Byline Bancorp (BY) 10-Q 8 May 19 2019 Q1 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	3 Months Ended
	Mar. 31, 2019	May 08, 2019
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q1
Trading Symbol	BY
Entity Registrant Name	Byline Bancorp, Inc.
Entity Central Index Key	0001702750
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		38,014,042

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 50,026	$ 30,190
Interest bearing deposits with other banks	31,971	91,670
Cash and cash equivalents	81,997	121,860
Equity and other securities, at fair value	7,216
Securities available-for-sale, at fair value	964,553	817,656
Securities held-to-maturity, at amortized cost (fair value at March 31, 2019—$4,431, December 31, 2018—$97,739)	4,425	99,266
Restricted stock, at cost	19,202	19,202
Loans held for sale	510	19,827
Loans and leases:
Loans and leases	3,567,566	3,501,626
Allowance for loan and lease losses	(27,106)	(25,201)
Net loans and leases	3,540,460	3,476,425
Servicing assets, at fair value	19,534	19,693
Accrued interest receivable	11,974	10,863
Premises and equipment, net	97,069	97,680
Assets held for sale	13,596	14,489
Other real estate owned, net	4,799	5,314
Goodwill	128,177	128,177
Other intangible assets, net	31,646	33,419
Bank-owned life insurance	6,087	5,961
Deferred tax assets, net	30,534	35,643
Due from counterparty	20,691	5,338
Other assets	27,455	31,761
Total assets	5,009,925	4,942,574
LIABILITIES
Non-interest-bearing demand deposits	1,163,255	1,192,873
Interest-bearing deposits:
NOW, savings accounts, and money market accounts	1,385,551	1,413,158
Time deposits	1,259,710	1,143,885
Total deposits	3,808,516	3,749,916
Accrued interest payable	4,390	3,484
Federal Home Loan Bank advances	425,000	425,000
Securities sold under agreements to repurchase	34,369	34,166
Junior subordinated debentures issued to capital trusts, net	36,912	36,768
Accrued expenses and other liabilities	31,989	42,568
Total liabilities	4,341,176	4,291,902
STOCKHOLDERS’ EQUITY
Preferred stock	10,438	10,438
Common stock, voting, $0.01 par value at March 31, 2019 and December 31, 2018; 150,000,000 shares authorized at March 31, 2019 and December 31, 2018; 36,398,144 shares issued and outstanding at March 31, 2019 and 36,343,239 issued and outstanding at December 31, 2018	362	361
Additional paid-in capital	548,005	546,849
Retained earnings	116,363	102,522
Accumulated other comprehensive loss, net of tax	(6,419)	(9,498)
Total stockholders’ equity	668,749	650,672
Total liabilities and stockholders’ equity	$ 5,009,925	$ 4,942,574

CONSOLIDATED STATEMENTS OF FI_2

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Securities held-to-maturity, fair value	$ 4,431	$ 97,739
Common stock, voting par value	$ 0.01	$ 0.01
Common stock, voting shares authorized	150,000,000	150,000,000
Common stock, voting shares issued	36,398,144	36,343,239
Common stock, voting shares outstanding	36,398,144	36,343,239

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
INTEREST AND DIVIDEND INCOME
Interest and fees on loans and leases	$ 54,383	$ 33,654
Interest on taxable securities	5,759	4,055
Interest on tax-exempt securities	343	174
Other interest and dividend income	625	259
Total interest and dividend income	61,110	38,142
INTEREST EXPENSE
Deposits	8,076	2,498
Federal Home Loan Bank advances	2,099	1,358
Subordinated debentures and other borrowings	850	591
Total interest expense	11,025	4,447
Net interest income	50,085	33,695
PROVISION FOR LOAN AND LEASE LOSSES	3,999	5,115
Net interest income after provision for loan and lease losses	46,086	28,580
NON-INTEREST INCOME
ATM and interchange fees	717	913
Change in fair value of equity securities, net	499
Net gains on sales of loans	6,233	7,476
Wealth management and trust income	595
Other non-interest income	896	859
Total non-interest income	11,988	11,123
NON-INTEREST EXPENSE
Salaries and employee benefits	22,892	18,278
Occupancy expense, net	4,280	3,755
Equipment expense	669	603
Loan and lease related expenses	1,577	1,400
Legal, audit and other professional fees	2,066	1,851
Data processing	3,273	2,301
Net loss (gain) recognized on other real estate owned and other related expenses	196	(1)
Regulatory assessments	(59)	241
Other intangible assets amortization expense	1,773	767
Advertising and promotions	709	249
Telecommunications	464	418
Other non-interest expense	2,839	1,752
Total non-interest expense	40,679	31,614
INCOME BEFORE PROVISION FOR INCOME TAXES	17,395	8,089
PROVISION FOR INCOME TAXES	4,798	1,321
NET INCOME	12,597	6,768
Dividends on preferred shares	196	193
INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 12,401	$ 6,575
EARNINGS PER COMMON SHARE
Basic	$ 0.34	$ 0.22
Diluted	$ 0.34	$ 0.22
Fees and Service Charges on Deposits [Member]
NON-INTEREST INCOME
Fees and charges	$ 1,770	$ 1,312
Loan Servicing Revenue [Member]
NON-INTEREST INCOME
Fees and charges	2,539	2,450
Loan Servicing Asset Revaluation [Member]
NON-INTEREST INCOME
Fees and charges	$ (1,261)	$ (1,887)

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 12,597	$ 6,768
Securities available-for-sale
Unrealized holding gains (losses) arising during the period	8,635	(8,852)
Tax effect	(2,296)	2,395
Net of tax	6,339	(6,457)
Cash flow hedges
Unrealized holding gains (losses) arising during the period	(1,817)	4,070
Reclassification adjustments for net gains included in net income	(705)	(61)
Tax effect	702	(1,116)
Net of tax	(1,820)	2,893
Total other comprehensive income (loss)	4,519	(3,564)
Comprehensive income	$ 17,116	$ 3,204

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2017	$ 458,578	$ 10,438	$ 292	$ 391,586	$ 61,349	$ (5,087)
Beginning balance, shares at Dec. 31, 2017		10,438	29,317,298
Net income	6,768				6,768
Other comprehensive loss, net of tax	(3,564)					(3,564)
Issuance of common stock upon exercise of stock options	1,005		$ 1	1,004
Issuance of common stock upon exercise of stock options, shares			86,750
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)	(763)				763	(763)
Cash dividends declared on preferred stock	(193)				(193)
Share-based compensation expense	342			342
Ending balance at Mar. 31, 2018	462,936	$ 10,438	$ 293	392,932	68,687	(9,414)
Ending balance, shares at Mar. 31, 2018		10,438	29,404,048
Beginning balance at Dec. 31, 2017	458,578	$ 10,438	$ 292	391,586	61,349	(5,087)
Beginning balance, shares at Dec. 31, 2017		10,438	29,317,298
Ending balance at Dec. 31, 2018	650,672	$ 10,438	$ 361	546,849	102,522	(9,498)
Ending balance, shares at Dec. 31, 2018		10,438	36,343,239
Net income	12,597				12,597
Other comprehensive loss, net of tax	4,519					4,519
Issuance of common stock upon exercise of stock options	636		$ 1	635
Issuance of common stock upon exercise of stock options, shares			50,662
Forfeiture of restricted stock awards, shares			(8,500)
Issuance of common stock in connection with employee stock purchase plan	291			291
Issuance of common stock in connection with employee stock purchase plan, shares			12,743
Cumulative-effect adjustment (ASU 2016-01) | ASU 2016-01					1,440	(1,440)
Cash dividends declared on preferred stock	(196)				(196)
Share-based compensation expense	230			230
Ending balance at Mar. 31, 2019	$ 668,749	$ 10,438	$ 362	$ 548,005	$ 116,363	$ (6,419)
Ending balance, shares at Mar. 31, 2019		10,438	36,398,144

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 12,597	$ 6,768
Adjustments to reconcile net income to net cash from operating activities:
PROVISION FOR LOAN AND LEASE LOSSES	3,999	5,115
Impairment loss on assets held for sale	392
Depreciation and amortization of premises and equipment	1,590	1,273
Change in fair value of equity securities, net	(499)
Net amortization of securities	600	1,009
Net gains on sales of assets held for sale	(13)	(189)
Net gains on sales of loans	(6,233)	(7,476)
Originations of U.S. government guaranteed loans	(47,157)	(82,125)
Proceeds from U.S. government guaranteed loans sold	55,421	104,604
Accretion of premiums and discounts on acquired loans, net	(5,201)	(2,346)
Net change in servicing assets	159	(215)
Net valuation adjustments on other real estate owned	84	81
Net losses (gains) on sales of other real estate owned	33	(140)
Other intangible assets amortization expense	1,773	767
Amortization of time deposit premium	(69)	(5)
Amortization of Federal Home Loan Bank advances premium		(19)
Accretion of junior subordinated debentures discount	144	153
Share-based compensation expense	230	342
Deferred tax provision, net of valuation	3,515	1,284
Increase in cash surrender value of bank owned life insurance	(126)	(120)
Changes in assets and liabilities:
Accrued interest receivable	(1,917)	673
Other assets	4,236	622
Accrued interest payable	906	306
Accrued expenses and other liabilities	(10,579)	(4,894)
Net cash provided by operating activities	13,885	25,468
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of securities available-for-sale	(84,950)	(72,646)
Proceeds from maturities and calls of securities available-for-sale	14,850	5,430
Proceeds from paydowns of securities available-for-sale	18,966	14,691
Proceeds from paydowns of securities held-to-maturity		4,050
Purchases of Federal Home Loan Bank stock	(9,630)	(6,282)
Federal Home Loan Bank stock repurchases	9,630	5,448
Net change in loans and leases	(62,197)	(5,797)
Purchases of premises and equipment	(979)	(63)
Proceeds from sales of assets held for sale	514	954
Proceeds from sales of other real estate owned	445	1,263
Net cash used in investing activities	(113,351)	(52,952)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	58,669	81,223
Proceeds from Federal Home Loan Bank advances	1,620,500	1,589,900
Repayments of Federal Home Loan Bank advances	(1,620,500)	(1,571,387)
Net (decrease) increase in securities sold under agreements to repurchase	203	(3,372)
Dividends paid on preferred stock	(196)	(193)
Proceeds from issuance of common stock upon exercise of stock options	636	1,005
Proceeds from issuance of common stock	291
Net cash provided by financing activities	59,603	97,176
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS	(39,863)	69,692
CASH AND CASH EQUIVALENTS, beginning of period	121,860	58,349
CASH AND CASH EQUIVALENTS, end of period	81,997	128,041
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	10,044	4,012
Cash payments (refunds) during the period for taxes	(2,556)	63
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in fair value of available-for-sale securities, net of tax	6,339	(6,457)
Change in fair value of cash flow hedges, net of tax	(1,820)	2,893
Delayed payments of mortgage-backed securities	626	726
Transfer of securities from held-to-maturity to available-for-sale	94,837
Reclassification of equity and other securities	6,609
Transfers of loans to other real estate owned	230	1,044
Internally financed sale of other real estate owned	183
Transfer of other assets to assets held for sale		16
Due from counterparties	$ 15,353	$ 19,837

Basis of Presentation

Basis of Presentation	3 Months Ended
	Mar. 31, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	These unaudited interim condensed consolidated financial statements include the accounts of Byline Illinois state chartered These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). In preparing these financial statements, the Company has evaluated events and transactions subsequent to March 31, 2019 for potential recognition or disclosure. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information in footnote disclosures normally included in financial statements prepared in accordance with GAAP has been condensed or omitted pursuant to the rules and regulations of the SEC and the accounting standards for interim financial statements. These financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Consolidated Financial Statements for the years ended December 31, 2018, 2017, and 2016. In accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 855, “Subsequent Events,” the Company’s management has evaluated subsequent events for potential recognition or disclosure through the date of the issuance of these consolidated financial statements. The Company has one reportable segment. The Company’s chief operating decision maker evaluates the operations of the Company using consolidated information for purposes of allocating resources and assessing performance. Therefore, segments disclosures are not required. On October 17, 2018, the Company entered a definitive merger agreement with Oak Park River Forest Bankshares, Inc. (“Oak Park River Forest”), the parent company of Community Bank of Oak Park River Forest, to which the Company will acquire Oak Park River Forest through the merger of Oak Park River Forest with and into the Company, followed immediately by the merger of Community Bank of Oak Park River Forest with and into Byline Bank. On April 30, 2019, Byline completed its acquisition of Oak Park River Forest. Under the terms of the merger agreement, each share of Oak Park River Forest's common stock was converted into the right to receive 7.9321 shares of Byline common stock and $33.375 in cash. The value of the total merger consideration at closing was approximately $39.6 million. No other subsequent events were identified that would have required a change to the consolidated financial statements or disclosure in the notes to the consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity.

Accounting Pronouncements Recen

Accounting Pronouncements Recently Adopted or Issued	3 Months Ended
	Mar. 31, 2019
Accounting Changes And Error Corrections [Abstract]
Accounting Pronouncements Recently Adopted or Issued	Note 2—Accounting Pronouncements Recently Adopted or Issued The following reflect recent accounting pronouncements that have been adopted or are pending adoption by the Company. As the Company qualifies as an emerging growth company and has elected the extended transition period for complying with new or revised accounting pronouncements, it is not subject to new or revised accounting standards applicable to public companies during the extended transition period. The accounting pronouncements pending adoption below reflect effective dates for the Company as an emerging growth company with the extended transition period. Adopted Accounting Pronouncements Revenue from Contracts with Customers In May 2014, FASB issued Accounting Standards Update (“ASU”) No. 2014-09, deferred by ASU No. 2015-14 and clarifying standards, Revenue from Contracts with Customers , which creates Topics 606 and 610 and supersedes Topic 605, Revenue Recognition . The core principle of Topic 606 is that an entity recognizes 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 or services. In April 2016, FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing . The amendments in this ASU clarify the following two aspects of Topic 606: (1) identifying performance obligations and (2) licensing implementation guidance, while retaining the related principles for those areas. In May 2016, FASB issued ASU No. 2016-12, Narrow-Scope Improvements and Practical Expedients , amending ASC Topic 606, Revenue from Contracts with Customers . The amendments in this ASU affect only several narrow aspects of Topic 606. In November 2017, FASB issued ASU No. 2017-14, amending ASC Topic 606, Revenue from Contracts with Customers . The ASU amends the codification to incorporate additional previously issued guidance from the SEC. The SEC issued SAB 116 to bring existing SEC staff guidance into conformity with the FASB’s adoption of and amendments to ASC Topic 606. In general, the new guidance requires companies to use more judgment and make more estimates than under current guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The new authoritative guidance was initially effective for reporting periods after January 1, 2017 but was deferred to January 1, 2018. Given our emerging growth status, the Company adopted this new guidance on January 1, 2019 using the full retrospective method, meaning the standard is applied to all periods presented in the financial statements with the cumulative effect of initially applying the standard recognized at the beginning of the earliest period presented. The majority of the Company’s revenue streams, including interest and dividend income, servicing fees, and gains on sales of loans and investments, are outside the scope of Topic 606. Revenue streams reported as fees and service charges on deposits, ATM and interchange fees, and wealth management and trust income are within the scope of Topic 606. The Company applied the requirements of Topic 606 to the revenue streams that are within its scope. The adoption of Topic 606 did not result in any changes in the either timing or amount of recognized; there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition. However, the presentation of certain costs associated with our ATM and debit card income were offset against ATM and interchange income. This change in presentation resulted in $346,000 of expenses for the three months ended March 31, 2019 being netted against ATM and interchange fees and reported in non-interest income instead of as other non-interest expense in non-interest expense. In addition, to conform to the current period presentation, $305,000 of related expenses for the three months ended March 31, 2018 were reclassified from other non-interest expense in non-interest expense to being netted against ATM and interchange fees in non-interest income. The Company elected to apply the practical expedient and therefore does not disclose information about remaining performance obligations that have an original expected term of one year or less and allows the Company to expense costs related to obtaining a contract as incurred when the amortization period would have been one year or less. The Company adopted ASU 2014-09 using the full retrospective approach. The following table presents the impact of adopting the new revenue standard on our Consolidated Statements of Operations for the periods presented (in thousands): For the Three Months Ended For the Three Months Ended March 31, 2019 March 31, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 717 $ 1,063 $ (346 ) $ 913 $ 1,218 $ (305 ) Non-interest expense: Other non-interest expense $ 2,839 $ 3,185 $ (346 ) $ 1,752 $ 2,057 $ (305 ) Fees and service charges on deposits: Fees and service charges on deposits include transaction and non-transaction based deposit fees. Transaction based fees on deposit accounts are charged to deposit customers for specific services provided to the customer. These fees include such items as wire fees, official check fees, and overdraft fees. These are contracts specific to each individual transaction and do not extend beyond the individual transaction. The performance obligation is completed and the fees are recognized at the time the specific transactional service is provided to the customer. Non-transactional deposit fees are typically monthly account maintenance fees charged on deposit accounts. These are day-to-day contracts that can be canceled by either party without notice. The performance obligation is satisfied and the fees are recognized on a monthly basis after the service period is completed. ATM and interchange fees: ATM fees represent fees earned when a foreign debit or ATM card is used in a Byline Bank ATM. These fees are assessed and paid at the time of each transaction as the performance obligation is satisfied, which is at the point in time that the transaction is performed and approved. Interchange fees represent fees earned when a debit card issued by the Bank is used to purchase goods or services at a merchant. The merchant's bank pays the Bank a default interchange rate set by MasterCard on a transaction by transaction basis. Interchange fees are assessed as the performance obligation is satisfied, which is at the point in time the card transaction is authorized. The performance obligation is satisfied and the fees are earned when the cost of the transaction is charged to the Bank cardholders’ card. Direct expenses associated with ATM and debit cards are recorded as a net reduction against the ATM and interchange income. Wealth management and trust income Wealth management and trust income represents fees earned by the Bank for discretionary investment management, trust administration, fiduciary and/or custody services rendered. Fees vary and are based on a contract with the customer. Fee income is determined as a percentage of assets under management and is recognized over the period the underlying account is serviced. Although some trust appointments can last for generations, most contracts are generally cancellable at any time, with the customer subject to a pro-rated fee in the month of termination. Recognition and Measurement of Financial Assets and Financial Liabilities Recognition and Measurement of Financial Assets and Financial Liabilities In addition, the adoption of this ASU resulted in changing how the Company estimates the fair value of portfolio loans for disclosure purposes. Fair values are estimated first by stratifying the portfolios of loans with similar financial characteristics. Loans are segregated by type such as multifamily real estate, residential mortgage, nonresidential mortgage, commercial/agricultural, consumer and other. Each loan category is further segmented into fixed- and adjustable-rate interest terms. An estimate of fair value is then calculated based on discounted cash flows using as a discount rate based on the current rate offered on similar products, plus an adjustment for liquidity to reflect the non-homogeneous nature of the loans, as well as a quarterly loss rate based on historical losses to arrive at an estimated exit price fair value. Fair value for impaired loans is also based on recent appraisals or estimated cash flows discounted using rates commensurate with risk associated with the estimated cash flows. Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information. Derivatives and Hedging (Topic 815) In August 2017, FASB issued ASU No. 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this ASU better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company adopted the provisions of ASU No. 2017-12 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Upon adoption, the Company elected to reclassify $94.8 million of securities held-to-maturity to securities available-for-sale, which did not impact on the Consolidated Statements of Operations Compensation—Stock Compensation (Topic 718) In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting . The amendments in the ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all of the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification. (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified. (3) the classification of the modified award is an equity instrument or liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period, for reporting periods for which financial statements have not yet been issued. The amendments should be applied prospectively to an award modified on or after the adoption date. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-09 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Statement of Cash Flows (Topic 230) In August 2016, FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments . There is diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230 and other Topics. This ASU addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. Those eight issues are (1) debt prepayment or debt extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transactions, and (8) separately identifiable cash flows and application of the predominance principle. Current GAAP either is unclear or does not include specific guidance on these eight cash flow classification issues. These amendments provide guidance for each of the eight issues, thereby reducing current and potential future diversity in practice. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. Given the Company’s emerging growth company status, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company adopted the provisions of ASU No. 2016-15 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash Business Combinations (Topic 805) In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business . The guidance clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. This guidance is effective for annual and interim periods beginning after December 15, 2017. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-01 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Income Statement—Reporting Comprehensive Income (Topic 220) In February 2018, FASB issued ASU No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . The ASU helps organizations address certain stranded income tax effects in accumulated other comprehensive income (AOCI) resulting from the Tax Cuts and Jobs Act. The ASU provides reporting entities with an option to reclassify stranded tax effects within AOCI to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act (or portion thereof) is recorded. The ASU requires reporting entities to disclose: a description of the accounting policy for releasing income tax effects from AOCI; whether they elect to reclassify the stranded income tax effects from the Tax Cuts and Jobs Act; and information about the other income tax effects that are reclassified. The amendments affect any organization that is required to apply the provisions of Topic 220, Income Statement—Reporting Comprehensive Income , and has items of other comprehensive income for which the related tax effects are presented in other comprehensive income as required by GAAP. The amendments are effective for annual periods beginning after December 15, 2018, and interim periods within those fiscal years. The Company early adopted the new guidance on January 1, 2018. The adoption did not impact the Company’s Statements of Operations, and resulted in a reclassification of $763,000 from accumulated other comprehensive income (loss) to retained earnings. Fair Value Measurement (Topic 820) In August 2018, FASB issued ASU No. 2018-13, Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement . The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820. The amendments remove the disclosure requirements for the amount and reasons for transfers between Level 1 and Level 2 securities of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation processes for Level 3 fair value measurement. The amendments modify the disclosure requirements as follows: in lieu of a rollforward for Level 3 fair value measurements, a nonpublic entity is required to disclose transfers into and out of Level 3 of the fair value hierarchy and purchases and issues of Level 3 assets and liabilities; for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The amendments add the following disclosure requirements: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Early adoption is permitted. The Company early adopted these amendments in 2018, which did not have a material impact on the Company’s Consolidated Financial Statements. Issued Accounting Pronouncements Pending Adoption Leases (Topic 842) In February 2016, FASB issued ASU No. 2016-02, Leases . The amendments in this ASU require lessees to recognize the following for all leases (with the exception of short-term) at the commencement date; a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The amendments in this ASU leave lessor accounting largely unchanged, although certain targeted improvements were made to align lessor accounting with the lessee accounting model. This ASU simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees will no longer be provided with a source of off-balance sheet financing. The amendments in this ASU are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early application is permitted upon issuance. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. Lessees and lessors may not apply a full retrospective transition approach. The Company is evaluating the new guidance and its impact on the Company’s Consolidated Statements of Operations and Consolidated Statements of Financial Condition. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2020. The Company expects an increase in assets and liabilities as a result of recognizing additional right-to-use assets and liabilities under lease contracts in which the Company is lessee. While the Company has not quantified the impact of this ASU on its leasing portfolio, it does not expect a change in its accounting for the initial direct costs of leases. Financial Instruments—Credit Losses (Topic 326) In June 2016, FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments . Current GAAP requires an “incurred loss” methodology for recognizing credit losses that delays recognition until it is probable a loss has been incurred. The main objective of this ASU is to provide financial statement users with more decision-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. The amendments in this ASU replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendments in this ASU require a financial asset (or group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. The measurement of expected credit losses will be based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendments in this ASU broaden the information that an entity must consider in developing its expected credit loss estimate for assets measured either collectively or individually. The use of forecasted information incorporates more timely information in the estimate of expected credit loss, which will be more decision useful to users of the financial statements. The amendments in this ASU will be effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2021. The Company is still evaluating the effects this ASU will have on the Company’s Consolidated Financial Statements. While the Company has not quantified the impact of this ASU, it does expect changing from the current incurred loss model to an expected loss model will result in an earlier recognition of losses. Nonrefundable Fees and Other Costs (Subtopic 310-20) In March 2017, FASB issued ASU No. 2017-08, Receivables—Nonrefundable Fees and Other Costs. The amendments in the ASU shorten the amortization period for certain callable debt securities held at a premium at the earliest call date. Under current GAAP, the Company amortizes the premium as an adjustment of yield over the contractual life of the instrument. As a result, upon exercise of a call on a callable debt security held at a premium, the unamortized premium is charged to earnings. The ASU shortens the amortization period for certain callable debt securities held at a premium and requires the premium to be amortized to the earliest call date. However, the amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amendments are effective for annual periods beginning after December 15, 2019, and interim periods within annual periods beginning after December 15, 2020. Early adoption is permitted. The Company is required to apply the amendments on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2020. The Company is currently evaluating the provisions of ASU No. 2017-08 to determine the potential impact the new standard will have on the Company’s Consolidated Financial Statements.

Acquisition of a Business

Acquisition of a Business	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Acquisition of a Business	Note 3—Acquisition On May 31, 2018, the Company acquired all common stock of First Evanston Bancorp, Inc. (“First Evanston”) and its subsidiaries pursuant to an Agreement and Plan of Merger, dated as of November 27, 2017 (the “Merger Agreement”). First Evanston operated two wholly owned subsidiaries, First Bank & Trust and First Evanston Bancorp Trust I. First Evanston was merged with and into Byline. As a result of the merger, First Evanston’s subsidiary bank, First Bank & Trust, was merged with and into Byline Bank, with Byline Bank as the surviving bank. The acquisition improves the Company’s footprint in the Chicagoland market, diversifies its commercial banking business, and strengthens the core deposit base. At the effective time of the merger (the “Effective Time”), each share of First Evanston’s common stock was converted into the right to receive: (1) 3.994 shares of Byline’s common stock, and (2) an amount in cash equal to $27.0 million divided by the number of outstanding shares of First Evanston common stock as of the closing date, with cash paid in lieu of any fractional shares. The per share cash consideration was based on the total $27.0 million divided by the outstanding shares of First Evanston common stock, or $16.136 per outstanding share. Based on the closing price of shares of the Company’s common stock of $21.62, as reported by the New York Stock Exchange, and 6,682,850 shares of common stock issued with respect to the outstanding shares of First Evanston common stock, the stock consideration was valued at $144.5 million. Options to acquire 144,090 shares of First Evanston common stock that were outstanding at the Effective Time were converted into options to acquire 680,787 shares of Byline common stock, resulting in a consideration value of $7.6 million. The value of the total merger consideration at closing was $179.1 million before the issuance costs of $852,000. The transaction resulted in goodwill of $73.6 million, which is nondeductible for tax purposes, as this acquisition was a nontaxable transaction. Goodwill represents the premium paid over the fair value of the net tangible and intangible assets acquired and reflects related synergies expected from the combined operations. The Company incurred First Evanston merger-related expenses, including acquisition advisory expenses, The acquisition of First Evanston was accounted for using the acquisition method of accounting in accordance with ASC Topic 805. Assets acquired, liabilities assumed and consideration exchanged were recorded at their respective acquisition date fair values. Determining the fair value of assets and liabilities involves significant judgment regarding methods and assumptions used to calculate estimated fair values. The fair value adjustments associated with this transaction were finalized during the fourth quarter of 2018. The following table presents a summary of the fair values of assets acquired and liabilities assumed as of the acquisition date: Assets Cash and cash equivalents $ 47,378 Securities available-for-sale 128,063 Restricted stock 1,360 Loans 916,011 Premises and equipment 15,890 Other intangible assets 22,276 Deferred tax assets, net 2,302 Other assets 8,845 Total assets acquired 1,142,125 Liabilities Deposits 1,022,268 Junior subordinated debentures 8,497 Accrued expenses and other liabilities 5,844 Total liabilities assumed 1,036,609 Net assets acquired $ 105,516 Consideration paid Common stock (6,682,850 shares issued at $21.62 per share) 144,483 Outstanding stock options converted to Byline stock options 7,644 Cash paid 27,004 Total consideration paid 179,131 Goodwill $ 73,615 The following table presents the acquired non-impaired loans as of the acquisition date: Fair value $ 890,986 Gross contractual amounts receivable 1,057,374 Estimate of contractual cash flows not expected to be collected (1) 36,544 Estimate of contractual cash flows expected to be collected 1,020,830 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default. The discount on the acquired non-impaired loans is being accreted into income over the life of the loans on an effective yield basis. The following table provides the unaudited pro forma information for the results of operations for the three months ended March 31, 2018, as if the acquisition had occurred on January 1, 2018. The pro forma results combine the historical results of First Evanston into the Company’s Consolidated Statements of Operations, including the impact of certain acquisition accounting adjustments, which includes loan discount accretion, intangible assets amortization, deposit premium accretion, and borrowing, net of discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2018. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The acquisition-related expenses that have been recognized are included in net income in the following table for the three months ended March 31, 2018. March 31, 2018 Total revenues (net interest income and non-interest income) $ 57,697 Net income $ 10,458 Earnings per share—basic $ 0.29 Earnings per share—diluted $ 0.28 The operating results of the Company include the operating results produced by the acquired assets and assumed liabilities of First Evanston for the period beginning June 1, 2018 through March 31, 2019. Revenues and earnings of the acquired company since the acquisition date have not been disclosed as it is not practicable as First Evanston was merged into the Company and separate financial information is not readily available. On April 30, 2019, the Company acquired all common stock of Oak Park River Forest Bankshares, Inc. and its subsidiary pursuant to an Agreement and Plan of Merger, dated as of October 17, 2018 (the “OPRF Merger Agreement”). Oak Park River Forest operated one wholly owned subsidiary, Community Bank of Oak Park and River Forest. Oak Park River Forest was merged with and into Byline. As a result of the merger, Oak Park River Forest’s subsidiary bank, Community Bank of Oak Park and River Forest, was merged with and into Byline Bank, with Byline Bank as the surviving bank. The acquisition improves the Company’s footprint in the Chicagoland market, diversifies its commercial banking business, and strengthens the core deposit base. At the effective time of the merger (the “OPRF Effective Time”), each share of Oak Park River Forest’s common stock was converted into the right to receive: (1) 7.9321 shares of Byline’s common stock, and (2) an amount in cash equal to $6.1 million divided by the number of outstanding shares of Oak Park River Forest common stock as of the closing date, with cash paid in lieu of any fractional shares. The per share cash consideration was based on the total $6.1 million divided by the outstanding shares of Oak Park River Forest common stock, or $33.375 per outstanding share. Based on the closing price of shares of the Company’s common stock of $20.02, as reported by the New York Stock Exchange, and 1,464,558 shares of common stock issued with respect to the outstanding shares of Oak Park River Forest common stock, the stock consideration was valued at $29.3 million. Options to acquire 35,870 shares of Oak Park River Forest common stock that were outstanding at the OPRF Effective Time were cancelled, at the option holders election, in exchange for a cash payment in accordance with the OPRF Merger agreement, resulting in a consideration value of $4.2 million. As of March 31, 2019, prior to the impact of acquisition fair value adjustments, Oak Park River Forest had $323.5 million in assets, including $30.8 million of securities, $269.5 million of loans, and $285.7 million of total deposits.

Securities

Securities	3 Months Ended
	Mar. 31, 2019
Investments Debt And Equity Securities [Abstract]
Securities	Note 4—Securities The following March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Equity and other securities, at fair value Mutual funds $ 2,882 $ 2,882 Equity securities 4,334 4,334 Total $ 7,216 $ 7,216 March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 57,323 $ 162 $ (98 ) $ 57,387 U.S. Government agencies 187,458 816 (772 ) 187,502 Obligations of states, municipalities, and political subdivisions 82,049 749 (231 ) 82,567 Residential mortgage-backed securities Agency 347,166 753 (7,435 ) 340,484 Non-agency 132,071 814 (1,219 ) 131,666 Commercial mortgage-backed securities Agency 100,400 78 (2,665 ) 97,813 Non-agency 31,380 — (545 ) 30,835 Corporate securities 36,666 59 (426 ) 36,299 Other securities — — — — Total $ 974,513 $ 3,431 $ (13,391 ) $ 964,553 March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 4,425 $ 22 $ (16 ) $ 4,431 Total $ 4,425 $ 22 $ (16 ) $ 4,431 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 52,775 $ 81 $ (189 ) $ 52,667 U.S. Government agencies 187,427 367 (1,296 ) 186,498 Obligations of states, municipalities, and political subdivisions 60,686 133 (586 ) 60,233 Residential mortgage-backed securities Agency 284,038 101 (11,176 ) 272,963 Non-agency 84,998 199 (1,576 ) 83,621 Commercial mortgage-backed securities Agency 93,543 55 (3,164 ) 90,434 Non-agency 31,458 — (1,000 ) 30,458 Corporate securities 34,716 67 (610 ) 34,173 Other securities 4,613 2,127 (131 ) 6,609 Total $ 834,254 $ 3,130 $ (19,728 ) $ 817,656 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,835 $ 40 $ (210 ) $ 23,665 Residential mortgage-backed securities Agency 40,082 93 (531 ) 39,644 Non-agency 35,349 — (919 ) 34,430 Total $ 99,266 $ 133 $ (1,660 ) $ 97,739 The Company did not classify securities as trading during the three months ended March 31, 2019 or during 2018. The Company adopted the provisions of ASU No. 2016-01 as of January 1, 2019. The adoption of this ASU resulted in the reclassification of available-for-sale equity securities, at fair value to a separate line item on the Company’s Consolidated Statements of Financial Condition, and the reclassification of $1.4 million from other comprehensive income to retained earnings, representing the net unrealized gain, net of tax, on available-for-sale for sale equity securities at the date of adoption. At December 31, 2018, the Company held $6.6 million of available-for-sale equity investment securities which were reported as available-for-sale securities, at fair value, and are now reported as equity and other securities, at fair value. Additionally, the Company adopted the provisions of ASU No. 2017-12 on January 1, 2019, and elected to reclassify $94.8 million of securities held-to-maturity to securities available-for-sale, which did not impact on the Consolidated Statements of Operations. Gross unrealized losses and fair values, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2019 and December 31, 2018, are summarized as follows: Less than 12 Months 12 Months or Longer Total March 31, 2019 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 13 $ 7,965 $ (2 ) $ 14,891 $ (96 ) $ 22,856 $ (98 ) U.S. Government agencies 20 38,421 (50 ) 50,613 (722 ) 89,034 (772 ) Obligations of states, municipalities and political subdivisions 30 542 (1 ) 20,376 (230 ) 20,918 (231 ) Residential mortgage-backed securities Agency 57 — — 276,827 (7,435 ) 276,827 (7,435 ) Non-agency 13 — — 82,304 (1,219 ) 82,304 (1,219 ) Commercial mortgage-backed securities Agency 11 25,364 (128 ) 65,029 (2,537 ) 90,393 (2,665 ) Non-agency 5 — — 30,835 (545 ) 30,835 (545 ) Corporate securities 12 15,756 (229 ) 8,250 (197 ) 24,006 (426 ) Other securities — — — — — — — Total 161 $ 88,048 $ (410 ) $ 549,125 $ (12,981 ) $ 637,173 $ (13,391 ) Less than 12 Months 12 Months or Longer Total March 31, 2019 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 4 $ — $ — $ 2,605 $ (16 ) $ 2,605 $ (16 ) Total 4 $ — $ — $ 2,605 $ (16 ) $ 2,605 $ (16 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 18 $ 23,835 $ (52 ) $ 9,865 $ (137 ) $ 33,700 $ (189 ) U.S. Government agencies 25 43,487 (80 ) 50,101 (1,216 ) 93,588 (1,296 ) Obligations of states, municipalities and political subdivisions 56 13,926 (97 ) 18,563 (489 ) 32,489 (586 ) Residential mortgage-backed securities Agency 42 4,288 (45 ) 254,121 (11,131 ) 258,409 (11,176 ) Non-agency 8 59,107 (1,378 ) 4,009 (198 ) 63,116 (1,576 ) Commercial mortgage-backed securities Agency 9 21,356 (447 ) 52,640 (2,717 ) 73,996 (3,164 ) Non-agency 5 — — 30,458 (1,000 ) 30,458 (1,000 ) Corporate securities 15 25,762 (342 ) 4,642 (268 ) 30,404 (610 ) Other securities 1 — — 2,844 (131 ) 2,844 (131 ) Total 179 $ 191,761 $ (2,441 ) $ 427,243 $ (17,287 ) $ 619,004 $ (19,728 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 23 $ 8,127 $ (58 ) $ 8,792 $ (152 ) $ 16,919 $ (210 ) Residential mortgage-backed securities Agency 16 6,625 (150 ) 21,139 (381 ) 27,764 (531 ) Non-agency 7 21,499 (503 ) 12,931 (416 ) 34,430 (919 ) Total 46 $ 36,251 $ (711 ) $ 42,862 $ (949 ) $ 79,113 $ (1,660 ) Certain T o available-for-sale There were no sales of securities were three months ended March 31, 2019 income Securities pledged at March 31, 2019 and December 31, 2018 had carrying amounts of $223.9 million and $244.7 million, At March 31, 2019, the Amortized Cost Fair Value Available-for-sale Due in one year or less $ 83,952 $ 83,767 Due from one to five years 161,739 161,679 Due from five to ten years 91,146 91,405 Due after ten years 26,659 26,904 Mortgage-backed securities 611,017 600,798 Total $ 974,513 $ 964,553 Held-to-maturity Due from one to five years $ 3,262 $ 3,264 Due from five to ten years 1,163 1,167 Total $ 4,425 $ 4,431 Equity and other securities, at fair value Due after ten years $ 695 $ 695 No defined maturity 6,521 6,521 Total $ 7,216 $ 7,216

Loan and Lease Receivables

Loan and Lease Receivables	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Loan and Lease Receivables	Note 5—Loan Outstanding loan and lease receivables as of the dates shown were categorized as follows: March 31, December 31, 2019 2018 Commercial real estate $ 1,262,236 $ 1,261,594 Residential real estate 699,088 704,899 Construction, land development, and other land 214,562 186,258 Commercial and industrial 1,189,710 1,145,240 Installment and other 12,766 13,675 Lease financing receivables 186,743 187,797 Total loans and leases 3,565,105 3,499,463 Net unamortized deferred fees and costs (764 ) (1,293 ) Initial direct costs 3,225 3,456 Allowance for loan and lease losses (27,106 ) (25,201 ) Net loans and leases $ 3,540,460 $ 3,476,425 March 31, December 31, 2019 2018 Lease financing receivables Net minimum lease payments $ 203,238 $ 204,646 Unguaranteed residual values 1,511 1,535 Unearned income (18,006 ) (18,384 ) Total lease financing receivables 186,743 187,797 Initial direct costs 3,225 3,456 Lease financial receivables before allowance for lease losses $ 189,968 $ 191,253 Total loans and leases consist of originated loans and leases, acquired impaired loans and acquired non-impaired loans and leases. At March 31, 2019 and December 31, 2018, total loans and leases included the guaranteed amount of U.S. government guaranteed loans of $129.0 million and $108.7 million, respectively. At March 31, 2019 and December 31, 2018, installment and other loans included overdraft deposits of $1.1 million and $1.7 million, respectively, which were reclassified as loans. At March 31, 2019 and December 31, 2018, loans and loans held for sale pledged as security for borrowings were $1.4 billion. The minimum Minimum Lease Payments 2019 $ 56,181 2020 62,573 2021 43,337 2022 27,072 2023 12,269 Thereafter 1,806 Total $ 203,238 Originated Topic do not qualify to be accounted for as acquired impaired loans and Topic March 31, 2019 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 738,832 $ 141,199 $ 382,252 $ 1,262,283 Residential real estate 494,877 106,764 97,395 699,036 Construction, land development, and other land 181,427 3,111 29,121 213,659 Commercial and industrial 900,709 11,963 277,146 1,189,818 Installment and other 11,082 374 1,346 12,802 Lease financing receivables 160,607 — 29,361 189,968 Total loans and leases $ 2,487,534 $ 263,411 $ 816,621 $ 3,567,566 December 31, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 652,234 $ 146,808 $ 462,565 $ 1,261,607 Residential real estate 466,309 113,934 124,659 704,902 Construction, land development, and other land 144,128 3,779 37,442 185,349 Commercial and industrial 803,508 12,617 328,672 1,144,797 Installment and other 11,718 404 1,596 13,718 Lease financing receivables 159,901 — 31,352 191,253 Total loans and leases $ 2,237,798 $ 277,542 $ 986,286 $ 3,501,626 Acquired impaired loans —As part of the First Evanston acquisition, the Bank acquired impaired loans that are accounted for under ASC 310-30 in the amount of $25.0 million. Refer to Note 3—Acquisition of a Business for additional information regarding the transaction. There were no other acquired impaired loans purchased during 2019 or 2018 Undiscounted contractual cash flows $ 33,594 Undiscounted cash flows not expected to be collected (non-accretable difference) (5,003 ) Undiscounted cash flows expected to be collected 28,591 Accretable yield at acquisition (3,566 ) Estimated fair value of impaired loans acquired at acquisition $ 25,025 The outstanding March 31, 2019 December 31, 2018 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 194,328 $ 141,199 $ 216,137 $ 146,808 Residential real estate 155,075 106,764 173,962 113,934 Construction, land development, and other land 10,849 3,111 11,962 3,779 Commercial and industrial 16,794 11,963 24,972 12,617 Installment and other 1,205 374 1,735 404 Total acquired impaired loans $ 378,251 $ 263,411 $ 428,768 $ 277,542 The following table summarizes the changes in accretable yield for acquired impaired loans for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Beginning balance $ 37,115 $ 36,446 Additions — — Accretion to interest income (5,250 ) (5,691 ) Reclassification from (to) nonaccretable difference, net (2,525 ) 8,545 Ending balance $ 29,340 $ 39,300 Acquired non-impaired loans and leases —The Company acquired non-impaired loans as part of the First Evanston acquisition in the amount of $891.0 million. Refer to Note 3—Acquisition of a Business for additional information regarding the transaction. The unpaid March 31, 2019 December 31, 2018 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 391,806 $ 382,252 $ 473,262 $ 462,565 Residential real estate 99,828 97,395 127,478 124,659 Construction, land development, and other land 30,081 29,121 38,494 37,442 Commercial and industrial 284,997 277,146 344,879 328,672 Installment and other 1,375 1,346 1,831 1,596 Lease financing receivables 30,852 29,361 32,977 31,352 Total acquired non-impaired loans and leases $ 838,939 $ 816,621 $ 1,018,921 $ 986,286

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	Note 6—Allowance for Loans and leases The following March 31, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Allowance for loan and lease losses Three months ended Beginning balance $ 7,540 $ 1,751 $ 466 $ 12,932 $ 49 $ 2,463 $ 25,201 Provisions 442 218 70 3,032 14 223 3,999 Charge-offs (1,351 ) — — (352 ) — (645 ) (2,348 ) Recoveries 29 1 — 18 — 206 254 Ending balance $ 6,660 $ 1,970 $ 536 $ 15,630 $ 63 $ 2,247 $ 27,106 Ending balance: Individually evaluated for impairment $ 1,403 $ 34 $ — $ 6,122 $ — $ — $ 7,559 Collectively evaluated for impairment 4,141 1,516 536 8,200 61 2,247 16,701 Loans acquired with deteriorated credit quality 1,116 420 — 1,308 2 — 2,846 Total allowance for loan and lease losses $ 6,660 $ 1,970 $ 536 $ 15,630 $ 63 $ 2,247 $ 27,106 March 31, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Loans and leases ending balance: Individually evaluated for impairment $ 17,354 $ 2,060 $ — $ 24,384 $ — $ — $ 43,798 Collectively evaluated for impairment 1,103,730 590,212 210,548 1,153,471 12,428 189,968 3,260,357 Loans acquired with deteriorated credit quality 141,199 106,764 3,111 11,963 374 — 263,411 Total loans and leases $ 1,262,283 $ 699,036 $ 213,659 $ 1,189,818 $ 12,802 $ 189,968 $ 3,567,566 March 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Allowance for loan and lease losses Three months ended Beginning balance $ 4,794 $ 1,638 $ 222 $ 7,418 $ 41 $ 2,593 $ 16,706 Provisions (releases) 934 (74 ) 397 3,424 20 414 5,115 Charge-offs (409 ) — (418 ) (3,085 ) — (510 ) (4,422 ) Recoveries — — — 6 — 235 241 Ending balance $ 5,319 $ 1,564 $ 201 $ 7,763 $ 61 $ 2,732 $ 17,640 Ending balance: Individually evaluated for impairment $ 1,572 $ 153 $ — $ 2,963 $ 14 $ — $ 4,702 Collectively evaluated for impairment 1,827 1,036 177 3,626 11 2,732 9,409 Loans acquired with deteriorated credit quality 1,920 375 24 1,174 36 — 3,529 Total allowance for loan and lease losses $ 5,319 $ 1,564 $ 201 $ 7,763 $ 61 $ 2,732 $ 17,640 March 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Loans and leases ending balance: Individually evaluated for impairment $ 12,375 $ 2,029 $ — $ 12,598 $ 14 $ — $ 27,016 Collectively evaluated for impairment 670,538 426,272 111,914 548,076 3,667 181,461 1,941,928 Loans acquired with deteriorated credit quality 157,956 139,858 5,156 8,055 449 — 311,474 Total loans and leases $ 840,869 $ 568,159 $ 117,070 $ 568,729 $ 4,130 $ 181,461 $ 2,280,418 The Company increased the allowance for loan and lease losses by $1.9 million and $934,000 for the three months ended March 31, 2019 and 2018, respectively. For acquired impaired loans, the Company increased the allowance for loan and lease losses by $111,000 for the three months ended March 31, 2019 and decreased the allowance for loans and lease losses by $345,000 for the three months ended March 31, 2018. For loans individually evaluated for impairment, the Company increased the allowance for loan and lease losses by $910,000 and $737,000 for the three months ended March 31, 2019 and 2018, respectively. For loans collectively evaluated for impairment, the Company increased the allowance for loan and lease losses by $884,000 and $542,000 for the three months ended March 31, 2019 and 2018, respectively. The following and March 31, 2019 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 11,643 $ 13,669 $ — Residential real estate 1,838 1,841 — Commercial and industrial 10,907 12,785 — With an allowance recorded Commercial real estate 5,711 5,959 1,403 Residential real estate 222 222 34 Commercial and industrial 13,477 14,111 6,122 Total impaired loans $ 43,798 $ 48,587 $ 7,559 December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 6,110 $ 7,693 $ — Residential real estate 1,886 1,858 — Commercial and industrial 11,193 13,961 — With an allowance recorded Commercial real estate 5,873 6,313 2,191 Residential real estate 251 253 61 Commercial and industrial 10,601 11,153 4,397 Total impaired loans $ 35,914 $ 41,231 $ 6,649 The following tables summarize the average recorded investment and interest income recognized for loans and leases considered impaired, which excludes acquired impaired loans, for the three months ended as follows: March 31, 2019 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 7,345 $ 119 Residential real estate 1,541 13 Commercial and industrial 11,381 126 With an allowance recorded Commercial real estate 5,186 48 Residential real estate 226 2 Commercial and industrial 11,377 154 Total impaired loans $ 37,056 $ 462 March 31, 2018 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 9,039 $ 103 Residential real estate 1,930 10 Commercial and industrial 7,300 62 With an allowance recorded Commercial real estate 4,122 37 Residential real estate 351 1 Commercial and industrial 6,975 102 Installment and other 14 — Total impaired loans $ 29,731 $ 315 For purposes The following March 31, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 996,417 $ 554,892 $ 172,720 $ 989,123 $ 12,404 $ 186,230 $ 2,911,786 Watch 87,343 29,753 37,828 129,730 17 42 284,713 Special Mention 19,904 5,410 — 33,489 — 2,512 61,315 Substandard 17,420 2,217 — 25,513 7 328 45,485 Doubtful — — — — — 856 856 Loss — — — — — — — Total $ 1,121,084 $ 592,272 $ 210,548 $ 1,177,855 $ 12,428 $ 189,968 $ 3,304,155 December 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 1,009,041 $ 553,665 $ 147,123 $ 962,291 $ 9,997 $ 188,314 $ 2,870,431 Watch 76,276 29,522 31,376 112,996 3,302 80 253,552 Special Mention 17,602 5,656 3,071 34,314 — 1,794 62,437 Substandard 11,880 2,125 — 22,579 15 818 37,417 Doubtful — — — — — 247 247 Loss — — — — — — — Total $ 1,114,799 $ 590,968 $ 181,570 $ 1,132,180 $ 13,314 $ 191,253 $ 3,224,084 The following tables summarize contractual delinquency information for acquired non-impaired and originated loans and leases by category at March 31, 2019 and December 31, 2018: March 31, 2019 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 17,155 $ 1,944 $ — $ 9,677 $ 28,776 $ 1,092,308 $ 1,121,084 Residential real estate 1,337 1,248 — 2,070 4,655 587,617 592,272 Construction, land development, and other land 12,009 — — — 12,009 198,539 210,548 Commercial and industrial 11,454 117 — 15,931 27,502 1,150,353 1,177,855 Installment and other 12 6 — 5 23 12,405 12,428 Lease financing receivables 1,093 328 — 856 2,277 187,691 189,968 Total $ 43,060 $ 3,643 $ — $ 28,539 $ 75,242 $ 3,228,913 $ 3,304,155 December 31, 2018 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 6,659 $ 2,145 $ — $ 9,484 $ 18,288 $ 1,096,511 $ 1,114,799 Residential real estate 4,488 711 — 1,815 7,014 583,954 590,968 Construction, land development, and other land — — — — — 181,570 181,570 Commercial and industrial 5,829 1,376 — 13,932 21,137 1,111,043 1,132,180 Installment and other 1,932 4 — 12 1,948 11,366 13,314 Lease financing receivables 789 530 — 591 1,910 189,343 191,253 Total $ 19,697 $ 4,766 $ — $ 25,834 $ 50,297 $ 3,173,787 $ 3,224,084 Trouble debt restructurings are granted due to borrower financial difficulty and provide for a modification of loan repayment terms. TDRs are treated in the same manner as impaired loans for purposes of calculating the allowance for loan and lease losses. The tables below present TDRs by loan category as of March 31, 2019 and December 31, 2018: March 31, 2019 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 4 $ 1,486 $ 1,486 $ — $ 124 Commercial and industrial 2 216 216 — 99 Residential real estate 2 219 219 — — Total accruing 8 1,921 1,921 — 223 Non-accruing: Commercial real estate 9 2,690 2,119 571 141 Commercial and industrial 8 6,871 5,000 1,871 1,271 Total non-accruing 17 9,561 7,119 2,442 1,412 Total troubled debt restructurings 25 $ 11,482 $ 9,040 $ 2,442 $ 1,635 December 31, 2018 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 4 $ 1,508 $ 1,508 $ — $ 113 Commercial and industrial 2 191 191 — 100 Residential real estate 1 114 114 — — Total accruing 7 1,813 1,813 — 213 Non-accruing: Commercial real estate 9 2,512 2,471 41 743 Commercial and industrial 6 6,714 4,843 1,871 1,290 Total non-accruing 15 9,226 7,314 1,912 2,033 Total troubled debt restructurings 22 $ 11,039 $ 9,127 $ 1,912 $ 2,246 In addition, Loans modified three months ended March 31, 2019 For the Three Months Ended March 31, 2019 2018 Accruing: Beginning balance $ 1,813 $ 1,061 Additions 113 — Net payments (5 ) (24 ) Net transfers from non-accrual — — Ending balance 1,921 1,037 Non-accruing: Beginning balance 7,314 1,569 Additions 246 — Net payments 89 (332 ) Charge-offs (530 ) (144 ) Net transfers from accrual — — Ending balance 7,119 1,093 Total troubled debt restructurings 9,040 2,130 There were no troubled debt restructurings that subsequently defaulted within At March 31, 2019 and December 31, 2018, the During the , the

Servicing Assets

Servicing Assets	3 Months Ended
	Mar. 31, 2019
Transfers And Servicing [Abstract]
Servicing Assets	Note 7—Servicing Activity for the three months ended March 31, 2019 and 2018 is Three Months Ended March 31, 2019 2018 Beginning balance $ 19,693 $ 21,400 Additions, net 1,102 2,102 Changes in fair value (1,261 ) (1,887 ) Ending balance $ 19,534 $ 21,615 Loans serviced as of and were as follows: March 31, December 31, 2019 2018 Loan portfolios serviced for: SBA guaranteed loans $ 1,160,938 $ 1,151,915 USDA guaranteed loans 103,503 106,184 Total $ 1,264,441 $ 1,258,099 Loan servicing revenue totaled $2.5 million for the three months ended March 31, 2019 and 2018. Loan servicing asset revaluation, which represents the changes in fair value of servicing assets, resulted in downward valuations of $1.3 and $1.9 million for the three months ended March 31, 2019 and 2018, respectively. The fair Generally, as interest rates rise on variable rate loans, loan prepayments increase due to an increase in refinance activity, which may result in a decrease in the fair value of servicing assets. Measurement of fair value is limited to the conditions existing and the assumptions used as of a particular point in time, and those assumptions may change over time. Refer to Note 16—Fair Value Measurement for further details.

Other Real Estate Owned

Other Real Estate Owned	3 Months Ended
	Mar. 31, 2019
Banking And Thrift [Abstract]
Other Real Estate Owned	Note 8—Other Real Estate Owned The following table presents the change in other real estate owned (“OREO”) for the three months ended March 31, 2019 and 2018 Three Months Ended March 31, 2019 2018 Beginning balance $ 5,314 $ 10,626 Net additions to OREO 230 1,044 Proceeds from sales of OREO (628 ) (1,263 ) Gains (losses) on sales of OREO (33 ) 140 Valuation adjustments (84 ) (81 ) Ending balance $ 4,799 $ 10,466 At March 31, 2019 and December 31, 2018, the balance of real estate owned included $700,000 and $838,000, respectively, of foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property. At March 31, 2019 and December 31, 2018, the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings were in process is $2.7 million and $2.3 million, respectively. Proceeds from sales of OREO include proceeds from internally financed sales of OREO of $183,000 for the three months ended March 31, 2019. There were no internally financed sales of OREO for the three months ended March 3, 2018.

Goodwill, Core Deposit Intangib

Goodwill, Core Deposit Intangible and Other Intangible Assets	3 Months Ended
	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill, Core Deposit Intangible and Other Intangible Assets	Note 9—Goodwill, Core Deposit Intangible and Other Intangible Assets The following tables summarize the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the three months ended March 31, 2019 and 2018 Three Months Ended March 31, 2019 2018 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 128,177 $ 30,360 $ 3,059 $ 54,562 $ 16,720 $ — Amortization — (1,706 ) (67 ) — (761 ) — Ending balance $ 128,177 $ 28,654 $ 2,992 $ 54,562 $ 15,959 $ — Accumulated amortization N/A $ 20,592 $ 224 N/A $ 14,227 N/A Weighted average remaining amortization period N/A 6.6 Years 11.2 Years N/A 5.4 Years N/A The Company added additional goodwill, core deposit intangible assets, and customer relationship intangible assets in conjunction with the First Evanston acquisition. Please refer to Note 3—Acquisition of a Business for further details. The following table presents the estimated amortization expense for core deposit intangible, customer relationship intangible, and other intangible assets recognized at March 31, 2019: Estimated Amortization 2019 $ 5,153 2020 6,476 2021 6,025 2022 5,578 2023 3,645 Thereafter 4,769 Total $ 31,646

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 10—Income The Company uses an estimated annual effective tax rate method in computing its interim tax provision. This effective tax rate is based on forecasted annual pre-tax income, permanent tax differences and statutory tax rates. The effective tax rate for the three months ended March 31, 2019 and 2018 was 27.6% and 16.3%, respectively. The current effective tax rate reflects the passage of the Tax Cuts and Jobs Act (the “Tax Act”), which was enacted on December 22, 2017. Among other things, the Tax Act reduces the corporate federal income tax rate from 35% to 21%, effective January 1, 2018. Also on December 22, 2017, the SEC issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for the Tax Act’s impact. SAB 118 provides a measurement period, not to extend beyond one year from the date of enactment during which a company, acting in good faith, may complete the accounting for the impacts of the Tax Act. The Company recorded an additional discrete income tax benefit of $724,000 during the first quarter of 2018. This adjustment includes the impact of the federal income tax rate decrease due to the Tax Act (enacted on December 22, 2017) on our net deferred tax assets. The re-measurement of our net deferred tax assets due to the Tax Act was determined to be provisional at March 31, 2018. Net deferred tax assets decreased to $30.5 million at compared to $35.6 million at . The net decrease in the total net deferred tax assets recorded as of was a result of a decrease in unrealized losses on available-for-sale securities and utilization of operating loss carryforwards during the period

Deposits

Deposits	3 Months Ended
	Mar. 31, 2019
Deposits [Abstract]
Deposits	Note 11—Deposits The composition of deposits was as follows as of March 31, 2019 and December 31, 2018: March 31, December 31, 2019 2018 Non-interest-bearing demand deposits $ 1,163,255 $ 1,192,873 Interest-bearing checking accounts 305,393 296,339 Money market demand accounts 611,634 640,401 Other savings 468,524 476,418 Time deposits (below $250,000) 967,999 911,603 Time deposits ($250,000 and above) 291,711 232,282 Total deposits $ 3,808,516 $ 3,749,916 Time deposits of $250,000 or more included $70.0 and $50.0 million of brokered deposits at March 31, 2019 and December 31, 2018, respectively.

Federal Home Loan Bank Advances

Federal Home Loan Bank Advances	3 Months Ended
	Mar. 31, 2019
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank Advances	Note 12—Federal The following March 31, December 31, 2019 2018 Federal Home Loan Bank advances $ 425,000 $ 425,000 Weighted average cost 2.59 % 2.56 % At March 31, 2019, fixed-rate advances totaled $370.0 million with interest rates ranging from 2.56% to 2.61% , and May The Company’s required investment in FHLB stock is $4.50 for every $100 in advances. At and , the Bank has additional borrowing capacity from the FHLB of $1.3 billion, subject to the availability of proper collateral. The Company hedges interest rates on borrowed funds using interest rate swaps through which the Company receives variable amounts and pays fixed amounts. Refer to Note 17—Derivative Instruments and Hedging Activities for additional information.

Other Borrowings

Other Borrowings	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Other Borrowings	Note 13—Other Borrowings The following is a summary of the Company’s other borrowings as of March 31, 2019 and December 31, 2018: March 31, December 31, 2019 2018 Securities sold under agreements to repurchase $ 34,369 $ 34,166 Line of credit — — Total $ 34,369 $ 34,166 Securities On On April 30, 2019, the Company drew on the line of credit for $5.7 million and selected the LIBOR plus 225 basis points interest rate option. The funds were utilized to repay a line of credit assumed from the Oak Park River Forest acquisition, which was completed on April 30, 2019. The following March 31, December 31, 2019 2018 Federal Reserve Bank of Chicago discount window line $ 314,229 $ 293,613 Available federal funds lines 85,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Junior Subordinated Debentures	Note 14—Junior Subordinated Debentures At March 31, 2019 and December 31, 2018, the Name of Trust Aggregate Principal Amount March 31, 2019 Aggregate Principal Amount December 31, 2018 Stated Maturity Contractual Rate at March 31, 2019 Interest Rate Spread Metropolitan $ 35,000 $ 35,000 March 5.40 % Three-month LIBOR + 2.79% RidgeStone Capital Trust I 1,500 1,500 June 30, 2033 6.38 % Five-year LIBOR + 3.50% First Evanston Bancorp Trust I 10,000 10,000 March 15, 2035 4.39 % Three-month LIBOR + 1.78% Total liability, at par 46,500 46,500 Discount (9,588 ) (9,732 ) Total liability, at carrying value $ 36,912 $ 36,768 In 2004, the As part of the Ridgestone acquisition, the Company assumed the obligations to RidgeStone Capital Trust I of $1.5 million in principal amount, which was formed for the issuance of trust preferred securities. Beginning on June 30, 2008, the interest rate reset to the five-year LIBOR plus 3.50% (6.38% at March 31, 2019 and December 31, 2018), which is in effect until June 30, 2023 and updated every five years. Interest is paid on a quarterly basis. The Company has the right to redeem the debentures, in whole or in part, on any interest payment date on or after June 30, 2008. As part of the First Evanston acquisition, the Company assumed the obligations to First Evanston Bancorp Trust I of $10.0 million in principal amount, which was formed for the issuance of trust preferred securities. Refer to Note 3—Acquisition of a Business for additional information. Beginning on March 15, 2010, the interest rate reset to the three-month LIBOR plus 1.78% (4.39% and 4.57% at March 31, 2019 and December 31, 2018, respectively), which is in effect until the debentures mature in 2035. Interest is paid on a quarterly basis. The Company has the right to redeem the debentures, in whole or in part, on any interest payment date on or after March 2010. The Company has the option to defer interest payments on the debentures from time to time for a period not to exceed five consecutive years. Accrued The Trusts

Commitments and Contingent Liab

Commitments and Contingent Liabilities	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Note 15—Commitments Legal —I n th e ordinar y cours e o f business , th e Compan y an d Ban k hav e various outstandin g commitment s an d contingen t liabilitie s tha t ar e no t recognize d i n th e accompanyin g consolidated financia l statements . I n addition , th e Compan y ma y b e a defendan t i n certai n claim s an d lega l action s arisin g i n the ordinar y cours e o f business . I n th e opinio n o f management , afte r consultatio n wit h lega l counsel , th e ultimate dispositio n o f thes e matter s i s currentl y no t expecte d t o hav e a materia l advers e effec t o n th e Company’s Consolidated Financial Statements. Operating s —The Company has entered into various operating lease agreements primarily for facilities and land on which banking facilities are located. Certain lease agreements have renewal options at the end of the original lease term and certain lease agreements have escalation clauses in the rent payments. The minimum Minimum Commitments 2019 $ 2,714 2020 3,221 2021 2,961 2022 1,954 2023 1,012 Thereafter 3,069 Total $ 14,931 The Company’s During t C In June 2018, the Company accrued $8.1 million in data processing expense primarily related to contract termination with its core service provider in anticipation of a future system conversion Commitments t —The Company is party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit. Those instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the Consolidated Statements of Financial Condition. The contractual or notional amounts of those instruments reflect the extent of involvement the Company has in particular classes of financial instruments. The Company’s exposure The following March 31, December 31, 2019 2018 Fixed Rate Variable Rate Fixed Rate Variable Rate Commitments to extend credit $ 80,916 $ 875,341 $ 74,099 $ 928,991 Letters of credit 1,750 34,154 1,982 34,071 Total $ 82,666 $ 909,495 $ 76,081 $ 963,062 Commitments Letters Commitments

Fair Value Measurement

Fair Value Measurement	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 16—Fair Value Measurement Fair These types Level 1 —Quoted prices in active markets for identical assets or liabilities. Level 2 —Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-derived valuations whose inputs are observable or whose significant value drivers are observable. Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the asset or liability. Unobservable inputs are used to measure fair value to the extent that observable inputs are not available. The Company’s own data used to develop unobservable inputs may be adjusted for market considerations when reasonably available. The The Company used the Securities e —The Company obtains fair value measurements from an independent pricing service. Management reviews the procedures used by the third party, including significant inputs used in the fair value calculations. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. When market quotes are not readily accessible or available, alternative approaches are utilized, such as matrix or model pricing. The Company’s methodology for pricing non-rated bonds focuses on three distinct inputs: equivalent rating, yield and other pricing terms. To determine the rating for a given non-rated municipal bond, the Company references a publicly issued bond by the same issuer if available as well as other additional key metrics to support the credit worthiness. Typically, pricing for these types of bonds would require a higher yield than a similar rated bond from the same issuer. A reduction in price is applied to the rating obtained from the comparable bond, as the Company believes if liquidated, a non-rated bond would be valued less than a similar bond with a verifiable rating. The reduction applied by the Company is one notch lower (i.e. a “AA” rating for a comparable bond would be reduced to “AA-” for the Company’s valuation). In 2018 and 2017, all of the ratings derived by the Company were “BBB” or better with and without comparable bond proxies. The fair value measurement of municipal bonds is sensitive to the rating input, as a higher rating typically results in an increased valuation. The remaining pricing inputs used in the bond valuation are observable. Based on the rating determined, the Company obtains a corresponding current market yield curve available to market participants. Other terms including coupon, maturity date, redemption price, number of coupon payments per year, and accrual method are obtained from the individual bond term sheets. Equity and other securities —The Company utilizes the same fair value measurement methodology for equity and other securities as detailed in the securities available-sale portfolio above. Servicing s —Fair value is based on a loan-by-loan basis taking into consideration the original term to maturity, the current age of the loan and the remaining term to maturity. The valuation methodology utilized for the servicing assets begins with generating future cash flows for each servicing asset, based on their unique characteristics and market-based assumptions for prepayment speeds. The present value of the future cash flows are then calculated utilizing market-based discount rate assumptions. Derivative s —Interest rate derivatives are valued by a third party, using models that primarily use market observable inputs, such as yield curves, and are validated by comparison with valuations provided by the respective counterparties. Derivative financial instruments are included in other assets and other liabilities in the Consolidated Statements of Financial Condition. The following Fair Value Measurements Using March 31, 2019 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 57,387 $ 57,387 $ — $ — U.S. Government agencies 187,502 — 187,502 — Obligations of states, municipalities, and political subdivisions 82,567 — 82,372 195 Mortgage-backed securities; residential Agency 340,484 — 340,484 — Non-Agency 131,666 — 131,666 — Mortgage-backed securities; commercial Agency 97,813 — 97,813 — Non-Agency 30,835 — 30,835 — Corporate securities 36,299 — 36,299 — Equity and other securities, at fair value Mutual funds 2,882 2,882 — — Equity securities 4,334 — 3,639 695 Servicing assets 19,534 — — 19,534 Derivative assets 9,788 — 9,788 — Financial liabilities Derivative liabilities 5,984 — 5,984 — Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 52,667 $ 52,667 $ — $ — U.S. Government agencies 186,498 — 186,498 — Obligations of states, municipalities, and political subdivisions 60,233 — 60,038 195 Mortgage-backed securities; residential Agency 272,963 — 272,963 — Non-Agency 83,621 — 83,621 — Mortgage-backed securities; commercial Agency 90,434 — 90,434 — Non-Agency 30,458 — 30,458 — Corporate securities 34,173 — 34,173 — Other securities 6,609 2,844 3,074 691 Servicing assets 19,693 — — 19,693 Derivative assets 10,740 — 10,740 — Financial liabilities Derivative liabilities 4,243 — 4,243 — The T he Company has purchased, and acquired through a business combination, privately-issued municipal securities that are categorized as Level 3. These municipal securities are bonds issued for municipal government entities located in the Chicago metropolitan area and are privately placed, non-rated bonds without Committee on Uniform Security Identification Procedures numbers. The Company did not have any transfers three months ended and 2018 The following table presents additional information about financial assets measured at fair value on recurring basis for which the Company used significant unobservable inputs (Level 3): Three Months Ended March 31, 2019 2018 2019 2018 Investment Securities Servicing Assets Balance, beginning of period $ 886 $ 1,052 $ 19,693 $ 21,400 Additions, net — — 1,102 2,102 Amortization 1 1 — — Change in unrealized gain — 14 — — Change in fair value 3 — (1,261 ) (1,887 ) Balance, end of period $ 890 $ 1,067 $ 19,534 $ 21,615 The following Financial Instruments Valuation Technique Unobservable Inputs Range of Inputs Weighted Average Range Impact to Valuation from an Increased or Higher Input Value Obligations of states, municipalities, and political obligations Discounted Probability of default 2.4% 2.4% Decrease Single issuer trust preferred Discounted cash flow Probability of default 4.9%—5.4% 5.9% Decrease Servicing assets Discounted cash flow Prepayment speeds 2.1%—17.7% 11.9% Decrease Discount rate 7.1%—21.8% 14.3% Decrease Expected weighted average loan life 0.1—10.5 years 5.0 years Increase The Company used the Impaired ) —Impaired loans, other than those existing on the date of a business acquisition, are primarily carried at the fair value of the underlying collateral, less estimated costs to sell, if the loan is collateral dependent. Valuations of impaired loans that are collateral dependent are supported by third party appraisals in accordance with the Bank’s credit policy. Other valuation methods include analysis of discounted cash flows, which measures the present value of expected future cash flows discounted at the loan’s effective interest rate. Impaired loans that are not collateral dependent are not material. Assets e —Assets held for sale consist of former branch locations and real estate previously purchased for expansion. Assets are considered held for sale when management has approved to sell the assets following a branch closure or other events. The properties are being actively marketed and transferred to assets held for sale based on the lower of carrying value or its fair value, less estimated costs to sell. Other d —Certain assets held within other real estate owned represent real estate or other collateral that has been adjusted to its estimated fair value, less cost to sell, as a result of transferring from the loan portfolio at the time of foreclosure or repossession and based on management’s periodic impairment evaluation. From time to time, non-recurring fair value adjustments to other real estate owned are recorded to reflect partial write-downs based on an observable market price or current appraised value of property. Adjustments Fair Value Measurements Using March 31, 2019 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 15,951 $ — $ — $ 15,951 Residential real estate 2,026 — — 2,026 Construction, land development, and other land — — — — Commercial and industrial 18,262 — — 18,262 Assets held for sale 13,596 — — 13,596 Other real estate owned 4,799 — — 4,799 Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 9,792 $ — $ — $ 9,792 Residential real estate 2,076 — — 2,076 Construction, land development, and other land — — — — Commercial and industrial 17,397 — — 17,397 Installment and other — — — — Assets held for sale 14,489 — — 14,489 Other real estate owned 5,314 — — 5,314 The following Cash and cash equivalent s —For these short-term instruments, the carrying amount is a reasonable estimate of fair value. Securities y —The Company obtains fair value measurements from an independent pricing service. Management reviews the procedures used by the third party, including significant inputs used in the fair value calculations. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. When market quotes are not readily accessible or available, alternative approaches are utilized, such as matrix or model pricing. Restricted k —The fair value has been determined to approximate cost. Loans held for — The fair value of loans held for sale are based on quoted market prices, where available, and determined by discounted estimated cash flows using interest rates approximating the Company’s current origination rates for similar loans adjusted to reflect the inherent credit risk. Loan —For certain variable rate loans that reprice frequently and with no significant changes in credit risk, fair value is estimated at carrying value. The fair value of other types of loans is estimated by discounting future cash flows, using current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities. Deposits —The fair value of demand deposits, savings accounts, and certain money market deposits is the amount payable on demand at the reporting date. The fair value of fixed-maturity certificates of deposit is estimated by discounting future cash flows, using rates currently offered for deposits of similar remaining maturities. Federal —The fair value of FHLB advances is estimated by discounting the agreements based on maturities using rates currently offered for FHLB advances of similar remaining maturities adjusted for prepayment penalties that would be incurred if the borrowings were paid off on the measurement date. Securities e —The carrying amount approximates fair value due to maturities of less than ninety days. Junior subordinated debenture s —The fair value of junior subordinated debentures, in the form of trust preferred securities, is determined using rates currently available to the Company for debt with similar terms and remaining maturities. Accrued interest —The carrying amount approximates fair value. Commitments t —The fair values of these off-balance sheet commitments to extend credit and commercial and letters of credit are not considered practicable to estimate because of the lack of quoted market prices and the inability to estimate fair value without incurring excessive costs. The estimated March 31, December 31, Fair Value 2019 2018 Hierarchy Level Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets Cash and due from banks 1 $ 50,026 $ 50,026 $ 30,190 $ 30,190 Interest bearing deposits with other banks 2 31,971 31,971 91,670 91,670 Securities held-to-maturity 2 4,425 4,431 99,266 97,739 Other restricted stock 2 19,202 19,202 19,202 19,202 Loans held for sale 3 510 563 19,827 21,654 Loans and lease receivables, net (less impaired loans at fair value (1) 3 3,496,662 3,401,501 3,447,160 3,407,652 Accrued interest receivable 3 11,974 11,974 10,863 10,863 Financial liabilities Non-interest-bearing deposits 2 1,163,255 1,163,255 1,192,873 1,192,873 Interest-bearing deposits 2 2,645,261 1,268,458 2,557,043 2,554,329 Accrued interest payable 2 4,390 4,390 3,484 3,484 Line of credit 2 — — — — Federal Home Loan Bank advances 2 425,000 425,000 425,000 425,000 Securities sold under repurchase agreement 2 34,369 34,369 34,166 34,166 Junior subordinated debentures 3 36,912 42,292 36,768 42,351 (1) In accordance with the prospective adoption of ASU 2016-01, the fair value of loans and lease receivables, net (less impaired loans at fair value) as of March 31, 2019 was measured using an exit price notion. The fair value as of December 31, 2018 was measured using an entry price notion.

Derivative Instruments and Hedg

Derivative Instruments and Hedge Activities	3 Months Ended
	Mar. 31, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedge Activities	Note 17—Derivative Instruments and Hedge Activities The Company recognizes derivative financial instruments at fair value regardless of the purpose or intent for holding the instrument. The Company records derivative assets and derivative liabilities on the Consolidated Statements of Financial Condition within accrued interest receivable and other assets and accrued interest payable and other liabilities, respectively. The following tables present the fair value of the Company’s derivative financial instruments and classification on the Consolidated Statements of Financial Condition as of March 31, 2019 and December 31, 2018: March 31, 2019 December 31, 2018 Fair Value Fair Value Notional Amount Other Assets Other Liabilities Notional Amount Other Assets Other Liabilities Derivatives designated as hedging instruments Interest rate swaps designated as cash flow hedges $ 250,000 $ 4,160 $ — $ 250,000 $ 6,699 $ — Derivatives not designated as hedging instruments Other interest rate derivatives 324,793 5,628 5,976 294,545 4,041 4,237 Other credit derivatives 4,504 — 8 4,424 — 6 Total derivatives $ 579,297 $ 9,788 $ 5,984 $ 548,969 $ 10,740 $ 4,243 Interest rate swaps designated as cash flow hedges —Cash flow hedges of interest payments associated with certain FHLB advances had notional amounts totaling $250.0 million as of March 31, 2019 and December 31, 2018. The Company assesses the effectiveness of each hedging relationship by comparing the changes in fair value of the derivative hedging instrument with the changes in fair value of the designated hedged transactions. Interest recorded on these swap transactions reduced FHLB interest expense by $705,000 The following table reflects the cash flow hedges as of March 31, 2019: Notional amounts $ 250,000 Derivative assets fair value 4,160 Derivative liabilities fair value — Weighted average pay rates 1.67 % Weighted average receive rates 2.82 % Weighted average maturity 2.9 years The following table reflects the net gains (losses) recorded in accumulated other comprehensive income (loss) and the Consolidated Statements of Operations relating to the cash flow derivative instruments for the three months ended: March 31, 2019 March 31, 2018 Amount of Gain Recognized in OCI Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Amount of Gain Recognized in OCI Amount of Gain Reclassified from OCI to Income as an Increase to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Interest rate swaps $ (1,817 ) $ 705 $ — $ 4,070 $ 61 $ — Other interest rate derivatives —The total combined notional amount was $324.8 million as of March 31, 2019 with maturities ranging from April 2020 to January 2030. The fair values of the interest rate derivative agreements are reflected in other assets and other liabilities with corresponding gains or losses reflected in non-interest income. During the three months ended March 31, 2019, there were $325,000 of transaction fees included in other non-interest income, related to these derivative instruments. During the three months ended March 31, 2018, there were no transaction fees related to these derivative instruments. The following table reflects other interest rate derivatives as of March 31, 2019: Notional amounts $ 324,793 Derivative assets fair value 5,628 Derivative liabilities fair value 5,976 Weighted average pay rates 4.82 % Weighted average receive rates 4.64 % Weighted average maturity 5.9 years Other credit derivatives— The total notional amount was $4.5 million and $4.4 million as of March 31, 2019 and December 31, 2018, respectively. The fair value of the other credit derivatives are reflected in other liabilities with corresponding gains or losses reflected in non-interest income. The credit valuation adjustment (“CVA”) related to the other credit derivatives resulted in a decrease to other non-interest income during the three months ended March 31, 2019 and 2018 of $1,000 and $3,000, respectively. There were no transaction fees included in non-interest income related to these derivative instruments during the three months ended March 31, 2019, and there was $26,000 of transaction fees during the three months ended March 31, 2018. The Company has entered into risk participation agreements with counterparty banks to assume a portion of the credit risk related to borrower transactions. The credit risk related to these other credit derivatives is managed through the Company’s loan underwriting process. Credit risk —Derivative instruments are inherently subject to market risk and credit risk. Market risk is associated with changes in interest rates and credit risk relates to the Company’s risk of loss when the counterparty to a derivative contract fails to perform according to the terms of the agreement. Market and credit risks are managed and monitored as part of the Company’s overall asset-liability management process. The credit risk related to derivatives entered into with certain qualified borrowers is managed through the Company’s loan underwriting process. The Company’s loan underwriting process also approves the Bank’s swap counterparty used to mirror the borrowers’ swap. The Company has a bilateral agreement with each swap counterparty that provides that fluctuations in derivative values are to be fully collateralized with either cash or securities. The CVA is a fair value adjustment to the derivative to account for this risk. During the three months ended March 31, 2019, the CVA resulted in a decrease to non-interest income of $151,000. During three months ended March 31, 2018, the CVA resulted in an increase to non-interest income of $27,000. The Company has agreements with its derivative counterparties that contain a cross-default provision under which if the Company defaults on any of its indebtedness, including default where repayment of the indebtedness has not been accelerated by the lender, then the Company could also be declared in default on its derivative obligations. The Company also has agreements with certain derivative counterparties that contain a provision where if the Company fails to maintain its status as a well or adequately capitalized institution, then the counterparty could terminate the derivative positions and the Company would be required to settle its obligations resulted in a net asset position. T he Company records interest rate derivatives subject to master netting agreements at their gross value and does not offset derivative asset and liabilities on the Consolidated Statements of Financial Condition. The table below summarizes the Company’s interest rate derivatives and offsetting positions as of: March 31, 2019 December 31, 2018 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 9,788 $ 5,984 $ 10,740 $ 4,243 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 9,788 $ 5,984 $ 10,740 $ 4,243 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (3,852 ) (3,852 ) (2,823 ) (2,823 ) Collateral posted (5,433 ) (2,265 ) (7,917 ) (1,317 ) Net credit exposure $ 503 $ (133 ) $ — $ 103

Share-Based Compensation

Share-Based Compensation	3 Months Ended
	Mar. 31, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	Note 18 – Share-Based Compensation In June 2017, the Company adopted the 2017 Omnibus Incentive Compensation Plan (the “Omnibus Plan”) in connection with our IPO. The Omnibus Plan provides for the grant of stock options, stock appreciation rights, restricted stock, restricted stock units, dividend equivalent rights and other equity-based, equity-related or cash-based awards. A total of 1,550,000 shares of our common stock have been reserved for issuance under the Omnibus Plan. As of March 31, 2019, there were 1,359,045 shares available for future grants under the Omnibus Plan. On July 6, 2017, in conjunction with the completion of the IPO, the Company granted 58,900 restricted shares of the Company’s common stock to certain key employees, pursuant to the Omnibus Plan. The restricted shares will cliff vest on the third anniversary of the grant date, subject to continued employment. A total of 11,898 restricted shares were also granted during the year ended December 31, 2017 in connection with the recruitment of employees. These restricted shares vest ratably over a four year period. During 2018, the Company granted 131,157 shares of restricted common stock, par value $0.01 per share. Of this total, 102,559 restricted shares will vest ratably over four years on each anniversary of the grant date, 15,165 restricted shares will vest ratably over three years on each anniversary of the grant date, and 2,268 restricted shares will vest on the first anniversary of the grant date, all subject to continued employment. In addition, 11,165 performance-based restricted shares were included in the 2018 grant. The number of shares which may be earned under the award is dependent upon the Company’s return on average assets over a three-year period ending December 31, 2020, measured in 2018 against the Company’s internal targets and for 2019 and 2020 against a peer group consisting of publicly-traded bank holding companies ranging in asset size from 50% to 200% of the Company’s total assets. Under the award, 25% of the shares will be earned at threshold performance, 100% will be earned at target and 50th percentile performance, and up to 125% of the shares with above target and 75th percentile performance. Any earned performance shares will vest on the third anniversary of the grant date. During April 2019, the Company granted 127,115 shares of restricted common stock, par value $0.01 per share. Of this total, 84,482 restricted shares will vest ratably over four years on each anniversary of the grant date, 20,975 restricted shares will vest ratably over three years on each anniversary of the grant date, and 683 restricted shares will vest on the first anniversary of the grant date, all subject to continued employment. In addition, 20,975 performance-based restricted shares were included in the April 2019 grant. The number of shares which may be earned under the award is dependent upon the Company’s return on average assets, weighted equally, over a three-year period ending December 31, 2021, measured against a peer group consisting of publicly-traded bank holding companies. Results will be measured cumulatively at the end of the three years. Any earned shares will vest on the third anniversary of the grant date. On April 30, 2018, the Company completed the acquisition of Oak Park River Forest. The Company expects to make a cash payment of $4.2 million for 35,870 outstanding options to Oak Park River Forest stockholders who elected to receive a cash payment in lieu of converting the options to the Company’s plan. The payment is expected to be completed by May 15, 2019. The following table discloses the changes in restricted shares for the three months ended March 31, 2019: Omnibus Plan Number of Shares Weighted Average Grant Date Fair Value Beginning balance, January 1, 2019 196,480 $ 21.66 Granted — — Vested (6,134 ) 20.69 Forfeited (8,500 ) 21.03 Ending balance outstanding at March 31, 2019 181,846 $ 21.72 A total of 6,134 restricted shares vested during the three months ended March 31, 2019. The fair value of restricted shares that vested during the three months ended March 31, 2019 was $102,000. A total of 2,975 restricted shares vested during the year ended December 31, 2018. The fair value of restricted shares that vested during the year ended December 31, 2018 was $62,000. The Company recognizes share-based compensation based on the estimated fair value of the restricted stock at the grant date. Share-based compensation expense is included in non-interest expense in the Consolidated Statements of Operations. The following table summarizes restricted stock compensation expense for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Total share-based compensation - restricted stock $ 353 $ 112 Income tax benefit 98 31 Unrecognized compensation expense 2,675 1,114 Weighted-average amortization period remaining 2.7 years 2.6 years The fair value of the unvested restricted stock awards at March 31, 2019 was $3.4 million. The Company maintained a nonqualified, share-based, stock option plan adopted prior to recapitalization (“MBG Plan”). There were no options granted or exercised under this plan during the year ended December 31, 2017. At the time of the Company’s reincorporation in Delaware, in June 2017, the Board of Directors cancelled the MBG Plan and all the respective outstanding options were cancelled. In October 2014, the Company adopted the Byline Bancorp, Inc. Equity Incentive Plan (“BYB Plan”). The maximum number of shares available for grants under this plan was 2,476,122 shares. During 2016 and 2015, the Company granted options to purchase 212,400 and 1,634,568 shares, respectively, under this plan. The Company did not grant any stock options during the year ended December 31, 2017. In June 2017, the Board of Directors terminated the BYB Plan and no future grants can be made under this plan. Options to purchase a total of 1,588,872 shares remain outstanding under the BYB Plan at March 31, 2019. The types of stock options granted under the BYB Plan were Time Options and Performance Options. The exercise price of each option is equal to the fair value of the stock as of the date of grant. These option awards have vesting periods ranging from one to five years and have 10-year contractual terms. Stock volatility was computed as the average of the volatilities of peer group companies. The vesting of Time Options is conditional based on completion of service. Performance Options have conditional vesting based on either performance targets or market performance. Certain Performance Options’ performance goals will be satisfied (in whole or in part) if the Bank achieves various performance targets such as profitability, asset quality, and conditional based on market performance, as outlined in the BYB Plan. Each of the performance goals identified are measured for achievement (or failure to achieve) independent of each other. In October 2017, the Board of Directors determined that the Performance Option goals were satisfied, in whole, and these Performance Options converted to Time Options. As a result of the previous completion of service, 414,894 performance options vested on October 3, 2017. The fair values of the stock options were determined using the Black-Scholes-Merton model for Time Options and a Monte Carlo simulation model for Performance Options. The following table discloses the activity in shares subject to options and the weighted average exercise prices, in actual dollars, for the three months ended March 31, 2019: BYB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 1,598,872 $ 11.84 $ 7,713 6.6 Exercised (10,000 ) 16.25 $ 32 Forfeited — Ending balance outstanding at March 31, 2019 1,588,872 $ 11.81 $ 10,601 6.3 Exercisable at March 31, 2019 1,490,572 $ 11.52 $ 10,382 6.3 A total of 10,000 stock options were exercised during the three months ended March 31, 2019. During the three months ended March 31, 2019, proceeds from the exercise of stock options were $163,000 and related tax benefit was $9,000. A total of 148,748 stock options were exercised during the year ended December 31, 2018. During the year ended December 31, 2018, proceeds from the exercise of stock options were $1.7 million and related tax benefit was $449,000. No stock options vested during the three months ended March 31, 2019. The Company recognizes share-based compensation based on the estimated fair value of the option at the grant date. Forfeitures are estimated based upon industry standards. Share-based compensation expense is included in non-interest expense in the Consolidated Statements of Operations. The following table summarizes stock option compensation expense for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Total share-based compensation - stock options $ 33 $ 229 Income tax benefit 9 64 Unrecognized compensation expense - stock options 113 499 Weighted-average amortization period remaining 0.8 years 1.1 years Pursuant to the terms of the Merger Agreement, upon the Effective Time, each outstanding First Evanston Option held by a participant in the First Evanston Bancorp, Inc. Stock Incentive Plan (the “FEB Plan”) ceased to represent a right to acquire shares of First Evanston common stock and was assumed and converted automatically into a fully vested and exercisable adjusted option to purchase shares of Byline common stock (each an “Adjusted Option”). In accordance with the Merger Agreement, the number of shares of Byline common stock to which each such Adjusted Option relates is equal to the product (rounded down to the nearest whole share of Byline common stock) of: (a) the number of shares of First Evanston common stock subject to the First Evanston Option immediately prior to May 31, 2018, multiplied by (ii) 4.725. Each Adjusted Option has an exercise price per share of Byline common stock equal to the quotient (rounded up to the nearest whole cent) of (x) the per share exercise price of such First Evanston Option immediately prior to May 31, 2018, divided by (y) 4.725. The description of the conversion process is based on, and qualified by, the Merger Agreement. The following table discloses the activity in shares subject to options under the FEB Plan and the weighted average exercise prices, in actual dollars, for the three months ended March 31, 2019: FEB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 624,383 $ 11.31 $ 3,339 5.2 Granted — Expired — Exercised (40,662 ) 11.63 $ 316 Forfeited — Ending balance outstanding at March 31, 2019 583,721 $ 11.29 $ 4,197 4.9 Exercisable at March 31, 2019 583,721 $ 11.29 $ 4,197 4.9 A total of 40,662 stock options were exercised during the three months ended March 31, 2019. During the three months ended March 31, 2019, proceeds from the exercise of stock options were $473,000 and related tax benefit was $88,000. A total of 56,404 stock options were exercised during the year ended December 31, 2018. During the year ended December 31, 2018, proceeds from the exercise of stock options were $601,000 and related tax benefit was $168,000. All shares of restricted performance shares of First Evanston common stock (“restricted stock”) that were previously issued under and held by Participants in the FEB Plan prior to the Merger were converted into the right to receive the per share merger consideration in connection with the Merger and pursuant to the Merger Agreement. Accordingly, no shares of First Evanston restricted stock remain outstanding under the FEB Plan.

Earnings per Share

Earnings per Share	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Earnings per Share	Note 19—Earnings per Share A reconciliation of the numerators and denominators for earnings per common share computations is presented below. Incremental shares represent outstanding stock options for which the exercise price is less than the average market price of the Company’s common stock during the periods presented. Options to purchase 2,172,593 and 1,696,270 shares of common stock were outstanding as of March 31, 2019 and 2018, respectively. There were 181,846 and 70,798 restricted stock awards outstanding at March 31, 2019 and 2018, respectively. The following represent the calculation of basic and diluted earnings per share for the periods presented: Three Months Ended March 31, 2019 2018 Net income $ 12,597 $ 6,768 Less: Dividends on preferred shares 196 193 Net income available to common stockholders $ 12,401 $ 6,575 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 36,169,477 29,291,179 Incremental shares 707,097 622,454 Weighted-average common stock outstanding (dilutive) 36,876,574 29,913,633 Basic earnings per common share $ 0.34 $ 0.22 Diluted earnings per common share $ 0.34 $ 0.22

Stockholders' Equity

Stockholders' Equity	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Stockholders' Equity	Note 20—Stockholders’ Equity A summary of the Company’s preferred and common stock at March 31, 2019 and December 31, 2018 is as follows: March 31, December 31, 2019 2018 Series B 7.5% fixed to floating non-cumulative perpetual preferred stock Par value $ 0.01 $ 0.01 Shares authorized 50,000 50,000 Shares issued 10,438 10,438 Shares outstanding 10,438 10,438 Common stock, voting Par value $ 0.01 $ 0.01 Shares authorized 150,000,000 150,000,000 Shares issued 36,398,144 36,343,239 Shares outstanding 36,398,144 36,343,239 During 2016, the Company authorized and issued Series B 7.50% fixed-to-floating non-voting, noncumulative perpetual preferred stock with a liquidation preference of $1,000 per share, plus the amount of unpaid dividends, if any, which is redeemable at the Company’s option on or after March 31, 2022. Holders of Series B Preferred Stock do not have any rights to convert such stock into shares of any other class of capital stock of the Company. Holders of Series B Preferred Stock are entitled to receive a fixed dividend of 7.50% per annum from the original issue date through December 30, 2021, after which the dividend is paid at a floating rate of three-month LIBOR plus 5.41% per annum. The Company Series B Preferred Stock is included in Tier 1 capital for regulatory capital purposes and is redeemable at the option of the Company at a redemption price of $1,000 per share, plus any declared and unpaid dividends (i) in whole or part on any dividend payment date on or after March 31, 2022, and (ii) in whole but not in part prior to March 31, 2022, within 90 days following a regulatory event, as defined in the Certificate of Designations of the Company Series B Preferred Stock. The Company must receive approval of the Federal Reserve Board prior to any redemption of the Company Series B Preferred Stock. For the three months ended March 31, 2019, the Company declared and paid dividends on the Series B preferred stock of $196,000, compared to $193,000 for the three months ended March 31, 2018.

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	3 Months Ended
	Mar. 31, 2019
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	Note 21—Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) The following table summarizes the changes in accumulated other comprehensive income (loss) for the three months ended March 31, 2019 and 2018: (dollars in thousands) Unrealized Gains (Losses) on Cash Flow Hedges Unrealized (Losses) on Available-for -Sale Securities Total Accumulated Other Comprehensive Income (Loss) Balance, January 1, 2018 $ 2,913 $ (8,000 ) $ (5,087 ) Reclassification of certain income tax effects from accumulated other comprehensive income 687 (1,450 ) (763 ) Other comprehensive income (loss), net of tax 2,893 (6,457 ) (3,564 ) Balance, March 31, 2018 $ 6,493 $ (15,907 ) $ (9,414 ) Balance, January 1, 2019 $ 4,763 $ (14,261 ) $ (9,498 ) Adoption of ASU 2016-01 — (1,440 ) (1,440 ) Other comprehensive income (loss), net of tax (1,820 ) 6,339 4,519 Balance, March 31, 2019 $ 2,943 $ (9,362 ) $ (6,419 )

Basis of Presentation (Policies

Basis of Presentation (Policies)	3 Months Ended
	Mar. 31, 2019
Accounting Policies [Abstract]
Basis of Presentation	These unaudited interim condensed consolidated financial statements include the accounts of Byline Illinois state chartered These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). In preparing these financial statements, the Company has evaluated events and transactions subsequent to March 31, 2019 for potential recognition or disclosure. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information in footnote disclosures normally included in financial statements prepared in accordance with GAAP has been condensed or omitted pursuant to the rules and regulations of the SEC and the accounting standards for interim financial statements. These financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Consolidated Financial Statements for the years ended December 31, 2018, 2017, and 2016. In accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 855, “Subsequent Events,” the Company’s management has evaluated subsequent events for potential recognition or disclosure through the date of the issuance of these consolidated financial statements. The Company has one reportable segment. The Company’s chief operating decision maker evaluates the operations of the Company using consolidated information for purposes of allocating resources and assessing performance. Therefore, segments disclosures are not required. On October 17, 2018, the Company entered a definitive merger agreement with Oak Park River Forest Bankshares, Inc. (“Oak Park River Forest”), the parent company of Community Bank of Oak Park River Forest, to which the Company will acquire Oak Park River Forest through the merger of Oak Park River Forest with and into the Company, followed immediately by the merger of Community Bank of Oak Park River Forest with and into Byline Bank. On April 30, 2019, Byline completed its acquisition of Oak Park River Forest. Under the terms of the merger agreement, each share of Oak Park River Forest's common stock was converted into the right to receive 7.9321 shares of Byline common stock and $33.375 in cash. The value of the total merger consideration at closing was approximately $39.6 million. No other subsequent events were identified that would have required a change to the consolidated financial statements or disclosure in the notes to the consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity.
Accounting Pronouncements Recently Adopted or Issued	The following reflect recent accounting pronouncements that have been adopted or are pending adoption by the Company. As the Company qualifies as an emerging growth company and has elected the extended transition period for complying with new or revised accounting pronouncements, it is not subject to new or revised accounting standards applicable to public companies during the extended transition period. The accounting pronouncements pending adoption below reflect effective dates for the Company as an emerging growth company with the extended transition period. Adopted Accounting Pronouncements Revenue from Contracts with Customers In May 2014, FASB issued Accounting Standards Update (“ASU”) No. 2014-09, deferred by ASU No. 2015-14 and clarifying standards, Revenue from Contracts with Customers , which creates Topics 606 and 610 and supersedes Topic 605, Revenue Recognition . The core principle of Topic 606 is that an entity recognizes 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 or services. In April 2016, FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing . The amendments in this ASU clarify the following two aspects of Topic 606: (1) identifying performance obligations and (2) licensing implementation guidance, while retaining the related principles for those areas. In May 2016, FASB issued ASU No. 2016-12, Narrow-Scope Improvements and Practical Expedients , amending ASC Topic 606, Revenue from Contracts with Customers . The amendments in this ASU affect only several narrow aspects of Topic 606. In November 2017, FASB issued ASU No. 2017-14, amending ASC Topic 606, Revenue from Contracts with Customers . The ASU amends the codification to incorporate additional previously issued guidance from the SEC. The SEC issued SAB 116 to bring existing SEC staff guidance into conformity with the FASB’s adoption of and amendments to ASC Topic 606. In general, the new guidance requires companies to use more judgment and make more estimates than under current guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The new authoritative guidance was initially effective for reporting periods after January 1, 2017 but was deferred to January 1, 2018. Given our emerging growth status, the Company adopted this new guidance on January 1, 2019 using the full retrospective method, meaning the standard is applied to all periods presented in the financial statements with the cumulative effect of initially applying the standard recognized at the beginning of the earliest period presented. The majority of the Company’s revenue streams, including interest and dividend income, servicing fees, and gains on sales of loans and investments, are outside the scope of Topic 606. Revenue streams reported as fees and service charges on deposits, ATM and interchange fees, and wealth management and trust income are within the scope of Topic 606. The Company applied the requirements of Topic 606 to the revenue streams that are within its scope. The adoption of Topic 606 did not result in any changes in the either timing or amount of recognized; there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition. However, the presentation of certain costs associated with our ATM and debit card income were offset against ATM and interchange income. This change in presentation resulted in $346,000 of expenses for the three months ended March 31, 2019 being netted against ATM and interchange fees and reported in non-interest income instead of as other non-interest expense in non-interest expense. In addition, to conform to the current period presentation, $305,000 of related expenses for the three months ended March 31, 2018 were reclassified from other non-interest expense in non-interest expense to being netted against ATM and interchange fees in non-interest income. The Company elected to apply the practical expedient and therefore does not disclose information about remaining performance obligations that have an original expected term of one year or less and allows the Company to expense costs related to obtaining a contract as incurred when the amortization period would have been one year or less. The Company adopted ASU 2014-09 using the full retrospective approach. The following table presents the impact of adopting the new revenue standard on our Consolidated Statements of Operations for the periods presented (in thousands): For the Three Months Ended For the Three Months Ended March 31, 2019 March 31, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 717 $ 1,063 $ (346 ) $ 913 $ 1,218 $ (305 ) Non-interest expense: Other non-interest expense $ 2,839 $ 3,185 $ (346 ) $ 1,752 $ 2,057 $ (305 ) Fees and service charges on deposits: Fees and service charges on deposits include transaction and non-transaction based deposit fees. Transaction based fees on deposit accounts are charged to deposit customers for specific services provided to the customer. These fees include such items as wire fees, official check fees, and overdraft fees. These are contracts specific to each individual transaction and do not extend beyond the individual transaction. The performance obligation is completed and the fees are recognized at the time the specific transactional service is provided to the customer. Non-transactional deposit fees are typically monthly account maintenance fees charged on deposit accounts. These are day-to-day contracts that can be canceled by either party without notice. The performance obligation is satisfied and the fees are recognized on a monthly basis after the service period is completed. ATM and interchange fees: ATM fees represent fees earned when a foreign debit or ATM card is used in a Byline Bank ATM. These fees are assessed and paid at the time of each transaction as the performance obligation is satisfied, which is at the point in time that the transaction is performed and approved. Interchange fees represent fees earned when a debit card issued by the Bank is used to purchase goods or services at a merchant. The merchant's bank pays the Bank a default interchange rate set by MasterCard on a transaction by transaction basis. Interchange fees are assessed as the performance obligation is satisfied, which is at the point in time the card transaction is authorized. The performance obligation is satisfied and the fees are earned when the cost of the transaction is charged to the Bank cardholders’ card. Direct expenses associated with ATM and debit cards are recorded as a net reduction against the ATM and interchange income. Wealth management and trust income Wealth management and trust income represents fees earned by the Bank for discretionary investment management, trust administration, fiduciary and/or custody services rendered. Fees vary and are based on a contract with the customer. Fee income is determined as a percentage of assets under management and is recognized over the period the underlying account is serviced. Although some trust appointments can last for generations, most contracts are generally cancellable at any time, with the customer subject to a pro-rated fee in the month of termination. Recognition and Measurement of Financial Assets and Financial Liabilities Recognition and Measurement of Financial Assets and Financial Liabilities In addition, the adoption of this ASU resulted in changing how the Company estimates the fair value of portfolio loans for disclosure purposes. Fair values are estimated first by stratifying the portfolios of loans with similar financial characteristics. Loans are segregated by type such as multifamily real estate, residential mortgage, nonresidential mortgage, commercial/agricultural, consumer and other. Each loan category is further segmented into fixed- and adjustable-rate interest terms. An estimate of fair value is then calculated based on discounted cash flows using as a discount rate based on the current rate offered on similar products, plus an adjustment for liquidity to reflect the non-homogeneous nature of the loans, as well as a quarterly loss rate based on historical losses to arrive at an estimated exit price fair value. Fair value for impaired loans is also based on recent appraisals or estimated cash flows discounted using rates commensurate with risk associated with the estimated cash flows. Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information. Derivatives and Hedging (Topic 815) In August 2017, FASB issued ASU No. 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this ASU better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company adopted the provisions of ASU No. 2017-12 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Upon adoption, the Company elected to reclassify $94.8 million of securities held-to-maturity to securities available-for-sale, which did not impact on the Consolidated Statements of Operations Compensation—Stock Compensation (Topic 718) In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting . The amendments in the ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all of the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification. (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified. (3) the classification of the modified award is an equity instrument or liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period, for reporting periods for which financial statements have not yet been issued. The amendments should be applied prospectively to an award modified on or after the adoption date. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-09 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Statement of Cash Flows (Topic 230) In August 2016, FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments . There is diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230 and other Topics. This ASU addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. Those eight issues are (1) debt prepayment or debt extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transactions, and (8) separately identifiable cash flows and application of the predominance principle. Current GAAP either is unclear or does not include specific guidance on these eight cash flow classification issues. These amendments provide guidance for each of the eight issues, thereby reducing current and potential future diversity in practice. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. Given the Company’s emerging growth company status, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company adopted the provisions of ASU No. 2016-15 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash Business Combinations (Topic 805) In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business . The guidance clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. This guidance is effective for annual and interim periods beginning after December 15, 2017. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-01 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Income Statement—Reporting Comprehensive Income (Topic 220) In February 2018, FASB issued ASU No. 2018-02, Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income . The ASU helps organizations address certain stranded income tax effects in accumulated other comprehensive income (AOCI) resulting from the Tax Cuts and Jobs Act. The ASU provides reporting entities with an option to reclassify stranded tax effects within AOCI to retained earnings in each period in which the effect of the change in the U.S. federal corporate income tax rate in the Tax Cuts and Jobs Act (or portion thereof) is recorded. The ASU requires reporting entities to disclose: a description of the accounting policy for releasing income tax effects from AOCI; whether they elect to reclassify the stranded income tax effects from the Tax Cuts and Jobs Act; and information about the other income tax effects that are reclassified. The amendments affect any organization that is required to apply the provisions of Topic 220, Income Statement—Reporting Comprehensive Income , and has items of other comprehensive income for which the related tax effects are presented in other comprehensive income as required by GAAP. The amendments are effective for annual periods beginning after December 15, 2018, and interim periods within those fiscal years. The Company early adopted the new guidance on January 1, 2018. The adoption did not impact the Company’s Statements of Operations, and resulted in a reclassification of $763,000 from accumulated other comprehensive income (loss) to retained earnings. Fair Value Measurement (Topic 820) In August 2018, FASB issued ASU No. 2018-13, Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement . The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820. The amendments remove the disclosure requirements for the amount and reasons for transfers between Level 1 and Level 2 securities of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation processes for Level 3 fair value measurement. The amendments modify the disclosure requirements as follows: in lieu of a rollforward for Level 3 fair value measurements, a nonpublic entity is required to disclose transfers into and out of Level 3 of the fair value hierarchy and purchases and issues of Level 3 assets and liabilities; for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The amendments add the following disclosure requirements: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Early adoption is permitted. The Company early adopted these amendments in 2018, which did not have a material impact on the Company’s Consolidated Financial Statements. Issued Accounting Pronouncements Pending Adoption Leases (Topic 842) In February 2016, FASB issued ASU No. 2016-02, Leases . The amendments in this ASU require lessees to recognize the following for all leases (with the exception of short-term) at the commencement date; a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The amendments in this ASU leave lessor accounting largely unchanged, although certain targeted improvements were made to align lessor accounting with the lessee accounting model. This ASU simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. Lessees will no longer be provided with a source of off-balance sheet financing. The amendments in this ASU are effective for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early application is permitted upon issuance. Lessees (for capital and operating leases) and lessors (for sales-type, direct financing, and operating leases) must apply a modified retrospective transition approach for leases existing at, or entered into after, the beginning of the earliest comparative period presented in the financial statements. The modified retrospective approach would not require any transition accounting for leases that expired before the earliest comparative period presented. Lessees and lessors may not apply a full retrospective transition approach. The Company is evaluating the new guidance and its impact on the Company’s Consolidated Statements of Operations and Consolidated Statements of Financial Condition. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2020. The Company expects an increase in assets and liabilities as a result of recognizing additional right-to-use assets and liabilities under lease contracts in which the Company is lessee. While the Company has not quantified the impact of this ASU on its leasing portfolio, it does not expect a change in its accounting for the initial direct costs of leases. Financial Instruments—Credit Losses (Topic 326) In June 2016, FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments . Current GAAP requires an “incurred loss” methodology for recognizing credit losses that delays recognition until it is probable a loss has been incurred. The main objective of this ASU is to provide financial statement users with more decision-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. The amendments in this ASU replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendments in this ASU require a financial asset (or group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. The measurement of expected credit losses will be based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendments in this ASU broaden the information that an entity must consider in developing its expected credit loss estimate for assets measured either collectively or individually. The use of forecasted information incorporates more timely information in the estimate of expected credit loss, which will be more decision useful to users of the financial statements. The amendments in this ASU will be effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2021. The Company is still evaluating the effects this ASU will have on the Company’s Consolidated Financial Statements. While the Company has not quantified the impact of this ASU, it does expect changing from the current incurred loss model to an expected loss model will result in an earlier recognition of losses. Nonrefundable Fees and Other Costs (Subtopic 310-20) In March 2017, FASB issued ASU No. 2017-08, Receivables—Nonrefundable Fees and Other Costs. The amendments in the ASU shorten the amortization period for certain callable debt securities held at a premium at the earliest call date. Under current GAAP, the Company amortizes the premium as an adjustment of yield over the contractual life of the instrument. As a result, upon exercise of a call on a callable debt security held at a premium, the unamortized premium is charged to earnings. The ASU shortens the amortization period for certain callable debt securities held at a premium and requires the premium to be amortized to the earliest call date. However, the amendments do not require an accounting change for securities held at a discount; the discount continues to be amortized to maturity. The amendments are effective for annual periods beginning after December 15, 2019, and interim periods within annual periods beginning after December 15, 2020. Early adoption is permitted. The Company is required to apply the amendments on a modified retrospective basis through a cumulative-effect adjustment directly to retained earnings as of the beginning of the period of adoption. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2020. The Company is currently evaluating the provisions of ASU No. 2017-08 to determine the potential impact the new standard will have on the Company’s Consolidated Financial Statements.

Accounting Pronouncements Rec_2

Accounting Pronouncements Recently Adopted or Issued (Tables)	3 Months Ended
	Mar. 31, 2019
Accounting Changes And Error Corrections [Abstract]
Impact of Adopting the New Revenue Standard on Consolidated Statements of Operations	The Company adopted ASU 2014-09 using the full retrospective approach. The following table presents the impact of adopting the new revenue standard on our Consolidated Statements of Operations for the periods presented (in thousands): For the Three Months Ended For the Three Months Ended March 31, 2019 March 31, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 717 $ 1,063 $ (346 ) $ 913 $ 1,218 $ (305 ) Non-interest expense: Other non-interest expense $ 2,839 $ 3,185 $ (346 ) $ 1,752 $ 2,057 $ (305 )

Acquisition of a Business (Tabl

Acquisition of a Business (Tables)	3 Months Ended
	Mar. 31, 2019
Business Combinations [Abstract]
Summary of Fair Values of Assets and Liabilities Assumed as of Acquisition Date	The following table presents a summary of the fair values of assets acquired and liabilities assumed as of the acquisition date: Assets Cash and cash equivalents $ 47,378 Securities available-for-sale 128,063 Restricted stock 1,360 Loans 916,011 Premises and equipment 15,890 Other intangible assets 22,276 Deferred tax assets, net 2,302 Other assets 8,845 Total assets acquired 1,142,125 Liabilities Deposits 1,022,268 Junior subordinated debentures 8,497 Accrued expenses and other liabilities 5,844 Total liabilities assumed 1,036,609 Net assets acquired $ 105,516 Consideration paid Common stock (6,682,850 shares issued at $21.62 per share) 144,483 Outstanding stock options converted to Byline stock options 7,644 Cash paid 27,004 Total consideration paid 179,131 Goodwill $ 73,615
Summary of Acquired Non-Impaired Loans as of Acquisition Date	The following table presents the acquired non-impaired loans as of the acquisition date: Fair value $ 890,986 Gross contractual amounts receivable 1,057,374 Estimate of contractual cash flows not expected to be collected (1) 36,544 Estimate of contractual cash flows expected to be collected 1,020,830 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default.
Summary of Pro Forma Information for Results of Operations	The following table provides the unaudited pro forma information for the results of operations for the three months ended March 31, 2018, as if the acquisition had occurred on January 1, 2018. The pro forma results combine the historical results of First Evanston into the Company’s Consolidated Statements of Operations, including the impact of certain acquisition accounting adjustments, which includes loan discount accretion, intangible assets amortization, deposit premium accretion, and borrowing, net of discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2018. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The acquisition-related expenses that have been recognized are included in net income in the following table for the three months ended March 31, 2018. March 31, 2018 Total revenues (net interest income and non-interest income) $ 57,697 Net income $ 10,458 Earnings per share—basic $ 0.29 Earnings per share—diluted $ 0.28

Securities (Tables)

Securities (Tables)	3 Months Ended
	Mar. 31, 2019
Investments Debt And Equity Securities [Abstract]
Summary of Amortized Cost and Fair Values of Securities Available-for-sale, Held to Maturity and Equity and Other Securities	The following March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Equity and other securities, at fair value Mutual funds $ 2,882 $ 2,882 Equity securities 4,334 4,334 Total $ 7,216 $ 7,216 March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 57,323 $ 162 $ (98 ) $ 57,387 U.S. Government agencies 187,458 816 (772 ) 187,502 Obligations of states, municipalities, and political subdivisions 82,049 749 (231 ) 82,567 Residential mortgage-backed securities Agency 347,166 753 (7,435 ) 340,484 Non-agency 132,071 814 (1,219 ) 131,666 Commercial mortgage-backed securities Agency 100,400 78 (2,665 ) 97,813 Non-agency 31,380 — (545 ) 30,835 Corporate securities 36,666 59 (426 ) 36,299 Other securities — — — — Total $ 974,513 $ 3,431 $ (13,391 ) $ 964,553 March 31, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 4,425 $ 22 $ (16 ) $ 4,431 Total $ 4,425 $ 22 $ (16 ) $ 4,431 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 52,775 $ 81 $ (189 ) $ 52,667 U.S. Government agencies 187,427 367 (1,296 ) 186,498 Obligations of states, municipalities, and political subdivisions 60,686 133 (586 ) 60,233 Residential mortgage-backed securities Agency 284,038 101 (11,176 ) 272,963 Non-agency 84,998 199 (1,576 ) 83,621 Commercial mortgage-backed securities Agency 93,543 55 (3,164 ) 90,434 Non-agency 31,458 — (1,000 ) 30,458 Corporate securities 34,716 67 (610 ) 34,173 Other securities 4,613 2,127 (131 ) 6,609 Total $ 834,254 $ 3,130 $ (19,728 ) $ 817,656 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,835 $ 40 $ (210 ) $ 23,665 Residential mortgage-backed securities Agency 40,082 93 (531 ) 39,644 Non-agency 35,349 — (919 ) 34,430 Total $ 99,266 $ 133 $ (1,660 ) $ 97,739
Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Available-for-sale and Held to Maturity	Gross unrealized losses and fair values, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of March 31, 2019 and December 31, 2018, are summarized as follows: Less than 12 Months 12 Months or Longer Total March 31, 2019 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 13 $ 7,965 $ (2 ) $ 14,891 $ (96 ) $ 22,856 $ (98 ) U.S. Government agencies 20 38,421 (50 ) 50,613 (722 ) 89,034 (772 ) Obligations of states, municipalities and political subdivisions 30 542 (1 ) 20,376 (230 ) 20,918 (231 ) Residential mortgage-backed securities Agency 57 — — 276,827 (7,435 ) 276,827 (7,435 ) Non-agency 13 — — 82,304 (1,219 ) 82,304 (1,219 ) Commercial mortgage-backed securities Agency 11 25,364 (128 ) 65,029 (2,537 ) 90,393 (2,665 ) Non-agency 5 — — 30,835 (545 ) 30,835 (545 ) Corporate securities 12 15,756 (229 ) 8,250 (197 ) 24,006 (426 ) Other securities — — — — — — — Total 161 $ 88,048 $ (410 ) $ 549,125 $ (12,981 ) $ 637,173 $ (13,391 ) Less than 12 Months 12 Months or Longer Total March 31, 2019 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 4 $ — $ — $ 2,605 $ (16 ) $ 2,605 $ (16 ) Total 4 $ — $ — $ 2,605 $ (16 ) $ 2,605 $ (16 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 18 $ 23,835 $ (52 ) $ 9,865 $ (137 ) $ 33,700 $ (189 ) U.S. Government agencies 25 43,487 (80 ) 50,101 (1,216 ) 93,588 (1,296 ) Obligations of states, municipalities and political subdivisions 56 13,926 (97 ) 18,563 (489 ) 32,489 (586 ) Residential mortgage-backed securities Agency 42 4,288 (45 ) 254,121 (11,131 ) 258,409 (11,176 ) Non-agency 8 59,107 (1,378 ) 4,009 (198 ) 63,116 (1,576 ) Commercial mortgage-backed securities Agency 9 21,356 (447 ) 52,640 (2,717 ) 73,996 (3,164 ) Non-agency 5 — — 30,458 (1,000 ) 30,458 (1,000 ) Corporate securities 15 25,762 (342 ) 4,642 (268 ) 30,404 (610 ) Other securities 1 — — 2,844 (131 ) 2,844 (131 ) Total 179 $ 191,761 $ (2,441 ) $ 427,243 $ (17,287 ) $ 619,004 $ (19,728 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 23 $ 8,127 $ (58 ) $ 8,792 $ (152 ) $ 16,919 $ (210 ) Residential mortgage-backed securities Agency 16 6,625 (150 ) 21,139 (381 ) 27,764 (531 ) Non-agency 7 21,499 (503 ) 12,931 (416 ) 34,430 (919 ) Total 46 $ 36,251 $ (711 ) $ 42,862 $ (949 ) $ 79,113 $ (1,660 )
Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity	At March 31, 2019, the Amortized Cost Fair Value Available-for-sale Due in one year or less $ 83,952 $ 83,767 Due from one to five years 161,739 161,679 Due from five to ten years 91,146 91,405 Due after ten years 26,659 26,904 Mortgage-backed securities 611,017 600,798 Total $ 974,513 $ 964,553 Held-to-maturity Due from one to five years $ 3,262 $ 3,264 Due from five to ten years 1,163 1,167 Total $ 4,425 $ 4,431 Equity and other securities, at fair value Due after ten years $ 695 $ 695 No defined maturity 6,521 6,521 Total $ 7,216 $ 7,216

Loan and Lease Receivables (Tab

Loan and Lease Receivables (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Schedule of Outstanding Loan and Lease Receivables	Outstanding loan and lease receivables as of the dates shown were categorized as follows: March 31, December 31, 2019 2018 Commercial real estate $ 1,262,236 $ 1,261,594 Residential real estate 699,088 704,899 Construction, land development, and other land 214,562 186,258 Commercial and industrial 1,189,710 1,145,240 Installment and other 12,766 13,675 Lease financing receivables 186,743 187,797 Total loans and leases 3,565,105 3,499,463 Net unamortized deferred fees and costs (764 ) (1,293 ) Initial direct costs 3,225 3,456 Allowance for loan and lease losses (27,106 ) (25,201 ) Net loans and leases $ 3,540,460 $ 3,476,425 March 31, December 31, 2019 2018 Lease financing receivables Net minimum lease payments $ 203,238 $ 204,646 Unguaranteed residual values 1,511 1,535 Unearned income (18,006 ) (18,384 ) Total lease financing receivables 186,743 187,797 Initial direct costs 3,225 3,456 Lease financial receivables before allowance for lease losses $ 189,968 $ 191,253
Summary of Minimum Annual Lease Payments for Lease Financing Receivables	The minimum Minimum Lease Payments 2019 $ 56,181 2020 62,573 2021 43,337 2022 27,072 2023 12,269 Thereafter 1,806 Total $ 203,238
Summary of Balances for Each Respective Loan and Lease Category	The following March 31, 2019 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 738,832 $ 141,199 $ 382,252 $ 1,262,283 Residential real estate 494,877 106,764 97,395 699,036 Construction, land development, and other land 181,427 3,111 29,121 213,659 Commercial and industrial 900,709 11,963 277,146 1,189,818 Installment and other 11,082 374 1,346 12,802 Lease financing receivables 160,607 — 29,361 189,968 Total loans and leases $ 2,487,534 $ 263,411 $ 816,621 $ 3,567,566 December 31, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 652,234 $ 146,808 $ 462,565 $ 1,261,607 Residential real estate 466,309 113,934 124,659 704,902 Construction, land development, and other land 144,128 3,779 37,442 185,349 Commercial and industrial 803,508 12,617 328,672 1,144,797 Installment and other 11,718 404 1,596 13,718 Lease financing receivables 159,901 — 31,352 191,253 Total loans and leases $ 2,237,798 $ 277,542 $ 986,286 $ 3,501,626
Schedule of Estimated Fair Value of Impaired Loans Acquired at Acquisition	The following table presents a reconciliation of the undiscounted contractual cash flows, non-accretable difference, accretable yield, and fair value of acquired impaired loans as of the acquisition date of May 31, 2018: Undiscounted contractual cash flows $ 33,594 Undiscounted cash flows not expected to be collected (non-accretable difference) (5,003 ) Undiscounted cash flows expected to be collected 28,591 Accretable yield at acquisition (3,566 ) Estimated fair value of impaired loans acquired at acquisition $ 25,025
Summary of Outstanding Balance and Carrying Amount of All Acquired Impaired Loans	The outstanding March 31, 2019 December 31, 2018 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 194,328 $ 141,199 $ 216,137 $ 146,808 Residential real estate 155,075 106,764 173,962 113,934 Construction, land development, and other land 10,849 3,111 11,962 3,779 Commercial and industrial 16,794 11,963 24,972 12,617 Installment and other 1,205 374 1,735 404 Total acquired impaired loans $ 378,251 $ 263,411 $ 428,768 $ 277,542
Summary of Changes in Accretable Yield for Acquired Impaired Loans	The following table summarizes the changes in accretable yield for acquired impaired loans for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Beginning balance $ 37,115 $ 36,446 Additions — — Accretion to interest income (5,250 ) (5,691 ) Reclassification from (to) nonaccretable difference, net (2,525 ) 8,545 Ending balance $ 29,340 $ 39,300
Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-Impaired Loans and Leases	The unpaid March 31, 2019 December 31, 2018 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 391,806 $ 382,252 $ 473,262 $ 462,565 Residential real estate 99,828 97,395 127,478 124,659 Construction, land development, and other land 30,081 29,121 38,494 37,442 Commercial and industrial 284,997 277,146 344,879 328,672 Installment and other 1,375 1,346 1,831 1,596 Lease financing receivables 30,852 29,361 32,977 31,352 Total acquired non-impaired loans and leases $ 838,939 $ 816,621 $ 1,018,921 $ 986,286

Allowance for Loan and Lease _2

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments (Tables)	3 Months Ended
	Mar. 31, 2019
Receivables [Abstract]
Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances	The following March 31, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Allowance for loan and lease losses Three months ended Beginning balance $ 7,540 $ 1,751 $ 466 $ 12,932 $ 49 $ 2,463 $ 25,201 Provisions 442 218 70 3,032 14 223 3,999 Charge-offs (1,351 ) — — (352 ) — (645 ) (2,348 ) Recoveries 29 1 — 18 — 206 254 Ending balance $ 6,660 $ 1,970 $ 536 $ 15,630 $ 63 $ 2,247 $ 27,106 Ending balance: Individually evaluated for impairment $ 1,403 $ 34 $ — $ 6,122 $ — $ — $ 7,559 Collectively evaluated for impairment 4,141 1,516 536 8,200 61 2,247 16,701 Loans acquired with deteriorated credit quality 1,116 420 — 1,308 2 — 2,846 Total allowance for loan and lease losses $ 6,660 $ 1,970 $ 536 $ 15,630 $ 63 $ 2,247 $ 27,106 March 31, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Loans and leases ending balance: Individually evaluated for impairment $ 17,354 $ 2,060 $ — $ 24,384 $ — $ — $ 43,798 Collectively evaluated for impairment 1,103,730 590,212 210,548 1,153,471 12,428 189,968 3,260,357 Loans acquired with deteriorated credit quality 141,199 106,764 3,111 11,963 374 — 263,411 Total loans and leases $ 1,262,283 $ 699,036 $ 213,659 $ 1,189,818 $ 12,802 $ 189,968 $ 3,567,566 March 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Allowance for loan and lease losses Three months ended Beginning balance $ 4,794 $ 1,638 $ 222 $ 7,418 $ 41 $ 2,593 $ 16,706 Provisions (releases) 934 (74 ) 397 3,424 20 414 5,115 Charge-offs (409 ) — (418 ) (3,085 ) — (510 ) (4,422 ) Recoveries — — — 6 — 235 241 Ending balance $ 5,319 $ 1,564 $ 201 $ 7,763 $ 61 $ 2,732 $ 17,640 Ending balance: Individually evaluated for impairment $ 1,572 $ 153 $ — $ 2,963 $ 14 $ — $ 4,702 Collectively evaluated for impairment 1,827 1,036 177 3,626 11 2,732 9,409 Loans acquired with deteriorated credit quality 1,920 375 24 1,174 36 — 3,529 Total allowance for loan and lease losses $ 5,319 $ 1,564 $ 201 $ 7,763 $ 61 $ 2,732 $ 17,640 March 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Loans and leases ending balance: Individually evaluated for impairment $ 12,375 $ 2,029 $ — $ 12,598 $ 14 $ — $ 27,016 Collectively evaluated for impairment 670,538 426,272 111,914 548,076 3,667 181,461 1,941,928 Loans acquired with deteriorated credit quality 157,956 139,858 5,156 8,055 449 — 311,474 Total loans and leases $ 840,869 $ 568,159 $ 117,070 $ 568,729 $ 4,130 $ 181,461 $ 2,280,418
Summary of Recorded Investment, Unpaid Principal Balance, and Related Allowance for Loans and Leases Considered Impaired	The following and March 31, 2019 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 11,643 $ 13,669 $ — Residential real estate 1,838 1,841 — Commercial and industrial 10,907 12,785 — With an allowance recorded Commercial real estate 5,711 5,959 1,403 Residential real estate 222 222 34 Commercial and industrial 13,477 14,111 6,122 Total impaired loans $ 43,798 $ 48,587 $ 7,559 December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 6,110 $ 7,693 $ — Residential real estate 1,886 1,858 — Commercial and industrial 11,193 13,961 — With an allowance recorded Commercial real estate 5,873 6,313 2,191 Residential real estate 251 253 61 Commercial and industrial 10,601 11,153 4,397 Total impaired loans $ 35,914 $ 41,231 $ 6,649
Summary of Average Recorded Investment and Interest Income Recognized for Loans and Leases Considered Impaired	The following tables summarize the average recorded investment and interest income recognized for loans and leases considered impaired, which excludes acquired impaired loans, for the three months ended as follows: March 31, 2019 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 7,345 $ 119 Residential real estate 1,541 13 Commercial and industrial 11,381 126 With an allowance recorded Commercial real estate 5,186 48 Residential real estate 226 2 Commercial and industrial 11,377 154 Total impaired loans $ 37,056 $ 462 March 31, 2018 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 9,039 $ 103 Residential real estate 1,930 10 Commercial and industrial 7,300 62 With an allowance recorded Commercial real estate 4,122 37 Residential real estate 351 1 Commercial and industrial 6,975 102 Installment and other 14 — Total impaired loans $ 29,731 $ 315
Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation	The following March 31, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 996,417 $ 554,892 $ 172,720 $ 989,123 $ 12,404 $ 186,230 $ 2,911,786 Watch 87,343 29,753 37,828 129,730 17 42 284,713 Special Mention 19,904 5,410 — 33,489 — 2,512 61,315 Substandard 17,420 2,217 — 25,513 7 328 45,485 Doubtful — — — — — 856 856 Loss — — — — — — — Total $ 1,121,084 $ 592,272 $ 210,548 $ 1,177,855 $ 12,428 $ 189,968 $ 3,304,155 December 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 1,009,041 $ 553,665 $ 147,123 $ 962,291 $ 9,997 $ 188,314 $ 2,870,431 Watch 76,276 29,522 31,376 112,996 3,302 80 253,552 Special Mention 17,602 5,656 3,071 34,314 — 1,794 62,437 Substandard 11,880 2,125 — 22,579 15 818 37,417 Doubtful — — — — — 247 247 Loss — — — — — — — Total $ 1,114,799 $ 590,968 $ 181,570 $ 1,132,180 $ 13,314 $ 191,253 $ 3,224,084
Summary of Contractual Delinquency Information	The following tables summarize contractual delinquency information for acquired non-impaired and originated loans and leases by category at March 31, 2019 and December 31, 2018: March 31, 2019 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 17,155 $ 1,944 $ — $ 9,677 $ 28,776 $ 1,092,308 $ 1,121,084 Residential real estate 1,337 1,248 — 2,070 4,655 587,617 592,272 Construction, land development, and other land 12,009 — — — 12,009 198,539 210,548 Commercial and industrial 11,454 117 — 15,931 27,502 1,150,353 1,177,855 Installment and other 12 6 — 5 23 12,405 12,428 Lease financing receivables 1,093 328 — 856 2,277 187,691 189,968 Total $ 43,060 $ 3,643 $ — $ 28,539 $ 75,242 $ 3,228,913 $ 3,304,155 December 31, 2018 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 6,659 $ 2,145 $ — $ 9,484 $ 18,288 $ 1,096,511 $ 1,114,799 Residential real estate 4,488 711 — 1,815 7,014 583,954 590,968 Construction, land development, and other land — — — — — 181,570 181,570 Commercial and industrial 5,829 1,376 — 13,932 21,137 1,111,043 1,132,180 Installment and other 1,932 4 — 12 1,948 11,366 13,314 Lease financing receivables 789 530 — 591 1,910 189,343 191,253 Total $ 19,697 $ 4,766 $ — $ 25,834 $ 50,297 $ 3,173,787 $ 3,224,084
Summary of TDR's by Loan Category	The tables below present TDRs by loan category as of March 31, 2019 and December 31, 2018: March 31, 2019 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 4 $ 1,486 $ 1,486 $ — $ 124 Commercial and industrial 2 216 216 — 99 Residential real estate 2 219 219 — — Total accruing 8 1,921 1,921 — 223 Non-accruing: Commercial real estate 9 2,690 2,119 571 141 Commercial and industrial 8 6,871 5,000 1,871 1,271 Total non-accruing 17 9,561 7,119 2,442 1,412 Total troubled debt restructurings 25 $ 11,482 $ 9,040 $ 2,442 $ 1,635 December 31, 2018 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 4 $ 1,508 $ 1,508 $ — $ 113 Commercial and industrial 2 191 191 — 100 Residential real estate 1 114 114 — — Total accruing 7 1,813 1,813 — 213 Non-accruing: Commercial real estate 9 2,512 2,471 41 743 Commercial and industrial 6 6,714 4,843 1,871 1,290 Total non-accruing 15 9,226 7,314 1,912 2,033 Total troubled debt restructurings 22 $ 11,039 $ 9,127 $ 1,912 $ 2,246
Summary of Loans Modified as Troubled Debt Restructurings	Loans modified three months ended March 31, 2019 For the Three Months Ended March 31, 2019 2018 Accruing: Beginning balance $ 1,813 $ 1,061 Additions 113 — Net payments (5 ) (24 ) Net transfers from non-accrual — — Ending balance 1,921 1,037 Non-accruing: Beginning balance 7,314 1,569 Additions 246 — Net payments 89 (332 ) Charge-offs (530 ) (144 ) Net transfers from accrual — — Ending balance 7,119 1,093 Total troubled debt restructurings 9,040 2,130

Servicing Assets (Tables)

Servicing Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Transfers And Servicing [Abstract]
Activity for Servicing Assets and Related Changes in Fair Value	Activity for the three months ended March 31, 2019 and 2018 is Three Months Ended March 31, 2019 2018 Beginning balance $ 19,693 $ 21,400 Additions, net 1,102 2,102 Changes in fair value (1,261 ) (1,887 ) Ending balance $ 19,534 $ 21,615
Unpaid Principal Balances of Loans Serviced for Others	The unpaid as of and were as follows: March 31, December 31, 2019 2018 Loan portfolios serviced for: SBA guaranteed loans $ 1,160,938 $ 1,151,915 USDA guaranteed loans 103,503 106,184 Total $ 1,264,441 $ 1,258,099

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	3 Months Ended
	Mar. 31, 2019
Banking And Thrift [Abstract]
Change in Other Real Estate Owned	The following table presents the change in other real estate owned (“OREO”) for the three months ended March 31, 2019 and 2018 Three Months Ended March 31, 2019 2018 Beginning balance $ 5,314 $ 10,626 Net additions to OREO 230 1,044 Proceeds from sales of OREO (628 ) (1,263 ) Gains (losses) on sales of OREO (33 ) 140 Valuation adjustments (84 ) (81 ) Ending balance $ 4,799 $ 10,466

Goodwill, Core Deposit Intang_2

Goodwill, Core Deposit Intangible and Other Intangible Assets (Tables)	3 Months Ended
	Mar. 31, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets	The following tables summarize the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the three months ended March 31, 2019 and 2018 Three Months Ended March 31, 2019 2018 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 128,177 $ 30,360 $ 3,059 $ 54,562 $ 16,720 $ — Amortization — (1,706 ) (67 ) — (761 ) — Ending balance $ 128,177 $ 28,654 $ 2,992 $ 54,562 $ 15,959 $ — Accumulated amortization N/A $ 20,592 $ 224 N/A $ 14,227 N/A Weighted average remaining amortization period N/A 6.6 Years 11.2 Years N/A 5.4 Years N/A
Estimated Amortization Expense for Core Deposit Intangible, Customer Relationship Intangible and Other Intangible Assets Recognized	The following table presents the estimated amortization expense for core deposit intangible, customer relationship intangible, and other intangible assets recognized at March 31, 2019: Estimated Amortization 2019 $ 5,153 2020 6,476 2021 6,025 2022 5,578 2023 3,645 Thereafter 4,769 Total $ 31,646

Deposits (Tables)

Deposits (Tables)	3 Months Ended
	Mar. 31, 2019
Deposits [Abstract]
Composition of Deposits	The composition of deposits was as follows as of March 31, 2019 and December 31, 2018: March 31, December 31, 2019 2018 Non-interest-bearing demand deposits $ 1,163,255 $ 1,192,873 Interest-bearing checking accounts 305,393 296,339 Money market demand accounts 611,634 640,401 Other savings 468,524 476,418 Time deposits (below $250,000) 967,999 911,603 Time deposits ($250,000 and above) 291,711 232,282 Total deposits $ 3,808,516 $ 3,749,916

Federal Home Loan Bank Advanc_2

Federal Home Loan Bank Advances (Tables)	3 Months Ended
	Mar. 31, 2019
Federal Home Loan Banks [Abstract]
Summary of FHLB Advances	The following March 31, December 31, 2019 2018 Federal Home Loan Bank advances $ 425,000 $ 425,000 Weighted average cost 2.59 % 2.56 %

Other Borrowings (Tables)

Other Borrowings (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Summary of Other Borrowings	The following is a summary of the Company’s other borrowings as of March 31, 2019 and December 31, 2018: March 31, December 31, 2019 2018 Securities sold under agreements to repurchase $ 34,369 $ 34,166 Line of credit — — Total $ 34,369 $ 34,166
Summary of Short-term Credit Lines Available for Use	The following March 31, December 31, 2019 2018 Federal Reserve Bank of Chicago discount window line $ 314,229 $ 293,613 Available federal funds lines 85,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures (Tables)	3 Months Ended
	Mar. 31, 2019
Debt Disclosure [Abstract]
Junior Subordinated Debentures by Issuance	At March 31, 2019 and December 31, 2018, the Name of Trust Aggregate Principal Amount March 31, 2019 Aggregate Principal Amount December 31, 2018 Stated Maturity Contractual Rate at March 31, 2019 Interest Rate Spread Metropolitan $ 35,000 $ 35,000 March 5.40 % Three-month LIBOR + 2.79% RidgeStone Capital Trust I 1,500 1,500 June 30, 2033 6.38 % Five-year LIBOR + 3.50% First Evanston Bancorp Trust I 10,000 10,000 March 15, 2035 4.39 % Three-month LIBOR + 1.78% Total liability, at par 46,500 46,500 Discount (9,588 ) (9,732 ) Total liability, at carrying value $ 36,912 $ 36,768

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	3 Months Ended
	Mar. 31, 2019
Commitments And Contingencies Disclosure [Abstract]
Summary of Minimum Annual Rental Commitments for Operating Leases	The minimum Minimum Commitments 2019 $ 2,714 2020 3,221 2021 2,961 2022 1,954 2023 1,012 Thereafter 3,069 Total $ 14,931
Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments	The following March 31, December 31, 2019 2018 Fixed Rate Variable Rate Fixed Rate Variable Rate Commitments to extend credit $ 80,916 $ 875,341 $ 74,099 $ 928,991 Letters of credit 1,750 34,154 1,982 34,071 Total $ 82,666 $ 909,495 $ 76,081 $ 963,062

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	3 Months Ended
	Mar. 31, 2019
Fair Value Disclosures [Abstract]
Summary of Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following Fair Value Measurements Using March 31, 2019 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 57,387 $ 57,387 $ — $ — U.S. Government agencies 187,502 — 187,502 — Obligations of states, municipalities, and political subdivisions 82,567 — 82,372 195 Mortgage-backed securities; residential Agency 340,484 — 340,484 — Non-Agency 131,666 — 131,666 — Mortgage-backed securities; commercial Agency 97,813 — 97,813 — Non-Agency 30,835 — 30,835 — Corporate securities 36,299 — 36,299 — Equity and other securities, at fair value Mutual funds 2,882 2,882 — — Equity securities 4,334 — 3,639 695 Servicing assets 19,534 — — 19,534 Derivative assets 9,788 — 9,788 — Financial liabilities Derivative liabilities 5,984 — 5,984 — Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 52,667 $ 52,667 $ — $ — U.S. Government agencies 186,498 — 186,498 — Obligations of states, municipalities, and political subdivisions 60,233 — 60,038 195 Mortgage-backed securities; residential Agency 272,963 — 272,963 — Non-Agency 83,621 — 83,621 — Mortgage-backed securities; commercial Agency 90,434 — 90,434 — Non-Agency 30,458 — 30,458 — Corporate securities 34,173 — 34,173 — Other securities 6,609 2,844 3,074 691 Servicing assets 19,693 — — 19,693 Derivative assets 10,740 — 10,740 — Financial liabilities Derivative liabilities 4,243 — 4,243 —
Summary of Financial Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs	The following table presents additional information about financial assets measured at fair value on recurring basis for which the Company used significant unobservable inputs (Level 3): Three Months Ended March 31, 2019 2018 2019 2018 Investment Securities Servicing Assets Balance, beginning of period $ 886 $ 1,052 $ 19,693 $ 21,400 Additions, net — — 1,102 2,102 Amortization 1 1 — — Change in unrealized gain — 14 — — Change in fair value 3 — (1,261 ) (1,887 ) Balance, end of period $ 890 $ 1,067 $ 19,534 $ 21,615
Summary of Unobservable Inputs Used in the Fair Value Measurements on Recurring Basis	The following Financial Instruments Valuation Technique Unobservable Inputs Range of Inputs Weighted Average Range Impact to Valuation from an Increased or Higher Input Value Obligations of states, municipalities, and political obligations Discounted Probability of default 2.4% 2.4% Decrease Single issuer trust preferred Discounted cash flow Probability of default 4.9%—5.4% 5.9% Decrease Servicing assets Discounted cash flow Prepayment speeds 2.1%—17.7% 11.9% Decrease Discount rate 7.1%—21.8% 14.3% Decrease Expected weighted average loan life 0.1—10.5 years 5.0 years Increase
Summary of Company's Assets Measured at Fair Value on a Non-Recurring Basis	The following tables Fair Value Measurements Using March 31, 2019 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 15,951 $ — $ — $ 15,951 Residential real estate 2,026 — — 2,026 Construction, land development, and other land — — — — Commercial and industrial 18,262 — — 18,262 Assets held for sale 13,596 — — 13,596 Other real estate owned 4,799 — — 4,799 Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 9,792 $ — $ — $ 9,792 Residential real estate 2,076 — — 2,076 Construction, land development, and other land — — — — Commercial and industrial 17,397 — — 17,397 Installment and other — — — — Assets held for sale 14,489 — — 14,489 Other real estate owned 5,314 — — 5,314
Estimated Fair Values of Financial Instruments	The estimated March 31, December 31, Fair Value 2019 2018 Hierarchy Level Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets Cash and due from banks 1 $ 50,026 $ 50,026 $ 30,190 $ 30,190 Interest bearing deposits with other banks 2 31,971 31,971 91,670 91,670 Securities held-to-maturity 2 4,425 4,431 99,266 97,739 Other restricted stock 2 19,202 19,202 19,202 19,202 Loans held for sale 3 510 563 19,827 21,654 Loans and lease receivables, net (less impaired loans at fair value (1) 3 3,496,662 3,401,501 3,447,160 3,407,652 Accrued interest receivable 3 11,974 11,974 10,863 10,863 Financial liabilities Non-interest-bearing deposits 2 1,163,255 1,163,255 1,192,873 1,192,873 Interest-bearing deposits 2 2,645,261 1,268,458 2,557,043 2,554,329 Accrued interest payable 2 4,390 4,390 3,484 3,484 Line of credit 2 — — — — Federal Home Loan Bank advances 2 425,000 425,000 425,000 425,000 Securities sold under repurchase agreement 2 34,369 34,369 34,166 34,166 Junior subordinated debentures 3 36,912 42,292 36,768 42,351 (1) In accordance with the prospective adoption of ASU 2016-01, the fair value of loans and lease receivables, net (less impaired loans at fair value) as of March 31, 2019 was measured using an exit price notion. The fair value as of December 31, 2018 was measured using an entry price notion.

Derivative Instruments and He_2

Derivative Instruments and Hedge Activities (Tables)	3 Months Ended
	Mar. 31, 2019
Summary of Derivative Financial Instruments and Classification on Consolidated Statements of Financial Condition	The following tables present the fair value of the Company’s derivative financial instruments and classification on the Consolidated Statements of Financial Condition as of March 31, 2019 and December 31, 2018: March 31, 2019 December 31, 2018 Fair Value Fair Value Notional Amount Other Assets Other Liabilities Notional Amount Other Assets Other Liabilities Derivatives designated as hedging instruments Interest rate swaps designated as cash flow hedges $ 250,000 $ 4,160 $ — $ 250,000 $ 6,699 $ — Derivatives not designated as hedging instruments Other interest rate derivatives 324,793 5,628 5,976 294,545 4,041 4,237 Other credit derivatives 4,504 — 8 4,424 — 6 Total derivatives $ 579,297 $ 9,788 $ 5,984 $ 548,969 $ 10,740 $ 4,243
Summary of Net Gains (Losses) Recorded in Accumulated Other Comprehensive Income (Loss) and Consolidated Statements of Operations Relating to Cash Flow Derivative Instruments	The following table reflects the net gains (losses) recorded in accumulated other comprehensive income (loss) and the Consolidated Statements of Operations relating to the cash flow derivative instruments for the three months ended: March 31, 2019 March 31, 2018 Amount of Gain Recognized in OCI Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Amount of Gain Recognized in OCI Amount of Gain Reclassified from OCI to Income as an Increase to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Interest rate swaps $ (1,817 ) $ 705 $ — $ 4,070 $ 61 $ —
Summary of Other Interest Rate Derivatives	The following table reflects other interest rate derivatives as of March 31, 2019 Notional amounts $ 324,793 Derivative assets fair value 5,628 Derivative liabilities fair value 5,976 Weighted average pay rates 4.82 % Weighted average receive rates 4.64 % Weighted average maturity 5.9 years
Summary of Company's Interest Rate Derivative and Offsetting Positions	T he Company records interest rate derivatives subject to master netting agreements at their gross value and does not offset derivative asset and liabilities on the Consolidated Statements of Financial Condition. The table below summarizes the Company’s interest rate derivatives and offsetting positions as of: March 31, 2019 December 31, 2018 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 9,788 $ 5,984 $ 10,740 $ 4,243 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 9,788 $ 5,984 $ 10,740 $ 4,243 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (3,852 ) (3,852 ) (2,823 ) (2,823 ) Collateral posted (5,433 ) (2,265 ) (7,917 ) (1,317 ) Net credit exposure $ 503 $ (133 ) $ — $ 103
Cash Flow Hedges
Summary of Cash Flow Hedges	The following table reflects the cash flow hedges as of March 31, 2019: Notional amounts $ 250,000 Derivative assets fair value 4,160 Derivative liabilities fair value — Weighted average pay rates 1.67 % Weighted average receive rates 2.82 % Weighted average maturity 2.9 years

Share-Based Compensation (Table

Share-Based Compensation (Tables)	3 Months Ended
	Mar. 31, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Stock Compensation Expense	The following table summarizes stock option compensation expense for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Total share-based compensation - stock options $ 33 $ 229 Income tax benefit 9 64 Unrecognized compensation expense - stock options 113 499 Weighted-average amortization period remaining 0.8 years 1.1 years
Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Stock Compensation Expense	The following table summarizes restricted stock compensation expense for the three months ended March 31, 2019 and 2018: Three Months Ended March 31, 2019 2018 Total share-based compensation - restricted stock $ 353 $ 112 Income tax benefit 98 31 Unrecognized compensation expense 2,675 1,114 Weighted-average amortization period remaining 2.7 years 2.6 years
Omnibus Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Changes in Restricted Shares	The following table discloses the changes in restricted shares for the three months ended March 31, 2019: Omnibus Plan Number of Shares Weighted Average Grant Date Fair Value Beginning balance, January 1, 2019 196,480 $ 21.66 Granted — — Vested (6,134 ) 20.69 Forfeited (8,500 ) 21.03 Ending balance outstanding at March 31, 2019 181,846 $ 21.72
BYB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Fair Value Assumptions of Stock Options	The fair values of the stock options were determined using the Black-Scholes-Merton model for Time Options and a Monte Carlo simulation model for Performance Options.
Summary of Activity in shares Subjected to Options and Weighted Average Exercise Prices	The following table discloses the activity in shares subject to options and the weighted average exercise prices, in actual dollars, for the three months ended March 31, 2019: BYB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 1,598,872 $ 11.84 $ 7,713 6.6 Exercised (10,000 ) 16.25 $ 32 Forfeited — Ending balance outstanding at March 31, 2019 1,588,872 $ 11.81 $ 10,601 6.3 Exercisable at March 31, 2019 1,490,572 $ 11.52 $ 10,382 6.3
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Activity in shares Subjected to Options and Weighted Average Exercise Prices	The following table discloses the activity in shares subject to options under the FEB Plan and the weighted average exercise prices, in actual dollars, for the three months ended March 31, 2019: FEB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 624,383 $ 11.31 $ 3,339 5.2 Granted — Expired — Exercised (40,662 ) 11.63 $ 316 Forfeited — Ending balance outstanding at March 31, 2019 583,721 $ 11.29 $ 4,197 4.9 Exercisable at March 31, 2019 583,721 $ 11.29 $ 4,197 4.9

Earnings per Share (Tables)

Earnings per Share (Tables)	3 Months Ended
	Mar. 31, 2019
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Earnings per Share	The following represent the calculation of basic and diluted earnings per share for the periods presented: Three Months Ended March 31, 2019 2018 Net income $ 12,597 $ 6,768 Less: Dividends on preferred shares 196 193 Net income available to common stockholders $ 12,401 $ 6,575 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 36,169,477 29,291,179 Incremental shares 707,097 622,454 Weighted-average common stock outstanding (dilutive) 36,876,574 29,913,633 Basic earnings per common share $ 0.34 $ 0.22 Diluted earnings per common share $ 0.34 $ 0.22

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	3 Months Ended
	Mar. 31, 2019
Equity [Abstract]
Summary of Preferred and Common Stock	A summary of the Company’s preferred and common stock at March 31, 2019 and December 31, 2018 is as follows: March 31, December 31, 2019 2018 Series B 7.5% fixed to floating non-cumulative perpetual preferred stock Par value $ 0.01 $ 0.01 Shares authorized 50,000 50,000 Shares issued 10,438 10,438 Shares outstanding 10,438 10,438 Common stock, voting Par value $ 0.01 $ 0.01 Shares authorized 150,000,000 150,000,000 Shares issued 36,398,144 36,343,239 Shares outstanding 36,398,144 36,343,239

Consolidated Statements of Ch_3

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Tables)	3 Months Ended
	Mar. 31, 2019
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Schedule of Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in accumulated other comprehensive income (loss) for the three months ended March 31, 2019 and 2018: (dollars in thousands) Unrealized Gains (Losses) on Cash Flow Hedges Unrealized (Losses) on Available-for -Sale Securities Total Accumulated Other Comprehensive Income (Loss) Balance, January 1, 2018 $ 2,913 $ (8,000 ) $ (5,087 ) Reclassification of certain income tax effects from accumulated other comprehensive income 687 (1,450 ) (763 ) Other comprehensive income (loss), net of tax 2,893 (6,457 ) (3,564 ) Balance, March 31, 2018 $ 6,493 $ (15,907 ) $ (9,414 ) Balance, January 1, 2019 $ 4,763 $ (14,261 ) $ (9,498 ) Adoption of ASU 2016-01 — (1,440 ) (1,440 ) Other comprehensive income (loss), net of tax (1,820 ) 6,339 4,519 Balance, March 31, 2019 $ 2,943 $ (9,362 ) $ (6,419 )

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details)	Apr. 30, 2019USD ($)shares	Apr. 30, 2018USD ($)	Mar. 31, 2019segment
Basis Of Presentation [Line Items]
Number of reportable segments | segment			1
Oak Park River Forest
Basis Of Presentation [Line Items]
Consideration paid in cash		$ 4,200,000
Oak Park River Forest | Subsequent Event
Basis Of Presentation [Line Items]
Right to receive common stock upon conversion | shares	7.9321
Consideration paid in cash	$ 33,375
Total merger consideration	$ 39,600,000

Accounting Pronouncements Rec_3

Accounting Pronouncements Recently Adopted or Issued - Additional Information (Details) - USD ($)	Jan. 01, 2019	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in ATM and interchange fees		$ (1,440,000)
Equity and other securities, at fair value		7,216,000
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)			$ (763,000)
ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in ATM and interchange fees		346,000	$ 305,000
ASU 2016-01
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification from other comprehensive income to retained earnings	$ 1,400,000
Equity and other securities, at fair value				$ 6,600,000
ASU 2017-12
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of securities held-to-maturity to securities available-for-sale	$ 94,800,000
ASU 2018-02
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)		$ 763,000

Accounting Pronouncements Rec_4

Accounting Pronouncements Recently Adopted or Issued - Impact of Adopting the New Revenue Standard on Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Non-interest income:
ATM and interchange fees	$ 717	$ 913
Non-interest expense:
Other non-interest expense	2,839	1,752
Balance without Adoption of ASC 606 | ASU 2014-09
Non-interest income:
ATM and interchange fees	1,063	1,218
Non-interest expense:
Other non-interest expense	3,185	2,057
Effect of Change | ASU 2014-09
Non-interest income:
ATM and interchange fees	(346)	(305)
Non-interest expense:
Other non-interest expense	$ (346)	$ (305)

Acquisition of a Business - Add

Acquisition of a Business - Additional Information (Details) - USD ($)	Apr. 30, 2019	May 31, 2018	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill			$ 128,177,000	$ 54,562,000	$ 128,177,000	$ 54,562,000
Total assets			5,009,925,000		4,942,574,000
Trading securities			0		0
Total deposits			$ 3,808,516,000		$ 3,749,916,000
Oak Park River Forest
Business Acquisition [Line Items]
Business acquisition date of agreement			Apr. 30, 2019
Total assets			$ 323,500,000
Trading securities			30,800,000
Total loans			269,500,000
Total deposits			$ 285,700,000
Oak Park River Forest | Subsequent Event
Business Acquisition [Line Items]
Right to receive common stock upon conversion	7.9321
Consideration paid in cash	$ 6,100,000
Common stock outstanding value per share	$ 33.375
Common stock issued price per share	$ 20.02
Issuance of common shares	1,464,558
Value of common stock consideration	$ 29,300,000
Options to acquire common stock shares	35,870
Option to acquire common stock value	$ 4,200,000
First Evanston Bancorp, Inc.
Business Acquisition [Line Items]
Business acquisition date of agreement			May 31, 2018
Right to receive common stock upon conversion		3.994
Consideration paid in cash		$ 27,004,000
Common stock outstanding value per share		$ 16.136
Common stock issued price per share		$ 21.62
Issuance of common shares		6,682,850
Value of common stock consideration		$ 144,500,000
Options to acquire common stock shares		144,090
Options to acquire conversion of common stock shares		680,787
Option to acquire common stock value		$ 7,600,000
Total merger consideration		179,131,000
Stock issuance costs		852,000
Goodwill		$ 73,615,000
First Evanston Bancorp, Inc. | Non-interest Expense
Business Acquisition [Line Items]
Acquisition advisory expenses			$ 0	123,000
Core system conversion expenses			$ 1,500,000	$ 0

Acquisition of a Business - Sum

Acquisition of a Business - Summary of Fair Values of Assets and Liabilities Assumed as of Acquisition Date (Details) - USD ($) $ in Thousands	May 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Consideration paid
Goodwill		$ 128,177	$ 128,177	$ 54,562	$ 54,562
First Evanston Bancorp, Inc.
Assets
Cash and cash equivalents	$ 47,378
Securities available-for-sale	128,063
Restricted stock	1,360
Loans	916,011
Premises and equipment	15,890
Other intangible assets	22,276
Deferred tax assets, net	2,302
Other assets	8,845
Total assets acquired	1,142,125
Liabilities
Deposits	1,022,268
Junior subordinated debentures	8,497
Accrued expenses and other liabilities	5,844
Total liabilities assumed	1,036,609
Net assets acquired	105,516
Consideration paid
Common stock (6,682,850 shares issued at $21.62 per share)	144,483
Outstanding stock options converted to Byline stock options	7,644
Consideration paid in cash	27,004
Total consideration paid	179,131
Goodwill	$ 73,615

Acquisition of a Business - S_2

Acquisition of a Business - Summary of Fair Values of Assets and Liabilities Assumed as of Acquisition Date (Parenthetical) (Details) - Ridgestone	May 31, 2018$ / sharesshares
Business Acquisition [Line Items]
Stock issued (in shares) | shares	6,682,850
Stock issued (in dollars per share) | $ / shares	$ 21.62

Acquisition of a Business - S_3

Acquisition of a Business - Summary of Acquired Non-Impaired Loans as of Acquisition Date (Details) $ in Thousands	May 31, 2018USD ($)
Business Combinations [Abstract]
Fair value	$ 890,986
Gross contractual amounts receivable	1,057,374
Estimate of contractual cash flows not expected to be collected	36,544	[1]
Estimate of contractual cash flows expected to be collected	$ 1,020,830
[1]	Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default.

Acquisition of a Business - S_4

Acquisition of a Business - Summary of Unaudited Pro Forma Information for Results of Operations (Details) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2018USD ($)$ / shares
Business Combinations [Abstract]
Total revenues (net interest income and non-interest income) | $	$ 57,697
Net income | $	$ 10,458
Earnings per share—basic | $ / shares	$ 0.29
Earnings per share—diluted | $ / shares	$ 0.28

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Fair Values of Equity and Other Securities (Details) $ in Thousands	Mar. 31, 2019USD ($)
Schedule Of Equity And Other Securities [Line Items]
Equity and Other Securities, Amortized Cost	$ 7,216
Equity and Other Securities, Fair Value	7,216
Mutual Funds
Schedule Of Equity And Other Securities [Line Items]
Equity and Other Securities, Amortized Cost	2,882
Equity and Other Securities, Fair Value	2,882
Equity Securities
Schedule Of Equity And Other Securities [Line Items]
Equity and Other Securities, Amortized Cost	4,334
Equity and Other Securities, Fair Value	$ 4,334

Securities - Summary of Amort_2

Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 974,513	$ 834,254
Available-for-sale Securities, Gross Unrealized Gains	3,431	3,130
Available-for-sale Securities, Gross Unrealized Losses	(13,391)	(19,728)
Available-for-sale Securities, Fair Value	964,553	817,656
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	57,323	52,775
Available-for-sale Securities, Gross Unrealized Gains	162	81
Available-for-sale Securities, Gross Unrealized Losses	(98)	(189)
Available-for-sale Securities, Fair Value	57,387	52,667
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	187,458	187,427
Available-for-sale Securities, Gross Unrealized Gains	816	367
Available-for-sale Securities, Gross Unrealized Losses	(772)	(1,296)
Available-for-sale Securities, Fair Value	187,502	186,498
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	82,049	60,686
Available-for-sale Securities, Gross Unrealized Gains	749	133
Available-for-sale Securities, Gross Unrealized Losses	(231)	(586)
Available-for-sale Securities, Fair Value	82,567	60,233
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	347,166	284,038
Available-for-sale Securities, Gross Unrealized Gains	753	101
Available-for-sale Securities, Gross Unrealized Losses	(7,435)	(11,176)
Available-for-sale Securities, Fair Value	340,484	272,963
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	132,071	84,998
Available-for-sale Securities, Gross Unrealized Gains	814	199
Available-for-sale Securities, Gross Unrealized Losses	(1,219)	(1,576)
Available-for-sale Securities, Fair Value	131,666	83,621
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	100,400	93,543
Available-for-sale Securities, Gross Unrealized Gains	78	55
Available-for-sale Securities, Gross Unrealized Losses	(2,665)	(3,164)
Available-for-sale Securities, Fair Value	97,813	90,434
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	31,380	31,458
Available-for-sale Securities, Gross Unrealized Losses	(545)	(1,000)
Available-for-sale Securities, Fair Value	30,835	30,458
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	36,666	34,716
Available-for-sale Securities, Gross Unrealized Gains	59	67
Available-for-sale Securities, Gross Unrealized Losses	(426)	(610)
Available-for-sale Securities, Fair Value	$ 36,299	34,173
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost		4,613
Available-for-sale Securities, Gross Unrealized Gains		2,127
Available-for-sale Securities, Gross Unrealized Losses		(131)
Available-for-sale Securities, Fair Value		$ 6,609

Securities - Summary of Amort_3

Securities - Summary of Amortized Cost and Fair Values of Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	$ 4,425	$ 99,266
Held-to-maturity Securities, Gross Unrealized Gains	22	133
Held-to-maturity Securities, Gross Unrealized Losses	(16)	(1,660)
Held-to-maturity Securities, Fair Value	4,431	97,739
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	4,425	23,835
Held-to-maturity Securities, Gross Unrealized Gains	22	40
Held-to-maturity Securities, Gross Unrealized Losses	(16)	(210)
Held-to-maturity Securities, Fair Value	$ 4,431	23,665
Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost		40,082
Held-to-maturity Securities, Gross Unrealized Gains		93
Held-to-maturity Securities, Gross Unrealized Losses		(531)
Held-to-maturity Securities, Fair Value		39,644
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost		35,349
Held-to-maturity Securities, Gross Unrealized Losses		(919)
Held-to-maturity Securities, Fair Value		$ 34,430

Securities - Additional Informa

Securities - Additional Information (Details)	Jan. 01, 2019USD ($)	Mar. 31, 2019USD ($)Security	Mar. 31, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule Of Investments [Line Items]
Trading securities		$ 0		$ 0
Equity and other securities, at fair value		7,216,000
Available-for-sale-securities, sales		0	$ 0
Available-for-sale-securities, gains		0	0
Available-for-sale-securities, losses		0	0
Net gains or (losses) reclassified from accumulated other comprehensive income (loss) into earnings		0	$ 0
Carrying amount of securities pledged as collateral		$ 223,900,000		$ 244,700,000
Minimum
Schedule Of Investments [Line Items]
Percentage of shareholders equity for which securities holdings exceeds for no issuer other than U.S. Government and agencies		10.00%		10.00%
Federal Home Loan Bank Advances
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral		$ 0		$ 0
Public Fund Deposits
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral		177,300,000		197,800,000
Customer Repurchase Agreements
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral		$ 46,600,000		46,900,000
Available-for-sale Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security		161
Held-to-maturity Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security		4
ASU 2016-01
Schedule Of Investments [Line Items]
Reclassification from other comprehensive income to retained earnings	$ 1,400,000
Equity and other securities, at fair value				$ 6,600,000
ASU 2017-12
Schedule Of Investments [Line Items]
Reclassification of securities held-to-maturity to securities available-for-sale	$ 94,800,000

Securities - Summary of Gross U

Securities - Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Available-for-sale (Details) $ in Thousands	Mar. 31, 2019USD ($)Security	Dec. 31, 2018USD ($)Security
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	161	179
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 88,048	$ 191,761
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(410)	(2,441)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	549,125	427,243
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(12,981)	(17,287)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	637,173	619,004
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (13,391)	$ (19,728)
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	13	18
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 7,965	$ 23,835
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2)	(52)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	14,891	9,865
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(96)	(137)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	22,856	33,700
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (98)	$ (189)
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	20	25
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 38,421	$ 43,487
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(50)	(80)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	50,613	50,101
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(722)	(1,216)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	89,034	93,588
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (772)	$ (1,296)
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	30	56
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 542	$ 13,926
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1)	(97)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	20,376	18,563
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(230)	(489)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	20,918	32,489
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (231)	$ (586)
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	57	42
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 4,288
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(45)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 276,827	254,121
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(7,435)	(11,131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	276,827	258,409
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (7,435)	$ (11,176)
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	13	8
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 59,107
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(1,378)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 82,304	4,009
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(1,219)	(198)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	82,304	63,116
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,219)	$ (1,576)
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	11	9
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 25,364	$ 21,356
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(128)	(447)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	65,029	52,640
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(2,537)	(2,717)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	90,393	73,996
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (2,665)	$ (3,164)
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	5	5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 30,835	$ 30,458
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(545)	(1,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	30,835	30,458
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (545)	$ (1,000)
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	12	15
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 15,756	$ 25,762
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(229)	(342)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	8,250	4,642
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(197)	(268)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	24,006	30,404
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (426)	$ (610)
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security		1
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		$ 2,844
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value		2,844
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses		$ (131)

Securities - Summary of Gross_2

Securities - Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Held-to-maturity (Details) $ in Thousands	Mar. 31, 2019USD ($)Security	Dec. 31, 2018USD ($)Security
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Number of Securities | Security	4	46
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 36,251
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(711)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 2,605	42,862
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(16)	(949)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	2,605	79,113
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (16)	$ (1,660)
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Number of Securities | Security	4	23
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 8,127
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(58)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 2,605	8,792
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(16)	(152)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	2,605	16,919
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (16)	$ (210)
Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Number of Securities | Security		16
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 6,625
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(150)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		21,139
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(381)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value		27,764
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses		$ (531)
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Number of Securities | Security		7
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 21,499
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(503)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		12,931
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(416)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value		34,430
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses		$ (919)

Securities - Schedule of Amorti

Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Due in one year or less, Amortized Cost	$ 83,952
Available-for-sale Securities, Due from one to five years, Amortized Cost	161,739
Available-for-sale Securities, Due from five to ten years, Amortized Cost	91,146
Available-for-sale Securities, Due after ten years, Amortized Cost	26,659
Available-for-sale Securities, Amortized Cost	974,513	$ 834,254
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Due from one to five years, Amortized Cost	3,262
Held-to-maturity Securities, Due from five to ten years, Amortized Cost	1,163
Held-to-maturity Securities, Amortized Cost	4,425	99,266
Equity and Other Securities, Amortized Cost [Abstract]
Equity and Other Securities, Due after ten years, Amortized Cost	695
Equity and Other Securities, Not due at single maturity, Amortized Cost	6,521
Equity and Other Securities, Amortized Cost	7,216
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Due in one year or less, Fair Value	83,767
Available-for-sale Securities, Due from one to five years, Fair Value	161,679
Available-for-sale Securities, Due from five to ten years, Fair Value	91,405
Available-for-sale Securities, Due after ten years, Fair Value	26,904
Available-for-sale Securities, Fair Value, Total	964,553	817,656
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Due from one to five years, Fair Value	3,264
Held-to-maturity Securities, Due from five to ten years, Fair Value	1,167
Held-to-maturity securities, Fair Value, Total	4,431	$ 97,739
Equity and Other Securities, Fair Value [Abstract]
Equity and Other Securities, Due after ten years, Fair Value	695
Equity and Other Securities, Not due at single maturity, Fair Value	6,521
Equity and Other Securities, Fair Value	7,216
Mortgage-Backed Securities
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Not due at single maturity, Amortized Cost	611,017
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	$ 600,798

Loan and Lease Receivables - Sc

Loan and Lease Receivables - Schedule of Outstanding Loan and Lease Receivables (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,565,105	$ 3,499,463
Net unamortized deferred fees and costs	(764)	(1,293)
Initial direct costs	3,225	3,456
Allowance for loan and lease losses	(27,106)	(25,201)	$ (17,640)	$ (16,706)
Net loans and leases	3,540,460	3,476,425
Lease financing receivables
Net minimum lease payments	203,238	204,646
Unguaranteed residual values	1,511	1,535
Unearned income	(18,006)	(18,384)
Total lease financing receivables	186,743	187,797
Initial direct costs	3,225	3,456
Lease financial receivables before allowance for lease losses	189,968	191,253
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,262,236	1,261,594
Allowance for loan and lease losses	(6,660)	(7,540)	(5,319)	(4,794)
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	699,088	704,899
Allowance for loan and lease losses	(1,970)	(1,751)	(1,564)	(1,638)
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	214,562	186,258
Allowance for loan and lease losses	(536)	(466)	(201)	(222)
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,189,710	1,145,240
Allowance for loan and lease losses	(15,630)	(12,932)	(7,763)	(7,418)
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,766	13,675
Allowance for loan and lease losses	(63)	(49)	(61)	(41)
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	186,743	187,797
Allowance for loan and lease losses	$ (2,247)	$ (2,463)	$ (2,732)	$ (2,593)

Loan and Lease Receivables - Ad

Loan and Lease Receivables - Additional Information (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018	May 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,565,105,000	$ 3,499,463,000
Loans held for sale pledged as security for borrowings	1,400,000,000	1,400,000,000
Allowance for loan and lease losses	27,106,000	25,201,000		$ 17,640,000	$ 16,706,000
Acquired Impaired Loans
Accounts Notes And Loans Receivable [Line Items]
Loans acquired	0	0	$ 25,025,000
Allowance for loan and lease losses	2,800,000	2,700,000
Acquired Non-Impaired Loans and Leases | First Evanston
Accounts Notes And Loans Receivable [Line Items]
Loans acquired	891,000,000
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,766,000	13,675,000
Overdraft deposits reclassified as loans	1,100,000	1,700,000
Allowance for loan and lease losses	63,000	49,000		$ 61,000	$ 41,000
U.S. Government Guaranteed Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 129,000,000	$ 108,700,000

Loan and Lease Receivables - Su

Loan and Lease Receivables - Summary of Minimum Annual Lease Payments for Lease Financing Receivables (Details) $ in Thousands	Mar. 31, 2019USD ($)
Receivables [Abstract]
2019	$ 56,181
2020	62,573
2021	43,337
2022	27,072
2023	12,269
Thereafter	1,806
Total	$ 203,238

Loan and Lease Receivables - _2

Loan and Lease Receivables - Summary of Balances for Each Respective Loan and Lease Category (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,567,566	$ 3,501,626	$ 2,280,418
Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	2,487,534	2,237,798
Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	263,411	277,542
Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	816,621	986,286
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,262,283	1,261,607	840,869
Commercial Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	738,832	652,234
Commercial Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	141,199	146,808
Commercial Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	382,252	462,565
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	699,036	704,902	568,159
Residential Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	494,877	466,309
Residential Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	106,764	113,934
Residential Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	97,395	124,659
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	213,659	185,349	117,070
Construction, Land Development, and Other Land | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	181,427	144,128
Construction, Land Development, and Other Land | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	3,111	3,779
Construction, Land Development, and Other Land | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	29,121	37,442
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,189,818	1,144,797	568,729
Commercial and Industrial | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	900,709	803,508
Commercial and Industrial | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	11,963	12,617
Commercial and Industrial | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	277,146	328,672
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,802	13,718	4,130
Installment and Other | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	11,082	11,718
Installment and Other | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	374	404
Installment and Other | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,346	1,596
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	189,968	191,253	$ 181,461
Lease Financing Receivables | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	160,607	159,901
Lease Financing Receivables | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 29,361	$ 31,352

Loan and Lease Receivables - Es

Loan and Lease Receivables - Estimated Fair Value of Impaired Loans Acquired at Acquisition (Details) - Acquired Impaired Loans - USD ($)	Mar. 31, 2019	Dec. 31, 2018	May 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Undiscounted contractual cash flows			$ 33,594,000
Undiscounted cash flows not expected to be collected (non-accretable difference)			5,003,000
Undiscounted cash flows expected to be collected			28,591,000
Accretable yield at acquisition			(3,566,000)
Estimated fair value of impaired loans acquired at acquisition	$ 0	$ 0	$ 25,025,000

Loan and Lease Receivables - _3

Loan and Lease Receivables - Summary of Outstanding Balance and Carrying Amount of All Acquired Impaired Loans (Details) - Acquired Impaired Loans - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	$ 378,251	$ 428,768
Carrying Value	263,411	277,542
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	194,328	216,137
Carrying Value	141,199	146,808
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	155,075	173,962
Carrying Value	106,764	113,934
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	10,849	11,962
Carrying Value	3,111	3,779
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	16,794	24,972
Carrying Value	11,963	12,617
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	1,205	1,735
Carrying Value	$ 374	$ 404

Loan and Lease Receivables - _4

Loan and Lease Receivables - Summary of Changes in Accretable Yield for Acquired Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Receivables [Abstract]
Beginning balance	$ 37,115	$ 36,446
Accretion to interest income	(5,250)	(5,691)
Reclassification from (to) nonaccretable difference, net	(2,525)	8,545
Ending balance	$ 29,340	$ 39,300

Loan and Lease Receivables - _5

Loan and Lease Receivables - Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-impaired Loans and Leases (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	$ 3,567,566	$ 3,501,626	$ 2,280,418
Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	838,939	1,018,921
Loans and leases	816,621	986,286
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,262,283	1,261,607	840,869
Commercial Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	391,806	473,262
Loans and leases	382,252	462,565
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	699,036	704,902	568,159
Residential Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	99,828	127,478
Loans and leases	97,395	124,659
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	213,659	185,349	117,070
Construction, Land Development, and Other Land | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	30,081	38,494
Loans and leases	29,121	37,442
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,189,818	1,144,797	568,729
Commercial and Industrial | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	284,997	344,879
Loans and leases	277,146	328,672
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	12,802	13,718	4,130
Installment and Other | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	1,375	1,831
Loans and leases	1,346	1,596
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	189,968	191,253	$ 181,461
Lease Financing Receivables | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	30,852	32,977
Loans and leases	$ 29,361	$ 31,352

Allowance for Loan and Lease _3

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Allowance for loan and lease losses
Beginning balance	$ 25,201	$ 16,706
Provisions (releases)	3,999	5,115
Charge-offs	(2,348)	(4,422)
Recoveries	254	241
Ending balance	27,106	17,640
Ending balance:
Individually evaluated for impairment			$ 7,559		$ 4,702
Collectively evaluated for impairment			16,701		9,409
Allowance for loan and lease losses	27,106	16,706	27,106	$ 25,201	17,640
Loans and leases ending balance:
Individually evaluated for impairment			43,798		27,016
Collectively evaluated for impairment			3,260,357		1,941,928
Total loans and leases			3,567,566	3,501,626	2,280,418
Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality			2,846		3,529
Loans and leases ending balance:
Loans acquired with deteriorated credit quality			263,411		311,474
Commercial Real Estate
Allowance for loan and lease losses
Beginning balance	7,540	4,794
Provisions (releases)	442	934
Charge-offs	(1,351)	(409)
Recoveries	29
Ending balance	6,660	5,319
Ending balance:
Individually evaluated for impairment			1,403		1,572
Collectively evaluated for impairment			4,141		1,827
Allowance for loan and lease losses	7,540	4,794	6,660	7,540	5,319
Loans and leases ending balance:
Individually evaluated for impairment			17,354		12,375
Collectively evaluated for impairment			1,103,730		670,538
Total loans and leases			1,262,283	1,261,607	840,869
Commercial Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality			1,116		1,920
Loans and leases ending balance:
Loans acquired with deteriorated credit quality			141,199		157,956
Residential Real Estate
Allowance for loan and lease losses
Beginning balance	1,751	1,638
Provisions (releases)	218	(74)
Recoveries	1
Ending balance	1,970	1,564
Ending balance:
Individually evaluated for impairment			34		153
Collectively evaluated for impairment			1,516		1,036
Allowance for loan and lease losses	1,751	1,638	1,970	1,751	1,564
Loans and leases ending balance:
Individually evaluated for impairment			2,060		2,029
Collectively evaluated for impairment			590,212		426,272
Total loans and leases			699,036	704,902	568,159
Residential Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality			420		375
Loans and leases ending balance:
Loans acquired with deteriorated credit quality			106,764		139,858
Construction, Land Development, and Other Land
Allowance for loan and lease losses
Beginning balance	466	222
Provisions (releases)	70	397
Charge-offs		(418)
Ending balance	536	201
Ending balance:
Collectively evaluated for impairment			536		177
Allowance for loan and lease losses	466	222	536	466	201
Loans and leases ending balance:
Collectively evaluated for impairment			210,548		111,914
Total loans and leases			213,659	185,349	117,070
Construction, Land Development, and Other Land | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					24
Loans and leases ending balance:
Loans acquired with deteriorated credit quality			3,111		5,156
Commercial and Industrial
Allowance for loan and lease losses
Beginning balance	12,932	7,418
Provisions (releases)	3,032	3,424
Charge-offs	(352)	(3,085)
Recoveries	18	6
Ending balance	15,630	7,763
Ending balance:
Individually evaluated for impairment			6,122		2,963
Collectively evaluated for impairment			8,200		3,626
Allowance for loan and lease losses	12,932	7,418	15,630	12,932	7,763
Loans and leases ending balance:
Individually evaluated for impairment			24,384		12,598
Collectively evaluated for impairment			1,153,471		548,076
Total loans and leases			1,189,818	1,144,797	568,729
Commercial and Industrial | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality			1,308		1,174
Loans and leases ending balance:
Loans acquired with deteriorated credit quality			11,963		8,055
Installment and Other
Allowance for loan and lease losses
Beginning balance	49	41
Provisions (releases)	14	20
Ending balance	63	61
Ending balance:
Individually evaluated for impairment					14
Collectively evaluated for impairment			61		11
Allowance for loan and lease losses	49	41	63	49	61
Loans and leases ending balance:
Individually evaluated for impairment					14
Collectively evaluated for impairment			12,428		3,667
Total loans and leases			12,802	13,718	4,130
Installment and Other | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality			2		36
Loans and leases ending balance:
Loans acquired with deteriorated credit quality			374		449
Lease Financing Receivables
Allowance for loan and lease losses
Beginning balance	2,463	2,593
Provisions (releases)	223	414
Charge-offs	(645)	(510)
Recoveries	206	235
Ending balance	2,247	2,732
Ending balance:
Collectively evaluated for impairment			2,247		2,732
Allowance for loan and lease losses	$ 2,463	$ 2,593	2,247	2,463	2,732
Loans and leases ending balance:
Collectively evaluated for impairment			189,968		181,461
Total loans and leases			$ 189,968	$ 191,253	$ 181,461

Allowance for Loan and Lease _4

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 1,900,000	$ 934,000
Commitments outstanding on troubled debt restructurings	500,000		$ 500,000
Recorded investment in troubled debt restructurings that subsequently defaulted within twelve months	0	0
Reserve for unfunded commitments	1,100,000		$ 1,200,000
Provisions for (credits to) unfunded commitments	(156,000)	113,000
Charge-offs or recoveries related to reserve for unfunded commitments	0	0
Individually Evaluated For Impairment
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	910,000	737,000
Collectively Evaluated For Impairment
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	884,000	542,000
Acquired Impaired Loans
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 111,000	$ (345,000)

Allowance for Loan and Lease _5

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Recorded Investment, Unpaid Principal Balance, and Related Allowance for Loans and Leases Considered Impaired (Details) - Loans Excluding Acquired Impaired Loans - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable Impaired [Line Items]
Recorded Investment	$ 43,798	$ 35,914
Unpaid Principal Balance	48,587	41,231
Related Allowance	7,559	6,649
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	11,643	6,110
Recorded Investment, With an allowance recorded	5,711	5,873
Unpaid Principal Balance, With no related allowance recorded	13,669	7,693
Unpaid Principal Balance, With an allowance recorded	5,959	6,313
Related Allowance	1,403	2,191
Residential Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	1,838	1,886
Recorded Investment, With an allowance recorded	222	251
Unpaid Principal Balance, With no related allowance recorded	1,841	1,858
Unpaid Principal Balance, With an allowance recorded	222	253
Related Allowance	34	61
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	10,907	11,193
Recorded Investment, With an allowance recorded	13,477	10,601
Unpaid Principal Balance, With no related allowance recorded	12,785	13,961
Unpaid Principal Balance, With an allowance recorded	14,111	11,153
Related Allowance	$ 6,122	$ 4,397

Allowance for Loan and Lease _6

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Average Recorded Investment and Interest Income Recognized for Loans and Leases Considered Impaired (Details) - Loans Excluding Acquired Impaired Loans - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Financing Receivable Impaired [Line Items]
Average Recorded Investment	$ 37,056	$ 29,731
Interest Income Recognized	462	315
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	7,345	9,039
Average Recorded Investment, With an allowance recorded	5,186	4,122
Interest Income Recognized, With no related allowance recorded	119	103
Interest Income Recognized, With an allowance recorded	48	37
Residential Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	1,541	1,930
Average Recorded Investment, With an allowance recorded	226	351
Interest Income Recognized, With no related allowance recorded	13	10
Interest Income Recognized, With an allowance recorded	2	1
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	11,381	7,300
Average Recorded Investment, With an allowance recorded	11,377	6,975
Interest Income Recognized, With no related allowance recorded	126	62
Interest Income Recognized, With an allowance recorded	$ 154	102
Installment and Other
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With an allowance recorded		$ 14

Allowance for Loan and Lease _7

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 3,567,566	$ 3,501,626	$ 2,280,418
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,262,283	1,261,607	840,869
Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	699,036	704,902	568,159
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	213,659	185,349	117,070
Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,189,818	1,144,797	568,729
Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,802	13,718	4,130
Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	189,968	191,253	$ 181,461
Loans Excluding Acquired Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,304,155	3,224,084
Loans Excluding Acquired Impaired Loans | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,121,084	1,114,799
Loans Excluding Acquired Impaired Loans | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	592,272	590,968
Loans Excluding Acquired Impaired Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	210,548	181,570
Loans Excluding Acquired Impaired Loans | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,177,855	1,132,180
Loans Excluding Acquired Impaired Loans | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,428	13,314
Loans Excluding Acquired Impaired Loans | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	189,968	191,253
Loans Excluding Acquired Impaired Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,911,786	2,870,431
Loans Excluding Acquired Impaired Loans | Pass | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	996,417	1,009,041
Loans Excluding Acquired Impaired Loans | Pass | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	554,892	553,665
Loans Excluding Acquired Impaired Loans | Pass | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	172,720	147,123
Loans Excluding Acquired Impaired Loans | Pass | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	989,123	962,291
Loans Excluding Acquired Impaired Loans | Pass | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,404	9,997
Loans Excluding Acquired Impaired Loans | Pass | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	186,230	188,314
Loans Excluding Acquired Impaired Loans | Watch
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	284,713	253,552
Loans Excluding Acquired Impaired Loans | Watch | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	87,343	76,276
Loans Excluding Acquired Impaired Loans | Watch | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	29,753	29,522
Loans Excluding Acquired Impaired Loans | Watch | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	37,828	31,376
Loans Excluding Acquired Impaired Loans | Watch | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	129,730	112,996
Loans Excluding Acquired Impaired Loans | Watch | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	17	3,302
Loans Excluding Acquired Impaired Loans | Watch | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	42	80
Loans Excluding Acquired Impaired Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	61,315	62,437
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	19,904	17,602
Loans Excluding Acquired Impaired Loans | Special Mention | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	5,410	5,656
Loans Excluding Acquired Impaired Loans | Special Mention | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases		3,071
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	33,489	34,314
Loans Excluding Acquired Impaired Loans | Special Mention | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,512	1,794
Loans Excluding Acquired Impaired Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	45,485	37,417
Loans Excluding Acquired Impaired Loans | Substandard | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	17,420	11,880
Loans Excluding Acquired Impaired Loans | Substandard | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,217	2,125
Loans Excluding Acquired Impaired Loans | Substandard | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	25,513	22,579
Loans Excluding Acquired Impaired Loans | Substandard | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	7	15
Loans Excluding Acquired Impaired Loans | Substandard | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	328	818
Loans Excluding Acquired Impaired Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	856	247
Loans Excluding Acquired Impaired Loans | Doubtful | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 856	$ 247

Allowance for Loan and Lease _8

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Contractual Delinquency Information (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	$ 3,567,566	$ 3,501,626	$ 2,280,418
Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,262,283	1,261,607	840,869
Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	699,036	704,902	568,159
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	213,659	185,349	117,070
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,189,818	1,144,797	568,729
Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	12,802	13,718	4,130
Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	189,968	191,253	$ 181,461
Acquired Non-Impaired and Originated Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	75,242	50,297
Non-accrual	28,539	25,834
Current	3,228,913	3,173,787
Total loans and leases	3,304,155	3,224,084
Acquired Non-Impaired and Originated Loans | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	43,060	19,697
Acquired Non-Impaired and Originated Loans | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,643	4,766
Acquired Non-Impaired and Originated Loans | Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	28,776	18,288
Non-accrual	9,677	9,484
Current	1,092,308	1,096,511
Total loans and leases	1,121,084	1,114,799
Acquired Non-Impaired and Originated Loans | Commercial Real Estate | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	17,155	6,659
Acquired Non-Impaired and Originated Loans | Commercial Real Estate | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,944	2,145
Acquired Non-Impaired and Originated Loans | Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	4,655	7,014
Non-accrual	2,070	1,815
Current	587,617	583,954
Total loans and leases	592,272	590,968
Acquired Non-Impaired and Originated Loans | Residential Real Estate | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,337	4,488
Acquired Non-Impaired and Originated Loans | Residential Real Estate | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,248	711
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	12,009
Current	198,539	181,570
Total loans and leases	210,548	181,570
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	12,009
Acquired Non-Impaired and Originated Loans | Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	27,502	21,137
Non-accrual	15,931	13,932
Current	1,150,353	1,111,043
Total loans and leases	1,177,855	1,132,180
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	11,454	5,829
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	117	1,376
Acquired Non-Impaired and Originated Loans | Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	23	1,948
Non-accrual	5	12
Current	12,405	11,366
Total loans and leases	12,428	13,314
Acquired Non-Impaired and Originated Loans | Installment and Other | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	12	1,932
Acquired Non-Impaired and Originated Loans | Installment and Other | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	6	4
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,277	1,910
Non-accrual	856	591
Current	187,691	189,343
Total loans and leases	189,968	191,253
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,093	789
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 328	$ 530

Allowance for Loan and Lease _9

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of TDR's by Loan Category (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019USD ($)Loan	Dec. 31, 2018USD ($)Loan
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	25	22
Pre-Modification Outstanding Recorded Investment	$ 11,482	$ 11,039
Post-Modification Outstanding Recorded Investment	9,040	9,127
Charge-offs	2,442	1,912
Specific Reserves	$ 1,635	$ 2,246
Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	8	7
Pre-Modification Outstanding Recorded Investment	$ 1,921	$ 1,813
Post-Modification Outstanding Recorded Investment	1,921	1,813
Specific Reserves	$ 223	$ 213
Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	17	15
Pre-Modification Outstanding Recorded Investment	$ 9,561	$ 9,226
Post-Modification Outstanding Recorded Investment	7,119	7,314
Charge-offs	2,442	1,912
Specific Reserves	$ 1,412	$ 2,033
Commercial Real Estate | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	4	4
Pre-Modification Outstanding Recorded Investment	$ 1,486	$ 1,508
Post-Modification Outstanding Recorded Investment	1,486	1,508
Specific Reserves	$ 124	$ 113
Commercial Real Estate | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	9	9
Pre-Modification Outstanding Recorded Investment	$ 2,690	$ 2,512
Post-Modification Outstanding Recorded Investment	2,119	2,471
Charge-offs	571	41
Specific Reserves	$ 141	$ 743
Commercial and Industrial | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	2	2
Pre-Modification Outstanding Recorded Investment	$ 216	$ 191
Post-Modification Outstanding Recorded Investment	216	191
Specific Reserves	$ 99	$ 100
Commercial and Industrial | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	8	6
Pre-Modification Outstanding Recorded Investment	$ 6,871	$ 6,714
Post-Modification Outstanding Recorded Investment	5,000	4,843
Charge-offs	1,871	1,871
Specific Reserves	$ 1,271	$ 1,290
Residential Real Estate | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	2	1
Pre-Modification Outstanding Recorded Investment	$ 219	$ 114
Post-Modification Outstanding Recorded Investment	$ 219	$ 114

Allowance for Loan and Lease_10

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Loans Modified as Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Receivables [Abstract]
Beginning balance	$ 1,813	$ 1,061
Additions	113
Net payments	(5)	(24)
Ending balance	1,921	1,037
Beginning balance	7,314	1,569
Additions	246
Net payments	89	(332)
Charge-offs	(530)	(144)
Ending balance	7,119	1,093
Total troubled debt restructurings	$ 9,040	$ 2,130

Servicing Assets - Activity for

Servicing Assets - Activity for Servicing Assets and Related Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Transfers And Servicing [Abstract]
Beginning balance	$ 19,693	$ 21,400
Additions, net	1,102	2,102
Changes in fair value	(1,261)	(1,887)
Ending balance	$ 19,534	$ 21,615

Servicing Assets - Unpaid Princ

Servicing Assets - Unpaid Principal Balances of Loans Serviced for Others (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 1,264,441	$ 1,258,099
SBA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	1,160,938	1,151,915
USDA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 103,503	$ 106,184

Servicing Assets - Additional I

Servicing Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Changes in fair value of servicing assets	$ (1,261)	$ (1,887)
Loan Servicing Revenue [Member]
Accounts Notes And Loans Receivable [Line Items]
Fees and charges	$ 2,539	$ 2,450

Other Real Estate Owned - Chang

Other Real Estate Owned - Change in Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Banking And Thrift [Abstract]
Other real estate owned, beginning balance	$ 5,314	$ 10,626
Net additions to OREO	230	1,044
Proceeds from sales of OREO	(628)	(1,263)
Gains (losses) on sales of OREO	(33)	140
Valuation adjustments	(84)	(81)
Other real estate owned, ending balance	$ 4,799	$ 10,466

Other Real Estate Owned - Addit

Other Real Estate Owned - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 4,799,000	$ 10,466,000	$ 5,314,000	$ 10,626,000
Residential consumer mortgage loans in process of foreclosure	2,700,000		2,300,000
Proceeds from sale of internally financed sales of OREO	183,000	$ 0
Residential Real Estate
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 700,000		$ 838,000

Goodwill, Core Deposit Intang_3

Goodwill, Core Deposit Intangible and Other Intangible Assets - Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance, Goodwill	$ 128,177	$ 54,562
Ending balance, Goodwill	128,177	54,562
Amortization	(1,773)	(767)
Core Deposits
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	30,360	16,720
Amortization	(1,706)	(761)
Ending balance	28,654	15,959
Accumulated amortization	$ 20,592	$ 14,227
Weighted average remaining amortization period	6 years 7 months 6 days	5 years 4 months 24 days
Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 3,059
Amortization	(67)
Ending balance	2,992
Accumulated amortization	$ 224
Weighted average remaining amortization period	11 years 2 months 12 days

Goodwill, Core Deposit Intang_4

Goodwill, Core Deposit Intangible and Other Intangible Assets - Estimated Amortization Expense for Core Deposit Intangible, Customer Relationship Intangible and Other Intangible Assets Recognized (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
2019	$ 5,153
2020	6,476
2021	6,025
2022	5,578
2023	3,645
Thereafter	4,769
Total	$ 31,646	$ 33,419

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2017	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Effective tax rate	27.60%	16.30%
Corporate federal income tax rate	21.00%		35.00%
Net income tax benefit		$ (724,000)
Deferred tax assets, net	$ 30,500,000			$ 35,600,000

Deposits - Composition of Depos

Deposits - Composition of Deposits (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Non-interest-bearing demand deposits	$ 1,163,255	$ 1,192,873
Interest-bearing checking accounts	305,393	296,339
Money market demand accounts	611,634	640,401
Other savings	468,524	476,418
Time deposits (below $250,000)	967,999	911,603
Time deposits ($250,000 and above)	291,711	232,282
Total deposits	$ 3,808,516	$ 3,749,916

Deposits - Additional Informati

Deposits - Additional Information (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Brokered deposits	$ 70,000,000	$ 50,000,000

Federal Home Loan Bank Advanc_3

Federal Home Loan Bank Advances - Summary of FHLB Advances (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank advances	$ 425,000	$ 425,000
Weighted average cost	2.59%	2.56%

Federal Home Loan Bank Advanc_4

Federal Home Loan Bank Advances - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank, total fixed-rate advances	$ 370,000,000
Federal home loan bank, total variable rate advances	$ 55,000,000
Federal home loan bank advances, Variable interest rate	2.47%
Federal home loan bank variable rate advances, maturity date	2019-05
Federal home loan bank, required investment conversion ratio	0.045
Additional borrowing capacity from FHLB	$ 1,300,000,000	$ 1,300,000,000
Federal home loan bank advances maximum borrowing capacity as percentage of total assets	35.00%
Minimum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.56%
Federal home loan bank fixed rate advances, maturity date	2019-04
Maximum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.61%
Federal home loan bank fixed rate advances, maturity date	2019-06

Other Borrowings - Summary of O

Other Borrowings - Summary of Other Borrowings (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Securities sold under agreements to repurchase	$ 34,369	$ 34,166
Total	$ 34,369	$ 34,166

Other Borrowings - Additional I

Other Borrowings - Additional Information (Details) - USD ($)	Apr. 30, 2019	Oct. 11, 2018	Jul. 31, 2017	Mar. 31, 2019	Dec. 31, 2018	Apr. 30, 2017	Oct. 13, 2016
Line Of Credit Facility [Line Items]
Repayment of lines of credit			$ 16,200,000
Short-term credit lines available for use, outstanding				$ 0	$ 0
Subsequent Event
Line Of Credit Facility [Line Items]
Line of credit facility, amount	$ 5,700,000
LIBOR Rate | Subsequent Event
Line Of Credit Facility [Line Items]
Interest rate spread	2.25%
Ridgestone | Correspondent Bank | Credit agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount							$ 30,000,000
Ridgestone | Correspondent Bank | Amended Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, revolving credit conversion to non-revolving line of credit, description				In April 2017, the revolving line of credit was amended to a non-revolving line of credit as long as the outstanding balance exceeds $5.0 million.
Line of credit facility, revolving credit conversion to non-revolving line of credit, threshold amount						$ 5,000,000
Threshold amount for conversion of line of credit into revolving line of credit						5,000,000
Revolving line of credit facility, maximum borrowing capacity						$ 5,000,000
Line of credit facility, maturity date				Oct. 11, 2018
Ridgestone | Correspondent Bank | Amended Credit Agreement | LIBOR Rate
Line Of Credit Facility [Line Items]
Interest rate spread				2.50%
Ridgestone | Correspondent Bank | Amended Credit Agreement | Prime Rate
Line Of Credit Facility [Line Items]
Interest rate spread				0.25%
Ridgestone | Correspondent Bank | Third Amendment Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount		$ 10,000,000		$ 0	$ 0
Line of credit facility, extended maturity date		Oct. 10, 2019
Line of credit facility, interest rate terms		The amended revolving line of credit bears interest at either the LIBOR plus 225 basis points or the Prime Rate minus 50 basis points, based on the Company’s election, which is required to be communicated at least three business days prior to the commencement of an interest period. If the Company fails to provide timely notification, the interest rate will be Prime Rate minus 50 basis points. At March 31, 2019 and December 31, 2018, the line of credit has not been drawn upon, so an interest rate option has not been selected
Ridgestone | Correspondent Bank | Third Amendment Revolving Credit Agreement | LIBOR Rate
Line Of Credit Facility [Line Items]
Interest rate spread		2.25%
Ridgestone | Correspondent Bank | Third Amendment Revolving Credit Agreement | Prime Rate
Line Of Credit Facility [Line Items]
Interest rate spread		0.50%

Other Borrowings - Summary of S

Other Borrowings - Summary of Short-term Credit Lines Available for Use (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Federal Reserve Bank of Chicago Discount Window Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 314,229	$ 293,613
Available Federal Funds Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 85,000	$ 55,000

Junior Subordinated Debenture_2

Junior Subordinated Debentures - Junior Subordinated Debentures by Issuance (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	$ 46,500	$ 46,500
Total liability, at carrying value	36,912	36,768
Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	35,000	35,000
RidgeStone Capital Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	1,500	1,500
First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	10,000	10,000
Junior Subordinated Debentures
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Discount	$ (9,588)	$ (9,732)
Junior Subordinated Debentures | Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 17, 2034
Contractual Rate	5.40%	5.58%
Junior Subordinated Debentures | Metropolitan Statutory Trust 1 | Three-month LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.79%	2.79%
Junior Subordinated Debentures | RidgeStone Capital Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Jun. 30, 2033
Contractual Rate	6.38%	6.38%
Junior Subordinated Debentures | RidgeStone Capital Trust I | Five-year LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Five-year LIBOR
Interest Rate Spread	3.50%	3.50%
Junior Subordinated Debentures | First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 15, 2035
Contractual Rate	4.39%	4.57%
Junior Subordinated Debentures | First Evanston Bancorp Trust I | Three-month LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.78%	1.78%

Junior Subordinated Debenture_3

Junior Subordinated Debentures - Additional Information (Details) - USD ($)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal amount	$ 46,500,000	$ 46,500,000
Accrued interest payable	4,390,000	3,484,000
Metropolitan Statutory Trust 1
Debt Instrument [Line Items]
Principal amount	$ 35,000,000	$ 35,000,000
Metropolitan Statutory Trust 1 | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	5.40%	5.58%
Accrued interest payable	$ 76,000	$ 84,000
Metropolitan Statutory Trust 1 | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread	2.79%	2.79%
RidgeStone Capital Trust I
Debt Instrument [Line Items]
Principal amount	$ 1,500,000	$ 1,500,000
RidgeStone Capital Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	6.38%	6.38%
Accrued interest payable	$ 0	$ 0
RidgeStone Capital Trust I | Junior Subordinated Debentures | Five-year LIBOR
Debt Instrument [Line Items]
Interest rate spread	3.50%	3.50%
First Evanston Bancorp Trust I
Debt Instrument [Line Items]
Principal amount	$ 10,000,000	$ 10,000,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	4.39%	4.57%
Accrued interest payable	$ 20,000	$ 21,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread	1.78%	1.78%

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Summary of Minimum Annual Rental Commitments for Operating Leases (Details) $ in Thousands	Mar. 31, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
2019	$ 2,714
2020	3,221
2021	2,961
2022	1,954
2023	1,012
Thereafter	3,069
Total	$ 14,931

Commitments and Contingent Li_4

Commitments and Contingent Liabilities - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended
	Jun. 30, 2018	Mar. 31, 2019	Mar. 31, 2018
Commitments And Contingencies Liabilities [Line Items]
Rental expenses		$ 1,300,000	$ 1,200,000
Sublease income		181,000	170,000
Minimum rental to be received in future on subleases		$ 1,600,000
Sublease contract maturity year		2025
Data processing		$ 3,273,000	$ 2,301,000
Fixed rate loan commitments maturity year		2042
Variable rate loan commitments maturity year		2048
Maximum
Commitments And Contingencies Liabilities [Line Items]
Commitments to make loans period		90 days
Loan commitments fixed interest rate		19.50%
Loan commitments variable interest rate		10.00%
Minimum
Commitments And Contingencies Liabilities [Line Items]
Loan commitments fixed interest rate		2.50%
Loan commitments variable interest rate		2.88%
Contract termination
Commitments And Contingencies Liabilities [Line Items]
Data processing	$ 8,100,000
Remaining data processing cost balance		$ 0

Commitments and Contingent Li_5

Commitments and Contingent Liabilities - Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	$ 82,666	$ 76,081
Variable Rate	909,495	963,062
Commitments to Extend Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	80,916	74,099
Variable Rate	875,341	928,991
Letters of Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	1,750	1,982
Variable Rate	$ 34,154	$ 34,071

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Financial Assets And Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 964,553	$ 817,656
Servicing assets, at fair value	19,534	19,693	$ 21,615	$ 21,400
Derivative assets	9,788	10,740
Derivative liabilities	5,984	4,243
U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	57,387	52,667
U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	187,502	186,498
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	82,567	60,233
Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	36,299	34,173
Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value		6,609
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	19,534	19,693
Derivative assets	9,788	10,740
Derivative liabilities	5,984	4,243
Fair Value, Measurements, Recurring | Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	2,882
Fair Value, Measurements, Recurring | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	4,334
Fair Value, Measurements, Recurring | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	57,387	52,667
Fair Value, Measurements, Recurring | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	187,502	186,498
Fair Value, Measurements, Recurring | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	82,567	60,233
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Residential | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	340,484	272,963
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Residential | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	131,666	83,621
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Commercial | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	97,813	90,434
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Commercial | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	30,835	30,458
Fair Value, Measurements, Recurring | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	36,299	34,173
Fair Value, Measurements, Recurring | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value		6,609
Fair Value, Measurements, Recurring | Level 1 | Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	2,882
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	57,387	52,667
Fair Value, Measurements, Recurring | Level 1 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value		2,844
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	9,788	10,740
Derivative liabilities	5,984	4,243
Fair Value, Measurements, Recurring | Level 2 | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	3,639
Fair Value, Measurements, Recurring | Level 2 | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	187,502	186,498
Fair Value, Measurements, Recurring | Level 2 | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	82,372	60,038
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Residential | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	340,484	272,963
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Residential | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	131,666	83,621
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Commercial | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	97,813	90,434
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Commercial | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	30,835	30,458
Fair Value, Measurements, Recurring | Level 2 | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	36,299	34,173
Fair Value, Measurements, Recurring | Level 2 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value		3,074
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	19,534	19,693
Fair Value, Measurements, Recurring | Level 3 | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	695
Fair Value, Measurements, Recurring | Level 3 | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 195	195
Fair Value, Measurements, Recurring | Level 3 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value		$ 691

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) - USD ($)	Mar. 31, 2019	Mar. 31, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Fair value, assets, to or from level 3 transfers, amount	$ 0	$ 0
Fair value, liabilities, to or from level 3 transfers, amount	0	0
Fair value, equity, to or from level 3 transfers, amount	$ 0	$ 0

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Financial Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Investment Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	$ 886	$ 1,052
Amortization	1	1
Change in unrealized gain		14
Change in fair value	3
Balance, end of period	890	1,067
Servicing Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	19,693	21,400
Additions, net	1,102	2,102
Change in fair value	(1,261)	(1,887)
Balance, end of period	$ 19,534	$ 21,615

Fair Value Measurement - Summ_3

Fair Value Measurement - Summary of Unobservable Inputs Used in Fair Value Measurements on Recurring Basis Categorized Within Level 3 of Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring - Level 3	3 Months Ended
	Mar. 31, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Expected weighted average loan life	1 month 6 days
Minimum | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.071
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected weighted average loan life	10 years 6 months
Maximum | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.218
Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected weighted average loan life	5 years
Weighted Average | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.143
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Unobservable Inputs	0.024
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	us-gaap:MeasurementInputDefaultRateMember
Obligations of States, Municipalities, and Political Subdivisions | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.024
Single Issuer Trust Preferred
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Debt Instrument, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Instrument, Measurement Input [Extensible List]	us-gaap:MeasurementInputDefaultRateMember
Single Issuer Trust Preferred | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.049
Single Issuer Trust Preferred | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.054
Single Issuer Trust Preferred | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.059
Servicing Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Servicing Asset, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Servicing Assets | Minimum | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.021
Servicing Assets | Maximum | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.177
Servicing Assets | Weighted Average | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.119

Fair Value Measurement - Summ_4

Fair Value Measurement - Summary of Assets Measured at Fair Value on Non-recurring Basis, Excluding Acquired Impaired Loans (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Commercial Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	$ 15,951	$ 9,792
Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	2,026	2,076
Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	18,262	17,397
Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	4,799	5,314
Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	13,596	14,489
Level 3 | Commercial Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	15,951	9,792
Level 3 | Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	2,026	2,076
Level 3 | Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	18,262	17,397
Level 3 | Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	4,799	5,314
Level 3 | Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	$ 13,596	$ 14,489

Fair Value Measurement - Summ_5

Fair Value Measurement - Summary of Estimated Fair Values of Financial Instruments and Levels Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands		Mar. 31, 2019	Dec. 31, 2018
Financial assets
Cash and due from banks		$ 50,026	$ 30,190
Interest bearing deposits with other banks		31,971	91,670
Securities held-to-maturity, fair value		4,431	97,739
Restricted stock, at cost		19,202	19,202
Loans held for sale		510	19,827
Loans and lease receivables, net (less impaired loans at fair value)		3,540,460	3,476,425
Accrued interest receivable		11,974	10,863
Financial liabilities
Federal Home Loan Bank advances		425,000	425,000
Securities sold under agreements to repurchase		34,369	34,166
Junior subordinated debentures issued to capital trusts, net		36,912	36,768
Level 1 | Carrying Amount
Financial assets
Cash and due from banks		50,026	30,190
Level 1 | Estimated Fair Value
Financial assets
Cash and due from banks		50,026	30,190
Level 2 | Carrying Amount
Financial assets
Interest bearing deposits with other banks		31,971	91,670
Securities held-to-maturity, fair value		4,425	99,266
Restricted stock, at cost		19,202	19,202
Financial liabilities
Non-interest-bearing deposits		1,163,255	1,192,873
Interest-bearing deposits		2,645,261	2,557,043
Accrued interest payable		4,390	3,484
Federal Home Loan Bank advances		425,000	425,000
Securities sold under agreements to repurchase		34,369	34,166
Level 2 | Estimated Fair Value
Financial assets
Interest bearing deposits with other banks		31,971	91,670
Securities held-to-maturity, fair value		4,431	97,739
Restricted stock, at cost		19,202	19,202
Financial liabilities
Non-interest-bearing deposits		1,163,255	1,192,873
Interest-bearing deposits		1,268,458	2,554,329
Accrued interest payable		4,390	3,484
Federal Home Loan Bank advances		425,000	425,000
Securities sold under agreements to repurchase		34,369	34,166
Level 3 | Carrying Amount
Financial assets
Loans held for sale		510	19,827
Loans and lease receivables, net (less impaired loans at fair value)	[1]	3,496,662	3,447,160
Accrued interest receivable		11,974	10,863
Financial liabilities
Junior subordinated debentures issued to capital trusts, net		36,912	36,768
Level 3 | Estimated Fair Value
Financial assets
Loans held for sale		563	21,654
Loans and lease receivables, net (less impaired loans at fair value)	[1]	3,401,501	3,407,652
Accrued interest receivable		11,974	10,863
Financial liabilities
Junior subordinated debentures issued to capital trusts, net		$ 42,292	$ 42,351
[1]	In accordance with the prospective adoption of ASU 2016-01, the fair value of loans and lease receivables, net (less impaired loans at fair value) as of March 31, 2019 was measured using an exit price notion. The fair value as of December 31, 2018 was measured using an entry price notion.

Derivative Instruments and He_3

Derivative Instruments and Hedge Activities - Summary of Derivative Financial Instruments and Classification on Consolidated Statements of Financial Condition (Details) - USD ($)	Mar. 31, 2019	Dec. 31, 2018
Derivatives Fair Value [Line Items]
Notional Amount	$ 579,297,000	$ 548,969,000
Other Assets	9,788,000	10,740,000
Other Liabilities	5,984,000	4,243,000
Cash Flow Hedges
Derivatives Fair Value [Line Items]
Notional Amount	250,000,000
Other Assets	4,160,000
Other Interest Rate Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	324,793,000
Other Assets	5,628,000
Other Liabilities	5,976,000
Derivatives Designated as Hedging Instruments | Interest Rate Swaps | Cash Flow Hedges
Derivatives Fair Value [Line Items]
Notional Amount	250,000,000	250,000,000
Other Assets	4,160,000	6,699,000
Derivatives Not Designated As Hedging Instruments | Other Credit Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	4,504,000	4,424,000
Other Liabilities	8,000	6,000
Derivatives Not Designated As Hedging Instruments | Other Interest Rate Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	324,793,000	294,545,000
Other Assets	5,628,000	4,041,000
Other Liabilities	$ 5,976,000	$ 4,237,000

Derivative Instruments and He_4

Derivative Instruments and Hedge Activities - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Derivative [Line Items]
Derivative notional amount	$ 579,297,000		$ 548,969,000
Unrealized gain (loss) to be reclassified as an decrease to interest expense during the next twelve months	2,100,000
Credit valuation adjustment increase (decrease) to non-interest income	(151,000)	$ 27,000
Cash Flow Hedges
Derivative [Line Items]
Derivative notional amount	250,000,000
Interest Rate Swaps | Interest Expense
Derivative [Line Items]
Decrease in FHLB expense	(705,000)	(61,000)
Other Interest Rate Derivatives
Derivative [Line Items]
Derivative notional amount	$ 324,793,000
Derivative maturity date, start year	Apr. 30, 2020
Derivative maturity date, end year	Jan. 31, 2030
Derivative instruments transaction fees	$ 325,000	0
Other Credit Derivatives
Derivative [Line Items]
Derivative notional amount	4,500,000	4,400,000
Derivative instruments transaction fees	0	26,000
Credit valuation adjustment increase (decrease) to non-interest income	(1,000)	$ (3,000)
Derivatives Designated as Hedging Instruments | Interest Rate Swaps | Cash Flow Hedges
Derivative [Line Items]
Derivative notional amount	250,000,000		250,000,000
Federal Home Loan Bank Advances | Derivatives Designated as Hedging Instruments | Interest Rate Swaps | Cash Flow Hedges
Derivative [Line Items]
Derivative notional amount	$ 250,000,000		$ 250,000,000

Derivative Instruments and He_5

Derivative Instruments and Hedge Activities - Summary of Cash Flow Hedges (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Amount	$ 579,297,000	$ 548,969,000
Derivative assets fair value	9,788,000	10,740,000
Derivative liabilities fair value	5,984,000	$ 4,243,000
Cash Flow Hedges
Derivative [Line Items]
Notional Amount	250,000,000
Derivative assets fair value	$ 4,160,000
Weighted average pay rates	1.67%
Weighted average receive rates	2.82%
Weighted average maturity	2 years 10 months 24 days

Derivative Instruments and He_6

Derivative Instruments and Hedge Activities - Summary of Net Gains (Losses) Recorded in Accumulated Other Comprehensive Income (Loss) and Consolidated Statements of Operations Relating to Cash Flow Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI	$ (1,817)	$ 4,070
Interest Rate Swaps
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI	(1,817)	4,070
Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense	$ 705	$ 61

Derivative Instruments and He_7

Derivative Instruments and Hedge Activities - Summary of Other Interest Rate Derivatives (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Amount	$ 579,297,000	$ 548,969,000
Derivative assets fair value	9,788,000	10,740,000
Derivative liabilities fair value	5,984,000	$ 4,243,000
Other Interest Rate Derivatives
Derivative [Line Items]
Notional Amount	324,793,000
Derivative assets fair value	5,628,000
Derivative liabilities fair value	$ 5,976,000
Weighted average pay rates	4.82%
Weighted average receive rates	4.64%
Weighted average maturity	5 years 10 months 24 days

Derivative Instruments and He_8

Derivative Instruments and Hedge Activities - Summary of Company's Interest Rate Derivative and Offsetting Positions (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Gross amounts recognized	$ 9,788	$ 10,740
Net amount presented in the Consolidated Statements of Financial Condition	9,788	10,740
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(3,852)	(2,823)
Collateral posted	(5,433)	(7,917)
Net credit exposure	503
Gross amounts recognized	5,984	4,243
Net amount presented in the Consolidated Statements of Financial Condition	5,984	4,243
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(3,852)	(2,823)
Collateral posted	(2,265)	(1,317)
Net credit exposure	$ (133)	$ 103

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($)

Apr. 30, 2019

Oct. 03, 2017

Jul. 06, 2017

Apr. 30, 2019

Apr. 30, 2018

Oct. 31, 2014

Mar. 31, 2019

Mar. 31, 2018

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Jun. 30, 2017

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Common stock, voting par value

$ 0.01

$ 0.01

Proceeds from the exercise of stock options

$ 636,000

$ 1,005,000

Income tax benefit

9,000

64,000

Oak Park River Forest

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Consideration paid in cash

$ 4,200,000

Business combination conversion of outstanding options

35,870

Oak Park River Forest | Subsequent Event

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Consideration paid in cash

$ 33,375

Restricted Shares

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Income tax benefit

$ 98,000

$ 31,000

Performance Options Grants

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Options vested

414,894

Common Stock

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of options exercised

50,662

86,750

Omnibus Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of common stock reserved and available for issuance

1,550,000

Number of common shares available for future grants

1,359,045

Omnibus Plan | Restricted Shares

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

4 years

Restricted shares vested

6,134

2,975

Fair value of restricted shares, vested

$ 102,000

$ 62,000

Fair value of unvested restricted stock awards

$ 3,400,000

Omnibus Plan | Performance-based Restricted Shares

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of restricted voting common stock granted

11,165

Period for number of shares earned under retun on average assets

3 years

Minimum target precentage in assets of peer group consisting publicly-traded bank holding companies

50.00%

Maximum target precentage in assets of peer group consisting publicly-traded bank holding companies

200.00%

Omnibus Plan | Performance-based Restricted Shares | Subsequent Event

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of restricted voting common stock granted

20,975

Period for number of shares earned under retun on average assets

3 years

Omnibus Plan | Performance-based Restricted Shares | Threshold performance

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Percentage of target number of shares to be earned

25.00%

Omnibus Plan | Performance-based Restricted Shares | 50th Percentile Performance

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Percentage of target number of shares to be earned

100.00%

Omnibus Plan | Performance-based Restricted Shares | 75th Percentile Performance

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Percentage of target number of shares to be earned

125.00%

Omnibus Plan | Common Stock

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Issuance of common stock in connection with restricted stock awards, shares

58,900

11,898

Omnibus Plan | Common Stock | Restricted Shares

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of restricted voting common stock granted

131,157

Common stock, voting par value

$ 0.01

Omnibus Plan | Common Stock | Restricted Shares | Subsequent Event

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares of restricted voting common stock granted

127,115

Common stock, voting par value

$ 0.01

$ 0.01

Omnibus Plan | Common Stock | Restricted Shares | Each Anniversary of Grant Date Over Four Years

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

4 years

Shares vest on grant date

102,559

Omnibus Plan | Common Stock | Restricted Shares | Each Anniversary of Grant Date Over Four Years | Subsequent Event

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

4 years

Shares vest on grant date

84,482

Omnibus Plan | Common Stock | Restricted Shares | Each Anniversary of Grant Date Vest Over Three Years

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

3 years

Shares vest on grant date

15,165

Omnibus Plan | Common Stock | Restricted Shares | Each Anniversary of Grant Date Vest Over Three Years | Subsequent Event

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

3 years

Shares vest on grant date

20,975

Omnibus Plan | Common Stock | Restricted Shares | First Anniversary of Grant Date

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares vest on grant date

2,268

Omnibus Plan | Common Stock | Restricted Shares | First Anniversary of Grant Date | Subsequent Event

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Shares vest on grant date

683

MBG Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of options granted

0

Number of options exercised

0

BYB Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of common shares available for future grants

0

Number of options granted

0

212,400

1,634,568

Number of options exercised

10,000

148,748

Number of shares outstanding

1,588,872

1,598,872

Award contractual term

6 years 3 months 18 days

6 years 7 months 6 days

Options vested

0

Proceeds from the exercise of stock options

$ 163,000

$ 1,700,000

Income tax benefit

$ 9,000

$ 449,000

BYB Plan | Maximum

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of common shares available for future grants

2,476,122

BYB Plan | Time Options Grants

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award contractual term

10 years

BYB Plan | Time Options Grants | Maximum

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

5 years

BYB Plan | Time Options Grants | Minimum

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

1 year

BYB Plan | Performance Options Grants

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award contractual term

10 years

BYB Plan | Performance Options Grants | Maximum

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

5 years

BYB Plan | Performance Options Grants | Minimum

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Award vesting period

1 year

FEB Plan

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of options exercised

40,662

56,404

Number of shares outstanding

583,721

624,383

Award contractual term

4 years 10 months 24 days

5 years 2 months 12 days

Proceeds from the exercise of stock options

$ 473,000

$ 601,000

Income tax benefit

$ 88,000

$ 168,000

Conversion calculation percentage

472.50%

FEB Plan | Restricted Shares

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Number of shares outstanding

0

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Changes in Restricted Shares (Details) - Omnibus Plan - Restricted Shares - $ / shares	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, beginning balance	196,480
Number of shares, vested	(6,134)	(2,975)
Number of shares, forfeited	(8,500)
Number of shares, ending balance	181,846	196,480
Weighted average grant date fair value, beginning balance	$ 21.66
Weighted average grant date fair value, vested	20.69
Weighted average grant date fair value, forfeited	21.03
Weighted average grant date fair value, ending balance	$ 21.72	$ 21.66

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Stock Compensation Expense (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation - restricted stock	$ 33	$ 229
Income tax benefit	9	64
Unrecognized compensation expense	$ 113	$ 499
Weighted-average amortization period remaining	9 months 18 days	1 year 1 month 6 days
Restricted Shares
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation - restricted stock	$ 353	$ 112
Income tax benefit	98	31
Unrecognized compensation expense	$ 2,675	$ 1,114
Weighted-average amortization period remaining	2 years 8 months 12 days	2 years 7 months 6 days

Share-Based Compensation - Su_3

Share-Based Compensation - Summary Activity in shares Subjected to Options and Weighted Average Exercise Prices (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
BYB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Beginning balance	1,598,872
Number of Shares, Exercised	(10,000)	(148,748)
Number of Shares, Ending balance	1,588,872	1,598,872
Number of Shares, Exercisable	1,490,572
Weighted Average Exercise Price, Beginning balance	$ 11.84
Weighted Average Exercise Price, Exercised	16.25
Weighted Average Exercise Price, Ending balance	11.81	$ 11.84
Weighted Average Exercise Price, Exercisable	$ 11.52
Intrinsic Value, Beginning balance	$ 7,713
Intrinsic Value, Exercised	32
Intrinsic Value, Ending balance	10,601	$ 7,713
Intrinsic Value, Exercisable	$ 10,382
Weighted Average Remaining Contractual Term (in Years)	6 years 3 months 18 days	6 years 7 months 6 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	6 years 3 months 18 days
Number of Shares, Granted			0	212,400	1,634,568
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Beginning balance	624,383
Number of Shares, Exercised	(40,662)	(56,404)
Number of Shares, Ending balance	583,721	624,383
Number of Shares, Exercisable	583,721
Weighted Average Exercise Price, Beginning balance	$ 11.31
Weighted Average Exercise Price, Exercised	11.63
Weighted Average Exercise Price, Ending balance	11.29	$ 11.31
Weighted Average Exercise Price, Exercisable	$ 11.29
Intrinsic Value, Beginning balance	$ 3,339
Intrinsic Value, Exercised	316
Intrinsic Value, Ending balance	4,197	$ 3,339
Intrinsic Value, Exercisable	$ 4,197
Weighted Average Remaining Contractual Term (in Years)	4 years 10 months 24 days	5 years 2 months 12 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	4 years 10 months 24 days

Earnings per Share - Additional

Earnings per Share - Additional Information (Details) - shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share Basic [Line Items]
Shares outstanding	36,169,477	29,291,179
Stock Options
Earnings Per Share Basic [Line Items]
Shares outstanding	2,172,593	1,696,270
Restricted Stock Award
Earnings Per Share Basic [Line Items]
Shares outstanding	181,846	70,798

Earnings per Share - Schedule o

Earnings per Share - Schedule of Calculation of Basic and Diluted Earnings per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Earnings Per Share [Abstract]
Net income	$ 12,597	$ 6,768
Dividends on preferred shares	196	193
Net income available to common stockholders	$ 12,401	$ 6,575
Weighted-average common stock outstanding:
Weighted-average common stock outstanding (basic)	36,169,477	29,291,179
Incremental shares	707,097	622,454
Weighted-average common stock outstanding (dilutive)	36,876,574	29,913,633
Basic earnings per common share	$ 0.34	$ 0.22
Diluted earnings per common share	$ 0.34	$ 0.22

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Preferred and Common Stock (Details) - $ / shares	Mar. 31, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Common stock, voting par value	$ 0.01	$ 0.01
Common stock, voting shares authorized	150,000,000	150,000,000
Common stock, voting shares issued	36,398,144	36,343,239
Common stock, voting shares outstanding	36,398,144	36,343,239
Series B 7.5% Fixed to Floating Non-Cumulative Perpetual Preferred Stock
Class Of Stock [Line Items]
Par value	$ 0.01	$ 0.01
Shares authorized	50,000	50,000
Shares issued	10,438	10,438
Shares outstanding	10,438	10,438

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Preferred and Common Stock (Parenthetical) (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Series B 7.5% Fixed to Floating Non-Cumulative Perpetual Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage	7.50%	7.50%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2016
Class Of Stock [Line Items]
Dividends declared and paid	$ 196,000	$ 193,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage			7.50%
Preferred stock, liquidation preference per share			$ 1,000
Preferred stock fixed dividend close date			Dec. 30, 2021
Preferred stock redemption price per share			$ 1,000
Dividends declared and paid	$ 196,000	$ 193,000
Series B Preferred Stock | Three-month LIBOR
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage			5.41%

Consolidated Statements of Ch_4

Consolidated Statements of Change in Accumulated Other Comprehensive Income (Loss) - Schedule of Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 650,672	$ 458,578
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)		(763)
Adoption of ASU 2016-01	(1,440)
Other comprehensive income (loss), net of tax	4,519	(3,564)
Ending balance	668,749	462,936
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	4,763	2,913
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)		687
Other comprehensive income (loss), net of tax	(1,820)	2,893
Ending balance	2,943	6,493
Unrealized Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(14,261)	(8,000)
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)		(1,450)
Adoption of ASU 2016-01	(1,440)
Other comprehensive income (loss), net of tax	6,339	(6,457)
Ending balance	(9,362)	(15,907)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(9,498)	(5,087)
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)		(763)
Other comprehensive income (loss), net of tax	4,519	(3,564)
Ending balance	$ (6,419)	$ (9,414)