 Other real estate owned — — 1,412 1,412 December 31, 2014 Level I Level II Level III Total Assets measured on a non-recurring basis: Impaired loans $ — $ — $ 12,772 $ 12,772 Other real estate owned — — 2,590 2,590 The following tables present additional quantitative information about assets measured at fair value on a non-recurring basis and for which the Company uses Level III inputs to determine fair value: Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Valuation Unobservable Range (Weighted Average) December 31, 2015 Impaired loans $ 6,867 Discounted cash flow Discount rate 3.1% to 7.9% (5.0%) 5,981 Appraisal of collateral (1) Appraisal 0.0% to 87.1% (23.3%) Other real estate owned $ 1,412 Appraisal of collateral (1) Appraisal 0.0% to 10.0% (7.3%) Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Valuation Unobservable Range (Weighted Average) December 31, 2014 Impaired loans $ 12,772 Appraisal of collateral (1) Appraisal adjustments (2) 0% to 84.6% (25.5%) Other real estate owned $ 2,590 Appraisal of collateral (1) Appraisal adjustments (2) 0% to 10.0% (7.5%) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of liquidation expenses and other appraisal adjustments are presented as a percent of the appraisal. The estimated fair value of the Company’s financial instruments is as follows: December 31, 2015 Carrying Level I Level II Level III Total Fair (in thousands) Financial assets: Cash and cash equivalents $ 23,750 $ 23,750 $ — $ — $ 23,750 Investment securities available for sale 146,520 — 146,520 — 146,520 Loans held for sale 1,107 — 1,107 — 1,107 Net loans 527,325 — — 534,021 534,021 Bank-owned life insurance 13,141 13,141 — — 13,141 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,387 2,387 — — 2,387 Financial liabilities: Deposits $ 624,447 $ 433,226 $ — $ 191,747 $ 624,973 Short-term borrowings 35,825 35,825 — — 35,825 Other borrowings 9,939 — 10,063 10,063 Accrued interest payable 395 395 — — 395 December 31, 2014 Carrying Level I Level II Level III Total Fair (in thousands) Financial assets: Cash and cash equivalents $ 25,639 $ 25,639 $ — $ — $ 25,639 Investment securities available for sale 154,334 — 154,334 — 154,334 Loans held for sale 438 — 438 — 438 Net loans 463,738 — — 475,019 475,019 Bank-owned life insurance 9,092 9,092 — — 9,092 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,095 2,095 — — 2,095 Financial liabilities: Deposits $ 586,112 $ 416,254 $ — $ 170,542 $ 586,796 Short-term borrowings 14,808 14,808 — — 14,808 Other borrowings 10,624 — 10,822 10,822 Accrued interest payable 315 315 — — 315 Financial instruments are defined as cash, evidence of ownership interest in an entity, or a contract which creates an obligation or right to receive or deliver cash or another financial instrument from/to a second entity on potentially favorable or unfavorable terms. Fair value is defined as the amount at which a financial instrument could be exchanged in a current transaction between willing parties other than in a forced liquidation sale. If a quoted market price is available for a financial instrument, the estimated fair value would be calculated based upon the market price per trading unit of the instrument. If no readily available market exists, the fair value estimates for financial instruments should be based upon management’s judgment regarding current economic conditions, interest rate risk, expected cash flows, future estimated losses, and other factors as determined through various option pricing formulas or simulation modeling. Since many of these assumptions result from judgments made by management based upon estimates which are inherently uncertain, the resulting estimated fair values may not be indicative of the amount realizable in the sale of a particular financial instrument. In addition, changes in assumptions on which the estimated fair values are based may have a significant impact on the resulting estimated fair values. As certain assets such as deferred tax assets and premises and equipment are not considered financial instruments, the estimated fair value of financial instruments would not represent the full value of the Company. The Company employed simulation modeling in determining the estimated fair value of financial instruments for which quoted market prices were not available based upon the following assumptions. Cash and Cash Equivalents, Federal Home Loan Bank Stock, Accrued Interest Receivable, Accrued Interest Payable, and Short-Term Borrowings The fair value is equal to the current carrying value. Bank-Owned Life Insurance The fair value is equal to the cash surrender value of the life insurance policies. Investment Securities Available for Sale The fair value of investment securities is equal to the available quoted market price. If no quoted market price is available, fair value is estimated using the quoted market price for similar securities. Loans The fair value is estimated by discounting future cash flows using current market inputs at which loans with similar terms and qualities would be made to borrowers of similar credit quality. Where quoted market prices were available, primarily for certain residential mortgage loans, such market rates were utilized as estimates for fair value. Mortgage loans held for sale Mortgage loans held for sale are carried at their fair value. Mortgage loans held for sale are estimated using security prices for similar product types and, therefore, are classified in Level II. Deposits and Other Borrowed Funds The fair values of certificates of deposit and other borrowed funds are based on the discounted value of contractual cash flows. The discount rates are estimated using rates currently offered for similar instruments with similar remaining maturities. Demand, savings, and money market deposits are valued at the amount payable on demand as of year-end. Commitments to Extend Credit These financial instruments are generally not subject to sale, and estimated fair values are not readily available. The carrying value, represented by the net deferred fee arising from the unrecognized commitment or letter of credit, and the fair value, determined by discounting the remaining contractual fee over the term of the commitment using fees currently charged to enter into similar agreements with similar credit risk, are not considered material for disclosure. The contractual amounts of unfunded commitments and letters of credit are presented in Note 14.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Accumulated Other Comprehensive Income	NOTE 5 – ACCUMULATED OTHER COMPREHENSIVE INCOME The following tables present the changes in accumulated other comprehensive income by component net of tax for the three and nine months ended September 30, 2016 and 2015, respectively: (Dollars in thousands) Unrealized gains on Balance as of December 31, 2015 $ 2,395 Other comprehensive income before reclassification 1,421 Amount reclassified from accumulated other comprehensive income (200 ) Period change 1,221 Balance at September 30, 2016 $ 3,616 Balance at June 30, 2016 $ 3,879 Other comprehensive income before reclassification (263 ) Amount reclassified from accumulated other comprehensive income — Period change (263 ) Balance at September 30, 2016 $ 3,616 (Dollars in thousands) Unrealized gains on Balance as of December 31, 2014 $ 2,548 Other comprehensive income before reclassification (461 ) Amount reclassified from accumulated other comprehensive income (170 ) Period change (631 ) Balance at September 30, 2015 1,917 Balance as of June 30, 2015 $ 1,122 Other comprehensive loss before reclassification 935 Amount reclassified from accumulated other comprehensive income (140 ) Period change 795 Balance at September 30, 2015 $ 1,917 The following tables present significant amounts reclassified out of each component of accumulated other comprehensive income for the three and nine months ended September 30, 2016 and 2015, respectively: (Dollars in thousands) Details about other Amount Reclassified from Accumulated Other Comprehensive Income (a) For the Three Months Ended Affected Line Item Presented September 30, 2016 September 30, 2015 Unrealized gains on available-for-sale securities $ — $ 211 Investment securities gains, net — (71 ) Income taxes $ — $ 140 Net of tax (Dollars in thousands) Details about other Amount Reclassified from Accumulated Other Comprehensive Income (a) Affected Line Item Net Income is Presented September 30, 2016 September 30, 2015 Unrealized gains on available-for-sale securities $ 303 $ 257 Investment securities gains, net (103 ) (87 ) Income taxes $ 200 $ 170 Net of tax (a) Amounts in parentheses indicate debits to net income	19. ACCUMULATED OTHER COMPREHENSIVE INCOME The following table presents the changes in accumulated other comprehensive income (loss) by component net of tax: (Dollars in thousands) Unrealized gains on Balance as of December 31, 2014 $ 2,548 Other comprehensive income before reclassification 60 Amount reclassified from accumulated other comprehensive income (213 ) Period change (153 ) Balance at December 31, 2015 $ 2,395 (Dollars in thousands) Unrealized gains on Balance as of December 31, 2013 ($ 2,237 ) Other comprehensive income before reclassification 4,949 Amount reclassified from accumulated other comprehensive income (164 ) Period change 4,785 Balance at December 31, 2014 $ 2,548 (a) All amounts are net of tax. Amounts in parentheses indicate debits. The following tables present significant amounts reclassified out of each component of accumulated other comprehensive income (loss): (Dollars in thousands) Details about other comprehensive income Amount Reclassified from Affected Line Item in the Statement Unrealized gains on available-for-sale securities $ 323 Investment securities gains, net (110 ) Income taxes $ 213 Net of tax (Dollars in thousands) Details about other comprehensive income Amount Reclassified from Affected Line Item in the Statement Unrealized gains on available-for-sale securities $ 248 Investment securities gains, net (84 ) Income taxes $ 164 Net of tax (a) Amounts in parentheses indicate debits to net income.

Parent Company

Parent Company	12 Months Ended
	Dec. 31, 2015
Parent Company	20. PARENT COMPANY Following are condensed financial statements for the Company. CONDENSED BALANCE SHEET (Dollar amounts in thousands) December 31, 2015 2014 ASSETS Cash and due from banks $ 1,329 $ 466 Investment securities available for sale 814 783 Investment in nonbank subsidiary 2,418 2,534 Investment in subsidiary bank 73,061 69,514 Other assets 2,475 1,981 TOTAL ASSETS $ 80,097 $ 75,278 LIABILITIES Trust preferred securities $ 8,248 $ 8,248 Short-term borrowings 9,499 3,136 Other liabilities 43 27 TOTAL LIABILITIES 17,790 11,411 STOCKHOLDERS’ EQUITY 62,307 63,867 TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY $ 80,097 $ 75,278 CONDENSED STATEMENT OF INCOME AND COMPREHENSIVE INCOME Year Ended December 31, (Dollar amounts in thousands) 2015 2014 2013 INCOME Dividends from subsidiary bank $ 4,023 $ 3,142 $ 2,198 Other 19 8 5 Total income 4,042 3,150 2,203 EXPENSES Interest expense 290 304 361 Other 860 816 475 Total expenses 1,150 1,120 836 Income before income tax benefit 2,892 2,030 1,367 Income tax benefit (386 ) (378 ) (283 ) Income before equity in undistributed net income of subsidiaries 3,278 2,408 1,650 Equity in undistributed net income of subsidiaries 3,587 4,772 5,378 NET INCOME $ 6,865 $ 7,180 $ 7,028 Comprehensive Income (Loss) $ 6,712 $ 11,965 $ (600 ) CONDENSED STATEMENT OF CASH FLOWS Year Ended December 31, (Dollar amounts in thousands) 2015 2014 2013 OPERATING ACTIVITIES Net income $ 6,865 $ 7,180 $ 7,028 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed net income of Middlefield Banking Company (3,703 ) (4,798 ) (4,884 ) Equity in undistributed net income of Emerald Bank — — (598 ) Equity in undistributed net loss of EMORECO 116 26 104 Stock-based compensation expense 18 10 — Other (503 ) (409 ) (253 ) Net cash provided by operating activities 2,793 2,009 1,397 FINANCING ACTIVITIES Net increase (decrease) in short-term borrowings 6,363 (759 ) (976 ) Purchase of treasury stock (6,784 ) — — Common stock issued — — 74 Stock options exercised (7 ) (50 ) (77 ) Proceeds from dividend reinvestment plan 651 590 736 Cash dividends (2,153 ) (2,121 ) (2,097 ) Net cash used for financing activities (1,930 ) (2,340 ) (2,340 ) Increase (decrease) in cash 863 (331 ) (943 ) CASH AT BEGINNING OF YEAR 466 797 1,740 CASH AT END OF YEAR $ 1,329 $ 466 $ 797

Selected Quarterly Financial Da

Selected Quarterly Financial Data (Unaudited)	12 Months Ended
	Dec. 31, 2015
Selected Quarterly Financial Data (Unaudited)	21. SELECTED QUARTERLY FINANCIAL DATA (Unaudited) (Dollar amounts in thousands) Three Months Ended March 31, June 30, September 30, December 31, Total interest income $ 7,035 $ 7,066 $ 7,151 $ 7,343 Total interest expense 883 990 959 988 Net interest income 6,152 6,076 6,192 6,355 Provision for loan losses 105 — 105 105 Net interest income after provision for loan losses 6,047 6,076 6,087 6,250 Total noninterest income 796 962 1,108 1,178 Total noninterest expense 4,811 5,217 4,669 5,380 Income before income taxes 2,032 1,821 2,526 2,048 Income taxes 404 316 544 298 Net income $ 1,628 $ 1,505 $ 1,982 $ 1,750 Per share data: Net income Basic $ 0.79 $ 0.73 $ 0.96 $ 0.93 Diluted 0.78 0.73 0.96 0.92 Average shares outstanding: Basic 2,053,660 2,058,986 2,064,054 1,884,484 Diluted 2,062,867 2,068,313 2,072,639 1,893,345 (Dollar amounts in thousands) Three Months Ended March 31, June 30, September 30, December 31, Total interest income $ 6,989 $ 6,919 $ 6,911 $ 7,055 Total interest expense 1,033 1,033 999 1,005 Net interest income 5,956 5,886 5,912 6,050 Provision for loan losses 180 120 70 — Net interest income after provision for loan losses 5,776 5,766 5,842 6,050 Total noninterest income 715 857 990 1,026 Total noninterest expense 4,229 4,598 4,385 4,638 Income before income taxes 2,262 2,025 2,447 2,438 Income taxes 499 414 529 550 Net income $ 1,763 $ 1,611 $ 1,918 $ 1,888 Per share data: Net income Basic $ 0.87 $ 0.79 $ 0.94 $ 0.92 Diluted 0.86 0.79 0.93 0.92 Average shares outstanding: Basic 2,033,480 2,038,026 2,044,124 2,049,536 Diluted 2,039,515 2,044,564 2,052,012 2,059,561

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies [Text Block]	9 Months Ended
	Sep. 30, 2016
Basis of Presentation and Significant Accounting Policies [Text Block]	NOTE 1 – BASIS OF PRESENTATION The consolidated financial statements of Middlefield Banc Corp. (“Company”) include its bank subsidiary, The Middlefield Banking Company (“MB”), and a nonbank asset resolution subsidiary EMORECO, Inc. All significant inter-company items have been eliminated. The accompanying unaudited financial statements have been prepared in accordance with U.S. generally accepted accounting principles and the instructions for Form 10-Q and Article 10 of Regulation S-X. In management’s opinion, the financial statements include all adjustments, consisting of normal recurring adjustments, that the Company considers necessary to fairly state the Company’s financial position and the results of operations and cash flows. The consolidated balance sheet at December 31, 2015, has been derived from the audited financial statements at that date but does not include all of the necessary informational disclosures and footnotes as required by U.S. generally accepted accounting principles. The accompanying financial statements should be read in conjunction with the financial statements and notes thereto included with the Company’s Form 10-K for the year ended December 31, 2015. The results of the Company’s operations for any interim period are not necessarily indicative of the results of the Company’s operations for any other interim period or for a full fiscal year. Recent Accounting Pronouncements – In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In June 2014, the FASB issued ASU 2014-12, Compensation – Stock Compensation (Topic 718): Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers Topic 606 In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In March 2016, the FASB issued ASU 2016-04, Liabilities Extinguishments of Liabilities (Subtopic 405-20). In March 2016, the FASB issued ASU 2016-05, Derivatives and Hedging (Topic 815) . In March 2016, the FASB issued ASU 2016-06, Derivatives and Hedging (Topic 815) In March 2016, the FASB issued ASU 2016-07, Investments Equity Method and Joint Ventures (Topic 323) In March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606). Revenue from Contracts with Customers (Topic 606), Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, In March 2016, the FASB issued ASU 2016-09, Compensation – Stock Compensation (Topic 718) Share-Based Payment In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606). Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606) Deferral of the Effective Date In May 2016, the FASB issued ASU 2016-11, Revenue Recognition (Topic 605) and Derivative and Hedging (Topic 815), which rescinds SEC paragraphs pursuant to two SEC Staff Announcements at the March 3, 2016, Emerging Issues Task Force meeting. This Update did not have a significant impact on the Company’s financial statements. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers (Topic 606), which among other things clarifies the objective of the collectability criterion in Topic 606, as well as certain narrow aspects of Topic 606. The amendments in this Update affect the guidance in ASU 2014-09, Revenue from Contracts with Customers (Topic 606), which is not yet effective. The effective date and transition requirements for the amendments in this Update are the same as the effective date and transition requirements for Topic 606 (and any other Topic amended by Update 2014-09). ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, defers the effective date of Update 2014-09 by one year. This Update is not expected to have a significant impact on the Company’s financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which changes the impairment model for most financial assets. This Update is intended to improve financial reporting by requiring timelier recording of credit losses on loans and other financial instruments held by financial institutions and other organizations. The underlying premise of the Update is that financial assets measured at amortized cost should be presented at the net amount expected to be collected, through an allowance for credit losses that is deducted from the amortized cost basis. The allowance for credit losses should reflect management’s current estimate of credit losses that are expected to occur over the remaining life of a financial asset. The income statement will be effected for the measurement of credit losses for newly recognized financial assets, as well as the expected increases or decreases of expected credit losses that have taken place during the period. ASU 2016-13 is effective for annual and interim periods beginning after December 15, 2019, and early adoption is permitted for annual and interim periods beginning after December 15, 2018. With certain exceptions, transition to the new requirements will be through a cumulative effect adjustment to opening retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The Company is currently evaluating the impact the adoption of the standard will have on the Company’s financial position or results of operations. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), which addresses eight specific cash flow issues with the objective of reducing diversity in practice. Among these include recognizing cash payments for debt prepayment or debt extinguishment as cash outflows for financing activities; cash proceeds received from the settlement of insurance claims should be classified on the basis of the related insurance coverage; and cash proceeds received from the settlement of bank-owned life insurance policies should be classified as cash inflows from investing activities while the cash payments for premiums on bank-owned policies may be classified as cash outflows for investing activities, operating activities, or a combination of investing and operating activities. The amendments in this Update are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The amendments in this Update should be applied using a retrospective transition method to each period presented. If it is impracticable to apply the amendments retrospectively for some of the issues, the amendments for those issues would be applied prospectively as of the earliest date practicable. The Company is currently evaluating the impact the adoption of the standard will have on the Company’s statement of cash flows.

Other Real Estate Owned (OREO)

Other Real Estate Owned (OREO) [Text Block]	9 Months Ended
	Sep. 30, 2016
Other Real Estate Owned (OREO) [Text Block]	NOTE 8—OTHER REAL ESTATE OWNED (“OREO”) OREO comprises foreclosed assets acquired in settlement of loans and is carried at fair value less estimated cost to sell and is included in other assets on the Consolidated Balance Sheet. At September 30, 2016 and December 31, 2015, there was $1.2 million and $1.4 million of OREO, respectively. As of September 30, 2016, there were no formal foreclosures proceedings.

Subsequent Events _Text Block_

Subsequent Events [Text Block]	9 Months Ended
	Sep. 30, 2016
Subsequent Events [Text Block]	NOTE 9—PROPOSED ACQUISITION OF LIBERTY BANK, N.A. On July 28, 2016 Middlefield Banc Corp. and Liberty Bank, N.A. entered into an Agreement and Plan of Reorganization. Under the agreement Liberty Bank, N.A. will merge into The Middlefield Banking Company. Of the total merger consideration payable to shareholders of Liberty Bank, N.A., the merger agreement provides that 45% will consist of Middlefield Banc Corp. common stock and the remainder will be cash, for cash of approximately $37.96 per share or Middlefield Banc Corp. common stock at a fixed ratio of 1.1934 for each share of Liberty Bank, N.A. stock exchanged for Middlefield Banc Corp. stock. Liberty Bank, N.A.’s outstanding equity-based awards will be surrendered for total cash currently estimated at approximately $1.147 million. The merger agreement also provides that Liberty Bank, N.A. will pay to its shareholders before merger closing a special dividend in an amount of approximately $3.0 million, subject to possible upward adjustment. Middlefield Banc Corp. owns 23,218 shares of Liberty Bank, N.A. stock, or approximately 2.4%. Those shares will be cancelled in the merger for no consideration.

Summary of Significant Accoun33

Summary of Significant Accounting Policies (Policies)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Basis of Accounting, Policy [Policy Text Block]		Nature of Operations and Basis of Presentation Middlefield Banc Corp. (the “Company”) is an Ohio corporation organized to become the holding company of The Middlefield Banking Company (“MBC”). MBC is a state-chartered bank located in Ohio. On April 19, 2007, Middlefield Banc Corp. acquired Emerald Bank (“EB”), an Ohio-chartered commercial bank headquartered in Dublin, Ohio. EB merged into MBC on January 20, 2014. On October 23, 2009, the Company established an asset resolution subsidiary named EMORECO, Inc. The Company and its subsidiaries derive substantially all of their income from banking and bank-related services, which includes interest earnings on residential real estate, commercial mortgage, commercial and consumer financings as well as interest earnings on investment securities and deposit services to its customers through ten locations. The Company is supervised by the Board of Governors of the Federal Reserve System, while MBC is subject to regulation and supervision by the Federal Deposit Insurance Corporation and the Ohio Division of Financial Institutions. The consolidated financial statements of the Company include its wholly owned subsidiaries, MBC and EMORECO, Inc. Significant intercompany items have been eliminated in preparing the consolidated financial statements. The financial statements have been prepared in conformity with U.S. Generally Accepted Accounting Principles. In preparing the financial statements, management is required to make estimates and assumptions that affect the reported amounts of assets and liabilities as of the balance sheet date and revenues and expenses for the period. Actual results could differ from those estimates.
Marketable Securities, Policy [Policy Text Block]		Investment Securities Investment securities are classified at the time of purchase, based on management’s intention and ability, as securities held to maturity or securities available for sale. Debt securities acquired with the intent and ability to hold to maturity are stated at cost adjusted for amortization of premium and accretion of discount, which are computed using a level yield method and recognized as adjustments of interest income. Certain other debt securities have been classified as available for sale to serve principally as a source of liquidity. Unrealized holding gains and losses for available-for-sale securities are reported as a separate component of stockholders’ equity, net of tax, until realized. Realized security gains and losses are computed using the specific identification method. Interest and dividends on investment securities are recognized as income when earned. Securities are evaluated on at least a quarterly basis and more frequently when economic or market conditions warrant such an evaluation to determine whether a decline in their value is other than temporary. For debt securities, management considers whether the present value of cash flows expected to be collected are less than the security’s amortized cost basis (the difference defined as the credit loss), the magnitude and duration of the decline, the reasons underlying the decline and the Bank’s intent to sell the security or whether it is more likely than not that the Bank would be required to sell the security before its anticipated recovery in market value, to determine whether the loss in value is other than temporary. Once a decline in value is determined to be other than temporary, if the Bank does not intend to sell the security, and it is more likely than not that it will not be required to sell the security, before recovery of the security’s amortized cost basis, the charge to earnings is limited to the amount of credit loss. Any remaining difference between fair value and amortized cost (the difference defined as the non-credit portion) is recognized in other comprehensive income, net of applicable taxes. Otherwise, the entire difference between fair value and amortized cost is charged to earnings. For equity securities where the fair value has been significantly below cost for one year, the Bank’s policy is to recognize an impairment loss unless sufficient evidence is available that the decline is not other than temporary and a recovery period can be predicted.
Cost Method Investments, Policy [Policy Text Block]		Restricted Stock Common stock of the Federal Home Loan Bank (“FHLB”) represents ownership in an institution that is wholly owned by other financial institutions. This equity security is accounted for at cost and classified with other assets. The FHLB of Cincinnati has reported profits for 2015 and 2014, remains in compliance with regulatory capital and liquidity requirements, and continues to pay dividends on the stock and make redemptions at the par value. With consideration given to these factors, management concluded that the stock was not impaired at December 31, 2015 or 2014.
Loans and Leases Receivable, Mortgage Banking Activities, Policy [Policy Text Block]		Mortgage Banking Activities Mortgage loans originated and intended for sale in the secondary market are carried at fair value. The Bank sells the loans on a servicing retained basis. Servicing rights are initially recorded at fair value with the income statement effect recorded in gains on sales of loans. The Bank measures servicing assets using the amortization method. Fair value is based on market prices for comparable mortgage servicing contracts, when available, or alternatively, is based on a valuation model that calculates the present value of estimated future net servicing income. Loan servicing rights are amortized in proportion to and over the period of estimated net future servicing revenue. The expected period of the estimated net servicing income is based in part on the expected prepayment of the underlying mortgages. The unamortized balance of mortgage servicing rights is included in accrued interest and other assets on the Consolidated Balance Sheet. Mortgage servicing rights will be periodically evaluated for impairment, beginning in 2016. Impairment represents the excess of amortized cost over its estimated fair value. Impairment is determined by stratifying rights into tranches based on predominant risk characteristics, such as interest rate and original time to maturity. Any impairment is reported as a valuation allowance for an individual tranche. If the Company later determines that all or a portion of the impairment no longer exists for a particular grouping, a reduction of the allowance will be recorded as an increase to income. Servicing fee income is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of outstanding principal and are recorded as income when earned. The amortization of mortgage servicing rights is netted against loan servicing fee income. Late fees and ancillary fees related to loan servicing are not material. The Company is exposed to interest rate risk on loans held for sale and rate-lock loan commitments (“IRLCs”). As market interest rates increase or decrease, the fair value of loans held for sale and rate-lock commitments will decrease or increase. The Company enters into derivative transactions principally to protect against the risk of adverse interest movements affecting the value of the Company’s committed loan sales pipeline. In order to mitigate the risk that a change in interest rates will result in a decrease in value of the Company’s IRLCs in the committed mortgage pipeline or its loans held for sale, the Company enters into mandatory forward loan sales contracts with secondary market participants. Mandatory forward sales contracts and committed loans intended to be held for sale are considered free-standing derivative instruments and changes in fair value are recorded in current period earnings. For committed loans, fair value is measured using current market rates for the associated mortgage loans. For mandatory forward sales contracts, fair value is measured using secondary market pricing.
Finance, Loans and Leases Receivable, Policy [Policy Text Block]		Loans Loans that management has the intent and ability to hold for the foreseeable future or until maturity or payoff generally are reported at their outstanding unpaid principal balances net of the allowance for loan and lease losses. Interest income is recognized as income when earned on the accrual method. The accrual of interest is discontinued on a loan when management believes, after considering economic and business conditions, the borrower’s financial condition is such that collection of interest is doubtful. Interest received on nonaccrual loans is recorded as income or applied against principal according to management’s judgment as to the collectability of such principal. Loan origination fees and certain direct loan origination costs are being deferred and the net amount amortized as an adjustment of the related loan’s yield. Management is amortizing these amounts over the contractual life of the related loans.
Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]		Allowance for Loan and Lease Losses The allowance for loan and lease losses represents the amount which management estimates is adequate to provide for probable loan losses inherent in the loan portfolio. The allowance method is used in providing for loan losses. Accordingly, all loan losses are charged to the allowance, and all recoveries are credited to it. The allowance for loan and lease losses is established through a provision for loan losses which is charged to operations. The provision is based on management’s periodic evaluation of the adequacy of the allowance for loan and lease losses, which encompasses the overall risk characteristics of the various portfolio segments, past experience with losses, the impact of economic conditions on borrowers, and other relevant factors. The estimates used in determining the adequacy of the allowance for loan and lease losses, including the amounts and timing of future cash flows expected on impaired loans, are particularly susceptible to significant change in the near term. A loan is considered impaired when it is probable the borrower will not repay the loan according to the original contractual terms of the loan agreement. Management has determined that first mortgage loans on one-to-four family properties and all consumer loans represent large groups of smaller-balance homogeneous loans that are to be collectively evaluated. Loans that experience insignificant payment delays, which are defined as 90 days or less, generally are not classified as impaired. A loan is not impaired during a period of delay in payment if the Company expects to collect all amounts due, including interest accrued, at the contractual interest rate for the period of delay. All loans identified as impaired are evaluated independently by management. The Company estimates credit losses on impaired loans based on the present value of expected cash flows or the fair value of the underlying collateral if the loan repayment is expected to come from the sale or operation of such collateral. Impaired loans, or portions thereof, are charged off when it is determined a realized loss has occurred. Until such time, an allowance for loan and lease losses is maintained for estimated losses. Cash receipts on impaired loans are applied first to accrued interest receivable unless otherwise required by the loan terms, except when an impaired loan is also a nonaccrual loan, in which case the portion of the payment related to interest is recognized as income. Mortgage loans secured by one-to-four family properties and all consumer loans are large groups of smaller-balance homogeneous loans and are measured for impairment collectively. Management determines the significance of payment delays on a case-by-case basis, taking into consideration all circumstances concerning the loan, the creditworthiness and payment history of the borrower, the length of the payment delay, and the amount of shortfall in relation to the principal and interest owed.
Property, Plant and Equipment, Policy [Policy Text Block]		Premises and Equipment Land is carried at cost. Premises and equipment are stated at cost net of accumulated depreciation. Depreciation is computed on the straight-line method over the estimated useful lives of the assets, which range from 3 to 20 years for furniture, fixtures, and equipment and 3 to 40 years for buildings and leasehold improvements. Expenditures for maintenance and repairs are charged against income as incurred. Costs of major additions and improvements are capitalized.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]		Goodwill The Company accounts for goodwill using a three-step process for testing the impairment of goodwill on at least an annual basis. This approach could cause more volatility in the Company’s reported net income because impairment losses, if any, could occur irregularly and in varying amounts. No impairment of goodwill was recognized in any of the periods presented.
Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]		Intangible Assets Intangible assets include core deposit intangibles, which are a measure of the value of consumer demand and savings deposits acquired in business combinations accounted for as purchases. The core deposit intangibles are being amortized to expense over a 10 year life on a straight-line basis. The recoverability of the carrying value of intangible assets is evaluated on an ongoing basis, and permanent declines in value, if any, are charged to expense.
Life Insurance Corporate or Bank Owned [Policy Text Block]		Bank-Owned Life Insurance (“BOLI”) The Company owns insurance on the lives of a certain group of key employees. The policies were purchased to help offset the increase in the costs of various fringe benefit plans including healthcare. The cash surrender value of these policies is included as an asset on the Consolidated Balance Sheet and any increases in the cash surrender value are recorded as noninterest income on the Consolidated Statement of Income. In the event of the death of an insured individual under these policies, the Company would receive a death benefit, which would be recorded as noninterest income.
Real Estate, Policy [Policy Text Block]		Other Real Estate Owned Real estate properties acquired through foreclosure are initially recorded at fair value at the date of foreclosure, establishing a new cost basis. After foreclosure, management periodically performs valuations and the real estate is carried at the lower of cost or fair value less estimated cost to sell. Revenue and expenses from operations of the properties, gains or losses on sales and additions to the valuation allowance are included in operating results.
Income Tax, Policy [Policy Text Block]		Income Taxes The Company and its subsidiaries file a consolidated federal income tax return. Deferred tax assets and liabilities are reflected at currently enacted income tax rates applicable to the period in which the deferred tax assets or liabilities are expected to be realized or settled. As changes in tax laws or rates are enacted, deferred tax assets and liabilities are adjusted through the provision for income taxes.
Earnings Per Share, Policy [Policy Text Block]		Earnings Per Share The Company provides dual presentation of basic and diluted earnings per share. Basic earnings per share are calculated utilizing net income as reported in the numerator and average shares outstanding in the denominator. The computation of diluted earnings per share differs in that the dilutive effects of any stock options, warrants, and convertible securities are adjusted in the denominator.
Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]		Stock-Based Compensation The Company accounts for stock compensation based on the grant date fair value of all share-based payment awards that are expected to vest, including employee share options to be recognized as employee compensation expense over the requisite service period. For each of the years ended December 31, 2015, 2014, and 2013, the Company recorded no compensation cost related to vested stock options. As of December 31, 2015, there was no unrecognized compensation cost related to unvested stock options. At year ended December 31, 2015, 585 shares of restricted stock were awarded and immediately vested. There were no shares of restricted stock issued in 2014 or 2013. For the years ended December 31, 2015 and 2014, 2,175 and 11,223 options were exercised resulting in net proceeds to the participant of $7,000 and $50,000, respectively.
Cash and Cash Equivalents, Policy [Policy Text Block]		Cash Flow Information The Company has defined cash and cash equivalents as those amounts included in the Consolidated Balance Sheet captions as “Cash and due from banks” and “Federal funds sold” with original maturities of less than 90 days.
Advertising Costs, Policy [Policy Text Block]		Advertising Costs Advertising costs are expensed as incurred.
Reclassification, Policy [Policy Text Block]		Reclassification of Comparative Amounts Certain comparative amounts for prior years have been reclassified to conform to current-year presentations. Such reclassifications did not affect net income or retained earnings.
New Accounting Pronouncements, Policy [Policy Text Block]	Recent Accounting Pronouncements – In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In June 2014, the FASB issued ASU 2014-12, Compensation – Stock Compensation (Topic 718): Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period In August 2015, the FASB issued ASU 2015-14, Revenue from Contracts with Customers Topic 606 In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) In March 2016, the FASB issued ASU 2016-04, Liabilities Extinguishments of Liabilities (Subtopic 405-20). In March 2016, the FASB issued ASU 2016-05, Derivatives and Hedging (Topic 815) . In March 2016, the FASB issued ASU 2016-06, Derivatives and Hedging (Topic 815) In March 2016, the FASB issued ASU 2016-07, Investments Equity Method and Joint Ventures (Topic 323) In March 2016, the FASB issued ASU 2016-08, Revenue from Contracts with Customers (Topic 606). Revenue from Contracts with Customers (Topic 606), Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, In March 2016, the FASB issued ASU 2016-09, Compensation – Stock Compensation (Topic 718) Share-Based Payment In April 2016, the FASB issued ASU 2016-10, Revenue from Contracts with Customers (Topic 606). Revenue from Contracts with Customers (Topic 606) Revenue from Contracts with Customers (Topic 606) Deferral of the Effective Date In May 2016, the FASB issued ASU 2016-11, Revenue Recognition (Topic 605) and Derivative and Hedging (Topic 815), which rescinds SEC paragraphs pursuant to two SEC Staff Announcements at the March 3, 2016, Emerging Issues Task Force meeting. This Update did not have a significant impact on the Company’s financial statements. In May 2016, the FASB issued ASU 2016-12, Revenue from Contracts with Customers (Topic 606), which among other things clarifies the objective of the collectability criterion in Topic 606, as well as certain narrow aspects of Topic 606. The amendments in this Update affect the guidance in ASU 2014-09, Revenue from Contracts with Customers (Topic 606), which is not yet effective. The effective date and transition requirements for the amendments in this Update are the same as the effective date and transition requirements for Topic 606 (and any other Topic amended by Update 2014-09). ASU 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date, defers the effective date of Update 2014-09 by one year. This Update is not expected to have a significant impact on the Company’s financial statements. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses: Measurement of Credit Losses on Financial Instruments (“ASU 2016-13”), which changes the impairment model for most financial assets. This Update is intended to improve financial reporting by requiring timelier recording of credit losses on loans and other financial instruments held by financial institutions and other organizations. The underlying premise of the Update is that financial assets measured at amortized cost should be presented at the net amount expected to be collected, through an allowance for credit losses that is deducted from the amortized cost basis. The allowance for credit losses should reflect management’s current estimate of credit losses that are expected to occur over the remaining life of a financial asset. The income statement will be effected for the measurement of credit losses for newly recognized financial assets, as well as the expected increases or decreases of expected credit losses that have taken place during the period. ASU 2016-13 is effective for annual and interim periods beginning after December 15, 2019, and early adoption is permitted for annual and interim periods beginning after December 15, 2018. With certain exceptions, transition to the new requirements will be through a cumulative effect adjustment to opening retained earnings as of the beginning of the first reporting period in which the guidance is adopted. The Company is currently evaluating the impact the adoption of the standard will have on the Company’s financial position or results of operations. In August 2016, the FASB issued ASU 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments (“ASU 2016-15”), which addresses eight specific cash flow issues with the objective of reducing diversity in practice. Among these include recognizing cash payments for debt prepayment or debt extinguishment as cash outflows for financing activities; cash proceeds received from the settlement of insurance claims should be classified on the basis of the related insurance coverage; and cash proceeds received from the settlement of bank-owned life insurance policies should be classified as cash inflows from investing activities while the cash payments for premiums on bank-owned policies may be classified as cash outflows for investing activities, operating activities, or a combination of investing and operating activities. The amendments in this Update are effective for public business entities for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. For all other entities, the amendments are effective for fiscal years beginning after December 15, 2018, and interim periods within fiscal years beginning after December 15, 2019. Early adoption is permitted, including adoption in an interim period. If an entity early adopts the amendments in an interim period, any adjustments should be reflected as of the beginning of the fiscal year that includes that interim period. An entity that elects early adoption must adopt all of the amendments in the same period. The amendments in this Update should be applied using a retrospective transition method to each period presented. If it is impracticable to apply the amendments retrospectively for some of the issues, the amendments for those issues would be applied prospectively as of the earliest date practicable. The Company is currently evaluating the impact the adoption of the standard will have on the Company’s statement of cash flows.	Recent Accounting Pronouncements: In January 2014, the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-01, Investments – Equity Method and Joint Ventures (Topic 323): Accounting for Investments in Qualified Affordable Housing Projects. In January 2014, the FASB issued ASU 2014-04, Receivables – Troubled Debt Restructurings by Creditors (Subtopic 310-40): Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans upon Foreclosure. . In May 2014, the FASB issued ASU 2014-09, Revenue from Contracts with Customers In June 2014, the FASB issued ASU 2014-11, Transfers and Servicing (Topic 860): Repurchase-to-Maturity Transactions, Repurchase Financings, and Disclosures In June 2014, the FASB issued ASU 2014-12, Compensation – Stock Compensation (Topic 718 ): Accounting for Share-Based Payments when the Terms of an Award Provide that a Performance Target Could Be Achieved After the Requisite Service Period In August 2014, the FASB issued ASU 2014-14, Receivables – Troubled Debt Restructurings by Creditors (Subtopic 310-40) In November 2014, the FASB issued ASU 2014-17, Business Combinations (Topic 805): Pushdown Accounting. In February 2015, the FASB issued ASU 2015-02, Consolidation (Topic 810) In April 2015, the FASB issued ASU 2015-05, Intangibles – Goodwill and Other – Internal-Use Software (Subtopic 350-40) In May 2015, the FASB issued ASU 2015-08 , Business Combinations – Pushdown Accounting – Amendment to SEC Paragraphs Pursuant to Staff Accounting Bulletin No. 115 In June 2015, the FASB issued ASU 2015-10, Technical Corrections and Improvements In August 2015, the FASB issued ASU 2015-14, Revenue from Contract with Customers Topic 606 In September 2015, the FASB issued ASU 2015-16, Business Combinations (Topic 805). In November 2015, the FASB issued ASU 2015-17, Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes In January 2016, the FASB issued ASU 2016-01, Financial Instruments – Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities

Earnings Per Share _Text Bloc34

Earnings Per Share [Text Block] (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Weighted Average Number of Shares [Table Text Block]	For the Three For the Nine 2016 2015 2016 2015 Weighted-average common shares outstanding 2,633,752 2,253,584 2,445,821 2,248,468 Average treasury stock shares (386,165 ) (189,530 ) (386,165 ) (189,530 ) Weighted-average common shares and common stock equivalents used to calculate basic earnings per share 2,247,587 2,064,054 2,059,656 2,058,938 Additional common stock equivalents (stock options) used to calculate diluted earnings per share 8,643 8,585 8,876 9,254 Weighted-average common shares and common stock equivalents used to calculate diluted earnings per share 2,256,230 2,072,639 2,068,532 2,068,192	2015 2014 2013 Weighted-average common shares outstanding 2,251,365 2,231,165 2,206,392 Average treasury stock shares (236,399 ) (189,530 ) (189,530 ) Weighted-average common shares and common stock equivalents used to calculate basic earnings per share 2,014,966 2,041,635 2,016,862 Additional common stock equivalents used to calculate diluted earnings per share 9,154 7,871 7,178 Weighted-average common shares and common stock equivalents used to calculate diluted earnings per share 2,024,120 2,049,506 2,024,040

Investments in Debt and Marke35

Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities Reconciliation [Table Text Block]	September 30, 2016 (Dollar amounts in thousands) Amortized Gross Gross Fair Value U.S. government agency securities $ 10,516 $ 359 $ (12 ) $ 10,863 Obligations of states and political subdivisions: Taxable 1,616 186 — 1,802 Tax-exempt 81,829 3,899 (5 ) 85,723 Mortgage-backed securities in government-sponsored entities 20,939 485 (44 ) 21,380 Private-label mortgage-backed securities 1,927 141 — 2,068 Total debt securities 116,827 5,070 (61 ) 121,836 Equity securities in financial institutions 750 468 — 1,218 Total $ 117,577 $ 5,538 $ (61 ) $ 123,054 December 31, 2015 Amortized Gross Gross Fair Value U.S. government agency securities $ 21,655 $ 245 $ (271 ) $ 21,629 Obligations of states and political subdivisions: Taxable 1,989 134 — 2,123 Tax-exempt 91,940 3,402 (175 ) 95,167 Mortgage-backed securities in government-sponsored entities 24,480 316 (272 ) 24,524 Private-label mortgage-backed securities 2,079 184 — 2,263 Total debt securities 142,143 4,281 (718 ) 145,706 Equity securities in financial institutions 750 64 — 814 Total $ 142,893 $ 4,345 $ (718 ) $ 146,520	December 31, 2015 (Dollar amounts in thousands) Amortized Gross Gross Fair Value U.S. government agency securities $ 21,655 $ 245 $ (271 ) $ 21,629 Obligations of states and political subdivisions: Taxable 1,989 134 — 2,123 Tax-exempt 91,940 3,402 (175 ) 95,167 Mortgage-backed securities in government-sponsored entities 24,480 316 (272 ) 24,524 Private-label mortgage-backed securities 2,079 184 — 2,263 Total debt securities 142,143 4,281 (718 ) 145,706 Equity securities in financial institutions 750 64 — 814 Total $ 142,893 $ 4,345 $ (718 ) $ 146,520 December 31, 2014 (Dollar amounts in thousands) Amortized Gross Gross Fair Value U.S. government agency securities $ 23,035 $ 311 $ (450 ) $ 22,896 Obligations of states and political subdivisions: Taxable 2,953 226 — 3,179 Tax-exempt 91,916 3,803 (553 ) 95,166 Mortgage-backed securities in government-sponsored entities 29,150 475 (234 ) 29,391 Private-label mortgage-backed securities 2,672 247 — 2,919 Total debt securities 149,726 5,062 (1,237 ) 153,551 Equity securities in financial institutions 750 33 — 783 Total $ 150,476 $ 5,095 $ (1,237 ) $ 154,334
Investments Classified by Contractual Maturity Date [Table Text Block]	(Dollar amounts in thousands) Amortized Fair Due in one year or less $ 2,842 $ 2,879 Due after one year through five years 9,132 9,500 Due after five years through ten years 12,916 13,510 Due after ten years 91,937 95,947 Total $ 116,827 $ 121,836	(Dollar amounts in thousands) Amortized Fair Value Due in one year or less $ 1,135 $ 1,153 Due after one year through five years 10,790 10,890 Due after five years through ten years 19,172 19,830 Due after ten years 111,042 113,833 Total $ 142,139 $ 145,706
Realized Gain (Loss) on Investments [Table Text Block]	For the Three Months For the Nine Months Ended (Dollar amounts in thousands) 2016 2015 2016 2015 Proceeds from sales $ — $ 11,973 $ 9,115 $ 15,284 Gross realized gains — 233 306 373 Gross realized losses — (22 ) (3 ) (116 )	2015 2014 2013 Proceeds from sales $ 15,686 $ 8,383 $ 25,088 Gross realized gains 440 306 186 Gross realized losses (117 ) (58 ) (175 )
Schedule of Unrealized Loss on Investments [Table Text Block]	September 30, 2016 Less than Twelve Months Total (Dollar amounts in thousands) Fair Gross Fair Gross Fair Gross U.S. government agency securities $ 2,000 $ — $ 1,465 $ (12 ) $ 3,465 $ (12 ) Obligations of states and political subdivisions Tax-exempt 608 — — (5 ) 608 (5 ) Mortgage-backed securities in government-sponsored entities — — 4,709 (44 ) 4,709 (44 ) Private-label mortgage-backed securities 75 — — — 75 — Total $ 2,683 $ — $ 6,174 $ (61 ) $ 8,857 $ (61 ) December 31, 2015 Less than Twelve Months Total Fair Gross Fair Gross Fair Gross U.S. government agency securities $ 3,818 $ (57 ) $ 10,872 $ (214 ) $ 14,690 $ (271 ) Obligations of states and political subdivisions Tax-exempt 1,268 (9 ) 9,394 (166 ) 10,662 (175 ) Mortgage-backed securities in government-sponsored entities 8,725 (86 ) 6,685 (186 ) 15,410 (272 ) Total $ 13,811 $ (152 ) $ 26,951 $ (566 ) $ 40,762 $ (718 )	December 31, 2015 Less than Twelve Twelve Months or Total (Dollar amounts in thousands) Fair Gross Fair Gross Fair Gross U.S. government agency securities $ 3,818 $ (57 ) $ 10,872 $ (214 ) $ 14,690 $ (271 ) Obligations of states and political subdivisions Tax-exempt 1,268 (9 ) 9,394 (166 ) 10,662 (175 ) Mortgage-backed securities in government-sponsored entities 8,725 (86 ) 6,685 (186 ) 15,410 (272 ) Total $ 13,811 $ (152 ) $ 26,951 $ (566 ) $ 40,762 $ (718 ) December 31, 2014 Less than Twelve Twelve Months or Total (Dollar amounts in thousands) Fair Gross Fair Gross Fair Gross U.S. government agency securities $ — $ — $ 15,734 $ (450 ) $ 15,734 $ (450 ) Obligations of states and political subdivisions Tax-exempt 2,406 (10 ) 18,232 (543 ) 20,638 (553 ) Mortgage-backed securities in government-sponsored entities — — 16,774 (234 ) 16,774 (234 ) Total $ 2,406 $ (10 ) $ 50,740 $ (1,227 ) $ 53,146 $ (1,237 )

Loans, Notes, Trade and Other36

Loans, Notes, Trade and Other Receivables Disclosure [Text Block] (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]		2015 2014 Commercial and industrial $ 42,536 $ 34,928 Real estate – construction 22,137 30,296 Real estate – mortgage: Residential 232,478 210,096 Commercial 231,701 190,685 Consumer installment 4,858 4,579 533,710 470,584 Less allowance for loan and lease losses (6,385 ) (6,846 ) Net loans $ 527,325 $ 463,738
Schedule of Financing Receivable by Segment [Table Text Block]		Real Estate- Mortgage December 31, 2015 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 1,808 $ 1,787 $ 3,881 $ 6,199 $ 6 $ 13,681 Collectively evaluated for impairment 40,728 20,350 228,597 225,502 4,852 520,029 Total loans $ 42,536 $ 22,137 $ 232,478 $ 231,701 $ 4,858 $ 533,710 Real estate- Mortgage December 31, 2014 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 1,393 $ 3,296 $ 5,183 $ 4,490 $ 6 $ 14,368 Collectively evaluated for impairment 33,535 27,000 204,913 186,195 4,573 456,216 Total loans $ 34,928 $ 30,296 $ 210,096 $ 190,685 $ 4,579 $ 470,584
Schedule of Credit Losses for Financing Receivables, Current [Table Text Block]		Real Estate- Mortgage December 31, 2015 Commercial and Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 388 $ 130 $ 276 $ 39 $ — $ 833 Collectively evaluated for impairment 479 146 2,863 2,039 25 5,552 Total ending allowance balance $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Real Estate- Mortgage December 31, 2014 Commercial and Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 83 $ 589 $ 892 $ 30 $ 2 $ 1,596 Collectively evaluated for impairment 559 279 2,811 1,546 55 5,250 Total ending allowance balance $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Commercial Real estate- Real Real estate- Consumer Total ALLL balance at December 31, 2014 $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Charge-offs (280 ) (385 ) (425 ) (92 ) (15 ) (1,197 ) Recoveries 207 — 186 5 23 421 Provision 298 (207 ) (325 ) 589 (40 ) 315 ALLL balance at December 31, 2015 $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Commercial Real estate- Real Real estate- Consumer Total ALLL balance at December 31, 2013 $ 614 $ 576 $ 3,664 $ 2,170 $ 22 $ 7,046 Charge-offs (237 ) — (671 ) (260 ) (44 ) (1,212 ) Recoveries 121 60 267 40 154 642 Provision 144 232 443 (374 ) (75 ) 370 ALLL balance at December 31, 2014 $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Commercial Real estate- Real Real estate- Consumer Total ALLL balance at December 31, 2012 $ 1,732 $ 1,123 $ 2,872 $ 1,991 $ 61 $ 7,779 Charge-offs (419 ) (191 ) (675 ) — (45 ) (1,330 ) Recoveries 191 33 107 46 24 401 Provision (890 ) (389 ) 1,360 133 (18 ) 196 ALLL balance at December 31, 2013 $ 614 $ 576 $ 3,664 $ 2,170 $ 22 $ 7,046
Impaired Financing Receivables [Table Text Block]		December 31, 2015 Impaired Loans Recorded Unpaid Principal Related With no related allowance recorded: Commercial and industrial $ 1,027 $ 1,025 $ — Real estate – construction 1,657 1,651 — Real estate – mortgage: Residential 2,445 2,443 — Commercial 2,337 2,335 — Total $ 7,466 $ 7,454 $ — With an allowance recorded: Commercial and industrial $ 781 $ 781 $ 388 Real estate – construction 130 130 130 Real estate – mortgage: Residential 1,436 1,436 276 Commercial 3,862 3,846 39 Consumer installment 6 6 — Total $ 6,215 $ 6,199 $ 833 Total: Commercial and industrial $ 1,808 $ 1,806 $ 388 Real estate – construction 1,787 1,781 130 Real estate – mortgage: Residential 3,881 3,879 276 Commercial 6,199 6,181 39 Consumer installment 6 6 — Total $ 13,681 $ 13,653 $ 833 December 31, 2014 Impaired Loans Recorded Unpaid Principal Related With no related allowance recorded: Commercial and industrial $ 1,146 $ 1,145 $ — Real estate – construction 2,707 2,705 — Real estate – mortgage: Residential 2,202 2,197 — Commercial 4,064 4,060 — Total $ 10,119 $ 10,107 $ — With an allowance recorded: Commercial and industrial $ 247 $ 247 $ 83 Real estate – construction 589 589 589 Real estate – mortgage: Residential 2,981 2,978 892 Commercial 426 426 30 Consumer installment 6 6 2 Total $ 4,249 $ 4,246 $ 1,596 Total: Commercial and industrial $ 1,393 $ 1,392 $ 83 Real estate – construction 3,296 3,294 589 Real estate – mortgage: Residential 5,183 5,175 892 Commercial 4,490 4,486 30 Consumer installment 6 6 2 Total $ 14,368 $ 14,353 $ 1,596
Schedule of Additional Information Related to Impaired Loans [Table Text Block]		As of December 31, 2015 As of December 31, 2014 As of December 31, 2013 Average Interest Average Interest Average Interest Commercial and industrial $ 1,468 $ 100 $ 1,989 $ 85 $ 2,187 $ 119 Real estate – construction 2,407 115 3,631 154 3,743 183 Real estate – mortgage: Residential 4,356 160 5,331 171 5,380 293 Commercial 5,203 350 5,998 229 6,500 493 Consumer installment 6 — 11 1 13 1 Total $ 13,440 $ 725 $ 16,960 $ 640 $ 17,824 $ 1,090
Troubled Debt Restructurings on Financing Receivables [Table Text Block]		December 31, 2015 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 6 — 6 $ 434 $ 434 Real estate construction 1 — 1 181 181 Residential real estate 5 1 6 515 535 Commercial real estate 1 — 1 270 270 December 31, 2014 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Residential real estate 3 — 3 $ 140 $ 140 Commercial real estate 1 — 1 48 48 Consumer 1 — 1 6 6 December 31, 2013 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 6 1 7 $ 1,264 $ 1,264 Residential real estate 7 — 7 784 784 Commercial real estate 2 — 2 834 834
Financing Receivable Credit Quality Indicators [Table Text Block]		December 31, 2015 Pass Special Substandard Doubtful Total Commercial and industrial $ 40,560 $ 242 $ 1,734 $ — $ 42,536 Real estate – construction 22,007 — — 130 22,137 Real estate – mortgage: Residential 225,945 728 5,805 — 232,478 Commercial 219,331 4,327 8,043 — 231,701 Consumer installment 4,854 — 4 — 4,858 Total $ 512,697 $ 5,297 $ 15,586 $ 130 $ 533,710 December 31, 2014 Pass Special Substandard Doubtful Total Commercial and industrial $ 33,160 $ — $ 1,730 $ 38 $ 34,928 Real estate – construction 29,212 495 — 589 30,296 Real estate – mortgage: Residential 200,928 584 8,584 — 210,096 Commercial 180,899 3,908 5,878 — 190,685 Consumer installment 4,572 — 7 — 4,579 Total $ 448,759 $ 4,987 $ 16,211 $ 627 $ 470,584
Past Due Financing Receivables [Table Text Block]		December 31, 2015 Current 30-59 Days 60-89 Days 90 Days+ Total Total Commercial and industrial $ 41,544 $ 225 $ 26 $ 741 $ 992 $ 42,536 Real estate – construction 22,137 — — — — 22,137 Real estate – mortgage: Residential 229,725 1,482 92 1,179 2,753 232,478 Commercial 230,903 189 — 609 798 231,701 Consumer installment 4,837 16 3 2 21 4,858 Total $ 529,146 $ 1,912 $ 121 $ 2,531 $ 4,564 $ 533,710 December 31, 2014 Current 30-59 Days 60-89 Days 90 Days+ Total Total Commercial and industrial $ 34,480 $ 349 $ 68 $ 31 $ 448 $ 34,928 Real estate – construction 30,296 — — — — 30,296 Real estate – mortgage: Residential 205,753 2,065 363 1,915 4,343 210,096 Commercial 190,088 30 — 567 597 190,685 Consumer installment 4,547 27 3 2 32 4,579 Total $ 465,164 $ 2,471 $ 434 $ 2,515 $ 5,420 $ 470,584
Schedule of Financing Receivables, Non Accrual Status [Table Text Block]		December 31, 2015 Nonaccrual 90+ Day Past Commercial and industrial $ 1,450 $ — Real estate – construction 130 — Real estate – mortgage: Residential 4,122 — Commercial 1,842 — Consumer installment 1 2 Total $ 7,545 $ 2 December 31, 2014 Nonaccrual 90+ Days Past Commercial and industrial $ 365 $ — Real estate – construction 587 — Real estate – mortgage: Residential 5,310 165 Commercial 1,083 — Consumer installment 2 — Total $ 7,347 $ 165
Subsequently Defaulted [Member]
Schedule of Accounts, Notes, Loans and Financing Receivable [Table Text Block]	September 30, December 31, Commercial and industrial $ 59,376 $ 42,536 Real estate – construction 17,633 22,137 Real estate – mortgage: Residential 258,952 232,478 Commercial 245,636 231,701 Consumer installment 4,732 4,858 586,329 533,710 Less: Allowance for loan and lease losses 6,334 6,385 Net loans $ 579,995 $ 527,325
Schedule of Financing Receivable by Segment [Table Text Block]	Real Estate- Mortgage September 30, 2016 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 844 $ 1,093 $ 3,238 $ 6,466 $ 5 $ 11,646 Collectively evaluated for impairment 58,532 16,540 255,714 239,170 4,727 574,683 Total loans $ 59,376 $ 17,633 $ 258,952 $ 245,636 $ 4,732 $ 586,329 Real estate- Mortgage December 31, 2015 Commercial and Real estate- Residential Commercial Consumer Total Loans: Individually evaluated for impairment $ 1,808 $ 1,787 $ 3,881 $ 6,199 $ 6 $ 13,681 Collectively evaluated for impairment 40,728 20,350 228,597 225,502 4,852 520,029 Total loans $ 42,536 $ 22,137 $ 232,478 $ 231,701 $ 4,858 $ 533,710 Real Estate- Mortgage September 30, 2016 Commercial Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 184 $ 17 $ 104 $ 239 $ — 544 Collectively evaluated for impairment 329 121 2,657 2,656 27 5,790 Total ending allowance balance $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Real Estate- Mortgage December 31, 2015 Commercial Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 388 $ 130 $ 276 $ 39 $ — $ 833 Collectively evaluated for impairment 479 146 2,863 2,039 25 5,552 Total ending allowance balance $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385
Schedule of Credit Losses for Financing Receivables, Current [Table Text Block]	Real Estate- Mortgage September 30, 2016 Commercial Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 184 $ 17 $ 104 $ 239 $ — 544 Collectively evaluated for impairment 329 121 2,657 2,656 27 5,790 Total ending allowance balance $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Real Estate- Mortgage Commercial Real estate- Residential Commercial Consumer Total Allowance for loan and lease losses: Ending allowance balance attributable to loans: Individually evaluated for impairment $ 388 $ 130 $ 276 $ 39 $ — $ 833 Collectively evaluated for impairment 479 146 2,863 2,039 25 5,552 Total ending allowance balance $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at December 31, 2015 $ 867 $ 276 $ 3,139 $ 2,078 $ 25 $ 6,385 Charge-offs (197 ) — (394 ) (70 ) (18 ) (679 ) Recoveries 51 — 113 140 9 313 Provision (208 ) (138 ) (97 ) 747 11 315 ALLL balance at September 30, 2016 $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at December 31, 2014 $ 642 $ 868 $ 3,703 $ 1,576 $ 57 $ 6,846 Charge-offs (196 ) (385 ) (425 ) (92 ) (11 ) (1,109 ) Recoveries 186 — 161 5 21 373 Provision (54 ) (149 ) (13 ) 450 (24 ) 210 ALLL balance at September 30, 2015 $ 578 $ 334 $ 3,426 $ 1,939 $ 43 $ 6,320 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at June 30, 2016 $ 484 $ 159 $ 2,788 $ 2,909 $ 26 $ 6,366 Charge-offs (74 ) — (149 ) — (3 ) (226 ) Recoveries 4 — 82 — 3 89 Provision 99 (21 ) 40 (14 ) 1 105 ALLL balance at September 30, 2016 $ 513 $ 138 $ 2,761 $ 2,895 $ 27 $ 6,334 Commercial Real estate- Real estate- Real estate- Consumer Total ALLL balance at June 30, 2015 $ 610 $ 363 $ 3,347 $ 1,978 $ 48 $ 6,346 Charge-offs (100 ) — (124 ) (5 ) — (229 ) Recoveries 5 — 81 5 7 98 Provision 63 (29 ) 122 (39 ) (12 ) 105 ALLL balance at September 30, 2015 $ 578 $ 334 $ 3,426 $ 1,939 $ 43 $ 6,320
Impaired Financing Receivables [Table Text Block]	September 30, 2016 Impaired Loans Recorded Unpaid Related With no related allowance recorded: Commercial and industrial $ 569 $ 569 $ — Real estate – construction 1,076 1,076 — Real estate – mortgage: Residential 2,774 2,771 — Commercial 1,378 1,375 — Consumer installment 5 5 — Total $ 5,802 $ 5,796 $ — With an allowance recorded: Commercial and industrial $ 275 $ 275 $ 184 Real estate – construction 17 17 17 Real estate – mortgage: Residential 464 462 104 Commercial 5,088 5,078 239 Consumer installment — — — Total $ 5,844 $ 5,832 $ 544 Total: Commercial and industrial $ 844 $ 844 $ 184 Real estate – construction 1,093 1,093 17 Real estate – mortgage: Residential 3,238 3,233 104 Commercial 6,466 6,453 239 Consumer installment 5 5 — Total $ 11,646 $ 11,628 $ 544 December 31, 2015 Impaired Loans Recorded Unpaid Related With no related allowance recorded: Commercial and industrial $ 1,027 $ 1,025 $ — Real estate – construction 1,657 1,651 — Real estate – mortgage: Residential 2,445 2,443 — Commercial 2,337 2,335 — Consumer installment 6 6 — Total $ 7,472 $ 7,460 $ — With an allowance recorded: Commercial and industrial $ 781 $ 781 $ 388 Real estate – construction 130 130 130 Real estate – mortgage: Residential 1,436 1,436 276 Commercial 3,862 3,846 39 Consumer installment — — — Total $ 6,209 $ 6,193 $ 833 Total: Commercial and industrial $ 1,808 $ 1,806 $ 388 Real estate – construction 1,787 1,781 130 Real estate – mortgage: Residential 3,881 3,879 276 Commercial 6,199 6,181 39 Consumer installment 6 6 — Total $ 13,681 $ 13,653 $ 833
Schedule of Additional Information Related to Impaired Loans [Table Text Block]	For the Three Months Ended For the Nine Months Ended Average Interest Average Interest Total: Commercial and industrial $ 864 $ 4 $ 1,218 $ 9 Real estate – construction 1,105 3 1,404 22 Real estate – mortgage: Residential 3,389 36 3,660 36 Commercial 7,939 8 7,449 115 Consumer installment 5 — 6 — $ 13,302 $ 51 $ 13,737 $ 182 For the Three Months For the Nine Months Ended Average Interest Average Interest Total: Commercial and industrial $ 1,480 $ 21 $ 1,354 $ 73 Real estate – construction 2,347 28 2,614 94 Real estate – mortgage: Residential 4,195 43 4,514 128 Commercial 5,476 71 4,871 200 Consumer installment 6 — 6 — $ 13,504 $ 163 $ 13,359 $ 495
Troubled Debt Restructurings on Financing Receivables [Table Text Block]	For the Nine Months Ended September 30, 2016 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 2 — 2 $ 169 $ 169 Residential real estate 1 — 1 58 58 Commercial real estate 1 — 1 311 311 Consumer — — — — — For the Three Months Ended September 30, 2015 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 2 — 2 $ 15 $ 15 Real estate construction — — — — — Residential real estate 1 — 1 164 164 Consumer 1 — 1 9 9 For the Nine Months Ended September 30, 2015 Number of Contracts Pre-Modification Post-Modification Troubled Debt Restructurings Term Other Total Commercial and industrial 3 1 4 $ 126 $ 126 Real estate construction 1 — 1 181 181 Residential real estate 2 1 3 398 418 Consumer 1 — 1 9 9 For the Three Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 1 $ 3 Residential real estate 1 58 For the Nine Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 2 $ 273 Real estate construction 1 58 For the Three Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 1 $ 8 Real estate construction — — Consumer 1 8 For the Nine Months Ended Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 3 $ 55 Real estate construction 1 152 Consumer 1 8	December 31, 2015 Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 2 $ 14 Real estate construction 1 130 December 31, 2014 Troubled Debt Restructurings subsequently defaulted Number of Recorded Residential real estate 1 $ 15 December 31, 2013 Troubled Debt Restructurings subsequently defaulted Number of Recorded Commercial and industrial 5 $ 574 Commercial real estate 1 190
Financing Receivable Credit Quality Indicators [Table Text Block]	Pass Special Substandard Doubtful Total September 30, 2016 Commercial and industrial $ 57,954 $ 445 $ 977 $ — $ 59,376 Real estate – construction 17,448 144 24 17 17,633 Real estate – mortgage: Residential 252,783 433 5,736 — 258,952 Commercial 237,916 3,141 4,579 — 245,636 Consumer installment 4,723 — 9 — 4,732 Total $ 570,824 $ 4,163 $ 11,325 $ 17 $ 586,329 Pass Special Substandard Doubtful Total December 31, 2015 Commercial and industrial $ 40,560 $ 242 $ 1,734 $ — $ 42,536 Real estate – construction 22,007 — — 130 22,137 Real estate – mortgage: Residential 225,945 728 5,805 — 232,478 Commercial 219,331 4,327 8,043 — 231,701 Consumer installment 4,854 — 4 — 4,858 Total $ 512,697 $ 5,297 $ 15,586 $ 130 $ 533,710
Past Due Financing Receivables [Table Text Block]	Current 30-59 Days 60-89 Days 90 Days+ Total Total September 30, 2016 Commercial and industrial $ 58,889 $ 59 $ 92 $ 336 $ 487 $ 59,376 Real estate – construction 17,633 — — — — 17,633 Real estate – mortgage: Residential 257,068 1,052 547 285 1,884 258,952 Commercial 244,771 121 — 744 865 245,636 Consumer installment 4,656 76 — — 76 4,732 Total $ 583,017 $ 1,308 $ 639 $ 1,365 $ 3,312 $ 586,329 Current 30-59 Days 60-89 Days 90 Days+ Total Total December 31, 2015 Commercial and industrial $ 41,544 $ 225 $ 26 $ 741 $ 992 $ 42,536 Real estate – construction 22,137 — — — — 22,137 Real estate – mortgage: Residential 229,725 1,482 92 1,179 2,753 232,478 Commercial 230,903 189 — 609 798 231,701 Consumer installment 4,837 16 3 2 21 4,858 Total $ 529,146 $ 1,912 $ 121 $ 2,531 $ 4,564 $ 533,710
Schedule of Financing Receivables, Non Accrual Status [Table Text Block]	September 30, 2016 90+Days Past Due Commercial and industrial $ 920 $ — Real estate – construction 17 — Real estate – mortgage: Residential 3,822 — Commercial 1,730 — Consumer installment — — Total $ 6,490 $ — December 31, 2015 90+Days Past Due Commercial and industrial $ 1,450 $ — Real estate – construction 130 — Real estate – mortgage: Residential 4,122 — Commercial 1,842 — Consumer installment 1 2 Total $ 7,545 $ 2

Property, Plant and Equipment37

Property, Plant and Equipment Disclosure [Text Block] (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Table Text Block]	(Dollar amounts in thousands) 2015 2014 Land and land improvements $ 1,943 $ 1,943 Building and leasehold improvements 11,414 11,133 Furniture, fixtures, and equipment 4,853 4,637 18,210 17,713 Less accumulated depreciation and amortization 8,438 7,733 Total $ 9,772 $ 9,980

Other Assets Disclosure _Text38

Other Assets Disclosure [Text Block] (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Other Assets [Table Text Block]	(Dollar amounts in thousands) 2015 2014 FHLB stock $ 1,887 $ 1,887 Accrued interest on investment securities 1,010 1,005 Accrued interest on loans 1,377 1,090 Deferred tax asset, net 959 1,484 Other 2,244 1,579 Total $ 7,477 $ 7,045

Short-term Debt _Text Block_ (T

Short-term Debt [Text Block] (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Short-term Debt [Table Text Block]	(Dollar amounts in thousands) 2015 2014 Balance at year-end $ 35,825 $ 14,808 Average balance outstanding 11,768 8,379 Maximum month-end balance 35,825 19,970 Weighted-average rate at year-end 1.37 % 0.98 % Weighted-average rate during the year 1.65 % 1.77 %
Schedule of Repurchase Agreements [Table Text Block]	Repurchase Agreements (Sweep) December 31, 2015 December 31, 2014 Repurchase agreements: U.S. Government agency securities $ 1,052 $ 1,090 Mortgage-backed securities in government-sponsored entities 1,877 2,091 $ 2,929 $ 3,181

Other Borrowings _Text Block_ (

Other Borrowings [Text Block] (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Debt [Table Text Block]	(Dollar amounts in thousands) Description Maturity range Weighted- Stated interest from to from to 2015 2014 Fixed-rate amortizing 07/01/17 10/01/28 4.02 % 2.99 % 4.47 % $ 1,691 $ 2,376 Junior subordinated debt 12/21/37 12/21/37 1.95 % 1.90 1.99 8,248 8,248 Total $ 9,939 $ 10,624
Schedule of Maturities of Long-term Debt [Table Text Block]	(Dollar amounts in thousands) Year Ending December 31, Amount Weighted- 2016 502 4.00 % 2017 373 4.00 % 2018 252 4.02 % 2019 155 4.04 % 2020 116 4.04 % Beyond 2020 8,542 1.51 % Total $ 9,939 1.84 %

Other Liabilities (Tables)

Other Liabilities (Tables)	12 Months Ended
	Dec. 31, 2015
Other Liabilities [Table Text Block]	(Dollar amounts in thousands) 2015 2014 Accrued interest payable $ 395 $ 315 Supplemental Executive Retirement Plan 1,091 828 Accrued salary expense 689 609 Other 449 368 Total $ 2,624 $ 2,120

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]	(Dollar amounts in thousands) 2015 2014 2013 Current payable $ 1,004 $ 2,146 $ 1,556 Deferred 558 (154 ) 423 Total provision $ 1,562 $ 1,992 $ 1,979
Schedule of Deferred Tax Assets and Liabilities [Table Text Block]	(Dollar amounts in thousands) 2015 2014 Deferred tax assets: Allowance for loan and lease losses $ 2,171 $ 2,328 Supplemental retirement plan 371 282 Investment security basis adjustment 66 66 Nonaccrual interest income 415 444 Deferred origination fees, net 12 295 OREO adjustments 92 94 Accrued compensation 234 207 Other 23 14 Gross deferred tax assets 3,384 3,730 Deferred tax liabilities: Premises and equipment 514 385 Net unrealized gain on securities 1,233 1,311 FHLB stock dividends 225 225 Intangibles 401 353 Mortgage servicing rights 68 — Other 44 77 Gross deferred tax liabilities 2,485 2,351 Net deferred tax assets $ 899 $ 1,379
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	(Dollar amounts in thousands) 2015 2014 2013 Amount % of Amount % of Amount % of Provision at statutory rate $ 2,866 34.0 % $ 3,119 34.0 % $ 3,062 34.0 % Tax-free income (1,347 ) (15.9 ) (1,187 ) (12.9 ) (1,138 ) (12.6 ) Nondeductible interest expense 34 0.4 37 0.4 45 0.5 Other 9 0.0 23 0.2 10 0.1 Actual tax expense and effective rate $ 1,562 18.5 % $ 1,992 21.7 % $ 1,979 22.0 %

Compensation and Employee Ben43

Compensation and Employee Benefit Plans [Text Block] (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block]		Projected 2016 $ 29,000 2017 23,000 2018 18,000 2019 12,000 2020 10,000 2021 2,000 Total $ 94,000
Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]	2016 Weighted- 2015 Weighted- Outstanding, January 1 31,949 $ 25.03 46,451 $ 27.90 Expired — — (3,639 ) 37.33 Exercised — — (1,025 ) 20.21 Outstanding, September 30 31,949 $ 25.03 41,787 $ 27.27 Exercisable, September 30 31,949 $ 25.03 41,787 $ 27.27	2015 Weighted- 2014 Weighted- Outstanding, January 1 $ 46,451 $ 27.90 $ 58,581 $ 28.38 Expired (10,802 ) 36.93 — — Exercised (2,175 ) 21.31 (11,223 ) 30.45 Forfeited (1,525 ) 33.53 (907 ) 27.35 Outstanding, December 31 $ 31,949 $ 25.03 $ 46,451 $ 27.90 Exercisable, December 31 $ 31,949 $ 25.03 $ 46,451 $ 27.90
Schedule of Other Share-based Compensation, Activity [Table Text Block]		Outstanding Exercisable Grant Date Exercise Shares Contractual Average Shares Average December 10, 2006 40.24 2,625 0.94 40.24 2,625 40.24 May 16, 2007 37.48 1,337 1.37 37.48 1,337 37.48 December 10, 2007 37.00 1,950 1.94 37.00 1,950 37.00 January 2, 2008 36.25 1,337 2.00 36.25 1,337 36.25 November 10, 2008 23.00 16,500 2.86 23.00 16,500 23.00 May 9, 2011 17.55 8,200 5.35 17.55 8,200 17.55 31,949 31,949

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Commitments [Table Text Block]	(Dollar amounts in thousands) 2015 2014 Commitments to extend credit $ 112,134 $ 97,947 Standby letters of credit 4,404 4,514 Total $ 116,538 $ 102,461
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	2016 $ 285 2017 293 2018 294 2019 289 2020 301 Thereafter 2,055 $ 3,517

Regulatory Capital (Tables)

Regulatory Capital (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table Text Block]	As of December 31, 2015 Leverage Tier 1 Risk Common Total Risk The Middlefield Banking Company 9.23 % 12.52 % 12.52 % 13.73 % Middlefield Banc Corp. 8.69 % 12.00 % 12.00 % 13.20 % Adequately capitalized ratio 4.00 % 6.00 % 4.50 % 8.00 % Adequately capitalized ratio plus capital conservation buffer 4.00 % 8.50 % 7.00 % 10.50 % Well-capitalized ratio (Bank only) 5.00 % 8.00 % 6.50 % 10.00 % As of December 31, 2014 Leverage Tier 1 Risk Total Risk The Middlefield Banking Company 9.25 % 12.95 % 14.19 % Middlefield Banc Corp. 9.60 % 13.38 % 14.64 % Adequately capitalized ratio 4.00 % 4.00 % 8.00 %

Fair Value Disclosure Measure46

Fair Value Disclosure Measurements (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets Measured on Recurring Basis	September 30, 2016 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 10,863 $ — $ 10,863 Obligations of states and political subdivisions — 87,525 — 87,525 Mortgage-backed securities in government-sponsored entities — 21,380 — 21,380 Private-label mortgage-backed securities — 2,068 — 2,068 Total debt securities — 121,836 — 121,836 Equity securities in financial institutions 5 1,213 — 1,218 Total $ 5 $ 123,049 $ — $ 123,054 December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 21,629 $ — $ 21,629 Obligations of states and political subdivisions — 97,290 — 97,290 Mortgage-backed securities in government-sponsored entities — 24,524 — 24,524 Private-label mortgage-backed securities — 2,263 — 2,263 Total debt securities — 145,706 — 145,706 Equity securities in financial institutions 5 809 — 814 Total $ 5 $ 146,515 $ — $ 146,520	December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 21,629 $ — $ 21,629 Obligations of states and political subdivisions — 97,290 — 97,290 Mortgage-backed securities in government- sponsored entities — 24,524 — 24,524 Private-label mortgage-backed securities — 2,263 — 2,263 Total debt securities — 145,706 — 145,706 Equity securities in financial institutions — 814 — 814 Total $ — $ 146,520 $ — $ 146,520 December 31, 2014 Level I Level II Level III Total Assets measured on a recurring basis: U.S. government agency securities $ — $ 22,896 $ — $ 22,896 Obligations of states and political subdivisions — 98,345 — 98,345 Mortgage-backed securities in government- sponsored entities — 29,391 — 29,391 Private-label mortgage-backed securities — 2,919 — 2,919 Total debt securities — 153,551 — 153,551 Equity securities in financial institutions — 783 — 783 Total $ — $ 154,334 $ — $ 154,334
Fair Value, Assets and Liabilities Measured on Nonrecurring Basis, Valuation Techniques	September 30, 2016 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a nonrecurring basis: Impaired loans $ — $ — $ 11,102 $ 11,102 Other real estate owned — — 1,205 1,205 December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a nonrecurring basis: Impaired loans $ — $ — $ 12,848 $ 12,848 Other real estate owned — — 1,412 1,412	December 31, 2015 (Dollar amounts in thousands) Level I Level II Level III Total Assets measured on a non-recurring basis: Impaired loans $ — $ — $ 12,848 $ 12,848 Other real estate owned — — 1,412 1,412 December 31, 2014 Level I Level II Level III Total Assets measured on a non-recurring basis: Impaired loans $ — $ — $ 12,772 $ 12,772 Other real estate owned — — 2,590 2,590
Fair Value Inputs, Assets, Quantitative Information	Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Estimate Valuation Techniques Unobservable Input Range (Weighted Average) September 30, 2016 Impaired loans $ 7,743 Discounted cash flow Discount rate 3.1% to 7.0% (5.0%) 3,359 Appraisal of collateral (1) Appraisal adjustments (2) 0.0% to 55.7% (34.6%) Other real estate owned $ 1,205 Appraisal of collateral (1) Appraisal adjustments (2) 0.0% to 10.0% (7.3%) Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Estimate Valuation Techniques Unobservable Input Range (Weighted Average) December 31, 2015 Impaired loans $ 6,867 Discounted cash flow Discount rate 3.1% to 7.9% (5.0%) 5,981 Appraisal of collateral (1) Appraisal adjustments (2) 0.0% to 87.1% (23.3%) Other real estate owned $ 1,412 Appraisal of collateral (1) Appraisal adjustments (2) 0% to 10.0% (7.3%) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of liquidation expenses and other appraisal adjustments are presented as a percent of the appraisal.	Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Valuation Unobservable Range (Weighted Average) December 31, 2015 Impaired loans $ 6,867 Discounted cash flow Discount rate 3.1% to 7.9% (5.0%) 5,981 Appraisal of collateral (1) Appraisal 0.0% to 87.1% (23.3%) Other real estate owned $ 1,412 Appraisal of collateral (1) Appraisal 0.0% to 10.0% (7.3%) Quantitative Information about Level III Fair Value Measurements (Dollar amounts in thousands) Fair Value Valuation Unobservable Range (Weighted Average) December 31, 2014 Impaired loans $ 12,772 Appraisal of collateral (1) Appraisal adjustments (2) 0% to 84.6% (25.5%) Other real estate owned $ 2,590 Appraisal of collateral (1) Appraisal adjustments (2) 0% to 10.0% (7.5%) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable. (2) Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of liquidation expenses and other appraisal adjustments are presented as a percent of the appraisal.
Fair Value, by Balance Sheet Grouping	September 30, 2016 Carrying Level I Level II Level III Total Fair (Dollar amounts in thousands) Financial assets: Cash and cash equivalents $ 23,276 $ 23,276 $ — $ — $ 23,276 Investment securities Available for sale 123,054 5 123,049 — 123,054 Loans held for sale 880 — 880 — 880 Net loans 579,995 — — 586,739 586,739 Bank-owned life insurance 13,438 13,438 — — 13,438 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,526 2,526 — — 2,526 Financial liabilities: Deposits $ 639,342 $ 454,427 $ — $ 188,668 $ 643,095 Short-term borrowings 32,803 32,803 — — 32,803 Other borrowings 9,713 — — 10,003 10,003 Accrued interest payable 391 391 — — 391 December 31, 2015 Carrying Level I Level II Level III Total Fair (Dollar amounts in thousands) Financial assets: Cash and cash equivalents $ 23,750 $ 23,750 $ — $ — $ 23,750 Investment securities Available for sale 146,520 5 146,515 — 146,520 Loans held for sale 1,107 — 1,107 — 1,107 Net loans 527,325 — — 534,021 534,021 Bank-owned life insurance 13,141 13,141 — — 13,141 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,387 2,387 — — 2,387 Financial liabilities: Deposits $ 624,447 $ 433,226 $ — $ 191,747 $ 624,973 Short-term borrowings 35,825 35,825 — — 35,825 Other borrowings 9,939 — 10,063 10,063 Accrued interest payable 395 395 — — 395	December 31, 2015 Carrying Level I Level II Level III Total Fair (in thousands) Financial assets: Cash and cash equivalents $ 23,750 $ 23,750 $ — $ — $ 23,750 Investment securities available for sale 146,520 — 146,520 — 146,520 Loans held for sale 1,107 — 1,107 — 1,107 Net loans 527,325 — — 534,021 534,021 Bank-owned life insurance 13,141 13,141 — — 13,141 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,387 2,387 — — 2,387 Financial liabilities: Deposits $ 624,447 $ 433,226 $ — $ 191,747 $ 624,973 Short-term borrowings 35,825 35,825 — — 35,825 Other borrowings 9,939 — 10,063 10,063 Accrued interest payable 395 395 — — 395 December 31, 2014 Carrying Level I Level II Level III Total Fair (in thousands) Financial assets: Cash and cash equivalents $ 25,639 $ 25,639 $ — $ — $ 25,639 Investment securities available for sale 154,334 — 154,334 — 154,334 Loans held for sale 438 — 438 — 438 Net loans 463,738 — — 475,019 475,019 Bank-owned life insurance 9,092 9,092 — — 9,092 Federal Home Loan Bank stock 1,887 1,887 — — 1,887 Accrued interest receivable 2,095 2,095 — — 2,095 Financial liabilities: Deposits $ 586,112 $ 416,254 $ — $ 170,542 $ 586,796 Short-term borrowings 14,808 14,808 — — 14,808 Other borrowings 10,624 — 10,822 10,822 Accrued interest payable 315 315 — — 315

Accumulated Other Comprehensi47

Accumulated Other Comprehensive Income (Tables)	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Schedule of Accumulated Other Comprehensive Income (Loss)	(Dollars in thousands) Unrealized gains on Balance as of December 31, 2015 $ 2,395 Other comprehensive income before reclassification 1,421 Amount reclassified from accumulated other comprehensive income (200 ) Period change 1,221 Balance at September 30, 2016 $ 3,616 Balance at June 30, 2016 $ 3,879 Other comprehensive income before reclassification (263 ) Amount reclassified from accumulated other comprehensive income — Period change (263 ) Balance at September 30, 2016 $ 3,616 (Dollars in thousands) Unrealized gains on Balance as of December 31, 2014 $ 2,548 Other comprehensive income before reclassification (461 ) Amount reclassified from accumulated other comprehensive income (170 ) Period change (631 ) Balance at September 30, 2015 1,917 Balance as of June 30, 2015 $ 1,122 Other comprehensive loss before reclassification 935 Amount reclassified from accumulated other comprehensive income (140 ) Period change 795 Balance at September 30, 2015 $ 1,917	(Dollars in thousands) Unrealized gains on Balance as of December 31, 2014 $ 2,548 Other comprehensive income before reclassification 60 Amount reclassified from accumulated other comprehensive income (213 ) Period change (153 ) Balance at December 31, 2015 $ 2,395 (Dollars in thousands) Unrealized gains on Balance as of December 31, 2013 ($ 2,237 ) Other comprehensive income before reclassification 4,949 Amount reclassified from accumulated other comprehensive income (164 ) Period change 4,785 Balance at December 31, 2014 $ 2,548 (a) All amounts are net of tax. Amounts in parentheses indicate debits.
Schedule of Amounts Recognized in Other Comprehensive Income (Loss)	(Dollars in thousands) Details about other Amount Reclassified from Accumulated Other Comprehensive Income (a) For the Three Months Ended Affected Line Item Presented September 30, 2016 September 30, 2015 Unrealized gains on available-for-sale securities $ — $ 211 Investment securities gains, net — (71 ) Income taxes $ — $ 140 Net of tax (Dollars in thousands) Details about other Amount Reclassified from Accumulated Other Comprehensive Income (a) Affected Line Item Net Income is Presented September 30, 2016 September 30, 2015 Unrealized gains on available-for-sale securities $ 303 $ 257 Investment securities gains, net (103 ) (87 ) Income taxes $ 200 $ 170 Net of tax (a) Amounts in parentheses indicate debits to net income	(Dollars in thousands) Details about other comprehensive income Amount Reclassified from Affected Line Item in the Statement Unrealized gains on available-for-sale securities $ 323 Investment securities gains, net (110 ) Income taxes $ 213 Net of tax (Dollars in thousands) Details about other comprehensive income Amount Reclassified from Affected Line Item in the Statement Unrealized gains on available-for-sale securities $ 248 Investment securities gains, net (84 ) Income taxes $ 164 Net of tax (a) Amounts in parentheses indicate debits to net income.

Parent Company (Tables)

Parent Company (Tables)	12 Months Ended
	Dec. 31, 2015
Condensed Balance Sheet [Table Text Block]	(Dollar amounts in thousands) December 31, 2015 2014 ASSETS Cash and due from banks $ 1,329 $ 466 Investment securities available for sale 814 783 Investment in nonbank subsidiary 2,418 2,534 Investment in subsidiary bank 73,061 69,514 Other assets 2,475 1,981 TOTAL ASSETS $ 80,097 $ 75,278 LIABILITIES Trust preferred securities $ 8,248 $ 8,248 Short-term borrowings 9,499 3,136 Other liabilities 43 27 TOTAL LIABILITIES 17,790 11,411 STOCKHOLDERS’ EQUITY 62,307 63,867 TOTAL LIABILITIES AND STOCKHOLDERS’ EQUITY $ 80,097 $ 75,278
Condensed Income Statement [Table Text Block]	Year Ended December 31, (Dollar amounts in thousands) 2015 2014 2013 INCOME Dividends from subsidiary bank $ 4,023 $ 3,142 $ 2,198 Other 19 8 5 Total income 4,042 3,150 2,203 EXPENSES Interest expense 290 304 361 Other 860 816 475 Total expenses 1,150 1,120 836 Income before income tax benefit 2,892 2,030 1,367 Income tax benefit (386 ) (378 ) (283 ) Income before equity in undistributed net income of subsidiaries 3,278 2,408 1,650 Equity in undistributed net income of subsidiaries 3,587 4,772 5,378 NET INCOME $ 6,865 $ 7,180 $ 7,028 Comprehensive Income (Loss) $ 6,712 $ 11,965 $ (600 )
Condensed Cash Flow Statement [Table Text Block]	Year Ended December 31, (Dollar amounts in thousands) 2015 2014 2013 OPERATING ACTIVITIES Net income $ 6,865 $ 7,180 $ 7,028 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed net income of Middlefield Banking Company (3,703 ) (4,798 ) (4,884 ) Equity in undistributed net income of Emerald Bank — — (598 ) Equity in undistributed net loss of EMORECO 116 26 104 Stock-based compensation expense 18 10 — Other (503 ) (409 ) (253 ) Net cash provided by operating activities 2,793 2,009 1,397 FINANCING ACTIVITIES Net increase (decrease) in short-term borrowings 6,363 (759 ) (976 ) Purchase of treasury stock (6,784 ) — — Common stock issued — — 74 Stock options exercised (7 ) (50 ) (77 ) Proceeds from dividend reinvestment plan 651 590 736 Cash dividends (2,153 ) (2,121 ) (2,097 ) Net cash used for financing activities (1,930 ) (2,340 ) (2,340 ) Increase (decrease) in cash 863 (331 ) (943 ) CASH AT BEGINNING OF YEAR 466 797 1,740 CASH AT END OF YEAR $ 1,329 $ 466 $ 797

Selected Quarterly Financial 49

Selected Quarterly Financial Data (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Quarterly Financial Information [Table Text Block]	(Dollar amounts in thousands) Three Months Ended March 31, June 30, September 30, December 31, Total interest income $ 7,035 $ 7,066 $ 7,151 $ 7,343 Total interest expense 883 990 959 988 Net interest income 6,152 6,076 6,192 6,355 Provision for loan losses 105 — 105 105 Net interest income after provision for loan losses 6,047 6,076 6,087 6,250 Total noninterest income 796 962 1,108 1,178 Total noninterest expense 4,811 5,217 4,669 5,380 Income before income taxes 2,032 1,821 2,526 2,048 Income taxes 404 316 544 298 Net income $ 1,628 $ 1,505 $ 1,982 $ 1,750 Per share data: Net income Basic $ 0.79 $ 0.73 $ 0.96 $ 0.93 Diluted 0.78 0.73 0.96 0.92 Average shares outstanding: Basic 2,053,660 2,058,986 2,064,054 1,884,484 Diluted 2,062,867 2,068,313 2,072,639 1,893,345 (Dollar amounts in thousands) Three Months Ended March 31, June 30, September 30, December 31, Total interest income $ 6,989 $ 6,919 $ 6,911 $ 7,055 Total interest expense 1,033 1,033 999 1,005 Net interest income 5,956 5,886 5,912 6,050 Provision for loan losses 180 120 70 — Net interest income after provision for loan losses 5,776 5,766 5,842 6,050 Total noninterest income 715 857 990 1,026 Total noninterest expense 4,229 4,598 4,385 4,638 Income before income taxes 2,262 2,025 2,447 2,438 Income taxes 499 414 529 550 Net income $ 1,763 $ 1,611 $ 1,918 $ 1,888 Per share data: Net income Basic $ 0.87 $ 0.79 $ 0.94 $ 0.92 Diluted 0.86 0.79 0.93 0.92 Average shares outstanding: Basic 2,033,480 2,038,026 2,044,124 2,049,536 Diluted 2,039,515 2,044,564 2,052,012 2,059,561

Summary of Significant Accoun50

Summary of Significant Accounting Policies (Detail)	9 Months Ended		12 Months Ended
	Sep. 30, 2016shares	Sep. 30, 2015USD ($)shares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)shares	Dec. 31, 2013USD ($)shares
Number of Branches			10
Goodwill, Impairment Loss			$ 0	$ 0	$ 0
Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options			$ 0
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in Shares) | shares	360,815
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period (in Shares) | shares	0	1,025	2,175	11,223
Payments for Stock Options Exercised		$ (6,000)	$ 7,000	$ 50,000	77,000
Employee Stock Option [Member]
Allocated Share-based Compensation Expense			$ 0	$ 0	$ 0
Restricted Stock [Member]
Stock Issued During Period, Shares, Share-based Compensation, Net of Forfeitures (in Shares) | shares			585	0	0
Core Deposits [Member]
Finite-Lived Intangible Asset, Useful Life			10 years
Minimum [Member] | Furniture, Fixtures, and Equipment [Member]
Property, Plant and Equipment, Useful Life			3 years
Minimum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life			3 years
Maximum [Member] | Furniture, Fixtures, and Equipment [Member]
Property, Plant and Equipment, Useful Life			20 years
Maximum [Member] | Building and Building Improvements [Member]
Property, Plant and Equipment, Useful Life			40 years

Earnings Per Share - Shares Use

Earnings Per Share - Shares Used in Calculation of Earnings Per Share (Detail) - shares	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Weighted-average common shares outstanding (in shares)	2,633,752		2,253,584							2,445,821	2,248,468	2,251,365	2,231,165	2,206,392
Average treasury stock shares (in shares)	(386,165)		(189,530)							(386,165)	(189,530)	(236,399)	(189,530)	(189,530)
Weighted-average common shares and common stock equivalents used to calculate basic earnings per share (in shares)	2,247,587	1,884,484	2,064,054	2,058,986	2,053,660	2,049,536	2,044,124	2,038,026	2,033,480	2,059,656	2,058,938	2,014,966	2,041,635	2,016,862
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	8,643		8,585							8,876	9,254	9,154	7,871	7,178
Weighted-average common shares and common stock equivalents used to calculate diluted earnings per share (in shares)	2,256,230	1,893,345	2,072,639	2,068,313	2,062,867	2,059,561	2,052,012	2,044,564	2,039,515	2,068,532	2,068,192	2,024,120	2,049,506	2,024,040

Earnings Per Share (Textual) (D

Earnings Per Share (Textual) (Detail) - $ / shares	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	31,949	41,787	31,949	41,787	31,949	46,451	58,581
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	8,643	8,585	8,876	9,254	9,154	7,871	7,178
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number	31,949	42,437	31,949	42,437	31,949	46,451	58,581
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit	$ 17.55	$ 17.55	$ 17.55	$ 17.55	$ 17.55	$ 17.55	$ 17.55
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit	$ 40.24	$ 37.48	$ 40.24	$ 37.48	$ 40.24	$ 40.24	$ 40.24
Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements	24,700	27,000	24,700	27,250	27,250	28,282	39,808

Investment Securities Available

Investment Securities Available for Sale - Amortized Cost and Fair Values of Securities Available for Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Amortized cost	$ 117,577	$ 142,893	$ 150,476
Gross unrealized gains	5,538	4,345	5,095
Gross unrealized losses	(61)	(718)	(1,237)
Investment securities available for sale, at fair value	123,054	146,520	154,334
US Government Agencies Debt Securities [Member]
Amortized cost	10,516	21,655	23,035
Gross unrealized gains	359	245	311
Gross unrealized losses	(12)	(271)	(450)
Investment securities available for sale, at fair value	10,863	21,629	22,896
US States and Political Subdivisions Debt Securities [Member] | Taxable [Member]
Amortized cost	1,616	1,989	2,953
Gross unrealized gains	186	134	226
Gross unrealized losses
Investment securities available for sale, at fair value	1,802	2,123	3,179
US States and Political Subdivisions Debt Securities [Member] | Tax Exempt [Member]
Amortized cost	81,829	91,940	91,916
Gross unrealized gains	3,899	3,402	3,803
Gross unrealized losses	(5)	(175)	(553)
Investment securities available for sale, at fair value	85,723	95,167	95,166
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Amortized cost	20,939	24,480	29,150
Gross unrealized gains	485	316	475
Gross unrealized losses	(44)	(272)	(234)
Investment securities available for sale, at fair value	21,380	24,524	29,391
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Amortized cost	1,927	2,079	2,672
Gross unrealized gains	141	184	247
Gross unrealized losses
Investment securities available for sale, at fair value	2,068	2,263	2,919
Debt Securities [Member]
Amortized cost	116,827	142,143	149,726
Gross unrealized gains	5,070	4,281	5,062
Gross unrealized losses	(61)	(718)	(1,237)
Investment securities available for sale, at fair value	121,836	145,706	153,551
Equity Securities In Financial Institutions [Member]
Amortized cost	750	750	750
Gross unrealized gains	468	64	33
Gross unrealized losses
Investment securities available for sale, at fair value	$ 1,218	$ 814	$ 783

Investment Securities Availab54

Investment Securities Available for Sale - Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Due in one year or less	$ 2,842	$ 1,135
Due after one year through five years	9,132	10,790
Due after five years through ten years	12,916	19,172
Due after ten years	91,937	111,042
Total	116,827	142,139
Due in one year or less	2,879	1,153
Due after one year through five years	9,500	10,890
Due after five years through ten years	13,510	19,830
Due after ten years	95,947	113,833
Total	$ 121,836	$ 145,706

Investment Securities Availab55

Investment Securities Available for Sale (Detail)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Available-for-sale Securities Pledged as Collateral	$ 64,700,000	$ 68,800,000	$ 61,900,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	9	46
Available-for-sale Securities, Percentage of Portfolio	97.00%	97.90%
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 0	$ 0

Investment Securities Availab56

Investment Securities Available for Sale - Sales of Available for Sale Securities (Detail) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Proceeds from sales	$ 11,973	$ 9,115	$ 15,284	$ 15,686	$ 8,383	$ 25,088
Gross realized gains	233	306	373	440	306	186
Gross realized losses	$ (22)	$ (3)	$ (116)	$ (117)	$ (58)	$ (175)

Investment Securities Availab57

Investment Securities Available for Sale - Gross Unrealized Losses and Fair Value (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Less than Twelve Months, Fair Value	$ 2,683	$ 13,811	$ 2,406
Less than Twelve Months, Gross Unrealized Losses	0	(152)	(10)
Twelve Months or Greater, Fair Value	6,174	26,951	50,740
Twelve Months or Greater, Gross Unrealized Losses	(61)	(566)	(1,227)
Total, Fair Value	8,857	40,762	53,146
Total, Gross Unrealized Losses	(61)	(718)	(1,237)
US Government Agencies Debt Securities [Member]
Less than Twelve Months, Fair Value	2,000	3,818
Less than Twelve Months, Gross Unrealized Losses	0	(57)
Twelve Months or Greater, Fair Value	1,465	10,872	15,734
Twelve Months or Greater, Gross Unrealized Losses	(12)	(214)	(450)
Total, Fair Value	3,465	14,690	15,734
Total, Gross Unrealized Losses	(12)	(271)	(450)
US States and Political Subdivisions Debt Securities [Member] | Tax Exempt [Member]
Less than Twelve Months, Fair Value	608	1,268	2,406
Less than Twelve Months, Gross Unrealized Losses	0	(9)	(10)
Twelve Months or Greater, Fair Value	0	9,394	18,232
Twelve Months or Greater, Gross Unrealized Losses	(5)	(166)	(543)
Total, Fair Value	608	10,662	20,638
Total, Gross Unrealized Losses	(5)	(175)	(553)
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Less than Twelve Months, Fair Value	0	8,725
Less than Twelve Months, Gross Unrealized Losses	0	(86)
Twelve Months or Greater, Fair Value	4,709	6,685	16,774
Twelve Months or Greater, Gross Unrealized Losses	(44)	(186)	(234)
Total, Fair Value	4,709	15,410	16,774
Total, Gross Unrealized Losses	(44)	$ (272)	$ (234)
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Less than Twelve Months, Fair Value	75
Less than Twelve Months, Gross Unrealized Losses	0
Twelve Months or Greater, Fair Value	0
Twelve Months or Greater, Gross Unrealized Losses	0
Total, Fair Value	75
Total, Gross Unrealized Losses	$ 0

Loans and Related Allowance for

Loans and Related Allowance for Loan and Lease Losses - Major Classifications of Net Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable Gross	$ 586,329		$ 533,710			$ 470,584
Less: Allowance for loan and lease losses	6,334	$ 6,366	6,385	$ 6,320	$ 6,346	6,846	$ 7,046	$ 7,779
Net loans	579,995		527,325			463,738
Commercial And Industrial [Member]
Financing Receivable Gross	59,376		42,536			34,928
Less: Allowance for loan and lease losses	513	484	867	578	610	642	614	1,732
Real Estate Construction Porfolio Segment [Member]
Financing Receivable Gross	17,633		22,137			30,296
Less: Allowance for loan and lease losses	138	159	276	334	363	868	576	1,123
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Financing Receivable Gross	258,952		232,478			210,096
Less: Allowance for loan and lease losses	2,761	2,788	3,139	3,426	3,347	3,703	3,664	2,872
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Financing Receivable Gross	245,636		231,701			190,685
Less: Allowance for loan and lease losses	2,895	2,909	2,078	1,939	1,978	1,576	2,170	1,991
Consumer Portfolio Segment [Member]
Financing Receivable Gross	4,732		4,858			4,579
Less: Allowance for loan and lease losses	$ 27	$ 26	$ 25	$ 43	$ 48	$ 57	$ 22	$ 61

Loans and Related Allowance f59

Loans and Related Allowance for Loan and Lease Losses - Primary Segments of the Loan Portfolio (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Individually evaluated for impairment	$ 11,646	$ 13,681	$ 14,368
Collectively evaluated for impairment	574,683	520,029	456,216
Total loans	586,329	533,710	470,584
Commercial And Industrial [Member]
Individually evaluated for impairment	844	1,808	1,393
Collectively evaluated for impairment	58,532	40,728	33,535
Total loans	59,376	42,536	34,928
Real Estate Construction Porfolio Segment [Member]
Individually evaluated for impairment	1,093	1,787	3,296
Collectively evaluated for impairment	16,540	20,350	27,000
Total loans	17,633	22,137	30,296
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Individually evaluated for impairment	3,238	3,881	5,183
Collectively evaluated for impairment	255,714	228,597	204,913
Total loans	258,952	232,478	210,096
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Individually evaluated for impairment	6,466	6,199	4,490
Collectively evaluated for impairment	239,170	225,502	186,195
Total loans	245,636	231,701	190,685
Consumer Portfolio Segment [Member]
Individually evaluated for impairment	5	6	6
Collectively evaluated for impairment	4,727	4,852	4,573
Total loans	$ 4,732	$ 4,858	$ 4,579

Loans and Related Allowance of

Loans and Related Allowance of Loan and Lease Losses - Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Individually evaluated for impairment													$ 544	$ 833	$ 1,596
Collectively evaluated for impairment													5,790	5,552	5,250
Total ending allowance balance	$ 6,366	$ 6,385	$ 6,346	$ 6,846			$ 7,046	$ 6,385	$ 6,846	$ 6,846	$ 7,046	$ 7,779	6,334	6,385	6,846
ALLL balance, period start	6,366	6,320	6,346	6,846			7,046	6,385	6,846	6,846	7,046	7,779
Charge-offs	(226)		(229)					(679)	(1,109)	(1,197)	(1,212)	(1,330)
Recoveries	89		98					313	373	421	642	401
Provision	105	105	105	105	$ 70	$ 120	180	315	210	315	370	196
ALLL balance, period end	6,334	6,385	6,320					6,334	6,320	6,385	6,846	7,046
Commercial And Industrial [Member]
Individually evaluated for impairment													184	388	83
Collectively evaluated for impairment													329	479	559
Total ending allowance balance	484	867	610	642			614	867	642	642	614	1,732	513	867	642
ALLL balance, period start	484	578	610	642			614	867	642	642	614	1,732
Charge-offs	(74)		(100)					(197)	(196)	(280)	(237)	(419)
Recoveries	4		5					51	186	207	121	191
Provision	99		63					(208)	(54)	298	144	(890)
ALLL balance, period end	513	867	578					513	578	867	642	614
Real Estate Construction Porfolio Segment [Member]
Individually evaluated for impairment													17	130	589
Collectively evaluated for impairment													121	146	279
Total ending allowance balance	159	276	363	868			576	276	868	868	576	1,123	138	276	868
ALLL balance, period start	159	334	363	868			576	276	868	868	576	1,123
Charge-offs									(385)	(385)		(191)
Recoveries											60	33
Provision	(21)		(29)					(138)	(149)	(207)	232	(389)
ALLL balance, period end	138	276	334					138	334	276	868	576
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Individually evaluated for impairment													104	276	892
Collectively evaluated for impairment													2,657	2,863	2,811
Total ending allowance balance	2,788	3,139	3,347	3,703			3,664	3,139	3,703	3,703	3,664	2,872	2,761	3,139	3,703
ALLL balance, period start	2,788	3,426	3,347	3,703			3,664	3,139	3,703	3,703	3,664	2,872
Charge-offs	(149)		(124)					(394)	(425)	(425)	(671)	(675)
Recoveries	82		81					113	161	186	267	107
Provision	40		122					(97)	(13)	(325)	443	1,360
ALLL balance, period end	2,761	3,139	3,426					2,761	3,426	3,139	3,703	3,664
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Individually evaluated for impairment													239	39	30
Collectively evaluated for impairment													2,656	2,039	1,546
Total ending allowance balance	2,909	2,078	1,978	1,576			2,170	2,078	1,576	1,576	2,170	1,991	2,895	2,078	1,576
ALLL balance, period start	2,909	1,939	1,978	1,576			2,170	2,078	1,576	1,576	2,170	1,991
Charge-offs			(5)					(70)	(92)	(92)	(260)
Recoveries			5					140	5	5	40	46
Provision	(14)		(39)					747	450	589	(374)	133
ALLL balance, period end	2,895	2,078	1,939					2,895	1,939	2,078	1,576	2,170
Consumer Portfolio Segment [Member]
Individually evaluated for impairment															2
Collectively evaluated for impairment													27	25	55
Total ending allowance balance	26	25	48	57			22	25	57	57	22	61	$ 27	$ 25	$ 57
ALLL balance, period start	26	43	48	$ 57			$ 22	25	57	57	22	61
Charge-offs	(3)							(18)	(11)	(15)	(44)	(45)
Recoveries	3		7					9	21	23	154	24
Provision	1		(12)					11	(24)	(40)	(75)	(18)
ALLL balance, period end	$ 27	$ 25	$ 43					$ 27	$ 43	$ 25	$ 57	$ 22

Loans and Related Allowance f61

Loans and Related Allowance for Loan and Lease Losses (Textual) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Sep. 30, 2016
Number of Days Past Due	90 years
Financing Receivable, Modifications, Recorded Investment	$ 3,100,000	$ 2,900,000
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	259,000	$ 207,000	$ 439,000
Threshold For Loans Evaluated For Impairment [Member]
Loans and Leases Receivable before Fees, Gross	1,000,000			$ 1,000,000
Threshold For Loans Evaluated For Impairment [Member] | Outside Consultant [Member]
Loans and Leases Receivable before Fees, Gross	250,000			250,000
Threshold For Loans Evaluated For Impairment [Member] | Criticized Relationships [Member]
Financing Receivable, Gross	125,000			$ 125,000
Threshold For Loans Evaluated For Impairement [Member]
Notes, Loans and Financing Receivable, Gross, Current	150,000
Real Estate Construction Porfolio Segment [Member]
Financing Receivable, Allowance for Credit Losses, Write-downs	400,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Financing Receivable, Allowance for Credit Losses, Write-downs	$ 300,000
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Increase in Portfolio, Percent	21.50%

Loans and Related Allowance f62

Loans and Related Allowance for Loan and Lease Losses - Impaired Loans by Class (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Recorded investment, with no related allowance	$ 5,802	$ 7,472	$ 10,119
Unpaid principal balance, with no related allowance	5,796	7,460	10,107
Recorded investment, with related allowance	5,844	6,209	4,249
Unpaid principal balance, with related allowance	5,832	6,193	4,246
Related allowance	544	833	1,596
Recorded investment	11,646	13,681	14,368
Unpaid principal balance	11,628	13,653	14,353
Scenario, Previously Reported [Member]
Recorded investment, with no related allowance		7,466
Unpaid principal balance, with no related allowance		7,454
Recorded investment, with related allowance		6,215
Unpaid principal balance, with related allowance		6,199
Commercial And Industrial [Member]
Recorded investment, with no related allowance	569	1,027	1,146
Unpaid principal balance, with no related allowance	569	1,025	1,145
Recorded investment, with related allowance	275	781	247
Unpaid principal balance, with related allowance	275	781	247
Related allowance	184	388	83
Recorded investment	844	1,808	1,393
Unpaid principal balance	844	1,806	1,392
Real Estate Construction Porfolio Segment [Member]
Recorded investment, with no related allowance	1,076	1,657	2,707
Unpaid principal balance, with no related allowance	1,076	1,651	2,705
Recorded investment, with related allowance	17	130	589
Unpaid principal balance, with related allowance	17	130	589
Related allowance	17	130	589
Recorded investment	1,093	1,787	3,296
Unpaid principal balance	1,093	1,781	3,294
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Recorded investment, with no related allowance	2,774	2,445	2,202
Unpaid principal balance, with no related allowance	2,771	2,443	2,197
Recorded investment, with related allowance	464	1,436	2,981
Unpaid principal balance, with related allowance	462	1,436	2,978
Related allowance	104	276	892
Recorded investment	3,238	3,881	5,183
Unpaid principal balance	3,233	3,879	5,175
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Recorded investment, with no related allowance	1,378	2,337	4,064
Unpaid principal balance, with no related allowance	1,375	2,335	4,060
Recorded investment, with related allowance	5,088	3,862	426
Unpaid principal balance, with related allowance	5,078	3,846	426
Related allowance	239	39	30
Recorded investment	6,466	6,199	4,490
Unpaid principal balance	6,453	6,181	4,486
Consumer Portfolio Segment [Member]
Recorded investment, with no related allowance	5	6
Unpaid principal balance, with no related allowance	5	6
Recorded investment, with related allowance		6	6
Unpaid principal balance, with related allowance		6	6
Related allowance			2
Recorded investment	5	6	6
Unpaid principal balance	$ 5	$ 6	$ 6

Loans and Related Allowance f63

Loans and Related Allowance for Loan and Lease Losses - Additional Information on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Average Recorded Investment	$ 13,302	$ 13,504	$ 13,737	$ 13,359	$ 13,440	$ 16,960	$ 17,824
Interest Income Recognized	51	163	182	495	725	640	1,090
Commercial And Industrial [Member]
Average Recorded Investment	864	1,480	1,218	1,354	1,468	1,989	2,187
Interest Income Recognized	4	21	9	73	100	85	119
Real Estate Construction Porfolio Segment [Member]
Average Recorded Investment	1,105	2,347	1,404	2,614	2,407	3,631	3,743
Interest Income Recognized	3	28	22	94	115	154	183
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Average Recorded Investment	3,389	4,195	3,660	4,514	4,356	5,331	5,380
Interest Income Recognized	36	43	36	128	160	171	293
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Average Recorded Investment	7,939	5,476	7,449	4,871	5,203	5,998	6,500
Interest Income Recognized	8	71	115	200	350	229	493
Consumer Portfolio Segment [Member]
Average Recorded Investment	5	$ 6	6	$ 6	$ 6	11	13
Interest Income Recognized						$ 1	$ 1

Loans and Related Allowance f64

Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings (Detail) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Commercial And Industrial [Member]
Number of contracts	2	2	4	6		7
Pre-modification outstanding recorded investment	$ 15	$ 169	$ 126	$ 434		$ 1,264
Post-modification outstanding recorded investment	$ 15	$ 169	$ 126	$ 434		$ 1,264
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Number of contracts	1	1	3	6	3	7
Pre-modification outstanding recorded investment	$ 164	$ 58	$ 398	$ 515	$ 140	$ 784
Post-modification outstanding recorded investment	$ 164	$ 58	$ 418	$ 535	$ 140	$ 784
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Number of contracts		1		1	1	2
Pre-modification outstanding recorded investment		$ 311		$ 270	$ 48	$ 834
Post-modification outstanding recorded investment		$ 311		$ 270	$ 48	$ 834
Consumer Portfolio Segment [Member]
Number of contracts	1		1		1
Pre-modification outstanding recorded investment	$ 9		$ 9		$ 6
Post-modification outstanding recorded investment	$ 9		$ 9		$ 6
Real Estate Construction Porfolio Segment [Member]
Number of contracts			1	1
Pre-modification outstanding recorded investment			$ 181	$ 181
Post-modification outstanding recorded investment			$ 181	$ 181
Extended Maturity [Member] | Commercial And Industrial [Member]
Number of contracts	2	2	3	6		6
Extended Maturity [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Number of contracts	1	1	2	5	3	7
Extended Maturity [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Number of contracts		1		1	1	2
Extended Maturity [Member] | Consumer Portfolio Segment [Member]
Number of contracts	1		1		1
Extended Maturity [Member] | Real Estate Construction Porfolio Segment [Member]
Number of contracts			1	1
Other Restructurings [Member] | Commercial And Industrial [Member]
Number of contracts			1			1
Other Restructurings [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Number of contracts			1	1
Other Restructurings [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Number of contracts
Other Restructurings [Member] | Consumer Portfolio Segment [Member]
Number of contracts
Other Restructurings [Member] | Real Estate Construction Porfolio Segment [Member]
Number of contracts

Loans and Related Allowance f65

Loans and Related Allowance for Loan and Lease Losses - Troubled Debt Restructurings Subsequently Defaulted (Detail)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Dec. 31, 2013USD ($)
Commercial And Industrial [Member]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	1	1	2	3	2		5
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 3,000	$ 8,000	$ 273,000	$ 55,000	$ 14,000		$ 574,000
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts	1					1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment	$ 58,000					$ 15,000
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts							1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment							$ 190,000
Real Estate Construction Porfolio Segment [Member]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts			1	1	1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment			$ 58,000	$ 152,000	$ 130,000
Consumer Portfolio Segment [Member]
Financing Receivable, Modifications, Subsequent Default, Number of Contracts		1		1
Financing Receivable, Modifications, Subsequent Default, Recorded Investment		$ 8,000		$ 8,000

Loans and Related Allowance f66

Loans and Related Allowance for Loan and Lease Losses - Classes of the Loan Portfolio Summarized by Credit Quality (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Total loans	$ 586,329	$ 533,710	$ 470,584
Commercial And Industrial [Member]
Total loans	59,376	42,536	34,928
Real Estate Construction Porfolio Segment [Member]
Total loans	17,633	22,137	30,296
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Total loans	258,952	232,478	210,096
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Total loans	245,636	231,701	190,685
Consumer Portfolio Segment [Member]
Total loans	4,732	4,858	4,579
Pass [Member]
Total loans	570,824	512,697	448,759
Pass [Member] | Commercial And Industrial [Member]
Total loans	57,954	40,560	33,160
Pass [Member] | Real Estate Construction Porfolio Segment [Member]
Total loans	17,448	22,007	29,212
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Total loans	252,783	225,945	200,928
Pass [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Total loans	237,916	219,331	180,899
Pass [Member] | Consumer Portfolio Segment [Member]
Total loans	4,723	4,854	4,572
Special Mention [Member]
Total loans	4,163	5,297	4,987
Special Mention [Member] | Commercial And Industrial [Member]
Total loans	445	242
Special Mention [Member] | Real Estate Construction Porfolio Segment [Member]
Total loans	144		495
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Total loans	433	728	584
Special Mention [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Total loans	3,141	4,327	3,908
Substandard [Member]
Total loans	11,325	15,586	16,211
Substandard [Member] | Commercial And Industrial [Member]
Total loans	977	1,734	1,730
Substandard [Member] | Real Estate Construction Porfolio Segment [Member]
Total loans	24
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Total loans	5,736	5,805	8,584
Substandard [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Total loans	4,579	8,043	5,878
Substandard [Member] | Consumer Portfolio Segment [Member]
Total loans	9	4	7
Doubtful [Member]
Total loans	17	130	627
Doubtful [Member] | Commercial And Industrial [Member]
Total loans			38
Doubtful [Member] | Real Estate Construction Porfolio Segment [Member]
Total loans	17	$ 130	$ 589
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Total loans
Doubtful [Member] | Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Total loans

Loans and Related Allowance f67

Loans and Related Allowance for Loan and Lease Losses - Past Due Financing Receivables (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans, current balance	$ 583,017	$ 529,146	$ 465,164
Loans, past due	3,312	4,564	5,420
Total loans	586,329	533,710	470,584
Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	1,308	1,912	2,471
Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	639	121	434
Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	1,365	2,531	2,515
Commercial And Industrial [Member]
Loans, current balance	58,889	41,544	34,480
Loans, past due	487	992	448
Total loans	59,376	42,536	34,928
Commercial And Industrial [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	59	225	349
Commercial And Industrial [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	92	26	68
Commercial And Industrial [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	336	741	31
Real Estate Construction Porfolio Segment [Member]
Loans, current balance	17,633	22,137	30,296
Loans, past due	0
Total loans	17,633	22,137	30,296
Real Estate Construction Porfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	0	0
Real Estate Construction Porfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due	0	0
Real Estate Construction Porfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due	0	0
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, current balance	257,068	229,725	205,753
Loans, past due	1,884	2,753	4,343
Total loans	258,952	232,478	210,096
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, current balance	244,771	230,903	190,088
Loans, past due	865	798	597
Total loans	245,636	231,701	190,685
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Residential Loan [Member]
Loans, past due	1,052	1,482	2,065
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member] | Commercial Loans [Member]
Loans, past due	121	189	30
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Residential Loan [Member]
Loans, past due	547	92	363
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member] | Commercial Loans [Member]
Loans, past due
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Residential Loan [Member]
Loans, past due	285	1,179	1,915
Real Estate Mortgage Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member] | Commercial Loans [Member]
Loans, past due	744	609	567
Consumer Portfolio Segment [Member]
Loans, current balance	4,656	4,837	4,547
Loans, past due	76	21	32
Total loans	4,732	4,858	4,579
Consumer Portfolio Segment [Member] | Financing Receivables, 30 to 59 Days Past Due [Member]
Loans, past due	$ 76	16	27
Consumer Portfolio Segment [Member] | Financing Receivables, 60 to 89 Days Past Due [Member]
Loans, past due		3	3
Consumer Portfolio Segment [Member] | Financing Receivables, Equal to Greater than 90 Days Past Due [Member]
Loans, past due		$ 2	$ 2

Loans and Related Allowance f68

Loans and Related Allowance for Loan and Lease Losses - Classes of the Loan Portfolio Summarized by Nonaccrual Loans and Still Accruing (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans, nonacrrual status	$ 6,490	$ 7,545	$ 7,347
Loans, 90+ days past due and accruing	0	2	165
Commercial And Industrial [Member]
Loans, nonacrrual status	920	1,450	365
Loans, 90+ days past due and accruing	0	0	0
Real Estate Construction Porfolio Segment [Member]
Loans, nonacrrual status	17	130	587
Loans, 90+ days past due and accruing	0	0	0
Real Estate Mortgage Portfolio Segment [Member] | Residential Loan [Member]
Loans, nonacrrual status	3,822	4,122	5,310
Loans, 90+ days past due and accruing	0	0	165
Real Estate Mortgage Portfolio Segment [Member] | Commercial Loans [Member]
Loans, nonacrrual status	1,730	1,842	1,083
Loans, 90+ days past due and accruing	0	0	0
Consumer Portfolio Segment [Member]
Loans, nonacrrual status	0	1	2
Loans, 90+ days past due and accruing	$ 0	$ 2	$ 0

Other Real Estate Owned ("OREO"

Other Real Estate Owned ("OREO") (Textual) (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Real Estate Acquired Through Foreclosure	$ 1.2	$ 1.4	$ 2.6
Mortgage Loans in Process of Foreclosure, Amount		$ 1.1

Premises and Equipment (Details

Premises and Equipment (Details) - Major Classifications of Premises and Equipment (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Major Classifications of Premises and Equipment [Abstract]
Land and land improvements		$ 1,943	$ 1,943
Building and leasehold improvements		11,414	11,133
Furniture, fixtures, and equipment		4,853	4,637
Property, Plant and Equipment, Gross, Total		18,210	17,713
Less accumulated depreciation and amortization		8,438	7,733
Total	$ 9,921	$ 9,772	$ 9,980

Premises and Equipment (Detail)

Premises and Equipment (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Abstract]
Depreciation	$ 715,000	$ 750,000	$ 676,000

Goodwill and Intangible Asset72

Goodwill and Intangible Assets (Detail) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Note 7 - Goodwill and Intangible Assets (Details) [Line Items]
Goodwill	$ 4,559,000		$ 4,559,000		$ 4,559,000	$ 4,559,000
Finite-Lived Core Deposits, Gross					76,000	116,000
Core Deposits [Member]
Note 7 - Goodwill and Intangible Assets (Details) [Line Items]
Finite-Lived Intangible Assets, Accumulated Amortization					$ 320,000	280,000
Finite-Lived Intangible Asset, Useful Life					10 years
Amortization of Intangible Assets	$ 10,000	$ 10,000	$ 30,000	$ 30,000	$ 40,000	$ 40,000	$ 40,000
Finite-Lived Intangible Assets, Amortization Expense, Year Two					40,000
Finite-Lived Intangible Assets, Amortization Expense, Year Three					$ 36,000

Other Assets (Details) - Compon

Other Assets (Details) - Components of Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Note 8 - Other Assets (Details) - Components of Other Assets [Line Items]
FHLB stock	$ 1,887	$ 1,887	$ 1,887
Accrued interest	$ 2,526	2,387	2,095
Deferred tax asset, net		959	1,484
Other		2,244	1,579
Total		7,477	7,045
Investment Securities [Member]
Note 8 - Other Assets (Details) - Components of Other Assets [Line Items]
Accrued interest		1,010	1,005
Loans 1 [Member]
Note 8 - Other Assets (Details) - Components of Other Assets [Line Items]
Accrued interest		$ 1,377	$ 1,090

Deposits (Detail)

Deposits (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Disclosure Text Block [Abstract]
Time Deposit Maturities, Next Twelve Months	$ 92.9
Time Deposit Maturities, Year Two	30.2
Time Deposit Maturities, Year Three	11
Time Deposit Maturities, Year Four	9
Time Deposit Maturities, Year Five	48.2
Time Deposits $250,000 or More	$ 29	$ 54.6

Short-term Borrowings (Details)

Short-term Borrowings (Details) - Outstanding Balances and Related Information of Short-term Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Outstanding Balances and Related Information of Short-term Borrowings [Abstract]
Balance at year-end	$ 35,825	$ 14,808	$ 32,803
Average balance outstanding	11,768	8,379
Maximum month-end balance	$ 35,825	$ 19,970
Weighted-average rate at year-end	1.37%	0.98%
Weighted-average rate during the year	1.65%	1.77%

Short-term Borrowings (Detail)

Short-term Borrowings (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Disclosure Text Block [Abstract]
Line of Credit Facility, Maximum Borrowing Capacity	$ 4	$ 3	$ 2.5
Line of Credit Facility, Interest Rate During Period	3.92%	4.00%	3.75%
Long-term Line of Credit	$ 9.5	$ 3.1	$ 3.9

Short-term Borrowings (Detail77

Short-term Borrowings (Details) - Repurchase Agreements (Detail) - Overnight and Continuous [Member] - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Repurchase agreements:
Repurchase agreements	$ 2,929	$ 3,181
US Government Agencies Debt Securities [Member]
Repurchase agreements:
Repurchase agreements	1,052	1,090
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Repurchase agreements:
Repurchase agreements	$ 1,877	$ 2,091

Other Borrowings (Details) - Ot

Other Borrowings (Details) - Other Borrowings (Detail) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Weighted-average interest rate	1.65%	1.77%
Other borrowings	$ 9,939	$ 10,624	$ 9,713
Fixed Rate Amortizing [Member]
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Maturity range, minimum	Jul. 1, 2017
Maturity range, maximum	Oct. 1, 2028
Weighted-average interest rate	4.02%
Other borrowings	$ 1,691	2,376
Junior Subordinated Debt [Member]
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Maturity range, minimum	Dec. 21, 2037
Maturity range, maximum	Dec. 21, 2037
Weighted-average interest rate	1.95%
Other borrowings	$ 8,248	$ 8,248
Minimum [Member] | Fixed Rate Amortizing [Member]
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Stated interest rate range	2.99%
Minimum [Member] | Junior Subordinated Debt [Member]
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Stated interest rate range	1.90%
Maximum [Member] | Fixed Rate Amortizing [Member]
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Stated interest rate range	4.47%
Maximum [Member] | Junior Subordinated Debt [Member]
Note 11 - Other Borrowings (Details) - Other Borrowings [Line Items]
Stated interest rate range	1.99%

Other Borrowings (Details) - Ma

Other Borrowings (Details) - Maturities of Other Borrowings (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Maturities of Other Borrowings [Abstract]
2,016		$ 502
2,016		4.00%
2,017		$ 373
2,017		4.00%
2,018		$ 252
2,018		4.02%
2,019		$ 155
2,019		4.04%
2,020		$ 116
2,020		4.04%
Beyond 2,020		$ 8,542
Beyond 2,020		1.51%
Total	$ 9,713	$ 9,939	$ 10,624
Total		1.84%

Other Borrowings (Detail)

Other Borrowings (Detail) - USD ($)	1 Months Ended	12 Months Ended
	Dec. 31, 2006	Dec. 31, 2015	Dec. 31, 2013
Note 11 - Other Borrowings (Details) [Line Items]
Annual Paydown of Principal Required		20.00%
Federal Home Loan Bank, Advances, General Debt Obligations, Amount of Available, Unused Funds		$ 80,000,000
Stock Issued During Period, Value, New Issues	$ 248,000		$ 74,000
Notes Payable	$ 8,248,000
London Interbank Offered Rate (LIBOR) [Member]
Note 11 - Other Borrowings (Details) [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.67%
Mandatorily Redeemable Securities [Member] | Special Purpose Entity [Member]
Note 11 - Other Borrowings (Details) [Line Items]
Securities Sold under Agreements to Repurchase	$ 8,000,000

Other Liabilities (Details) - C

Other Liabilities (Details) - Components of Other Liabilities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of Other Liabilities [Abstract]
Accrued interest payable	$ 391	$ 395	$ 315
Supplemental Executive Retirement Plan		1,091	828
Accrued salary expense		689	609
Other		449	368
Total		$ 2,624	$ 2,120

Income Taxes (Details) - The Pr

Income Taxes (Details) - The Provision (Benefit) for Federal Income Taxes (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
The Provision (Benefit) for Federal Income Taxes [Abstract]
Current payable												$ 1,004	$ 2,146	$ 1,556
Deferred										$ 224	$ 397	558	(154)	423
Actual tax expense	$ 261	$ 298	$ 544	$ 316	$ 404	$ 550	$ 529	$ 414	$ 499	$ 1,129	$ 1,264	$ 1,562	$ 1,992	$ 1,979

Income Taxes (Details) - Deferr

Income Taxes (Details) - Deferred Tax Assets and Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred tax assets:
Allowance for loan and lease losses	$ 2,171	$ 2,328
Supplemental retirement plan	371	282
Investment security basis adjustment	66	66
Nonaccrual interest income	415	444
Deferred origination fees, net	12	295
OREO adjustments	92	94
Accrued compensation	234	207
Other	23	14
Gross deferred tax assets	3,384	3,730
Deferred tax liabilities:
Premises and equipment	514	385
Net unrealized gain on securities	1,233	1,311
FHLB stock dividends	225	225
Intangibles	401	353
Mortgage servicing rights	68	0
Other	44	77
Gross deferred tax liabilities	2,485	2,351
Net deferred tax assets	$ 899	$ 1,379

Income Taxes (Detail)

Income Taxes (Detail) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Deferred Tax Assets, Valuation Allowance	$ 0	$ 0
Unrecognized Tax Benefits	$ 0	$ 0

Income Taxes (Details) - Tax Ra

Income Taxes (Details) - Tax Rate Reconciliation (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Tax Rate Reconciliation [Abstract]
Provision at statutory rate												$ 2,866	$ 3,119	$ 3,062
Tax-free income												(1,347)	(1,187)	(1,138)
Nondeductible interest expense												34	37	45
Other												9	23	10
Actual tax expense	$ 261	$ 298	$ 544	$ 316	$ 404	$ 550	$ 529	$ 414	$ 499	$ 1,129	$ 1,264	$ 1,562	$ 1,992	$ 1,979
Provision at statutory rate												34.00%	34.00%	34.00%
Tax-free income												(15.90%)	(12.90%)	(12.60%)
Nondeductible interest expense												0.40%	0.40%	0.50%
Other												0.00%	0.20%	0.10%
Effective rate												18.50%	21.70%	22.00%

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Retirement Plan [Member]
Deferred Compensation Arrangement with Individual, Requisite Service Period	1 year
Defined Contribution Plan, Employer Voluntary Matching, Bank Contribution	50.00%
Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay	6.00%
Defined Contribution Plan, Maximum Annual Contributions Per Employee, Percent	100.00%
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	6 years
Defined Benefit Plan, Contributions by Employer	$ 156,000	$ 143,000	$ 155,000
Retirement Plan [Member] | Middlefield Banking Company [Member]
Defined Contribution Plan Annual Vesting Percentage	20.00%
Directors Retirement Plan [Member] | Middlefield Banking Company [Member]
Deferred Compensation Arrangement with Individual, Requisite Service Period	5 years
Retirement Benefits Term	10 years
Post-retirement Benefits Percentage of Compensation	25.00%
Executive Deferred Compensation Plan [Member] | Middlefield Banking Company [Member]
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 65,000	$ 115,000	$ 120,000

Employee Benefits (Details) - P

Employee Benefits (Details) - Projected Benefit Payments (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Projected Benefit Payments [Abstract]
2,016	$ 29,000
2,017	23,000
2,018	18,000
2,019	12,000
2,020	10,000
2,021	2,000
Total	$ 94,000

Stock-based Compensation (Textu

Stock-based Compensation (Textual) (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Sep. 30, 2016	Sep. 30, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized			$ 0	$ 0
Share-based Compensation Arrangement by Share-based Payment Award, Options, Nonvested, Number of Shares			0	0
Stock Option and Restricted Stock Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized (in Shares)	160,000
Stock Option and Restricted Stock Plan [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Fair Value Assumptions, Expected Term	10 years
Omnibus Equity Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)	0	0

Stock-based Compensation - Stoc

Stock-based Compensation - Stock Option Activity (Detail) - $ / shares	9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Outstanding(in shares)	31,949	46,451	46,451	58,581
Expired (in shares)	0	(3,639)	(10,802)	0
Exercised (in shares)	0	(1,025)	(2,175)	(11,223)
Forfeited (in shares)			(1,525)	(907)
Outstanding (in shares)	31,949	41,787	31,949	46,451
Exercisable (in shares)	31,949	41,787	31,949	46,451
Outstanding (in dollars per share)	$ 25.03	$ 27.90	$ 27.90	$ 28.38
Expired (in dollars per share)	0	37.33	36.93	0
Exercised (in dollars per share)	0	20.21	21.31	30.45
Forfeited (in dollars per share)			33.53	27.35
Outstanding (in dollars per share)	25.03	27.27	25.03	27.90
Exercisable (in dollars per share)	$ 25.03	$ 27.27	$ 25.03	$ 27.90

Employee Benefits - Stocks Opti

Employee Benefits - Stocks Options Outstanding by Grant Date (Detail) - $ / shares	12 Months Ended
	Dec. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013
Outstanding, shares (in Shares)	31,949	31,949	41,787	46,451	58,581
Outstanding, average exercise price	$ 25.03	$ 25.03	$ 27.27	$ 27.90	$ 28.38
Exercisable, shares (in Shares)	31,949	31,949	41,787	46,451
Exercisable, average exercise price	$ 25.03	$ 25.03	$ 27.27	$ 27.90
Granted December 10, 2006 [Member]
Exercise price	$ 40.24
Outstanding, shares (in Shares)	2,625
Outstanding, contractual average life	11 months 9 days
Outstanding, average exercise price	$ 40.24
Exercisable, shares (in Shares)	2,625
Exercisable, average exercise price	$ 40.24
Granted May 16, 2007 [Member]
Exercise price	$ 37.48
Outstanding, shares (in Shares)	1,337
Outstanding, contractual average life	1 year 4 months 13 days
Outstanding, average exercise price	$ 37.48
Exercisable, shares (in Shares)	1,337
Exercisable, average exercise price	$ 37.48
Granted December 10, 2007 [Member]
Exercise price	$ 37
Outstanding, shares (in Shares)	1,950
Outstanding, contractual average life	1 year 11 months 9 days
Outstanding, average exercise price	$ 37
Exercisable, shares (in Shares)	1,950
Exercisable, average exercise price	$ 37
Granted January 2, 2008 [Member]
Exercise price	$ 36.25
Outstanding, shares (in Shares)	1,337
Outstanding, contractual average life	2 years
Outstanding, average exercise price	$ 36.25
Exercisable, shares (in Shares)	1,337
Exercisable, average exercise price	$ 36.25
Granted November 10, 2008 [Member]
Exercise price	$ 23
Outstanding, shares (in Shares)	16,500
Outstanding, contractual average life	2 years 10 months 10 days
Outstanding, average exercise price	$ 23
Exercisable, shares (in Shares)	16,500
Exercisable, average exercise price	$ 23
Granted May 9, 2011 [Member]
Exercise price	$ 17.55
Outstanding, shares (in Shares)	8,200
Outstanding, contractual average life	5 years 4 months 6 days
Outstanding, average exercise price	$ 17.55
Exercisable, shares (in Shares)	8,200
Exercisable, average exercise price	$ 17.55

Commitments (Details) - Outstan

Commitments (Details) - Outstanding Commitments and Contingent Liabilities (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Commitments Contingencies And Litigation [Line Items]
Commitments	$ 116,538	$ 102,461
Commitments to Extend Credit [Member]
Commitments Contingencies And Litigation [Line Items]
Commitments	112,134	97,947
Financial Standby Letter of Credit [Member]
Commitments Contingencies And Litigation [Line Items]
Commitments	$ 4,404	$ 4,514

Commitments - Future Payments U

Commitments - Future Payments Under Operating Leases (Detail) $ in Thousands	Dec. 31, 2015USD ($)
Future Payments Under Operating Leases [Abstract]
2,016	$ 285
2,017	293
2,018	294
2,019	289
2,020	301
Thereafter	2,055
Operating Leases, Future Minimum Payments Due, Total	$ 3,517

Commitments - Additional Inform

Commitments - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]
Operating Leases, Rent Expense	$ 288,000	$ 269,000	$ 301,000

Regulatory Restrictions (Detail

Regulatory Restrictions (Detail) - USD ($) $ in Millions	75 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Banking and Thrift [Abstract]
Nonperforming Assets Sold	$ 5.8
Reserves Required by Federal Reserve Bank	$ 6.9	$ 6.8
Percent of Common Stock	10.00%
Amount Available for Payment of Dividends	$ 8.5

Regulatory Capital - Additional

Regulatory Capital - Additional Information (Detail)	12 Months Ended
	Dec. 31, 2015	Jan. 01, 2019
Capital Conservation Buffer, Phase in Amount
Capital Conservation Buffer, Phase in Amount	0.625%
Capital Conservation Buffer, Phase-in, Number of years	4 years
Scenario, Forecast [Member]
Capital Conservation Buffer, Phase in Amount
Capital Conservation Buffer, Maximum Percentage		2.50%

Regulatory Capital - Capital Ra

Regulatory Capital - Capital Ratios (Detail)	Dec. 31, 2015	Dec. 31, 2014
Adequately capitalized ratio	4.00%	4.00%
Adequately capitalized ratio plus capital conservation buffer	4.00%
Tier 1 risk based capital, adequately capitalized, ratio	6.00%	4.00%
Adequately capitalized ratio plus capital conservation buffer	8.50%
Common equity tier 1 capital, adequately capitalized, ratio	4.50%
Adequately capitalized ratio plus capital conservation buffer	7.00%
Total risk based capital, adequately capitalized, ratio	8.00%	8.00%
Adequately capitalized ratio plus capital conservation buffer	10.50%
Middlefield Banking Company [Member]
Leverage capital, actual, ratio	9.23%	9.25%
Well-capitalized ratio (Bank only)	5.00%	5.00%
Tier 1 risk based capital, actual, ratio	12.52%	12.95%
Tier 1 risk based capital, well-capitalized, ratio (bank only)	8.00%	6.00%
Tier 1 risk based capital, actual, ratio	12.52%
Common equity tier 1 capital, well-capitalized, ratio (bank only)	6.50%
The Middlefield Banking Company	13.73%	14.19%
Total risk based capital, well-capitalized, ratio (bank only)	10.00%	10.00%
Middlefield Banc Corp [Member]
Leverage capital, actual, ratio	8.69%	9.60%
Tier 1 risk based capital, actual, ratio	12.00%	13.38%
Tier 1 risk based capital, actual, ratio	12.00%
The Middlefield Banking Company	13.20%	14.64%

Fair Value Measurements - Asset

Fair Value Measurements - Assets Measured on a Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities	$ 123,054	$ 146,520	$ 154,334
US Government Agencies Debt Securities [Member]
Available-for-sale Securities	10,863	21,629	22,896
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale Securities	21,380	24,524	29,391
Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale Securities	2,068	2,263	2,919
Debt Securities [Member]
Available-for-sale Securities	121,836	145,706	153,551
Equity Securities In Financial Institutions [Member]
Available-for-sale Securities	1,218	814	783
Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member]
Available-for-sale Securities	10,863	21,629	22,896
Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities	87,525	97,290	98,345
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale Securities	21,380	24,524	29,391
Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale Securities	2,068	2,263	2,919
Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Available-for-sale Securities	121,836	145,706	153,551
Fair Value, Measurements, Recurring [Member] | Equity Securities In Financial Institutions [Member]
Available-for-sale Securities	1,218	814	783
Fair Value, Inputs, Level 1 [Member]
Available-for-sale Securities	5	5
Fair Value, Inputs, Level 1 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities In Financial Institutions [Member]
Available-for-sale Securities	5	5
Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities	123,049	146,515	154,334
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | US Government Agencies Debt Securities [Member]
Available-for-sale Securities	10,863	21,629	22,896
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | US States and Political Subdivisions Debt Securities [Member]
Available-for-sale Securities	87,525	97,290	98,345
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale Securities	21,380	24,524	29,391
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Mortgage-backed Securities, Issued by Private Enterprises [Member]
Available-for-sale Securities	2,068	2,263	2,919
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Debt Securities [Member]
Available-for-sale Securities	121,836	145,706	153,551
Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities In Financial Institutions [Member]
Available-for-sale Securities	$ 1,213	809	$ 783
Scenario, Previously Reported [Member]
Available-for-sale Securities		146,520
Scenario, Previously Reported [Member] | Fair Value, Inputs, Level 2 [Member]
Available-for-sale Securities		146,520
Scenario, Previously Reported [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Measurements, Recurring [Member] | Equity Securities In Financial Institutions [Member]
Available-for-sale Securities		$ 814

Fair Value Measurements - Ass98

Fair Value Measurements - Assets Measured on a Nonrecurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Impaired loans	$ 11,646	$ 13,681	$ 14,368
Other real estate owned	1,200	1,400	2,600
Estimate of Fair Value Measurement [Member]
Impaired loans	11,102	12,848	12,772
Other real estate owned	1,205	1,412	2,590
Fair Value, Inputs, Level 3 [Member] | Fair Value, Measurements, Nonrecurring [Member]
Impaired loans	11,102	12,848	12,772
Other real estate owned	$ 1,205	$ 1,412	$ 2,590

Fair Value Measurements - Addit

Fair Value Measurements - Additional Quantitative Information about Assets Measured at Fair Value on Non-recurring Basis (Detail) - Fair Value, Measurements, Nonrecurring [Member] - Fair Value, Inputs, Level 3 [Member] - USD ($) $ in Thousands		9 Months Ended	12 Months Ended
		Sep. 30, 2016	Dec. 31, 2015		Dec. 31, 2014
Impaired Loans [Member] | Income Approach Valuation Technique [Member]
Fair value estimate		$ 7,743	$ 6,867		$ 12,772
Valuation Techniques / Unobservable Input		Discounted cash flow	Discounted cash flow / Discount rate		Appraisal of collateral	[1]
Impaired Loans [Member] | Income Approach Valuation Technique [Member] | Minimum [Member]
Discount Rate		3.10%	3.10%		0.00%
Impaired Loans [Member] | Income Approach Valuation Technique [Member] | Maximum [Member]
Discount Rate		7.00%	7.90%		84.60%
Impaired Loans [Member] | Income Approach Valuation Technique [Member] | Weighted Average [Member]
Discount Rate		5.00%	5.00%		25.50%
Impaired Loans [Member] | Appraisal Adjustments [Member]
Fair value estimate		$ 3,359	$ 5,981
Valuation Techniques / Unobservable Input	[1]	Appraisal of collateral	Appraisal of collateral / Appraisal adjustments	[2]
Impaired Loans [Member] | Appraisal Adjustments [Member] | Minimum [Member]
Discount Rate		0.00%	0.00%
Impaired Loans [Member] | Appraisal Adjustments [Member] | Maximum [Member]
Discount Rate		55.70%	87.10%
Impaired Loans [Member] | Appraisal Adjustments [Member] | Weighted Average [Member]
Discount Rate		34.60%	23.30%
Other Real Estate Owned [Member]
Fair value estimate					$ 2,590
Valuation Techniques / Unobservable Input	[1]				Appraisal of collateral
Other Real Estate Owned [Member] | Minimum [Member]
Discount Rate					0.00%
Other Real Estate Owned [Member] | Maximum [Member]
Discount Rate					10.00%
Other Real Estate Owned [Member] | Weighted Average [Member]
Discount Rate					7.50%
Other Real Estate Owned [Member] | Appraisal Adjustments [Member]
Fair value estimate		$ 1,205	$ 1,412
Valuation Techniques / Unobservable Input	[2]	Appraisal of collateral / Appraisal adjustment	Appraisal of collateral / Appraisal adjustments	[1]
Other Real Estate Owned [Member] | Appraisal Adjustments [Member] | Minimum [Member]
Discount Rate		0.00%	0.00%
Other Real Estate Owned [Member] | Appraisal Adjustments [Member] | Maximum [Member]
Discount Rate		10.00%	10.00%
Other Real Estate Owned [Member] | Appraisal Adjustments [Member] | Weighted Average [Member]
Discount Rate		7.30%	7.30%
[1]	Fair value is generally determined through independent appraisals of the underlying collateral, which generally include various level 3 inputs which are not identifiable.
[2]	Appraisals may be adjusted by management for qualitative factors such as economic conditions and estimated liquidation expenses. The range and weighted average of liquidation expenses and other appraisal adjustments are presented as a percent of the appraisal.

Fair Value Measurements - Estim

Fair Value Measurements - Estimated Fair Value of the Company's Financial Instruments (Detail) - USD ($)	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash and cash equivalents	$ 23,276,000	$ 23,750,000	$ 23,295,000	$ 25,639,000	$ 26,193,000	$ 45,346,000
Cash and cash equivalents, fair value	23,276,000	23,750,000		25,639,000
Available for sale, fair value	123,054,000	146,520,000		154,334,000
Loans held for sale	880,000	1,107,000		438,000
Loans held for sale, fair value	880,000	1,107,000		438,000
Net loans	579,995,000	527,325,000		463,738,000
Net loans, fair value	586,739,000	534,021,000		475,019,000
Bank-owned life insurance	13,438,000	13,141,000		9,092,000
Federal Home Loan Bank stock	1,887,000	1,887,000		1,887,000
Accrued interest receivable	2,526,000	2,387,000		2,095,000
Deposits	639,342,000	624,447,000		586,112,000
Deposits, fair value	643,095,000	624,973,000		586,796,000
Short-term borrowings	32,803,000	35,825,000		14,808,000
Short-term borrowings, fair value	32,803,000	35,825,000		14,808,000
Other borrowings	9,713,000	9,939,000		10,624,000
Other borrowings, fair value	10,003,000	10,063,000		10,822,000
Accrued interest payable	391,000	395,000		315,000
Scenario, Previously Reported [Member]
Available for sale, fair value		146,520,000
Fair Value, Inputs, Level 1 [Member]
Cash and cash equivalents	23,276,000	23,750,000		25,639,000
Available for sale, fair value	5,000	5,000
Bank-owned life insurance	13,438,000	13,141,000		9,092,000
Federal Home Loan Bank stock	1,887,000	1,887,000		1,887,000
Accrued interest receivable	2,526,000	2,387,000		2,095,000
Deposits	454,427,000	433,226,000		416,254,000
Short-term borrowings	32,803,000	35,825,000		14,808,000
Accrued interest payable	391,000	395,000		315,000
Fair Value, Inputs, Level 2 [Member]
Available for sale, fair value	123,049,000	146,515,000		154,334,000
Loans held for sale	880,000	1,107,000		438,000
Fair Value, Inputs, Level 2 [Member] | Scenario, Previously Reported [Member]
Available for sale, fair value		146,520,000
Fair Value, Inputs, Level 3 [Member]
Available for sale, fair value	0	0
Net loans	586,739,000	534,021,000		475,019,000
Deposits	188,668,000	191,747,000		170,542,000
Other borrowings	$ 10,003,000	$ 10,063,000		$ 10,822,000

Accumulate Other Comprehensive

Accumulate Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income (Loss) by Component, Net of Tax (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Beginning balance	$ 3,879	$ 1,122	$ 2,395	$ 2,548	$ 2,548	$ (2,237)
Other comprehensive income (loss) before reclassification	(263)	935	1,421	(461)	60	4,949
Amount reclassified from accumulated other comprehensive income		(140)	(200)	(170)	(213)	(164)
Period change	(263)	795	1,221	(631)	(153)	4,785	$ (7,628)
Ending balance	$ 3,616	$ 1,917	$ 3,616	$ 1,917	$ 2,395	$ 2,548	$ (2,237)

Accumulated Other Comprehens102

Accumulated Other Comprehensive Income - Significant Amounts Reclassified out of Each Component of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Thousands		3 Months Ended	9 Months Ended		12 Months Ended
		Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014
Unrealized gains on available-for-sale securities	[1]	$ 211	$ 303	$ 257	$ 323	$ 248
Income taxes		(71)	(103)	(87)	(110)	(84)
Net of tax		$ 140	$ 200	$ 170	$ 213	$ 164
[1]	Amounts in parentheses indicate debits to net income.

Parent Company - Condensed Bala

Parent Company - Condensed Balance Sheet (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Cash and due from banks	$ 21,976	$ 22,421	$ 20,846
Investment securities available for sale	123,054	146,520	154,334
Other assets		7,477	7,045
TOTAL ASSETS	762,258	735,139	677,531
LIABILITIES
Short-term borrowings	32,803	35,825	14,808
TOTAL LIABILITIES	684,066	672,835	613,664
STOCKHOLDERS' EQUITY	78,192	62,304	63,867	$ 53,473	$ 55,437
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 762,258	735,139	677,531
Parent Company [Member]
ASSETS
Cash and due from banks		1,329	466
Investment securities available for sale		814	783
Other assets		2,475	1,981
TOTAL ASSETS		80,097	75,278
LIABILITIES
Trust preferred securities		8,248	8,248
Short-term borrowings		9,499	3,136
Other liabilities		43	27
TOTAL LIABILITIES		17,790	11,411
STOCKHOLDERS' EQUITY		62,307	63,867
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY		80,097	75,278
Parent Company [Member] | Non Bank Subsidiary [Member]
ASSETS
Equity method investments		2,418	2,534
Parent Company [Member] | Subsidiary Banks [Member]
ASSETS
Equity method investments		$ 73,061	$ 69,514

Parent Company - Condensed Stat

Parent Company - Condensed Statement of Income and Comprehensive Income (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
INCOME
Total income	$ 7,420		$ 7,151							$ 22,173	$ 21,252	$ 28,595	$ 27,874	$ 28,178
EXPENSES
Interest expense	1,026	$ 988	959	$ 990	$ 883	$ 1,005	$ 999	$ 1,033	$ 1,033	3,117	2,832	3,820	4,070	5,250
Income before income tax benefit	1,604	2,048	2,526	1,821	2,032	2,438	2,447	2,025	2,262	5,885	6,379	8,427	9,172	9,007
Income tax benefit	261	298	544	316	404	550	529	414	499	1,129	1,264	1,562	1,992	1,979
NET INCOME	1,343	$ 1,750	1,982	$ 1,505	$ 1,628	$ 1,888	$ 1,918	$ 1,611	$ 1,763	4,756	5,115	6,865	7,180	7,028
Comprehensive Income (Loss)	$ 1,080		$ 2,777							$ 5,977	$ 4,484	6,712	11,965	(600)
Parent Company [Member]
INCOME
Dividends from subsidiary bank												4,023	3,142	2,198
Other												19	8	5
Total income												4,042	3,150	2,203
EXPENSES
Interest expense												290	304	361
Other												860	816	475
Total expenses												1,150	1,120	836
Income before income tax benefit												2,892	2,030	1,367
Income tax benefit												(386)	(378)	(283)
Income before equity in undistributed net income of subsidiaries												3,278	2,408	1,650
Equity in undistributed net income of subsidiaries												3,587	4,772	5,378
NET INCOME												6,865	7,180	7,028
Comprehensive Income (Loss)												$ 6,712	$ 11,965	$ (600)

Parent Company - Condensed S105

Parent Company - Condensed Statement of Cash Flows (Detail) - USD ($) $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
OPERATING ACTIVITIES
Net income	$ 1,343	$ 1,750	$ 1,982	$ 1,505	$ 1,628	$ 1,888	$ 1,918	$ 1,611	$ 1,763	$ 4,756	$ 5,115	$ 6,865	$ 7,180	$ 7,028
Other										253	(158)	121	(831)	263
Net cash provided by operating activities										6,029	5,416	7,182	7,459	9,897
FINANCING ACTIVITIES
Net increase (decrease) in short-term borrowings										(3,022)	(10,761)	21,017	3,999	4,271
Purchase of treasury stock												(6,784)
Common stock issued										11,239				74
Cash dividends										(1,710)	(1,645)	(2,153)	(2,121)	(2,097)
Net cash provided by (used for) financing activities										21,558	28,216	50,374	18,709	(22,953)
Increase (decrease) in cash and cash equivalents										(474)	(2,344)	(1,889)	(554)	(19,153)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD		23,295			25,639				26,193	23,750	25,639	25,639	26,193	45,346
CASH AND CASH EQUIVALENTS AT END OF PERIOD	$ 23,276	23,750	$ 23,295			25,639				23,276	23,295	23,750	25,639	26,193
Parent Company [Member]
OPERATING ACTIVITIES
Net income												6,865	7,180	7,028
Equity method investments, income (loss)												(3,587)	(4,772)	(5,378)
Net cash provided by operating activities												2,793	2,009	1,397
FINANCING ACTIVITIES
Net increase (decrease) in short-term borrowings												6,363	(759)	(976)
Purchase of treasury stock												(6,784)
Common stock issued														74
Stock options exercised												(7)	(50)	(77)
Proceeds from dividend reinvestment plan												651	590	736
Cash dividends												(2,153)	(2,121)	(2,097)
Net cash provided by (used for) financing activities												(1,930)	(2,340)	(2,340)
Increase (decrease) in cash and cash equivalents												863	(331)	(943)
CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD					$ 466				$ 797	$ 1,329	$ 466	466	797	1,740
CASH AND CASH EQUIVALENTS AT END OF PERIOD		$ 1,329				$ 466						1,329	466	797
Parent Company [Member] | Middlefield Banking Company [Member]
OPERATING ACTIVITIES
Equity method investments, income (loss)												(3,703)	(4,798)	(4,884)
Stock-based compensation expense												18	10
Other												(503)	(409)	(253)
Parent Company [Member] | Emerald Bank [Member]
OPERATING ACTIVITIES
Equity method investments, income (loss)														(598)
Parent Company [Member] | EMORECO [Member]
OPERATING ACTIVITIES
Equity method investments, income (loss)												$ 116	$ 26	$ 104

Selected Quarterly Financial106

Selected Quarterly Financial Data - Selected Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended									9 Months Ended		12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Selected Quarterly Financial Data (Unaudited) [Abstract]
Total interest income		$ 7,343	$ 7,151	$ 7,066	$ 7,035	$ 7,055	$ 6,911	$ 6,919	$ 6,989
Total interest expense	$ 1,026	988	959	990	883	1,005	999	1,033	1,033	$ 3,117	$ 2,832	$ 3,820	$ 4,070	$ 5,250
Net interest income	6,394	6,355	6,192	6,076	6,152	6,050	5,912	5,886	5,956	19,056	18,420	24,775	23,804	22,928
Provision for loan losses	105	105	105		105		70	120	180	315	210	315	370	196
NET INTEREST INCOME AFTER PROVISION FOR LOAN LOSSES	6,289	6,250	6,087	6,076	6,047	6,050	5,842	5,766	5,776	18,741	18,210	24,460	23,434	22,732
Total noninterest income	977	1,178	1,108	962	796	1,026	990	857	715	3,059	2,866	4,044	3,588	3,145
Total noninterest expense	5,662	5,380	4,669	5,217	4,811	4,638	4,385	4,598	4,229	15,915	14,697	20,077	17,850	16,870
Income before income taxes	1,604	2,048	2,526	1,821	2,032	2,438	2,447	2,025	2,262	5,885	6,379	8,427	9,172	9,007
Income taxes	261	298	544	316	404	550	529	414	499	1,129	1,264	1,562	1,992	1,979
Net income	$ 1,343	$ 1,750	$ 1,982	$ 1,505	$ 1,628	$ 1,888	$ 1,918	$ 1,611	$ 1,763	$ 4,756	$ 5,115	$ 6,865	$ 7,180	$ 7,028
Net income
Basic (in Dollars per share)	$ 0.60	$ 0.93	$ 0.96	$ 0.73	$ 0.79	$ 0.92	$ 0.94	$ 0.79	$ 0.87	$ 2.31	$ 2.49	$ 3.41	$ 3.52	$ 3.48
Diluted (in dollars per share)	$ 0.60	$ 0.92	$ 0.96	$ 0.73	$ 0.78	$ 0.92	$ 0.93	$ 0.79	$ 0.86	$ 2.31	$ 2.47	$ 3.39	$ 3.50	$ 3.47
Average shares outstanding:
Basic (in Shares)	2,247,587	1,884,484	2,064,054	2,058,986	2,053,660	2,049,536	2,044,124	2,038,026	2,033,480	2,059,656	2,058,938	2,014,966	2,041,635	2,016,862
Diluted (in Shares)	2,256,230	1,893,345	2,072,639	2,068,313	2,062,867	2,059,561	2,052,012	2,044,564	2,039,515	2,068,532	2,068,192	2,024,120	2,049,506	2,024,040

Fair Value Measurements (Textua

Fair Value Measurements (Textual) (Detail) - USD ($)	Sep. 30, 2016	Dec. 31, 2015	Dec. 31, 2014
Available-for-sale Securities	$ 123,054,000	$ 146,520,000	$ 154,334,000
Fair Value, Inputs, Level 3 [Member]
Available-for-sale Securities	$ 0	$ 0

Investment Securities Availa108

Investment Securities Available for Sale (Textual) (Detail)	Sep. 30, 2016USD ($)	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Available-for-sale Securities Pledged as Collateral	$ 64,700,000	$ 68,800,000	$ 61,900,000
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	9	46
Available-for-sale Securities, Percentage of Portfolio	97.00%	97.90%
Other than Temporary Impairment, Credit Losses Recognized in Earnings, Credit Losses on Debt Securities Held	$ 0	$ 0

Subsequent Event (Textual) (Det

Subsequent Event (Textual) (Detail) - Merger of Liberty Bank, N.A. into The Middlefield Banking Company [member] - USD ($) $ / shares in Units, $ in Thousands	2 Months Ended
	Dec. 31, 2016	Jul. 28, 2016
Liberty Bank, N.A. [Member]
Business Combination, Merger Agreement, Special Dividend to Be Paid to Entity's Shareholders Before Merger		$ 3,000
Business Combination, Merger Agreement, Percentage of Merger Consideration to Be Paid in Common Stock		45.00%
Business Combination, Merger Agreement, Cash Per Share of Reporting Entity Common Stock		$ 37.96
Business Combination, Merger Agreement, Ratio of Shares of Reporting Entity's Common Stock for Each Share of Acquired Entity's Common Stock		1.1934
Business Combination, Shares in Acquired Entity Owned Prior to Merger		23,218
Business Combination, Ownership Percentage in Acquired Entity Prior to Merger		2.40%
Scenario, Forecast [Member]
Payments to Acquire Businesses, Gross	$ 1,147