Old Second Bancorp (OSBC) 10-K 13 Mar 18 2017 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Mar. 10, 2018	Jun. 30, 2017
Document and Entity Information
Entity Registrant Name	OLD SECOND BANCORP INC
Entity Central Index Key	357,173
Document Type	10-K
Document Period End Date	Dec. 31, 2017
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Accelerated Filer
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Public Float			$ 336.7
Entity Common Stock, Shares Outstanding		29,693,150
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	FY

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 37,444	$ 33,805
Interest bearing deposits with financial institutions	18,389	13,529
Cash and cash equivalents	55,833	47,334
Securities available-for-sale, at fair value	541,439	531,838
Federal Home Loan Bank and Federal Reserve Bank stock	10,168	7,918
Loans held-for-sale	4,067	4,918
Loans	1,617,622	1,478,809
Less: allowance for loan losses	17,461	16,158
Net loans	1,600,161	1,462,651
Premises and equipment, net	37,628	38,977
Other real estate owned	8,371	11,916
Mortgage servicing rights, net	6,944	6,489
Goodwill and core deposit intangible	8,922	9,018
Bank-owned life insurance (BOLI)	61,764	60,332
Deferred tax assets, net	25,356	53,464
Other assets	22,776	16,333
Total assets	2,383,429	2,251,188
Deposits:
Noninterest bearing demand	572,404	513,688
Interest bearing:
Savings, NOW, and money market	967,750	950,849
Time	382,771	402,248
Total deposits	1,922,925	1,866,785
Securities sold under repurchase agreements	29,918	25,715
Other short-term borrowings	115,000	70,000
Junior subordinated debentures	57,639	57,591
Senior notes	44,058	43,998
Other liabilities	13,539	11,889
Total liabilities	2,183,079	2,075,978
Stockholders' Equity
Common stock	34,626	34,534
Additional paid-in capital	117,742	116,653
Retained earnings	142,959	129,005
Accumulated other comprehensive loss	1,479	(8,762)
Treasury stock	(96,456)	(96,220)
Total stockholders' equity	200,350	175,210
Total liabilities and stockholders' equity	$ 2,383,429	$ 2,251,188

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares	Dec. 31, 2017	Dec. 31, 2016
Consolidated Balance Sheets
Common stock, Par value (in dollars per share)	$ 1	$ 1
Common Stock, Shares authorized	60,000,000	60,000,000
Common stock, Shares issued	34,625,734	34,534,234
Common stock, Shares outstanding	29,627,086	29,556,216
Treasury stock, Shares	4,998,648	4,978,018

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Interest and Dividend Income
Loans, including fees	$ 70,737	$ 56,019	$ 53,035
Loans held-for-sale	123	151	189
Securities:
Taxable	10,202	15,865	14,037
Tax exempt	5,939	842	542
Dividends from Federal Reserve Bank and Federal Home Loan Bank stock	370	333	306
Interest bearing deposits with financial institutions	134	169	55
Total interest and dividend income	87,505	73,379	68,164
Interest Expense
Savings, NOW, and money market deposits	950	789	734
Time deposits	4,227	3,640	3,201
Other short-term borrowings	758	106	33
Junior subordinated debentures	4,002	4,334	4,287
Senior notes	2,689	112
Subordinated debt		949	814
Notes payable and other borrowings		8	7
Total interest expense	12,626	9,938	9,076
Net interest and dividend income	74,879	63,441	59,088
Loan loss reserve release	1,800	750	(4,400)
Net interest and dividend income after release for loan losses	73,079	62,691	63,488
Noninterest Income
Trust income	6,203	5,670	5,953
Service charges on deposits	6,720	6,684	6,820
Secondary mortgage fees	776	1,038	907
Mortgage servicing rights mark to market loss	(802)	(919)	(1,141)
Mortgage servicing gain / (loss), net of changes in fair value	1,778	1,724	1,628
Net gain on sales of mortgage loans	4,803	6,343	5,775
Securities loss, net	474	(2,213)	(178)
Increase in cash surrender value of bank-owned life insurance	1,432	1,283	1,277
Death benefit realized on bank-owned life insurance			115
Debit card interchange income	4,200	4,027	4,028
(Loss) gain on disposal and transfer of fixed assets	10	(1)	(1,119)
Other income	4,778	4,938	5,229
Total noninterest income	30,372	28,574	29,294
Noninterest Expense
Salaries and employee benefits	40,080	36,234	35,061
Occupancy expense, net	5,951	6,063	6,260
Furniture and equipment expense	4,387	4,349	4,357
FDIC insurance	658	865	1,334
General bank insurance	1,031	1,109	1,273
Amortization of core deposit intangible	96	16
Advertising expense	1,505	1,633	1,340
Debit card interchange expense	1,329	1,455	1,514
Legal fees	650	800	1,175
Other real estate expense, net	2,165	2,743	5,191
Other expense	11,297	11,494	10,916
Total noninterest expense	69,149	66,761	68,421
Income before income taxes	34,302	24,504	24,361
Provision for income taxes	19,164	8,820	8,976
Net income	15,138	15,684	15,385
Preferred stock dividends and accretion of discount			1,873
Net income available to common stockholders	$ 15,138	$ 15,684	$ 13,512
Basic earnings per share (in dollars per share)	$ 0.51	$ 0.53	$ 0.46
Diluted earnings per share (in dollars per share)	$ 0.50	$ 0.53	$ 0.46

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Consolidated Statements of Comprehensive Income
Net income	$ 15,138	$ 15,684	$ 15,385
Unrealized holding (losses) gains on available-for-sale securities arising during the period	17,863	(1,155)	(8,624)
Related tax benefit (expense)	(7,183)	445	3,382
Holding (losses) gains after tax on available-for-sale securities	10,680	(710)	(5,242)
Less: Reclassification adjustment for the net (losses) gains realized during the period
Net realized (losses) gains	474	(2,213)	(178)
Income tax benefit (expense) on net realized gains	(198)	882	71
Net realized (losses) gains after tax	276	(1,331)	(107)
Other comprehensive (loss) income on available-for-sale securities	10,404	621	(5,135)
Accretion of net unrealized holding gains on held-to-maturity transferred from available-for-sale securities		5,939	964
Related tax expense		(2,446)	(396)
Other comprehensive income on held-to-maturity securities		3,493	568
Changes in fair value of derivatives used for cashflow hedges	(293)	(363)	(631)
Related tax benefit	130	146	252
Other comprehensive loss on cashflow hedges	(163)	(217)	(379)
Total other comprehensive income (loss) income	10,241	3,897	(4,946)
Total comprehensive income	$ 25,379	$ 19,581	$ 10,439

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash flows from operating activities
Net income	$ 15,138,000	$ 15,684,000	$ 15,385,000
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization of leasehold improvement	2,306,000	2,288,000	2,386,000
Change in fair value of mortgage servicing rights	802,000	919,000	1,141,000
Loan loss reserve release	1,800,000	750,000	(4,400,000)
Provision for deferred tax expense	13,662,000	8,421,000	8,756,000
Net deferred tax expense due to DTA valuation adjustment	7,909,000
Originations of loans held-for-sale	(146,867,000)	(194,901,000)	(190,041,000)
Proceeds from sales of loans held-for-sale	151,289,000	197,654,000	196,431,000
Net gain on sales of mortgage loans	(4,803,000)	(6,343,000)	(5,775,000)
Net discount accretion of purchase accounting adjustment on loans	(1,328,000)	(604,000)
Change in current income taxes receivable	(2,519,000)	260,000	100,000
Increase in cash surrender value of bank-owned life insurance	(1,432,000)	(1,283,000)	(1,277,000)
Death claim on bank owned life insurance			273,000
Change in accrued interest receivable and other assets	(4,492,000)	(53,000)	(4,213,000)
Change in accrued interest payable and other liabilities	1,582,000	967,000	(2,668,000)
Net discount (accretion)/premium amortization on securities	1,881,000	(638,000)	79,000
Securities losses, net	(474,000)	2,213,000	178,000
Amortization of core deposit	96,000	16,000
Amortization of junior subordinated debentures issuance costs	48,000	48,000	47,000
Amortization of senior notes issuance costs	102,000	4,000
Stock based compensation	1,181,000	657,000	613,000
Net gain on sale of other real estate owned	(474,000)	(374,000)	(1,073,000)
Provision for other real estate owned losses	1,708,000	1,570,000	4,076,000
Net loss on disposal of fixed assets	(10,000)	1,000	(20,000)
Loss on transfer of premises to other real estate owned			1,139,000
Net cash provided by (used in) operating activities	37,105,000	27,256,000	21,137,000
Cash flows from investing activities
Proceeds from maturities and calls including pay down of securities available-for-sale	117,389,000	78,305,000	46,230,000
Proceeds from sales of securities available-for-sale	232,462,000	306,400,000	70,176,000
Purchases of securities available-for-sale	(343,470,000)	(210,681,000)	(196,082,000)
Proceeds from maturities and calls including pay down of securities held-to-maturity		3,372,000	13,281,000
Proceeds from sales of Federal Home Loan Bank stock	(2,250,000)	600,000	540,000
Net change in loans	(141,683,000)	(125,540,000)	16,073,000
Improvements in other real estate owned		(16,000)
Proceeds from sales of other real estate owned	6,107,000	7,830,000	18,836,000
Proceeds from disposition of premises and equipment	13,000		30,000
Net purchases of premises and equipment	(1,055,000)	(1,986,000)	(1,280,000)
Cash paid for acquisition, net of cash and cash equivalent retained		(181,357,000)
Net cash (used in) provided by investing activities	(132,487,000)	(123,073,000)	(32,196,000)
Cash flows from financing activities
Net change in deposits	56,140,000	58,805,000	74,031,000
Net change in securities sold under repurchase agreements	4,203,000	(8,355,000)	13,034,000
Net change in other short-term borrowings	45,000,000	55,000,000	(30,000,000)
Payment of senior note issuance costs	(42,000)
Redemption of preferred stock			(47,331,000)
Proceeds from the issuance of senior notes		43,994,000
Repayment of subordinate debt		(45,000,000)
Repayment of note payable		(500,000)
Proceeds from exercise of stock options		11,000
Dividends paid on preferred stock			(2,417,000)
Dividends paid common stock	(1,184,000)	(888,000)
Purchase of treasury stock	(236,000)	(254,000)	(117,000)
Net cash (used in) provided by financing activities	103,881,000	102,813,000	7,200,000
Net change in cash and cash equivalents	8,499,000	6,996,000	(3,859,000)
Cash and cash equivalents at beginning of period	47,334,000	40,338,000	44,197,000
Cash and cash equivalents at end of period	55,833,000	47,334,000	40,338,000
Supplemental cash flow information
Income taxes paid	430,000	211,000	118,000
Interest paid for deposits	5,145,000	4,275,000	3,958,000
Interest paid for borrowings	7,362,000	5,330,000	5,142,000
Non-cash transfer of loans to other real estate owned	3,701,000	1,223,000	8,530,000
Non-cash transfer of premises to other real estate owned	$ 95,000	562,000	468,000
Non-cash transfer of securities available-for-sale to securities held-to-maturity		$ 244,823,000
Change in dividends accrued			$ (544,000)

Consolidated Statements of Chan

Consolidated Statements of Changes in Stockholders' Equity - USD ($) $ in Thousands	Common Stock	Preferred Stock	Additional Paid In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Treasury Stock	Total
Balance at Dec. 31, 2014	$ 34,365	$ 47,331	$ 115,332	$ 100,697	$ (7,713)	$ (95,849)	$ 194,163
Increase (Decrease) in Stockholders' Equity
Net income				15,385			15,385
Other comprehensive income, net of tax					(4,946)		(4,946)
Change in restricted stock	62		(62)
Recapture of restricted stock			35				35
Stock based compensation			613				613
Purchase of treasury stock						(117)	(117)
Redemption of preferred stock		$ (47,331)					(47,331)
Preferred stock accretion and declared dividends				(1,873)			(1,873)
Balance at Dec. 31, 2015	34,427		115,918	114,209	(12,659)	(95,966)	155,929
Increase (Decrease) in Stockholders' Equity
Net income				15,684			15,684
Other comprehensive income, net of tax					3,897		3,897
Dividends declared and paid				(888)			(888)
Change in restricted stock	106		(106)
Tax effect from vesting of restricted stock			174				174
Stock based compensation			657				657
Purchase of treasury stock						(254)	(254)
Redemption of preferred stock	1		10				11
Balance at Dec. 31, 2016	34,534		116,653	129,005	(8,762)	(96,220)	175,210
Increase (Decrease) in Stockholders' Equity
Net income				15,138			15,138
Other comprehensive income, net of tax					10,241		10,241
Dividends declared and paid				(1,184)			(1,184)
Change in restricted stock	92		(92)
Stock based compensation			1,181				1,181
Purchase of treasury stock						(236)	(236)
Balance at Dec. 31, 2017	$ 34,626		$ 117,742	$ 142,959	$ 1,479	$ (96,456)	$ 200,350

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2017
Summary of Significant Accounting Policies
Summary of Significant Accounting Policies	Old Second Bancorp, Inc. and Subsidiaries Notes to Consolidated Financial Statements December 31, 2017, 2016 and 2015 (Table amounts in thousands, except per share data) Note 1: Summary of Significant Accounting Policies The consolidated financial statements of Old Second Bancorp, Inc., and Subsidiaries (the “Company”) include the financial statements of Old Second Bancorp, Inc., a registered bank holding company, and its wholly-owned bank, Old Second National Bank (the “Bank”). The Company uses the accrual basis of accounting for financial reporting purposes. Certain amounts in prior year financial statements have been reclassified to conform to the 2017 presentation. Use of Estimates – The preparation of consolidated financial statements in conformity with generally accepted accounting principles (“GAAP”) and following general practices within the banking industry requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates and assumptions are based on the best available information, actual results could differ from those estimates. Principles of Consolidation – The accompanying consolidated financial statements include the accounts and results of operations of the Company and its subsidiaries after elimination of all significant intercompany accounts and transactions. Assets held in a fiduciary or agency capacity are not assets of the Company or its subsidiaries and are not included in the consolidated financial statements. Segment Reporting – An operating segment is a component of a business entity that engages in business activity from which it may earn revenues and/or incur expenses. It has operating results that are reviewed regularly by the entity’s chief operating decision maker in order to make decisions about resource allocation and performance assessment, and the segment has discrete financial information available for this assessment. As of December 31, 2017, the Company had one operating segment, which is community banking. Therefore, segment reporting is not required. Cash and Cash Equivalents – For purposes of the Consolidated Statements of Cash Flows, management has defined cash and cash equivalents to include cash and due from banks, interest-bearing deposits in other banks, and other short-term investments, such as federal funds sold and securities purchased under agreements to resell. Securities – Securities are classified as available-for-sale or held-to-maturity at the time of purchase or transfer. Securities that are classified as available-for-sale are carried at fair value. Unrealized gains and losses, net of related deferred income taxes, are recorded in stockholders’ equity as a separate component of accumulated other comprehensive income or loss. Unrealized gains and losses are not included in the calculation of regulatory capital. Securities held-to-maturity are carried at amortized cost and the discount or premium created at acquisition or in the transfer from available-for-sale is accreted or amortized to the maturity or expected payoff date but not an earlier call. Discounts are accreted into interest income over the estimated life of the related security and premiums are amortized into income to the earlier of the call date or estimated life of the related security using the level yield method. Purchases and sales of securities are recognized on a trade date basis. Realized securities gains or losses are reported in securities gains (losses), net, in the Consolidated Statements of Income. The cost of securities sold is based on the specific identification method. On a quarterly basis, the Company makes an assessment (at the individual security level) to determine whether there have been any events or circumstances indicating that a security with an unrealized loss is other-than-temporarily impaired (“OTTI”). In evaluating OTTI, the Company considers many factors, including the severity and duration of the impairment; the financial condition and near-term prospects of the issuer, which for debt securities considers external credit ratings and recent downgrades; its ability and intent to hold the security for a period of time sufficient for a recovery in value; and the likelihood that it will be required to sell the security before a recovery in value, which may be at maturity. The amount of the impairment related to other factors is recognized in other comprehensive income (loss) unless management intends to sell the security or believes it is more likely than not that it will be required to sell the security prior to full recovery. Federal Home Loan Bank and Federal Reserve Bank Stock – The Company owns the stock of the Federal Home Loan Bank of Chicago (“FHLBC”) and the Federal Reserve Bank of Chicago (“FRBC”). Both of these entities require the Bank to invest in their nonmarketable stock as a condition of membership. The FHLBC is a governmental sponsored entity. The Bank continues to utilize the various products and services of the FHLBC and management considers this stock to be a long-term investment. FHLBC members are required to own a certain amount of stock based on the level of borrowings and other factors, and may invest in additional amounts. FHLBC stock is carried at cost, classified as a restricted security, and periodically evaluated for impairment based on ultimate recovery of par value. The Company’s ability to redeem the shares owned is dependent on the redemption practices of the FHLBC. The Company records dividends in income on the ex-dividend date. FRBC stock is redeemable at par, and therefore fair value equals cost. Loans Held-for-Sale – The Bank originates residential mortgage loans, which consist of loan products eligible for sale to the secondary market. Residential mortgage loans eligible for sale in the secondary market are carried at fair market value. The fair value of loans held-for-sale is determined using quoted secondary market prices on similar loans. Loans – Loans held-for-investment are carried at the principal amount outstanding, including certain net deferred loan origination fees and costs. Acquired loans were assessed for credit impairment upon acquisition. As no impairment was noted, the loans are carried at the purchased amount, less any purchase accounting discount recorded to mark the loans to fair value. If impairment was noted, the purchase accounting credit mark accretion would be discontinued, and the loan would be evaluated for charge-off to be taken against the remaining mark. Interest income on loans is accrued based on principal amounts outstanding. Loan and lease origination fees, commitment fees, and certain direct loan origination costs are deferred and amortized over the life of the related loans or commitments as a yield adjustment. The acquisition adjustment discount related to purchased loans is accreted into interest income over the contractual life of each loan, or is generally taken into income immediately upon payoff or renewal of the loan. Fees related to standby letters of credit, whose ultimate exercise is remote, are amortized into fee income over the estimated life of the commitment. Other credit-related fees are recognized as fee income when earned. Concentration of Credit Risk – Most of the Company’s business activity is with customers located within Kane, Kendall, DeKalb, DuPage, LaSalle, Will and Cook counties in Illinois. These banking centers surround or are within the Chicago metropolitan area. Therefore, the Company’s exposure to credit risk is significantly affected by changes in the economy in that market area since the Bank generally makes loans within its market. There are no significant concentrations of loans where the customers’ ability to honor loan terms is dependent upon a single economic sector. Commercial Loans – Such credits typically comprise working capital loans, loans for physical asset expansion, asset acquisition loans and other commercial and industrial business loans. Loans to closely held businesses will generally be guaranteed in full or for a meaningful amount by the businesses’ major owners. Commercial loans are made based primarily on the historical and projected cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not behave as forecasted and collateral securing loans may fluctuate in value due to economic or individual performance factors. Minimum standards and underwriting guidelines have been established for all commercial loan types. Lease Financing Receivables – Lease financing receivables are subject to underwriting standards and processes similar to commercial loans. These loans are often secured by equipment or transportation assets, and are made based primarily on the historical and projected cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not behave as forecasted and collateral securing loans may fluctuate in value due to economic or individual performance factors. Real Estate - Commercial Loans – Real estate - commercial loans are subject to underwriting standards and processes similar to commercial and industrial loans. These are loans secured by mortgages on real estate collateral. Commercial real estate loans are viewed primarily as cash flow loans and the repayment of these loans is largely dependent on the successful operation of the property. Loan performance may be adversely affected by factors impacting the general economy or conditions specific to the real estate market such as geographic location and/or property type. Real Estate - Construction Loans – The Company defines real estate - construction loans as loans where the loan proceeds are controlled by the Company and used exclusively for the improvement or development of real estate in which the Company holds a mortgage. Due to the inherent risk in this type of loan, they are subject to other industry specific policy guidelines outlined in the Company’s Credit Risk Policy and are monitored closely. Real Estate - Residential Loans – These are loans that are extended to purchase or refinance 1-4 family residential dwellings, or to purchase or refinance vacant lots intended for the construction of a 1-4 family home. Residential real estate loans are considered homogenous in nature. Homes may be the primary or secondary residence of the borrower or may be investment properties of the borrower. Consumer Loans – Consumer loans include loans extended primarily for consumer and household purposes. These also include overdrafts and other items not captured by the definitions above. Nonaccrual Loans – Generally, commercial and consumer loans, as well as loans secured by real estate are placed on nonaccrual status (i) when either principal or interest payments become 90 days or more past due based on contractual terms unless the loan is sufficiently collateralized such that full repayment of both principal and interest is expected and is in the process of collection within a reasonable period or (ii) when an individual analysis of a borrower’s creditworthiness indicates a credit should be placed on nonaccrual status whether or not the loan is 90 days or more past due. When a loan is placed on nonaccrual status, unpaid interest credited to income is reversed. Generally, after the loan is placed on nonaccrual, all debt service payments are applied to the principal on the loan. Nonaccrual loans are returned to accrual status when the financial position of the borrower and other relevant factors indicate there is no longer doubt that the Company will collect all principal and interest due. Commercial, consumer and real estate loans are generally charged-off when deemed uncollectible. A loss is recorded at that time if the net realizable value can be quantified and it is less than the associated principal outstanding. Troubled Debt Restructurings (“TDRs”) – A restructuring of debt is considered a TDR when (i) the borrower is experiencing financial difficulties and (ii) the creditor grants a concession, such as forgiveness of principal, reduction of the interest rate, changes in payments, or extension of the maturity, that it would not otherwise consider. Loans are not classified as TDRs when the modification is short-term or results in only an insignificant delay or shortfall in the payments to be received. The Company’s TDRs are determined on a case-by-case basis in connection with ongoing loan collection processes. The Company does not accrue interest on any TDRs unless it believes collection of all principal and interest under the modified terms is reasonably assured. For TDRs to accrue interest, the borrower must demonstrate both some level of past performance and the capacity to perform under the modified terms. Generally, six months of consecutive payment performance by the borrower under the restructured terms is required before TDRs are returned to accrual status. However, the period could vary depending on the individual facts and circumstances of the loan. An evaluation of the borrower’s current creditworthiness is used to assess whether the borrower has the capacity to repay the loan under the modified terms. This evaluation includes an estimate of expected cash flows, evidence of strong financial position, and estimates of the value of collateral, if applicable. Impaired Loans – Impaired loans consist of nonaccrual loans and TDRs (both accruing and on nonaccrual). A loan is considered impaired when it is probable that the Company will be unable to collect all contractual principal and interest due according to the terms of the loan agreement based on current information and events. With the exception of TDRs still accruing interest, loans deemed to be impaired are classified as nonaccrual and are exclusive of smaller homogeneous loans, such as home equity, 1-4 family mortgages, and consumer loans. 90-Days or Greater Past Due Loans – 90-days or greater past due loans are loans with principal or interest payments three months or more past due, but that still accrue interest. The Company continues to accrue interest if it determines these loans are sufficiently collateralized and the process of collection will conclude within a reasonable time period. Allowance for Loan and Lease Losses (“ALLL”) – The ALLL is calculated according to GAAP standards and is maintained by management at a level believed adequate to absorb estimated losses inherent in the existing loan portfolio. Determination of the ALLL is inherently subjective since it requires significant estimates and management judgment, and includes a level of imprecision given the difficulty of identifying and assessing the factors impacting loan repayment and estimating the timing and amount of losses. While management utilizes its best judgment and information available, the ultimate adequacy of the ALLL is dependent upon a variety of factors beyond the Company’s direct control, including the performance of the loan portfolio, consideration of current economic trends, changes in interest rates and property values, the amounts and timing of expected future cash flows on impaired loans, estimated losses on pools of homogeneous loans based on an analysis that uses historical loss experience, portfolio growth and concentration risk, management and staffing changes, the interpretation of loan risk classifications by regulatory authorities and other credit market factors. While each component of the ALLL is determined separately, the entire balance is available for the entire loan portfolio. Loans deemed to be uncollectible are charged-off against the ALLL while recoveries of amounts previously charged-off are credited to the ALLL. Approved releases from previously established loan loss reserves authorized under our allowance methodology also reduce the ALLL. Additions to the allowance are established through the provision for loan and lease losses charged to expense. The ALLL methodology consists of (i) specific reserves established for probable losses on individual loans for which the recorded investment in the loan exceeds the present value of expected future cash flows or the net realizable value of the underlying collateral, if collateral dependent, (ii) an allowance based on a historical loss analysis that uses credit loss experience for the prior 20 quarters for each loan category, and (iii) the impact of other internal and external qualitative and credit market factors as assessed by management through detailed loan review, allowance analysis and credit discussions. In 2016, the Company significantly refined its ALLL methodology to further stratify the loan portfolio and apply unique factors to each segment. The changes implemented in 2016 segregate the total loan portfolio into further detail, moving from seven loan classifications to nine when applying management risk factors, and from four loan classifications to nine when applying historical loss rates. The Company also enhanced the prior process of applying management risk factors for changes in loans portfolio trends, such as factors for changes in the trend or volume of past due and classified loans, changes in the nature and volume of the portfolio and concentrations, changes in lending policy, procedures, management and staffing, and other external factors. These factors were historically analyzed in the aggregate to arrive at one risk factor per loan classification; under the revised methodology, the Company assigns each of these components its own risk factor, as well as encompasses an additional risk rating for loans rated as pass/watch. The Company continued to refine its ALLL methodology in 2017, with implementation of additional management factor classifications for newer loan portfolios, such as the Company’s recent purchase of home equity lines of credit (“HELOCs”) and the recently expanded business development company loan portfolio, as these portfolios have not been outstanding long enough to be sufficiently seasoned. In addition, the Company revised the risk weightings for the historical loss factors to reflect a five basis point increase to the loss factor applied in the earliest quarter, and a reduction of five basis points in the most recent quarter, as management believes the lower charge-off levels in the more recent quarters will likely not continue long-term. These modifications to the Company’s ALLL methodology are intended to more accurately reflect all portfolio risk, and resulted in a decrease to the overall unallocated component of the allowance over the past two years. The unallocated component of the allowance was $542,000 as of December 31, 2017, compared to $435,000 as of December 31, 2016 and $2.0 million as of December 31, 2015. All calculations conform to GAAP. Premises and Equipment – Premises, furniture, equipment, and leasehold improvements are stated at cost less accumulated depreciation and amortization. Depreciation expense is determined by the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the shorter of the life of the asset or the lease term including anticipated renewals. Rates of depreciation are generally based on the following useful lives: buildings, 25 to 40 years; building improvements, 3 to 15 years or longer under limited circumstances; and furniture and equipment, 3 to 10 years. Gains and losses on dispositions are included in other noninterest income in the Consolidated Statements of Income. Maintenance and repairs are charged to operating expenses as incurred, while improvements that conform to definitions of tangible property improvements are capitalized and depreciated over the estimated remaining life. Other Real Estate Owned (“OREO”) – Real estate assets acquired in settlement of loans are recorded at the fair value of the property when acquired, less estimated costs to sell, establishing a new cost basis. Physical possession of residential real estate property collateralizing a consumer mortgage loan occurs when legal title is obtained upon foreclosure or when the borrower conveys all interest in the property to satisfy the loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Any deficiency between the net book value and fair value at the foreclosure or deed in lieu date is charged to the ALLL. If fair value subsequently declines, an OREO valuation allowance is established for the decrease between the recorded value and the updated fair value less costs to sell. Such declines are included in other noninterest expense in the Consolidated Statements of Income. A subsequent reversal of an OREO valuation adjustment can occur, but the resultant carrying value cannot exceed the cost basis established at transfer of the loan to OREO. Operating costs after acquisition are also expensed. Mortgage Servicing Rights – The Bank is also involved in the business of servicing mortgage loans. Servicing activities include collecting principal, interest, and escrow payments from borrowers, making tax and insurance payments on behalf of the borrowers, monitoring delinquencies, executing foreclosure proceedings, and accounting for and remitting principal and interest payments to the investors. Mortgage servicing rights represent the right to a stream of cash flows and an obligation to perform specified residential mortgage servicing activities. Mortgage loans that the Company is servicing for others aggregated to $695.1 million and $668.2 million at December 31, 2017, and 2016, respectively. Mortgage loans that the Company is servicing for others are not included in the consolidated balance sheets. Fees received in connection with servicing loans for others are recognized as earned. Loan servicing costs are charged to expense as incurred. Servicing rights are recognized separately as assets when they are acquired through sales of loans and servicing rights are retained. Servicing rights are initially recorded at fair value with the effect recorded in net gains on sales of mortgage loans in the Consolidated Statements of Income. 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. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds and default rates and losses. Servicing fee income, which is included in the Consolidated Statements of Income as mortgage servicing income, is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan and are recorded as income when earned. Under the fair value measurement method, the Company measures mortgage servicing rights at fair value at each reporting date, reports changes in fair value of servicing assets in earnings in the period in which the changes occur, and includes these changes in mortgage servicing rights mark to market in the Consolidated Statements of Income. The fair values of mortgage servicing rights are subject to significant fluctuations as a result of changes in estimated and actual prepayment speeds and default rates and losses. Bank-Owned Life Insurance (“BOLI”) – BOLI represents life insurance policies on the lives of certain Company employees (both current and former) for which the Company is the sole owner and beneficiary. These policies are recorded as an asset on the Consolidated Balance Sheets at their cash surrender value (“CSV”) or the amount that could be realized. The change in CSV and insurance proceeds received are recorded as an increase in cash surrender value of bank-owned life insurance in the Consolidated Statements of Income in noninterest income. Goodwill and Core Deposit Intangible – Goodwill is the excess of an acquisition’s purchase price over the fair value of identified net assets acquired in an acquisition. Goodwill is not deemed to have definitive life span, and therefore is not amortized, but is subject to annual review for impairment. The core deposit intangible (“CDI”) is being amortized on an accelerated method over a ten year estimated useful life. Debt Issuance Costs – Costs associated with the issuance of debt are presented in the Consolidated Balance Sheet as a direct reduction from the carrying value of that debt liability. The deferred issuance costs are amortized over the life the related debt instrument, and included within the debt’s interest expense. Loss Contingencies – Loss contingencies, including claims and legal actions arising in the ordinary course of business, are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. Management does not believe there are such matters that will have a material effect on the financial statements. Wealth Management – Assets held in a fiduciary or agency capacity for customers are not included in the consolidated financial statements as they are not assets of the Company or its subsidiaries. Fee income is included as a component of noninterest income in the Consolidated Statements of Income. Advertising Costs – All advertising costs incurred by the Company are expensed in the period in which they are incurred. Equity Incentive Plan – Compensation cost is recognized for stock options and restricted stock awards issued to employees based upon the fair value of the awards at the date of grant. A binomial model is utilized to estimate the fair value of stock options, which utilizes assumptions for expected volatilities based on the previous five-year historical volatilities of the Company's common stock. Historical data is used to estimate option exercise rates and post-vesting termination behavior, and the risk-free interest rate for the expected term of the option is based on the Treasury yield curve in effect at the time of grant. The market price of the Company’s common stock at the date of grant is used for restricted stock awards, which include restricted stock units. Compensation cost is recognized over the required service period, generally defined as the vesting period. Once the award is settled, the Company would determine whether the cumulative tax deduction exceeded the cumulative compensation cost recognized in the Consolidated Statement of Income. The cumulative tax deduction would include both the deductions from the dividends and the deduction from the exercise or vesting of the award. If the tax benefit received from the cumulative deductions exceeds the tax effect of the recognized cumulative compensation cost, the excess would be recognized as a credit to income tax expense. Income Taxes – The Company files income tax returns in the U.S. federal jurisdiction, and in the states of Illinois, Indiana and Wisconsin. The provision for income taxes is based on income in the consolidated financial statements, rather than amounts reported on the Company’s income tax return. Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities. Any change in tax rates will be recorded in the period in which the law is enacted. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using the enacted tax rates that are expected to apply to taxable income in years in which those temporary differences are expected to be recovered or settled. As of December 31, 2017 and 2016, the Company evaluated tax positions taken for filing with the Internal Revenue Service and all state jurisdictions in which it operates. The Company believes that income tax filing positions will be sustained under examination and does not anticipate any adjustments that would result in a material adverse effect on the Company’s financial condition, results of operations, or cash flows. Accordingly, the Company has not recorded any reserves or related accruals for interest and penalties for uncertain tax positions at December 31, 2017 and 2016. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service from 2014 to 2016, the state of Illinois from 2014 to 2016, and the states of Wisconsin and Indiana from 2009 to 2016. Earnings Per Common Share (“EPS”) – Basic EPS is computed by dividing net income applicable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted EPS is computed by dividing net income applicable to common stockholders by the weighted-average number of common shares outstanding plus the number of additional common shares that would have been outstanding if the dilutive potential shares had been issued. The Company’s potential common shares represent shares issuable under its long-term incentive compensation plans and under the common stock warrant issued to preferred stockholders. Such common stock equivalents are computed based on the treasury stock method using the average market price for the period. Treasury Stock – Treasury stock acquired is recorded at cost and is carried as a reduction of stockholders’ equity in the Consolidated Balance Sheet. Treasury stock issued is valued based on the “last in, first out” inventory method. The difference between the consideration received upon issuance and the carrying value is charged or credited to additional paid-in capital. Mortgage Banking Derivatives – As part of the ongoing residential mortgage business, the Company enters into mortgage banking derivatives such as forward contracts and interest rate lock commitments. The derivatives and loans held-for-sale are carried at fair value with the changes in fair value recorded in current earnings. The net gain or loss on mortgage banking derivatives is included in net gains on sales of loans in the Consolidated Statements of Income . Derivative Financial Instruments – The Company occasionally enters into derivative financial instruments as part of its interest rate risk management strategies. These derivative financial instruments consist primarily of interest rate swaps; in addition, three risk participation agreements were held by the Company as of December 31, 2017, and one was held as of December 31, 2016. All risk participation agreements are recorded at fair value and are immaterial. The Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and whether the Company has elected to designate a derivative as a hedging relationship and apply hedge accounting. A further consideration involves a determination on whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain risks, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. If it is determined that the derivative instrument is not highly effective as a hedge, hedge accounting is discontinued, and the adjustment to fair value of the derivative instrument is recorded in earnings. For a derivative used to hedge changes in cash flows associated with forecasted transactions, the gain or loss on the effective portion of the derivative are deferred and reported as a component of accumulated other comprehensive income, which is a component of stockholders’ equity, until such time the hedged transaction affects earnings. For derivative instrume

Acquisitions

Acquisitions	12 Months Ended
	Dec. 31, 2017
Talmer
Business Acquisition [Line Items]
Acquisitions	Note 2: Acquisitions On December 26, 2017, the Company announced the signing of a definitive agreement and plan of merger (the “Merger Agreement”) to acquire Greater Chicago Financial Corp. and its wholly-owned bank subsidiary, ABC Bank, in an all-cash transaction. Under the terms of the Merger Agreement, the Company will acquire all of the outstanding common stock of Greater Chicago Financial Corp. in a transaction valued at approximately $41.1 million. The Company will acquire and simultaneously retire $6.3 million of outstanding subordinated debentures of Greater Chicago Financial Corp. The ultimate per share consideration for shareholders of Greater Chicago Financial Corp. will depend upon the conversion election of holders of approximately $2.0 million of subordinated debentures that are convertible to common stock. The Merger Agreement requires the purchase price to be increased by an amount equal to the aggregate amount of outstanding principal and accrued but unpaid interest of such converted indebtedness actually converted into Greater Chicago Financial Corp. common stock. ABC Bank had total assets of $342.6 million as of December 31, 2017, including $234.4 million of net loans. The boards of the Company and Greater Chicago Financial Corp. unanimously approved the transaction which is subject to regulatory approval and customary closing conditions. Greater Chicago Financial Corp.’s shareholders have approved the transaction, which is expected to close in the second quarter of 2018. Acquisition costs incurred for the year ending December 31, 2017, related to the pending merger with Greater Chicago Financial Corp. were $65,000, and were expensed as incurred. On October 28, 2016, the Bank completed its previously announced acquisition of the Chicago branch of Talmer Bank and Trust, the banking subsidiary of Talmer Bancorp, Inc. (“Talmer”). As a result of this transaction, the Bank acquired $223.8 million of loans, prior to fair value adjustment, and $48.9 million of deposits. The purchase resulted in the Company establishing a metropolitan Chicago office presence with a strong commercial client focus, and retention of an experienced lending team. The acquisition was funded with security sales and cash on hand, and was recorded applying the acquisition method of accounting. The following table presents the assets acquired and the liabilities assumed, both tangible and intangible, net of fair value adjustments, as of the acquisition date: Talmer Branch Acquisition Summary As of Date of Acquisition 10/28/2016 Assets acquired: Cash on hand $ 122 Loans, net of purchase accounting adjustments 220,988 Premises and equipment, net 230 Goodwill 8,375 Core deposit intangible 659 Other assets acquired, including accrued interest, prepaids 573 Liabilities assumed: Deposits - noninterest bearing demand 28,850 Deposits - interest bearing - Savings, NOW and Money market 17,941 Deposits - Time 2,103 Other liabilities assumed, including escrow deposits and payables 574 Net assets acquired, or total cash paid for acquisition $ Acquisition expenses incurred in 2016 related to the Talmer branch purchase totaled $269,000 as of December 31, 2016; all material acquisition costs identified were paid or accrued as of year end 2016. As of December 31, 2016, the Company recorded $8.5 million of goodwill and acquisition costs that were tax deductible.

Cash and Due from Banks

Cash and Due from Banks	12 Months Ended
	Dec. 31, 2017
Cash and Due from Banks.
Cash and Due from Banks	Note 3: Cash and Due from Banks The Bank is required to maintain reserve balances with the FRBC. In accordance with the FRBC requirements, the average reserve balances were $10.6 million and $10.5 million, for the years December 31, 2017, and 2016, respectively. As of December 31, 2017 and 2016, the required reserve balance was $11.0 million and $11.8 million, respectively. The nature of the Company’s business requires that it maintain amounts with other banks and federal funds which, at times, may exceed federally insured limits. Management monitors these correspondent relationships, and the Company has not experienced any losses in such accounts.

Securities

Securities	12 Months Ended
	Dec. 31, 2017
Securities
Securities	Note 4: Securities Investment Portfolio Management The following table summarizes the amortized cost and fair value of the securities portfolio at December 31, 2017 and December 31, 2016, and the corresponding amounts of gross unrealized gains and losses (in thousands): Gross Gross Amortized Unrealized Unrealized Fair December 31, 2017 Cost Gains Losses Value Securities available-for-sale U.S. Treasuries $ 4,002 $ - $ (55) $ 3,947 U.S. government agencies 13,062 8 (9) 13,061 U.S. government agencies mortgage-backed 12,372 7 (165) 12,214 States and political subdivisions 272,240 7,116 (1,264) 278,092 Corporate bonds 823 21 (11) 833 Collateralized mortgage obligations 66,892 202 (1,155) 65,939 Asset-backed securities 113,983 862 (1,913) 112,932 Collateralized loan obligations 54,271 251 (101) 54,421 Total securities available-for-sale $ 537,645 $ 8,467 $ (4,673) $ 541,439 Gross Gross Amortized Unrealized Unrealized Fair December 31, 2016 Cost Gains Losses Value Securities available-for-sale U.S. government agencies mortgage-backed $ 42,511 $ - $ (977) $ 41,534 States and political subdivisions 68,718 258 (273) 68,703 Corporate bonds 10,957 9 (336) 10,630 Collateralized mortgage obligations 174,352 374 (3,799) 170,927 Asset-backed securities 146,391 341 (8,325) 138,407 Collateralized loan obligations 102,504 29 (896) 101,637 Total securities available-for-sale $ 545,433 $ 1,011 $ (14,606) $ 531,838 During the twelve months ended December 31, 2017, the total securities portfolio increased $9.6 million. Select collateralized mortgage obligations, mortgage-backed securities, corporate bonds and asset-backed securities were liquidated to allow for portfolio repositioning in favor of high quality state and municipal securities. Purchases totaling $270.2 million were executed in this security type during 2017 due to favorable pricing in the rising interest rate environment. These portfolio increases were more than offset by reductions in holdings of asset-backed securities and collateralized mortgage obligations; these reductions were comprised of sales of $146.9 million and paydowns of $13.0 million. Nonmarketable equity investments include FHLBC stock and FRBC stock. FHLBC stock was $5.4 million and $3.1 million at December 31, 2017 and December 31, 2016, respectively. FRBC stock was $4.8 million at December 31, 2017 and December 31, 2016. Our FHLBC stock is necessary to maintain access to FHLBC advances. Securities valued at $301.0 million as of December 31, 2017, an increase from $262.6 million at year-end 2016, were pledged to secure deposits and borrowings, and for other purposes. The fair value, amortized cost and weighted average yield of debt securities at December 31, 2017, by contractual maturity, were as follows in the table below. Securities not due at a single maturity date are shown separately. Weighted Amortized Average Fair Securities available-for-sale Cost Yield Value Due in one year or less $ 6,200 2.41 % $ 6,185 Due after one year through five years 4,346 2.03 4,279 Due after five years through ten years 6,013 3.29 6,234 Due after ten years 273,568 2.95 279,235 290,127 2.93 295,933 Mortgage-backed and collateralized mortgage obligations 79,264 2.94 78,153 Asset-backed securities 113,983 2.56 112,932 Collateralized loan obligations 54,271 4.32 54,421 Total securities available-for-sale $ 537,645 2.99 % $ 541,439 At December 31, 2017, the Company’s investments include asset-backed securities totaling $96.0 million that are backed by student loans originated under the Federal Family Education Loan program (“FFEL”). Under the FFEL, private lenders made federally guaranteed student loans to parents and students. While the program was modified several times before elimination in 2010, FFEL securities are generally guaranteed by the U.S. Department of Education (“DOE”) at not less than 97% of the principal amount of the loans. The guarantee will reduce to 85% if the DOE receives reimbursement requests in excess of 5% of insured loans; reimbursement will drop to 75% if reimbursement requests exceed 9% of insured loans. As of December 31, 2017, the likelihood of the decrease in the government guarantee was minimal as the average rate of reimbursement for 2016 was less than 1.0%. The Company has accumulated the securities of the following three different originators that individually amount to over 10% of the Company’s stockholders equity. The amortized cost and fair value of securities related to these three issuers are as follows: December 31, 2017 Amortized Fair Issuer Cost Value GCO Education Loan Funding Corp $ 27,625 $ 26,588 Towd Point Mortgage Trust 29,312 29,210 Student Loan Marketing Association 25,696 25,917 Securities with unrealized losses at December 31, 2017, and December 31, 2016, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, were as follows (in thousands except for number of securities): Less than 12 months 12 months or more December 31, 2017 in an unrealized loss position in an unrealized loss position Total Number of Unrealized Fair Number of Unrealized Fair Number of Unrealized Fair Securities available-for-sale Securities Losses Value Securities Losses Value Securities Losses Value U.S. Treasuries 1 $ 55 $ 3,947 - $ - $ - 1 $ 55 $ 3,947 U.S. government agencies 2 9 6,550 - - - 2 9 6,550 U.S. government agencies mortgage-backed 4 24 5,501 5 141 4,843 9 165 10,344 States and political subdivisions 13 1,237 45,985 1 27 1,512 14 1,264 47,497 Corporate bonds - - - 1 11 332 1 11 332 Collateralized mortgage obligations 3 31 11,534 8 1,124 40,219 11 1,155 51,753 Asset-backed securities - - - 7 1,913 61,745 7 1,913 61,745 Collateralized loan obligations 3 101 29,313 - - - 3 101 29,313 Total securities available-for-sale 26 $ 1,457 $ 102,830 22 $ 3,216 $ 108,651 48 $ 4,673 $ 211,481 Less than 12 months 12 months or more December 31, 2016 in an unrealized loss position in an unrealized loss position Total Number of Unrealized Fair Number of Unrealized Fair Number of Unrealized Fair Securities available-for-sale Securities Losses Value Securities Losses Value Securities Losses Value U.S. government agencies mortgage-backed 11 $ 957 $ 40,636 1 $ 20 $ 898 12 $ 977 $ 41,534 States and political subdivisions 12 273 35,241 - - - 12 273 35,241 Corporate bonds 1 183 4,817 2 153 5,328 3 336 10,145 Collateralized mortgage obligations 16 3,402 117,752 7 397 18,109 23 3,799 135,861 Asset-backed securities 4 328 17,604 12 7,997 107,112 16 8,325 124,716 Collateralized loan obligations - - - 12 896 81,613 12 896 81,613 Total securities available-for-sale 44 $ 5,143 $ 216,050 34 $ 9,463 $ 213,060 78 $ 14,606 $ 429,110 Recognition of other-than-temporary impairment was not necessary in the year ended December 31, 2017, or the year ended December 31, 2016. The changes in fair value related primarily to interest rate fluctuations. The Company’s review of other-than-temporary impairment confirmed no credit quality deterioration. Years ended December 31, Securities available-for-sale 2017 2016 2015 Proceeds from sales of securities $ 232,462 $ 306,400 $ 70,176 Gross realized gains on securities 2,367 1,675 106 Gross realized losses on securities (1,893) (3,888) (284) Securities realized gains (losses), net $ 474 $ (2,213) $ (178) Income tax expense (benefit) on net realized gains (losses) $ 198 $ (882) $ (71)

Loans

Loans	12 Months Ended
	Dec. 31, 2017
Loans
Loans	Note 5: Loans Major classifications of loans were as follows: December 31, 2017 December 31, 2016 Commercial $ 272,851 $ 228,113 Leases 68,325 55,451 Real estate - commercial 750,991 736,247 Real estate - construction 85,162 64,720 Real estate - residential 426,230 377,851 Consumer 2,774 3,237 Other 1 10,609 11,973 1,616,942 1,477,592 Net deferred loan costs 680 1,217 Total loans $ 1,617,622 $ 1,478,809 1 The “Other” class includes overdrafts. Total loans reflects growth of $138.8 million for the year ended December 31, 2017. There are no significant concentrations of loans where the customers’ ability to honor loan terms is dependent upon a single economic sector although the real estate related categories listed above represent 78.0% and 79.7% of the portfolio at December 31, 2017, and December 31, 2016, respectively. Aged analysis of past due loans by class of loans as of December 31, 2017, and December 31, 2016, were as follows: Recorded Investment 90 days or 90 Days or Greater Past 30-59 Days 60-89 Days Greater Past Total Past Due and December 31, 2017 Past Due Past Due Due Due Current Nonaccrual Total Loans Accruing Commercial $ 995 $ 275 $ - $ 1,270 $ 271,581 $ - $ 272,851 $ - Leases - - - - 68,147 178 68,325 - Real estate - commercial Owner occupied general purpose 1,136 - - 1,136 144,267 455 145,858 - Owner occupied special purpose 226 - - 226 170,546 342 171,114 - Non-owner occupied general purpose - 593 - 593 273,203 1,163 274,959 - Non-owner occupied special purpose - - 248 248 92,923 - 93,171 254 Retail properties - - - - 49,538 1,081 50,619 - Farm - - - - 15,270 - 15,270 - Real estate - construction Homebuilder 129 - - 129 2,221 - 2,350 - Land 1,124 - - 1,124 1,319 - 2,443 - Commercial speculative - - - - 32,028 - 32,028 - All other - - - - 48,140 201 48,341 - Real estate - residential Investor - - - - 55,248 372 55,620 - Multifamily - - - - 125,049 4,723 129,772 - Owner occupied 74 - - 74 123,838 4,674 128,586 - Revolving and junior liens 491 278 - 769 110,291 1,192 112,252 - Consumer - - - - 2,767 7 2,774 - Other 1 37 - - 37 11,252 - 11,289 - Total $ 4,212 $ 1,146 $ 248 $ 5,606 $ 1,597,628 $ 14,388 $ 1,617,622 $ 254 Recorded Investment 90 days or 90 Days or Greater Past 30-59 Days 60-89 Days Greater Past Total Past Due and December 31, 2016 Past Due Past Due Due Due Current Nonaccrual Total Loans Accruing Commercial $ 57 $ 74 $ - $ 131 $ 227,742 $ 240 $ 228,113 $ - Leases - 286 - 286 54,799 366 55,451 - Real estate - commercial Owner occupied general purpose 758 - - 758 135,599 879 137,236 - Owner occupied special purpose - - - - 177,755 385 178,140 - Non-owner occupied general purpose 667 379 - 1,046 229,315 1,930 232,291 - Non-owner occupied special purpose - - - - 118,052 1,013 119,065 - Retail properties - - - - 53,474 1,179 54,653 - Farm 1,353 - - 1,353 13,509 - 14,862 - Real estate - construction Homebuilder - - - - 3,883 - 3,883 - Land - - - - 3,029 - 3,029 - Commercial speculative - - - - 22,654 74 22,728 - All other 364 - - 364 34,509 207 35,080 - Real estate - residential Investor 237 - - 237 54,924 936 56,097 - Multifamily - - - - 96,502 - 96,502 - Owner occupied 274 - - 274 116,900 6,452 123,626 - Revolving and junior liens 225 405 - 630 99,374 1,622 101,626 - Consumer 10 36 - 46 3,191 - 3,237 - Other 1 14 - - 14 13,176 - 13,190 - Total $ 3,959 $ 1,180 $ - $ 5,139 $ 1,458,387 $ 15,283 $ 1,478,809 $ - 1 The “Other” class includes overdrafts and net deferred costs. Credit Quality Indicators: The Company categorizes loans into credit risk categories based on current financial information, overall debt service coverage, comparison against industry averages, historical payment experience, and current economic trends. This analysis includes loans with outstanding balances or commitments greater than $50,000 and excludes homogeneous loans such as home equity lines of credit and residential mortgages. Loans with a classified risk rating are reviewed quarterly regardless of size or loan type. The Company uses the following definitions for classified risk ratings: Special Mention. Loans classified as special mention have a potential weakness that deserves management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects for the loan at some future date. Substandard. Loans classified as substandard are inadequately protected by the current net worth and paying capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that the institution will sustain some loss if the deficiencies are not corrected. Doubtful. Loans classified as doubtful have all the weaknesses inherent in those classified as substandard, with the added characteristic that the weaknesses make collection or liquidation in full, on the basis of currently existing facts, conditions, and values, highly questionable and improbable. Credits that are not covered by the definitions above are pass credits, which are not considered to be adversely rated. Credit Quality Indicators by class of loans as of December 31, 2017, and December 31, 2016, were as follows: December 31, 2017 Special Pass Mention Substandard 1 Doubtful Total Commercial $ 270,889 $ 1,962 $ - $ - $ 272,851 Leases 67,500 - 825 - 68,325 Real estate - commercial Owner occupied general purpose 142,843 1,927 1,088 - 145,858 Owner occupied special purpose 169,621 1,152 341 - 171,114 Non-owner occupied general purpose 271,731 2,065 1,163 - 274,959 Non-owner occupied special purpose 89,582 - 3,589 - 93,171 Retail Properties 48,321 1,217 1,081 - 50,619 Farm 11,755 1,029 2,486 - 15,270 Real estate - construction Homebuilder 2,350 - - - 2,350 Land 2,443 - - - 2,443 Commercial speculative 32,028 - - - 32,028 All other 46,913 1,052 376 - 48,341 Real estate - residential Investor 55,172 - 448 - 55,620 Multifamily 125,049 - 4,723 - 129,772 Owner occupied 122,759 561 5,266 - 128,586 Revolving and junior liens 110,353 - 1,899 - 112,252 Consumer 2,754 - 20 - 2,774 Other 11,289 - - - 11,289 Total $ 1,583,352 $ 10,965 $ 23,305 $ - $ 1,617,622 December 31, 2016 Special Pass Mention Substandard 1 Doubtful Total Commercial $ 214,028 $ 11,558 $ 2,527 $ - $ 228,113 Leases 53,366 976 1,109 - 55,451 Real estate - commercial Owner occupied general purpose 135,503 53 1,680 - 137,236 Owner occupied special purpose 172,353 5,402 385 - 178,140 Non-owner occupied general purpose 229,448 913 1,930 - 232,291 Non-owner occupied special purpose 114,293 - 4,772 - 119,065 Retail Properties 52,207 1,267 1,179 - 54,653 Farm 11,840 1,240 1,782 - 14,862 Real estate - construction Homebuilder 3,883 - - - 3,883 Land 3,029 - - - 3,029 Commercial speculative 22,654 - 74 - 22,728 All other 34,696 - 384 - 35,080 Real estate - residential Investor 55,001 - 1,096 - 56,097 Multifamily 96,502 - - - 96,502 Owner occupied 115,831 570 7,225 - 123,626 Revolving and junior liens 99,286 - 2,340 - 101,626 Consumer 3,236 - 1 - 3,237 Other 13,165 25 - - 13,190 Total $ 1,430,321 $ 22,004 $ 26,484 $ - $ 1,478,809 1 The substandard credit quality indicator includes both potential problem loans that are currently performing and nonperforming loans. The Company had $1.3 million and $1.8 million in consumer mortgage loans in the process of foreclosure as of December 31, 2017 and December 31, 2016, respectively. Impaired loans, which include nonaccrual loans and troubled debt restructurings, by class of loan as of December 31 were as follows: December 31, 2017 December 31, 2016 Unpaid Unpaid Recorded Principal Related Recorded Principal Related Investment Balance Allowance Investment Balance Allowance With no related allowance recorded Commercial $ - $ - $ - $ 240 $ 388 $ - Leases 178 213 - 366 371 - Commercial real estate Owner occupied general purpose 455 495 - 1,881 2,131 - Owner occupied special purpose 342 498 - 385 518 - Non-owner occupied general purpose 1,163 1,538 - 1,744 2,010 - Non-owner occupied special purpose - - - 1,013 1,649 - Retail properties 1,081 1,177 - 1,179 1,235 - Farm - - - - - - Construction Homebuilder - - - - - - Land - - - - - - Commercial speculative - - - 74 81 - All other 201 229 - 207 221 - Residential Investor 372 676 - 1,841 2,308 - Multifamily 4,723 4,965 - - - - Owner occupied 5,208 6,680 - 9,824 11,391 - Revolving and junior liens 1,125 1,313 - 2,484 3,018 - Consumer 7 8 - - - - Total impaired loans with no recorded allowance 14,855 17,792 - 21,238 25,321 - With an allowance recorded Commercial - - - - - - Leases - - - - - - Commercial real estate Owner occupied general purpose - - - - - - Owner occupied special purpose - - - - - - Non-owner occupied general purpose - - - 246 595 246 Non-owner occupied special purpose - - - - - - Retail properties - - - - - - Farm - - - - - - Construction Homebuilder - - - - - - Land - - - - - - Commercial speculative - - - - - - All other - - - - - - Residential Investor 829 829 10 - - - Multifamily - - - - - - Owner occupied 3,443 3,443 43 803 853 803 Revolving and junior liens 985 985 91 - - - Consumer - - - - - - Total impaired loans with a recorded allowance 5,257 5,257 144 1,049 1,448 1,049 Total impaired loans $ 20,112 $ 23,049 $ 144 $ 22,287 $ 26,769 $ 1,049 Average recorded investment and interest income recognized on impaired loans by class of loan for the years ending December 31 were as follows: Year to date Year to date Year to date December 31, 2017 December 31, 2016 December 31, 2015 Average Interest Average Interest Average Interest Recorded Income Recorded Income Recorded Income Investment Recognized Investment Recognized Investment Recognized With no related allowance recorded Commercial $ 120 $ - $ 155 $ - $ 785 $ - Lease 272 - 183 - - - Commercial real estate Owner occupied general purpose 1,168 - 2,098 87 4,720 82 Owner occupied special purpose 364 - 574 - 1,280 - Non-owner occupied general purpose 1,453 - 1,395 2 2,939 3 Non-owner occupied special purpose 507 - 507 - 712 - Retail properties 1,130 - 589 - - - Farm - - 636 - 636 - Construction Homebuilder - - - - 895 - Land - - - - - - Commercial speculative 37 - 79 - 42 - All other 204 - 103 - 145 - Residential Investor 1,106 - 1,874 47 2,251 51 Multifamily 2,362 - - - - - Owner occupied 7,516 44 10,181 158 10,979 160 Revolving and junior liens 1,804 1 2,608 29 2,484 7 Consumer 4 - - - - - Total impaired loans with no recorded allowance 18,047 45 20,982 323 27,868 303 With an allowance recorded Commercial - - 2 - 2 - Leases - - - - - - Commercial real estate Owner occupied general purpose - - - - - - Owner occupied special purpose - - - - - - Non-owner occupied general purpose 123 - 123 - 38 - Non-owner occupied special purpose - - - - - - Retail properties - - - - - - Farm - - - - - - Construction Homebuilder - - - - - - Land - - - - - - Commercial speculative - - - - - - All other - - - - 135 - Residential Investor 414 43 - - 67 - Multifamily - - - - - - Owner occupied 2,123 123 457 - 68 - Revolving and junior liens 493 35 23 - 208 3 Consumer - - - - - - Total impaired loans with a recorded allowance 3,153 201 605 - 518 3 Total impaired loans $ 21,200 $ 246 $ 21,587 $ 323 $ 28,386 $ 306 Troubled debt restructurings (“TDRs”) are loans for which the contractual terms have been modified and both of these conditions exist: (1) there is a concession to the borrower and (2) the borrower is experiencing financial difficulties. Loans are restructured on a case-by-case basis during the loan collection process with modifications generally initiated at the request of the borrower. These modifications may include reduction in interest rates, extension of term, deferrals of principal, and other modifications. The Bank participates in the U.S. Department of the Treasury’s (the “Treasury”) Home Affordable Modification Program (“HAMP”) which gives qualifying homeowners an opportunity to refinance into more affordable monthly payments. The specific allocation of the ALLL on a TDR is determined by either discounting the modified cash flows at the original effective rate of the loan before modification or is based on the underlying collateral value less costs to sell, if repayment of the loan is collateral-dependent. If the resulting amount is less than the recorded book value, the Bank either establishes a valuation allowance (i.e. specific reserve) as a component of the ALLL or charges off the impaired balance if it determines that such amount is a confirmed loss. This method is used consistently for all segments of the portfolio. Loans that were modified during the period are summarized as follows: TDR Modifications Twelve months ended December 31, 2017 # of Pre-modification Post-modification contracts recorded investment recorded investment Troubled debt restructurings Real estate - commercial Other 1 1 $ 97 $ 131 Real estate - residential Owner occupied HAMP 2 2 184 189 Other 1 1 41 42 Revolving and junior liens HAMP 2 1 49 49 Other 1 6 319 350 Total 11 $ 690 $ 761 TDR Modifications Twelve months ended December 31, 2016 # of Pre-modification Post-modification contracts recorded investment recorded investment Troubled debt restructurings Real estate - commercial Other 1 2 $ 312 $ 205 Real estate - residential Owner occupied HAMP 2 2 419 262 Revolving and junior liens HAMP 2 3 252 228 Other 1 3 808 777 Total 10 $ 1,791 $ 1,472 1 Other: Change of terms from bankruptcy court 2 HAMP: Home Affordable Modification Program TDRs are classified as being in default on a case-by-case basis when they fail to be in compliance with the modified terms. There were no TDRs that defaulted during year 2017 and 2016. The Bank had no commitments to borrowers whose loans were classified as impaired at December 31, 2017. Loans to principal officers, directors, and their affiliates, which are made in the ordinary course of business, were as follows at December 31: 2017 2016 Beginning balance $ 1,703 $ 1,787 New loans 20 157 Repayments and other reductions (199) (241) Change in related party status - - Ending balance $ 1,524 $ 1,703 No loans to principal officers, directors, and their affiliates were past due greater than 90 days at either December 31, 2017, or December 31, 2016.

Allowance for Loan Losses

Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2017
Allowance for Loan Losses
Allowance for Loan Losses	Note 6: Allowance for Loan and Lease losses Changes in the ALLL by segment of loans based on method of impairment for the year ended December 31, 2017, were as follows: Real Estate Real Estate Real Estate Allowance for loan and lease losses: Commercial Leases Commercial Construction Residential Consumer Other Total Beginning balance $ 1,629 $ 633 $ 9,547 $ 389 $ 2,692 $ 833 $ 435 $ 16,158 Charge-offs 25 215 309 23 1,347 386 1 2,306 Recoveries 30 - 161 377 980 243 18 1,809 Provision (Release) 819 274 123 180 (520) 834 90 1,800 Ending balance $ 2,453 $ 692 $ 9,522 $ 923 $ 1,805 $ 1,524 $ 542 $ 17,461 Ending balance: Individually evaluated for impairment $ - $ - $ - $ - $ 53 $ 91 $ - $ 144 Ending balance: Collectively evaluated for impairment $ 2,453 $ 692 $ 9,522 $ 923 $ 1,752 $ 1,433 $ 542 $ 17,317 Loans: Ending balance $ 272,851 $ 68,325 $ 750,991 $ 85,162 $ 426,230 $ 2,774 $ 11,289 $ 1,617,622 Ending balance: Individually evaluated for impairment $ - $ 178 $ 3,041 $ 201 $ 14,575 $ 2,117 $ - $ 20,112 Ending balance: Collectively evaluated for impairment $ 272,851 $ 68,147 $ 747,950 $ 84,961 $ 411,655 $ 657 $ 11,289 $ 1,597,510 Changes in the ALLL by segment of loans based on method of impairment for December 31, 2016, were as follows: Real Estate Real Estate Real Estate Allowance for loan and lease losses: Commercial Leases Commercial Construction Residential Consumer Other Total Beginning balance $ 1,463 $ 633 $ 9,013 $ 265 $ 1,694 $ 1,190 $ 1,965 $ 16,223 Charge-offs 95 23 1,633 23 1,072 344 - 3,190 Recoveries 32 5 640 96 1,331 253 18 2,375 Provision (Release) 229 18 1,527 51 739 (266) (1,548) 750 Ending balance $ 1,629 $ 633 $ 9,547 $ 389 $ 2,692 $ 833 $ 435 $ 16,158 Ending balance: Individually evaluated for impairment $ - $ - $ 246 $ - $ 803 $ - $ - $ 1,049 Ending balance: Collectively evaluated for impairment $ 1,629 $ 633 $ 9,301 $ 389 $ 1,889 $ 833 $ 435 $ 15,109 Loans: Ending balance $ 228,113 $ 55,451 $ 736,247 $ 64,720 $ 377,851 $ 3,237 $ 13,190 $ 1,478,809 Ending balance: Individually evaluated for impairment $ 240 $ 366 $ 6,448 $ 281 $ 14,952 $ - $ - $ 22,287 Ending balance: Collectively evaluated for impairment $ 227,873 $ 55,085 $ 729,799 $ 64,439 $ 362,899 $ 3,237 $ 13,190 $ 1,456,522 Changes in the ALLL by segment of loans based on method of impairment for the year ended December 31, 2015, were as follows: Commercial Real Estate Real Estate Real Estate Allowance for loan and lease losses: & Leases Commercial Construction Residential Consumer Other Total Beginning balance $ 1,644 $ 12,577 $ 1,475 $ 1,981 $ 1,454 $ 2,506 $ 21,637 Charge-offs 993 1,653 2 1,639 483 - 4,770 Recoveries 451 1,595 276 1,075 359 - 3,756 Provision (Release) 994 (3,506) (1,484) 277 (140) (541) (4,400) Ending balance $ 2,096 $ 9,013 $ 265 $ 1,694 $ 1,190 $ 1,965 $ 16,223 Ending balance: Individually evaluated for impairment $ 3 $ - $ - $ 31 $ - $ - $ 34 Ending balance: Collectively evaluated for impairment $ 2,093 $ 9,013 $ 265 $ 1,663 $ 1,190 $ 1,965 $ 16,189 Loans: Ending balance $ 141,315 $ 605,721 $ 19,806 $ 351,007 $ 4,216 $ 11,650 $ 1,133,715 Ending balance: Individually evaluated for impairment $ 73 $ 5,396 $ 83 $ 15,334 $ - $ - $ 20,886 Ending balance: Collectively evaluated for impairment $ 141,242 $ 600,325 $ 19,723 $ 335,673 $ 4,216 $ 11,650 $ 1,112,829 The Company’s allowance for loan and lease loss is calculated in accordance with GAAP and relevant supervisory guidance. All management estimates were made in light of observable trends within loan portfolio segments, market conditions and established credit review administration practices.

Other Real Estate Owned

Other Real Estate Owned	12 Months Ended
	Dec. 31, 2017
Other Real Estate Owned
Other Real Estate Owned	Note 7: Other Real Estate Owned Details related to the activity in the other real estate owned (“OREO”) portfolio, net of valuation reserve, for the periods presented are itemized in the following table. Twelve Months Ended December 31, Other real estate owned 2017 2016 2015 Balance at beginning of period $ 11,916 $ 19,141 $ 31,982 Property additions 3,796 1,785 8,998 Property improvements - 16 - Less: Proceeds from property disposals, net of participation purchase and of gains/losses 5,633 7,456 17,763 Period valuation adjustments 1,708 1,570 4,076 Balance at end of period $ 8,371 $ 11,916 $ 19,141 Activity in the valuation allowance was as follows: Twelve Months Ended December 31, 2017 2016 2015 Balance at beginning of period $ 9,982 $ 14,127 $ 19,229 Provision for unrealized losses 1,708 1,570 4,076 Reductions taken on sales (3,482) (5,867) (9,271) Other adjustments - 152 93 Balance at end of period $ 8,208 $ 9,982 $ 14,127 Expenses related to OREO, net of lease revenue includes: Twelve Months Ended December 31, 2017 2016 2015 Gain on sales, net $ (474) $ (374) $ (1,073) Provision for unrealized losses 1,708 1,570 4,076 Operating expenses 1,227 1,765 2,888 Less: Lease revenue 296 218 700 Net OREO expense $ 2,165 $ 2,743 $ 5,191

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2017
Premises and Equipment
Premises and Equipment	Note 8: Premises and Equipment Premises and equipment at December 31 were as follows: 2017 2016 Accumulated Accumulated Depreciation/ Net Book Depreciation/ Net Book Cost Amortization Value Cost Amortization Value Land $ 16,124 $ - $ 16,124 $ 16,141 $ - $ 16,141 Buildings 41,499 22,935 18,564 41,409 21,966 19,443 Leasehold improvements 156 144 12 156 86 70 Furniture and equipment 42,910 39,982 2,928 42,875 39,552 3,323 Total Premises and Equipment $ 100,689 $ 63,061 $ 37,628 $ 100,581 $ 61,604 $ 38,977

Deposits

Deposits	12 Months Ended
	Dec. 31, 2017
Deposits
Deposits	Note 9: Deposits Major classifications of deposits at December 31 were as follows: 2017 2016 Noninterest bearing demand $ 572,404 $ 513,688 Savings 262,220 256,159 NOW accounts 429,448 419,417 Money market accounts 276,082 275,273 Certificates of deposit of less than $100,000 216,493 228,993 Certificates of deposit of $100,000 through $250,000 122,489 110,992 Certificates of deposit of more than $250,000 43,789 62,263 Total deposits $ 1,922,925 $ 1,866,785 Growth in total deposits stemmed from the late 2016 Talmer branch acquisition; the Company assumed $48.9 million of additional deposits, primarily noninterest bearing demand accounts. The Company had $18.8 million in brokered certificates of deposit as of December 31, 2017. The Company had $5.9 million in brokered certificates of deposit as of December 31, 2016. Deposits held by senior officers and directors, including their related interests, totaled $2.6 million and $1.6 million as of December 31, 2017 and 2016. At December 31, 2017, scheduled maturities of time deposits were as follows: 2018 $ 158,547 2019 101,609 2020 84,951 2021 32,271 2022 5,393 Total time deposits $ 382,771

Borrowings

Borrowings	12 Months Ended
	Dec. 31, 2017
Borrowings
Borrowings	Note 10: Borrowings The following table is a summary of borrowings as of December 31, 2017, and December 31, 2016. Junior subordinated debentures are discussed in detail in Note 11: 2017 2016 Securities sold under repurchase agreements $ 29,918 $ 25,715 FHLBC advances 1 115,000 70,000 Junior subordinated debentures 57,639 57,591 Senior notes 44,058 43,998 Total borrowings $ 246,615 $ 197,304 1 Included in other short-term borrowing on the balance sheet. The Company enters into deposit sweep transactions where the transaction amounts are secured by pledged securities. These transactions consistently mature within 1 to 90 days from the transaction date and are governed by sweep repurchase agreements. All sweep repurchase agreements are treated as financings secured by U.S. government agencies and collateralized mortgage-backed securities and had a carrying amount of $29.9 million at December 31, 2017, and $25.7 million at December 31, 2016. The fair value of the pledged collateral was $40.0 million and $43.0 million at December 31, 2017 and December 31, 2016, respectively. At December 31, 2017, there were no customers with secured balances exceeding 10% of stockholders’ equity. Total FHLBC advances are generally limited to the lower of 35% of total assets and the amount of acceptable collateral adjusted for applicable funding percentages as determined by the FHLBC. As of December 31, 2017, the Bank had outstanding advances in the amount of $115.0 million with $110.0 million at an interest rate of 1.42% and $5.0 million at an interest rate at 1.44%. As of December 31, 2016, the Bank had outstanding advances in the amount of $70.0 million at an interest rate of 0.70%. As of December 31, 2017, FHLBC stock owned by the Bank was valued at $5.4 million, the fair value of securities pledged to the FHLBC was $80.9 million, and the principal balance of loans pledged was $277.4 million. Based on the total amount of securities and loans pledged, the Bank had total borrowing capacity of $286.3 million. Adjusting for the outstanding advances and letters of credit, the Bank had a remaining funding availability of $132.0 million on December 31, 2017. The Company completed a debt retirement and simultaneous senior debt offering in the fourth quarter of 2016. Subordinated debt of $45.0 million and $500,000 of senior debt outstanding, scheduled to mature in March 2018, were paid off with the proceeds of a $45.0 million senior notes issuance and cash on hand. The senior notes mature in ten years, and terms include interest payable semiannually at 5.75% for five years. Beginning December 2021, the senior debt will pay interest at a floating rate, with interest payable quarterly at three month LIBOR plus 385 basis points. The notes are redeemable, in whole or in part, at the option of the Company, beginning with the interest payment date on December 31, 2021, and on any floating rate interest payment date thereafter, at a redemption price equal to 100% of the principal amount of the notes plus accrued and unpaid interest. As of December 31, 2017 and 2016, unamortized debt issuance costs related to the senior notes were $942,000 and $1.0 million, respectively, and are included as a reduction of the balance of the senior notes on the Consolidated Balance Sheet. These deferred issuance costs will be amortized to interest expense over the ten year term of the notes and included in the Consolidated Statements of Income. Scheduled maturities and weighted average rates of borrowings for the years ended December 31 were as follows: 2017 2016 Weighted Weighted Average Average Balance Rate Balance Rate 2017 N/A N/A $ 95,715 0.51 % 2018 $ 144,918 0.86 % - - 2019 - - - - 2020 - - - - 2021 - - - - 2022 - - - - Thereafter 101,697 6.01 101,589 6.65 Total borrowings $ 246,615 2.98 % $ 197,304 3.67 %

Junior Subordinated Debentures

Junior Subordinated Debentures	12 Months Ended
	Dec. 31, 2017
Junior Subordinated Debentures.
Junior Subordinated Debentures	Note 11: Junior Subordinated Debentures The Company completed the sale of $27.5 million of cumulative trust preferred securities by its unconsolidated subsidiary, Old Second Capital Trust I in June 2003. An additional $4.1 million of cumulative trust preferred securities were sold in July 2003. The costs associated with the issuance of the cumulative trust preferred securities are being amortized over 30 years. The trust preferred securities may remain outstanding for a 30‑year term but, subject to regulatory approval, can be called in whole or in part by the Company after June 30, 2008, and can be exercised by the Company from time to time thereafter. When not in deferral, distributions on the securities are payable quarterly at an annual rate of 7.80%. The Company issued a new $32.6 million subordinated debenture to Old Second Capital Trust I in return for the aggregate net proceeds of this trust preferred offering. The interest rate and payment frequency on the debenture are equivalent to the cash distribution basis on the trust preferred securities. The Company sold an additional $25.0 million of cumulative trust preferred securities through a private placement completed by an additional, unconsolidated subsidiary, Old Second Capital Trust II, in April 2007. These trust preferred securities also mature in 30 years, but subject to the aforementioned regulatory approval, can be called in whole or in part on a quarterly basis commencing June 15, 2017. The quarterly cash distributions on the securities are fixed at 6.77% through June 15, 2017, and float at 150 basis points over three-month LIBOR thereafter. The Trust II issuance converted from fixed to float rate at three month LIBOR plus 150 basis points on June 16, 2017; as of December 31, 2017, the rate effective for the Trust II issuance was 3.09%. Upon conversion to a floating rate, a cash flow hedge was initiated which resulted in the total interest rate period on the debt of 4.30% as of December 31, 2017, compared to the rate paid prior to June 15, 2017 of 6.77%. The Company issued a new $25.8 million subordinated debenture to the Old Second Capital Trust II in return for the aggregate net proceeds of this trust preferred offering. The interest rate and payment frequency on the debenture are equivalent to the cash distribution basis on the trust preferred securities. Both of the debentures issued by the Company are disclosed on the Consolidated Balance Sheet as junior subordinated debentures and the related interest expense for each issuance is included in the Consolidated Statements of Income. As of December 31, 2017, and 2016, unamortized debt issuance costs related to the junior subordinated debentures were $739,000 and $787,000 respectively, and are included as a reduction to the balance of the junior subordinated debentures on the Consolidated Balance Sheet. Under the terms of the subordinated debentures issued to each of Old Second Capital Trust I and II, the Company is allowed to defer payments of interest for 20 quarterly periods without default or penalty, but such amounts continue to accrue. Also during a deferral period, the Company generally may not pay cash dividends on or repurchase its common stock or preferred stock. As of December 31, 2017, the Company is current on the payments due on these securities.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2017
Income Taxes
Income Taxes	Note 12: Income Taxes Income tax expense for years ending December 31 were as follows: 2017 2016 2015 Current federal $ (2,407) $ 399 $ 220 Deferred federal 11,724 6,824 7,023 Deferred state 372 1,597 1,733 Expense due to enactment of federal tax reform 9,475 - - Total income tax expenses $ 19,164 $ 8,820 $ 8,976 The following were the components of the deferred tax assets and liabilities as of December 31: 2017 2016 Allowance for loan and lease losses $ 5,377 $ 7,057 Deferred compensation 650 735 Amortization of core deposit intangible 827 1,401 Goodwill amortization/impairment 6,087 10,127 Stock based compensation 866 946 OREO write-downs 2,385 5,110 Federal net operating loss (“NOL”) carryforward 7,240 19,362 State net operating loss (“NOL”) carryforward 7,020 7,735 Deferred tax credit - 2,058 Other assets 1,017 1,199 Total deferred tax assets 31,469 55,730 Accumulated depreciation on premises and equipment (384) (681) Mortgage servicing rights (2,086) (2,760) State tax benefits (2,389) (4,127) Other liabilities (545) (526) Total deferred tax liabilities (5,404) (8,094) Net deferred tax asset before adjustments related to other comprehensive loss 26,065 47,636 Tax effect of adjustments related to other comprehensive loss (709) 5,828 Net deferred tax asset $ 25,356 $ 53,464 On December 22, 2017, H.R.1, commonly known as the Tax Cuts and Jobs Act (the “Act”), was signed into law. Among other things, the Act reduces the corporate federal tax rate from 35% to 21% effective January 1, 2018. As a result the Company is required to remeasure, through income tax expense, deferred tax assets and liabilities using the enacted rate at which these items are expected to recover or settle. The re-measurement of the Company’s net deferred tax asset resulted in additional income tax expense of approximately $9.5 million. The Company also re-measured the net deferred tax asset as a result of the Illinois income tax increase effective as of July 1, 2017, resulting in a benefit of approximately $1.6 million. At December 31, 2017, the Company had a $34.5 million federal net operating loss carryforward of which, $10.6 million expires in 2031, $8.6 million expires in 2032, and $15.3 million expires in 2033. The Company had a $74.1 million state net operating loss carryforward of which $73.6 million expires in 2025, and the rest expires starting in 2026. In addition, the Company had a $2.6 million alternative minimum tax credit carryforwards which do not expire and are now carried as tax receivables since, under the new federal law, the Company expects to recover the entire amount by 2022 via refund. The components of the provision for deferred income tax expense for the years ending December 31 were as follows: 2017 2016 2015 Provision for loan and lease losses $ 1,680 $ 42 $ 2,480 Deferred Compensation 85 (45) 97 Amortization of core deposit intangible 574 228 230 Stock based compensation 80 (132) (151) OREO write-downs 2,725 1,807 1,722 Federal net operating loss carryforward 12,122 4,743 2,896 State net operating loss carryforward 715 1,011 659 Deferred tax credit 2,058 (309) (198) Depreciation (297) 80 (201) Mortgage servicing rights (674) 276 164 Goodwill amortization/impairment 4,040 1,496 1,506 State tax benefits (1,738) (559) (604) Other, net 201 (217) 156 Total deferred tax expense $ 21,571 $ 8,421 $ 8,756 Effective tax rates differ from federal statutory rates applied to financial statement income for the years ended December 31 due to the following: 2017 2016 2015 Tax at statutory federal income tax rate $ 11,817 $ 8,577 $ 8,526 Nontaxable interest income, net of disallowed interest deduction (1,976) (347) (253) BOLI income (501) (449) (487) State income taxes, net of federal benefit 1,775 1,148 1,126 Impact of Federal tax rate change 9,475 - - Impact of Illinois tax rate change (1,566) - - Other, net 140 (109) 64 Total tax at effective tax rate $ 19,164 $ 8,820 $ 8,976 The Company evaluated positive and negative evidence in order to determine if it was more likely than not that the deferred tax asset would be recovered through future income. Significant positive evidence evaluated included recent and projected earnings, significantly improved asset quality and an improved capital position. No negative evidence was noted.

Equity Compensation Plans

Equity Compensation Plans	12 Months Ended
	Dec. 31, 2017
Equity Compensation Plans
Equity Compensation Plans	Note 13: Equity Compensation Plans The Company’s 2008 Equity Incentive Plan was in effect for years prior to 2014, and authorized the issuance of the Company’s common stock, which included share grants in the form of qualified stock options, non-qualified stock options, restricted stock, restricted stock units and stock appreciation rights. Under the 2008 Equity Incentive Plan, stock based awards were eligible to be granted to selected directors, officers or employees at the discretion of the Board of Directors. All stock options granted under the 2008 Incentive Plan have vested; however, all such options issued prior to 2009 have expired as of December 31, 2017. The Company granted 16,500 stock options in 2009 under the 2008 Equity Incentive Plan, 9,000 of which are vested and outstanding as of December 31, 2017. The stock option awards had a vesting period of three years, and a term of ten years. No other stock options were granted in 2009 through 2017 period. There were no stock option shares exercised during the years ending December 31, 2017 and 2015, and 1,500 stock options were exercised during the year ending December 31, 2016. At December 31, 2017, there is no unrecognized compensation cost related to unvested stock options as all stock options of the Company’s common stock have fully vested. A summary of stock option activity in the Plans for the year ending December 31, 2017, is as follows (in dollars): Weighted- Weighted Average Average Remaining Exercise Contractual Aggregate Shares Price Term (years) Intrinsic Value Beginning outstanding 94,500 $ 25.82 - - Canceled (44,500) 27.75 - - Expired (41,000) 27.75 - - Ending outstanding 9,000 $ 7.49 1.1 $ 55,440 Exercisable at end of period 9,000 $ 7.49 1.1 $ 55,440 A summary of stock option activity as of each year is as follows (in dollars): 2017 2016 2015 Intrinsic value of options exercised $ - $ 2,790 $ - Cash received from option exercises - 11,235 - Tax benefit realized from option exercises - 91 - Weighted average fair value of options granted - - - There are stock-based awards outstanding under the Company’s 2008 Equity Incentive Plan (the “2008 Plan”) and the Company’s 2014 Equity Incentive Plan (the “2014 Plan,” and together with the 2008 Plan, the “Plans”). The 2014 Plan was approved at the 2014 annual meeting of stockholders; a maximum of 375,000 shares were authorized to be issued under this plan. Following approval of the 2014 Plan, no further awards will be granted under the 2008 Plan or any other Company equity compensation plan. At the May 2016 annual stockholders meeting, an amendment to the 2014 Plan authorized an additional 600,000 shares to be issued, which resulted in a total of 975,000 shares authorized for issuance under this plan. The Plan authorizes the granting of qualified stock options, non-qualified stock options, restricted stock, restricted stock units, and stock appreciation rights. Awards may be granted to selected directors and officers or employees under the 2014 Plan at the discretion of the Compensation Committee of the Company’s Board of Directors. As of December 31, 2017, 453,209 shares remained available for issuance under the 2014 Plan. Total compensation cost that has been charged for the 2014 Plan was $1.2 million, $657,000 and $613,000 for the years ending December 31, 2017, 2016 and 2015, respectively. Under the 2014 Plan, upon a change in control of the Company, if (i) the 2014 Plan is not an obligation of the successor entity following the change in control, or (ii) the 2014 Plan is an obligation of the successor entity following the change in control and the participant incurs an involuntary termination, then the stock options, stock appreciation rights, stock awards and cash incentive awards under the 2014 Plan will become fully exercisable and vested. Performance-based awards generally will vest based upon the level of achievement of the applicable performance measures through the change in control. Restricted stock awards under the 2014 Plan generally entitle holders to voting and dividend rights upon grant and are subject to forfeiture until certain restrictions have lapsed including employment for a specific period. Restricted stock units under the Plans are also subject to forfeiture until certain restrictions have lapsed including employment for a specific period but do not entitle holders to voting rights until the restricted period ends and shares are transferred in connection with the units. There were 161,500 restricted awards issued during the year ending December 31, 2017. There were 170,000 restricted awards issued during the year ending December 31, 2016. Compensation expense is recognized over the vesting period of the restricted award based on the market value of the award on the issue date. A summary of changes in the Company’s unvested restricted awards for the year ending December 31, 2017, is as follows: December 31, 2017 Weighted Restricted Average Stock Shares Grant Date and Units Fair Value Unvested at January 1 409,000 $ 5.89 Granted 161,500 11.04 Vested (91,500) 5.07 Forfeited (14,000) 7.53 Unvested at December 31 465,000 $ 7.79 Total unrecognized compensation cost of restricted awards was $1.7 million as of December 31, 2017, which is expected to be recognized over a weighted-average period of 2.17 years.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2017
Earnings Per Share
Earnings Per Share	Note 14: Earnings Per Share The earnings per share, both basic and diluted, are included below as of December 31 (in thousands except for share data): 2017 2016 2015 Basic earnings per share: Weighted-average common shares outstanding 29,600,702 29,532,510 29,476,821 Net income $ 15,138 $ 15,684 $ 15,385 Preferred stock dividends and accretion - - 1,873 Net income available to common stockholders $ 15,138 $ 15,684 $ 13,512 Basic earnings per share $ 0.51 $ 0.53 $ 0.46 Diluted earnings per share: Weighted-average common shares outstanding 29,600,702 29,532,510 29,476,821 Dilutive effect of unvested restricted awards1 435,142 305,678 253,253 Dilutive effect of stock options 2,573 743 - Diluted average common shares outstanding 30,038,417 29,838,931 29,730,074 Net Income $ 15,138 $ 15,684 $ 13,512 Diluted earnings per share $ 0.50 $ 0.53 $ 0.46 Number of antidilutive options and warrants excluded from the diluted earnings per share calculation 815,339 900,839 977,839 1 Includes the common stock equivalents for restricted share awards that are dilutive . The above earnings per share calculation did not include a warrant for 815,339 shares of common stock that was outstanding as of December 31, 2017, 2016 and 2015, because the warrant was anti-dilutive at an exercise price of $13.43. Of note, the warrant was sold at auction by the Treasury in June 2013 to a third party investor.

Commitments

Commitments	12 Months Ended
	Dec. 31, 2017
Commitments
Commitments	Note 15: Commitments In the normal course of business, there are outstanding commitments that are not reflected in the Consolidated Financial Statements. Commitments include financial instruments that involve, to varying degrees, elements of credit, interest rate, and liquidity risk. In management’s opinion, these do not represent unusual risks and management does not anticipate significant losses as a result of these transactions. The Company uses the same credit policies in making commitments and conditional obligations for borrowers as it does for on-balance sheet instruments. The following table is a summary of financial instrument commitments (in thousands): December 31, 2017 December 31, 2016 Fixed Variable Total Fixed Variable Total Letters of credit: Borrower: Financial standby $ 177 $ 3,770 $ 3,947 $ 137 $ 4,047 $ 4,184 Commercial standby - 354 354 - 126 126 Performance standby 241 7,594 7,835 83 8,499 8,582 418 11,718 12,136 220 12,672 12,892 Non-borrower: Performance standby - 142 142 95 524 619 Total letters of credit $ 418 $ 11,860 $ 12,278 $ 315 $ 13,196 $ 13,511 Unused loan commitments: $ 82,942 $ 260,061 $ 343,003 $ 68,996 $ 270,989 $ 339,985 The Bank occupies facilities under long-term operating leases, some of which include provisions for future rent increases. In addition, the Company leases space at sites that house automatic teller machines (ATMs). As of December 31, 2017, the estimated aggregate minimum annual rental commitments under these leases totaled $380,000 in 2018, $45,000 in 2019, $20,000 in 2020 and $6,000 in 2021. The Company also receives rental income on certain leased properties. As of December 31, 2017, aggregate future minimum rental income to be received under noncancelable leases totaled $232,000. Total facility net operating lease expense or revenue recorded under all operating leases was a net expense of $64,000 in 2017, net revenue $25,000 in 2016 and net expense of $11,000 in 2015. Total ATM lease expense, including the costs related to servicing those ATM’s, was $679,000, $685,000 and $826,000 in 2017, 2016 and 2015, respectively. Legal proceedings The Company and its subsidiaries, from time to time, pursue collection suits and other actions that arise in the ordinary course of business against their borrowers and are defendants in legal actions arising from normal business activities. Management, after consultation with legal counsel, believes that the ultimate liabilities, if any, resulting from these actions will not have a material adverse effect on the financial position of the Bank or on the consolidated financial position of the Company based on all known information at this time.

Regulatory & Capital Matters

Regulatory & Capital Matters	12 Months Ended
	Dec. 31, 2017
Regulatory & Capital Matters
Regulatory & Capital Matters	Note 16: Regulatory & Capital Matters The Bank is subject to the risk-based capital regulatory guidelines, which include the methodology for calculating the risk-weighted Bank assets, developed by the Office of the Comptroller of the Currency (the “OCC”) and the other bank regulatory agencies. In connection with the current economic environment, the Bank’s current level of nonperforming assets and the risk-based capital guidelines, the Bank’s board of directors’ guidelines are for the Bank to maintain a Tier 1 leverage capital ratio at or above eight percent (8%) and a total risk-based capital ratio at or above twelve percent (12%). The Bank currently exceeds those thresholds. Bank holding companies are required to maintain minimum levels of capital in accordance with capital guidelines implemented by the Board of Governors of the Federal Reserve System. The general bank and holding company capital adequacy guidelines in force as of the periods reported are shown in the accompanying table, as are the capital ratios of the Company and the Bank, as of December 31, 2017, and December 31, 2016. In July 2013, the U.S. federal banking authorities issued final rules (the “Basel III Rules”) establishing more stringent regulatory capital requirements for U.S. banking institutions, which went into effect on January 1, 2015. A detailed discussion of the Basel III Rules is included in Part I, Item 1 of the under the heading “Supervision and Regulation.” At December 31, 2017 and 2016, the Company, on a consolidated basis, exceeded the minimum thresholds to be considered “well capitalized” under current regulatory defined capital ratios. The Company and the Bank are subject to regulatory capital requirements administered by federal banking agencies. The capital ratios below are calculated pursuant to the capital requirements in effect for the periods reported below. Capital levels and industry defined regulatory minimum required levels: Minimum Capital To Be Well Capitalized Under Adequacy with Capital Prompt Corrective Actual Conservation Buffer if applicable 1 Action Provisions 2 Amount Ratio Amount Ratio Amount Ratio 2017 Common equity tier 1 capital to risk weighted assets Consolidated $ 179,853 9.25 % $ 111,801 5.750 % N/A N/A Old Second Bank 249,417 12.88 111,347 5.750 $ 125,870 6.50 % Total capital to risk weighted assets Consolidated 251,383 12.93 179,837 9.250 N/A N/A Old Second Bank 266,873 13.78 179,142 9.250 193,667 10.00 Tier 1 capital to risk weighted assets Consolidated 233,927 12.03 140,978 7.250 N/A N/A Old Second Bank 249,417 12.88 140,394 7.250 154,917 8.00 Tier 1 capital to average assets Consolidated 233,927 10.08 92,828 4.00 N/A N/A Old Second Bank 249,417 10.79 92,462 4.00 115,578 5.00 2016 Common equity tier 1 capital to risk weighted assets Consolidated $ 154,537 8.76 % $ 90,411 5.125 % N/A N/A Old Second Bank 221,153 12.53 90,456 5.125 $ 114,724 6.50 % Total capital to risk weighted assets Consolidated 216,769 12.29 152,126 8.625 N/A N/A Old Second Bank 237,306 13.45 152,176 8.625 176,436 10.00 Tier 1 capital to risk weighted assets Consolidated 191,988 10.88 116,904 6.625 N/A N/A Old Second Bank 221,153 12.53 116,930 6.625 141,199 8.00 Tier 1 capital to average assets Consolidated 191,988 8.90 86,287 4.00 N/A N/A Old Second Bank 221,153 10.24 86,388 4.00 107,985 5.00 1 As of December 31, 2017, amounts shown are inclusive of a capital conservation buffer of 1.25% as compared to December 31, 2016, of 0.625%. 2 The Bank exceeded the general minimum regulatory requirements to be considered “well capitalized” . Dividend Restrictions and Deferrals In addition to the above requirements, banking regulations and capital guidelines generally limit the amount of dividends that may be paid by a Bank without prior regulatory approval. Under these regulations, the amount of dividends that may be paid in any calendar year is limited to the current year’s profits, combined with the retained profit of the previous two years, subject to the capital requirements described above. Pursuant to the Basel III rules that came into effect January 1, 2015, the Bank must keep a buffer of 0.625% in 2016, 1.25% in 2017, 1.875% in 2018, and 2.5% in 2019 and thereafter of minimum capital requirements in order to avoid additional limitations on capital distributions.

Mortgage Banking Derivatives

Mortgage Banking Derivatives	12 Months Ended
	Dec. 31, 2017
Mortgage Banking Derivatives
Mortgage Banking Derivatives
Mortgage Banking Derivatives	Note 17: Mortgage Banking Derivatives Commitments to fund certain mortgage loans (interest rate locks) to be sold into the secondary market and forward commitments for the future delivery of mortgage loans to third party investors are considered derivatives. It is the Company’s practice to sell mortgage-backed securities (“MBS”) contracts for the future delivery to economically hedge the effect of changes in interest rates resulting from its commitments to fund the loans. These contracts are also derivatives and collectively with the forward commitments for the future delivery of mortgage loans are considered forward contracts. These mortgage banking derivatives are not designated in hedge relationships using the accepted accounting for derivative instruments and hedging activities at December 31 (dollars in thousands): 2017 2016 Forward contracts: Notional amount $ 16,500 $ 19,500 Fair value 3 190 Rate lock commitments: Notional amount $ 10,478 $ 12,480 Fair value 235 97 Fair values were estimated based on changes in mortgage interest rates from the date of the commitments. The Company sold $147.7 million in loans to investors receiving proceeds of $151.3 million and resulting in a gain on sale of $4.8 million for the year ended December 31, 2017, inclusive of a fair market valuation gain of $1.3 million. Sales to investors included $88.9 million or 60.3% to FNMA and $28.9 million, or 19.6% to FHLMC for the year ended December 31, 2017. No other individual investor was sold more than 10% of the total loans sold.

Fair Value Measurements

Fair Value Measurements	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements
Fair Value Measurements	Note 18: Fair Value Measurements Fair value is defined as the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The fair value hierarchy established by the Company also requires an entity to maximize the use of observable inputs and minimize the use of unobservable inputs when measuring fair value. Three levels of inputs that may be used to measure fair value are: Level 1: Quoted prices (unadjusted) for identical assets or liabilities in active markets that the Company has the ability to access as of the measurement date. Level 2: Significant observable inputs other than Level 1 prices, such as quoted prices for similar assets or liabilities, quoted prices in markets that are not active, and other inputs that are observable or can be corroborated by observable market data. Level 3: Significant unobservable inputs that reflect a company’s own view about the assumptions that market participants would use in pricing an asset or liability. Transfers between levels are deemed to have occurred at the end of the reporting period. At year end December 31,2017, the Company had no securities transferred from Level 2 to Level 3. The majority of securities are valued by external pricing services or dealer market participants and are classified in Level 2 of the fair value hierarchy. Both market and income valuation approaches are utilized. Quarterly, the Company evaluates the methodologies used by the external pricing services or dealer market participants to develop the fair values to determine whether the results of the valuations are representative of an exit price in the Company’s principal markets and an appropriate representation of fair value. The Company uses the following methods and significant assumptions to estimate fair value: · Government-sponsored agency debt securities are primarily priced using available market information through processes such as benchmark spreads, market valuations of like securities, like securities groupings and matrix pricing. · Other government-sponsored agency securities, MBS and some of the actively traded real estate mortgage investment conduits and collateralized mortgage obligations are priced using available market information including benchmark yields, prepayment speeds, spreads, volatility of similar securities and trade date. · State and political subdivisions are largely grouped by characteristics (e.g., geographical data and source of revenue in trade dissemination systems). Because some securities are not traded daily and due to other grouping limitations, active market quotes are often obtained using benchmarking for like securities. · Beginning March 31, 2015, auction rate asset backed securities are priced using market spreads, cash flows, prepayment speeds, and loss analytics. This process supports the transfer to Level 2 valuations. · Annually every security holding is priced by a pricing service independent of the regular and recurring pricing services used. The independent service provides a measurement to indicate if the price assigned by the regular service is within or outside of a reasonable range. Management reviews this report and applies judgment in adjusting calculations at year end related to securities pricing. · Residential mortgage loans available for sale in the secondary market are carried at fair market value. The fair value of loans held-for-sale is determined using quoted secondary market prices. · Lending related commitments to fund certain residential mortgage loans, e.g. residential mortgage loans with locked interest rates to be sold in the secondary market and forward commitments for the future delivery of mortgage loans to third party investors as well as forward commitments for future delivery of MBS are considered derivatives. Fair values are estimated based on observable changes in mortgage interest rates including prices for MBS from the date of the commitment and do not typically involve significant judgments by management. · The fair value of mortgage servicing rights is based on a valuation model that calculates the present value of estimated net servicing income. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income to derive the resultant value. The Company is able to compare the valuation model inputs, such as the discount rate, prepayment speeds, weighted average delinquency and foreclosure/bankruptcy rates to widely available published industry data for reasonableness. · Interest rate swap positions, both assets and liabilities, are based on valuation pricing models using an income approach reflecting readily observable market parameters such as interest rate yield curves. · The fair value of impaired loans with specific allocations of the ALLL is essentially based on recent real estate appraisals or the fair value of the collateralized asset. These appraisals may utilize a single valuation approach or a combination of approaches including comparable sales and the income approach. Adjustments are made in the appraisal process by the appraisers to reflect differences between the available comparable sales and income data. Such adjustments are usually significant and typically result in a Level 3 classification of the inputs for determining fair value. · Nonrecurring adjustments to certain commercial and residential real estate properties classified as OREO are measured at the lower of carrying amount or fair value, less costs to sell. Fair values are based on third party appraisals of the property, resulting in a Level 3 classification. In cases where the carrying amount exceeds the fair value, less costs to sell, an impairment loss is recognized. Assets and Liabilities Measured at Fair Value on a Recurring Basis : The tables below present the balance of assets and liabilities (dollars in thousands) at December 31, 2017, and December 31, 2016, respectively, measured by the Company at fair value on a recurring basis: December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Securities available-for-sale U.S. Treasury $ 3,947 $ - $ - $ 3,947 U.S. government agencies - 13,061 - 13,061 U.S. government agencies mortgage-backed - 12,214 - 12,214 States and political subdivisions - 263,831 14,261 278,092 Corporate bonds - 833 - 833 Collateralized mortgage obligations - 63,671 2,268 65,939 Asset-backed securities - 112,932 - 112,932 Collateralized loan obligations - 54,421 - 54,421 Loans held-for-sale - 4,067 - 4,067 Mortgage servicing rights - - 6,944 6,944 Interest rate swap agreements - 727 - 727 Mortgage banking derivatives - 238 - 238 Total $ 3,947 $ 525,995 $ 23,473 $ 553,415 Liabilities: Interest rate swap agreements, including risk participation agreements $ - $ 2,014 $ - $ 2,014 Total $ - $ 2,014 $ - $ 2,014 December 31, 2016 Level 1 Level 2 Level 3 Total Assets: Securities available-for-sale U.S. government agencies mortgage-backed $ - $ 41,534 $ - $ 41,534 States and political subdivisions - 46,477 22,226 68,703 Corporate bonds - 10,630 - 10,630 Collateralized mortgage obligations - 167,808 3,119 170,927 Asset-backed securities - 138,407 - 138,407 Collateralized loan obligations - 101,637 - 101,637 Loans held-for-sale - 4,918 - 4,918 Mortgage servicing rights - - 6,489 6,489 Interest rate swap agreements - 673 - 673 Mortgage banking derivatives - 287 - 287 Total $ - $ 512,371 $ 31,834 $ 544,205 Liabilities: Interest rate swap agreements, including risk participation agreements $ - $ 1,667 $ - $ 1,667 Total $ - $ 1,667 $ - $ 1,667 The changes in Level 3 assets and liabilities (dollars in thousands) measured at fair value on a recurring basis are as follows: Year Ended December 31, 2017 Securities available-for-sale Collateralized States and Mortgage Mortgage Political Servicing Obligation Subdivisions Rights Beginning balance January 1, 2017 $ 3,119 $ 22,226 $ 6,489 Total gains or losses Included in earnings (or changes in net assets) 40 - (270) Included in other comprehensive income 21 (796) - Purchases, issuances, sales, and settlements Purchases - 16,712 - Issuances - - 1,257 Settlements (912) (23,881) (532) Ending balance December 31, 2017 $ 2,268 $ 14,261 $ 6,944 Year Ended December 31, 2016 Securities available-for-sale Collateralized States and Mortgage Mortgage Political Servicing Obligation Subdivisions Rights Beginning balance January 1, 2016 $ - $ 111 $ 5,847 Transfers into Level 3 3,201 7,813 - Total gains or losses Included in earnings (or changes in net assets) - - (215) Included in other comprehensive income (82) 87 - Purchases, issuances, sales, and settlements Purchases - 14,296 - Issuances - - 1,561 Settlements - (81) (704) Ending balance December 31, 2016 $ 3,119 $ 22,226 $ 6,489 The following table and commentary presents quantitative (dollars in thousands) and qualitative information about Level 3 fair value measurements as of December 31, 2017: Weighted Measured at fair value Unobservable Average on a recurring basis: Fair Value Valuation Methodology Inputs Range of Input of Inputs Mortgage servicing rights $ 6,944 Discounted Cash Flow Discount Rate 10.0 - 34.3% 10.2 % Prepayment Speed 7.0 - 68.4% 9.6 % The following table and commentary presents quantitative (dollars in thousands) and qualitative information about Level 3 fair value measurements as of December 31, 2016: Weighted Measured at fair value Unobservable Average on a recurring basis: Fair Value Valuation Methodology Inputs Range of Input of Inputs Mortgage servicing rights $ 6,489 Discounted Cash Flow Discount Rate 10.0 - 17.0% 10.2 % Prepayment Speed 6.5 - 77.8% 9.6 % In addition to the above, Level 3 fair value measurement included $14.3 million for state and political subdivisions representing various local municipality securities and $2.3 million of collateralized mortgage obligations at December 31, 2017. Level 3 fair value measurement included $22.2 million on the state and political subdivisions line and $3.1 million of collateralized mortgage obligations at December 31, 2016. Given the small dollar amount and size of the municipality involved, this is categorized as Level 3 based on the payment stream received by the Company from the municipality. That payment stream is otherwise an unobservable input. Assets and Liabilities Measured at Fair Value on a Nonrecurring Basis: The Company may be required, from time to time, to measure certain other assets at fair value on a nonrecurring basis in accordance with GAAP. These assets consist of impaired loans and OREO. For assets measured at fair value on a nonrecurring basis at December 31, 2017, and December 31, 2016, respectively, the following tables provide the level of valuation assumptions used to determine each valuation and the carrying value of the related assets: December 31, 2017 Level 1 Level 2 Level 3 Total Impaired loans 1 $ - $ - $ 5,113 $ 5,113 Other real estate owned, net 2 - - 8,371 8,371 Total $ - $ - $ 13,484 $ 13,484 1 Represents carrying value and related write-downs of loans for which adjustments are substantially based on the appraised value of collateral for collateral-dependent loans, had a carrying amount of $5.3 million and a valuation allowance of $144,000, resulting in an increase of specific allocations within the ALLL of $856,000 for the year ending December 31, 2017. 2 OREO is measured at the lower of carrying or fair value less costs to sell, and had a net carrying amount of $8.4 million, which is made up of the outstanding balance of $17.4 million, net of a valuation allowance of $8.2 million and participations of $900,000, at December 31, 2017. December 31, 2016 Level 1 Level 2 Level 3 Total Impaired loans 1 $ - $ - $ - $ - Other real estate owned, net 2 - - 11,916 11,916 Total $ - $ - $ 11,916 $ 11,916 1 Represents carrying value and related write-downs of loans for which adjustments are substantially based on the appraised value of collateral for collateral-dependent loans, had a carrying amount and a valuation allowance of $1.0, resulting in a decrease of specific allocations within the provision for loan and lease losses of $1.0 million for the year ending December 31, 2016. 2 OREO is measured at the lower of carrying or fair value less costs to sell, and had a net carrying amount of $11.9 million, which is made up of the outstanding balance of $23.5 million, net of a valuation allowance of $14.1 million and participations of $1.7 million, at December 31, 2016. The Company also has assets that under certain conditions are subject to measurement at fair value on a nonrecurring basis. These assets include OREO and impaired loans. The Company has estimated the fair values of these assets based primarily on Level 3 inputs. OREO and impaired loans are generally valued using the fair value of collateral provided by third party appraisals. These valuations include assumptions related to cash flow projections, discount rates, and recent comparable sales. The numerical range of unobservable inputs for these valuation assumptions are not meaningful.

Fair Values of Financial Instru

Fair Values of Financial Instruments	12 Months Ended
	Dec. 31, 2017
Fair Values of Financial Instruments
Fair Values of Financial Instruments	Note 19: Fair Values of Financial Instruments The estimated fair values approximate carrying amount for all items except those described in the following table. Investment security fair values are based upon market prices or dealer quotes, and if no such information is available, on the rate and term of the security. The carrying value of FHLBC stock approximates fair value as the stock is nonmarketable and can only be sold to the FHLBC or another member institution at par. During the years ended December 31, 2017 and 2016, the Company participated in redemptions and purchases with the FHLBC and, using these transactions values as the carrying value, FHLBC stock is carried at a Level 2 fair value. Fair values of loans were estimated for portfolios of loans with similar financial characteristics, such as type and fixed or variable interest rate terms. Cash flows were discounted using current rates at which similar loans would be made to borrowers with similar ratings and for similar maturities. The fair value of time deposits is estimated using discounted future cash flows at current rates offered for deposits of similar remaining maturities. The fair values of borrowings were estimated based on interest rates available to the Company for debt with similar terms and remaining maturities. The fair value of off balance sheet volume is not considered material. The fair value of mortgage banking derivatives is discussed above in Note 17. The carrying amount and estimated fair values of financial instruments were as follows: December 31, 2017 Carrying Fair Amount Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 37,444 $ 37,444 $ 37,444 $ - $ - Interest bearing deposits with financial institutions 18,389 18,389 18,389 - - Securities available-for-sale 541,439 541,439 3,947 520,963 16,529 FHLBC and FRBC Stock 10,168 10,168 - 10,168 - Loans held-for-sale 4,067 4,067 - 4,067 - Loans, net 1,600,161 1,586,722 - - 1,586,722 Accrued interest receivable 8,595 8,595 - 8,595 - Financial liabilities: Noninterest bearing deposits $ 572,404 $ 572,404 $ 572,404 $ - $ - Interest bearing deposits 1,350,521 1,346,339 - 1,346,339 - Securities sold under repurchase agreements 29,918 29,918 - 29,918 - Other short-term borrowings 115,000 115,000 - 115,000 - Junior subordinated debentures 57,639 59,471 33,267 26,204 - Senior notes 44,058 46,743 - 46,743 - Interest rate swap agreements 1,287 1,287 - 1,287 - Borrowing interest payable 140 140 - 140 - Deposit interest payable 631 631 - 631 - December 31, 2016 Carrying Fair Amount Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 33,805 $ 33,805 $ 33,805 $ - $ - Interest bearing deposits with financial institutions 13,529 13,529 13,529 - - Securities available-for-sale 531,838 531,838 - 506,493 25,345 FHLBC and FRBC Stock 7,918 7,918 - 7,918 - Loans held-for-sale 4,918 4,918 - 4,918 - Loans, net 1,462,651 1,453,429 - - 1,453,429 Accrued interest receivable 5,928 5,928 - 5,928 - Financial liabilities: Noninterest bearing deposits $ 513,688 $ 513,688 $ 513,688 $ - $ - Interest bearing deposits 1,353,097 1,351,000 - 1,351,000 - Securities sold under repurchase agreements 25,715 25,715 - 25,715 - Other short-term borrowings 70,000 70,000 - 70,000 - Junior subordinated debentures 57,591 55,163 32,404 22,759 - Subordinated debenture 43,998 43,998 - 43,998 - Interest rate swap agreements 994 994 - 994 - Borrowing interest payable 202 202 - 202 - Deposit interest payable 599 599 - 599 -

Financial Instruments with Off-

Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions	12 Months Ended
	Dec. 31, 2017
Derivative Excluding Mortgage Banking Derivatives
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions	Note 20: Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions To meet the financing needs of its customers, the Bank, as a subsidiary of the Company, is a party to various financial instruments with off-balance-sheet risk in the normal course of business. These off-balance-sheet financial instruments include commitments to originate and sell loans as well as financial standby, performance standby and commercial letters of credit. The instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the consolidated balance sheet. The Bank’s exposure to credit loss for loan commitments and letters of credit is represented by the dollar amount of those instruments. Management generally uses the same credit policies and collateral requirements in making commitments and conditional obligations as it does for on-balance-sheet instruments. Interest Rate Swap Designated as a Cash Flow Hedge The Company entered into a forward starting interest rate swap on August 18, 2015, with an effective date of June 15, 2017. This transaction had a notional amount totaling $25.8 million as of December 31, 2017, was designated as a cash flow hedge of certain junior subordinated debentures and was determined to be fully effective during the period presented. As such, no amount of ineffectiveness has been included in net income. Therefore, the aggregate fair value of the swap is recorded in other liabilities with changes in fair value recorded in other comprehensive income, net of tax. The amount included in other comprehensive income would be reclassified to current earnings should all or a portion of the hedge no longer be considered effective. The Company expects the hedge to remain fully effective during the remaining term of the swap. The Bank will pay the counterparty a fixed rate and receive a floating rate based on three month LIBOR. Management concluded that it would be advantageous to enter into this transaction given that the Company has trust preferred securities that will change from fixed rate to floating rate on June 15, 2017. The cash flow hedge has a maturity date of June 15, 2037. Summary information about the interest rate swap designated as a cash flow hedge is as follows: As of December 31, 2017 December 31, 2016 Notional amount $ 25,774 $ 25,774 Unrealized loss (1,287) (994) Interest Rate Swaps The Bank also has interest rate derivative positions to assist with risk management that are not designated as hedging instruments. These derivative positions relate to transactions in which the Bank enters an interest rate swap with a client while at the same time entering into an offsetting interest rate swap with another financial institution. Due to financial covenant violations relating to nonperforming loans, the Bank had $4.2 million in investment securities pledged to support interest rate swap activity with two correspondent financial institutions at December 31, 2017. The Bank had $6.2 million in investment securities pledged to support interest rate swap activity with three correspondent financial institutions at December 31, 2016. In connection with each transaction, the Bank agreed to pay interest to the client on a notional amount at a variable interest rate and receive interest from the client on the same notional amount at a fixed interest rate. At the same time, the Bank agreed to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows the client to convert a variable rate loan to a fixed rate loan and is part of the Company’s interest rate risk management strategy. Because the Bank acts as an intermediary for the client, changes in the fair value of the underlying derivative contracts offset each other and do not generally affect the results of operations. At December 31, 2017, the notional amount of non-hedging interest rate swaps was $153.4 million with a weighted average maturity of 6.6 years. At December 31, 2016, the notional amount of non-hedging interest rate swaps was $85.8 million with a weighted average maturity of 7.3 years. The Bank offsets derivative assets and liabilities that are subject to a master netting arrangement. The Bank also grants mortgage loan interest rate lock commitments to borrowers, subject to normal loan underwriting standards. The interest rate risk associated with these loan interest rate lock commitments is managed with contracts for future deliveries of loans as well as selling forward mortgage-backed securities contracts. Loan interest rate lock commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since a portion of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. Commitments to originate residential mortgage loans held-for-sale and forward commitments to sell residential mortgage loans or forward MBS contracts are considered derivative instruments and changes in the fair value are recorded to mortgage banking revenue. Fair values are estimated based on observable changes in mortgage interest rates including mortgage-backed securities prices from the date of the commitment. The following table presents derivatives not designated as hedging instruments as of December 31, 2017, and periodic changes in the values of the interest rate swaps are reported in other noninterest income. Periodic changes in the value of the forward contracts related to mortgage loan origination are reported in the net gain on sales of mortgage loans. Asset Derivatives Liability Derivatives Notional or Contractual Balance Sheet Balance Sheet Amount Location Fair Value Location Fair Value Interest rate swap contracts net of credit valuation $ 153,433 Other Assets $ 727 Other Liabilities $ 727 Interest rate lock commitments and forward contracts 26,978 Other Assets 238 N/A - Total $ 965 $ 727 The following table presents derivatives not designated as hedging instruments as of December 31, 2016. Asset Derivatives Liability Derivatives Notional or Contractual Balance Sheet Balance Sheet Amount Location Fair Value Location Fair Value Interest rate swap contracts net of credit valuation $ 85,807 Other Assets $ 673 Other Liabilities $ 673 Interest rate lock commitments and forward contracts 31,980 Other Assets 287 N/A - Total $ 960 $ 673

Preferred Stock

Preferred Stock	12 Months Ended
	Dec. 31, 2017
Preferred Stock.
Preferred Stock	Note 21: Preferred Stock The Series B Stock preferred stock was issued as part of the Treasury’s Troubled Asset Relief Program and Capital Purchase Program in 2009. Concurrent with issuing the Series B Stock in 2009, the Company issued to the Treasury a ten year warrant to purchase 815,339 shares of the Company’s common stock at an exercise price of $13.43 per share. The Company recorded the warrant as equity, and the allocation was based on their relative fair values in accordance with accounting guidance. The fair value was determined for both the Series B Stock and the warrant as part of the allocation process in the amounts of $68.2 million and $4.8 million, respectively. In 2014 and 2015, the Company completed redemption of all 73,000 shares of Series B Stock preferred stock issued in 2009. As of December 31, 2017 and 2016, the only remaining component of the 2009 issuance is the warrant outstanding for 815,339 shares, valued at $4.8 million and carried within stockholders’ equity. Preferred stock of 300,000 shares is authorized but unissued as of December 31, 2017 and 2016.

Parent Company Condensed Financ

Parent Company Condensed Financial Information	12 Months Ended
	Dec. 31, 2017
Parent Company Condensed Financial Information
Parent Company Condensed Financial Information	Note 22: Parent Company Condensed Financial Information Condensed Balance Sheets as of December 31 were as follows: 2017 2016 Assets Noninterest bearing deposit with bank subsidiary $ 23,011 $ 26,925 Investment in subsidiaries 263,389 228,646 Other assets 17,139 23,304 Total assets $ 303,539 $ 278,875 Liabilities and Stockholders’ Equity Junior subordinated debentures $ 57,639 $ 57,591 Senior notes 44,058 43,998 Other liabilities 1,492 2,076 Stockholders’ equity 200,350 175,210 Total liabilities and stockholders' equity $ 303,539 $ 278,875 Condensed Statements of Income for the years ended December 31 were as follows: 2017 2016 2015 Operating Income Cash dividends received from subsidiaries $ - $ - $ 82,777 Other income 114 130 131 Total operating income 114 130 82,908 Operating Expenses Junior subordinated debentures 4,002 4,334 4,287 Senior notes 2,689 112 - Subordinated debt - 949 814 Other interest expense - 8 7 Other expenses 2,639 1,975 1,978 Total operating expense 9,330 7,378 7,086 Loss before income taxes and equity in undistributed net income of subsidiaries (9,216) (7,248) 75,822 Income tax benefit (16) (2,909) (2,771) Loss before equity in undistributed net income of subsidiaries (9,200) (4,339) 78,593 Equity in undistributed (over distributed) net income of subsidiaries 24,338 20,023 (63,208) Net income 15,138 15,684 15,385 Preferred stock dividends and accretion of discount - - 1,873 Net income available to common stockholders $ 15,138 $ 15,684 $ 13,512 Condensed Statements of Cash Flows for the years ended December 31 were as follows: 2017 2016 2015 Cash Flows from Operating Activities Net Income $ 15,138 $ 15,684 $ 15,385 Adjustments to reconcile net income to net cash from operating activities: Equity in (undistributed) over distributed net income of subsidiaries (24,338) (20,023) 63,208 Provision for deferred tax expense (benefit) 6,397 (1,039) (2,806) Net deferred tax expense due to DTA revaluation 3,908 - - Change in taxes payable (4,797) 330 (199) Change in other assets 74 171 36 Stock-based compensation 1,181 657 613 Other, net (15) 282 69 Net cash (used in) provided by operating activities (2,452) (3,938) 76,306 Cash Flows from Investing Activities Net cash provided by investing activities - - - Cash Flows from Financing Activities Dividend paid on preferred stock - - (2,417) Dividend paid on common stock (1,184) (888) - Purchases of treasury stock (236) (254) (117) Proceeds from the issuance of common stock - - - Proceeds from the issuance of senior notes - 43,994 - Payment of senior note issuance costs (42) - - Repayment of subordinated debt - (45,000) - Repayment of note payable - (500) - Proceeds from exercise of stock option - 11 - Redemption of preferred stock - - (47,331) Net cash used in financing activities (1,462) (2,637) (49,865) Net change in cash and cash equivalents (3,914) (6,575) 26,441 Cash and cash equivalents at beginning of year 26,925 33,500 7,059 Cash and cash equivalents at end of year $ 23,011 $ 26,925 $ 33,500

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2017
Employee Benefit Plans
Employee Benefit Plans	Note 23: Employee Benefit Plans Old Second Bancorp, Inc. Employees 401(k) Savings Plan and Trust The Company sponsors a qualified, tax-exempt defined contribution plan (the “Plan”) qualifying under section 401(k) of the Internal Revenue Code. Virtually all employees are eligible to participate after meeting certain age and service requirements. Eligible employees are permitted to contribute up to a dollar limit set by law of their compensation to the Plan. For the years ended December 31, 2017, 2016 and 2015, a discretionary match equal to 100% of the first 3% of the participant’s compensation was contributed to participants of the Plan. Participants are 100% vested in the discretionary matching contributions. Participants can choose between several different investment options under the Plan, including shares of the Company’s common stock. An additional component of the Plan arrangement allows for the Company to make annual discretionary contributions under a profit sharing portion based on the Company’s profitability in a given year, and on each participant’s annual compensation. The Company elected not to make a discretionary profit sharing contribution for the years end December 31, 2017, 2016 and 2015. The total expense relating to the Plan was approximately $698,000, $464,000 and $477,000 in 2017, 2016 and 2015, respectively. Old Second Bancorp, Inc. Voluntary Deferred Compensation Plan for Executives The Company sponsors an executive deferred compensation plan, which is a means by which certain executives may voluntarily defer a portion of their salary or bonus. This plan is an unfunded, nonqualified deferred compensation arrangement. Company obligations under this arrangement as of December 31, 2017, 2016 and 2015 were $1.7 million, $1.6 million and $1.9 million, respectively, and are included in other liabilities.

Summary of Significant Accoun31

Summary of Significant Accounting Policies (Policies)-10K	12 Months Ended
	Dec. 31, 2017
Summary of Significant Accounting Policies
Basis of presentation	The consolidated financial statements of Old Second Bancorp, Inc., and Subsidiaries (the “Company”) include the financial statements of Old Second Bancorp, Inc., a registered bank holding company, and its wholly-owned bank, Old Second National Bank (the “Bank”). The Company uses the accrual basis of accounting for financial reporting purposes. Certain amounts in prior year financial statements have been reclassified to conform to the 2017 presentation.
Use of Estimates	Use of Estimates – The preparation of consolidated financial statements in conformity with generally accepted accounting principles (“GAAP”) and following general practices within the banking industry requires management to make estimates and assumptions that affect the amounts reported in the consolidated financial statements and accompanying notes. Although these estimates and assumptions are based on the best available information, actual results could differ from those estimates.
Principles of Consolidation	Principles of Consolidation – The accompanying consolidated financial statements include the accounts and results of operations of the Company and its subsidiaries after elimination of all significant intercompany accounts and transactions. Assets held in a fiduciary or agency capacity are not assets of the Company or its subsidiaries and are not included in the consolidated financial statements.
Segment Reporting	Segment Reporting – An operating segment is a component of a business entity that engages in business activity from which it may earn revenues and/or incur expenses. It has operating results that are reviewed regularly by the entity’s chief operating decision maker in order to make decisions about resource allocation and performance assessment, and the segment has discrete financial information available for this assessment. As of December 31, 2017, the Company had one operating segment, which is community banking. Therefore, segment reporting is not required
Cash and Cash Equivalents	Cash and Cash Equivalents – For purposes of the Consolidated Statements of Cash Flows, management has defined cash and cash equivalents to include cash and due from banks, interest-bearing deposits in other banks, and other short-term investments, such as federal funds sold and securities purchased under agreements to resell.
Securities	Securities – Securities are classified as available-for-sale or held-to-maturity at the time of purchase or transfer. Securities that are classified as available-for-sale are carried at fair value. Unrealized gains and losses, net of related deferred income taxes, are recorded in stockholders’ equity as a separate component of accumulated other comprehensive income or loss. Unrealized gains and losses are not included in the calculation of regulatory capital. Securities held-to-maturity are carried at amortized cost and the discount or premium created at acquisition or in the transfer from available-for-sale is accreted or amortized to the maturity or expected payoff date but not an earlier call. Discounts are accreted into interest income over the estimated life of the related security and premiums are amortized into income to the earlier of the call date or estimated life of the related security using the level yield method. Purchases and sales of securities are recognized on a trade date basis. Realized securities gains or losses are reported in securities gains (losses), net, in the Consolidated Statements of Income. The cost of securities sold is based on the specific identification method. On a quarterly basis, the Company makes an assessment (at the individual security level) to determine whether there have been any events or circumstances indicating that a security with an unrealized loss is other-than-temporarily impaired (“OTTI”). In evaluating OTTI, the Company considers many factors, including the severity and duration of the impairment; the financial condition and near-term prospects of the issuer, which for debt securities considers external credit ratings and recent downgrades; its ability and intent to hold the security for a period of time sufficient for a recovery in value; and the likelihood that it will be required to sell the security before a recovery in value, which may be at maturity. The amount of the impairment related to other factors is recognized in other comprehensive income (loss) unless management intends to sell the security or believes it is more likely than not that it will be required to sell the security prior to full recovery.
Federal Home Loan Bank and Federal Reserve Bank Stock	Federal Home Loan Bank and Federal Reserve Bank Stock – The Company owns the stock of the Federal Home Loan Bank of Chicago (“FHLBC”) and the Federal Reserve Bank of Chicago (“FRBC”). Both of these entities require the Bank to invest in their nonmarketable stock as a condition of membership. The FHLBC is a governmental sponsored entity. The Bank continues to utilize the various products and services of the FHLBC and management considers this stock to be a long-term investment. FHLBC members are required to own a certain amount of stock based on the level of borrowings and other factors, and may invest in additional amounts. FHLBC stock is carried at cost, classified as a restricted security, and periodically evaluated for impairment based on ultimate recovery of par value. The Company’s ability to redeem the shares owned is dependent on the redemption practices of the FHLBC. The Company records dividends in income on the ex-dividend date. FRBC stock is redeemable at par, and therefore fair value equals cost.
Loans Held-for-Sale	Loans Held-for-Sale – The Bank originates residential mortgage loans, which consist of loan products eligible for sale to the secondary market. Residential mortgage loans eligible for sale in the secondary market are carried at fair market value. The fair value of loans held-for-sale is determined using quoted secondary market prices on similar loans.
Loans	Loans – Loans held-for-investment are carried at the principal amount outstanding, including certain net deferred loan origination fees and costs. Acquired loans were assessed for credit impairment upon acquisition. As no impairment was noted, the loans are carried at the purchased amount, less any purchase accounting discount recorded to mark the loans to fair value. If impairment was noted, the purchase accounting credit mark accretion would be discontinued, and the loan would be evaluated for charge-off to be taken against the remaining mark. Interest income on loans is accrued based on principal amounts outstanding. Loan and lease origination fees, commitment fees, and certain direct loan origination costs are deferred and amortized over the life of the related loans or commitments as a yield adjustment. The acquisition adjustment discount related to purchased loans is accreted into interest income over the contractual life of each loan, or is generally taken into income immediately upon payoff or renewal of the loan. Fees related to standby letters of credit, whose ultimate exercise is remote, are amortized into fee income over the estimated life of the commitment. Other credit-related fees are recognized as fee income when earned.
Lease financing receivables	Lease Financing Receivables – Lease financing receivables are subject to underwriting standards and processes similar to commercial loans. These loans are often secured by equipment or transportation assets, and are made based primarily on the historical and projected cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not behave as forecasted and collateral securing loans may fluctuate in value due to economic or individual performance factors.
Concentration of Credit Risk	Concentration of Credit Risk – Most of the Company’s business activity is with customers located within Kane, Kendall, DeKalb, DuPage, LaSalle, Will and Cook counties in Illinois. These banking centers surround or are within the Chicago metropolitan area. Therefore, the Company’s exposure to credit risk is significantly affected by changes in the economy in that market area since the Bank generally makes loans within its market. There are no significant concentrations of loans where the customers’ ability to honor loan terms is dependent upon a single economic sector.
Nonaccrual loans	Nonaccrual Loans – Generally, commercial and consumer loans, as well as loans secured by real estate are placed on nonaccrual status (i) when either principal or interest payments become 90 days or more past due based on contractual terms unless the loan is sufficiently collateralized such that full repayment of both principal and interest is expected and is in the process of collection within a reasonable period or (ii) when an individual analysis of a borrower’s creditworthiness indicates a credit should be placed on nonaccrual status whether or not the loan is 90 days or more past due. When a loan is placed on nonaccrual status, unpaid interest credited to income is reversed. Generally, after the loan is placed on nonaccrual, all debt service payments are applied to the principal on the loan. Nonaccrual loans are returned to accrual status when the financial position of the borrower and other relevant factors indicate there is no longer doubt that the Company will collect all principal and interest due. Commercial, consumer and real estate loans are generally charged-off when deemed uncollectible. A loss is recorded at that time if the net realizable value can be quantified and it is less than the associated principal outstanding.
Troubled Debt Restructurings (TDRs)	Troubled Debt Restructurings (“TDRs”) – A restructuring of debt is considered a TDR when (i) the borrower is experiencing financial difficulties and (ii) the creditor grants a concession, such as forgiveness of principal, reduction of the interest rate, changes in payments, or extension of the maturity, that it would not otherwise consider. Loans are not classified as TDRs when the modification is short-term or results in only an insignificant delay or shortfall in the payments to be received. The Company’s TDRs are determined on a case-by-case basis in connection with ongoing loan collection processes. The Company does not accrue interest on any TDRs unless it believes collection of all principal and interest under the modified terms is reasonably assured. For TDRs to accrue interest, the borrower must demonstrate both some level of past performance and the capacity to perform under the modified terms. Generally, six months of consecutive payment performance by the borrower under the restructured terms is required before TDRs are returned to accrual status. However, the period could vary depending on the individual facts and circumstances of the loan. An evaluation of the borrower’s current creditworthiness is used to assess whether the borrower has the capacity to repay the loan under the modified terms. This evaluation includes an estimate of expected cash flows, evidence of strong financial position, and estimates of the value of collateral, if applicable.
Impaired Loans	Impaired Loans – Impaired loans consist of nonaccrual loans and TDRs (both accruing and on nonaccrual). A loan is considered impaired when it is probable that the Company will be unable to collect all contractual principal and interest due according to the terms of the loan agreement based on current information and events. With the exception of TDRs still accruing interest, loans deemed to be impaired are classified as nonaccrual and are exclusive of smaller homogeneous loans, such as home equity, 1-4 family mortgages, and consumer loans.
90-Days or Greater Past Due Loans	90-Days or Greater Past Due Loans – 90-days or greater past due loans are loans with principal or interest payments three months or more past due, but that still accrue interest. The Company continues to accrue interest if it determines these loans are sufficiently collateralized and the process of collection will conclude within a reasonable time period.
Allowance for Loan Losses	Allowance for Loan and Lease Losses (“ALLL”) – The ALLL is calculated according to GAAP standards and is maintained by management at a level believed adequate to absorb estimated losses inherent in the existing loan portfolio. Determination of the ALLL is inherently subjective since it requires significant estimates and management judgment, and includes a level of imprecision given the difficulty of identifying and assessing the factors impacting loan repayment and estimating the timing and amount of losses. While management utilizes its best judgment and information available, the ultimate adequacy of the ALLL is dependent upon a variety of factors beyond the Company’s direct control, including the performance of the loan portfolio, consideration of current economic trends, changes in interest rates and property values, the amounts and timing of expected future cash flows on impaired loans, estimated losses on pools of homogeneous loans based on an analysis that uses historical loss experience, portfolio growth and concentration risk, management and staffing changes, the interpretation of loan risk classifications by regulatory authorities and other credit market factors. While each component of the ALLL is determined separately, the entire balance is available for the entire loan portfolio. Loans deemed to be uncollectible are charged-off against the ALLL while recoveries of amounts previously charged-off are credited to the ALLL. Approved releases from previously established loan loss reserves authorized under our allowance methodology also reduce the ALLL. Additions to the allowance are established through the provision for loan and lease losses charged to expense. The ALLL methodology consists of (i) specific reserves established for probable losses on individual loans for which the recorded investment in the loan exceeds the present value of expected future cash flows or the net realizable value of the underlying collateral, if collateral dependent, (ii) an allowance based on a historical loss analysis that uses credit loss experience for the prior 20 quarters for each loan category, and (iii) the impact of other internal and external qualitative and credit market factors as assessed by management through detailed loan review, allowance analysis and credit discussions. In 2016, the Company significantly refined its ALLL methodology to further stratify the loan portfolio and apply unique factors to each segment. The changes implemented in 2016 segregate the total loan portfolio into further detail, moving from seven loan classifications to nine when applying management risk factors, and from four loan classifications to nine when applying historical loss rates. The Company also enhanced the prior process of applying management risk factors for changes in loans portfolio trends, such as factors for changes in the trend or volume of past due and classified loans, changes in the nature and volume of the portfolio and concentrations, changes in lending policy, procedures, management and staffing, and other external factors. These factors were historically analyzed in the aggregate to arrive at one risk factor per loan classification; under the revised methodology, the Company assigns each of these components its own risk factor, as well as encompasses an additional risk rating for loans rated as pass/watch. The Company continued to refine its ALLL methodology in 2017, with implementation of additional management factor classifications for newer loan portfolios, such as the Company’s recent purchase of home equity lines of credit (“HELOCs”) and the recently expanded business development company loan portfolio, as these portfolios have not been outstanding long enough to be sufficiently seasoned. In addition, the Company revised the risk weightings for the historical loss factors to reflect a five basis point increase to the loss factor applied in the earliest quarter, and a reduction of five basis points in the most recent quarter, as management believes the lower charge-off levels in the more recent quarters will likely not continue long-term. These modifications to the Company’s ALLL methodology are intended to more accurately reflect all portfolio risk, and resulted in a decrease to the overall unallocated component of the allowance over the past two years. The unallocated component of the allowance was $542,000 as of December 31, 2017, compared to $435,000 as of December 31, 2016 and $2.0 million as of December 31, 2015. All calculations conform to GAAP.
Premises and Equipment	Premises and Equipment – Premises, furniture, equipment, and leasehold improvements are stated at cost less accumulated depreciation and amortization. Depreciation expense is determined by the straight-line method over the estimated useful lives of the assets. Leasehold improvements are amortized on a straight-line basis over the shorter of the life of the asset or the lease term including anticipated renewals. Rates of depreciation are generally based on the following useful lives: buildings, 25 to 40 years; building improvements, 3 to 15 years or longer under limited circumstances; and furniture and equipment, 3 to 10 years. Gains and losses on dispositions are included in other noninterest income in the Consolidated Statements of Income. Maintenance and repairs are charged to operating expenses as incurred, while improvements that conform to definitions of tangible property improvements are capitalized and depreciated over the estimated remaining life.
Other Real Estate Owned ("OREO")	Other Real Estate Owned (“OREO”) – Real estate assets acquired in settlement of loans are recorded at the fair value of the property when acquired, less estimated costs to sell, establishing a new cost basis. Physical possession of residential real estate property collateralizing a consumer mortgage loan occurs when legal title is obtained upon foreclosure or when the borrower conveys all interest in the property to satisfy the loan through completion of a deed in lieu of foreclosure or through a similar legal agreement. Any deficiency between the net book value and fair value at the foreclosure or deed in lieu date is charged to the ALLL. If fair value subsequently declines, an OREO valuation allowance is established for the decrease between the recorded value and the updated fair value less costs to sell. Such declines are included in other noninterest expense in the Consolidated Statements of Income. A subsequent reversal of an OREO valuation adjustment can occur, but the resultant carrying value cannot exceed the cost basis established at transfer of the loan to OREO. Operating costs after acquisition are also expensed.
Mortgage Servicing Rights	Mortgage Servicing Rights – The Bank is also involved in the business of servicing mortgage loans. Servicing activities include collecting principal, interest, and escrow payments from borrowers, making tax and insurance payments on behalf of the borrowers, monitoring delinquencies, executing foreclosure proceedings, and accounting for and remitting principal and interest payments to the investors. Mortgage servicing rights represent the right to a stream of cash flows and an obligation to perform specified residential mortgage servicing activities. Mortgage loans that the Company is servicing for others aggregated to $695.1 million and $668.2 million at December 31, 2017, and 2016, respectively. Mortgage loans that the Company is servicing for others are not included in the consolidated balance sheets. Fees received in connection with servicing loans for others are recognized as earned. Loan servicing costs are charged to expense as incurred. Servicing rights are recognized separately as assets when they are acquired through sales of loans and servicing rights are retained. Servicing rights are initially recorded at fair value with the effect recorded in net gains on sales of mortgage loans in the Consolidated Statements of Income. 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. The valuation model incorporates assumptions that market participants would use in estimating future net servicing income, such as the cost to service, the discount rate, the custodial earnings rate, an inflation rate, ancillary income, prepayment speeds and default rates and losses. Servicing fee income, which is included in the Consolidated Statements of Income as mortgage servicing income, is recorded for fees earned for servicing loans. The fees are based on a contractual percentage of the outstanding principal or a fixed amount per loan and are recorded as income when earned. Under the fair value measurement method, the Company measures mortgage servicing rights at fair value at each reporting date, reports changes in fair value of servicing assets in earnings in the period in which the changes occur, and includes these changes in mortgage servicing rights mark to market in the Consolidated Statements of Income. The fair values of mortgage servicing rights are subject to significant fluctuations as a result of changes in estimated and actual prepayment speeds and default rates and losses.
Bank-Owned Life Insurance ("BOLI")	Bank-Owned Life Insurance (“BOLI”) – BOLI represents life insurance policies on the lives of certain Company employees (both current and former) for which the Company is the sole owner and beneficiary. These policies are recorded as an asset on the Consolidated Balance Sheets at their cash surrender value (“CSV”) or the amount that could be realized. The change in CSV and insurance proceeds received are recorded as an increase in cash surrender value of bank-owned life insurance in the Consolidated Statements of Income in noninterest income.
Goodwill and Core Deposit Intangible Assets	Goodwill and Core Deposit Intangible – Goodwill is the excess of an acquisition’s purchase price over the fair value of identified net assets acquired in an acquisition. Goodwill is not deemed to have definitive life span, and therefore is not amortized, but is subject to annual review for impairment. The core deposit intangible (“CDI”) is being amortized on an accelerated method over a ten year estimated useful life.
Loss Contingencies	Debt Issuance Costs – Costs associated with the issuance of debt are presented in the Consolidated Balance Sheet as a direct reduction from the carrying value of that debt liability. The deferred issuance costs are amortized over the life the related debt instrument, and included within the debt’s interest expense. Loss Contingencies – Loss contingencies, including claims and legal actions arising in the ordinary course of business, are recorded as liabilities when the likelihood of loss is probable and an amount or range of loss can be reasonably estimated. Management does not believe there are such matters that will have a material effect on the financial statements.
Wealth Management	Wealth Management – Assets held in a fiduciary or agency capacity for customers are not included in the consolidated financial statements as they are not assets of the Company or its subsidiaries. Fee income is included as a component of noninterest income in the Consolidated Statements of Income.
Advertising Costs	Advertising Costs – All advertising costs incurred by the Company are expensed in the period in which they are incurred.
Equity Incentive Plan	Equity Incentive Plan – Compensation cost is recognized for stock options and restricted stock awards issued to employees based upon the fair value of the awards at the date of grant. A binomial model is utilized to estimate the fair value of stock options, which utilizes assumptions for expected volatilities based on the previous five-year historical volatilities of the Company's common stock. Historical data is used to estimate option exercise rates and post-vesting termination behavior, and the risk-free interest rate for the expected term of the option is based on the Treasury yield curve in effect at the time of grant. The market price of the Company’s common stock at the date of grant is used for restricted stock awards, which include restricted stock units. Compensation cost is recognized over the required service period, generally defined as the vesting period. Once the award is settled, the Company would determine whether the cumulative tax deduction exceeded the cumulative compensation cost recognized in the Consolidated Statement of Income. The cumulative tax deduction would include both the deductions from the dividends and the deduction from the exercise or vesting of the award. If the tax benefit received from the cumulative deductions exceeds the tax effect of the recognized cumulative compensation cost, the excess would be recognized as a credit to income tax expense.
Income Taxes	ncome Taxes – The Company files income tax returns in the U.S. federal jurisdiction, and in the states of Illinois, Indiana and Wisconsin. The provision for income taxes is based on income in the consolidated financial statements, rather than amounts reported on the Company’s income tax return. Income tax expense is the total of the current year income tax due or refundable and the change in deferred tax assets and liabilities. Any change in tax rates will be recorded in the period in which the law is enacted. Deferred tax assets and liabilities are recognized for the future tax consequences attributable to differences between the financial statement carrying amounts of existing assets and liabilities and their respective tax bases. Deferred tax assets and liabilities are measured using the enacted tax rates that are expected to apply to taxable income in years in which those temporary differences are expected to be recovered or settled. As of December 31, 2017 and 2016, the Company evaluated tax positions taken for filing with the Internal Revenue Service and all state jurisdictions in which it operates. The Company believes that income tax filing positions will be sustained under examination and does not anticipate any adjustments that would result in a material adverse effect on the Company’s financial condition, results of operations, or cash flows. Accordingly, the Company has not recorded any reserves or related accruals for interest and penalties for uncertain tax positions at December 31, 2017 and 2016. The Company is currently open to audit under the statute of limitations by the Internal Revenue Service from 2014 to 2016, the state of Illinois from 2014 to 2016, and the states of Wisconsin and Indiana from 2009 to 2016.
Earnings Per Common Share ("EPS")	Earnings Per Common Share (“EPS”) – Basic EPS is computed by dividing net income applicable to common stockholders by the weighted-average number of common shares outstanding for the period. Diluted EPS is computed by dividing net income applicable to common stockholders by the weighted-average number of common shares outstanding plus the number of additional common shares that would have been outstanding if the dilutive potential shares had been issued. The Company’s potential common shares represent shares issuable under its long-term incentive compensation plans and under the common stock warrant issued to preferred stockholders. Such common stock equivalents are computed based on the treasury stock method using the average market price for the period.
Treasury Stock	Treasury Stock – Treasury stock acquired is recorded at cost and is carried as a reduction of stockholders’ equity in the Consolidated Balance Sheet. Treasury stock issued is valued based on the “last in, first out” inventory method. The difference between the consideration received upon issuance and the carrying value is charged or credited to additional paid-in capital.
Derivative Financial Instruments	Derivative Financial Instruments – The Company occasionally enters into derivative financial instruments as part of its interest rate risk management strategies. These derivative financial instruments consist primarily of interest rate swaps; in addition, three risk participation agreements were held by the Company as of December 31, 2017, and one was held as of December 31, 2016. All risk participation agreements are recorded at fair value and are immaterial. The Company records all derivatives on the balance sheet at fair value. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative and whether the Company has elected to designate a derivative as a hedging relationship and apply hedge accounting. A further consideration involves a determination on whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. Derivatives designated and qualifying as a hedge of the exposure to changes in the fair value of an asset, liability, or firm commitment attributable to a particular risk, such as interest rate risk, are considered fair value hedges. Hedge accounting generally provides for the matching of the timing of gain or loss recognition on the hedging instrument with the recognition of the changes in the fair value of the hedged asset or liability that are attributable to the hedged risk in a fair value hedge or the earnings effect of the hedged forecasted transactions in a cash flow hedge. The Company may enter into derivative contracts that are intended to economically hedge certain risks, even though hedge accounting does not apply or the Company elects not to apply hedge accounting. If it is determined that the derivative instrument is not highly effective as a hedge, hedge accounting is discontinued, and the adjustment to fair value of the derivative instrument is recorded in earnings. For a derivative used to hedge changes in cash flows associated with forecasted transactions, the gain or loss on the effective portion of the derivative are deferred and reported as a component of accumulated other comprehensive income, which is a component of stockholders’ equity, until such time the hedged transaction affects earnings. For derivative instruments not accounted for as hedges, changes in fair value are recognized in noninterest income/expense. Counterparty risk with correspondent banks is considered through loan covenant agreements and, as such, does not have a significant impact on the fair value of the swaps. Deferred gains and losses from derivatives not accounted for as hedges and that are terminated are amortized over the shorter of the original remaining term of the derivative or the remaining life of the underlying asset or liability.
Comprehensive Income (Loss)	Comprehensive Income – Comprehensive income is the total of reported earnings for all other revenues, expenses, gains, and losses that are not reported in earnings under GAAP. The Company includes the following items, net of tax, in other comprehensive income in the Consolidated Statements of Comprehensive Income: (i) changes in unrealized gains or losses on securities available-for-sale, (ii) changes in unrealized gains or losses on securities held-to-maturity established upon transfer from securities available-for-sale and (iii) the effective portion of a derivative used to hedge cash flows. Accumulated other comprehensive income (loss) at December 31, 2017 and 2016, is comprised of unrealized gains on securities of $2.2 million and unrealized losses on securities of $8.2 million, respectively, and unrealized losses on a cash flow hedge of $760,000 and $596,000, respectively.
New Accounting Pronouncements	Recent Accounting Pronouncements – The following is a summary of recent accounting pronouncements that have impacted or could potentially affect the Company : In May 2014, the FASB issued ASU No. 2014-09 "Revenue from Contracts with Customers (Topic 606)." The core principle of the guidance is that an entity should recognize revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods and services. In August 2015, the FASB issued ASU 2015-14 “ Revenue from Contracts with Customers (Topic 606) Deferral of the Effective Date .” This accounting standards update defers the effective date of ASU 2014-09 for an additional year. ASU 2015-14 will be effective for annual reporting periods beginning after December 15, 2017. The amendments can be applied retrospectively to each prior reporting period or retrospectively with the cumulative effect of initially applying this update recognized at the date of initial application. Early application is not permitted. In March 2016, the FASB issued ASU 2016-08 “ Revenue from Contracts with Customers (TOPIC 606): Principal versus Agent Considerations (Reporting Revenue Gross versus Net) ” and in April 2016, the FASB issued ASU 2016-10 “ Revenue from Contracts with Customers (TOPIC 606): Identifying Performance Obligations and Licensing.” ASU 2016-08 requires the entity to determine if it is acting as a principal with control over the goods or services it is contractually obligated to provide, or an agent with no control over specified goods or services provided by another party to a customer. ASU 2016-10 was issued to further clarify ASU 2014-09 implementation regarding identifying performance obligation materiality, identification of key contract components, and scope. The Company is assessing the impact of ASU 2014-09 and other related ASUs as noted above on its accounting and disclosures within noninterest income, as any interest income impact was scoped out of this final ASU pronouncement. The Company will adopt ASU 2014-09 and related issuances on January 1, 2018. The Company has performed an analysis of the impact of adoption of this ASU, reviewing revenue recorded from service charges on deposit accounts, asset management fees, gains (losses) on other real estate owned, and debit card interchange fees. Certain revenue received, such as service charges on deposit accounts and interchange fees, is recorded immediately or as the service is performed. Asset management fees recorded by the Company take the form of wealth management income and brokerage income, and both types of fees are recorded after services are rendered, with no contractual requirement of refund to a customer based on non-achievement of fund performance objectives. Finally, the methodology used to record revenue from gains (losses) due to the sale of other real estate owned is not anticipated to change, as the Company currently records income or expense only upon consummation of the sale, and any revenue recorded stemming from seller financed transactions is reviewed for deferral, as appropriate. The Company does not expect to recognize a cumulative adjustment to equity upon implementation of this standard. In February 2016, the FASB issued ASU No. 2016-02 “ Leases (Topic 842) .” This ASU was issued to increase transparency and comparability among organizations by recognizing lease assets and liabilities on the balance sheet and disclosing key information about leasing arrangements. One key revision from prior guidance was to include operating leases within assets and liabilities recorded; another revision was included which created a new model to follow for sale-leaseback transactions. The impact of this pronouncement will affect lessees primarily, as virtually all of their assets will be recognized on the balance sheet, by recording a right of use asset and lease liability. This pronouncement is effective for fiscal years beginning after December 15, 2018. The Company is assessing the impact of ASU 2016-02 on its accounting and disclosures. In March 2016, the FASB issued ASU No. 2016-09 “ Stock Compensation - Improvements to Employee Share-Based Payment Accounting (Topic 718). ” FASB issued this ASU as part of the Simplification Initiative. This ASU involves several aspects of the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liability, and classification on the statement of cash flows. ASU 2016-09 was effective for financial statements issued for fiscal years beginning after December 15, 2016. The Company adopted this standard as of January 1, 2017, which impacted income tax expense and additional paid-in capital within stockholders’ equity, but did not have a material impact on the Company’s operating results or financial condition. In June 2016, the FASB issued ASU No. 2016-13 “ Measurement of Credit Losses on Financial Instruments (Topic 326). ” ASU 2016-13 was issued to provide financial statement users with more useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date to enhance the decision making process. The new methodology to be used should reflect expected credit losses based on relevant vintage historical information, supported by reasonable forecasts of projected loss given defaults, that will affect the collectability of the reported amounts. This new methodology will also require available-for-sale debt securities to have a credit loss recorded through an allowance rather than write-downs. ASU 2016-13 is effective for financial statements issued for fiscal years beginning after December 15, 2019. The Company is assessing the impact of ASU 2016-13 on its accounting and disclosures, and is in the process of accumulating data to support future risk assessments. In January 2017, the FASB issued ASU 2017-04 “ Intangibles – Goodwill and Other (Topic 350) .” The FASB issued this guidance to simplify the annual test for goodwill impairment by eliminating Step 2 from the prior two step guidance. Previous guidance required the quantitative measurement of an entity’s goodwill impairment loss by comparing the implied fair value of a reporting unit’s goodwill with the carrying amount of that goodwill. The amended guidance allows a more qualitative analysis of comparing the reporting unit’s fair value to its carrying value, and recording the resultant impairment charge, not to exceed the total amount of goodwill allocated to that reporting unit, if applicable. ASU 2017-04 is effective for financial statements issued for fiscal years beginning after December 15, 2019, with early adoption permitted for annual and interim goodwill impairment tests after January 1, 2017. The Company adopted this ASU as of December 31, 2017, and applied the new guidance to the annual goodwill impairment test performed as of that date; no impairment was noted. In March 2017, the FASB issued ASU No. 2017-08 “ Receivables-Nonrefundable Fees and Other Costs – Premium Amortization on Purchased Callable Debt Securities (Subtopic 310-20) .” This ASU was issued to shorten the amortization period for the premium to the earliest call date on debt securities. This premium is required to be recorded as a reduction to net interest margin during the shorter yield to call period, as compared to prior practice of amortizing the premium as a reduction to net interest margin over the contractual life of the instrument. This ASU does not change the current method of amortizing any discount over the contractual life of the debt security, and this pronouncement is effective for fiscal years beginning after December 15, 2018, with earlier adoption permitted. The Company adopted ASU 2017-08 as a change in accounting principle in the third quarter of 2017 on a modified retrospective basis, which required the Company to reflect its adoption effective January 1, 2017. The effect of amortizing the premium over a shorter period negatively impacted the net interest margin in 2017, and will continue to decrease future net interest income by approximately 10 basis points a quarter until the premium is fully amortized. As a result of management’s analysis, the impact of the change in accounting principle as a result of ASU 2017-08 to adjust beginning of year retained earnings was considered insignificant and, accordingly, the impact was adjusted through current period earnings. In August 2017, the FASB issued ASU 2017-12 “ Derivatives and Hedging: Targeted Improvements to Accounting for Hedging Activities.”. The purpose of this updated guidance is to better align a company’s financial reporting for hedging activities with the economic objectives of those activities. ASU 2017-12 is effective for public business entities for fiscal years beginning after December 15, 2018, with early adoption, including adoption in an interim period, permitted. The Company plans to adopt ASU 2017-12 on January 1, 2018. ASU 2017-12 requires a modified retrospective transition method in which the Company will recognize the cumulative effect of the change on the opening balance of each affected component of equity in the statement of financial position as of the date of adoption. While the Company continues to assess all potential impacts of the standard, we currently expect adoption to have an immaterial impact on our consolidated financial statements. In February 2018, the FASB issued ASU 2018-02 “ Income Statement-Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income ”. This ASU provides financial statement preparers an option to reclassify stranded tax effects within AOCI to retained earnings, which were recorded due to the change in the U.S. Federal corporate income tax rate in the “Tax Cuts and Jobs Act”, signed into law in December 2017. ASU 2018-02 is effective for fiscal years beginning after December 15, 2018, and interim periods within those fiscal years. Early adoption is permitted. The Company plans to adopt ASU 2018-02 on January 1, 2018. The estimated stranded disproportionate tax expense, net, recorded as of December 31, 2017, totaled $318,000, and was comprised of both swap and securities available for sale adjustments.
Subsequent Events	Subsequent Events On January 16, 2018, the Company’s Board of Directors declared a cash dividend of $0.01 per share payable on February 5, 2018, to stockholders of record as of January 26, 2018. On February 20, 2018, the Company’s board of directors determined not to renew the Second Amendment to the Amended and Restated Rights Agreement and Tax Benefits Preservation Plan (the “Amendment”), dated September 2, 2015, that was approved by the Company’s stockholders, which expires on September 12, 2018. The Amendment was approved in 2015 to protect the Company’s ability to utilize deferred tax assets, which could be significantly limited if it experienced an “ownership change” for U.S. federal income tax purposes.
Mortgage Banking Derivatives
Summary of Significant Accounting Policies
Derivative Financial Instruments	Mortgage Banking Derivatives – As part of the ongoing residential mortgage business, the Company enters into mortgage banking derivatives such as forward contracts and interest rate lock commitments. The derivatives and loans held-for-sale are carried at fair value with the changes in fair value recorded in current earnings. The net gain or loss on mortgage banking derivatives is included in net gains on sales of loans in the Consolidated Statements of Income .
Commercial
Summary of Significant Accounting Policies
Loans	Commercial Loans – Such credits typically comprise working capital loans, loans for physical asset expansion, asset acquisition loans and other commercial and industrial business loans. Loans to closely held businesses will generally be guaranteed in full or for a meaningful amount by the businesses’ major owners. Commercial loans are made based primarily on the historical and projected cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not behave as forecasted and collateral securing loans may fluctuate in value due to economic or individual performance factors. Minimum standards and underwriting guidelines have been established for all commercial loan types.
Real estate - commercial
Summary of Significant Accounting Policies
Loans	Lease Financing Receivables – Lease financing receivables are subject to underwriting standards and processes similar to commercial loans. These loans are often secured by equipment or transportation assets, and are made based primarily on the historical and projected cash flow of the borrower and secondarily on the underlying collateral provided by the borrower. The cash flows of borrowers, however, may not behave as forecasted and collateral securing loans may fluctuate in value due to economic or individual performance factors. Real Estate - Commercial Loans – Real estate - commercial loans are subject to underwriting standards and processes similar to commercial and industrial loans. These are loans secured by mortgages on real estate collateral. Commercial real estate loans are viewed primarily as cash flow loans and the repayment of these loans is largely dependent on the successful operation of the property. Loan performance may be adversely affected by factors impacting the general economy or conditions specific to the real estate market such as geographic location and/or property type.
Real estate - residential
Summary of Significant Accounting Policies
Loans	Real Estate - Residential Loans – These are loans that are extended to purchase or refinance 1-4 family residential dwellings, or to purchase or refinance vacant lots intended for the construction of a 1-4 family home. Residential real estate loans are considered homogenous in nature. Homes may be the primary or secondary residence of the borrower or may be investment properties of the borrower.
Consumer
Summary of Significant Accounting Policies
Loans	Consumer Loans – Consumer loans include loans extended primarily for consumer and household purposes. These also include overdrafts and other items not captured by the definitions above.
Construction Loans | Real estate - commercial
Summary of Significant Accounting Policies
Loans	Real Estate - Construction Loans – The Company defines real estate - construction loans as loans where the loan proceeds are controlled by the Company and used exclusively for the improvement or development of real estate in which the Company holds a mortgage. Due to the inherent risk in this type of loan, they are subject to other industry specific policy guidelines outlined in the Company’s Credit Risk Policy and are monitored closely.

Acquisitions (Tables)

Acquisitions (Tables)	12 Months Ended
	Dec. 31, 2017
Talmer
Business Acquisition [Line Items]
Talmer Branch Acquisition Summary	Talmer Branch Acquisition Summary As of Date of Acquisition 10/28/2016 Assets acquired: Cash on hand $ 122 Loans, net of purchase accounting adjustments 220,988 Premises and equipment, net 230 Goodwill 8,375 Core deposit intangible 659 Other assets acquired, including accrued interest, prepaids 573 Liabilities assumed: Deposits - noninterest bearing demand 28,850 Deposits - interest bearing - Savings, NOW and Money market 17,941 Deposits - Time 2,103 Other liabilities assumed, including escrow deposits and payables 574 Net assets acquired, or total cash paid for acquisition $

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2017
Securities
Schedule of amortized cost and fair value of the securities portfolio and corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive loss	Gross Gross Amortized Unrealized Unrealized Fair December 31, 2017 Cost Gains Losses Value Securities available-for-sale U.S. Treasuries $ 4,002 $ - $ (55) $ 3,947 U.S. government agencies 13,062 8 (9) 13,061 U.S. government agencies mortgage-backed 12,372 7 (165) 12,214 States and political subdivisions 272,240 7,116 (1,264) 278,092 Corporate bonds 823 21 (11) 833 Collateralized mortgage obligations 66,892 202 (1,155) 65,939 Asset-backed securities 113,983 862 (1,913) 112,932 Collateralized loan obligations 54,271 251 (101) 54,421 Total securities available-for-sale $ 537,645 $ 8,467 $ (4,673) $ 541,439 Gross Gross Amortized Unrealized Unrealized Fair December 31, 2016 Cost Gains Losses Value Securities available-for-sale U.S. government agencies mortgage-backed $ 42,511 $ - $ (977) $ 41,534 States and political subdivisions 68,718 258 (273) 68,703 Corporate bonds 10,957 9 (336) 10,630 Collateralized mortgage obligations 174,352 374 (3,799) 170,927 Asset-backed securities 146,391 341 (8,325) 138,407 Collateralized loan obligations 102,504 29 (896) 101,637 Total securities available-for-sale $ 545,433 $ 1,011 $ (14,606) $ 531,838
Schedule of fair value, amortized cost and weighted average yield of debt securities by contractual maturity along with securities not due at a single maturity date, primarily mortgage-backed securities (MBS), asset-backed securities, and collateralized loan obligations	Weighted Amortized Average Fair Securities available-for-sale Cost Yield Value Due in one year or less $ 6,200 2.41 % $ 6,185 Due after one year through five years 4,346 2.03 4,279 Due after five years through ten years 6,013 3.29 6,234 Due after ten years 273,568 2.95 279,235 290,127 2.93 295,933 Mortgage-backed and collateralized mortgage obligations 79,264 2.94 78,153 Asset-backed securities 113,983 2.56 112,932 Collateralized loan obligations 54,271 4.32 54,421 Total securities available-for-sale $ 537,645 2.99 % $ 541,439
Schedule of securities with unrealized losses aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position	Less than 12 months 12 months or more December 31, 2017 in an unrealized loss position in an unrealized loss position Total Number of Unrealized Fair Number of Unrealized Fair Number of Unrealized Fair Securities available-for-sale Securities Losses Value Securities Losses Value Securities Losses Value U.S. Treasuries 1 $ 55 $ 3,947 - $ - $ - 1 $ 55 $ 3,947 U.S. government agencies 2 9 6,550 - - - 2 9 6,550 U.S. government agencies mortgage-backed 4 24 5,501 5 141 4,843 9 165 10,344 States and political subdivisions 13 1,237 45,985 1 27 1,512 14 1,264 47,497 Corporate bonds - - - 1 11 332 1 11 332 Collateralized mortgage obligations 3 31 11,534 8 1,124 40,219 11 1,155 51,753 Asset-backed securities - - - 7 1,913 61,745 7 1,913 61,745 Collateralized loan obligations 3 101 29,313 - - - 3 101 29,313 Total securities available-for-sale 26 $ 1,457 $ 102,830 22 $ 3,216 $ 108,651 48 $ 4,673 $ 211,481 Less than 12 months 12 months or more December 31, 2016 in an unrealized loss position in an unrealized loss position Total Number of Unrealized Fair Number of Unrealized Fair Number of Unrealized Fair Securities available-for-sale Securities Losses Value Securities Losses Value Securities Losses Value U.S. government agencies mortgage-backed 11 $ 957 $ 40,636 1 $ 20 $ 898 12 $ 977 $ 41,534 States and political subdivisions 12 273 35,241 - - - 12 273 35,241 Corporate bonds 1 183 4,817 2 153 5,328 3 336 10,145 Collateralized mortgage obligations 16 3,402 117,752 7 397 18,109 23 3,799 135,861 Asset-backed securities 4 328 17,604 12 7,997 107,112 16 8,325 124,716 Collateralized loan obligations - - - 12 896 81,613 12 896 81,613 Total securities available-for-sale 44 $ 5,143 $ 216,050 34 $ 9,463 $ 213,060 78 $ 14,606 $ 429,110
Schedule of proceeds from sale and gross realized gains and losses on sale of securities	Years ended December 31, Securities available-for-sale 2017 2016 2015 Proceeds from sales of securities $ 232,462 $ 306,400 $ 70,176 Gross realized gains on securities 2,367 1,675 106 Gross realized losses on securities (1,893) (3,888) (284) Securities realized gains (losses), net $ 474 $ (2,213) $ (178) Income tax expense (benefit) on net realized gains (losses) $ 198 $ (882) $ (71)

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2017
Loans
Schedule of major classifications of loans	December 31, 2017 December 31, 2016 Commercial $ 272,851 $ 228,113 Leases 68,325 55,451 Real estate - commercial 750,991 736,247 Real estate - construction 85,162 64,720 Real estate - residential 426,230 377,851 Consumer 2,774 3,237 Other 1 10,609 11,973 1,616,942 1,477,592 Net deferred loan costs 680 1,217 Total loans $ 1,617,622 $ 1,478,809
Schedule of aged analysis of past due loans by class of loans	Aged analysis of past due loans by class of loans as of December 31, 2017, and December 31, 2016, were as follows: Recorded Investment 90 days or 90 Days or Greater Past 30-59 Days 60-89 Days Greater Past Total Past Due and December 31, 2017 Past Due Past Due Due Due Current Nonaccrual Total Loans Accruing Commercial $ 995 $ 275 $ - $ 1,270 $ 271,581 $ - $ 272,851 $ - Leases - - - - 68,147 178 68,325 - Real estate - commercial Owner occupied general purpose 1,136 - - 1,136 144,267 455 145,858 - Owner occupied special purpose 226 - - 226 170,546 342 171,114 - Non-owner occupied general purpose - 593 - 593 273,203 1,163 274,959 - Non-owner occupied special purpose - - 248 248 92,923 - 93,171 254 Retail properties - - - - 49,538 1,081 50,619 - Farm - - - - 15,270 - 15,270 - Real estate - construction Homebuilder 129 - - 129 2,221 - 2,350 - Land 1,124 - - 1,124 1,319 - 2,443 - Commercial speculative - - - - 32,028 - 32,028 - All other - - - - 48,140 201 48,341 - Real estate - residential Investor - - - - 55,248 372 55,620 - Multifamily - - - - 125,049 4,723 129,772 - Owner occupied 74 - - 74 123,838 4,674 128,586 - Revolving and junior liens 491 278 - 769 110,291 1,192 112,252 - Consumer - - - - 2,767 7 2,774 - Other 1 37 - - 37 11,252 - 11,289 - Total $ 4,212 $ 1,146 $ 248 $ 5,606 $ 1,597,628 $ 14,388 $ 1,617,622 $ 254 Recorded Investment 90 days or 90 Days or Greater Past 30-59 Days 60-89 Days Greater Past Total Past Due and December 31, 2016 Past Due Past Due Due Due Current Nonaccrual Total Loans Accruing Commercial $ 57 $ 74 $ - $ 131 $ 227,742 $ 240 $ 228,113 $ - Leases - 286 - 286 54,799 366 55,451 - Real estate - commercial Owner occupied general purpose 758 - - 758 135,599 879 137,236 - Owner occupied special purpose - - - - 177,755 385 178,140 - Non-owner occupied general purpose 667 379 - 1,046 229,315 1,930 232,291 - Non-owner occupied special purpose - - - - 118,052 1,013 119,065 - Retail properties - - - - 53,474 1,179 54,653 - Farm 1,353 - - 1,353 13,509 - 14,862 - Real estate - construction Homebuilder - - - - 3,883 - 3,883 - Land - - - - 3,029 - 3,029 - Commercial speculative - - - - 22,654 74 22,728 - All other 364 - - 364 34,509 207 35,080 - Real estate - residential Investor 237 - - 237 54,924 936 56,097 - Multifamily - - - - 96,502 - 96,502 - Owner occupied 274 - - 274 116,900 6,452 123,626 - Revolving and junior liens 225 405 - 630 99,374 1,622 101,626 - Consumer 10 36 - 46 3,191 - 3,237 - Other 1 14 - - 14 13,176 - 13,190 - Total $ 3,959 $ 1,180 $ - $ 5,139 $ 1,458,387 $ 15,283 $ 1,478,809 $ - 1 The “Other” class includes overdrafts and net deferred costs.
Schedule of credit quality indicators by class of loans	December 31, 2017 Special Pass Mention Substandard 1 Doubtful Total Commercial $ 270,889 $ 1,962 $ - $ - $ 272,851 Leases 67,500 - 825 - 68,325 Real estate - commercial Owner occupied general purpose 142,843 1,927 1,088 - 145,858 Owner occupied special purpose 169,621 1,152 341 - 171,114 Non-owner occupied general purpose 271,731 2,065 1,163 - 274,959 Non-owner occupied special purpose 89,582 - 3,589 - 93,171 Retail Properties 48,321 1,217 1,081 - 50,619 Farm 11,755 1,029 2,486 - 15,270 Real estate - construction Homebuilder 2,350 - - - 2,350 Land 2,443 - - - 2,443 Commercial speculative 32,028 - - - 32,028 All other 46,913 1,052 376 - 48,341 Real estate - residential Investor 55,172 - 448 - 55,620 Multifamily 125,049 - 4,723 - 129,772 Owner occupied 122,759 561 5,266 - 128,586 Revolving and junior liens 110,353 - 1,899 - 112,252 Consumer 2,754 - 20 - 2,774 Other 11,289 - - - 11,289 Total $ 1,583,352 $ 10,965 $ 23,305 $ - $ 1,617,622 December 31, 2016 Special Pass Mention Substandard 1 Doubtful Total Commercial $ 214,028 $ 11,558 $ 2,527 $ - $ 228,113 Leases 53,366 976 1,109 - 55,451 Real estate - commercial Owner occupied general purpose 135,503 53 1,680 - 137,236 Owner occupied special purpose 172,353 5,402 385 - 178,140 Non-owner occupied general purpose 229,448 913 1,930 - 232,291 Non-owner occupied special purpose 114,293 - 4,772 - 119,065 Retail Properties 52,207 1,267 1,179 - 54,653 Farm 11,840 1,240 1,782 - 14,862 Real estate - construction Homebuilder 3,883 - - - 3,883 Land 3,029 - - - 3,029 Commercial speculative 22,654 - 74 - 22,728 All other 34,696 - 384 - 35,080 Real estate - residential Investor 55,001 - 1,096 - 56,097 Multifamily 96,502 - - - 96,502 Owner occupied 115,831 570 7,225 - 123,626 Revolving and junior liens 99,286 - 2,340 - 101,626 Consumer 3,236 - 1 - 3,237 Other 13,165 25 - - 13,190 Total $ 1,430,321 $ 22,004 $ 26,484 $ - $ 1,478,809 1 The substandard credit quality indicator includes both potential problem loans that are currently performing and nonperforming loans.
Schedule of impaired loans by class of loan	December 31, 2017 December 31, 2016 Unpaid Unpaid Recorded Principal Related Recorded Principal Related Investment Balance Allowance Investment Balance Allowance With no related allowance recorded Commercial $ - $ - $ - $ 240 $ 388 $ - Leases 178 213 - 366 371 - Commercial real estate Owner occupied general purpose 455 495 - 1,881 2,131 - Owner occupied special purpose 342 498 - 385 518 - Non-owner occupied general purpose 1,163 1,538 - 1,744 2,010 - Non-owner occupied special purpose - - - 1,013 1,649 - Retail properties 1,081 1,177 - 1,179 1,235 - Farm - - - - - - Construction Homebuilder - - - - - - Land - - - - - - Commercial speculative - - - 74 81 - All other 201 229 - 207 221 - Residential Investor 372 676 - 1,841 2,308 - Multifamily 4,723 4,965 - - - - Owner occupied 5,208 6,680 - 9,824 11,391 - Revolving and junior liens 1,125 1,313 - 2,484 3,018 - Consumer 7 8 - - - - Total impaired loans with no recorded allowance 14,855 17,792 - 21,238 25,321 - With an allowance recorded Commercial - - - - - - Leases - - - - - - Commercial real estate Owner occupied general purpose - - - - - - Owner occupied special purpose - - - - - - Non-owner occupied general purpose - - - 246 595 246 Non-owner occupied special purpose - - - - - - Retail properties - - - - - - Farm - - - - - - Construction Homebuilder - - - - - - Land - - - - - - Commercial speculative - - - - - - All other - - - - - - Residential Investor 829 829 10 - - - Multifamily - - - - - - Owner occupied 3,443 3,443 43 803 853 803 Revolving and junior liens 985 985 91 - - - Consumer - - - - - - Total impaired loans with a recorded allowance 5,257 5,257 144 1,049 1,448 1,049 Total impaired loans $ 20,112 $ 23,049 $ 144 $ 22,287 $ 26,769 $ 1,049 Average recorded investment and interest income recognized on impaired loans by class of loan for the years ending December 31 were as follows: Year to date Year to date Year to date December 31, 2017 December 31, 2016 December 31, 2015 Average Interest Average Interest Average Interest Recorded Income Recorded Income Recorded Income Investment Recognized Investment Recognized Investment Recognized With no related allowance recorded Commercial $ 120 $ - $ 155 $ - $ 785 $ - Lease 272 - 183 - - - Commercial real estate Owner occupied general purpose 1,168 - 2,098 87 4,720 82 Owner occupied special purpose 364 - 574 - 1,280 - Non-owner occupied general purpose 1,453 - 1,395 2 2,939 3 Non-owner occupied special purpose 507 - 507 - 712 - Retail properties 1,130 - 589 - - - Farm - - 636 - 636 - Construction Homebuilder - - - - 895 - Land - - - - - - Commercial speculative 37 - 79 - 42 - All other 204 - 103 - 145 - Residential Investor 1,106 - 1,874 47 2,251 51 Multifamily 2,362 - - - - - Owner occupied 7,516 44 10,181 158 10,979 160 Revolving and junior liens 1,804 1 2,608 29 2,484 7 Consumer 4 - - - - - Total impaired loans with no recorded allowance 18,047 45 20,982 323 27,868 303 With an allowance recorded Commercial - - 2 - 2 - Leases - - - - - - Commercial real estate Owner occupied general purpose - - - - - - Owner occupied special purpose - - - - - - Non-owner occupied general purpose 123 - 123 - 38 - Non-owner occupied special purpose - - - - - - Retail properties - - - - - - Farm - - - - - - Construction Homebuilder - - - - - - Land - - - - - - Commercial speculative - - - - - - All other - - - - 135 - Residential Investor 414 43 - - 67 - Multifamily - - - - - - Owner occupied 2,123 123 457 - 68 - Revolving and junior liens 493 35 23 - 208 3 Consumer - - - - - - Total impaired loans with a recorded allowance 3,153 201 605 - 518 3 Total impaired loans $ 21,200 $ 246 $ 21,587 $ 323 $ 28,386 $ 306
Schedule of TDRs modified during the period by type of modification	Loans that were modified during the period are summarized as follows: TDR Modifications Twelve months ended December 31, 2017 # of Pre-modification Post-modification contracts recorded investment recorded investment Troubled debt restructurings Real estate - commercial Other 1 1 $ 97 $ 131 Real estate - residential Owner occupied HAMP 2 2 184 189 Other 1 1 41 42 Revolving and junior liens HAMP 2 1 49 49 Other 1 6 319 350 Total 11 $ 690 $ 761 TDR Modifications Twelve months ended December 31, 2016 # of Pre-modification Post-modification contracts recorded investment recorded investment Troubled debt restructurings Real estate - commercial Other 1 2 $ 312 $ 205 Real estate - residential Owner occupied HAMP 2 2 419 262 Revolving and junior liens HAMP 2 3 252 228 Other 1 3 808 777 Total 10 $ 1,791 $ 1,472 1 Other: Change of terms from bankruptcy court 2 HAMP: Home Affordable Modification Program
Schedule of loans to principal officers, directors, and their affiliates, made in the ordinary course of business	2017 2016 Beginning balance $ 1,703 $ 1,787 New loans 20 157 Repayments and other reductions (199) (241) Change in related party status - - Ending balance $ 1,524 $ 1,703

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2017
Allowance for Loan Losses
Schedule of changes in the allowance for loan losses by segment of loans based on method of impairment	Changes in the ALLL by segment of loans based on method of impairment for the year ended December 31, 2017, were as follows: Real Estate Real Estate Real Estate Allowance for loan and lease losses: Commercial Leases Commercial Construction Residential Consumer Other Total Beginning balance $ 1,629 $ 633 $ 9,547 $ 389 $ 2,692 $ 833 $ 435 $ 16,158 Charge-offs 25 215 309 23 1,347 386 1 2,306 Recoveries 30 - 161 377 980 243 18 1,809 Provision (Release) 819 274 123 180 (520) 834 90 1,800 Ending balance $ 2,453 $ 692 $ 9,522 $ 923 $ 1,805 $ 1,524 $ 542 $ 17,461 Ending balance: Individually evaluated for impairment $ - $ - $ - $ - $ 53 $ 91 $ - $ 144 Ending balance: Collectively evaluated for impairment $ 2,453 $ 692 $ 9,522 $ 923 $ 1,752 $ 1,433 $ 542 $ 17,317 Loans: Ending balance $ 272,851 $ 68,325 $ 750,991 $ 85,162 $ 426,230 $ 2,774 $ 11,289 $ 1,617,622 Ending balance: Individually evaluated for impairment $ - $ 178 $ 3,041 $ 201 $ 14,575 $ 2,117 $ - $ 20,112 Ending balance: Collectively evaluated for impairment $ 272,851 $ 68,147 $ 747,950 $ 84,961 $ 411,655 $ 657 $ 11,289 $ 1,597,510 Changes in the ALLL by segment of loans based on method of impairment for December 31, 2016, were as follows: Real Estate Real Estate Real Estate Allowance for loan and lease losses: Commercial Leases Commercial Construction Residential Consumer Other Total Beginning balance $ 1,463 $ 633 $ 9,013 $ 265 $ 1,694 $ 1,190 $ 1,965 $ 16,223 Charge-offs 95 23 1,633 23 1,072 344 - 3,190 Recoveries 32 5 640 96 1,331 253 18 2,375 Provision (Release) 229 18 1,527 51 739 (266) (1,548) 750 Ending balance $ 1,629 $ 633 $ 9,547 $ 389 $ 2,692 $ 833 $ 435 $ 16,158 Ending balance: Individually evaluated for impairment $ - $ - $ 246 $ - $ 803 $ - $ - $ 1,049 Ending balance: Collectively evaluated for impairment $ 1,629 $ 633 $ 9,301 $ 389 $ 1,889 $ 833 $ 435 $ 15,109 Loans: Ending balance $ 228,113 $ 55,451 $ 736,247 $ 64,720 $ 377,851 $ 3,237 $ 13,190 $ 1,478,809 Ending balance: Individually evaluated for impairment $ 240 $ 366 $ 6,448 $ 281 $ 14,952 $ - $ - $ 22,287 Ending balance: Collectively evaluated for impairment $ 227,873 $ 55,085 $ 729,799 $ 64,439 $ 362,899 $ 3,237 $ 13,190 $ 1,456,522 Changes in the ALLL by segment of loans based on method of impairment for the year ended December 31, 2015, were as follows: Commercial Real Estate Real Estate Real Estate Allowance for loan and lease losses: & Leases Commercial Construction Residential Consumer Other Total Beginning balance $ 1,644 $ 12,577 $ 1,475 $ 1,981 $ 1,454 $ 2,506 $ 21,637 Charge-offs 993 1,653 2 1,639 483 - 4,770 Recoveries 451 1,595 276 1,075 359 - 3,756 Provision (Release) 994 (3,506) (1,484) 277 (140) (541) (4,400) Ending balance $ 2,096 $ 9,013 $ 265 $ 1,694 $ 1,190 $ 1,965 $ 16,223 Ending balance: Individually evaluated for impairment $ 3 $ - $ - $ 31 $ - $ - $ 34 Ending balance: Collectively evaluated for impairment $ 2,093 $ 9,013 $ 265 $ 1,663 $ 1,190 $ 1,965 $ 16,189 Loans: Ending balance $ 141,315 $ 605,721 $ 19,806 $ 351,007 $ 4,216 $ 11,650 $ 1,133,715 Ending balance: Individually evaluated for impairment $ 73 $ 5,396 $ 83 $ 15,334 $ - $ - $ 20,886 Ending balance: Collectively evaluated for impairment $ 141,242 $ 600,325 $ 19,723 $ 335,673 $ 4,216 $ 11,650 $ 1,112,829

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	12 Months Ended
	Dec. 31, 2017
Other Real Estate Owned
Schedule of activity in the other real estate owned (OREO) portfolio, net of valuation reserve	Twelve Months Ended December 31, Other real estate owned 2017 2016 2015 Balance at beginning of period $ 11,916 $ 19,141 $ 31,982 Property additions 3,796 1,785 8,998 Property improvements - 16 - Less: Proceeds from property disposals, net of participation purchase and of gains/losses 5,633 7,456 17,763 Period valuation adjustments 1,708 1,570 4,076 Balance at end of period $ 8,371 $ 11,916 $ 19,141
Schedule of activity in valuation allowance	Twelve Months Ended December 31, 2017 2016 2015 Balance at beginning of period $ 9,982 $ 14,127 $ 19,229 Provision for unrealized losses 1,708 1,570 4,076 Reductions taken on sales (3,482) (5,867) (9,271) Other adjustments - 152 93 Balance at end of period $ 8,208 $ 9,982 $ 14,127
Schedule of expenses related to foreclosed assets, net of lease revenue	Twelve Months Ended December 31, 2017 2016 2015 Gain on sales, net $ (474) $ (374) $ (1,073) Provision for unrealized losses 1,708 1,570 4,076 Operating expenses 1,227 1,765 2,888 Less: Lease revenue 296 218 700 Net OREO expense $ 2,165 $ 2,743 $ 5,191

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2017
Premises and Equipment
Schedule of components of premises and equipment	2017 2016 Accumulated Accumulated Depreciation/ Net Book Depreciation/ Net Book Cost Amortization Value Cost Amortization Value Land $ 16,124 $ - $ 16,124 $ 16,141 $ - $ 16,141 Buildings 41,499 22,935 18,564 41,409 21,966 19,443 Leasehold improvements 156 144 12 156 86 70 Furniture and equipment 42,910 39,982 2,928 42,875 39,552 3,323 Total Premises and Equipment $ 100,689 $ 63,061 $ 37,628 $ 100,581 $ 61,604 $ 38,977

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2017
Deposits
Schedule of major classifications of deposits	2017 2016 Noninterest bearing demand $ 572,404 $ 513,688 Savings 262,220 256,159 NOW accounts 429,448 419,417 Money market accounts 276,082 275,273 Certificates of deposit of less than $100,000 216,493 228,993 Certificates of deposit of $100,000 through $250,000 122,489 110,992 Certificates of deposit of more than $250,000 43,789 62,263 Total deposits $ 1,922,925 $ 1,866,785
Summary of scheduled maturities of time deposits	2018 $ 158,547 2019 101,609 2020 84,951 2021 32,271 2022 5,393 Total time deposits $ 382,771

Borrowings (Tables)

Borrowings (Tables)	12 Months Ended
	Dec. 31, 2017
Borrowings
Summary of borrowings and junior subordinated debentures	2017 2016 Securities sold under repurchase agreements $ 29,918 $ 25,715 FHLBC advances 1 115,000 70,000 Junior subordinated debentures 57,639 57,591 Senior notes 44,058 43,998 Total borrowings $ 246,615 $ 197,304
Summary of scheduled maturities and weighted average rates of borrowings	2017 2016 Weighted Weighted Average Average Balance Rate Balance Rate 2017 N/A N/A $ 95,715 0.51 % 2018 $ 144,918 0.86 % - - 2019 - - - - 2020 - - - - 2021 - - - - 2022 - - - - Thereafter 101,697 6.01 101,589 6.65 Total borrowings $ 246,615 2.98 % $ 197,304 3.67 %

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2017
Income Taxes
Schedule of components of income tax expense (benefit)	2017 2016 2015 Current federal $ (2,407) $ 399 $ 220 Deferred federal 11,724 6,824 7,023 Deferred state 372 1,597 1,733 Expense due to enactment of federal tax reform 9,475 - - Total income tax expenses $ 19,164 $ 8,820 $ 8,976
Schedule of components of deferred tax assets and liabilities	2017 2016 Allowance for loan and lease losses $ 5,377 $ 7,057 Deferred compensation 650 735 Amortization of core deposit intangible 827 1,401 Goodwill amortization/impairment 6,087 10,127 Stock based compensation 866 946 OREO write-downs 2,385 5,110 Federal net operating loss (“NOL”) carryforward 7,240 19,362 State net operating loss (“NOL”) carryforward 7,020 7,735 Deferred tax credit - 2,058 Other assets 1,017 1,199 Total deferred tax assets 31,469 55,730 Accumulated depreciation on premises and equipment (384) (681) Mortgage servicing rights (2,086) (2,760) State tax benefits (2,389) (4,127) Other liabilities (545) (526) Total deferred tax liabilities (5,404) (8,094) Net deferred tax asset before adjustments related to other comprehensive loss 26,065 47,636 Tax effect of adjustments related to other comprehensive loss (709) 5,828 Net deferred tax asset $ 25,356 $ 53,464
Schedule of components of provision for deferred income taxes	2017 2016 2015 Provision for loan and lease losses $ 1,680 $ 42 $ 2,480 Deferred Compensation 85 (45) 97 Amortization of core deposit intangible 574 228 230 Stock based compensation 80 (132) (151) OREO write-downs 2,725 1,807 1,722 Federal net operating loss carryforward 12,122 4,743 2,896 State net operating loss carryforward 715 1,011 659 Deferred tax credit 2,058 (309) (198) Depreciation (297) 80 (201) Mortgage servicing rights (674) 276 164 Goodwill amortization/impairment 4,040 1,496 1,506 State tax benefits (1,738) (559) (604) Other, net 201 (217) 156 Total deferred tax expense $ 21,571 $ 8,421 $ 8,756
Schedule of difference between effective tax rates from federal statutory rates	Effective tax rates differ from federal statutory rates applied to financial statement income for the years ended December 31 due to the following: 2017 2016 2015 Tax at statutory federal income tax rate $ 11,817 $ 8,577 $ 8,526 Nontaxable interest income, net of disallowed interest deduction (1,976) (347) (253) BOLI income (501) (449) (487) State income taxes, net of federal benefit 1,775 1,148 1,126 Impact of Federal tax rate change 9,475 - - Impact of Illinois tax rate change (1,566) - - Other, net 140 (109) 64 Total tax at effective tax rate $ 19,164 $ 8,820 $ 8,976

Equity Compensation Plans (Tabl

Equity Compensation Plans (Tables)	12 Months Ended
	Dec. 31, 2017
Equity Compensation Plans
Summary of stock option activity in Incentive Plan	A summary of stock option activity in the Plans for the year ending December 31, 2017, is as follows (in dollars): Weighted- Weighted Average Average Remaining Exercise Contractual Aggregate Shares Price Term (years) Intrinsic Value Beginning outstanding 94,500 $ 25.82 - - Canceled (44,500) 27.75 - - Expired (41,000) 27.75 - - Ending outstanding 9,000 $ 7.49 1.1 $ 55,440 Exercisable at end of period 9,000 $ 7.49 1.1 $ 55,440
Summary of stock option activity as of each year	A summary of stock option activity as of each year is as follows (in dollars): 2017 2016 2015 Intrinsic value of options exercised $ - $ 2,790 $ - Cash received from option exercises - 11,235 - Tax benefit realized from option exercises - 91 - Weighted average fair value of options granted - - -
Summary of changes in nonvested shares of restricted share rights	December 31, 2017 Weighted Restricted Average Stock Shares Grant Date and Units Fair Value Unvested at January 1 409,000 $ 5.89 Granted 161,500 11.04 Vested (91,500) 5.07 Forfeited (14,000) 7.53 Unvested at December 31 465,000 $ 7.79

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2017
Earnings Per Share
Schedule of Earnings Per Share	The earnings per share, both basic and diluted, are included below as of December 31 (in thousands except for share data): 2017 2016 2015 Basic earnings per share: Weighted-average common shares outstanding 29,600,702 29,532,510 29,476,821 Net income $ 15,138 $ 15,684 $ 15,385 Preferred stock dividends and accretion - - 1,873 Net income available to common stockholders $ 15,138 $ 15,684 $ 13,512 Basic earnings per share $ 0.51 $ 0.53 $ 0.46 Diluted earnings per share: Weighted-average common shares outstanding 29,600,702 29,532,510 29,476,821 Dilutive effect of unvested restricted awards1 435,142 305,678 253,253 Dilutive effect of stock options 2,573 743 - Diluted average common shares outstanding 30,038,417 29,838,931 29,730,074 Net Income $ 15,138 $ 15,684 $ 13,512 Diluted earnings per share $ 0.50 $ 0.53 $ 0.46 Number of antidilutive options and warrants excluded from the diluted earnings per share calculation 815,339 900,839 977,839 1 Includes the common stock equivalents for restricted share awards that are dilutive .

Commitments (Tables)

Commitments (Tables)	12 Months Ended
	Dec. 31, 2017
Commitments
Schedule of contractual commitments due to letters of credit	The following table is a summary of financial instrument commitments (in thousands): December 31, 2017 December 31, 2016 Fixed Variable Total Fixed Variable Total Letters of credit: Borrower: Financial standby $ 177 $ 3,770 $ 3,947 $ 137 $ 4,047 $ 4,184 Commercial standby - 354 354 - 126 126 Performance standby 241 7,594 7,835 83 8,499 8,582 418 11,718 12,136 220 12,672 12,892 Non-borrower: Performance standby - 142 142 95 524 619 Total letters of credit $ 418 $ 11,860 $ 12,278 $ 315 $ 13,196 $ 13,511 Unused loan commitments: $ 82,942 $ 260,061 $ 343,003 $ 68,996 $ 270,989 $ 339,985

Regulatory & Capital Matters (T

Regulatory & Capital Matters (Tables)	12 Months Ended
	Dec. 31, 2017
Regulatory & Capital Matters
Schedule of capital levels and industry defined regulatory minimum required levels	Minimum Capital To Be Well Capitalized Under Adequacy with Capital Prompt Corrective Actual Conservation Buffer if applicable 1 Action Provisions 2 Amount Ratio Amount Ratio Amount Ratio 2017 Common equity tier 1 capital to risk weighted assets Consolidated $ 179,853 9.25 % $ 111,801 5.750 % N/A N/A Old Second Bank 249,417 12.88 111,347 5.750 $ 125,870 6.50 % Total capital to risk weighted assets Consolidated 251,383 12.93 179,837 9.250 N/A N/A Old Second Bank 266,873 13.78 179,142 9.250 193,667 10.00 Tier 1 capital to risk weighted assets Consolidated 233,927 12.03 140,978 7.250 N/A N/A Old Second Bank 249,417 12.88 140,394 7.250 154,917 8.00 Tier 1 capital to average assets Consolidated 233,927 10.08 92,828 4.00 N/A N/A Old Second Bank 249,417 10.79 92,462 4.00 115,578 5.00 2016 Common equity tier 1 capital to risk weighted assets Consolidated $ 154,537 8.76 % $ 90,411 5.125 % N/A N/A Old Second Bank 221,153 12.53 90,456 5.125 $ 114,724 6.50 % Total capital to risk weighted assets Consolidated 216,769 12.29 152,126 8.625 N/A N/A Old Second Bank 237,306 13.45 152,176 8.625 176,436 10.00 Tier 1 capital to risk weighted assets Consolidated 191,988 10.88 116,904 6.625 N/A N/A Old Second Bank 221,153 12.53 116,930 6.625 141,199 8.00 Tier 1 capital to average assets Consolidated 191,988 8.90 86,287 4.00 N/A N/A Old Second Bank 221,153 10.24 86,388 4.00 107,985 5.00 1 As of December 31, 2017, amounts shown are inclusive of a capital conservation buffer of 1.25% as compared to December 31, 2016, of 0.625%. 2 The Bank exceeded the general minimum regulatory requirements to be considered “well capitalized” .

Mortgage Banking Derivatives (T

Mortgage Banking Derivatives (Tables)	12 Months Ended
	Dec. 31, 2017
Not designated | Mortgage Banking Derivatives
Mortgage Banking Derivatives
Schedule of net gain or loss recorded on derivative activity	These mortgage banking derivatives are not designated in hedge relationships using the accepted accounting for derivative instruments and hedging activities at December 31 (dollars in thousands): 2017 2016 Forward contracts: Notional amount $ 16,500 $ 19,500 Fair value 3 190 Rate lock commitments: Notional amount $ 10,478 $ 12,480 Fair value 235 97

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Value Measurements
Schedule of balance of assets and liabilities which are measured at fair value on a recurring basis	December 31, 2017 Level 1 Level 2 Level 3 Total Assets: Securities available-for-sale U.S. Treasury $ 3,947 $ - $ - $ 3,947 U.S. government agencies - 13,061 - 13,061 U.S. government agencies mortgage-backed - 12,214 - 12,214 States and political subdivisions - 263,831 14,261 278,092 Corporate bonds - 833 - 833 Collateralized mortgage obligations - 63,671 2,268 65,939 Asset-backed securities - 112,932 - 112,932 Collateralized loan obligations - 54,421 - 54,421 Loans held-for-sale - 4,067 - 4,067 Mortgage servicing rights - - 6,944 6,944 Interest rate swap agreements - 727 - 727 Mortgage banking derivatives - 238 - 238 Total $ 3,947 $ 525,995 $ 23,473 $ 553,415 Liabilities: Interest rate swap agreements, including risk participation agreements $ - $ 2,014 $ - $ 2,014 Total $ - $ 2,014 $ - $ 2,014 December 31, 2016 Level 1 Level 2 Level 3 Total Assets: Securities available-for-sale U.S. government agencies mortgage-backed $ - $ 41,534 $ - $ 41,534 States and political subdivisions - 46,477 22,226 68,703 Corporate bonds - 10,630 - 10,630 Collateralized mortgage obligations - 167,808 3,119 170,927 Asset-backed securities - 138,407 - 138,407 Collateralized loan obligations - 101,637 - 101,637 Loans held-for-sale - 4,918 - 4,918 Mortgage servicing rights - - 6,489 6,489 Interest rate swap agreements - 673 - 673 Mortgage banking derivatives - 287 - 287 Total $ - $ 512,371 $ 31,834 $ 544,205 Liabilities: Interest rate swap agreements, including risk participation agreements $ - $ 1,667 $ - $ 1,667 Total $ - $ 1,667 $ - $ 1,667
Schedule of changes in Level 3 assets and liabilities measured at fair value on a recurring basis	Year Ended December 31, 2017 Securities available-for-sale Collateralized States and Mortgage Mortgage Political Servicing Obligation Subdivisions Rights Beginning balance January 1, 2017 $ 3,119 $ 22,226 $ 6,489 Total gains or losses Included in earnings (or changes in net assets) 40 - (270) Included in other comprehensive income 21 (796) - Purchases, issuances, sales, and settlements Purchases - 16,712 - Issuances - - 1,257 Settlements (912) (23,881) (532) Ending balance December 31, 2017 $ 2,268 $ 14,261 $ 6,944 Year Ended December 31, 2016 Securities available-for-sale Collateralized States and Mortgage Mortgage Political Servicing Obligation Subdivisions Rights Beginning balance January 1, 2016 $ - $ 111 $ 5,847 Transfers into Level 3 3,201 7,813 - Total gains or losses Included in earnings (or changes in net assets) - - (215) Included in other comprehensive income (82) 87 - Purchases, issuances, sales, and settlements Purchases - 14,296 - Issuances - - 1,561 Settlements - (81) (704) Ending balance December 31, 2016 $ 3,119 $ 22,226 $ 6,489
Schedule of quantitative information about level 3 fair value measurements	The following table and commentary presents quantitative (dollars in thousands) and qualitative information about Level 3 fair value measurements as of December 31, 2017: Weighted Measured at fair value Unobservable Average on a recurring basis: Fair Value Valuation Methodology Inputs Range of Input of Inputs Mortgage servicing rights $ 6,944 Discounted Cash Flow Discount Rate 10.0 - 34.3% 10.2 % Prepayment Speed 7.0 - 68.4% 9.6 % The following table and commentary presents quantitative (dollars in thousands) and qualitative information about Level 3 fair value measurements as of December 31, 2016: Weighted Measured at fair value Unobservable Average on a recurring basis: Fair Value Valuation Methodology Inputs Range of Input of Inputs Mortgage servicing rights $ 6,489 Discounted Cash Flow Discount Rate 10.0 - 17.0% 10.2 % Prepayment Speed 6.5 - 77.8% 9.6 % I
Schedule of assets measured at fair value on a nonrecurring basis	For assets measured at fair value on a nonrecurring basis at December 31, 2017, and December 31, 2016, respectively, the following tables provide the level of valuation assumptions used to determine each valuation and the carrying value of the related assets: December 31, 2017 Level 1 Level 2 Level 3 Total Impaired loans 1 $ - $ - $ 5,113 $ 5,113 Other real estate owned, net 2 - - 8,371 8,371 Total $ - $ - $ 13,484 $ 13,484 1 Represents carrying value and related write-downs of loans for which adjustments are substantially based on the appraised value of collateral for collateral-dependent loans, had a carrying amount of $5.3 million and a valuation allowance of $144,000, resulting in an increase of specific allocations within the ALLL of $856,000 for the year ending December 31, 2017. 2 OREO is measured at the lower of carrying or fair value less costs to sell, and had a net carrying amount of $8.4 million, which is made up of the outstanding balance of $17.4 million, net of a valuation allowance of $8.2 million and participations of $900,000, at December 31, 2017. December 31, 2016 Level 1 Level 2 Level 3 Total Impaired loans 1 $ - $ - $ - $ - Other real estate owned, net 2 - - 11,916 11,916 Total $ - $ - $ 11,916 $ 11,916 1 Represents carrying value and related write-downs of loans for which adjustments are substantially based on the appraised value of collateral for collateral-dependent loans, had a carrying amount and a valuation allowance of $1.0, resulting in a decrease of specific allocations within the provision for loan and lease losses of $1.0 million for the year ending December 31, 2016. 2 OREO is measured at the lower of carrying or fair value less costs to sell, and had a net carrying amount of $11.9 million, which is made up of the outstanding balance of $23.5 million, net of a valuation allowance of $14.1 million and participations of $1.7 million, at December 31, 2016.

Fair Values of Financial Inst47

Fair Values of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2017
Fair Values of Financial Instruments
Schedule of carrying amount and estimated fair values of financial instruments	December 31, 2017 Carrying Fair Amount Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 37,444 $ 37,444 $ 37,444 $ - $ - Interest bearing deposits with financial institutions 18,389 18,389 18,389 - - Securities available-for-sale 541,439 541,439 3,947 520,963 16,529 FHLBC and FRBC Stock 10,168 10,168 - 10,168 - Loans held-for-sale 4,067 4,067 - 4,067 - Loans, net 1,600,161 1,586,722 - - 1,586,722 Accrued interest receivable 8,595 8,595 - 8,595 - Financial liabilities: Noninterest bearing deposits $ 572,404 $ 572,404 $ 572,404 $ - $ - Interest bearing deposits 1,350,521 1,346,339 - 1,346,339 - Securities sold under repurchase agreements 29,918 29,918 - 29,918 - Other short-term borrowings 115,000 115,000 - 115,000 - Junior subordinated debentures 57,639 59,471 33,267 26,204 - Senior notes 44,058 46,743 - 46,743 - Interest rate swap agreements 1,287 1,287 - 1,287 - Borrowing interest payable 140 140 - 140 - Deposit interest payable 631 631 - 631 - December 31, 2016 Carrying Fair Amount Value Level 1 Level 2 Level 3 Financial assets: Cash and due from banks $ 33,805 $ 33,805 $ 33,805 $ - $ - Interest bearing deposits with financial institutions 13,529 13,529 13,529 - - Securities available-for-sale 531,838 531,838 - 506,493 25,345 FHLBC and FRBC Stock 7,918 7,918 - 7,918 - Loans held-for-sale 4,918 4,918 - 4,918 - Loans, net 1,462,651 1,453,429 - - 1,453,429 Accrued interest receivable 5,928 5,928 - 5,928 - Financial liabilities: Noninterest bearing deposits $ 513,688 $ 513,688 $ 513,688 $ - $ - Interest bearing deposits 1,353,097 1,351,000 - 1,351,000 - Securities sold under repurchase agreements 25,715 25,715 - 25,715 - Other short-term borrowings 70,000 70,000 - 70,000 - Junior subordinated debentures 57,591 55,163 32,404 22,759 - Subordinated debenture 43,998 43,998 - 43,998 - Interest rate swap agreements 994 994 - 994 - Borrowing interest payable 202 202 - 202 - Deposit interest payable 599 599 - 599 -

Financial Instruments with Of48

Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions (Tables)	12 Months Ended
	Dec. 31, 2017
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Summary information about the interest rate swap designated as a cash flow hedge	Summary information about the interest rate swap designated as a cash flow hedge is as follows: As of December 31, 2017 December 31, 2016 Notional amount $ 25,774 $ 25,774 Unrealized loss (1,287) (994)
Schedule of derivatives not designated as hedging instruments	The following table presents derivatives not designated as hedging instruments as of December 31, 2017, and periodic changes in the values of the interest rate swaps are reported in other noninterest income. Periodic changes in the value of the forward contracts related to mortgage loan origination are reported in the net gain on sales of mortgage loans. Asset Derivatives Liability Derivatives Notional or Contractual Balance Sheet Balance Sheet Amount Location Fair Value Location Fair Value Interest rate swap contracts net of credit valuation $ 153,433 Other Assets $ 727 Other Liabilities $ 727 Interest rate lock commitments and forward contracts 26,978 Other Assets 238 N/A - Total $ 965 $ 727 The following table presents derivatives not designated as hedging instruments as of December 31, 2016. Asset Derivatives Liability Derivatives Notional or Contractual Balance Sheet Balance Sheet Amount Location Fair Value Location Fair Value Interest rate swap contracts net of credit valuation $ 85,807 Other Assets $ 673 Other Liabilities $ 673 Interest rate lock commitments and forward contracts 31,980 Other Assets 287 N/A - Total $ 960 $ 673

Parent Company Condensed Fina49

Parent Company Condensed Financial Information (Tables)	12 Months Ended
	Dec. 31, 2017
Parent Company Condensed Financial Information
Schedule of condensed balance sheets	2017 2016 Assets Noninterest bearing deposit with bank subsidiary $ 23,011 $ 26,925 Investment in subsidiaries 263,389 228,646 Other assets 17,139 23,304 Total assets $ 303,539 $ 278,875 Liabilities and Stockholders’ Equity Junior subordinated debentures $ 57,639 $ 57,591 Senior notes 44,058 43,998 Other liabilities 1,492 2,076 Stockholders’ equity 200,350 175,210 Total liabilities and stockholders' equity $ 303,539 $ 278,875
Schedule of condensed statements of operations	2017 2016 2015 Operating Income Cash dividends received from subsidiaries $ - $ - $ 82,777 Other income 114 130 131 Total operating income 114 130 82,908 Operating Expenses Junior subordinated debentures 4,002 4,334 4,287 Senior notes 2,689 112 - Subordinated debt - 949 814 Other interest expense - 8 7 Other expenses 2,639 1,975 1,978 Total operating expense 9,330 7,378 7,086 Loss before income taxes and equity in undistributed net income of subsidiaries (9,216) (7,248) 75,822 Income tax benefit (16) (2,909) (2,771) Loss before equity in undistributed net income of subsidiaries (9,200) (4,339) 78,593 Equity in undistributed (over distributed) net income of subsidiaries 24,338 20,023 (63,208) Net income 15,138 15,684 15,385 Preferred stock dividends and accretion of discount - - 1,873 Net income available to common stockholders $ 15,138 $ 15,684 $ 13,512
Schedule of condensed statements of cash Flows	2017 2016 2015 Cash Flows from Operating Activities Net Income $ 15,138 $ 15,684 $ 15,385 Adjustments to reconcile net income to net cash from operating activities: Equity in (undistributed) over distributed net income of subsidiaries (24,338) (20,023) 63,208 Provision for deferred tax expense (benefit) 6,397 (1,039) (2,806) Net deferred tax expense due to DTA revaluation 3,908 - - Change in taxes payable (4,797) 330 (199) Change in other assets 74 171 36 Stock-based compensation 1,181 657 613 Other, net (15) 282 69 Net cash (used in) provided by operating activities (2,452) (3,938) 76,306 Cash Flows from Investing Activities Net cash provided by investing activities - - - Cash Flows from Financing Activities Dividend paid on preferred stock - - (2,417) Dividend paid on common stock (1,184) (888) - Purchases of treasury stock (236) (254) (117) Proceeds from the issuance of common stock - - - Proceeds from the issuance of senior notes - 43,994 - Payment of senior note issuance costs (42) - - Repayment of subordinated debt - (45,000) - Repayment of note payable - (500) - Proceeds from exercise of stock option - 11 - Redemption of preferred stock - - (47,331) Net cash used in financing activities (1,462) (2,637) (49,865) Net change in cash and cash equivalents (3,914) (6,575) 26,441 Cash and cash equivalents at beginning of year 26,925 33,500 7,059 Cash and cash equivalents at end of year $ 23,011 $ 26,925 $ 33,500

Summary of Significant Accoun50

Summary of Significant Accounting Policies - Dividend (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Jan. 17, 2017	Dec. 31, 2015	Dec. 31, 2014
90-Days or Greater Past Due Loans
Period from due date after which accrual of interest income is discontinued	90 days
Accumulated other comprehensive income (loss) breakdown
Unrealized gains on securities	$ 2,200,000
Unrealized losses on securities		$ 8,200,000
Unrealized Loss on Price Risk Cash Flow Derivatives, before Tax	760,000	596,000
Allowance for Loan Losses
Loans and Leases Receivable, Allowance	17,461,000	16,158,000		$ 16,223,000	$ 21,637,000
Dividends Payable, Amount Per Share			$ 0.01
All other
Allowance for Loan Losses
Loans and Leases Receivable, Allowance	$ 542,000	$ 435,000		$ 1,965,000	$ 2,506,000

Summary of Significant Accoun51

Summary of Significant Accounting Policies - Premises and Equipment (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Jan. 17, 2017	Dec. 31, 2016
Transfers and Servicing of Financial Assets
Mortgage loans serviced for others	$ 695,100,000		$ 668,200,000
Estimated stranded disproportionate tax expense,net	$ 318,000
Subsequent Events
Cash dividend declared (per share)		$ 0.01
Buildings | Minimum
Premises and equipment
Useful lives	25 years
Buildings | Maximum
Premises and equipment
Useful lives	40 years
Building improvements | Minimum
Premises and equipment
Useful lives	3 years
Building improvements | Maximum
Premises and equipment
Useful lives	15 years
Furniture and equipment | Minimum
Premises and equipment
Useful lives	3 years
Furniture and equipment | Maximum
Premises and equipment
Useful lives	10 years

Acquisitions (Details)

Acquisitions (Details) - USD ($)	Dec. 26, 2017	Dec. 31, 2016	Dec. 31, 2017	Oct. 28, 2016
Liabilities assumed:
Goodwill and acquisition costs		$ 8,500,000
Talmer
Business Acquisition [Line Items]
Loans payable				$ 223,800,000
Deposits			$ 48,900,000	48,900,000
Assets acquired:
Cash on hand				122,000
Loans				220,988,000
Premises and equipment, net				230,000
Goodwill				8,375,000
Core deposit intangible				659,000
Other assets acquired, including accrued interest, prepaids				573,000
Liabilities assumed:
Deposits- noninterest bearing demand				28,850,000
Deposits- interest bearing - Savings, NOW, Moneymarket				17,941,000
Deposits - Time				2,103,000
Other liabilities assumed, including escrow deposits and payables				574,000
Net assets acquired, or total cash paid for acquisition				$ 181,479,000
Acquisition expenses			$ 269,000
Greater Chicago Financial Corp
Business Acquisition [Line Items]
Net cash paid	$ 41,100,000
Subordinated debentures retired	6,300,000
Total assets	342,600,000
Debt Conversion, Original Debt, Amount	2,000,000
Assets acquired:
Loans	234,400,000
Liabilities assumed:
Acquisition expenses	$ 65,000

Cash and Due from Banks (Detail

Cash and Due from Banks (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Other disclosures
Balances	$ 11	$ 11.8
Federal Reserve Bank average regulatory reserve
Other disclosures
Balances	$ 10.6	$ 10.5

Securities - Investment Portfol

Securities - Investment Portfolio (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Securities
Pretax realized losses on sale of available-for-sale securities	$ 1,893,000	$ 3,888,000	$ 284,000
FHLB and FRB Stock
FHLBC stock	5,400,000	$ 3,100,000
FRB stock	$ 4,800,000

Securities - Amortized Cost and

Securities - Amortized Cost and Fair Value (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Securities Available-for-Sale
Amortized Cost	$ 537,645,000	$ 545,433,000
Gross Unrealized Gains	8,467,000	1,011,000
Gross Unrealized Losses	(4,673,000)	(14,606,000)
Fair Value	541,439,000	531,838,000
Other disclosures
Purchases	343,470,000	210,681,000	$ 196,082,000
Sales	232,462,000	306,400,000	$ 70,176,000
Securities pledged to secure deposits and for other purposes	301,000,000	262,600,000
U.S. Treasury
Securities Available-for-Sale
Amortized Cost	4,002,000
Gross Unrealized Losses	(55,000)
Fair Value	3,947,000
US Treasury and Government
Securities Available-for-Sale
Amortized Cost	13,062,000
Gross Unrealized Gains	8,000
Gross Unrealized Losses	(9,000)
Fair Value	13,061,000
U.S. government agencies
Securities Available-for-Sale
Fair Value	13,061,000
U.S. government agencies mortgage-backed
Securities Available-for-Sale
Amortized Cost	12,372,000	42,511,000
Gross Unrealized Gains	7,000
Gross Unrealized Losses	(165,000)	(977,000)
Fair Value	12,214,000	41,534,000
States and political subdivisions
Securities Available-for-Sale
Amortized Cost	272,240,000	68,718,000
Gross Unrealized Gains	7,116,000	258,000
Gross Unrealized Losses	(1,264,000)	(273,000)
Fair Value	278,092,000	68,703,000
Corporate bonds
Securities Available-for-Sale
Amortized Cost	823,000	10,957,000
Gross Unrealized Gains	21,000	9,000
Gross Unrealized Losses	(11,000)	(336,000)
Fair Value	833,000	10,630,000
Collateralized mortgage obligations
Securities Available-for-Sale
Amortized Cost	66,892,000	174,352,000
Gross Unrealized Gains	202,000	374,000
Gross Unrealized Losses	(1,155,000)	(3,799,000)
Fair Value	65,939,000	170,927,000
Asset-backed securities
Securities Available-for-Sale
Amortized Cost	113,983,000	146,391,000
Gross Unrealized Gains	862,000	341,000
Gross Unrealized Losses	(1,913,000)	(8,325,000)
Fair Value	112,932,000	138,407,000
Collateralized loan obligations
Securities Available-for-Sale
Amortized Cost	54,271,000	102,504,000
Gross Unrealized Gains	251,000	29,000
Gross Unrealized Losses	(101,000)	(896,000)
Fair Value	54,421,000	$ 101,637,000
U.S. government agency mortgage-backed
Securities Available-for-Sale
Fair Value	12,214,000
States and political subdivisions & collateralized loan obligations
Other disclosures
Purchases	270,200,000
Sales	146,900,000
Paydown	13,000,000
Talmer
Other disclosures
Decline in securities	9,600,000
Stockholders' Equity | GCO Education Loan Funding Corp | Asset-backed securities | Credit Concentration Risk
Securities Available-for-Sale
Amortized Cost	27,625,000
Fair Value	26,588,000
Stockholders' Equity | Towd Point Mortgage Trust | Asset-backed securities | Credit Concentration Risk
Securities Available-for-Sale
Amortized Cost	29,312,000
Fair Value	29,210,000
Stockholders' Equity | Student Marketing Association [Member] | Asset-backed securities | Credit Concentration Risk
Securities Available-for-Sale
Amortized Cost	25,696,000
Fair Value	$ 25,917,000
Minimum | Stockholders' Equity | GCO Education Loan Funding Corp | Asset-backed securities | Credit Concentration Risk
Other disclosures
Credit risk as a percentage of benchmark	10.00%
Minimum | Stockholders' Equity | Towd Point Mortgage Trust | Asset-backed securities | Credit Concentration Risk
Other disclosures
Credit risk as a percentage of benchmark	10.00%
Minimum | Stockholders' Equity | Student Marketing Association [Member] | Asset-backed securities | Credit Concentration Risk
Other disclosures
Credit risk as a percentage of benchmark	10.00%

Securities - Contractural Matur

Securities - Contractural Maturities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Securities Available-for-Sale, Amortized Cost
Due in one year or less	$ 6,200
Due after one year through five years	4,346
Due after five years through ten years	6,013
Due after ten years	273,568
Debt securities excluding securities not due at a single maturity date	290,127
Total	$ 537,645	$ 545,433
Securities Available-for-Sale, Weighted Average Yield
Due in one year or less (as a percent)	2.41%
Due after one year through five years (as a percent)	2.03%
Due after five years through ten years (as a percent)	3.29%
Due after ten years (as a percent)	2.95%
Debt securities (as a percent)	2.93%
Total (as a percent)	2.99%
Securities Available-for-Sale, Fair Value
Due in one year or less	$ 6,185
Due after one year through five years	4,279
Due after five years through ten years	6,234
Due after ten years	279,235
Debt securities	295,933
Fair Value	541,439	531,838
Collateralized mortgage obligations
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	79,264
Total	$ 66,892	174,352
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	2.94%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 78,153
Fair Value	65,939	170,927
Asset-backed securities
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	113,983
Total	$ 113,983	146,391
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	2.56%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 112,932
Fair Value	112,932	138,407
Collateralized loan obligations
Securities Available-for-Sale, Amortized Cost
Securities not due at a single maturity date	54,271
Total	$ 54,271	102,504
Securities Available-for-Sale, Weighted Average Yield
Securities not due at a single maturity date, Weighted Average Yield (as a percent)	4.32%
Securities Available-for-Sale, Fair Value
Securities not due at a single maturity date	$ 54,421
Fair Value	$ 54,421	$ 101,637

Securities - Unrealized Loss Po

Securities - Unrealized Loss Positions (Details) $ in Thousands	Dec. 31, 2017USD ($)security	Dec. 31, 2016USD ($)security
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	26	44
Greater than 12 months in an unrealized loss position | security	22	34
Total | security	48	78
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 1,457	$ 5,143
Greater than 12 months in an unrealized loss position	3,216	9,463
Total	4,673	14,606
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	102,830	216,050
Greater than 12 months in an unrealized loss position	108,651	213,060
Total	$ 211,481	$ 429,110
U.S. Treasury
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	1
Total | security	1
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 55
Total	55
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	3,947
Total	$ 3,947
U.S. government agencies
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	2	11
Greater than 12 months in an unrealized loss position | security		1
Total | security	2	12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 9	$ 957
Greater than 12 months in an unrealized loss position		20
Total	9	977
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	6,550	40,636
Greater than 12 months in an unrealized loss position		898
Total	$ 6,550	$ 41,534
U.S. government agency mortgage-backed
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	4
Greater than 12 months in an unrealized loss position | security	5
Total | security	9
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 24
Greater than 12 months in an unrealized loss position	141
Total	165
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	5,501
Greater than 12 months in an unrealized loss position	4,843
Total	$ 10,344
States and political subdivisions
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	13	12
Greater than 12 months in an unrealized loss position | security	1
Total | security	14	12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 1,237	$ 273
Greater than 12 months in an unrealized loss position	27
Total	1,264	273
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	45,985	35,241
Greater than 12 months in an unrealized loss position	1,512
Total	$ 47,497	$ 35,241
Corporate bonds
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security		1
Greater than 12 months in an unrealized loss position | security	1	2
Total | security	1	3
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position		$ 183
Greater than 12 months in an unrealized loss position	$ 11	153
Total	11	336
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position		4,817
Greater than 12 months in an unrealized loss position	332	5,328
Total	$ 332	$ 10,145
Collateralized mortgage obligations
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	3	16
Greater than 12 months in an unrealized loss position | security	8	7
Total | security	11	23
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 31	$ 3,402
Greater than 12 months in an unrealized loss position	1,124	397
Total	1,155	3,799
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	11,534	117,752
Greater than 12 months in an unrealized loss position	40,219	18,109
Total	$ 51,753	$ 135,861
Asset-backed securities
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security		4
Greater than 12 months in an unrealized loss position | security	7	12
Total | security	7	16
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position		$ 328
Greater than 12 months in an unrealized loss position	$ 1,913	7,997
Total	1,913	8,325
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position		17,604
Greater than 12 months in an unrealized loss position	61,745	107,112
Total	$ 61,745	$ 124,716
Collateralized loan obligations
Securities Available-for-Sale, Number of Securities
Less than 12 months in an unrealized loss position | security	3
Greater than 12 months in an unrealized loss position | security		12
Total | security	3	12
Securities Available-for-Sale, Unrealized Losses
Less than 12 months in an unrealized loss position	$ 101
Greater than 12 months in an unrealized loss position		$ 896
Total	101	896
Securities Available-for-Sale, Fair Value
Less than 12 months in an unrealized loss position	29,313
Greater than 12 months in an unrealized loss position		81,613
Total	$ 29,313	$ 81,613

Securities - Realized Gain (Los

Securities - Realized Gain (Loss) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Securities
Sales	$ 232,462,000	$ 306,400,000	$ 70,176,000
Gross realized gains on securities	2,367,000	1,675,000	106,000
Gross realized losses on securities	(1,893,000)	(3,888,000)	(284,000)
Securities (losses) gains, net	474,000	(2,213,000)	(178,000)
Income tax benefit (expense) on net realized gains	$ (198,000)	$ 882,000	$ 71,000

Loans - Major Classifications (

Loans - Major Classifications (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans
Total loans, gross	$ 1,616,942	$ 1,477,592
Net deferred loan fees	680	1,217
Total Loans	1,617,622	1,478,809	$ 1,133,715
Construction Loans
Loans
Total Loans	85,162	64,720	19,806
Other
Loans
Total loans, gross	10,609	11,973
Commercial
Loans
Total loans, gross	272,851	228,113
Total Loans	272,851	228,113	141,315
Real estate - commercial
Loans
Total loans, gross	750,991	736,247
Total Loans	750,991	736,247	605,721
Real estate - commercial | Construction Loans
Loans
Total loans, gross	85,162	64,720
Real estate - residential
Loans
Total loans, gross	426,230	377,851
Total Loans	426,230	377,851	351,007
Consumer
Loans
Total loans, gross	2,774	3,237
Total Loans	2,774	3,237	$ 4,216
Lease financing receivables
Loans
Total loans, gross	68,325	55,451
Total Loans	$ 68,325	$ 55,451

Loans - Major Classifications -

Loans - Major Classifications - Loan Concentrations (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Oct. 28, 2016
Loans
Growth in loan balance	$ 138,800
Total real estate
Loans
Loans receivable as a percentage of total portfolio	78.00%	79.70%
Talmer
Loans
Loans			$ 220,988

Loans - Aging Analysis (Details

Loans - Aging Analysis (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Aged analysis of past due loans
Total Past Due	$ 5,606	$ 5,139
Current	1,597,628	1,458,387
Nonaccrual	14,388	15,283
Total Loans	1,617,622	1,478,809	$ 1,133,715
Recorded Investment 90 days or Greater Past Due and Accruing	254
30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	4,212	3,959
60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	1,146	1,180
90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	248
Multifamily
Aged analysis of past due loans
Current	125,049	96,502,000
Nonaccrual	4,723
Total Loans	129,772	96,502,000
Commercial
Aged analysis of past due loans
Total Past Due	1,270	131
Current	271,581	227,742
Nonaccrual		240
Total Loans	272,851	228,113	141,315
Commercial | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	995	57
Commercial | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	275	74
Lease financing receivables
Aged analysis of past due loans
Total Past Due		286
Current	68,147	54,799
Nonaccrual	178	366
Total Loans	68,325	55,451
Lease financing receivables | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		286
Real estate - commercial
Aged analysis of past due loans
Total Loans	750,991	736,247	605,721
Real estate - commercial | Owner occupied general purpose
Aged analysis of past due loans
Total Past Due	1,136	758
Current	144,267	135,599
Nonaccrual	455	879
Total Loans	145,858	137,236
Real estate - commercial | Owner occupied general purpose | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	1,136	758
Real estate - commercial | Owner occupied special purpose
Aged analysis of past due loans
Total Past Due	226
Current	170,546	177,755
Nonaccrual	342	385
Total Loans	171,114	178,140
Real estate - commercial | Owner occupied special purpose | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	226
Real estate - commercial | Non-owner occupied general purpose
Aged analysis of past due loans
Total Past Due	593	1,046
Current	273,203	229,315
Nonaccrual	1,163	1,930
Total Loans	274,959	232,291
Real estate - commercial | Non-owner occupied general purpose | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		667
Real estate - commercial | Non-owner occupied general purpose | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	593	379
Real estate - commercial | Non-owner occupied special purpose
Aged analysis of past due loans
Total Past Due	248
Current	92,923	118,052
Nonaccrual		1,013
Total Loans	93,171	119,065
Recorded Investment 90 days or Greater Past Due and Accruing	254
Real estate - commercial | Non-owner occupied special purpose | 90 Days or Greater Past Due
Aged analysis of past due loans
Total Past Due	248
Real estate - commercial | Retail properties
Aged analysis of past due loans
Current	49,538	53,474
Nonaccrual	1,081	1,179
Total Loans	50,619	54,653
Real estate - commercial | Farm
Aged analysis of past due loans
Total Past Due		1,353
Current	15,270	13,509
Total Loans	15,270	14,862
Real estate - commercial | Farm | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		1,353
Real estate - residential
Aged analysis of past due loans
Total Loans	426,230	377,851	351,007
Real estate - residential | Investor
Aged analysis of past due loans
Total Past Due		237
Current	55,248	54,924
Nonaccrual	372	936
Total Loans	55,620	56,097
Real estate - residential | Investor | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		237
Real estate - residential | Multifamily
Aged analysis of past due loans
Total Loans		96,502
Real estate - residential | Owner occupied
Aged analysis of past due loans
Total Past Due	74	274
Current	123,838	116,900
Nonaccrual	4,674	6,452
Total Loans	128,586	123,626
Real estate - residential | Owner occupied | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	74	274
Real estate - residential | Revolving and junior liens
Aged analysis of past due loans
Total Past Due	769	630
Current	110,291	99,374
Nonaccrual	1,192	1,622
Total Loans	112,252	101,626
Real estate - residential | Revolving and junior liens | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	491	225
Real estate - residential | Revolving and junior liens | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due	278	405
Consumer
Aged analysis of past due loans
Total Past Due		46
Current	2,767	3,191
Nonaccrual	7
Total Loans	2,774	3,237	4,216
Consumer | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		10
Consumer | 60 to 89 Days Past Due
Aged analysis of past due loans
Total Past Due		36
All other
Aged analysis of past due loans
Total Past Due	37	14
Current	11,252	13,176
Total Loans	11,289	13,190	11,650
All other | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	37	14
Construction Loans
Aged analysis of past due loans
Total Loans	85,162	64,720	$ 19,806
Construction Loans | Real estate - commercial | Homebuilder
Aged analysis of past due loans
Total Past Due	129
Current	2,221	3,883
Total Loans	2,350	3,883
Construction Loans | Real estate - commercial | Homebuilder | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	129
Construction Loans | Real estate - commercial | Land
Aged analysis of past due loans
Total Past Due	1,124
Current	1,319	3,029
Total Loans	2,443	3,029
Construction Loans | Real estate - commercial | Land | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due	1,124
Construction Loans | Real estate - commercial | Commercial speculative
Aged analysis of past due loans
Current	32,028	22,654
Nonaccrual		74
Total Loans	32,028	22,728
Construction Loans | Real estate - commercial | All other
Aged analysis of past due loans
Total Past Due		364
Current	48,140	34,509
Nonaccrual	201	207
Total Loans	$ 48,341	35,080
Construction Loans | Real estate - commercial | All other | 30 to 59 Days Past Due
Aged analysis of past due loans
Total Past Due		$ 364

Loans - Inclusion (Details)

Loans - Inclusion (Details)	12 Months Ended
	Dec. 31, 2017USD ($)
Minimum
Loans by risk rating
Loan commitment for inclusion in credit quality analysis	$ 50,000

Loans - Credit Quality (Details

Loans - Credit Quality (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loans by risk rating
Total Loans	$ 1,617,622	$ 1,478,809	$ 1,133,715
Multifamily
Loans by risk rating
Total Loans	129,772	96,502,000
Commercial
Loans by risk rating
Total Loans	272,851	228,113	141,315
Lease financing receivables
Loans by risk rating
Total Loans	68,325	55,451
Real estate - commercial
Loans by risk rating
Total Loans	750,991	736,247	605,721
Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	145,858	137,236
Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	171,114	178,140
Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	274,959	232,291
Real estate - commercial | Non-owner occupied special purpose
Loans by risk rating
Total Loans	93,171	119,065
Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	50,619	54,653
Real estate - commercial | Farm
Loans by risk rating
Total Loans	15,270	14,862
Real estate - residential
Loans by risk rating
Total Loans	426,230	377,851	351,007
Real estate - residential | Investor
Loans by risk rating
Total Loans	55,620	56,097
Real estate - residential | Multifamily
Loans by risk rating
Total Loans		96,502
Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	128,586	123,626
Real estate - residential | Revolving and junior liens
Loans by risk rating
Total Loans	112,252	101,626
Consumer
Loans by risk rating
Total Loans	2,774	3,237	4,216
All other
Loans by risk rating
Total Loans	11,289	13,190	11,650
Pass
Loans by risk rating
Total Loans	1,583,352	1,430,321
Pass | Multifamily
Loans by risk rating
Total Loans	125,049
Pass | Commercial
Loans by risk rating
Total Loans	270,889	214,028
Pass | Lease financing receivables
Loans by risk rating
Total Loans	67,500	53,366
Pass | Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	142,843	135,503
Pass | Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	169,621	172,353
Pass | Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	271,731	229,448
Pass | Real estate - commercial | Non-owner occupied special purpose
Loans by risk rating
Total Loans	89,582	114,293
Pass | Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	48,321	52,207
Pass | Real estate - commercial | Farm
Loans by risk rating
Total Loans	11,755	11,840
Pass | Real estate - residential | Investor
Loans by risk rating
Total Loans	55,172	55,001
Pass | Real estate - residential | Multifamily
Loans by risk rating
Total Loans		96,502
Pass | Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	122,759	115,831
Pass | Real estate - residential | Revolving and junior liens
Loans by risk rating
Total Loans	110,353	99,286
Pass | Consumer
Loans by risk rating
Total Loans	2,754	3,236
Pass | All other
Loans by risk rating
Total Loans	11,289	13,165
Special Mention
Loans by risk rating
Total Loans	10,965	22,004
Special Mention | Commercial
Loans by risk rating
Total Loans	1,962	11,558
Special Mention | Lease financing receivables
Loans by risk rating
Total Loans		976
Special Mention | Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	1,927	53
Special Mention | Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	1,152	5,402
Special Mention | Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	2,065	913
Special Mention | Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	1,217	1,267
Special Mention | Real estate - commercial | Farm
Loans by risk rating
Total Loans	1,029	1,240
Special Mention | Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	561	570
Special Mention | All other
Loans by risk rating
Total Loans		25
Substandard
Loans by risk rating
Total Loans	23,305	26,484
Substandard | Multifamily
Loans by risk rating
Total Loans	4,723
Substandard | Commercial
Loans by risk rating
Total Loans		2,527
Substandard | Lease financing receivables
Loans by risk rating
Total Loans	825	1,109
Substandard | Real estate - commercial | Owner occupied general purpose
Loans by risk rating
Total Loans	1,088	1,680
Substandard | Real estate - commercial | Owner occupied special purpose
Loans by risk rating
Total Loans	341	385
Substandard | Real estate - commercial | Non-owner occupied general purpose
Loans by risk rating
Total Loans	1,163	1,930
Substandard | Real estate - commercial | Non-owner occupied special purpose
Loans by risk rating
Total Loans	3,589	4,772
Substandard | Real estate - commercial | Retail properties
Loans by risk rating
Total Loans	1,081	1,179
Substandard | Real estate - commercial | Farm
Loans by risk rating
Total Loans	2,486	1,782
Substandard | Real estate - residential | Investor
Loans by risk rating
Total Loans	448	1,096
Substandard | Real estate - residential | Owner occupied
Loans by risk rating
Total Loans	5,266	7,225
Substandard | Real estate - residential | Revolving and junior liens
Loans by risk rating
Total Loans	1,899	2,340
Substandard | Consumer
Loans by risk rating
Total Loans	20	1
Construction Loans
Loans by risk rating
Total Loans	85,162	64,720	$ 19,806
Construction Loans | Real estate - commercial | Homebuilder
Loans by risk rating
Total Loans	2,350	3,883
Construction Loans | Real estate - commercial | Land
Loans by risk rating
Total Loans	2,443	3,029
Construction Loans | Real estate - commercial | Commercial speculative
Loans by risk rating
Total Loans	32,028	22,728
Construction Loans | Real estate - commercial | All other
Loans by risk rating
Total Loans	48,341	35,080
Construction Loans | Pass | Real estate - commercial | Homebuilder
Loans by risk rating
Total Loans	2,350	3,883
Construction Loans | Pass | Real estate - commercial | Land
Loans by risk rating
Total Loans	2,443	3,029
Construction Loans | Pass | Real estate - commercial | Commercial speculative
Loans by risk rating
Total Loans	32,028	22,654
Construction Loans | Pass | Real estate - commercial | All other
Loans by risk rating
Total Loans	46,913	34,696
Construction Loans | Special Mention | Real estate - commercial | All other
Loans by risk rating
Total Loans	1,052
Construction Loans | Substandard | Real estate - commercial | Commercial speculative
Loans by risk rating
Total Loans		74
Construction Loans | Substandard | Real estate - commercial | All other
Loans by risk rating
Total Loans	$ 376	$ 384

Loans - Repossessed Assets (Det

Loans - Repossessed Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Repossessed and foreclosed assets
Other real estate owned	$ 8,371	$ 11,916	$ 19,141	$ 31,982
Consumer
Repossessed and foreclosed assets
Mortgage loans in process of foreclosure	$ 1,300	$ 1,800

Loans - Impaired Loans - Record

Loans - Impaired Loans - Recorded Investment, Unpaid Principal Balance and Related Allowance (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Recorded Investment
With no related allowance recorded	$ 14,855	$ 21,238
With an allowance recorded	5,257	1,049
Total impaired loans	20,112	22,287
Unpaid Principal Balance
With no related allowance recorded	17,792	25,321
With an allowance recorded	5,257	1,448
Total impaired loans	23,049	26,769
Related Allowance
With an allowance recorded	144	1,049
Multifamily
Recorded Investment
With no related allowance recorded	4,723
Unpaid Principal Balance
With no related allowance recorded	4,965
Commercial
Recorded Investment
With no related allowance recorded		240
Unpaid Principal Balance
With no related allowance recorded		388
Lease financing receivables
Recorded Investment
With no related allowance recorded	178	366
Unpaid Principal Balance
With no related allowance recorded	213	371
Real estate - commercial | Owner occupied general purpose
Recorded Investment
With no related allowance recorded	455	1,881
Unpaid Principal Balance
With no related allowance recorded	495	2,131
Real estate - commercial | Owner occupied special purpose
Recorded Investment
With no related allowance recorded	342	385
Unpaid Principal Balance
With no related allowance recorded	498	518
Real estate - commercial | Non-owner occupied general purpose
Recorded Investment
With no related allowance recorded	1,163	1,744
With an allowance recorded		246
Unpaid Principal Balance
With no related allowance recorded	1,538	2,010
With an allowance recorded		595
Related Allowance
With an allowance recorded		246
Real estate - commercial | Non-owner occupied special purpose
Recorded Investment
With no related allowance recorded		1,013
Unpaid Principal Balance
With no related allowance recorded		1,649
Real estate - commercial | Retail properties
Recorded Investment
With no related allowance recorded	1,081	1,179
Unpaid Principal Balance
With no related allowance recorded	1,177	1,235
Real estate - residential | Investor
Recorded Investment
With no related allowance recorded	372	1,841
With an allowance recorded	829
Unpaid Principal Balance
With no related allowance recorded	676	2,308
With an allowance recorded	829
Related Allowance
With an allowance recorded	10
Real estate - residential | Owner occupied
Recorded Investment
With no related allowance recorded	5,208	9,824
With an allowance recorded	3,443	803
Unpaid Principal Balance
With no related allowance recorded	6,680	11,391
With an allowance recorded	3,443	853
Related Allowance
With an allowance recorded	43	803
Real estate - residential | Revolving and junior liens
Recorded Investment
With no related allowance recorded	1,125	2,484
With an allowance recorded	985
Unpaid Principal Balance
With no related allowance recorded	1,313	3,018
With an allowance recorded	985
Related Allowance
With an allowance recorded	91
Consumer
Recorded Investment
With no related allowance recorded	7
Unpaid Principal Balance
With no related allowance recorded	8
Construction Loans | Real estate - commercial | Commercial speculative
Recorded Investment
With no related allowance recorded		74
Unpaid Principal Balance
With no related allowance recorded		81
Construction Loans | Real estate - commercial | All other
Recorded Investment
With no related allowance recorded	201	207
Unpaid Principal Balance
With no related allowance recorded	$ 229	$ 221

Loans - Impaired Loans - Averag

Loans - Impaired Loans - Average Recorded Investment and Interest Income Recognized (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Average Recorded Investment
With no related allowance recorded	$ 18,047	$ 20,982	$ 27,868
With an allowance recorded	3,153	605	518
Total impaired loans	21,200	21,587	28,386
Interest Income Recognized
With no related allowance recorded	45	323	303
With an allowance recorded	201		3
Total impaired loans	246	323	306
Commercial
Average Recorded Investment
With no related allowance recorded	120	155	785
With an allowance recorded		2	2
Lease financing receivables
Average Recorded Investment
With no related allowance recorded	272	183
Real estate - commercial | Owner occupied general purpose
Average Recorded Investment
With no related allowance recorded	1,168	2,098	4,720
Interest Income Recognized
With no related allowance recorded		87	82
Real estate - commercial | Owner occupied special purpose
Average Recorded Investment
With no related allowance recorded	364	574	1,280
Real estate - commercial | Non-owner occupied general purpose
Average Recorded Investment
With no related allowance recorded	1,453	1,395	2,939
With an allowance recorded	123	123	38
Interest Income Recognized
With no related allowance recorded		2	3
Real estate - commercial | Non-owner occupied special purpose
Average Recorded Investment
With no related allowance recorded	507	507	712
Real estate - commercial | Retail properties
Average Recorded Investment
With no related allowance recorded	1,130	589
Real estate - commercial | Farm
Average Recorded Investment
With no related allowance recorded		636	636
Real estate - residential | Investor
Average Recorded Investment
With no related allowance recorded	1,106	1,874	2,251
With an allowance recorded	414		67
Interest Income Recognized
With no related allowance recorded		47	51
With an allowance recorded	43
Real estate - residential | Multifamily
Average Recorded Investment
With no related allowance recorded	2,362
Real estate - residential | Owner occupied
Average Recorded Investment
With no related allowance recorded	7,516	10,181	10,979
With an allowance recorded	2,123	457	68
Interest Income Recognized
With no related allowance recorded	44	158	160
With an allowance recorded	123
Real estate - residential | Revolving and junior liens
Average Recorded Investment
With no related allowance recorded	1,804	2,608	2,484
With an allowance recorded	493	23	208
Interest Income Recognized
With no related allowance recorded	1	29	7
With an allowance recorded	35		3
Consumer
Average Recorded Investment
With no related allowance recorded	4
Construction Loans | Real estate - commercial | Homebuilder
Average Recorded Investment
With no related allowance recorded			895
Construction Loans | Real estate - commercial | Commercial speculative
Average Recorded Investment
With no related allowance recorded	37	79	42
Construction Loans | Real estate - commercial | All other
Average Recorded Investment
With no related allowance recorded	$ 204	$ 103	145
With an allowance recorded			$ 135

Loans - TDR (Details)

Loans - TDR (Details) $ in Thousands	12 Months Ended		24 Months Ended
	Dec. 31, 2017USD ($)contract	Dec. 31, 2016USD ($)contract	Dec. 31, 2017USD ($)item
Troubled debt restructurings - modified during the period
# of contracts | contract	11	10
Pre-modification recorded investment	$ 690	$ 1,791
Post-modification recorded investment	761	1,472
TDR's defaulted
# of contracts | item			0
Other information
Commitments to lend to borrowers whose loans were classified as impaired	0		$ 0
Total Past Due	$ 5,606	$ 5,139	5,606
Other
Troubled debt restructurings - modified during the period
# of contracts | contract	1	2
Pre-modification recorded investment	$ 97	$ 312
Post-modification recorded investment	131	$ 205
HAMP
Troubled debt restructurings - modified during the period
# of contracts | contract		2
Pre-modification recorded investment		$ 419
Post-modification recorded investment		262
Real estate - commercial | Owner occupied special purpose
Other information
Total Past Due	226		226
Real estate - commercial | Owner occupied general purpose
Other information
Total Past Due	1,136	758	1,136
Real estate - commercial | Non-owner occupied general purpose
Other information
Total Past Due	$ 593	1,046	593
Real estate - residential
Troubled debt restructurings - modified during the period
# of contracts | contract	1
Pre-modification recorded investment	$ 41
Post-modification recorded investment	42
Real estate - residential | Investor
Other information
Total Past Due		237
Real estate - residential | Owner occupied
Other information
Total Past Due	$ 74	274	74
Real estate - residential | Owner occupied | HAMP
Troubled debt restructurings - modified during the period
# of contracts | contract	2
Pre-modification recorded investment	$ 184
Post-modification recorded investment	189
Real estate - residential | Revolving and junior liens
Other information
Total Past Due	$ 769	$ 630	769
Real estate - residential | Revolving and junior liens | Other
Troubled debt restructurings - modified during the period
# of contracts | contract	6	3
Pre-modification recorded investment	$ 319	$ 808
Post-modification recorded investment	$ 350	$ 777
Real estate - residential | Revolving and junior liens | HAMP
Troubled debt restructurings - modified during the period
# of contracts | contract	1	3
Pre-modification recorded investment	$ 49	$ 252
Post-modification recorded investment	49	228
Commercial
Other information
Total Past Due	1,270	$ 131	1,270
90 Days or Greater Past Due
Other information
Total Past Due	248		248
Principal Officers, Directors, and Affiliates | 90 Days or Greater Past Due
Other information
Total Past Due	$ 0		$ 0

Loans - Related Parties (Detail

Loans - Related Parties (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Loans to principal officers, directors, and their affiliates
Beginning balance	$ 1,703	$ 1,787
New loans	20	157
Repayments and other reductions	(199)	(241)
Ending balance	$ 1,524	$ 1,703

Allowance for Loan Losses (Deta

Allowance for Loan Losses (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for loan losses:
Beginning Balance	$ 16,158	$ 16,223	$ 21,637
Charge-offs	2,306	3,190	4,770
Recoveries	1,809	2,375	3,756
Provision (release)	1,800	750	(4,400)
Ending Balance	17,461	16,158	16,223
Ending balance: Individually evaluated for impairment	144	1,049	34
Ending balance: Collectively evaluated for impairment	17,317	15,109	16,189
Loans:
Ending balance	1,617,622	1,478,809	1,133,715
Ending balance: Individually evaluated for impairment	20,112	22,287	20,886
Ending balance: Collectively evaluated for impairment	1,597,510	1,456,522	1,112,829
Commercial
Allowance for loan losses:
Beginning Balance		2,096	1,644
Charge-offs			993
Recoveries			451
Provision (release)			994
Ending Balance			2,096
Ending balance: Individually evaluated for impairment			3
Ending balance: Collectively evaluated for impairment			2,093
Loans:
Ending balance	272,851	228,113	141,315
Ending balance: Individually evaluated for impairment			73
Ending balance: Collectively evaluated for impairment			141,242
Commercial without Leases
Allowance for loan losses:
Beginning Balance	1,629	1,463
Charge-offs	25	95
Recoveries	30	32
Provision (release)	819	229
Ending Balance	2,453	1,629	1,463
Ending balance: Collectively evaluated for impairment	2,453	1,629
Loans:
Ending balance	272,851	228,113
Ending balance: Individually evaluated for impairment		240
Ending balance: Collectively evaluated for impairment	272,851	227,873
Commercial leases
Allowance for loan losses:
Beginning Balance	633	633
Charge-offs	215	23
Recoveries		5
Provision (release)	274	18
Ending Balance	692	633	633
Ending balance: Collectively evaluated for impairment	692	633
Loans:
Ending balance	68,325
Ending balance: Individually evaluated for impairment	178	366
Ending balance: Collectively evaluated for impairment	68,147	55,085
Lease financing receivables
Loans:
Ending balance	68,325	55,451
Real estate - commercial
Allowance for loan losses:
Beginning Balance	9,547	9,013	12,577
Charge-offs	309	1,633	1,653
Recoveries	161	640	1,595
Provision (release)	123	1,527	(3,506)
Ending Balance	9,522	9,547	9,013
Ending balance: Individually evaluated for impairment		246
Ending balance: Collectively evaluated for impairment	9,522	9,301	9,013
Loans:
Ending balance	750,991	736,247	605,721
Ending balance: Individually evaluated for impairment	3,041	6,448	5,396
Ending balance: Collectively evaluated for impairment	747,950	729,799	600,325
Real estate - residential
Allowance for loan losses:
Beginning Balance	2,692	1,694	1,981
Charge-offs	1,347	1,072	1,639
Recoveries	980	1,331	1,075
Provision (release)	(520)	739	277
Ending Balance	1,805	2,692	1,694
Ending balance: Individually evaluated for impairment	53	803	31
Ending balance: Collectively evaluated for impairment	1,752	1,889	1,663
Loans:
Ending balance	426,230	377,851	351,007
Ending balance: Individually evaluated for impairment	14,575	14,952	15,334
Ending balance: Collectively evaluated for impairment	411,655	362,899	335,673
Consumer
Allowance for loan losses:
Beginning Balance	833	1,190	1,454
Charge-offs	386	344	483
Recoveries	243	253	359
Provision (release)	834	(266)	(140)
Ending Balance	1,524	833	1,190
Ending balance: Individually evaluated for impairment	91
Ending balance: Collectively evaluated for impairment	1,433	833	1,190
Loans:
Ending balance	2,774	3,237	4,216
Ending balance: Individually evaluated for impairment	2,117
Ending balance: Collectively evaluated for impairment	657	3,237	4,216
All other
Allowance for loan losses:
Beginning Balance	435	1,965	2,506
Charge-offs	1
Recoveries	18	18
Provision (release)	90	(1,548)	(541)
Ending Balance	542	435	1,965
Ending balance: Collectively evaluated for impairment	542	435	1,965
Loans:
Ending balance	11,289	13,190	11,650
Ending balance: Collectively evaluated for impairment	11,289	13,190	11,650
Construction Loans
Allowance for loan losses:
Beginning Balance	389	265	1,475
Charge-offs	23	23	2
Recoveries	377	96	276
Provision (release)	180	51	(1,484)
Ending Balance	923	389	265
Ending balance: Collectively evaluated for impairment	923	389	265
Loans:
Ending balance	85,162	64,720	19,806
Ending balance: Individually evaluated for impairment	201	281	83
Ending balance: Collectively evaluated for impairment	$ 84,961	$ 64,439	$ 19,723

Other Real Estate Owned (Detail

Other Real Estate Owned (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Activity in the other real estate owned (OREO) portfolio, net of valuation reserve
Balance at beginning of period	$ 11,916	$ 19,141	$ 31,982
Property additions	3,796	1,785	8,998
Property improvements		16
Less: Property disposals, net of gains/losses	5,633	7,456	17,763
Less: Period valuation adjustments	1,708	1,570	4,076
Balance at end of period	8,371	11,916	19,141
Activity in the valuation allowance
Balance at beginning of period	9,982	14,127	19,229
Provision for unrealized losses	1,708	1,570	4,076
Reductions taken on sales	(3,482)	(5,867)	(9,271)
Other adjustments		152	93
Balance at end of period	8,208	9,982	14,127
Expenses related to foreclosed assets, net of lease revenue
Gain on sales, net	(474)	(374)	(1,073)
Provision for unrealized losses	1,708	1,570	4,076
Operating expenses	1,227	1,765	2,888
Less: Lease revenue	296	218	700
Expenses related to OREO, net of lease revenue	$ 2,165	$ 2,743	$ 5,191

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Premises and equipment
Cost	$ 100,689	$ 100,581
Accumulated Depreciation/Amortization	63,061	61,604
Net Book Value	37,628	38,977
Land
Premises and equipment
Cost	16,124	16,141
Net Book Value	16,124	16,141
Buildings
Premises and equipment
Cost	41,499	41,409
Accumulated Depreciation/Amortization	22,935	21,966
Net Book Value	18,564	19,443
Leasehold improvements
Premises and equipment
Cost	156	156
Accumulated Depreciation/Amortization	144	86
Net Book Value	12	70
Furniture and equipment
Premises and equipment
Cost	42,910	42,875
Accumulated Depreciation/Amortization	39,982	39,552
Net Book Value	$ 2,928	$ 3,323

Deposits - Components and Matur

Deposits - Components and Maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Deposits
Noninterest bearing demand	$ 572,404	$ 513,688
Savings	262,220	256,159
NOW accounts	429,448	419,417
Money market accounts	276,082	275,273
Certificates of deposit of less than $100,000	216,493	228,993
Certificates of deposit of $100,000 up to $250,000	122,489	110,992
Certificates of deposit of $250,000 or more	43,789	62,263
Total deposits	$ 1,922,925	$ 1,866,785

Deposits - Scheduled maturities

Deposits - Scheduled maturities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Oct. 28, 2016
Brokered certificates
Brokered certificates of deposit	$ 18,800	$ 5,900
Deposits held by senior officers and directors, including their related interests	2,600	1,600
Time Deposit Maturities
2,018	158,547
2,019	101,609
2,020	84,951
2,021	32,271
2,022	5,393
Total	382,771	$ 402,248
Talmer
Deposits	$ 48,900		$ 48,900

Borrowings - Summary (Details)

Borrowings - Summary (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Borrowings
Senior Notes	$ 44,058	$ 43,998
Total borrowings	246,615	197,304
Securities sold under repurchase agreements
Borrowings
Total borrowings	29,918	25,715
FHLBC advances
Borrowings
Total borrowings	115,000	70,000
Junior subordinated debentures
Borrowings
Total borrowings	57,639	57,591
Senior Notes.
Borrowings
Total borrowings	$ 44,058	$ 43,998

Borrowings - Additional informa

Borrowings - Additional information (Details)	12 Months Ended
	Dec. 31, 2017USD ($)item	Dec. 31, 2016USD ($)
Borrowings
Threshold percentage of stockholders' equity	10.00%
Borrowings at FHLBC as percentage of total assets	35.00%
Bank owned FHLBC stock	$ 5,400,000	$ 3,100,000
Fair value of securities collateralized	80,900,000
Principal balance of loans collateralized	277,400,000
Maximum borrowing capacity	286,300,000
Amount available for additional borrowings	132,000,000
Senior notes	44,058,000	43,998,000
Debt issuance costs	739,000	787,000
Total borrowings	246,615,000	197,304,000
Securities sold under repurchase agreements
Borrowings
Carrying amount of securities secured	29,900,000	25,700,000
Fair value of the pledged collateral	$ 40,000,000	43,000,000
Number of customers having secured balances exceeding specified percentage of stockholders equity | item	0
Total borrowings	$ 29,918,000	$ 25,715,000
Securities sold under repurchase agreements | Minimum
Borrowings
Maturity	1 day
Securities sold under repurchase agreements | Maximum
Borrowings
Maturity	90 days
FHLBC advances
Borrowings
Semi annual interest rate		0.70%
FHLBC advance amount	$ 115,000,000
Total borrowings	$ 115,000,000	$ 70,000,000
FHLB advances at 1.42 %
Borrowings
Semi annual interest rate	1.42%
FHLBC advance amount	$ 110,000,000
FHLB advances at 1.44 %
Borrowings
Semi annual interest rate	1.44%
FHLBC advance amount	$ 5,000,000
Junior subordinated debentures
Borrowings
Total borrowings	$ 57,639,000	57,591,000
Senior Notes.
Borrowings
Semi annual interest rate	5.75%
Debt Instrument, Term	10 years
Interest rate term	5 years
Debt issuance costs	$ 942,000	1,000,000
Total borrowings	$ 44,058,000	$ 43,998,000
Senior Notes. | Three month LIBOR
Borrowings
Basis points added to reference rate (as a percent)	385.00%

Borrowings - Maturities and Wei

Borrowings - Maturities and Weighted Average Rates (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Scheduled maturities and weighted average rates of borrowings
Year one	$ 144,918	$ 95,715
Thereafter	101,697	101,589
Total	$ 246,615	$ 197,304
Weighted Average Rate
Year one (as a percent)	0.86%	0.51%
Thereafter (as a percent)	6.01%	6.65%
Total (as a percent)	2.98%	3.67%

Junior Subordinated Debentures

Junior Subordinated Debentures - Issuance (Details) - USD ($) $ in Thousands	1 Months Ended			6 Months Ended	7 Months Ended	12 Months Ended
	Apr. 30, 2007	Jul. 31, 2003	Jun. 30, 2003	Jun. 15, 2017	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Junior subordinated debentures
Junior subordinated debentures					$ 57,639	$ 57,639	$ 57,591
Junior Subordinated Debentures issuance cost					$ 739	$ 739	$ 787
Old Second Capital Trust I
Junior subordinated debentures
Proceeds from sale of cumulative trust preferred securities		$ 4,100	$ 27,500
Maturity Period						30 years
Cash distribution rate of trust preferred securities (as a percent)						7.80%
Amortization period						30 years
Old Second Capital Trust II
Junior subordinated debentures
Proceeds from sale of cumulative trust preferred securities	$ 25,000
Maturity Period						30 years
Cash distribution fixed rate of trust preferred securities (as a percent)				6.77%	3.09%	4.30%
Basis points added to cash distribution floating rate base (as a percent)					1.50%
Cash distribution, floating rate base						three-month LIBOR
Junior subordinated debentures | Old Second Capital Trust I
Junior subordinated debentures
Junior subordinated debentures					$ 32,600	$ 32,600
Junior subordinated debentures | Old Second Capital Trust II
Junior subordinated debentures
Junior subordinated debentures					$ 25,800	$ 25,800

Junior Subordinated Debenture78

Junior Subordinated Debentures - Payments and other disclosures (Details)	12 Months Ended
	Dec. 31, 2017item
Junior subordinated debentures
Junior subordinated debentures
Period of interest payments that may be deferred (in quarters)	20

Income Taxes - Components (Deta

Income Taxes - Components (Details) - USD ($) $ in Thousands	Jan. 01, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of income tax expense (benefit)
Current federal		$ (2,407)	$ 399	$ 220
Deferred federal		11,724	6,824	7,023
Deferred state		372	1,597	1,733
Expense due to enactment of federal tax reform		9,475
Provision for income taxes		19,164	8,820	$ 8,976
Deferred tax assets
Allowance for loan losses		5,377	7,057
Deferred compensation		650	735
Amortization of core deposit		827	1,401
Goodwill amortization/impairment		6,087	10,127
Stock option expense		866	946
OREO write downs		2,385	5,110
Federal net operating loss ("NOL") carryforward		7,240	19,362
State net operating loss ("NOL") carryforward		7,020	7,735
Deferred tax credit			2,058
Other assets		1,017	1,199
Total deferred tax assets		31,469	55,730
Deferred tax liabilities
Accumulated depreciation on premises and equipment		(384)	(681)
Mortgage servicing rights		(2,086)	(2,760)
State tax benefits		(2,389)	(4,127)
Other liabilities		(545)	(526)
Total deferred tax liabilities		(5,404)	(8,094)
Net deferred tax asset before valuation allowance		26,065	47,636
Tax effect of adjustments related to other comprehensive loss		(709)	5,828
Net deferred tax asset		$ 25,356	$ 53,464
Corporate federal tax rate		35.00%
Forecast
Deferred tax liabilities
Corporate federal tax rate	21.00%

Income Taxes - Carryforwards (D

Income Taxes - Carryforwards (Details) $ in Millions	Dec. 31, 2017USD ($)
Alternative minimum tax credit
Net operating loss carryforward
Alternative minimum tax credit that can be carried forward	$ 2.6
Federal
Net operating loss carryforward
Net operating loss carryforward	34.5
Federal | 2030
Net operating loss carryforward
Net operating loss carryforward	10.6
Federal | 2031
Net operating loss carryforward
Net operating loss carryforward	8.6
Federal | 2032
Net operating loss carryforward
Net operating loss carryforward	15.3
State
Net operating loss carryforward
Net operating loss carryforward	74.1
State | 2021
Net operating loss carryforward
Net operating loss carryforward	$ 73.6

Income Taxes - Components of De

Income Taxes - Components of Deferred Income Tax Provision (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Components of the provision for deferred income taxes
Provision for loan losses	$ 1,680	$ 42	$ 2,480
Deferred compensation	85	(45)	97
Amortization of core deposit intangible assets	574	228	230
Stock option expense	80	(132)	(151)
OREO write downs	2,725	1,807	1,722
Federal net operating loss carryforward	12,122	4,743	2,896
State net operating loss carryforward	715	1,011	659
Deferred tax credit	2,058	(309)	(198)
Depreciation	(297)	80	(201)
Mortgage servicing rights	(674)	276	164
Goodwill amortization/impairment	4,040	1,496	1,506
State tax benefits	(1,738)	(559)	(604)
Other, net	201	(217)	156
Total deferred tax benefit	21,571	8,421	8,756
Difference between effective tax rates and federal statutory rates applied to financial statement income
Tax at statutory federal income tax rate	11,817	8,577	8,526
Nontaxable interest income, net of disallowed interest deduction	(1,976)	(347)	(253)
BOLI Income	(501)	(449)	(487)
Impact of Federal tax rate change	9,475
State income taxes, net of federal benefit	1,775	1,148	1,126
Impact of Illinois tax rate change	(1,566)
Other, net	140	(109)	64
Provision for income taxes	19,164	8,820	8,976
Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest	$ 34,302	$ 24,504	$ 24,361

Equity Compensation Plans - Opt

Equity Compensation Plans - Options (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2009	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 31, 2016
Equity Compensation Plans
Term of stock options granted	10 years
Vesting period	3 years
Exercised (in shares)				1,500
2009 Plan
Equity Compensation Plans
Granted (in shares)		16,500
Shares
Ending outstanding (in shares)	9,000		9,000
Stock options
Equity Compensation Plans
Total unrecognized compensation cost	$ 0		$ 0
Shares
Beginning outstanding (in shares)			94,500
Canceled (in shares)			(44,500)
Expired (in shares)			(41,000)
Ending outstanding (in shares)	9,000		9,000	94,500
Exercised (in dollars)				$ 2,790,000
Ending outstanding (in dollars)	$ 55,440,000		$ 55,440,000
Exercisable at the end of the period (in dollars)	$ 55,440,000		$ 55,440,000
Exercisable at end of period (in shares)	9,000		9,000
Weighted Average Exercise Price
Beginning outstanding (in dollars per share)			$ 25.82
Canceled (in dollars per share)			27.75
Expired (in dollars per share)			27.75
Ending outstanding (in dollars per share)	$ 7.49		7.49	$ 25.82
Exercisable at end of period (in dollars per share)	$ 7.49		$ 7.49
Weighted Average Remaining Contractual Term (years)
Ending outstanding (in years)			1 year 1 month 6 days
Exercisable at end of period			1 year 1 month 6 days
Stock options | 2014 Plan
Equity Compensation Plans
Number of shares authorized					375,000	975,000
Stock options | 2009 Plan
Equity Compensation Plans
Exercised (in shares)			0		0

Equity Compensation Plans - Sum

Equity Compensation Plans - Summary of stock option activity (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	May 31, 2016
Summary Of Stock Option Activity [Abstract]
Cash received from options exercised		$ 11,000
Stock based compensation	$ 1,181,000	657,000	$ 613,000
Stock options
Summary Of Stock Option Activity [Abstract]
Intrinsic value of options exercised		2,790,000
Cash received from options exercised		11,235,000
Tax benefit realized from option exercises		$ 91,000
Stock options | 2014 Plan
Summary Of Stock Option Activity [Abstract]
Number of shares authorized			375,000	975,000
Number of additional shares authorised in amendment				600,000
Number of shares issuable	453,209

Equity Compensation Plans - Res

Equity Compensation Plans - Restricted Stock and RSUs (Details) - USD ($) $ / shares in Units, $ in Millions	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016
Equity Compensation Plans
Vesting period	3 years
Restricted stock and restricted stock units
Changes in unvested awards
Nonvested at the beginning of the period (in shares)		409,000
Granted (in shares)		161,500	170,000
Vested (in shares)		(91,500)
Forfeited (in shares)		(14,000)
Nonvested at the end of the period (in shares)	465,000	465,000	409,000
Weighted Average Grant Date Fair Value
Nonvested at the beginning of the period (in dollars per share)		$ 5.89
Granted (in dollars per share)		11.04
Vested (in dollars per share)		5.07
Forfeited (in dollars per share)		7.53
Nonvested at the end of the period (in dollars per share)	$ 7.79	$ 7.79	$ 5.89
Additional information
Total unrecognized compensation cost of restricted awards	$ 1.7	$ 1.7
Expected weighted-average period for recognition of unrecognized compensation		2 years 2 months 1 day

Earnings Per Share - Reconcilia

Earnings Per Share - Reconciliation (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended			36 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017
Basic earnings per share:
Weighted-average common shares outstanding	29,600,702	29,532,510	29,476,821
Net income	$ 15,138	$ 15,684	$ 15,385
Preferred stock dividends and accretion			1,873
Preferred stock dividends and accretion of discount			1,873
Net income available to common stockholders	$ 15,138	$ 15,684	$ 13,512
Basic earnings per share (in dollars per share)	$ 0.51	$ 0.53	$ 0.46
Diluted earnings per share:
Weighted-average common shares outstanding	29,600,702	29,532,510	29,476,821
Diluted average common shares outstanding	30,038,417	29,838,931	29,730,074
Net earnings available to common stockholders	$ 15,138	$ 15,684	$ 13,512
Diluted earnings per share (in dollars per share)	$ 0.50	$ 0.53	$ 0.46
One 10 year warrant	815,339	900,839	977,839
Warrants
Diluted earnings per share:
One 10 year warrant				815,339
Warrants, exercise price (in dollars per share)	$ 13.43			$ 13.43
Restricted stock and restricted stock units
Diluted earnings per share:
Dilutive effect of nonvested restricted awards (in shares)	435,142	305,678	253,253
Stock options
Diluted earnings per share:
Dilutive effect of nonvested restricted awards (in shares)	2,573	743

Commitments - Summary of Financ

Commitments - Summary of Financial Instrument Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Fixed
Financial instrument commitments
Financial instrument commitments	$ 418	$ 315
Loan commitments	82,942	68,996
Fixed | Borrower
Financial instrument commitments
Financial instrument commitments	418	220
Fixed | Borrower | Financial standby
Financial instrument commitments
Financial instrument commitments	177	137
Fixed | Borrower | Performance standby
Financial instrument commitments
Financial instrument commitments	241	83
Fixed | Nonborrower | Performance standby
Financial instrument commitments
Financial instrument commitments		95
Variable
Financial instrument commitments
Financial instrument commitments	11,860	13,196
Loan commitments	260,061	270,989
Variable | Borrower
Financial instrument commitments
Financial instrument commitments	11,718	12,672
Variable | Borrower | Financial standby
Financial instrument commitments
Financial instrument commitments	3,770	4,047
Variable | Borrower | Commercial standby
Financial instrument commitments
Financial instrument commitments	354	126
Variable | Borrower | Performance standby
Financial instrument commitments
Financial instrument commitments	7,594	8,499
Variable | Nonborrower | Performance standby
Financial instrument commitments
Financial instrument commitments	142	524
Total.
Financial instrument commitments
Financial instrument commitments	12,278	13,511
Loan commitments	343,003	339,985
Total. | Borrower
Financial instrument commitments
Financial instrument commitments	12,136	12,892
Total. | Borrower | Financial standby
Financial instrument commitments
Financial instrument commitments	3,947	4,184
Total. | Borrower | Commercial standby
Financial instrument commitments
Financial instrument commitments	354	126
Total. | Borrower | Performance standby
Financial instrument commitments
Financial instrument commitments	7,835	8,582
Total. | Nonborrower | Performance standby
Financial instrument commitments
Financial instrument commitments	$ 142	$ 619

Commitments - Lease Commitments

Commitments - Lease Commitments and Legal Proceedings (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Estimated aggregate minimum annual rental commitments
2,018	$ 380,000
2,019	45,000
2,020	20,000
2021 and beyond	6,000
Aggregate future minimum rental income receivable under noncancelable leases	232,000
Total facility net operating lease revenue/expense	64,000	$ 25,000	$ 11,000
Total ATM lease expense	$ 679,000	$ 685,000	$ 826,000

Regulatory & Capital Matters (D

Regulatory & Capital Matters (Details)	Dec. 31, 2017	Dec. 31, 2016
Regulatory & Capital Matters
Tier 1 capital leverage ratio (as a percent)	10.08%	8.90%
Risk-based capital ratio (as a percent)	12.93%	12.29%
Old Second National Bank
Regulatory & Capital Matters
Tier 1 capital leverage ratio (as a percent)	10.79%	10.24%
Risk-based capital ratio (as a percent)	13.78%	13.45%
Minimum | Old Second National Bank
Regulatory & Capital Matters
Tier 1 capital leverage ratio (as a percent)	8.00%
Risk-based capital ratio (as a percent)	12.00%

Regulatory & Capital Matters -

Regulatory & Capital Matters - Capital Levels and Industry Defined Regulatory Minimums (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Common equity tier 1 capital to risk weighted assets
Actual	$ 179,853	$ 154,537
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	$ 111,801	$ 90,411
Common equity tier 1 capital to risk weighted assets, Ratio
Actual (as a percent)	9.25%	8.76%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	5.75%	5.125%
Minimum Required to Be Well Capitalized (as a percent)		6.50%
Total capital to risk weighted assets, Amount
Actual at period end	$ 251,383	$ 216,769
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	$ 179,837	$ 152,126
Total capital to risk weighted assets, Ratio
Risk-based capital ratio (as a percent)	12.93%	12.29%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	9.25%	8.625%
Tier 1 capital to risk weighted assets, Amount
Actual	$ 233,927	$ 191,988
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	$ 140,978	$ 116,904
Tier 1 capital to risk weighted assets, Ratio
Actual (as a percent)	12.03%	10.88%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	7.25%	6.625%
Tier 1 capital to average assets, Amount
Actual	$ 233,927	$ 191,988
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	$ 92,828	$ 86,287
Tier 1 capital to average assets, Ratio
Tier 1 capital leverage ratio (as a percent)	10.08%	8.90%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	4.00%	4.00%
Old Second National Bank
Common equity tier 1 capital to risk weighted assets
Actual	$ 249,417	$ 221,153
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	111,347	90,456
Minimum Required to Be Well Capitalized	$ 125,870	$ 114,724
Common equity tier 1 capital to risk weighted assets, Ratio
Actual (as a percent)	12.88%	12.53%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	5.75%
Minimum Required to Be Well Capitalized (as a percent)	6.50%
Total capital to risk weighted assets, Amount
Actual at period end	$ 266,873	$ 237,306
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	179,142	152,176
Minimum Required to Be Well Capitalized	$ 193,667	$ 176,436
Total capital to risk weighted assets, Ratio
Risk-based capital ratio (as a percent)	13.78%	13.45%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	9.25%	8.625%
Minimum Required to Be Well Capitalized (as a percent)	10.00%	10.00%
Tier 1 capital to risk weighted assets, Amount
Actual	$ 249,417	$ 221,153
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	140,394	116,930
Minimum Required to Be Well Capitalized	$ 154,917	$ 141,199
Tier 1 capital to risk weighted assets, Ratio
Actual (as a percent)	12.88%	12.53%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	7.25%	6.625%
Minimum Required to Be Well Capitalized (as a percent)	8.00%	8.00%
Tier 1 capital to average assets, Amount
Actual	$ 249,417	$ 221,153
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable	92,462	86,388
Minimum Required to Be Well Capitalized	$ 115,578	$ 107,985
Tier 1 capital to average assets, Ratio
Tier 1 capital leverage ratio (as a percent)	10.79%	10.24%
Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)	4.00%	4.00%
Minimum Required to Be Well Capitalized (as a percent)	5.00%	5.00%

Regulatory & Capital Matters 90

Regulatory & Capital Matters - Dividend Restrictions and Deferrals (Details)	12 Months Ended
	Dec. 31, 2017
Dividend Restrictions and Deferrals
Number of previous years retained profit considered for dividend payment	2 years
Minimum capital requirements, minimum percentage required, 2016	0.625%
Minimum capital requirements, minimum percentage required, 2017	1.25%
Minimum capital requirements, minimum percentage required, 2018	1.875%
Minimum capital requirements, minimum percentage required, 2019 and thereafter	2.50%

Mortgage Banking Derivatives (D

Mortgage Banking Derivatives (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Mortgage Banking Derivatives
Amount of loans sold to investors	$ 147,700
Proceeds from sale of loan to investors	151,289	$ 197,654	$ 196,431
Gain on sale of loan	4,803	6,343	$ 5,775
Fair market valuation gain	1,300
Federal National Mortgage Association
Mortgage Banking Derivatives
Amount of loans sold to investors	$ 88,900
Federal National Mortgage Association | Customer concentration risk
Mortgage Banking Derivatives
Percentage of concentration risk	60.30%
Wells Fargo | Customer concentration risk
Mortgage Banking Derivatives
Percentage of concentration risk	19.60%
Federal Home Loan Mortgage Corp.
Mortgage Banking Derivatives
Amount of loans sold to investors	$ 28,900
Not designated | Forward MBS contracts and forward loan contracts
Mortgage Banking Derivatives
Notional or Contractual Amount	16,500	19,500
Fair value	3	190
Not designated | Rate Lock Commitments
Mortgage Banking Derivatives
Notional or Contractual Amount	10,478	12,480
Fair value	$ 235	$ 97

Fair Value Measurements - Recur

Fair Value Measurements - Recurring (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Assets:
Securities available-for-sale	$ 541,439	$ 531,838
Mortgage servicing rights	6,944	6,489
U.S. Treasury
Assets:
Securities available-for-sale	3,947
U.S. government agencies
Assets:
Securities available-for-sale	13,061
U.S. government agency mortgage-backed
Assets:
Securities available-for-sale	12,214
States and political subdivisions
Assets and liabilities measured at fair value on a recurring basis
Purchases	16,712	14,296
Assets:
Securities available-for-sale	278,092	68,703
Corporate bonds
Assets:
Securities available-for-sale	833	10,630
Collateralized mortgage obligations
Assets:
Securities available-for-sale	65,939	170,927
Asset-backed securities
Assets:
Securities available-for-sale	112,932	138,407
Collateralized loan obligations
Assets:
Securities available-for-sale	54,421	101,637
Level 1
Assets:
Securities available-for-sale	3,947
Level 1 | U.S. Treasury
Assets:
Securities available-for-sale	3,947
Level 2
Assets:
Securities available-for-sale	520,963	506,493
Loans held-for-sale	4,067	4,918
Liabilities:
Other liabilities	1,287
Level 2 | Interest rate swap agreements net of swap credit valuation
Liabilities:
Other liabilities		994
Level 2 | U.S. government agencies
Assets:
Securities available-for-sale	13,061
Level 2 | U.S. government agency mortgage-backed
Assets:
Securities available-for-sale	12,214
Level 3
Assets:
Securities available-for-sale	16,529	25,345
Recurring
Assets:
Securities available-for-sale		41,534
Loans held-for-sale	4,067	4,918
Mortgage servicing rights	6,944	6,489
Total financial assets	553,415	544,205
Liabilities:
Total	2,014	1,667
Recurring | Interest rate swap agreements net of swap credit valuation
Assets:
Other assets	727	673
Liabilities:
Other liabilities	2,014	1,667
Recurring | Forward MBS contracts and forward loan contracts
Assets:
Other assets	238	287
Recurring | States and political subdivisions
Assets:
Securities available-for-sale	278,092	68,703
Recurring | Corporate bonds
Assets:
Securities available-for-sale	833	10,630
Recurring | Collateralized mortgage obligations
Assets:
Securities available-for-sale	65,939	170,927
Recurring | Asset-backed securities
Assets:
Securities available-for-sale	112,932	138,407
Recurring | Collateralized loan obligations
Assets:
Securities available-for-sale	54,421	101,637
Recurring | Level 1
Assets:
Total financial assets	3,947
Recurring | Level 2
Assets:
Securities available-for-sale		41,534
Loans held-for-sale	4,067	4,918
Total financial assets	525,995	512,371
Liabilities:
Total	2,014	1,667
Recurring | Level 2 | Interest rate swap agreements net of swap credit valuation
Assets:
Other assets	727	673
Liabilities:
Other liabilities	2,014	1,667
Recurring | Level 2 | Forward MBS contracts and forward loan contracts
Assets:
Other assets	238	287
Recurring | Level 2 | States and political subdivisions
Assets:
Securities available-for-sale	263,831	46,477
Recurring | Level 2 | Corporate bonds
Assets:
Securities available-for-sale	833	10,630
Recurring | Level 2 | Collateralized mortgage obligations
Assets:
Securities available-for-sale	63,671	167,808
Recurring | Level 2 | Asset-backed securities
Assets:
Securities available-for-sale	112,932	138,407
Recurring | Level 2 | Collateralized loan obligations
Assets:
Securities available-for-sale	54,421	101,637
Recurring | Level 3
Assets:
Mortgage servicing rights	6,944	6,489
Total financial assets	23,473	31,834
Recurring | Level 3 | States and political subdivisions
Assets:
Securities available-for-sale	14,261	22,226
Recurring | Level 3 | Collateralized mortgage obligations
Assets:
Securities available-for-sale	$ 2,268	$ 3,119

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Changes in Level 3
Beginning balance	$ 3,119
Total gains or losses
Included in earnings (or changes in net assets)	40
Included in other comprehensive income	21	$ (82)
Purchases, issuances, sales, and settlements
Settlements	(912)
Ending balance		3,119
Changes in Level 3 (liabilities)
Beginning balance	(3,119)
Ending balance	2,268	3,119
Collateralized loan obligations
Purchases, issuances, sales, and settlements
Transfers into Level 3		3,201
States and political subdivisions
Changes in Level 3
Beginning balance	22,226	111
Total gains or losses
Included in other comprehensive income	(796)	87
Purchases, issuances, sales, and settlements
Purchases	16,712	14,296
Settlements	(23,881)	(81)
Ending balance	14,261	22,226
Transfers into Level 3		7,813
Mortgage servicing rights
Changes in Level 3
Beginning balance	6,489	5,847
Total gains or losses
Included in earnings (or changes in net assets)	(270)	(215)
Purchases, issuances, sales, and settlements
Issuances	1,257	1,561
Settlements	(532)	(704)
Ending balance	$ 6,944	$ 6,489

Fair Value Measurements - Quant

Fair Value Measurements - Quantitative and Qualitative Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Quantitative information about Level 3 fair value measurements
Mortgage servicing rights, fair value	$ 6,944	$ 6,489
Minimum
Quantitative information about Level 3 fair value measurements
Discount rate (as a percent)	10.00%	10.00%
Maximum
Quantitative information about Level 3 fair value measurements
Discount rate (as a percent)		17.00%
Prepayment speed (as a percent)	34.30%
Weighted Average
Quantitative information about Level 3 fair value measurements
Discount rate (as a percent)	10.20%	10.20%
Mortgage servicing rights
Quantitative information about Level 3 fair value measurements
Mortgage servicing rights, fair value		$ 6,489
Recurring
Quantitative information about Level 3 fair value measurements
Mortgage servicing rights, fair value	$ 6,944	6,489
Recurring | Level 3
Quantitative information about Level 3 fair value measurements
Mortgage servicing rights, fair value	$ 6,944	$ 6,489
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 | Minimum
Quantitative information about Level 3 fair value measurements
Discount rate (as a percent)		6.50%
Prepayment speed (as a percent)	7.00%
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 | Maximum
Quantitative information about Level 3 fair value measurements
Discount rate (as a percent)		77.80%
Prepayment speed (as a percent)	68.40%
Recurring | Mortgage servicing rights | Discounted Cash Flow | Level 3 | Weighted Average
Quantitative information about Level 3 fair value measurements
Discount rate (as a percent)		9.60%
Prepayment speed (as a percent)	9.60%

Fair Value Measurements - Nonre

Fair Value Measurements - Nonrecurring (Details) - USD ($)	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets and liabilities measured at fair value
Valuation allowance	$ 144,000	$ 1,049,000
Increase (decrease) of specific allocations within the provision for loan losses	856,000
Carrying value of other real estate owned	8,371,000	11,916,000	$ 19,141,000	$ 31,982,000
Outstanding balance		23,500,000
OREO Valuation allowance	8,208,000	9,982,000	$ 14,127,000	$ 19,229,000
Impaired loans
Assets and liabilities measured at fair value
Valuation allowance	5,300,000
Nonrecurring
Assets and liabilities measured at fair value
Total	13,484,000	11,916,000
Nonrecurring | Impaired loans
Assets and liabilities measured at fair value
Total	5,113,000
Increase (decrease) of specific allocations within the provision for loan losses		(1)
Nonrecurring | Impaired loans | Carrying Amount
Assets and liabilities measured at fair value
Total		1,000,000
Nonrecurring | Other real estate owned
Assets and liabilities measured at fair value
Total	8,371,000	11,916,000
Outstanding balance	17,400,000
OREO Valuation allowance	8,200,000	14,100,000
OREO participations	900,000,000,000	1,700,000
Nonrecurring | Level 3
Assets and liabilities measured at fair value
Total	13,484,000	11,916,000
Nonrecurring | Level 3 | Impaired loans
Assets and liabilities measured at fair value
Total	5,113,000
Nonrecurring | Level 3 | Other real estate owned
Assets and liabilities measured at fair value
Total	$ 8,371,000	$ 11,916,000

Fair Values of Financial Inst96

Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Financial assets:
Cash and due from banks	$ 37,444	$ 33,805
Interest bearing deposits with financial institutions	18,389	13,529
Securities available-for-sale	541,439	531,838
FHLBC and FRBC Stock	10,168	7,918
Bank-owned life insurance	61,764	60,332
Financial liabilities:
Noninterest bearing deposits	572,404	513,688
Other short-term borrowings	115,000	70,000
Junior subordinated debentures	57,639	57,591
Carrying Amount
Financial assets:
Cash and due from banks	37,444	33,805
Interest bearing deposits with financial institutions	18,389	13,529
Securities available-for-sale	541,439	531,838
FHLBC and FRBC Stock	10,168	7,918
Loans held for sale	4,067	4,918
Loans, net	1,600,161	1,462,651
Accrued interest receivable	8,595	5,928
Financial liabilities:
Noninterest bearing deposits	572,404	513,688
Interest bearing deposits	1,350,521	1,353,097
Securities sold under repurchase agreements	29,918	25,715
Other short-term borrowings	115,000	70,000
Junior subordinated debentures	57,639	57,591
Subordinated debenture	44,058	43,998
Interest rate swap	1,287
Borrowing interest payable	140	202
Deposit interest payable	631	599
Total Fair Value
Financial assets:
Cash and due from banks	37,444	33,805
Interest bearing deposits with financial institutions	18,389	13,529
Securities available-for-sale	541,439	531,838
FHLBC and FRBC Stock	10,168	7,918
Loans held for sale	4,067	4,918
Loans, net	1,586,722	1,453,429
Accrued interest receivable	8,595	5,928
Financial liabilities:
Noninterest bearing deposits	572,404	513,688
Interest bearing deposits	1,346,339	1,351,000
Securities sold under repurchase agreements	29,918	25,715
Other short-term borrowings	115,000	70,000
Junior subordinated debentures	59,471	55,163
Subordinated debenture	46,743	43,998
Interest rate swap	1,287
Borrowing interest payable	140	202
Deposit interest payable	631	599
Level 1
Financial assets:
Cash and due from banks	37,444	33,805
Interest bearing deposits with financial institutions	18,389	13,529
Securities available-for-sale	3,947
Financial liabilities:
Noninterest bearing deposits	572,404	513,688
Junior subordinated debentures	33,267	32,404
Level 2
Financial assets:
Securities available-for-sale	520,963	506,493
FHLBC and FRBC Stock	10,168	7,918
Loans held for sale	4,067	4,918
Accrued interest receivable	8,595	5,928
Financial liabilities:
Interest bearing deposits	1,346,339	1,351,000
Securities sold under repurchase agreements	29,918	25,715
Other short-term borrowings	115,000	70,000
Junior subordinated debentures	26,204	22,759
Subordinated debenture	46,743	43,998
Interest rate swap	1,287
Borrowing interest payable	140	202
Deposit interest payable	631	599
Level 3
Financial assets:
Securities available-for-sale	16,529	25,345
Loans, net	$ 1,586,722	1,453,429
Interest rate swap agreements net of swap credit valuation | Carrying Amount
Financial liabilities:
Interest rate swap		994
Interest rate swap agreements net of swap credit valuation | Total Fair Value
Financial liabilities:
Interest rate swap		994
Interest rate swap agreements net of swap credit valuation | Level 2
Financial liabilities:
Interest rate swap		$ 994

Financial Instruments with Of97

Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions - Interest Rate Derivatives (Details)	12 Months Ended
	Dec. 31, 2017USD ($)item	Dec. 31, 2016USD ($)item
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Gain (Loss) on Cash Flow Hedge Ineffectiveness, Net	$ 0
Cash Flow Hedging [Member]
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Unrealized loss	(1,287,000)	$ (994,000)
Notional or Contractual Amount	25,774,000	25,774,000
Not designated
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Asset Derivatives, Fair Value	965,000	960,000
Liability Derivatives, Fair Value	727,000	673,000
Interest rate swap agreements net of swap credit valuation | Not designated
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Investment securities pledged with financial institutions, dollars	$ 4,200,000	$ 6,200,000
Number of correspondent financial institutions where investment securities are pledged | item	2	3
Weighted average maturity	6 years 7 months 6 days	7 years 3 months 18 days
Notional or Contractual Amount	$ 153,433,000	$ 85,807,000
Asset Derivatives, Fair Value	727,000	673,000
Liability Derivatives, Fair Value	727,000	673,000
Commitments | Not designated
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Notional or Contractual Amount	26,978,000	31,980,000
Asset Derivatives, Fair Value	238,000	287,000
Forward MBS contracts and forward loan contracts | Not designated
Financial Instruments with Off-Balance Sheet Risk and Derivative Transactions
Notional or Contractual Amount	$ 16,500,000	$ 19,500,000

Preferred Stock (Details)

Preferred Stock (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended		24 Months Ended
	Dec. 31, 2017	Dec. 31, 2015	Dec. 31, 2015	Dec. 31, 2016	Mar. 31, 2009
Preferred Stock
Dividends paid on preferred stock		$ (2,417)
Preferred stock, Shares authorized	300,000			300,000
Series B Stock
Preferred Stock
Fair value					$ 68,200
Shares redeemed (in shares)			73,000
Warrants
Preferred Stock
Warrants, term	10 years
Warrants to purchase the Company's common stock, initially authorized (in shares)	815,339
Warrants, exercise price (in dollars per share)	$ 13.43
Fair value					$ 4,800

Parent Company Condensed Fina99

Parent Company Condensed Financial Information - Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Other assets	$ 22,776	$ 16,333
Total assets	2,383,429	2,251,188
Liabilities and Stockholders' Equity
Junior subordinated debentures	57,639	57,591
Senior Notes	44,058	43,998
Other liabilities	13,539	11,889
Stockholders' equity	200,350	175,210	$ 155,929	$ 194,163
Total liabilities and stockholders' equity	2,383,429	2,251,188
Old Second Bancorp, Inc.
Assets
Noninterest bearing deposit with bank subsidiary	23,011	26,925
Investment in subsidiaries	263,389	228,646
Other assets	17,139	23,304
Total assets	303,539	278,875
Liabilities and Stockholders' Equity
Junior subordinated debentures	57,639	57,591
Senior Notes	44,058	43,998
Other liabilities	1,492	2,076
Stockholders' equity	200,350	175,210
Total liabilities and stockholders' equity	$ 303,539	$ 278,875

Parent Company Condensed Fin100

Parent Company Condensed Financial Information - Condensed Statements of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Expenses
Junior subordinated debentures interest expense	$ 4,002	$ 4,334	$ 4,287
Interest Expense Senor Notes	2,689	112
Subordinated debt interest expense		949	814
Income before income taxes	34,302	24,504	24,361
Income tax benefit	19,164	8,820	8,976
Net income	15,138	15,684	15,385
Net income available to common stockholders	15,138	15,684	13,512
Old Second Bancorp, Inc.
Operating Income
Cash dividends received from subsidiaries			82,777
Other income	114	130	131
Total operating income	114	130	82,908
Operating Expenses
Junior subordinated debentures interest expense	4,002	4,334	4,287
Interest Expense Senor Notes	2,689	112
Subordinated debt interest expense		949	814
Other interest expense		8	7
Other expenses	2,639	1,975	1,978
Total operating expense	9,330	7,378	7,086
Income before income taxes	(9,216)	(7,248)	75,822
Income tax benefit	(16)	(2,909)	(2,771)
Income (loss) before equity in undistributed net income of subsidiaries	(9,200)	(4,339)	78,593
Equity in undistributed net income of subsidiaries	24,338	20,023	(63,208)
Net income	15,138	15,684	15,385
Preferred stock dividends and accretion of discount			1,873
Net income available to common stockholders	$ 15,138	$ 15,684	$ 13,512

Parent Company Condensed Fin101

Parent Company Condensed Financial Information -Condensed Statements of Cash Flows (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Cash Flows from Operating Activities
Net income	$ 15,138,000	$ 15,684,000	$ 15,385,000
Adjustments to reconcile net income (loss) to net cash from operating activities:
Provision for deferred tax expense (benefit)	21,571,000	8,421,000	8,756,000
Net deferred tax expense due to DTA revaluation	13,662,000	8,421,000	8,756,000
Change in taxes payable	(2,519,000)	260,000	100,000
Stock-based compensation	1,181,000	657,000	613,000
Net cash provided by (used in) operating activities	37,105,000	27,256,000	21,137,000
Cash Flows from Financing Activities
Dividends paid on preferred stock			(2,417,000)
Dividends paid common stock	(1,184,000)	(888,000)
Purchases of treasury stock	(236,000)	(254,000)	(117,000)
Proceeds From Issuance Of Senior Notes		43,994,000
Payment of senior note issuance costs	(42,000)
Repayment of subordinate debt		(45,000,000)
Proceeds from (Repayments of) Notes Payable		(500,000)
Proceeds from Stock Options Exercised		11,000
Redemption of preferred stock			(47,331,000)
Net cash (used in) provided by financing activities	103,881,000	102,813,000	7,200,000
Net change in cash and cash equivalents	8,499,000	6,996,000	(3,859,000)
Cash and cash equivalents at beginning of period	47,334,000	40,338,000	44,197,000
Cash and cash equivalents at end of period	55,833,000	47,334,000	40,338,000
Old Second Bancorp, Inc.
Cash Flows from Operating Activities
Net income	15,138,000	15,684,000	15,385,000
Adjustments to reconcile net income (loss) to net cash from operating activities:
Equity in undistributed net income of subsidiaries	(24,338,000)	(20,023,000)	63,208,000
Provision for deferred tax expense (benefit)	6,397,000	(1,039,000)	(2,806,000)
Net deferred tax expense due to DTA revaluation	3,908,000
Change in taxes payable	(4,797,000)	330,000	(199,000)
Change in other assets	74,000	171,000	36,000
Stock-based compensation	1,181,000	657,000	613,000
Other, net	(15,000)	282,000	69,000
Net cash provided by (used in) operating activities	(2,452,000)	(3,938,000)	76,306,000
Cash Flows from Financing Activities
Dividends paid on preferred stock			(2,417,000)
Dividends paid common stock	(1,184,000)	(888,000)
Purchases of treasury stock	(236,000)	(254,000)	(117,000)
Proceeds From Issuance Of Senior Notes		43,994,000
Payment of senior note issuance costs	(42,000)
Repayment of subordinate debt		(45,000,000)
Proceeds from (Repayments of) Notes Payable		(500,000)
Proceeds from Stock Options Exercised		11,000
Redemption of preferred stock			(47,331,000)
Net cash (used in) provided by financing activities	(1,462,000)	(2,637,000)	(49,865,000)
Net change in cash and cash equivalents	(3,914,000)	(6,575,000)	26,441,000
Cash and cash equivalents at beginning of period	26,925,000	33,500,000	7,059,000
Cash and cash equivalents at end of period	$ 23,011,000	$ 26,925,000	$ 33,500,000

Employee Benefit Plans (Details

Employee Benefit Plans (Details) - USD ($) $ in Thousands	12 Months Ended			24 Months Ended	36 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2017	Dec. 31, 2017
Employee Benefit Plans
Company obligations under Voluntary Deferred Compensation Plan for Executives	$ 1,700	$ 1,600	$ 1,900	$ 1,700	$ 1,700
Old Second Bancorp Inc Employees 401(k) Savings Plan and Trust
Employee Benefit Plans
Company's discretionary matching contributions to the Plan (as a percent)				100.00%
Percentage of compensation contributed to the Plan matched by employer				3.00%
Participants vesting as percentage of discretionary matching contributions					100.00%
Expense relating to the 401(k) plan	$ 698	$ 464	$ 477