Byline Bancorp (BY) 10-Q 13 Aug 18 2018 Q2 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	6 Months Ended
	Jun. 30, 2018	Aug. 10, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Jun. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q2
Trading Symbol	BY
Entity Registrant Name	Byline Bancorp, Inc.
Entity Central Index Key	1,702,750
Current Fiscal Year End Date	--12-31
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		36,218,955

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 25,299	$ 19,404
Interest bearing deposits with other banks	127,417	38,945
Cash and cash equivalents	152,716	58,349
Securities available-for-sale, at fair value	757,825	583,236
Securities held-to-maturity, at amortized cost (fair value June 30, 2018—$104,411, December 31, 2017—$117,277)	106,613	117,163
Restricted stock, at cost	18,977	16,343
Loans held for sale	5,822	5,212
Loans and leases:
Loans and leases	3,348,692	2,277,492
Allowance for loan and lease losses	(19,687)	(16,706)
Net loans and leases	3,329,005	2,260,786
Servicing assets, at fair value	21,587	21,400
Accrued interest receivable	10,670	7,670
Premises and equipment, net	107,300	95,224
Assets held for sale	11,428	9,779
Other real estate owned, net	6,402	10,626
Goodwill	127,536	54,562
Other intangible assets, net	37,139	16,756
Bank-owned life insurance	5,886	5,718
Deferred tax assets, net	48,936	47,376
Due from counterparty	25,569	39,824
Other assets	31,869	16,106
Total assets	4,805,280	3,366,130
LIABILITIES
Non-interest bearing demand deposits	1,193,057	760,887
Interest bearing deposits:
NOW, savings accounts, and money market accounts	1,391,568	973,685
Time deposits	1,060,252	708,757
Total deposits	3,644,877	2,443,329
Accrued interest payable	2,562	1,306
Federal Home Loan Bank advances	420,000	361,506
Securities sold under agreements to repurchase	24,653	31,187
Junior subordinated debentures issued to capital trusts, net	36,452	27,647
Accrued expenses and other liabilities	60,330	42,577
Total liabilities	4,188,874	2,907,552
STOCKHOLDERS’ EQUITY
Preferred stock	10,438	10,438
Common stock, voting $0.01 par value at June 30, 2018 and December 31, 2017; 150,000,000 shares authorized at June 30, 2018 and December 31, 2017; 36,218,955 shares issued and outstanding at June 30, 2018 and 29,317,298 issued and outstanding at December 31, 2017	360	292
Additional paid-in capital	544,686	391,586
Retained earnings	71,257	61,349
Accumulated other comprehensive loss, net of tax	(10,335)	(5,087)
Total stockholders’ equity	616,406	458,578
Total liabilities and stockholders’ equity	$ 4,805,280	$ 3,366,130

CONSOLIDATED STATEMENTS OF FIN3

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Securities held-to-maturity, fair value	$ 104,411	$ 117,277
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	36,218,955	29,317,298
Common stock, voting shares outstanding	36,218,955	29,317,298

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
INTEREST AND DIVIDEND INCOME
Interest and fees on loans and leases	$ 39,627,000	$ 29,181,000	$ 73,281,000	$ 57,577,000
Interest on taxable securities	4,572,000	3,703,000	8,627,000	7,493,000
Interest on tax-exempt securities	229,000	151,000	403,000	284,000
Other interest and dividend income	413,000	280,000	672,000	449,000
Total interest and dividend income	44,841,000	33,315,000	82,983,000	65,803,000
INTEREST EXPENSE
Deposits	3,745,000	1,923,000	6,243,000	3,406,000
Federal Home Loan Bank advances	1,360,000	772,000	2,718,000	1,432,000
Subordinated debentures and other borrowings	680,000	809,000	1,271,000	1,616,000
Total interest expense	5,785,000	3,504,000	10,232,000	6,454,000
Net interest income	39,056,000	29,811,000	72,751,000	59,349,000
PROVISION FOR LOAN AND LEASE LOSSES	3,956,000	3,515,000	9,071,000	5,406,000
Net interest income after provision for loan and lease losses	35,100,000	26,296,000	63,680,000	53,943,000
NON-INTEREST INCOME
Fees and service charges on deposits	1,456,000	1,348,000	2,768,000	2,567,000
Net servicing fees	459,000	1,076,000	1,022,000	1,995,000
ATM and interchange fees	1,141,000	1,499,000	2,359,000	2,847,000
Net gains on sales of securities available-for-sale	4,000		4,000	8,000
Net gains on sales of loans	9,723,000	8,445,000	17,199,000	16,527,000
Wealth management and trust income	192,000		192,000
Other non-interest income	1,527,000	825,000	2,386,000	1,557,000
Total non-interest income	14,502,000	13,193,000	25,930,000	25,501,000
NON-INTEREST EXPENSE
Salaries and employee benefits	19,244,000	17,226,000	37,522,000	33,828,000
Occupancy expense, net	4,499,000	3,485,000	8,254,000	7,224,000
Equipment expense	558,000	616,000	1,161,000	1,179,000
Loan and lease related expenses	1,471,000	801,000	2,871,000	1,678,000
Legal, audit and other professional fees	4,418,000	1,090,000	6,269,000	2,761,000
Data processing	10,371,000	2,447,000	12,672,000	4,856,000
Net loss (gain) recognized on other real estate owned and other related expenses	472,000	141,000	471,000	(429,000)
Regulatory assessments	366,000	384,000	607,000	568,000
Other intangible assets amortization expense	1,130,000	769,000	1,897,000	1,538,000
Advertising and promotions	347,000	318,000	596,000	607,000
Telecommunications	466,000	396,000	884,000	814,000
Other non-interest expense	2,428,000	1,576,000	4,485,000	3,476,000
Total non-interest expense	45,770,000	29,249,000	77,689,000	58,100,000
INCOME BEFORE PROVISION FOR INCOME TAXES	3,832,000	10,240,000	11,921,000	21,344,000
PROVISION FOR INCOME TAXES	1,064,000	4,094,000	2,385,000	8,638,000
NET INCOME	2,768,000	6,146,000	9,536,000	12,706,000
Dividends on preferred shares	198,000	10,697,000	391,000	10,886,000
INCOME AVAILABLE (LOSS ATTRIBUTABLE) TO COMMON STOCKHOLDERS	$ 2,570,000	$ (4,551,000)	$ 9,145,000	$ 1,820,000
EARNINGS (LOSS) PER COMMON SHARE
Basic	$ 0.08	$ (0.18)	$ 0.30	$ 0.07
Diluted	$ 0.08	$ (0.18)	$ 0.29	$ 0.07

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 2,768	$ 6,146	$ 9,536	$ 12,706
Securities available-for-sale
Unrealized holding gains (losses) arising during the period	(2,556)	2,427	(11,408)	3,447
Reclassification adjustments for net gains included in net income	(4)		(4)	(8)
Tax effect	782	(1,264)	3,177	(1,890)
Net of tax	(1,778)	1,163	(8,235)	1,549
Cash flow hedges
Unrealized holding gains (losses) arising during the period	1,562	(1,343)	5,632	(1,425)
Reclassification adjustments for net gains (losses) included in net income	(374)	214	(435)	267
Tax effect	(331)	454	(1,447)	465
Net of tax	857	(675)	3,750	(693)
Total other comprehensive income (loss)	(921)	488	(4,485)	856
Comprehensive income	$ 1,847	$ 6,634	$ 5,051	$ 13,562

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, 2016	$ 382,658	$ 25,441		$ 313,552	$ 50,933	$ (7,268)
Beginning balance, shares at Dec. 31, 2016		25,441	24,616,706
Net income	12,706				12,706
Other comprehensive income (loss), net of tax	856					856
Issuance of common stock in connection with merger			$ 246	(246)
Repurchase of preferred stock	(15,003)	$ (15,003)
Repurchase of preferred stock, shares		(15,003)
Issuance of common stock, net of issuance costs	76,829		$ 46	76,783
Issuance of common stock, net of issuance cost, shares			4,630,194
Cash dividends declared on preferred stock	(10,886)				(10,886)
Share-based compensation expense	571			571
Ending balance at Jun. 30, 2017	447,731	$ 10,438	$ 292	390,660	52,753	(6,412)
Ending balance, shares at Jun. 30, 2017		10,438	29,246,900
Beginning balance at Dec. 31, 2016	382,658	$ 25,441		313,552	50,933	(7,268)
Beginning balance, shares at Dec. 31, 2016		25,441	24,616,706
Ending balance at Dec. 31, 2017	458,578	$ 10,438	$ 292	391,586	61,349	(5,087)
Ending balance, shares at Dec. 31, 2017		10,438	29,317,298
Net income	9,536				9,536
Other comprehensive income (loss), net of tax	(4,485)					(4,485)
Issuance of common stock upon exercise of stock options	1,135		$ 1	1,134
Issuance of common stock upon exercise of stock options, shares			94,750
Issuance of common stock and stock options due to business combination, net of issuance costs	151,275		$ 67	151,208
Issuance of common stock and stock options due to business combination, net of issuance costs, shares			6,682,850
Issuance of common stock in connection with restricted stock awards, shares			126,157
Forfeiture of restricted stock awards, shares			(2,100)
Reclassification of certain income tax effects from accumulated other comprehensive income	(763)				763	(763)
Cash dividends declared on preferred stock	(391)				(391)
Share-based compensation expense	758			758
Ending balance at Jun. 30, 2018	$ 616,406	$ 10,438	$ 360	$ 544,686	$ 71,257	$ (10,335)
Ending balance, shares at Jun. 30, 2018		10,438	36,218,955

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 9,536	$ 12,706
Adjustments to reconcile net income to net cash from operating activities:
PROVISION FOR LOAN AND LEASE LOSSES	9,071	5,406
Impairment loss on assets held for sale	117
Depreciation and amortization of premises and equipment	2,608	2,608
Net amortization of securities	1,876	2,361
Net gains on sales of securities available-for-sale	(4)	(8)
Net gains on sales of assets held for sale	(162)	(162)
Net gains on sales of loans	(17,199)	(16,527)
Net proceeds from mortgage loans sold		151
Originations of government guaranteed loans	(175,120)	(134,333)
Proceeds from government guaranteed loans sold	204,807	150,688
Accretion of premiums and discounts on acquired loans, net	(13,660)	(12,421)
Net change in servicing assets	(187)	(333)
Net valuation adjustments on other real estate owned	60	320
Net losses (gains) on sales of other real estate owned	109	(1,464)
Other intangible assets amortization expense	1,897	1,538
Amortization of time deposit premium	(84)	(680)
Amortization of Federal Home Loan Bank advances premium	(19)	(104)
Accretion of junior subordinated debentures discount	308	383
Share-based compensation expense	758	571
Deferred tax provision	2,225	7,547
Increase in cash surrender value of bank owned life insurance	(168)	(172)
Net gain on death benefit of bank owned life insurance		(313)
Changes in assets and liabilities:
Accrued interest receivable	(77)	(107)
Other assets	(3,803)	1,165
Accrued interest payable	686	(865)
Accrued expenses and other liabilities	22,530	10,895
Net cash provided by operating activities	46,105	28,850
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of securities available-for-sale	(96,086)	(17,499)
Proceeds from maturities and calls of securities available-for-sale	6,630	1,182
Proceeds from paydowns of securities available-for-sale	29,462	34,562
Proceeds from sales of securities available-for-sale	544	8
Proceeds from paydowns of securities held-to-maturity	9,601	10,112
Purchases of Federal Home Loan Bank stock	(13,998)	(5,760)
Federal Home Loan Bank stock repurchases	12,724	8,775
Proceeds from other loans sold		9,984
Net change in loans and leases	(158,258)	(13,823)
Purchases of premises and equipment	(537)	(1,604)
Proceeds from sales of assets held for sale	1,041	2,752
Proceeds from sales of other real estate owned	4,678	7,520
Net cash received in acquisition of business	20,374
Net cash (used in) provided by investing activities	(183,825)	36,209
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	179,364	50,884
Proceeds from Federal Home Loan Bank advances	2,941,900	1,290,000
Repayments of Federal Home Loan Bank advances	(2,883,387)	(1,384,000)
Repayments of line of credit		(4,500)
Net (decrease) increase in securities sold under agreements to repurchase	(6,534)	15,180
Dividends paid on preferred stock	(391)	(385)
Proceeds from issuance of common stock upon exercise of stock options	1,135
Proceeds from issuance of preferred stock		1,050
Net cash provided by (used in) financing activities	232,087	(31,771)
NET INCREASE IN CASH AND CASH EQUIVALENTS	94,367	33,288
CASH AND CASH EQUIVALENTS, beginning of period	58,349	46,533
CASH AND CASH EQUIVALENTS, end of period	152,716	79,821
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	9,081	7,720
Cash payments during the period for taxes	2,752	1,100
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in fair value of available-for-sale securities, net of tax	(8,235)	1,549
Change in fair value of cash flow hedges, net of tax	3,750	(693)
Delayed payments of mortgage-backed securities	621	834
Transfers of loans to loans held for sale		10,061
Transfers of loans to other real estate owned	1,067	2,490
Internally financed sale of other real estate owned	444
Transfers of land and premises to assets held for sale	2,531	1,508
Transfers of premises and equipment to other assets	2	671
Transfers of other assets to assets held for sale	16
Due from carrier for payment of life insurance death benefit		1,399
Due from counterparty	5,582	19,257
Due from broker for issuance of common stock, net of underwriters' discount		82,699
Due to broker	10,029	10,059
Total assets acquired from acquisition	1,142,766
Total liabilities assumed from acquisition	1,036,609
Common stock and stock options issued due to acquisition of business	$ 152,127
Series A
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Due to preferred stockholders for repurchase of Series A preferred stock		$ (25,504)

Basis of Presentation

Basis of Presentation	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	Note 1—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 June 30, 2018 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, 2017, 2016, and 2015. 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. No 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. During the three months ended March 31, 2018, we revised our previously issued 2017 consolidated financial statements to properly record a deferred tax liability associated with the bad debt recapture assumed from the acquisition of Ridgestone Financial Services, Inc. (“Ridgestone”) and its subsidiaries on October 14, 2016. The acquisition of Ridgestone was accounted for using the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations (“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 2017. We evaluated the effect of the error to our previously issued consolidated financial statements in accordance with Securities and Exchange Commission Staff Accounting Bulletin No. 99 and No. 108, and, based upon quantitative and qualitative factors, determined that the error was not material to our previously issued consolidated financial statements. Accordingly, we have reflected the change in 2017 and revised our Consolidated Statements of Financial Condition disclosed herein. Consolidated financial statements for periods not presented herein will be revised, as applicable, as they are included in future filings. All financial information presented in the accompanying notes to these consolidated financial statements was revised to reflect the change. The change did not affect net income or stockholders’ equity for the periods impacted. The following table presents the effect of the aforementioned revisions to our Consolidated Statements of Financial Condition as of December 31, 2017: December 31, 2017 (dollars in thousands) As Reported Adjustment As Revised Goodwill $ 51,975 $ 2,587 $ 54,562 Deferred tax assets, net 49,963 (2,587 ) 47,376 Total assets 3,366,130 — 3,366,130

Recently Issued Accounting Pron

Recently Issued Accounting Pronouncements	6 Months Ended
	Jun. 30, 2018
Accounting Changes And Error Corrections [Abstract]
Recently Issued Accounting Pronouncements	Note 2—Recently Issued Accounting Pronouncements 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. 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 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. Under the terms of ASU No. 2015-14 the standard is effective for interim and annual periods beginning after December 15, 2017. Early application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. For financial reporting purposes, the standard allows for either full retrospective adoption, meaning the standard is applied to all of the periods presented, or modified retrospective adoption, meaning the standard is applied only to the most current period presented in the financial statements with the cumulative effect of initially applying the standard recognized at the date of initial application. The Company is currently evaluating the provisions of ASU No. 2014-09 to determine the potential impact the standard will have on the Company’s Consolidated Financial Statements. As a financial institution, the Company’s largest component of revenue, interest income, is excluded from the scope of this ASU. The Company is currently evaluating which, if any, of its sources of non-interest income will be impacted by this ASU. Assuming the Company remains an emerging growth company, the Company expects to adopt this new guidance on January 1, 2019, with a cumulative effect adjustment to opening retained earnings, if such adjustment is deemed to be significant. In April 2016, FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing . The amendments in this ASU do not change the core principle of the guidance in Topic 606. Rather, 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. The amendments in this ASU affect the guidance in ASU 2014-09, discussed above, which is not yet effective. The effective date and transition requirements for the amendments in this ASU are the same as the effective date and transition requirements in Topic 606, Revenues from Contracts with Customers . The Company is evaluating the provisions of this ASU in conjunction with ASU No. 2014-09 to determine the potential impact Topic 606 and its amendments will have on the Company’s Consolidated Financial Statements. In May 2016, FASB issued ASU No. 2016-12, Narrow-Scope Improvements and Practical Expedients Revenue from Contracts with Customers In November 2017, FASB issued ASU No. 2017-14, amending ASC Topic 606, Revenue from Contracts with Customers Revenue from Contracts with Customers Recognition and Measurement of Financial Assets and Financial Liabilities Recognition and Measurement of Financial Assets and Financial Liabilities In March 2018, FASB issued ASU No. 2018-03, Recognition and Measurement of Financial Assets and Financial Liabilities 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 lease contracts where the Company is a lessee. 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 with early adoption permitted. The Company is evaluating the new guidance and its impact on the Company’s Consolidated Statements of Operations and Consolidated Statements of Financial Condition. 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) or 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. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company is evaluating the new guidance and its impact on the Company’s Consolidated Statements of Operations and Consolidated Statements of Financial Condition. In June 2018, the FASB issued ASU 2018-07, Improvements to Nonemployee Share-based Payment Accounting Revenue from Contracts with Customers 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. 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. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company is currently evaluating the provisions of ASU No. 2016-15 to determine the potential impact the new standard will have on the Company’s Consolidated Financial Statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (230), Restricted Cash Income Taxes (Topic 740) In October 2016, the FASB issued ASU No. 2016-16, Income Taxes, Intra-Entity Transfers of Assets Other Than Inventory . The ASU was issued to improve the accounting for income tax consequences of intra-entity transfers of assets other than inventory. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party; this update clarifies that an entity should recognize the income tax consequences of an intra-entity transfer of assets other than inventory when the transfer occurs. The amendment is effective for annual reporting periods beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption of the update is permitted. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company does not expect this ASU to have a material impact on the Company’s Consolidated Financial Statements. 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. Early adoption is permitted. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company does not expect a material impact of this ASU on the Company’s Consolidated Financial Statements. Intangibles—Goodwill and Other (Topic 350) In January 2017, FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment . The amendments in this ASU are intended to reduce the cost and complexity of the goodwill impairment test by eliminating step two from the impairment test. The amendments modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. Under the amendments in this ASU, an entity will perform its annual, or interim, goodwill impairment test by comparing the fair value of the reporting unit with its carrying amount. An impairment charge should be recognized for the amount which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amendments in this ASU are effective for the Company’s annual or any interim goodwill impairment test in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company early adopted these amendments in 2017, which did not have a material impact on the Company’s Consolidated Financial Statements. Other Income (Subtopic 610-20) In February 2017, the FASB issued ASU No. 2017-05, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets . This ASU will clarify the scope of Subtopic 610-20 and add guidance for partial sales of nonfinancial assets. The amendments should be applied either on retrospectively to each period presented or with a modified retrospective approach. The amendment is effective for annual periods beginning after December 15, 2018, and interim periods within annual periods beginning after December 15, 2019. The Company is currently evaluating the provisions of ASU No. 2017-05 to determine the potential impact the new standard will have on the Company’s Consolidated Financial Statements. 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. Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) In July 2017, FASB issued ASU No. 2017-11, (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception . The ASU simplifies the accounting for certain financial instruments with down round features, a provision in an equity-linked financial instrument (or embedded feature) that provides a downward adjustment of the current exercise price based on the price of future equity offerings. Down round features are common in warrants, convertible preferred shares, and convertible debt instruments. The ASU requires companies to disregard the down round feature when assessing whether the instrument is indexed to its own stock, for purposes of determining liability or equity classification. Companies that provide earnings per share (EPS) data will adjust their basic EPS calculation for the effect of the feature when triggered (i.e., when the exercise price of the related equity-linked financial instrument is adjusted downward because of the down round feature) and will also recognize the effect of the trigger within equity. 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. 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. 2017‑11 to determine the potential impact the new standard will have 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 to retained earnings. Financial Services—Depository and Lending (Topic 942) In May 2018, FASB issued ASU No. 2018-06, Codification Improvements to Topic 942, Depository and Lending — Income Taxes . The amendments in this ASU supersede the guidance within Subtopic 942-741 that has been rescinded by the OCC and no longer relevant. A cross-reference between Subtopic 740-30, Income Taxes—Other Considerations or Special Areas, and Subtopic 942-740 is being added to the remaining guidance in Subtopic 740-30 to improve the usefulness of the codification. The amendments in this Update are effective upon issuance, as no accounting requirements are affected. The amendments in this ASU do not have a material impact on the Company’s Consolidated Financial Statements.

Acquisition of a Business

Acquisition of a Business	6 Months Ended
	Jun. 30, 2018
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 $73.0 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. Merger-related expenses, including acquisition advisory expenses of $1.6 million and core system conversion expenses of $9.0 million related to the First Evanston acquisition, are reflected in non-interest expense on the Consolidated Statements of Operations for the six months ended June 30, 2018. 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. Fair values are preliminary and subject to refinement for up to one year after the closing date of the acquisition as additional information regarding the closing date fair values become available. The following table presents a summary of the preliminary estimates of 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 16,778 Other intangible assets 22,276 Deferred tax assets, net 2,055 Other assets 8,845 Total assets acquired 1,142,766 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 $ 106,157 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 $ 72,974 The following table presents the acquired non-impaired loans as of the acquisition date: Fair value $ 889,115 Gross contractual amounts receivable 1,055,502 Estimate of contractual cash flows not expected to be collected (1) 36,544 Estimate of contractual cash flows expected to be collected 1,018,958 (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 and six months ended June 30, 2018 and 2017, as if the acquisition had occurred on January 1, 2017. 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 security discount accretion, loan discount accretion, intangible assets amortization, deposit premium accretion, fixed assets amortization, and borrowing 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, 2017. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for loan and lease 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 For the Six Months Ended June 30, June 30, 2018 2017 2018 2017 Total revenues (net interest income and non-interest income) $ 61,775 $ 55,995 $ 119,828 $ 111,641 Net income $ 10,709 $ 9,075 $ 21,166 $ 19,073 Earnings (loss) per share—basic $ 0.29 $ (0.05 ) $ 0.58 $ 0.26 Earnings (loss) per share—diluted $ 0.28 $ (0.05 ) $ 0.56 $ 0.26 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 June 30, 2018. 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.

Securities

Securities	6 Months Ended
	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Securities	Note 4—Securities The following June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 44,683 $ 4 $ (264 ) $ 44,423 U.S. Government agencies 146,887 26 (1,904 ) 145,009 Obligations of states, municipalities, and political subdivisions 59,995 110 (812 ) 59,293 Residential mortgage-backed securities Agency 313,823 — (14,289 ) 299,534 Non-agency 63,519 — (1,556 ) 61,963 Commercial mortgage-backed securities Agency 76,332 72 (3,151 ) 73,253 Non-agency 31,612 — (1,508 ) 30,104 Corporate securities 37,707 227 (344 ) 37,590 Other securities 4,610 2,176 (130 ) 6,656 Total $ 779,168 $ 2,615 $ (23,958 ) $ 757,825 June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,934 $ 28 $ (373 ) $ 23,589 Residential mortgage-backed securities Agency 45,422 — (843 ) 44,579 Non-agency 37,257 — (1,014 ) 36,243 Total $ 106,613 $ 28 $ (2,230 ) $ 104,411 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 14,999 $ — $ (136 ) $ 14,863 U.S. Government agencies 54,248 — (1,290 ) 52,958 Obligations of states, municipalities, and political subdivisions 33,405 100 (335 ) 33,170 Residential mortgage-backed securities Agency 315,103 — (7,646 ) 307,457 Non-agency 39,485 104 (75 ) 39,514 Commercial mortgage-backed securities Agency 70,964 45 (1,966 ) 69,043 Non-agency 31,763 — (792 ) 30,971 Corporate securities 29,573 507 (104 ) 29,976 Other securities 3,627 1,730 (73 ) 5,284 Total $ 593,167 $ 2,486 $ (12,417 ) $ 583,236 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 24,030 $ 197 $ (82 ) $ 24,145 Residential mortgage-backed securities Agency 53,731 79 (203 ) 53,607 Non-agency 39,402 174 (51 ) 39,525 Total $ 117,163 $ 450 $ (336 ) $ 117,277 The Company did not classify securities as trading during the six months ended June 30, 2018 or during 2017. 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 June 30, 2018 and December 31, 2017 are summarized as follows: Less than 12 Months 12 Months or Longer Total June 30, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 18 $ 24,695 $ (76 ) $ 9,813 $ (188 ) $ 34,508 $ (264 ) U.S. Government agencies 36 62,216 (92 ) 51,471 (1,812 ) 113,687 (1,904 ) Obligations of states, municipalities and political subdivisions 40 24,271 (564 ) 4,396 (248 ) 28,667 (812 ) Residential mortgage-backed securities Agency 44 30,404 (604 ) 269,131 (13,685 ) 299,535 (14,289 ) Non-agency 7 57,749 (1,350 ) 4,213 (206 ) 61,962 (1,556 ) Commercial mortgage-backed securities Agency 8 7,228 (46 ) 54,473 (3,105 ) 61,701 (3,151 ) Non-agency 5 — — 30,104 (1,508 ) 30,104 (1,508 ) Corporate securities 11 16,946 (133 ) 4,744 (211 ) 21,690 (344 ) Other securities 1 — — 2,844 (130 ) 2,844 (130 ) Total 170 $ 223,509 $ (2,865 ) $ 431,189 $ (21,093 ) $ 654,698 $ (23,958 ) Less than 12 Months 12 Months or Longer Total June 30, 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 27 $ 18,166 $ (327 ) $ 1,538 $ (46 ) $ 19,704 $ (373 ) Residential mortgage-backed securities Agency 20 37,755 (558 ) 6,824 (285 ) 44,579 (843 ) Non-agency 7 32,173 (847 ) 4,070 (167 ) 36,243 (1,014 ) Total 54 $ 88,094 $ (1,732 ) $ 12,432 $ (498 ) $ 100,526 $ (2,230 ) Less than 12 Months 12 Months or Longer Total December 31, 2017 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 5 $ 4,998 $ (2 ) $ 9,865 $ (134 ) $ 14,863 $ (136 ) U.S. Government agencies 9 992 (7 ) 51,966 (1,283 ) 52,958 (1,290 ) Obligations of states, municipalities and political subdivisions 29 16,059 (137 ) 4,453 (198 ) 20,512 (335 ) Residential mortgage-backed securities Agency 41 15,441 (181 ) 292,016 (7,465 ) 307,457 (7,646 ) Non-agency 1 — — 4,565 (75 ) 4,565 (75 ) Commercial mortgage-backed securities Agency 7 — — 57,442 (1,966 ) 57,442 (1,966 ) Non-agency 5 — — 30,971 (792 ) 30,971 (792 ) Corporate securities 3 2,406 (80 ) 2,489 (24 ) 4,895 (104 ) Other securities 1 — — 1,921 (73 ) 1,921 (73 ) Total 101 $ 39,896 $ (407 ) $ 455,688 $ (12,010 ) $ 495,584 $ (12,417 ) Less than 12 Months 12 Months or Longer Total December 31, 2017 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 12 $ 7,409 $ (38 ) $ 1,548 $ (44 ) $ 8,957 $ (82 ) Residential mortgage-backed securities Agency 13 24,344 (107 ) 7,935 (96 ) 32,279 (203 ) Non-agency 3 10,458 (10 ) 4,382 (41 ) 14,840 (51 ) Total 28 $ 42,211 $ (155 ) $ 13,865 $ (181 ) $ 56,076 $ (336 ) Certain o available-for-sale The proceeds three and six months ended June 30, 2018 For the Three Months Ended For the Six Months Ended June 30, June 30, 2018 2017 2018 2017 Proceeds $ 544 $ — $ 544 $ 8 Gross gains 4 — 4 8 Gross losses — — — — There were $4,000 gains reclassified from income income Securities pledged at June 30, 2018 and December 31, 2017 had carrying amounts of $221.4 million and $262.5 million, At June 30, 2018, the Amortized Cost Fair Value Available-for-sale Due in one year or less $ 40,479 $ 40,475 Due from one to five years 187,741 186,169 Due from five to ten years 49,553 48,404 Due after ten years 12,036 11,958 Mortgage-backed securities 485,286 464,854 Other securities with no defined maturity 4,073 5,965 Total $ 779,168 $ 757,825 Held-to-maturity Due from one to five years $ 4,060 $ 4,031 Due from five to ten years 11,646 11,442 Due after ten years 8,228 8,116 Mortgage-backed securities 82,679 80,822 Total $ 106,613 $ 104,411

Loan and Lease Receivables

Loan and Lease Receivables	6 Months Ended
	Jun. 30, 2018
Receivables [Abstract]
Loan and Lease Receivables	Note 5—Loan Outstanding loan and lease receivables as of the dates shown were categorized as follows: June 30, December 31, 2018 2017 Commercial real estate $ 1,235,158 $ 891,971 Residential real estate 699,482 577,123 Construction, land development, and other land 189,490 105,996 Commercial and industrial 1,026,371 522,254 Installment and other 12,758 4,182 Lease financing receivables 183,304 174,165 Total loans and leases 3,346,563 2,275,691 Net unamortized deferred fees and costs (1,442 ) (1,720 ) Initial direct costs 3,571 3,521 Allowance for loan and lease losses (19,687 ) (16,706 ) Net loans and leases $ 3,329,005 $ 2,260,786 June 30, December 31, 2018 2017 Lease financing receivables Net minimum lease payments $ 199,246 $ 188,986 Unguaranteed residual values 1,654 1,644 Unearned income (17,596 ) (16,465 ) Total lease financing receivables 183,304 174,165 Initial direct costs 3,571 3,521 Lease financial receivables before allowance for lease losses $ 186,875 $ 177,686 Total loans and leases consist of originated loans and leases, acquired impaired loans and acquired non-impaired loans and leases. At June 30, 2018 and December 31, 2017, total loans and leases included the guaranteed amount of U.S. Government guaranteed loans of $95.1 million and $77.0 million, respectively. At June 30, 2018 and December 31, 2017, installment and other loans included overdraft deposits of $1.3 million and $617,000, respectively, which were reclassified as loans. At June 30, 2018 and December 31, 2017, loans and loans held for sale pledged as security for borrowings were $1.4 billion and $516.9 million, respectively. The minimum Minimum Lease Payments 2018 $ 35,976 2019 64,945 2020 48,587 2021 30,122 2022 15,850 Thereafter 3,766 Total $ 199,246 Originated Topic Topic June 30, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 539,529 $ 162,621 $ 532,837 $ 1,234,987 Residential real estate 413,956 129,737 155,895 699,588 Construction, land development, and other land 134,004 4,860 49,752 188,616 Commercial and industrial 556,340 15,347 454,133 1,025,820 Installment and other 4,898 521 7,387 12,806 Lease financing receivables 156,017 — 30,858 186,875 Total loans and leases $ 1,804,744 $ 313,086 $ 1,230,862 $ 3,348,692 December 31, 2017 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 513,622 $ 166,712 $ 211,359 $ 891,693 Residential real estate 400,571 144,562 32,085 577,218 Construction, land development, and other land 97,638 5,946 1,845 105,429 Commercial and industrial 416,499 10,008 94,731 521,238 Installment and other 3,724 462 42 4,228 Lease financing receivables 141,329 — 36,357 177,686 Total loans and leases $ 1,573,383 $ 327,690 $ 376,419 $ 2,277,492 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 2018 or 2017. 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 The outstanding June 30, 2018 December 31, 2017 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 233,680 $ 162,621 $ 235,898 $ 166,712 Residential real estate 189,463 129,737 207,660 144,562 Construction, land development, and other land 12,955 4,860 13,270 5,946 Commercial and industrial 24,275 15,347 18,333 10,008 Installment and other 1,925 521 1,819 462 Total acquired impaired loans $ 462,298 $ 313,086 $ 476,980 $ 327,690 The following table summarizes the changes in accretable yield for acquired impaired loans for the three and six months ended June 30, 2018 and 2017: Three Months Ended Six Months Ended June 30, June 30, 2018 2017 2018 2017 Beginning balance $ 39,300 $ 34,744 $ 36,446 $ 36,868 Additions 3,566 — 3,566 — Accretion to interest income (5,871 ) (8,816 ) (11,562 ) (16,603 ) Reclassification from nonaccretable difference, net 4,311 11,691 12,856 17,354 Ending balance $ 41,306 $ 37,619 $ 41,306 $ 37,619 Acquired non-impaired loans and leases —The Company acquired non-impaired loans as part of the First Evanston acquisition in the amount of $889.1 million. Refer to Note 3—Acquisition of a Business for additional information regarding the transaction. The unpaid June 30, 2018 December 31, 2017 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 545,840 $ 532,837 $ 221,710 $ 211,359 Residential real estate 159,824 155,895 32,605 32,085 Construction, land development, and other land 51,270 49,752 1,926 1,845 Commercial and industrial 475,924 454,133 105,529 94,731 Installment and other 7,813 7,387 355 42 Lease financing receivables 32,524 30,858 37,476 36,357 Total acquired non-impaired loans and leases $ 1,273,195 $ 1,230,862 $ 399,601 $ 376,419

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	6 Months Ended
	Jun. 30, 2018
Receivables [Abstract]
Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	Note 6—Allowance for Loans and leases The following June 30, 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 $ 5,319 $ 1,564 $ 201 $ 7,763 $ 61 $ 2,732 $ 17,640 Provisions 1,336 84 131 1,956 1 448 3,956 Charge-offs (202 ) — — (1,596 ) (32 ) (555 ) (2,385 ) Recoveries — — — 246 — 230 476 Ending balance $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 Six months ended Beginning balance $ 4,794 $ 1,638 $ 222 $ 7,418 $ 41 $ 2,593 $ 16,706 Provisions 2,270 10 528 5,380 21 862 9,071 Charge-offs (611 ) — (418 ) (4,681 ) (32 ) (1,065 ) (6,807 ) Recoveries — — — 252 — 465 717 Ending balance $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 Ending balance: Individually evaluated for impairment $ 2,199 $ 127 $ — $ 2,555 $ 14 $ — $ 4,895 Collectively evaluated for impairment 2,752 1,171 310 4,940 13 2,855 12,041 Loans acquired with deteriorated credit quality 1,502 350 22 874 3 — 2,751 Total allowance for loan and lease losses $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 June 30, 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 $ 16,397 $ 2,273 $ — $ 14,889 $ 14 $ — $ 33,573 Collectively evaluated for impairment 1,055,969 567,578 183,756 995,584 12,271 186,875 3,002,033 Loans acquired with deteriorated credit quality 162,621 129,737 4,860 15,347 521 — 313,086 Total loans and leases $ 1,234,987 $ 699,588 $ 188,616 $ 1,025,820 $ 12,806 $ 186,875 $ 3,348,692 June 30, 2017 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 $ 2,047 $ 2,417 $ 417 $ 4,836 $ 331 $ 1,769 $ 11,817 Provisions (releases) 1,674 (453 ) (90 ) 1,637 13 734 3,515 Charge-offs (53 ) (129 ) — (784 ) — (767 ) (1,733 ) Recoveries — — — — — 370 370 Ending balance $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 Six months ended Beginning balance $ 1,945 $ 2,483 $ 742 $ 4,196 $ 334 $ 1,223 $ 10,923 Provisions (releases) 2,014 (452 ) (415 ) 2,492 10 1,757 5,406 Charge-offs (291 ) (196 ) — (999 ) — (1,537 ) (3,023 ) Recoveries — — — — — 663 663 Ending balance $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 Ending balance: Individually evaluated for impairment $ 396 $ 275 $ — $ 1,638 $ 326 $ — $ 2,635 Collectively evaluated for impairment 1,550 1,219 302 2,898 5 2,106 8,080 Loans acquired with deteriorated credit quality 1,722 341 25 1,153 13 — 3,254 Total allowance for loan and lease losses $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 June 30, 2017 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 $ 8,675 $ 1,271 $ 565 $ 3,081 $ 327 $ — $ 13,919 Collectively evaluated for impairment 632,353 421,096 86,240 452,693 2,633 171,161 1,766,176 Loans acquired with deteriorated credit quality 188,161 162,349 5,830 12,400 555 — 369,295 Total loans and leases $ 829,189 $ 584,716 $ 92,635 $ 468,174 $ 3,515 $ 171,161 $ 2,149,390 The Company increased the allowance for loan and lease losses by $2.0 million and $3.0 million for the three and six months ended June 30, 2018, respectively. The Company increased the allowance for loan and lease losses by $2.2 million and $3.0 million for three and six months ended June 30, 2017, respectively. For acquired impaired loans, the Company decreased the allowance for loan and lease losses by $778,000 and $1.1 million for the three and six months ended June 30, 2018, respectively. The Company increased the allowance for loan and lease losses for acquired impaired loans by $1.5 million and $1.6 million for the three and six months ended June 30, 2017, respectively. The following and June 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 10,735 $ 12,211 $ — Residential real estate 1,935 1,910 — Commercial and industrial 4,391 5,438 — With an allowance recorded Commercial real estate 5,662 5,975 2,199 Residential real estate 338 334 127 Commercial and industrial 10,498 11,447 2,555 Installment and other 14 14 14 Total impaired loans $ 33,573 $ 37,329 $ 4,895 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 11,425 $ 12,936 $ — Residential real estate 2,075 2,046 — Commercial and industrial 5,470 6,774 — With an allowance recorded Commercial real estate 2,459 2,634 1,101 Residential real estate 354 351 158 Commercial and industrial 9,314 9,724 2,692 Installment and other 14 14 14 Total impaired loans $ 31,111 $ 34,479 $ 3,965 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 six months ended as follows: June 30, 2018 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 10,013 $ 436 Residential real estate 1,959 25 Commercial and industrial 7,283 99 With an allowance recorded Commercial real estate 4,587 183 Residential real estate 347 3 Commercial and industrial 8,784 233 Installment and other 14 979 Total impaired loans $ 32,987 $ 1,958 June 30, 2017 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 4,573 $ 199 Residential real estate 578 24 Construction, land development and other land 364 15 Commercial and industrial 1,119 43 With an allowance recorded Commercial real estate 667 — Residential real estate 240 3 Construction, land development and other land 87 — Commercial and industrial 2,047 263 Installment and other 159 9 Total impaired loans $ 9,834 $ 556 For purposes The following June 30, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 938,889 $ 533,937 $ 151,868 $ 840,647 $ 12,253 $ 184,166 $ 2,661,760 Watch 96,967 30,482 28,762 118,385 3 140 274,739 Special Mention 22,353 2,815 3,126 31,955 15 964 61,228 Substandard 14,157 2,617 — 19,486 14 1,289 37,563 Doubtful — — — — — 316 316 Loss — — — — — — — Total $ 1,072,366 $ 569,851 $ 183,756 $ 1,010,473 $ 12,285 $ 186,875 $ 3,035,606 December 31, 2017 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 638,066 $ 398,743 $ 73,935 $ 415,163 $ 3,732 $ 174,672 $ 1,704,311 Watch 58,217 29,165 22,380 67,024 20 190 176,996 Special Mention 14,645 2,251 3,168 13,535 — 1,293 34,892 Substandard 14,053 2,497 — 15,508 14 1,259 33,331 Doubtful — — — — — 272 272 Loss — — — — — — — Total $ 724,981 $ 432,656 $ 99,483 $ 511,230 $ 3,766 $ 177,686 $ 1,949,802 The following tables summarize contractual delinquency information for acquired non-impaired and originated loans and leases by category at June 30, 2018 and December 31, 2017: June 30, 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 $ 544 $ 636 $ — $ 11,534 $ 12,714 $ 1,059,652 $ 1,072,366 Residential real estate 492 15 — 1,619 2,126 567,725 569,851 Construction, land development, and other land — — — — — 183,756 183,756 Commercial and industrial 560 4,244 197 11,861 16,862 993,611 1,010,473 Installment and other 635 — — 14 649 11,636 12,285 Lease financing receivables 518 462 — 714 1,694 185,181 186,875 Total $ 2,749 $ 5,357 $ 197 $ 25,742 $ 34,045 $ 3,001,561 $ 3,035,606 December 31, 2017 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 $ 4,783 $ 968 $ — $ 8,459 $ 14,210 $ 710,771 $ 724,981 Residential real estate 148 — — 2,092 2,240 430,416 432,656 Construction, land development, and other land — — — — — 99,483 99,483 Commercial and industrial 6,667 967 — 4,348 11,982 499,248 511,230 Installment and other 18 — — 14 32 3,734 3,766 Lease financing receivables 997 638 — 851 2,486 175,200 177,686 Total $ 12,613 $ 2,573 $ — $ 15,764 $ 30,950 $ 1,918,852 $ 1,949,802 At June 30, 2018 and December 31, 2017, the a of $1.1 million and $357,000 June 30, 2018 and December 31, 2017 Loans modified three and six months ended June 30, 2018 At June 30, 2018 and December 31, 2017, the During the three months ended June 30, 2018 and 2017, the six months ended June 30, 2018 and 2017 and credits to

Servicing Assets

Servicing Assets	6 Months Ended
	Jun. 30, 2018
Transfers And Servicing [Abstract]
Servicing Assets	Note 7—Servicing Activity for the six months ended June 30, 2018 is Six Months Ended June 30, 2018 2017 Beginning balance $ 21,400 $ 21,091 Additions, net 4,191 2,948 Changes in fair value (4,004 ) (2,615 ) Ending balance $ 21,587 $ 21,424 Loans serviced as of June 30, 2018 and December 31, 2017: June 30, December 31, 2018 2017 Loan portfolios serviced for: SBA guaranteed loans 1,111,551 1,021,143 USDA guaranteed loans 84,019 91,758 Total $ 1,195,570 $ 1,112,901 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 condition 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	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 and 2017. Six Months Ended June 30, 2018 2017 Beginning balance $ 10,626 $ 16,570 Net additions to OREO 1,067 2,490 Dispositions of OREO (5,231 ) (6,056 ) Valuation adjustments (60 ) (320 ) Ending balance $ 6,402 $ 12,684 At June 30, 2018 and December 31, 2017, the balance of real estate owned included $843,000 and $3.6 million, respectively, of foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property. At June 30, 2018 and December 31, 2017, the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings were in process is $4.3 million and $1.9 million, respectively.

Goodwill, Core Deposit Intangib

Goodwill, Core Deposit Intangible and Other Intangible Assets	6 Months Ended
	Jun. 30, 2018
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 table summarizes the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the six months ended June 30, 2018 and 2017: Six Months Ended June 30, 2018 2017 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Deposit Intangible Customer Relationship Intangible Beginning balance $ 54,562 $ 16,720 $ — $ 51,975 $ 19,776 $ — Additions 72,974 19,060 3,216 — — — Amortization or accretion — (1,863 ) (22 ) — (1,529 ) — Ending balance $ 127,536 $ 33,917 $ 3,194 $ 51,975 $ 18,247 $ — Accumulated amortization or accretion N/A $ 15,329 22 N/A $ 11,939 N/A Weighted average remaining amortization or accretion period N/A 7.1 Years 11.9 Years N/A 6.1 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 detail. Additionally, the Company had other intangible assets of $29,000 and $36,000 as of June 30, 2018 and December 31, 2017, respectively, associated with trademark-related transactions. The following table presents the estimated amortization expense for core deposit intangible, customer relationship intangible, and other intangible assets recognized at June 30, 2018: Estimated Amortization 2018 $ 3,644 2019 6,942 2020 6,478 2021 6,026 2022 5,578 Thereafter 8,472 Total $ 37,140

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2018
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 rates for the six months ended June 30, 2018 and 2017 were 20.0% and 40.5%, respectively. The reduction in the effective tax rate is primarily a result of 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 TCJ Act (enacted on December 22, 2017) on our net deferred tax assets. The re-measurement of our net deferred tax assets due to the TCJ Act was determined to be provisional at March 31, 2018. Net deferred tax assets increased to $48.9 million at June 30, 2018 compared to $47.4 million at December 31, 2017. The net increase in the total net deferred tax assets recorded as of June 30, 2018 was a result of an increase related to the acquisition of First Evanston, offset with a reduction due to the utilization of net operating loss carryforward deferred tax assets.

Deposits

Deposits	6 Months Ended
	Jun. 30, 2018
Deposits [Abstract]
Deposits	Note 11—Deposits The composition of deposits was as follows as of June 30, 2018 and December 31, 2017: June 30, December 31, 2018 2017 Non-interest bearing demand deposits $ 1,193,057 $ 760,887 Interest bearing checking accounts 287,330 186,611 Money market demand accounts 617,108 349,862 Other savings 487,130 437,212 Time deposits (below $250,000) 879,643 627,255 Time deposits ($250,000 and above) 180,609 81,502 Total deposits $ 3,644,877 $ 2,443,329

Federal Home Loan Bank Advances

Federal Home Loan Bank Advances	6 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank Advances	Note 12—Federal The following June 30, December 31, 2018 2017 Federal Home Loan Bank advances $ 420,000 $ 361,506 Weighted average cost 2.01 % 1.49 % At June 30, 2018, fixed-rate advances totaled $260.0 million with interest rates of 2.03% and 2.13% and maturities of July 2018 and September 2018. June 30, 2018, July The Company’s required investment in FHLB stock is $1 for every $20 in advances. Refer to Note 4 Securities for additional discussion. At June 30, 2018 and December 31, 2017, the Bank has additional borrowing capacity from the FHLB of $749.6 million and $795.0 million, respectively, 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 Hedge Activities for additional information.

Other Borrowings

Other Borrowings	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Other Borrowings	Note 13—Other Borrowings The following is a summary of the Company’s other borrowings as of June 30, 2018 and December 31, 2017: June 30, December 31, 2018 2017 Securities sold under agreements to repurchase $ 24,653 $ 31,187 Line of credit — — Total $ 24,653 $ 31,187 Securities On June 30, 2018 The following June 30, December 31, 2018 2017 Federal Reserve Bank of Chicago discount window line $ 329,627 $ 144,248 Available federal funds lines 55,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Junior Subordinated Debentures	Note 14—Junior Subordinated Debentures At June 30, 2018 and December 31, 2017, the Name of Trust Aggregate Principal Amount June 30, 2018 Aggregate Principal Amount December 31, 2017 Stated Maturity Contractual Rate at June 30, 2018 Interest Rate Spread Metropolitan $ 35,000 $ 35,000 March 5.12 % 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 — March 15, 2035 4.12 % Three-month LIBOR + 1.78% Total liability, at par 46,500 36,500 Discount (10,048 ) (8,853 ) Total liability, at carrying value $ 36,452 $ 27,647 June 30, 2018 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% and 5.09% at June 30, 2018 and December 31, 2017, respectively), 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. There was no accrued interest payable as of June 30, 2018 or December 31, 2017. 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% (4.12% at June 30, 2018), 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	6 Months Ended
	Jun. 30, 2018
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 Statements of Financial Condition. 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 2018 $ 1,823 2019 3,183 2020 2,652 2021 2,321 2022 1,355 Thereafter 2,870 Total $ 14,204 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 Bank 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 Bank has in particular classes of financial instruments. The Company’s exposure The following June 30, 2018 and December 31, 2017 June 30, December 31, 2018 2017 Fixed Rate Variable Rate Fixed Rate Variable Rate Commitments to extend credit $ 78,076 $ 947,386 $ 55,924 $ 467,429 Standby letters of credit 2,360 26,369 1,226 3,337 Total $ 80,436 $ 973,755 $ 57,150 $ 470,766 Commitments Standby letters Commitments

Fair Value Measurement

Fair Value Measurement	6 Months Ended
	Jun. 30, 2018
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. 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 swaps 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 June 30, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 44,423 $ 44,423 $ — $ — U.S. Government agencies 145,009 — 145,009 — Obligations of states, municipalities, and political subdivisions 59,293 — 58,604 689 Residential mortgage-backed securities Agency 299,534 — 299,534 — Non-agency 61,963 — 61,963 — Commercial mortgage-backed securities Agency 73,253 — 73,253 — Non-agency 30,104 — 30,104 — Corporate securities 37,590 — 37,590 — Other securities 6,656 2,844 3,121 691 Servicing assets 21,587 — — 21,587 Derivative assets 13,063 — 13,063 — Financial liabilities Derivative liabilities 2,869 — 2,867 2 Fair Value Measurements Using December 31, 2017 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 14,863 $ 14,863 $ — $ — U.S. Government agencies 52,958 — 52,958 — Obligations of states, municipalities, and political subdivisions 33,170 — 32,795 375 Residential mortgage-backed securities Agency 307,457 — 307,457 — Non-agency 39,514 — 39,514 — Commercial mortgage-backed securities Agency 69,043 — 69,043 — Non-agency 30,971 — 30,971 — Corporate securities 29,976 — 29,976 — Other securities 5,284 1,921 2,686 677 Servicing assets 21,400 — — 21,400 Derivative assets 5,981 — 5,981 — Financial liabilities Derivative liabilities 994 — 994 — 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 six months ended June 30, 2018 or the year ended December 31, 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): Six Months Ended June 30, 2018 2017 2018 2017 Investment Securities Servicing Assets Balance, beginning of period $ 1,052 $ 1,080 $ 21,400 $ 21,091 Acquired assets at fair value 314 — — — Additions, net — — 4,191 2,948 Amortization 3 2 — — Change in unrealized gain 11 (5 ) — — Change in fair value — — (4,004 ) (2,615 ) Balance, end of period $ 1,380 $ 1,077 $ 21,587 $ 21,424 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 1.3%—2.4% 1.8 % Decrease Single issuer trust preferred Discounted cash flow Probability of default 4.9%—7.0% 6.1 % Decrease Servicing assets Discounted cash flow Prepayment speeds 4.6%—23.0% 10.0 % Decrease Discount rate 6.6%—22.0% 14.1 % Decrease Expected weighted average loan life 0.2—7.4 years 5.3 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. 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 June 30, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 14,198 $ — $ — $ 14,198 Residential real estate 2,146 — — 2,146 Construction, land development, and other land — — — — Commercial and industrial 12,334 — — 12,334 Installment and other — — — — Assets held for sale 11,428 — — 11,428 Other real estate owned 6,402 — — 6,402 Fair Value Measurements Using December 31, 2017 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 12,783 $ — $ — $ 12,783 Residential real estate 2,271 — — 2,271 Construction, land development, and other land — — — — Commercial and industrial 12,092 — — 12,092 Installment and other — — — — Assets held for sale 9,779 — — 9,779 Other real estate owned 10,626 — — 10,626 The following Financial Instruments Valuation Technique Unobservable Inputs Range of Inputs Impact to Valuation from an Increased or Higher Input Value Impaired loans (excluding acquired impaired loans) Appraisals Appraisal adjustments, sales costs and other discount adjustments for market conditions 6% - 10% Decrease Assets held for sale List price, contract price Sales costs and other discount adjustments for market conditions 7% Decrease Other real estate owned Appraisals Appraisal adjustments, sales costs and other discount adjustments for market conditions 7% - 20% Decrease 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 standby 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 June 30, December 31, Fair Value 2018 2017 Hierarchy Level Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets Cash and due from banks 1 $ 25,299 $ 25,299 $ 19,404 $ 19,404 Interest bearing deposits with other banks 2 127,417 127,417 38,945 38,945 Securities held-to-maturity 2 106,613 104,411 117,163 117,277 Other restricted stock 2 18,977 18,977 16,343 16,343 Loans held for sale 3 5,822 6,494 5,212 5,851 Loans and lease receivables, net 3 3,329,005 3,288,358 2,260,786 2,240,235 Accrued interest receivable 3 10,670 10,670 7,670 7,670 Financial liabilities Non-interest bearing deposits 2 1,193,057 1,193,057 760,887 760,887 Interest bearing deposits 2 2,451,820 2,447,100 1,682,442 1,678,535 Accrued interest payable 2 2,562 2,562 1,306 1,306 Line of credit 2 — — — — Federal Home Loan Bank advances 2 420,000 420,000 361,506 361,500 Securities sold under repurchase agreement 2 24,653 24,653 31,187 31,187 Junior subordinated debentures 3 36,452 42,475 27,647 33,907

Derivative Instruments and Hedg

Derivative Instruments and Hedge Activities	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 and December 31, 2017: June 30, 2018 December 31, 2017 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 $ 10,238 $ — $ 250,000 $ 5,030 $ 38 Derivatives not designated as hedging instruments Other interest rate swaps 214,015 2,825 2,867 94,726 951 956 Other credit derivatives 1,250 — 2 — — — Total derivatives $ 465,265 $ 13,063 $ 2,869 $ 344,726 $ 5,981 $ 994 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 June 30, 2018 and December 31, 2017. The aggregate fair value of the swaps is recorded in other assets or other liabilities with changes in fair value recorded in other comprehensive income (loss), net of taxes, to the extent effective. The amount included in accumulated other comprehensive income (loss) would be reclassified to current interest incurred from the hedged FHLB advances when it affects earnings. 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. The Company expects the hedges to remain highly effective during the remaining terms of the swaps and did not recognize any hedge ineffectiveness in current earnings during the three or six months ended June 30, 2018 and 2017. Interest recorded on these swap transactions reduced FHLB interest expense by $374,000 The following table reflects the cash flow hedges as of June 30, 2018: Notional amounts $ 250,000 Derivative assets fair value 10,238 Derivative liabilities fair value — Weighted average pay rates 1.67 % Weighted average receive rates 1.63 % Weighted average maturity 4.2 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 six months ended: June 30, 2018 June 30, 2017 Amount of Gain Recognized in OCI (Effective Portion) Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income (Ineffective Portion) Amount of Gain (Loss) Recognized in OCI (Effective Portion) Amount of Loss Reclassified from OCI to Income as an Increase to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income (Ineffective Portion) Interest rate swaps $ 5,632 $ 435 $ — $ (1,425 ) $ (267 ) $ — Other interest rate swaps —The total combined notional amount was $214.0 million as of June 30, 2018 with maturities ranging from December 2018 to April 2028. The fair values of the interest rate swap agreements are reflected in other assets and other liabilities with corresponding gains or losses reflected in non-interest income. During the three and six months ended June 30, 2018, there were $946,000 of transaction fees, included in other non-interest income, related to these derivative instruments. During the three and six months ended June 30, 2017, transaction fees were $65,000 and $179,000, respectively. The following table reflects other interest rate swaps as of June 30, 2018: Notional amounts $ 214,015 Derivative assets fair value 2,825 Derivative liabilities fair value 2,867 Weighted average pay rates 4.66 % Weighted average receive rates 4.04 % Weighted average maturity 5.8 years Other credit derivative— The total notional amount was $1.3 million as of June 30, 2018. There were no credit derivatives as of December 31, 2017. The fair value of the other credit derivative is reflected in other liabilities with corresponding gains or losses reflected in non-interest income. The credit valuation adjustment (“CVA”) related to the other credit derivative resulted in an increase to other non-interest income during the three and six months ended June 30, 2018, of $1,000 and $24,000, respectively. 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 and six months ended June 30, 2018, the CVA resulted in a decrease to non-interest income of $65,000 and $38,000, respectively. During the three and six months ended June 30, 2017, the CVA resulted in a decrease to non-interest income of $17,000 and $30,000, respectively. The Company has entered into a risk participation agreement with a counterparty bank to assume a portion of the credit risk related to borrower transactions. The credit risk related to this derivative is managed through the Company’s loan underwriting process. 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: June 30, 2018 December 31, 2017 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 13,063 $ 2,869 $ 5,981 $ 994 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 13,063 $ 2,869 $ 5,981 $ 994 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (1,091 ) (1,091 ) (232 ) (232 ) Collateral posted (11,972 ) (1,775 ) (5,371 ) (745 ) Net credit exposure $ — $ 3 $ 378 $ 17 As of June 30, 2018, the counterparties posted collateral of $12.1 million, which resulted in no excess collateral with the Company. For purposes of this disclosure, the amount of posted collateral by the counterparties is limited to the amount offsetting the derivatives asset.

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2018
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 initial public offering (“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 and are available for issuance 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 During 2018, the Company granted 126,157 shares of restricted common stock, par value $0.01 per share. Of this total, 101,559 restricted shares will vest ratably over four years on each anniversary of the grant date, 11,165 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 shares will vest on the third anniversary of the grant date. As of June 30, 2018, there were 1,355,545 shares available for future grants under the Omnibus Plan. The following table discloses the changes in restricted shares for the six months ended June 30, 2018: Omnibus Plan Number of Shares Weighted Average Grant Date Fair Value Beginning balance, January 1, 2018 70,398 $ 20.31 Granted 126,157 $ 22.38 Vested — $ — Forfeited (2,100 ) $ 20.84 Ending balance outstanding at June 30, 2018 194,455 $ 21.65 No restricted shares vested during the six months ended June 30, 2018. 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 six months ended June 30, 2018 and 2017: Six Months Ended June 30, 2018 2017 Total share-based compensation - restricted stock $ 326 $ — Income tax benefit 91 — Unrecognized compensation expense 3,691 — Weighted-average amortization period remaining 3.3 years — The fair value of the unvested restricted stock awards at June 30, 2018 was $4.3 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 1,683,270 shares remain outstanding under the BYB Plan at June 30, 2018. 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 fair values of options under the BYB Plan were determined using the following assumptions as of the grant dates: Time Options Grants 2016 2015 Risk-free interest rate 1.34% - 1.40% 1.68% - 1.85% Expected term (years) 5.2 - 5.6 5.7 - 6.3 Expected stock price volatility 20.39 % 16.18%-16.55% Expected dividend yield 0.00 % 0.00 % Weighted average grant date fair value $ 3.55 $ 2.25 Performance Options Grants 2016 2015 Risk-free interest rate Implied forward rates Implied forward rates Expected term (years) Variable Variable Expected stock price volatility 20.34% - 20.39% 16.18%-16.55% Expected dividend yield 0.00 % 0.00 % Weighted average grant date fair value $ 3.75 $ 1.65 The following table discloses the activity in shares subject to options and the weighted average exercise prices, in actual dollars, for the six months ended June 30, 2018: BYB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2018 1,783,020 $ 11.91 $ 19,718 7.6 Granted — Expired — Exercised (94,750 ) 11.98 $ 988 Forfeited (5,000 ) 16.25 Ending balance outstanding at June 30, 2018 1,683,270 $ 11.89 $ 17,583 7.1 Exercisable at June 30, 2018 1,516,670 $ 11.42 $ 16,568 7.0 A total of 94,750 stock options were exercised during the six months ended June 30, 2018. During the six months ended June 30, 2018, proceeds from the exercise of stock options were $1.1 million and related tax benefit was $275,000. There were no stock options exercised during the year ended December 31, 2017. A total of 307,163 stock options vested during the six months ended June 30, 2018. 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 six months ended June 30, 2018 and 2017: Six Months Ended June 30, 2018 2017 Total share-based compensation - stock options $ 450 $ 571 Income tax benefit 125 227 Unrecognized compensation expense 271 1,181 Weighted-average amortization period remaining 1.3 years 1.4 years Pursuant to the terms of the Merger Agreement, upon the Effective Time, each outstanding First Evanston Option held by a participant (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”, and collectively, the “Adjusted Options”). 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 “Conversion Calculation”). 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 six months ended June 30, 2018: FEB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2018 — $ — $ — — Granted 680,787 11.26 $ 7,544 Expired — Exercised — Forfeited — Ending balance outstanding at June 30, 2018 680,787 $ 11.26 $ 7,544 5.3 Exercisable at June 30, 2018 680,787 $ 11.26 $ 7,544 5.3 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	6 Months Ended
	Jun. 30, 2018
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 2,364,057 and 1,798,223 shares of common stock were outstanding as of June 30, 2018 and 2017, respectively. There were 194,455 restricted stock awards outstanding at June 30, 2018. There were no restricted stock awards outstanding at June 30, 2017. The following represent the calculation of basic and diluted earnings per share for the periods presented: Three Months Ended June 30, Six Months Ended June 30, 2018 2017 2018 2017 Net income $ 2,768 $ 6,146 $ 9,536 $ 12,706 Less: Dividends on preferred shares 198 10,697 391 10,886 Net income available (loss attributable) to common stockholders $ 2,570 $ (4,551 ) $ 9,145 $ 1,820 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 31,614,973 24,667,587 30,459,495 24,642,287 Incremental shares 953,423 — 988,825 464,600 Weighted-average common stock outstanding (dilutive) 32,568,396 24,667,587 31,448,320 25,106,887 Basic earnings per common share $ 0.08 $ (0.18 ) $ 0.30 $ 0.07 Diluted earnings per common share $ 0.08 $ (0.18 ) $ 0.29 $ 0.07

Stockholders' Equity

Stockholders' Equity	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Stockholders' Equity	Note 20—Stockholders’ Equity A summary of the Company’s preferred and common stock at June 30, 2018 and December 31, 2017 is as follows: June 30, December 31, 2018 2017 Series B 7.5% fixed 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 36,218,955 29,317,298 Shares outstanding 36,218,955 29,317,298 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. For the three months ended June 30, 2018, the Company declared and paid dividends on the Series B preferred stock of $198,000, compared to $196,000 for the three months ended June 30, 2017. For the six months ended June 30, 2018, the Company declared and paid dividends on the Series B preferred stock of $391,000, compared to $385,000 for the six months ended June 30, 2017.

Consolidated Statements of Ch28

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 and June 30, 2017: (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, 2017 $ 2,233 $ (9,501 ) $ (7,268 ) Other comprehensive (loss) income, net of tax (693 ) 1,549 856 Balance, June 30, 2017 $ 1,540 $ (7,952 ) $ (6,412 ) 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 3,750 (8,235 ) (4,485 ) Balance, June 30, 2018 $ 7,350 $ (17,685 ) $ (10,335 )

Basis of Presentation (Policies

Basis of Presentation (Policies)	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 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, 2017, 2016, and 2015. 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. No 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. During the three months ended March 31, 2018, we revised our previously issued 2017 consolidated financial statements to properly record a deferred tax liability associated with the bad debt recapture assumed from the acquisition of Ridgestone Financial Services, Inc. (“Ridgestone”) and its subsidiaries on October 14, 2016. The acquisition of Ridgestone was accounted for using the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations (“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 2017. We evaluated the effect of the error to our previously issued consolidated financial statements in accordance with Securities and Exchange Commission Staff Accounting Bulletin No. 99 and No. 108, and, based upon quantitative and qualitative factors, determined that the error was not material to our previously issued consolidated financial statements. Accordingly, we have reflected the change in 2017 and revised our Consolidated Statements of Financial Condition disclosed herein. Consolidated financial statements for periods not presented herein will be revised, as applicable, as they are included in future filings. All financial information presented in the accompanying notes to these consolidated financial statements was revised to reflect the change. The change did not affect net income or stockholders’ equity for the periods impacted. The following table presents the effect of the aforementioned revisions to our Consolidated Statements of Financial Condition as of December 31, 2017: December 31, 2017 (dollars in thousands) As Reported Adjustment As Revised Goodwill $ 51,975 $ 2,587 $ 54,562 Deferred tax assets, net 49,963 (2,587 ) 47,376 Total assets 3,366,130 — 3,366,130
Recently Issued Accounting Pronouncements	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. 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 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. Under the terms of ASU No. 2015-14 the standard is effective for interim and annual periods beginning after December 15, 2017. Early application is permitted only as of annual reporting periods beginning after December 15, 2016, including interim reporting periods within that reporting period. For financial reporting purposes, the standard allows for either full retrospective adoption, meaning the standard is applied to all of the periods presented, or modified retrospective adoption, meaning the standard is applied only to the most current period presented in the financial statements with the cumulative effect of initially applying the standard recognized at the date of initial application. The Company is currently evaluating the provisions of ASU No. 2014-09 to determine the potential impact the standard will have on the Company’s Consolidated Financial Statements. As a financial institution, the Company’s largest component of revenue, interest income, is excluded from the scope of this ASU. The Company is currently evaluating which, if any, of its sources of non-interest income will be impacted by this ASU. Assuming the Company remains an emerging growth company, the Company expects to adopt this new guidance on January 1, 2019, with a cumulative effect adjustment to opening retained earnings, if such adjustment is deemed to be significant. In April 2016, FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing . The amendments in this ASU do not change the core principle of the guidance in Topic 606. Rather, 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. The amendments in this ASU affect the guidance in ASU 2014-09, discussed above, which is not yet effective. The effective date and transition requirements for the amendments in this ASU are the same as the effective date and transition requirements in Topic 606, Revenues from Contracts with Customers . The Company is evaluating the provisions of this ASU in conjunction with ASU No. 2014-09 to determine the potential impact Topic 606 and its amendments will have on the Company’s Consolidated Financial Statements. In May 2016, FASB issued ASU No. 2016-12, Narrow-Scope Improvements and Practical Expedients Revenue from Contracts with Customers In November 2017, FASB issued ASU No. 2017-14, amending ASC Topic 606, Revenue from Contracts with Customers Revenue from Contracts with Customers Recognition and Measurement of Financial Assets and Financial Liabilities Recognition and Measurement of Financial Assets and Financial Liabilities In March 2018, FASB issued ASU No. 2018-03, Recognition and Measurement of Financial Assets and Financial Liabilities 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 lease contracts where the Company is a lessee. 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 with early adoption permitted. The Company is evaluating the new guidance and its impact on the Company’s Consolidated Statements of Operations and Consolidated Statements of Financial Condition. 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) or 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. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company is evaluating the new guidance and its impact on the Company’s Consolidated Statements of Operations and Consolidated Statements of Financial Condition. In June 2018, the FASB issued ASU 2018-07, Improvements to Nonemployee Share-based Payment Accounting Revenue from Contracts with Customers 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. 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. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company is currently evaluating the provisions of ASU No. 2016-15 to determine the potential impact the new standard will have on the Company’s Consolidated Financial Statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (230), Restricted Cash Income Taxes (Topic 740) In October 2016, the FASB issued ASU No. 2016-16, Income Taxes, Intra-Entity Transfers of Assets Other Than Inventory . The ASU was issued to improve the accounting for income tax consequences of intra-entity transfers of assets other than inventory. Current GAAP prohibits the recognition of current and deferred income taxes for an intra-entity asset transfer until the asset has been sold to an outside party; this update clarifies that an entity should recognize the income tax consequences of an intra-entity transfer of assets other than inventory when the transfer occurs. The amendment is effective for annual reporting periods beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption of the update is permitted. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company does not expect this ASU to have a material impact on the Company’s Consolidated Financial Statements. 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. Early adoption is permitted. Assuming the Company remains an emerging growth company, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company does not expect a material impact of this ASU on the Company’s Consolidated Financial Statements. Intangibles—Goodwill and Other (Topic 350) In January 2017, FASB issued ASU No. 2017-04, Simplifying the Test for Goodwill Impairment . The amendments in this ASU are intended to reduce the cost and complexity of the goodwill impairment test by eliminating step two from the impairment test. The amendments modify the concept of impairment from the condition that exists when the carrying amount of goodwill exceeds its implied fair value to the condition that exists when the carrying amount of a reporting unit exceeds its fair value. Under the amendments in this ASU, an entity will perform its annual, or interim, goodwill impairment test by comparing the fair value of the reporting unit with its carrying amount. An impairment charge should be recognized for the amount which the carrying amount exceeds the reporting unit’s fair value; however, the loss recognized should not exceed the total amount of goodwill allocated to that reporting unit. The amendments in this ASU are effective for the Company’s annual or any interim goodwill impairment test in fiscal years beginning after December 15, 2019. Early adoption is permitted for interim or annual goodwill impairment tests performed on testing dates after January 1, 2017. The Company early adopted these amendments in 2017, which did not have a material impact on the Company’s Consolidated Financial Statements. Other Income (Subtopic 610-20) In February 2017, the FASB issued ASU No. 2017-05, Other Income-Gains and Losses from the Derecognition of Nonfinancial Assets . This ASU will clarify the scope of Subtopic 610-20 and add guidance for partial sales of nonfinancial assets. The amendments should be applied either on retrospectively to each period presented or with a modified retrospective approach. The amendment is effective for annual periods beginning after December 15, 2018, and interim periods within annual periods beginning after December 15, 2019. The Company is currently evaluating the provisions of ASU No. 2017-05 to determine the potential impact the new standard will have on the Company’s Consolidated Financial Statements. 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. Earnings Per Share (Topic 260), Distinguishing Liabilities from Equity (Topic 480), Derivatives and Hedging (Topic 815) In July 2017, FASB issued ASU No. 2017-11, (Part I) Accounting for Certain Financial Instruments with Down Round Features, (Part II) Replacement of the Indefinite Deferral for Mandatorily Redeemable Financial Instruments of Certain Nonpublic Entities and Certain Mandatorily Redeemable Noncontrolling Interests with a Scope Exception . The ASU simplifies the accounting for certain financial instruments with down round features, a provision in an equity-linked financial instrument (or embedded feature) that provides a downward adjustment of the current exercise price based on the price of future equity offerings. Down round features are common in warrants, convertible preferred shares, and convertible debt instruments. The ASU requires companies to disregard the down round feature when assessing whether the instrument is indexed to its own stock, for purposes of determining liability or equity classification. Companies that provide earnings per share (EPS) data will adjust their basic EPS calculation for the effect of the feature when triggered (i.e., when the exercise price of the related equity-linked financial instrument is adjusted downward because of the down round feature) and will also recognize the effect of the trigger within equity. 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. 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. 2017‑11 to determine the potential impact the new standard will have 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 to retained earnings. Financial Services—Depository and Lending (Topic 942) In May 2018, FASB issued ASU No. 2018-06, Codification Improvements to Topic 942, Depository and Lending — Income Taxes . The amendments in this ASU supersede the guidance within Subtopic 942-741 that has been rescinded by the OCC and no longer relevant. A cross-reference between Subtopic 740-30, Income Taxes—Other Considerations or Special Areas, and Subtopic 942-740 is being added to the remaining guidance in Subtopic 740-30 to improve the usefulness of the codification. The amendments in this Update are effective upon issuance, as no accounting requirements are affected. The amendments in this ASU do not have a material impact on the Company’s Consolidated Financial Statements.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	6 Months Ended
	Jun. 30, 2018
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Schedule of Aforementioned Revisions to Consolidated Statements of Financial Condition	The following table presents the effect of the aforementioned revisions to our Consolidated Statements of Financial Condition as of December 31, 2017: December 31, 2017 (dollars in thousands) As Reported Adjustment As Revised Goodwill $ 51,975 $ 2,587 $ 54,562 Deferred tax assets, net 49,963 (2,587 ) 47,376 Total assets 3,366,130 — 3,366,130

Acquisition of a Business (Tabl

Acquisition of a Business (Tables)	6 Months Ended
	Jun. 30, 2018
Business Combinations [Abstract]
Summary of Preliminary Estimates of fair Values of Assets and Liabilities Assumed as of Acquisition Date	The following table presents a summary of the preliminary estimates of 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 16,778 Other intangible assets 22,276 Deferred tax assets, net 2,055 Other assets 8,845 Total assets acquired 1,142,766 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 $ 106,157 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 $ 72,974
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 $ 889,115 Gross contractual amounts receivable 1,055,502 Estimate of contractual cash flows not expected to be collected (1) 36,544 Estimate of contractual cash flows expected to be collected 1,018,958 (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 Unaudited Pro Forma Information for Results of Operations	The following table provides the unaudited pro forma information for the results of operations for the three and six months ended June 30, 2018 and 2017, as if the acquisition had occurred on January 1, 2017. 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 security discount accretion, loan discount accretion, intangible assets amortization, deposit premium accretion, fixed assets amortization, and borrowing 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, 2017. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for loan and lease 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 For the Six Months Ended June 30, June 30, 2018 2017 2018 2017 Total revenues (net interest income and non-interest income) $ 61,775 $ 55,995 $ 119,828 $ 111,641 Net income $ 10,709 $ 9,075 $ 21,166 $ 19,073 Earnings (loss) per share—basic $ 0.29 $ (0.05 ) $ 0.58 $ 0.26 Earnings (loss) per share—diluted $ 0.28 $ (0.05 ) $ 0.56 $ 0.26

Securities (Tables)

Securities (Tables)	6 Months Ended
	Jun. 30, 2018
Investments Debt And Equity Securities [Abstract]
Summary of Amortized Cost and Fair Values of Securities Available-for-sale and Held to Maturity	The following June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 44,683 $ 4 $ (264 ) $ 44,423 U.S. Government agencies 146,887 26 (1,904 ) 145,009 Obligations of states, municipalities, and political subdivisions 59,995 110 (812 ) 59,293 Residential mortgage-backed securities Agency 313,823 — (14,289 ) 299,534 Non-agency 63,519 — (1,556 ) 61,963 Commercial mortgage-backed securities Agency 76,332 72 (3,151 ) 73,253 Non-agency 31,612 — (1,508 ) 30,104 Corporate securities 37,707 227 (344 ) 37,590 Other securities 4,610 2,176 (130 ) 6,656 Total $ 779,168 $ 2,615 $ (23,958 ) $ 757,825 June 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,934 $ 28 $ (373 ) $ 23,589 Residential mortgage-backed securities Agency 45,422 — (843 ) 44,579 Non-agency 37,257 — (1,014 ) 36,243 Total $ 106,613 $ 28 $ (2,230 ) $ 104,411 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 14,999 $ — $ (136 ) $ 14,863 U.S. Government agencies 54,248 — (1,290 ) 52,958 Obligations of states, municipalities, and political subdivisions 33,405 100 (335 ) 33,170 Residential mortgage-backed securities Agency 315,103 — (7,646 ) 307,457 Non-agency 39,485 104 (75 ) 39,514 Commercial mortgage-backed securities Agency 70,964 45 (1,966 ) 69,043 Non-agency 31,763 — (792 ) 30,971 Corporate securities 29,573 507 (104 ) 29,976 Other securities 3,627 1,730 (73 ) 5,284 Total $ 593,167 $ 2,486 $ (12,417 ) $ 583,236 December 31, 2017 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 24,030 $ 197 $ (82 ) $ 24,145 Residential mortgage-backed securities Agency 53,731 79 (203 ) 53,607 Non-agency 39,402 174 (51 ) 39,525 Total $ 117,163 $ 450 $ (336 ) $ 117,277
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 June 30, 2018 and December 31, 2017 are summarized as follows: Less than 12 Months 12 Months or Longer Total June 30, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 18 $ 24,695 $ (76 ) $ 9,813 $ (188 ) $ 34,508 $ (264 ) U.S. Government agencies 36 62,216 (92 ) 51,471 (1,812 ) 113,687 (1,904 ) Obligations of states, municipalities and political subdivisions 40 24,271 (564 ) 4,396 (248 ) 28,667 (812 ) Residential mortgage-backed securities Agency 44 30,404 (604 ) 269,131 (13,685 ) 299,535 (14,289 ) Non-agency 7 57,749 (1,350 ) 4,213 (206 ) 61,962 (1,556 ) Commercial mortgage-backed securities Agency 8 7,228 (46 ) 54,473 (3,105 ) 61,701 (3,151 ) Non-agency 5 — — 30,104 (1,508 ) 30,104 (1,508 ) Corporate securities 11 16,946 (133 ) 4,744 (211 ) 21,690 (344 ) Other securities 1 — — 2,844 (130 ) 2,844 (130 ) Total 170 $ 223,509 $ (2,865 ) $ 431,189 $ (21,093 ) $ 654,698 $ (23,958 ) Less than 12 Months 12 Months or Longer Total June 30, 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 27 $ 18,166 $ (327 ) $ 1,538 $ (46 ) $ 19,704 $ (373 ) Residential mortgage-backed securities Agency 20 37,755 (558 ) 6,824 (285 ) 44,579 (843 ) Non-agency 7 32,173 (847 ) 4,070 (167 ) 36,243 (1,014 ) Total 54 $ 88,094 $ (1,732 ) $ 12,432 $ (498 ) $ 100,526 $ (2,230 ) Less than 12 Months 12 Months or Longer Total December 31, 2017 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 5 $ 4,998 $ (2 ) $ 9,865 $ (134 ) $ 14,863 $ (136 ) U.S. Government agencies 9 992 (7 ) 51,966 (1,283 ) 52,958 (1,290 ) Obligations of states, municipalities and political subdivisions 29 16,059 (137 ) 4,453 (198 ) 20,512 (335 ) Residential mortgage-backed securities Agency 41 15,441 (181 ) 292,016 (7,465 ) 307,457 (7,646 ) Non-agency 1 — — 4,565 (75 ) 4,565 (75 ) Commercial mortgage-backed securities Agency 7 — — 57,442 (1,966 ) 57,442 (1,966 ) Non-agency 5 — — 30,971 (792 ) 30,971 (792 ) Corporate securities 3 2,406 (80 ) 2,489 (24 ) 4,895 (104 ) Other securities 1 — — 1,921 (73 ) 1,921 (73 ) Total 101 $ 39,896 $ (407 ) $ 455,688 $ (12,010 ) $ 495,584 $ (12,417 ) Less than 12 Months 12 Months or Longer Total December 31, 2017 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 12 $ 7,409 $ (38 ) $ 1,548 $ (44 ) $ 8,957 $ (82 ) Residential mortgage-backed securities Agency 13 24,344 (107 ) 7,935 (96 ) 32,279 (203 ) Non-agency 3 10,458 (10 ) 4,382 (41 ) 14,840 (51 ) Total 28 $ 42,211 $ (155 ) $ 13,865 $ (181 ) $ 56,076 $ (336 )
Summary of Proceeds From Sales of Securities Available-for-sale and Associated Gains and Losses	The proceeds three and six months ended June 30, 2018 For the Three Months Ended For the Six Months Ended June 30, June 30, 2018 2017 2018 2017 Proceeds $ 544 $ — $ 544 $ 8 Gross gains 4 — 4 8 Gross losses — — — —
Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity	At June 30, 2018, the Amortized Cost Fair Value Available-for-sale Due in one year or less $ 40,479 $ 40,475 Due from one to five years 187,741 186,169 Due from five to ten years 49,553 48,404 Due after ten years 12,036 11,958 Mortgage-backed securities 485,286 464,854 Other securities with no defined maturity 4,073 5,965 Total $ 779,168 $ 757,825 Held-to-maturity Due from one to five years $ 4,060 $ 4,031 Due from five to ten years 11,646 11,442 Due after ten years 8,228 8,116 Mortgage-backed securities 82,679 80,822 Total $ 106,613 $ 104,411

Loan and Lease Receivables (Tab

Loan and Lease Receivables (Tables)	6 Months Ended
	Jun. 30, 2018
Receivables [Abstract]
Schedule of Outstanding Loan and Lease Receivables	Outstanding loan and lease receivables as of the dates shown were categorized as follows: June 30, December 31, 2018 2017 Commercial real estate $ 1,235,158 $ 891,971 Residential real estate 699,482 577,123 Construction, land development, and other land 189,490 105,996 Commercial and industrial 1,026,371 522,254 Installment and other 12,758 4,182 Lease financing receivables 183,304 174,165 Total loans and leases 3,346,563 2,275,691 Net unamortized deferred fees and costs (1,442 ) (1,720 ) Initial direct costs 3,571 3,521 Allowance for loan and lease losses (19,687 ) (16,706 ) Net loans and leases $ 3,329,005 $ 2,260,786 June 30, December 31, 2018 2017 Lease financing receivables Net minimum lease payments $ 199,246 $ 188,986 Unguaranteed residual values 1,654 1,644 Unearned income (17,596 ) (16,465 ) Total lease financing receivables 183,304 174,165 Initial direct costs 3,571 3,521 Lease financial receivables before allowance for lease losses $ 186,875 $ 177,686
Summary of Minimum Annual Lease Payments for Lease Financing Receivables	The minimum Minimum Lease Payments 2018 $ 35,976 2019 64,945 2020 48,587 2021 30,122 2022 15,850 Thereafter 3,766 Total $ 199,246
Summary of Balances for Each Respective Loan and Lease Category	The following June 30, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 539,529 $ 162,621 $ 532,837 $ 1,234,987 Residential real estate 413,956 129,737 155,895 699,588 Construction, land development, and other land 134,004 4,860 49,752 188,616 Commercial and industrial 556,340 15,347 454,133 1,025,820 Installment and other 4,898 521 7,387 12,806 Lease financing receivables 156,017 — 30,858 186,875 Total loans and leases $ 1,804,744 $ 313,086 $ 1,230,862 $ 3,348,692 December 31, 2017 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 513,622 $ 166,712 $ 211,359 $ 891,693 Residential real estate 400,571 144,562 32,085 577,218 Construction, land development, and other land 97,638 5,946 1,845 105,429 Commercial and industrial 416,499 10,008 94,731 521,238 Installment and other 3,724 462 42 4,228 Lease financing receivables 141,329 — 36,357 177,686 Total loans and leases $ 1,573,383 $ 327,690 $ 376,419 $ 2,277,492
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 June 30, 2018 December 31, 2017 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 233,680 $ 162,621 $ 235,898 $ 166,712 Residential real estate 189,463 129,737 207,660 144,562 Construction, land development, and other land 12,955 4,860 13,270 5,946 Commercial and industrial 24,275 15,347 18,333 10,008 Installment and other 1,925 521 1,819 462 Total acquired impaired loans $ 462,298 $ 313,086 $ 476,980 $ 327,690
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 and six months ended June 30, 2018 and 2017: Three Months Ended Six Months Ended June 30, June 30, 2018 2017 2018 2017 Beginning balance $ 39,300 $ 34,744 $ 36,446 $ 36,868 Additions 3,566 — 3,566 — Accretion to interest income (5,871 ) (8,816 ) (11,562 ) (16,603 ) Reclassification from nonaccretable difference, net 4,311 11,691 12,856 17,354 Ending balance $ 41,306 $ 37,619 $ 41,306 $ 37,619
Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-Impaired Loans and Leases	The unpaid June 30, 2018 December 31, 2017 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 545,840 $ 532,837 $ 221,710 $ 211,359 Residential real estate 159,824 155,895 32,605 32,085 Construction, land development, and other land 51,270 49,752 1,926 1,845 Commercial and industrial 475,924 454,133 105,529 94,731 Installment and other 7,813 7,387 355 42 Lease financing receivables 32,524 30,858 37,476 36,357 Total acquired non-impaired loans and leases $ 1,273,195 $ 1,230,862 $ 399,601 $ 376,419

Allowance for Loan and Lease 34

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments (Tables)	6 Months Ended
	Jun. 30, 2018
Receivables [Abstract]
Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances	The following June 30, 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 $ 5,319 $ 1,564 $ 201 $ 7,763 $ 61 $ 2,732 $ 17,640 Provisions 1,336 84 131 1,956 1 448 3,956 Charge-offs (202 ) — — (1,596 ) (32 ) (555 ) (2,385 ) Recoveries — — — 246 — 230 476 Ending balance $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 Six months ended Beginning balance $ 4,794 $ 1,638 $ 222 $ 7,418 $ 41 $ 2,593 $ 16,706 Provisions 2,270 10 528 5,380 21 862 9,071 Charge-offs (611 ) — (418 ) (4,681 ) (32 ) (1,065 ) (6,807 ) Recoveries — — — 252 — 465 717 Ending balance $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 Ending balance: Individually evaluated for impairment $ 2,199 $ 127 $ — $ 2,555 $ 14 $ — $ 4,895 Collectively evaluated for impairment 2,752 1,171 310 4,940 13 2,855 12,041 Loans acquired with deteriorated credit quality 1,502 350 22 874 3 — 2,751 Total allowance for loan and lease losses $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 June 30, 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 $ 16,397 $ 2,273 $ — $ 14,889 $ 14 $ — $ 33,573 Collectively evaluated for impairment 1,055,969 567,578 183,756 995,584 12,271 186,875 3,002,033 Loans acquired with deteriorated credit quality 162,621 129,737 4,860 15,347 521 — 313,086 Total loans and leases $ 1,234,987 $ 699,588 $ 188,616 $ 1,025,820 $ 12,806 $ 186,875 $ 3,348,692 June 30, 2017 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 $ 2,047 $ 2,417 $ 417 $ 4,836 $ 331 $ 1,769 $ 11,817 Provisions (releases) 1,674 (453 ) (90 ) 1,637 13 734 3,515 Charge-offs (53 ) (129 ) — (784 ) — (767 ) (1,733 ) Recoveries — — — — — 370 370 Ending balance $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 Six months ended Beginning balance $ 1,945 $ 2,483 $ 742 $ 4,196 $ 334 $ 1,223 $ 10,923 Provisions (releases) 2,014 (452 ) (415 ) 2,492 10 1,757 5,406 Charge-offs (291 ) (196 ) — (999 ) — (1,537 ) (3,023 ) Recoveries — — — — — 663 663 Ending balance $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 Ending balance: Individually evaluated for impairment $ 396 $ 275 $ — $ 1,638 $ 326 $ — $ 2,635 Collectively evaluated for impairment 1,550 1,219 302 2,898 5 2,106 8,080 Loans acquired with deteriorated credit quality 1,722 341 25 1,153 13 — 3,254 Total allowance for loan and lease losses $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 June 30, 2017 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 $ 8,675 $ 1,271 $ 565 $ 3,081 $ 327 $ — $ 13,919 Collectively evaluated for impairment 632,353 421,096 86,240 452,693 2,633 171,161 1,766,176 Loans acquired with deteriorated credit quality 188,161 162,349 5,830 12,400 555 — 369,295 Total loans and leases $ 829,189 $ 584,716 $ 92,635 $ 468,174 $ 3,515 $ 171,161 $ 2,149,390
Summary of Recorded Investment, Unpaid Principal Balance, and Related Allowance for Loans and Leases Considered Impaired	The following and June 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 10,735 $ 12,211 $ — Residential real estate 1,935 1,910 — Commercial and industrial 4,391 5,438 — With an allowance recorded Commercial real estate 5,662 5,975 2,199 Residential real estate 338 334 127 Commercial and industrial 10,498 11,447 2,555 Installment and other 14 14 14 Total impaired loans $ 33,573 $ 37,329 $ 4,895 December 31, 2017 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 11,425 $ 12,936 $ — Residential real estate 2,075 2,046 — Commercial and industrial 5,470 6,774 — With an allowance recorded Commercial real estate 2,459 2,634 1,101 Residential real estate 354 351 158 Commercial and industrial 9,314 9,724 2,692 Installment and other 14 14 14 Total impaired loans $ 31,111 $ 34,479 $ 3,965
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 six months ended as follows: June 30, 2018 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 10,013 $ 436 Residential real estate 1,959 25 Commercial and industrial 7,283 99 With an allowance recorded Commercial real estate 4,587 183 Residential real estate 347 3 Commercial and industrial 8,784 233 Installment and other 14 979 Total impaired loans $ 32,987 $ 1,958 June 30, 2017 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 4,573 $ 199 Residential real estate 578 24 Construction, land development and other land 364 15 Commercial and industrial 1,119 43 With an allowance recorded Commercial real estate 667 — Residential real estate 240 3 Construction, land development and other land 87 — Commercial and industrial 2,047 263 Installment and other 159 9 Total impaired loans $ 9,834 $ 556
Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation	The following June 30, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 938,889 $ 533,937 $ 151,868 $ 840,647 $ 12,253 $ 184,166 $ 2,661,760 Watch 96,967 30,482 28,762 118,385 3 140 274,739 Special Mention 22,353 2,815 3,126 31,955 15 964 61,228 Substandard 14,157 2,617 — 19,486 14 1,289 37,563 Doubtful — — — — — 316 316 Loss — — — — — — — Total $ 1,072,366 $ 569,851 $ 183,756 $ 1,010,473 $ 12,285 $ 186,875 $ 3,035,606 December 31, 2017 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 638,066 $ 398,743 $ 73,935 $ 415,163 $ 3,732 $ 174,672 $ 1,704,311 Watch 58,217 29,165 22,380 67,024 20 190 176,996 Special Mention 14,645 2,251 3,168 13,535 — 1,293 34,892 Substandard 14,053 2,497 — 15,508 14 1,259 33,331 Doubtful — — — — — 272 272 Loss — — — — — — — Total $ 724,981 $ 432,656 $ 99,483 $ 511,230 $ 3,766 $ 177,686 $ 1,949,802
Summary of Contractual Delinquency Information	The following tables summarize contractual delinquency information for acquired non-impaired and originated loans and leases by category at June 30, 2018 and December 31, 2017: June 30, 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 $ 544 $ 636 $ — $ 11,534 $ 12,714 $ 1,059,652 $ 1,072,366 Residential real estate 492 15 — 1,619 2,126 567,725 569,851 Construction, land development, and other land — — — — — 183,756 183,756 Commercial and industrial 560 4,244 197 11,861 16,862 993,611 1,010,473 Installment and other 635 — — 14 649 11,636 12,285 Lease financing receivables 518 462 — 714 1,694 185,181 186,875 Total $ 2,749 $ 5,357 $ 197 $ 25,742 $ 34,045 $ 3,001,561 $ 3,035,606 December 31, 2017 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 $ 4,783 $ 968 $ — $ 8,459 $ 14,210 $ 710,771 $ 724,981 Residential real estate 148 — — 2,092 2,240 430,416 432,656 Construction, land development, and other land — — — — — 99,483 99,483 Commercial and industrial 6,667 967 — 4,348 11,982 499,248 511,230 Installment and other 18 — — 14 32 3,734 3,766 Lease financing receivables 997 638 — 851 2,486 175,200 177,686 Total $ 12,613 $ 2,573 $ — $ 15,764 $ 30,950 $ 1,918,852 $ 1,949,802

Servicing Assets (Tables)

Servicing Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Transfers And Servicing [Abstract]
Activity for Servicing Assets and Related Changes in Fair Value	Activity for the six months ended June 30, 2018 is Six Months Ended June 30, 2018 2017 Beginning balance $ 21,400 $ 21,091 Additions, net 4,191 2,948 Changes in fair value (4,004 ) (2,615 ) Ending balance $ 21,587 $ 21,424
Unpaid Principal Balances of Loans Serviced for Others	The unpaid as of June 30, 2018 and December 31, 2017: June 30, December 31, 2018 2017 Loan portfolios serviced for: SBA guaranteed loans 1,111,551 1,021,143 USDA guaranteed loans 84,019 91,758 Total $ 1,195,570 $ 1,112,901

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	6 Months Ended
	Jun. 30, 2018
Banking And Thrift [Abstract]
Change in Other Real Estate Owned	The following table presents the change in other real estate owned (“OREO”) for the six months ended June 30, 2018 and 2017. Six Months Ended June 30, 2018 2017 Beginning balance $ 10,626 $ 16,570 Net additions to OREO 1,067 2,490 Dispositions of OREO (5,231 ) (6,056 ) Valuation adjustments (60 ) (320 ) Ending balance $ 6,402 $ 12,684

Goodwill, Core Deposit Intang37

Goodwill, Core Deposit Intangible and Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets	The following table summarizes the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the six months ended June 30, 2018 and 2017: Six Months Ended June 30, 2018 2017 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Deposit Intangible Customer Relationship Intangible Beginning balance $ 54,562 $ 16,720 $ — $ 51,975 $ 19,776 $ — Additions 72,974 19,060 3,216 — — — Amortization or accretion — (1,863 ) (22 ) — (1,529 ) — Ending balance $ 127,536 $ 33,917 $ 3,194 $ 51,975 $ 18,247 $ — Accumulated amortization or accretion N/A $ 15,329 22 N/A $ 11,939 N/A Weighted average remaining amortization or accretion period N/A 7.1 Years 11.9 Years N/A 6.1 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 June 30, 2018: Estimated Amortization 2018 $ 3,644 2019 6,942 2020 6,478 2021 6,026 2022 5,578 Thereafter 8,472 Total $ 37,140

Deposits (Tables)

Deposits (Tables)	6 Months Ended
	Jun. 30, 2018
Deposits [Abstract]
Schedule of Deposits	The composition of deposits was as follows as of June 30, 2018 and December 31, 2017: June 30, December 31, 2018 2017 Non-interest bearing demand deposits $ 1,193,057 $ 760,887 Interest bearing checking accounts 287,330 186,611 Money market demand accounts 617,108 349,862 Other savings 487,130 437,212 Time deposits (below $250,000) 879,643 627,255 Time deposits ($250,000 and above) 180,609 81,502 Total deposits $ 3,644,877 $ 2,443,329

Federal Home Loan Bank Advanc39

Federal Home Loan Bank Advances (Tables)	6 Months Ended
	Jun. 30, 2018
Federal Home Loan Banks [Abstract]
Summary of FHLB Advances	The following June 30, December 31, 2018 2017 Federal Home Loan Bank advances $ 420,000 $ 361,506 Weighted average cost 2.01 % 1.49 %

Other Borrowings (Tables)

Other Borrowings (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Summary of Other Borrowings	The following is a summary of the Company’s other borrowings as of June 30, 2018 and December 31, 2017: June 30, December 31, 2018 2017 Securities sold under agreements to repurchase $ 24,653 $ 31,187 Line of credit — — Total $ 24,653 $ 31,187
Summary of Short-term Credit Lines Available for Use	The following June 30, December 31, 2018 2017 Federal Reserve Bank of Chicago discount window line $ 329,627 $ 144,248 Available federal funds lines 55,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures (Tables)	6 Months Ended
	Jun. 30, 2018
Debt Disclosure [Abstract]
Junior Subordinated Debentures by Issuance	At June 30, 2018 and December 31, 2017, the Name of Trust Aggregate Principal Amount June 30, 2018 Aggregate Principal Amount December 31, 2017 Stated Maturity Contractual Rate at June 30, 2018 Interest Rate Spread Metropolitan $ 35,000 $ 35,000 March 5.12 % 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 — March 15, 2035 4.12 % Three-month LIBOR + 1.78% Total liability, at par 46,500 36,500 Discount (10,048 ) (8,853 ) Total liability, at carrying value $ 36,452 $ 27,647

Commitments and Contingent Li42

Commitments and Contingent Liabilities (Tables)	6 Months Ended
	Jun. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Summary of Minimum Annual Rental Commitments for Operating Leases	The minimum Minimum Commitments 2018 $ 1,823 2019 3,183 2020 2,652 2021 2,321 2022 1,355 Thereafter 2,870 Total $ 14,204
Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments	The following June 30, 2018 and December 31, 2017 June 30, December 31, 2018 2017 Fixed Rate Variable Rate Fixed Rate Variable Rate Commitments to extend credit $ 78,076 $ 947,386 $ 55,924 $ 467,429 Standby letters of credit 2,360 26,369 1,226 3,337 Total $ 80,436 $ 973,755 $ 57,150 $ 470,766

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 44,423 $ 44,423 $ — $ — U.S. Government agencies 145,009 — 145,009 — Obligations of states, municipalities, and political subdivisions 59,293 — 58,604 689 Residential mortgage-backed securities Agency 299,534 — 299,534 — Non-agency 61,963 — 61,963 — Commercial mortgage-backed securities Agency 73,253 — 73,253 — Non-agency 30,104 — 30,104 — Corporate securities 37,590 — 37,590 — Other securities 6,656 2,844 3,121 691 Servicing assets 21,587 — — 21,587 Derivative assets 13,063 — 13,063 — Financial liabilities Derivative liabilities 2,869 — 2,867 2 Fair Value Measurements Using December 31, 2017 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 14,863 $ 14,863 $ — $ — U.S. Government agencies 52,958 — 52,958 — Obligations of states, municipalities, and political subdivisions 33,170 — 32,795 375 Residential mortgage-backed securities Agency 307,457 — 307,457 — Non-agency 39,514 — 39,514 — Commercial mortgage-backed securities Agency 69,043 — 69,043 — Non-agency 30,971 — 30,971 — Corporate securities 29,976 — 29,976 — Other securities 5,284 1,921 2,686 677 Servicing assets 21,400 — — 21,400 Derivative assets 5,981 — 5,981 — Financial liabilities Derivative liabilities 994 — 994 —
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): Six Months Ended June 30, 2018 2017 2018 2017 Investment Securities Servicing Assets Balance, beginning of period $ 1,052 $ 1,080 $ 21,400 $ 21,091 Acquired assets at fair value 314 — — — Additions, net — — 4,191 2,948 Amortization 3 2 — — Change in unrealized gain 11 (5 ) — — Change in fair value — — (4,004 ) (2,615 ) Balance, end of period $ 1,380 $ 1,077 $ 21,587 $ 21,424
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 1.3%—2.4% 1.8 % Decrease Single issuer trust preferred Discounted cash flow Probability of default 4.9%—7.0% 6.1 % Decrease Servicing assets Discounted cash flow Prepayment speeds 4.6%—23.0% 10.0 % Decrease Discount rate 6.6%—22.0% 14.1 % Decrease Expected weighted average loan life 0.2—7.4 years 5.3 years Increase
Summary of Company's Assets Measured at Fair Value on a Non-Recurring Basis	The following tables Fair Value Measurements Using June 30, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 14,198 $ — $ — $ 14,198 Residential real estate 2,146 — — 2,146 Construction, land development, and other land — — — — Commercial and industrial 12,334 — — 12,334 Installment and other — — — — Assets held for sale 11,428 — — 11,428 Other real estate owned 6,402 — — 6,402 Fair Value Measurements Using December 31, 2017 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 12,783 $ — $ — $ 12,783 Residential real estate 2,271 — — 2,271 Construction, land development, and other land — — — — Commercial and industrial 12,092 — — 12,092 Installment and other — — — — Assets held for sale 9,779 — — 9,779 Other real estate owned 10,626 — — 10,626
Summary of the Valuation Technique, Unobservable Inputs and Qualitative Information About the Company's Assets and Liabilities	The following Financial Instruments Valuation Technique Unobservable Inputs Range of Inputs Impact to Valuation from an Increased or Higher Input Value Impaired loans (excluding acquired impaired loans) Appraisals Appraisal adjustments, sales costs and other discount adjustments for market conditions 6% - 10% Decrease Assets held for sale List price, contract price Sales costs and other discount adjustments for market conditions 7% Decrease Other real estate owned Appraisals Appraisal adjustments, sales costs and other discount adjustments for market conditions 7% - 20% Decrease
Estimated Fair Values of Financial Instruments	The estimated June 30, December 31, Fair Value 2018 2017 Hierarchy Level Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets Cash and due from banks 1 $ 25,299 $ 25,299 $ 19,404 $ 19,404 Interest bearing deposits with other banks 2 127,417 127,417 38,945 38,945 Securities held-to-maturity 2 106,613 104,411 117,163 117,277 Other restricted stock 2 18,977 18,977 16,343 16,343 Loans held for sale 3 5,822 6,494 5,212 5,851 Loans and lease receivables, net 3 3,329,005 3,288,358 2,260,786 2,240,235 Accrued interest receivable 3 10,670 10,670 7,670 7,670 Financial liabilities Non-interest bearing deposits 2 1,193,057 1,193,057 760,887 760,887 Interest bearing deposits 2 2,451,820 2,447,100 1,682,442 1,678,535 Accrued interest payable 2 2,562 2,562 1,306 1,306 Line of credit 2 — — — — Federal Home Loan Bank advances 2 420,000 420,000 361,506 361,500 Securities sold under repurchase agreement 2 24,653 24,653 31,187 31,187 Junior subordinated debentures 3 36,452 42,475 27,647 33,907

Derivative Instruments and He44

Derivative Instruments and Hedge Activities (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, 2018 and December 31, 2017: June 30, 2018 December 31, 2017 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 $ 10,238 $ — $ 250,000 $ 5,030 $ 38 Derivatives not designated as hedging instruments Other interest rate swaps 214,015 2,825 2,867 94,726 951 956 Other credit derivatives 1,250 — 2 — — — Total derivatives $ 465,265 $ 13,063 $ 2,869 $ 344,726 $ 5,981 $ 994
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 six months ended: June 30, 2018 June 30, 2017 Amount of Gain Recognized in OCI (Effective Portion) Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income (Ineffective Portion) Amount of Gain (Loss) Recognized in OCI (Effective Portion) Amount of Loss Reclassified from OCI to Income as an Increase to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income (Ineffective Portion) Interest rate swaps $ 5,632 $ 435 $ — $ (1,425 ) $ (267 ) $ —
Summary of Other Interest Rate Swaps	The following table reflects other interest rate swaps as of June 30, 2018 Notional amounts $ 214,015 Derivative assets fair value 2,825 Derivative liabilities fair value 2,867 Weighted average pay rates 4.66 % Weighted average receive rates 4.04 % Weighted average maturity 5.8 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: June 30, 2018 December 31, 2017 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 13,063 $ 2,869 $ 5,981 $ 994 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 13,063 $ 2,869 $ 5,981 $ 994 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (1,091 ) (1,091 ) (232 ) (232 ) Collateral posted (11,972 ) (1,775 ) (5,371 ) (745 ) Net credit exposure $ — $ 3 $ 378 $ 17 As of June 30, 2018, the counterparties posted collateral of $12.1 million, which resulted in no excess collateral with the Company. For purposes of this disclosure, the amount of posted collateral by the counterparties is limited to the amount offsetting the derivatives asset.
Cash Flow Hedges
Summary of Cash Flow Hedges	The following table reflects the cash flow hedges as of June 30, 2018: Notional amounts $ 250,000 Derivative assets fair value 10,238 Derivative liabilities fair value — Weighted average pay rates 1.67 % Weighted average receive rates 1.63 % Weighted average maturity 4.2 years

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 and 2017: Six Months Ended June 30, 2018 2017 Total share-based compensation - stock options $ 450 $ 571 Income tax benefit 125 227 Unrecognized compensation expense 271 1,181 Weighted-average amortization period remaining 1.3 years 1.4 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 six months ended June 30, 2018 and 2017: Six Months Ended June 30, 2018 2017 Total share-based compensation - restricted stock $ 326 $ — Income tax benefit 91 — Unrecognized compensation expense 3,691 — Weighted-average amortization period remaining 3.3 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 six months ended June 30, 2018: Omnibus Plan Number of Shares Weighted Average Grant Date Fair Value Beginning balance, January 1, 2018 70,398 $ 20.31 Granted 126,157 $ 22.38 Vested — $ — Forfeited (2,100 ) $ 20.84 Ending balance outstanding at June 30, 2018 194,455 $ 21.65
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. The fair values of options under the BYB Plan were determined using the following assumptions as of the grant dates: Time Options Grants 2016 2015 Risk-free interest rate 1.34% - 1.40% 1.68% - 1.85% Expected term (years) 5.2 - 5.6 5.7 - 6.3 Expected stock price volatility 20.39 % 16.18%-16.55% Expected dividend yield 0.00 % 0.00 % Weighted average grant date fair value $ 3.55 $ 2.25 Performance Options Grants 2016 2015 Risk-free interest rate Implied forward rates Implied forward rates Expected term (years) Variable Variable Expected stock price volatility 20.34% - 20.39% 16.18%-16.55% Expected dividend yield 0.00 % 0.00 % Weighted average grant date fair value $ 3.75 $ 1.65
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 six months ended June 30, 2018: BYB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2018 1,783,020 $ 11.91 $ 19,718 7.6 Granted — Expired — Exercised (94,750 ) 11.98 $ 988 Forfeited (5,000 ) 16.25 Ending balance outstanding at June 30, 2018 1,683,270 $ 11.89 $ 17,583 7.1 Exercisable at June 30, 2018 1,516,670 $ 11.42 $ 16,568 7.0
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 six months ended June 30, 2018: FEB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2018 — $ — $ — — Granted 680,787 11.26 $ 7,544 Expired — Exercised — Forfeited — Ending balance outstanding at June 30, 2018 680,787 $ 11.26 $ 7,544 5.3 Exercisable at June 30, 2018 680,787 $ 11.26 $ 7,544 5.3

Earnings per Share (Tables)

Earnings per Share (Tables)	6 Months Ended
	Jun. 30, 2018
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 June 30, Six Months Ended June 30, 2018 2017 2018 2017 Net income $ 2,768 $ 6,146 $ 9,536 $ 12,706 Less: Dividends on preferred shares 198 10,697 391 10,886 Net income available (loss attributable) to common stockholders $ 2,570 $ (4,551 ) $ 9,145 $ 1,820 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 31,614,973 24,667,587 30,459,495 24,642,287 Incremental shares 953,423 — 988,825 464,600 Weighted-average common stock outstanding (dilutive) 32,568,396 24,667,587 31,448,320 25,106,887 Basic earnings per common share $ 0.08 $ (0.18 ) $ 0.30 $ 0.07 Diluted earnings per common share $ 0.08 $ (0.18 ) $ 0.29 $ 0.07

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	6 Months Ended
	Jun. 30, 2018
Equity [Abstract]
Summary of Preferred and Common Stock	A summary of the Company’s preferred and common stock at June 30, 2018 and December 31, 2017 is as follows: June 30, December 31, 2018 2017 Series B 7.5% fixed 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 36,218,955 29,317,298 Shares outstanding 36,218,955 29,317,298

Consolidated Statements of Ch48

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Tables)	6 Months Ended
	Jun. 30, 2018
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 six months ended June 30, 2018 and June 30, 2017: (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, 2017 $ 2,233 $ (9,501 ) $ (7,268 ) Other comprehensive (loss) income, net of tax (693 ) 1,549 856 Balance, June 30, 2017 $ 1,540 $ (7,952 ) $ (6,412 ) 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 3,750 (8,235 ) (4,485 ) Balance, June 30, 2018 $ 7,350 $ (17,685 ) $ (10,335 )

Basis of Presentation - Schedul

Basis of Presentation - Schedule of Aforementioned Revisions to Consolidated Statements of Financial Condition (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Goodwill	$ 127,536	$ 54,562	$ 51,975	$ 51,975
Deferred tax assets, net	48,936	47,376
Total assets	$ 4,805,280	3,366,130
As Reported
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Goodwill		51,975
Deferred tax assets, net		49,963
Total assets		3,366,130
Adjustment
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Goodwill		2,587
Deferred tax assets, net		$ (2,587)

Recently Issued Accounting Pr50

Recently Issued Accounting Pronouncements - Additional Information (Details)	6 Months Ended
	Jun. 30, 2018USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain income tax effects from accumulated other comprehensive income	$ (763,000)
ASU 2018-02
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain income tax effects from accumulated other comprehensive income	$ 763,000

Acquisition of a Business - Add

Acquisition of a Business - Additional Information (Details) - USD ($)	May 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 127,536,000	$ 54,562,000	$ 51,975,000	$ 51,975,000
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	$ 72,974,000
First Evanston Bancorp, Inc. | Non-interest Expense
Business Acquisition [Line Items]
Acquisition advisory expenses		$ 1,600,000
Core system conversion expenses		$ 9,000,000

Acquisition of a Business - Sum

Acquisition of a Business - Summary of Preliminary Estimates of fair Values of Assets and Liabilities Assumed as of Acquisition Date (Details) - USD ($) $ in Thousands	May 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Consideration paid
Goodwill		$ 127,536	$ 54,562	$ 51,975	$ 51,975
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	16,778
Other intangible assets	22,276
Deferred tax assets, net	2,055
Other assets	8,845
Total assets acquired	1,142,766
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	106,157
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	$ 72,974

Acquisition of a Business - S53

Acquisition of a Business - Summary of Estimates 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 - S54

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	$ 889,115
Gross contractual amounts receivable	1,055,502
Estimate of contractual cash flows not expected to be collected	36,544	[1]
Estimate of contractual cash flows expected to be collected	$ 1,018,958
[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 - S55

Acquisition of a Business - Summary of Unaudited Pro Forma Information for Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Business Combinations [Abstract]
Total revenues (net interest income and non-interest income)	$ 61,775	$ 55,995	$ 119,828	$ 111,641
Net income	$ 10,709	$ 9,075	$ 21,166	$ 19,073
Earnings (loss) per share—basic	$ 0.29	$ (0.05)	$ 0.58	$ 0.26
Earnings (loss) per share—diluted	$ 0.28	$ (0.05)	$ 0.56	$ 0.26

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 779,168	$ 593,167
Available-for-sale Securities, Gross Unrealized Gains	2,615	2,486
Available-for-sale Securities, Gross Unrealized Losses	(23,958)	(12,417)
Available-for-sale Securities, Fair Value	757,825	583,236
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	44,683	14,999
Available-for-sale Securities, Gross Unrealized Gains	4
Available-for-sale Securities, Gross Unrealized Losses	(264)	(136)
Available-for-sale Securities, Fair Value	44,423	14,863
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	146,887	54,248
Available-for-sale Securities, Gross Unrealized Gains	26
Available-for-sale Securities, Gross Unrealized Losses	(1,904)	(1,290)
Available-for-sale Securities, Fair Value	145,009	52,958
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	59,995	33,405
Available-for-sale Securities, Gross Unrealized Gains	110	100
Available-for-sale Securities, Gross Unrealized Losses	(812)	(335)
Available-for-sale Securities, Fair Value	59,293	33,170
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	313,823	315,103
Available-for-sale Securities, Gross Unrealized Losses	(14,289)	(7,646)
Available-for-sale Securities, Fair Value	299,534	307,457
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	63,519	39,485
Available-for-sale Securities, Gross Unrealized Gains		104
Available-for-sale Securities, Gross Unrealized Losses	(1,556)	(75)
Available-for-sale Securities, Fair Value	61,963	39,514
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	76,332	70,964
Available-for-sale Securities, Gross Unrealized Gains	72	45
Available-for-sale Securities, Gross Unrealized Losses	(3,151)	(1,966)
Available-for-sale Securities, Fair Value	73,253	69,043
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	31,612	31,763
Available-for-sale Securities, Gross Unrealized Losses	(1,508)	(792)
Available-for-sale Securities, Fair Value	30,104	30,971
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	37,707	29,573
Available-for-sale Securities, Gross Unrealized Gains	227	507
Available-for-sale Securities, Gross Unrealized Losses	(344)	(104)
Available-for-sale Securities, Fair Value	37,590	29,976
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	4,610	3,627
Available-for-sale Securities, Gross Unrealized Gains	2,176	1,730
Available-for-sale Securities, Gross Unrealized Losses	(130)	(73)
Available-for-sale Securities, Fair Value	$ 6,656	$ 5,284

Securities - Summary of Amort57

Securities - Summary of Amortized Cost and Fair Values of Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	$ 106,613	$ 117,163
Held-to-maturity Securities, Gross Unrealized Gains	28	450
Held-to-maturity Securities, Gross Unrealized Losses	(2,230)	(336)
Securities held-to-maturity, fair value	104,411	117,277
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	23,934	24,030
Held-to-maturity Securities, Gross Unrealized Gains	28	197
Held-to-maturity Securities, Gross Unrealized Losses	(373)	(82)
Securities held-to-maturity, fair value	23,589	24,145
Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	45,422	53,731
Held-to-maturity Securities, Gross Unrealized Gains		79
Held-to-maturity Securities, Gross Unrealized Losses	(843)	(203)
Securities held-to-maturity, fair value	44,579	53,607
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	37,257	39,402
Held-to-maturity Securities, Gross Unrealized Gains		174
Held-to-maturity Securities, Gross Unrealized Losses	(1,014)	(51)
Securities held-to-maturity, fair value	$ 36,243	$ 39,525

Securities - Additional Informa

Securities - Additional Information (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018USD ($)Security	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Security	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Schedule Of Investments [Line Items]
Trading securities	$ 0		$ 0		$ 0
Net gains or (losses) reclassified from accumulated other comprehensive income (loss) into earnings	4,000	$ 0	4,000	$ 8,000
Carrying amount of securities pledged as collateral	$ 221,400,000		$ 221,400,000		$ 262,500,000
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%		10.00%
Federal Home Loan Bank Advances
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral	$ 0		$ 0		$ 128,400,000
Public Fund Deposits
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral	186,500,000		186,500,000		99,300,000
Customer Repurchase Agreements
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral	$ 34,900,000		$ 34,900,000		$ 34,800,000
Available-for-sale Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security	170		170
Held-to-maturity Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security	54		54

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	6 Months Ended	12 Months Ended
	Jun. 30, 2018USD ($)Security	Dec. 31, 2017USD ($)Security
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	170	101
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 223,509	$ 39,896
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(2,865)	(407)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	431,189	455,688
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(21,093)	(12,010)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	654,698	495,584
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (23,958)	$ (12,417)
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	18	5
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 24,695	$ 4,998
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(76)	(2)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	9,813	9,865
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(188)	(134)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	34,508	14,863
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (264)	$ (136)
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	36	9
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 62,216	$ 992
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(92)	(7)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	51,471	51,966
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(1,812)	(1,283)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	113,687	52,958
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,904)	$ (1,290)
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	40	29
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 24,271	$ 16,059
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(564)	(137)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,396	4,453
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(248)	(198)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	28,667	20,512
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (812)	$ (335)
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	44	41
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 30,404	$ 15,441
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(604)	(181)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	269,131	292,016
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(13,685)	(7,465)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	299,535	307,457
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (14,289)	$ (7,646)
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	7	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 57,749
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1,350)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,213	$ 4,565
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(206)	(75)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	61,962	4,565
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,556)	$ (75)
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	8	7
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 7,228
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(46)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	54,473	$ 57,442
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(3,105)	(1,966)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	61,701	57,442
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (3,151)	$ (1,966)
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	$ 30,104	$ 30,971
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(1,508)	(792)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	30,104	30,971
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,508)	$ (792)
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	11	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 16,946	$ 2,406
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(133)	(80)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,744	2,489
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(211)	(24)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	21,690	4,895
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (344)	$ (104)
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	1	1
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	$ 2,844	$ 1,921
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(130)	(73)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	2,844	1,921
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (130)	$ (73)

Securities - Summary of Gross60

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	6 Months Ended	12 Months Ended
	Jun. 30, 2018USD ($)Security	Dec. 31, 2017USD ($)Security
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Continuous Unrealized Loss Position, Number of Securities | Security	54	28
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 88,094	$ 42,211
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1,732)	(155)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	12,432	13,865
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(498)	(181)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	100,526	56,076
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (2,230)	$ (336)
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	27	12
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 18,166	$ 7,409
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(327)	(38)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,538	1,548
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(46)	(44)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	19,704	8,957
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (373)	$ (82)
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	20	13
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 37,755	$ 24,344
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(558)	(107)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	6,824	7,935
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(285)	(96)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	44,579	32,279
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (843)	$ (203)
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	3
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 32,173	$ 10,458
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(847)	(10)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,070	4,382
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(167)	(41)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	36,243	14,840
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,014)	$ (51)

Securities - Summary of Proceed

Securities - Summary of Proceeds From Sales of Securities Available-for-sale and Associated Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017
Available For Sale Securities Gross Realized Gain Loss [Abstract]
Proceeds	$ 544	$ 544	$ 8
Gross gains	$ 4	$ 4	$ 8

Securities - Schedule of Amorti

Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Due in one year or less, Amortized Cost	$ 40,479
Available-for-sale Securities, Due from one to five years, Amortized Cost	187,741
Available-for-sale Securities, Due from five to ten years, Amortized Cost	49,553
Available-for-sale Securities, Due after ten years, Amortized Cost	12,036
Available-for-sale Securities, Amortized Cost	779,168	$ 593,167
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Due from one to five years, Amortized Cost	4,060
Held-to-maturity Securities, Due from five to ten years, Amortized Cost	11,646
Held-to-maturity Securities, Due after ten years, Amortized Cost	8,228
Held-to-maturity Securities, Amortized Cost	106,613	117,163
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Due in one year or less, Fair Value	40,475
Available-for-sale Securities, Due from one to five years, Fair Value	186,169
Available-for-sale Securities, Due from five to ten years, Fair Value	48,404
Available-for-sale Securities, Due after ten years, Fair Value	11,958
Total	757,825	583,236
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Due from one to five years, Fair Value	4,031
Held-to-maturity Securities, Due from five to ten years, Fair Value	11,442
Held-to-maturity Securities, Due after ten years, Fair Value	8,116
Total	104,411	117,277
Mortgage-Backed Securities
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Not due at single maturity, Amortized Cost	485,286
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Mortgage-backed securities, Amortized Cost	82,679
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	464,854
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Mortgage-backed securities, Fair Value	80,822
Other Securities With No Defined Maturity
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Not due at single maturity, Amortized Cost	4,073
Available-for-sale Securities, Amortized Cost	4,610	3,627
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	5,965
Total	$ 6,656	$ 5,284

Loan and Lease Receivables - Sc

Loan and Lease Receivables - Schedule of Outstanding Loan and Lease Receivables (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,346,563		$ 2,275,691
Net unamortized deferred fees and costs	(1,442)		(1,720)
Initial direct costs	3,571		3,521
Allowance for loan and lease losses	(19,687)	$ (17,640)	(16,706)	$ (13,969)	$ (11,817)	$ (10,923)
Net loans and leases	3,329,005		2,260,786
Lease financing receivables
Net minimum lease payments	199,246		188,986
Unguaranteed residual values	1,654		1,644
Unearned income	(17,596)		(16,465)
Total lease financing receivables	183,304		174,165
Initial direct costs	3,571		3,521
Lease financial receivables before allowance for lease losses	186,875		177,686
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,235,158		891,971
Allowance for loan and lease losses	(6,453)	(5,319)	(4,794)	(3,668)	(2,047)	(1,945)
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	699,482		577,123
Allowance for loan and lease losses	(1,648)	(1,564)	(1,638)	(1,835)	(2,417)	(2,483)
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	189,490		105,996
Allowance for loan and lease losses	(332)	(201)	(222)	(327)	(417)	(742)
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,026,371		522,254
Allowance for loan and lease losses	(8,369)	(7,763)	(7,418)	(5,689)	(4,836)	(4,196)
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,758		4,182
Allowance for loan and lease losses	(30)	(61)	(41)	(344)	(331)	(334)
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	183,304		174,165
Allowance for loan and lease losses	$ (2,855)	$ (2,732)	$ (2,593)	$ (2,106)	$ (1,769)	$ (1,223)

Loan and Lease Receivables - Ad

Loan and Lease Receivables - Additional Information (Details) - USD ($)	Jun. 30, 2018	May 31, 2018	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,346,563,000			$ 2,275,691,000
Loans held for sale pledged as security for borrowings	1,400,000,000			516,900,000
Allowance for loan and lease losses	19,687,000		$ 17,640,000	16,706,000	$ 13,969,000	$ 11,817,000	$ 10,923,000
Acquired Impaired Loans
Accounts Notes And Loans Receivable [Line Items]
Loans acquired	0	$ 25,025,000		0
Allowance for loan and lease losses	2,800,000			3,900,000
Acquired Non-Impaired Loans and Leases | First Evanston
Accounts Notes And Loans Receivable [Line Items]
Loans acquired	889,100,000
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,758,000			4,182,000
Overdraft deposits reclassified as loans	1,300,000			617,000
Allowance for loan and lease losses	30,000		$ 61,000	41,000	$ 344,000	$ 331,000	$ 334,000
U.S. Government Guaranteed Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 95,100,000			$ 77,000,000

Loan and Lease Receivables - Su

Loan and Lease Receivables - Summary of Minimum Annual Lease Payments for Lease Financing Receivables (Details) $ in Thousands	Jun. 30, 2018USD ($)
Receivables [Abstract]
2,018	$ 35,976
2,019	64,945
2,020	48,587
2,021	30,122
2,022	15,850
Thereafter	3,766
Total	$ 199,246

Loan and Lease Receivables - 66

Loan and Lease Receivables - Summary of Balances for Each Respective Loan and Lease Category (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,348,692	$ 2,277,492	$ 2,149,390
Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,804,744	1,573,383
Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	313,086	327,690
Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,230,862	376,419
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,234,987	891,693	829,189
Commercial Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	539,529	513,622
Commercial Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	162,621	166,712
Commercial Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	532,837	211,359
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	699,588	577,218	584,716
Residential Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	413,956	400,571
Residential Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	129,737	144,562
Residential Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	155,895	32,085
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	188,616	105,429	92,635
Construction, Land Development, and Other Land | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	134,004	97,638
Construction, Land Development, and Other Land | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	4,860	5,946
Construction, Land Development, and Other Land | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	49,752	1,845
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,025,820	521,238	468,174
Commercial and Industrial | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	556,340	416,499
Commercial and Industrial | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	15,347	10,008
Commercial and Industrial | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	454,133	94,731
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,806	4,228	3,515
Installment and Other | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	4,898	3,724
Installment and Other | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	521	462
Installment and Other | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	7,387	42
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	186,875	177,686	$ 171,161
Lease Financing Receivables | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	156,017	141,329
Lease Financing Receivables | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 30,858	$ 36,357

Loan and Lease Receivables - Es

Loan and Lease Receivables - Estimated Fair Value of Impaired Loans Acquired at Acquisition (Details) - Acquired Impaired Loans - USD ($)	Jun. 30, 2018	May 31, 2018	Dec. 31, 2017
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	$ 25,025,000	$ 0

Loan and Lease Receivables - 68

Loan and Lease Receivables - Summary of Outstanding Balance and Carrying Amount of All Acquired Impaired Loans (Details) - Acquired Impaired Loans - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	$ 462,298	$ 476,980
Carrying Value	313,086	327,690
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	233,680	235,898
Carrying Value	162,621	166,712
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	189,463	207,660
Carrying Value	129,737	144,562
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	12,955	13,270
Carrying Value	4,860	5,946
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	24,275	18,333
Carrying Value	15,347	10,008
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	1,925	1,819
Carrying Value	$ 521	$ 462

Loan and Lease Receivables - 69

Loan and Lease Receivables - Summary of Changes in Accretable Yield for Acquired Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Receivables [Abstract]
Beginning balance	$ 39,300	$ 34,744	$ 36,446	$ 36,868
Additions	3,566		3,566
Accretion to interest income	(5,871)	(8,816)	(11,562)	(16,603)
Reclassification from nonaccretable difference, net	4,311	11,691	12,856	17,354
Ending balance	$ 41,306	$ 37,619	$ 41,306	$ 37,619

Loan and Lease Receivables - 70

Loan and Lease Receivables - Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-impaired Loans and Leases (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	$ 3,348,692	$ 2,277,492	$ 2,149,390
Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	1,273,195	399,601
Loans and leases	1,230,862	376,419
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,234,987	891,693	829,189
Commercial Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	545,840	221,710
Loans and leases	532,837	211,359
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	699,588	577,218	584,716
Residential Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	159,824	32,605
Loans and leases	155,895	32,085
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	188,616	105,429	92,635
Construction, Land Development, and Other Land | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	51,270	1,926
Loans and leases	49,752	1,845
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,025,820	521,238	468,174
Commercial and Industrial | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	475,924	105,529
Loans and leases	454,133	94,731
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	12,806	4,228	3,515
Installment and Other | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	7,813	355
Loans and leases	7,387	42
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	186,875	177,686	$ 171,161
Lease Financing Receivables | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	32,524	37,476
Loans and leases	$ 30,858	$ 36,357

Allowance for Loan and Lease 71

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Allowance for loan and lease losses
Beginning balance	$ 17,640	$ 11,817	$ 16,706	$ 10,923
Provisions (releases)	3,956	3,515	9,071	5,406
Charge-offs	(2,385)	(1,733)	(6,807)	(3,023)
Recoveries	476	370	717	663
Ending balance	19,687	13,969	19,687	13,969
Ending balance:
Individually evaluated for impairment					$ 4,895		$ 2,635
Collectively evaluated for impairment					12,041		8,080
Allowance for loan and lease losses	19,687	11,817	19,687	13,969	19,687	$ 16,706	13,969
Loans and leases ending balance:
Individually evaluated for impairment					33,573		13,919
Collectively evaluated for impairment					3,002,033		1,766,176
Total loans and leases					3,348,692	2,277,492	2,149,390
Receivables Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2,751		3,254
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					313,086		369,295
Commercial Real Estate
Allowance for loan and lease losses
Beginning balance	5,319	2,047	4,794	1,945
Provisions (releases)	1,336	1,674	2,270	2,014
Charge-offs	(202)	(53)	(611)	(291)
Ending balance	6,453	3,668	6,453	3,668
Ending balance:
Individually evaluated for impairment					2,199		396
Collectively evaluated for impairment					2,752		1,550
Allowance for loan and lease losses	5,319	2,047	6,453	3,668	6,453	4,794	3,668
Loans and leases ending balance:
Individually evaluated for impairment					16,397		8,675
Collectively evaluated for impairment					1,055,969		632,353
Total loans and leases					1,234,987	891,693	829,189
Commercial Real Estate | Receivables Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					1,502		1,722
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					162,621		188,161
Residential Real Estate
Allowance for loan and lease losses
Beginning balance	1,564	2,417	1,638	2,483
Provisions (releases)	84	(453)	10	(452)
Charge-offs		(129)		(196)
Ending balance	1,648	1,835	1,648	1,835
Ending balance:
Individually evaluated for impairment					127		275
Collectively evaluated for impairment					1,171		1,219
Allowance for loan and lease losses	1,564	2,417	1,648	1,835	1,648	1,638	1,835
Loans and leases ending balance:
Individually evaluated for impairment					2,273		1,271
Collectively evaluated for impairment					567,578		421,096
Total loans and leases					699,588	577,218	584,716
Residential Real Estate | Receivables Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					350		341
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					129,737		162,349
Construction, Land Development, and Other Land
Allowance for loan and lease losses
Beginning balance	201	417	222	742
Provisions (releases)	131	(90)	528	(415)
Charge-offs			(418)
Ending balance	332	327	332	327
Ending balance:
Collectively evaluated for impairment					310		302
Allowance for loan and lease losses	201	417	332	327	332	222	327
Loans and leases ending balance:
Individually evaluated for impairment							565
Collectively evaluated for impairment					183,756		86,240
Total loans and leases					188,616	105,429	92,635
Construction, Land Development, and Other Land | Receivables Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					22		25
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					4,860		5,830
Commercial and Industrial
Allowance for loan and lease losses
Beginning balance	7,763	4,836	7,418	4,196
Provisions (releases)	1,956	1,637	5,380	2,492
Charge-offs	(1,596)	(784)	(4,681)	(999)
Recoveries	246		252
Ending balance	8,369	5,689	8,369	5,689
Ending balance:
Individually evaluated for impairment					2,555		1,638
Collectively evaluated for impairment					4,940		2,898
Allowance for loan and lease losses	7,763	4,836	8,369	5,689	8,369	7,418	5,689
Loans and leases ending balance:
Individually evaluated for impairment					14,889		3,081
Collectively evaluated for impairment					995,584		452,693
Total loans and leases					1,025,820	521,238	468,174
Commercial and Industrial | Receivables Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					874		1,153
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					15,347		12,400
Installment and Other
Allowance for loan and lease losses
Beginning balance	61	331	41	334
Provisions (releases)	1	13	21	10
Charge-offs	(32)		(32)
Ending balance	30	344	30	344
Ending balance:
Individually evaluated for impairment					14		326
Collectively evaluated for impairment					13		5
Allowance for loan and lease losses	61	331	30	344	30	41	344
Loans and leases ending balance:
Individually evaluated for impairment					14		327
Collectively evaluated for impairment					12,271		2,633
Total loans and leases					12,806	4,228	3,515
Installment and Other | Receivables Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					3		13
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					521		555
Lease Financing Receivables
Allowance for loan and lease losses
Beginning balance	2,732	1,769	2,593	1,223
Provisions (releases)	448	734	862	1,757
Charge-offs	(555)	(767)	(1,065)	(1,537)
Recoveries	230	370	465	663
Ending balance	2,855	2,106	2,855	2,106
Ending balance:
Collectively evaluated for impairment					2,855		2,106
Allowance for loan and lease losses	$ 2,732	$ 1,769	$ 2,855	$ 2,106	2,855	2,593	2,106
Loans and leases ending balance:
Collectively evaluated for impairment					186,875		171,161
Total loans and leases					$ 186,875	$ 177,686	$ 171,161

Allowance for Loan and Lease 72

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Additional Information (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2018USD ($)Loan	Jun. 30, 2017USD ($)	Jun. 30, 2018USD ($)Loan	Jun. 30, 2017USD ($)	Dec. 31, 2017USD ($)
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 2,000,000	$ 2,200,000	$ 3,000,000	$ 3,000,000
Recorded investment in troubled debt restructurings	7,000,000		7,000,000		$ 2,600,000
Specific allowance allocated for loans	1,100,000		1,100,000		357,000
Commitments outstanding on troubled debt restructurings	500,000		500,000		0
Charge-offs or permanent reductions of recorded investments in loans	144,000		144,000		487,000
Recorded investment in troubled debt restructurings that subsequently defaulted within twelve months	340,000		340,000		144,000
Reserve for unfunded commitments	1,000,000		1,000,000		923,000
Provisions for (credits to) unfunded commitments	$ (92,000)	(77,000)	84,000	(27,000)
Charge-offs or recoveries related to reserve for unfunded commitments			$ 0		$ 0
Commercial Real Estate
Loans And Leases Receivable Disclosure [Line Items]
Number of loans modified under troubled debt restructuring | Loan	2		3
Loans modified as troubled debt restructurings	$ 545,000		$ 670,000
Commercial Loans
Loans And Leases Receivable Disclosure [Line Items]
Number of loans modified under troubled debt restructuring | Loan	5		5
Loans modified as troubled debt restructurings	$ 4,800,000		$ 4,800,000
Acquired Impaired Loans
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ (778,000)	$ 1,500,000	$ (1,100,000)	$ 1,600,000

Allowance for Loan and Lease 73

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	Jun. 30, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Recorded Investment	$ 33,573	$ 31,111
Unpaid Principal Balance	37,329	34,479
Related Allowance	4,895	3,965
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	10,735	11,425
Recorded Investment, With an allowance recorded	5,662	2,459
Unpaid Principal Balance, With no related allowance recorded	12,211	12,936
Unpaid Principal Balance, With an allowance recorded	5,975	2,634
Related Allowance	2,199	1,101
Residential Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	1,935	2,075
Recorded Investment, With an allowance recorded	338	354
Unpaid Principal Balance, With no related allowance recorded	1,910	2,046
Unpaid Principal Balance, With an allowance recorded	334	351
Related Allowance	127	158
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	4,391	5,470
Recorded Investment, With an allowance recorded	10,498	9,314
Unpaid Principal Balance, With no related allowance recorded	5,438	6,774
Unpaid Principal Balance, With an allowance recorded	11,447	9,724
Related Allowance	2,555	2,692
Installment and Other
Financing Receivable Impaired [Line Items]
Recorded Investment, With an allowance recorded	14	14
Unpaid Principal Balance, With an allowance recorded	14	14
Related Allowance	$ 14	$ 14

Allowance for Loan and Lease 74

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	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Financing Receivable Impaired [Line Items]
Average Recorded Investment	$ 32,987	$ 9,834
Interest Income Recognized	1,958	556
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	10,013	4,573
Average Recorded Investment, With an allowance recorded	4,587	667
Interest Income Recognized, With no related allowance recorded	436	199
Interest Income Recognized, With an allowance recorded	183
Residential Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	1,959	578
Average Recorded Investment, With an allowance recorded	347	240
Interest Income Recognized, With no related allowance recorded	25	24
Interest Income Recognized, With an allowance recorded	3	3
Construction, Land Development, and Other Land
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded		364
Average Recorded Investment, With an allowance recorded		87
Interest Income Recognized, With no related allowance recorded		15
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	7,283	1,119
Average Recorded Investment, With an allowance recorded	8,784	2,047
Interest Income Recognized, With no related allowance recorded	99	43
Interest Income Recognized, With an allowance recorded	233	263
Installment and Other
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With an allowance recorded	14	159
Interest Income Recognized, With an allowance recorded	$ 979	$ 9

Allowance for Loan and Lease 75

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	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 3,348,692	$ 2,277,492	$ 2,149,390
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,234,987	891,693	829,189
Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	699,588	577,218	584,716
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	188,616	105,429	92,635
Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,025,820	521,238	468,174
Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,806	4,228	3,515
Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	186,875	177,686	$ 171,161
Loans Excluding Acquired Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,035,606	1,949,802
Loans Excluding Acquired Impaired Loans | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,072,366	724,981
Loans Excluding Acquired Impaired Loans | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	569,851	432,656
Loans Excluding Acquired Impaired Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	183,756	99,483
Loans Excluding Acquired Impaired Loans | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,010,473	511,230
Loans Excluding Acquired Impaired Loans | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,285	3,766
Loans Excluding Acquired Impaired Loans | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	186,875	177,686
Loans Excluding Acquired Impaired Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,661,760	1,704,311
Loans Excluding Acquired Impaired Loans | Pass | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	938,889	638,066
Loans Excluding Acquired Impaired Loans | Pass | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	533,937	398,743
Loans Excluding Acquired Impaired Loans | Pass | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	151,868	73,935
Loans Excluding Acquired Impaired Loans | Pass | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	840,647	415,163
Loans Excluding Acquired Impaired Loans | Pass | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,253	3,732
Loans Excluding Acquired Impaired Loans | Pass | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	184,166	174,672
Loans Excluding Acquired Impaired Loans | Watch
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	274,739	176,996
Loans Excluding Acquired Impaired Loans | Watch | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	96,967	58,217
Loans Excluding Acquired Impaired Loans | Watch | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	30,482	29,165
Loans Excluding Acquired Impaired Loans | Watch | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	28,762	22,380
Loans Excluding Acquired Impaired Loans | Watch | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	118,385	67,024
Loans Excluding Acquired Impaired Loans | Watch | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3	20
Loans Excluding Acquired Impaired Loans | Watch | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	140	190
Loans Excluding Acquired Impaired Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	61,228	34,892
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	22,353	14,645
Loans Excluding Acquired Impaired Loans | Special Mention | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,815	2,251
Loans Excluding Acquired Impaired Loans | Special Mention | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,126	3,168
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	31,955	13,535
Loans Excluding Acquired Impaired Loans | Special Mention | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	15
Loans Excluding Acquired Impaired Loans | Special Mention | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	964	1,293
Loans Excluding Acquired Impaired Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	37,563	33,331
Loans Excluding Acquired Impaired Loans | Substandard | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,157	14,053
Loans Excluding Acquired Impaired Loans | Substandard | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,617	2,497
Loans Excluding Acquired Impaired Loans | Substandard | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	19,486	15,508
Loans Excluding Acquired Impaired Loans | Substandard | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14	14
Loans Excluding Acquired Impaired Loans | Substandard | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,289	1,259
Loans Excluding Acquired Impaired Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	316	272
Loans Excluding Acquired Impaired Loans | Doubtful | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 316	$ 272

Allowance for Loan and Lease 76

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Contractual Delinquency Information (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	$ 3,348,692	$ 2,277,492	$ 2,149,390
Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,234,987	891,693	829,189
Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	699,588	577,218	584,716
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	188,616	105,429	92,635
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,025,820	521,238	468,174
Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	12,806	4,228	3,515
Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	186,875	177,686	$ 171,161
Acquired Non-Impaired and Originated Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	34,045	30,950
Non-accrual	25,742	15,764
Current	3,001,561	1,918,852
Total loans and leases	3,035,606	1,949,802
Acquired Non-Impaired and Originated Loans | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,749	12,613
Acquired Non-Impaired and Originated Loans | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	5,357	2,573
Acquired Non-Impaired and Originated Loans | Greater than 90 Days and Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	197
Acquired Non-Impaired and Originated Loans | Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	12,714	14,210
Non-accrual	11,534	8,459
Current	1,059,652	710,771
Total loans and leases	1,072,366	724,981
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	544	4,783
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	636	968
Acquired Non-Impaired and Originated Loans | Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,126	2,240
Non-accrual	1,619	2,092
Current	567,725	430,416
Total loans and leases	569,851	432,656
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	492	148
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	15
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Current	183,756	99,483
Total loans and leases	183,756	99,483
Acquired Non-Impaired and Originated Loans | Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	16,862	11,982
Non-accrual	11,861	4,348
Current	993,611	499,248
Total loans and leases	1,010,473	511,230
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	560	6,667
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	4,244	967
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | Greater than 90 Days and Accruing
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	197
Acquired Non-Impaired and Originated Loans | Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	649	32
Non-accrual	14	14
Current	11,636	3,734
Total loans and leases	12,285	3,766
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	635	18
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,694	2,486
Non-accrual	714	851
Current	185,181	175,200
Total loans and leases	186,875	177,686
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	518	997
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	$ 462	$ 638

Servicing Assets - Activity for

Servicing Assets - Activity for Servicing Assets and Related Changes in Fair Value (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Transfers And Servicing [Abstract]
Beginning balance	$ 21,400	$ 21,091
Additions, net	4,191	2,948
Changes in fair value	(4,004)	(2,615)
Ending balance	$ 21,587	$ 21,424

Servicing Assets - Unpaid Princ

Servicing Assets - Unpaid Principal Balances of Loans Serviced for Others (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 1,195,570	$ 1,112,901
SBA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	1,111,551	1,021,143
USDA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 84,019	$ 91,758

Servicing Assets - Additional I

Servicing Assets - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Transfers And Servicing [Abstract]
Servicing fees, net of changes in fair value	$ 459,000	$ 1,076,000	$ 1,022,000	$ 1,995,000

Other Real Estate Owned - Chang

Other Real Estate Owned - Change in Other Real Estate Owned (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Banking And Thrift [Abstract]
Other real estate owned, beginning balance	$ 10,626	$ 16,570
Net additions to OREO	1,067	2,490
Dispositions of OREO	(5,231)	(6,056)
Valuation adjustments	(60)	(320)
Other real estate owned, ending balance	$ 6,402	$ 12,684

Other Real Estate Owned - Addit

Other Real Estate Owned - Additional Information (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 6,402,000	$ 10,626,000	$ 12,684,000	$ 16,570,000
Residential consumer mortgage loans in process of foreclosure	4,300,000	1,900,000
Residential Real Estate
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 843,000	$ 3,600,000

Goodwill, Core Deposit Intang82

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance, Goodwill			$ 54,562	$ 51,975
Additions			72,974
Ending balance, Goodwill	$ 127,536	$ 51,975	127,536	51,975
Amortization or accretion	(1,130)	(769)	(1,897)	(1,538)
Core Deposits
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance			16,720	19,776
Additions			19,060
Amortization or accretion			(1,863)	(1,529)
Ending balance	33,917	18,247	33,917	18,247
Accumulated amortization or accretion	15,329	$ 11,939	$ 15,329	$ 11,939
Weighted average remaining amortization or accretion period			7 years 1 month 6 days	6 years 1 month 6 days
Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Additions			$ 3,216
Amortization or accretion			(22)
Ending balance	3,194		3,194
Accumulated amortization or accretion	$ 22		$ 22
Weighted average remaining amortization or accretion period			11 years 10 months 24 days

Goodwill, Core Deposit Intang83

Goodwill, Core Deposit Intangible and Other Intangible Assets - Additional Information (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Indefinite Lived Intangible Assets By Major Class [Line Items]
Other intangible assets, net	$ 37,139,000	$ 16,756,000
Trademark
Indefinite Lived Intangible Assets By Major Class [Line Items]
Other intangible assets, net	$ 29,000	$ 36,000

Goodwill, Core Deposit Intang84

Goodwill, Core Deposit Intangible and Other Intangible Assets - Estimated Amortization Expense for Core Deposit Intangible, Customer Relationship Intangible and Other Intangible Assets Recognized (Details) $ in Thousands	Jun. 30, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2,018	$ 3,644
2,019	6,942
2,020	6,478
2,021	6,026
2,022	5,578
Thereafter	8,472
Total	$ 37,140

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended		12 Months Ended
	Mar. 31, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Income Tax Disclosure [Abstract]
Effective tax rate		20.00%	40.50%
Corporate federal income tax rate		21.00%		35.00%
Net income tax benefit	$ 724,000
Deferred tax assets, net		$ 48,900		$ 47,400

Deposits - Schedule of Deposits

Deposits - Schedule of Deposits (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Non-interest bearing demand deposits	$ 1,193,057	$ 760,887
Interest bearing checking accounts	287,330	186,611
Money market demand accounts	617,108	349,862
Other savings	487,130	437,212
Time deposits (below $250,000)	879,643	627,255
Time deposits ($250,000 and above)	180,609	81,502
Total deposits	$ 3,644,877	$ 2,443,329

Deposits - Additional Informati

Deposits - Additional Information (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Brokered deposits	$ 0	$ 0

Federal Home Loan Bank Advanc88

Federal Home Loan Bank Advances - Summary of FHLB Advances (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank advances	$ 420,000	$ 361,506
Weighted average cost	2.01%	1.49%

Federal Home Loan Bank Advanc89

Federal Home Loan Bank Advances - Additional Information (Details) - USD ($)	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank, total fixed-rate advances	$ 260,000,000
Federal home loan bank, total floating rate advances	$ 160,000,000
Federal home loan bank, required investment conversion ratio	0.05
Additional borrowing capacity from FHLB	$ 749,600,000	$ 795,000,000
Federal home loan bank advances maximum borrowing capacity as percentage of total assets	35.00%
2.03% Fixed-Rate Advances
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.03%
Federal home loan bank fixed rate advances, maturity date	2018-07
2.13% Fixed-Rate Advances
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.13%
Federal home loan bank fixed rate advances, maturity date	2018-09
Minimum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Floating interest rate	1.82%
Federal home loan bank floating rate advances, maturity date	2018-07
Maximum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Floating interest rate	1.84%
Federal home loan bank floating rate advances, maturity date	2018-08

Other Borrowings - Summary of O

Other Borrowings - Summary of Other Borrowings (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Securities sold under agreements to repurchase	$ 24,653	$ 31,187
Total	$ 24,653	$ 31,187

Other Borrowings - Additional I

Other Borrowings - Additional Information (Details) - USD ($)	Oct. 12, 2017	Jul. 31, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Apr. 30, 2017	Oct. 13, 2016
Line Of Credit Facility [Line Items]
Repayment of lines of credit		$ 16,200,000		$ 4,500,000
Short-term credit lines available for use, outstanding			$ 0		$ 0
Ridgestone | Correspondent Bank | Credit agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount							$ 30,000,000
Line of credit facility, maturity date			Oct. 12, 2017
Ridgestone | Correspondent Bank | Amended Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount			$ 0		$ 0
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, extended maturity date	Oct. 11, 2018
Line of credit facility, interest rate terms	The amended revolving line of credit bears interest at either the London Interbank Offered Rate (“LIBOR”) Rate plus 250 basis points or the Prime Rate minus 25 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 25 basis points. At June 30, 2018 and December 31, 2017, the line of credit has not been drawn upon, so an interest rate option has not been selected.
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%

Other Borrowings - Summary of S

Other Borrowings - Summary of Short-term Credit Lines Available for Use (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Federal Reserve Bank of Chicago Discount Window Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 329,627	$ 144,248
Available Federal Funds Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 55,000	$ 55,000

Junior Subordinated Debenture93

Junior Subordinated Debentures - Junior Subordinated Debentures by Issuance (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Mar. 31, 2018
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	$ 46,500	$ 36,500
Total liability, at carrying value	36,452	27,647
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	$ 1,500
First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	10,000
Junior Subordinated Debentures
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Discount	$ (10,048)	$ (8,853)
Junior Subordinated Debentures | Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 17, 2034
Contractual Rate	5.12%	4.39%
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%	5.09%	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	4.12%
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%

Junior Subordinated Debenture94

Junior Subordinated Debentures - Additional Information (Details) - USD ($)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017	Mar. 31, 2018
Debt Instrument [Line Items]
Principal amount	$ 46,500,000	$ 36,500,000
Accrued interest payable	2,562,000	1,306,000
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	5.12%	4.39%
Accrued interest payable	$ 67,000	$ 62,000
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	$ 1,500,000
RidgeStone Capital Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	6.38%	5.09%	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
First Evanston Bancorp Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	4.12%
Accrued interest payable	$ 17,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread	1.78%

Commitments and Contingent Li95

Commitments and Contingent Liabilities - Summary of Minimum Annual Rental Commitments for Operating Leases (Details) $ in Thousands	Jun. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 1,823
2,019	3,183
2,020	2,652
2,021	2,321
2,022	1,355
Thereafter	2,870
Total	$ 14,204

Commitments and Contingent Li96

Commitments and Contingent Liabilities - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Commitments And Contingencies Liabilities [Line Items]
Rental expenses		$ 1,600,000	$ 1,200,000	$ 2,800,000	$ 2,300,000
Sublease income		175,000	170,000	346,000	360,000
Minimum rental to be received in future on subleases	$ 1,600,000	1,600,000		$ 1,600,000
Sublease contract maturity year				2,025
Data processing		$ 10,371,000	$ 2,447,000	$ 12,672,000	$ 4,856,000
Fixed rate loan commitments maturity year				2,024
Variable rate loan commitments maturity year				2,040
Maximum
Commitments And Contingencies Liabilities [Line Items]
Commitments to make loans period				90 days
Loan commitments fixed interest rate	20.00%	20.00%		20.00%
Loan commitments variable interest rate	12.00%	12.00%		12.00%
Minimum
Commitments And Contingencies Liabilities [Line Items]
Loan commitments fixed interest rate	2.50%	2.50%		2.50%
Loan commitments variable interest rate	0.75%	0.75%		0.75%
Contract termination
Commitments And Contingencies Liabilities [Line Items]
Data processing	$ 8,100,000

Commitments and Contingent Li97

Commitments and Contingent Liabilities - Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	$ 80,436	$ 57,150
Variable Rate	973,755	470,766
Commitments to Extend Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	78,076	55,924
Variable Rate	947,386	467,429
Standby Letters of Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	2,360	1,226
Variable Rate	$ 26,369	$ 3,337

Fair Value Measurement - Summar

Fair Value Measurement - Summary of Financial Assets And Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017	Jun. 30, 2017	Dec. 31, 2016
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	$ 757,825	$ 583,236
Servicing assets, at fair value	21,587	21,400	$ 21,424	$ 21,091
Derivative assets	13,063	5,981
Derivative liabilities	2,869	994
U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	44,423	14,863
U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	145,009	52,958
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	59,293	33,170
Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	37,590	29,976
Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	6,656	5,284
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	21,587	21,400
Derivative assets	13,063	5,981
Derivative liabilities	2,869	994
Fair Value, Measurements, Recurring | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	44,423	14,863
Fair Value, Measurements, Recurring | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	145,009	52,958
Fair Value, Measurements, Recurring | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	59,293	33,170
Fair Value, Measurements, Recurring | Residential Mortgage-Backed Securities | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	299,534	307,457
Fair Value, Measurements, Recurring | Residential Mortgage-Backed Securities | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	61,963	39,514
Fair Value, Measurements, Recurring | Commercial Mortgage-Backed Securities | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	73,253	69,043
Fair Value, Measurements, Recurring | Commercial Mortgage-Backed Securities | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	30,104	30,971
Fair Value, Measurements, Recurring | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	37,590	29,976
Fair Value, Measurements, Recurring | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	6,656	5,284
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	44,423	14,863
Fair Value, Measurements, Recurring | Level 1 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	2,844	1,921
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	13,063	5,981
Derivative liabilities	2,867	994
Fair Value, Measurements, Recurring | Level 2 | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	145,009	52,958
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]
Available-for-sale Securities, Fair Value	58,604	32,795
Fair Value, Measurements, Recurring | Level 2 | Residential Mortgage-Backed Securities | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	299,534	307,457
Fair Value, Measurements, Recurring | Level 2 | Residential Mortgage-Backed Securities | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	61,963	39,514
Fair Value, Measurements, Recurring | Level 2 | Commercial Mortgage-Backed Securities | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	73,253	69,043
Fair Value, Measurements, Recurring | Level 2 | Commercial Mortgage-Backed Securities | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	30,104	30,971
Fair Value, Measurements, Recurring | Level 2 | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	37,590	29,976
Fair Value, Measurements, Recurring | Level 2 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	3,121	2,686
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	21,587	21,400
Derivative liabilities	2
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]
Available-for-sale Securities, Fair Value	689	375
Fair Value, Measurements, Recurring | Level 3 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	$ 691	$ 677

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Fair value, assets, level 1 to level 2 transfers, amount	$ 0	$ 0
Fair value, assets, level 2 to level 1 transfers, amount	0	0
Fair value, liabilities, level 1 to level 2 transfers, amount	0	0
Fair value, liabilities, level 2 to level 1 transfers, amount	0	0
Fair value, equity, level 1 to level 2 transfers, amount	0	0
Fair value, equity, level 2 to level 1 transfers, amount	$ 0	$ 0

Fair Value Measurement - Sum100

Fair Value Measurement - Summary of Financial Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Investment Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	$ 1,052	$ 1,080
Acquired assets at fair value	314
Amortization	3	2
Change in unrealized gain	11	(5)
Balance, end of period	1,380	1,077
Servicing Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	21,400	21,091
Additions, net	4,191	2,948
Change in fair value	(4,004)	(2,615)
Balance, end of period	$ 21,587	$ 21,424

Fair Value Measurement - Sum101

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	6 Months Ended
	Jun. 30, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate	6.60%
Expected weighted average loan life	2 months 12 days
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate	22.00%
Expected weighted average loan life	7 years 4 months 24 days
Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Discount rate	14.10%
Expected weighted average loan life	5 years 3 months 18 days
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Valuation Technique	Discounted cash flow
Impact to Valuation from an Increased or Higher Input Value	Decrease
Obligations of States, Municipalities, and Political Subdivisions | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Probability of default	1.30%
Obligations of States, Municipalities, and Political Subdivisions | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Probability of default	2.40%
Obligations of States, Municipalities, and Political Subdivisions | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Probability of default	1.80%
Single Issuer Trust Preferred
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Valuation Technique	Discounted cash flow
Impact to Valuation from an Increased or Higher Input Value	Decrease
Single Issuer Trust Preferred | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Probability of default	4.90%
Single Issuer Trust Preferred | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Probability of default	7.00%
Single Issuer Trust Preferred | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Probability of default	6.10%
Servicing Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Valuation Technique	Discounted cash flow
Impact to Valuation from an Increased or Higher Input Value	Decrease
Servicing Assets | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepayment speeds	4.60%
Servicing Assets | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepayment speeds	23.00%
Servicing Assets | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Prepayment speeds	10.00%

Fair Value Measurement - Sum102

Fair Value Measurement - Summary of Assets Measured at Fair Value on Non-recurring Basis, Excluding Acquired Impaired Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Commercial Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	$ 14,198	$ 12,783
Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	2,146	2,271
Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	12,334	12,092
Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	6,402	10,626
Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	11,428	9,779
Level 3 | Commercial Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	14,198	12,783
Level 3 | Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	2,146	2,271
Level 3 | Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	12,334	12,092
Level 3 | Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	6,402	10,626
Level 3 | Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	$ 11,428	$ 9,779

Fair Value Measurement - Sum103

Fair Value Measurement - Summary of Valuation Technique, Unobservable Inputs and Qualitative Information of Assets and Liabilities Measured at Fair Value on Non-recurring Basis (Details) - Level 3 - Fair Value Measurements, Non-recurring	6 Months Ended
	Jun. 30, 2018
Impaired Loans
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Valuation Technique	Appraisals
Impact to Valuation from an Increased or Higher Input Value	Decrease
Impaired Loans | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Appraisal adjustments, sales costs and other discount adjsutments for market conditions	6.00%
Impaired Loans | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Appraisal adjustments, sales costs and other discount adjsutments for market conditions	10.00%
Asset Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Valuation Technique	List price, contract price
Appraisal adjustments, sales costs and other discount adjsutments for market conditions	7.00%
Impact to Valuation from an Increased or Higher Input Value	Decrease
Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Valuation Technique	Appraisals
Impact to Valuation from an Increased or Higher Input Value	Decrease
Other Real Estate Owned | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Appraisal adjustments, sales costs and other discount adjsutments for market conditions	7.00%
Other Real Estate Owned | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Appraisal adjustments, sales costs and other discount adjsutments for market conditions	20.00%

Fair Value Measurement - Sum104

Fair Value Measurement - Summary of Estimated Fair Values of Financial Instruments and Levels Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Financial assets
Cash and due from banks	$ 25,299	$ 19,404
Interest bearing deposits with other banks	127,417	38,945
Securities held-to-maturity, fair value	104,411	117,277
Restricted stock, at cost	18,977	16,343
Loans held for sale	5,822	5,212
Loans and lease receivables, net	3,329,005	2,260,786
Accrued interest receivable	10,670	7,670
Financial liabilities
Federal Home Loan Bank advances	420,000	361,506
Securities sold under agreements to repurchase	24,653	31,187
Junior subordinated debentures issued to capital trusts, net	36,452	27,647
Level 1 | Carrying Amount
Financial assets
Cash and due from banks	25,299	19,404
Level 1 | Estimated Fair Value
Financial assets
Cash and due from banks	25,299	19,404
Level 2 | Carrying Amount
Financial assets
Interest bearing deposits with other banks	127,417	38,945
Securities held-to-maturity, fair value	106,613	117,163
Restricted stock, at cost	18,977	16,343
Financial liabilities
Non-interest bearing deposits	1,193,057	760,887
Interest bearing deposits	2,451,820	1,682,442
Accrued interest payable	2,562	1,306
Federal Home Loan Bank advances	420,000	361,506
Securities sold under agreements to repurchase	24,653	31,187
Level 2 | Estimated Fair Value
Financial assets
Interest bearing deposits with other banks	127,417	38,945
Securities held-to-maturity, fair value	104,411	117,277
Restricted stock, at cost	18,977	16,343
Financial liabilities
Non-interest bearing deposits	1,193,057	760,887
Interest bearing deposits	2,447,100	1,678,535
Accrued interest payable	2,562	1,306
Federal Home Loan Bank advances	420,000	361,500
Securities sold under agreements to repurchase	24,653	31,187
Level 3 | Carrying Amount
Financial assets
Loans held for sale	5,822	5,212
Loans and lease receivables, net	3,329,005	2,260,786
Accrued interest receivable	10,670	7,670
Financial liabilities
Junior subordinated debentures issued to capital trusts, net	36,452	27,647
Level 3 | Estimated Fair Value
Financial assets
Loans held for sale	6,494	5,851
Loans and lease receivables, net	3,288,358	2,240,235
Accrued interest receivable	10,670	7,670
Financial liabilities
Junior subordinated debentures issued to capital trusts, net	$ 42,475	$ 33,907

Derivative Instruments and H105

Derivative Instruments and Hedge Activities - Summary of Derivative Financial Instruments and Classification on Consolidated Statements of Financial Condition (Details) - USD ($)	Jun. 30, 2018	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Notional Amount	$ 465,265,000	$ 344,726,000
Other Assets	13,063,000	5,981,000
Other Liabilities	2,869,000	994,000
Cash Flow Hedges
Derivatives Fair Value [Line Items]
Notional Amount	250,000,000
Other Assets	10,238,000
Other Interest Rate Swaps
Derivatives Fair Value [Line Items]
Notional Amount	214,015,000
Other Assets	2,825,000
Other Liabilities	2,867,000
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	10,238,000	5,030,000
Other Liabilities		38,000
Derivatives Not Designated As Hedging Instruments | Other Credit Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	1,250,000
Other Liabilities	2,000
Derivatives Not Designated As Hedging Instruments | Other Interest Rate Swaps
Derivatives Fair Value [Line Items]
Notional Amount	214,015,000	94,726,000
Other Assets	2,825,000	951,000
Other Liabilities	$ 2,867,000	$ 956,000

Derivative Instruments and H106

Derivative Instruments and Hedge Activities - Additional Information (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative notional amount	$ 465,265,000		$ 465,265,000		$ 344,726,000
Unrealized gain (loss) to be reclassified as an decrease to interest expense during the next twelve months	2,300,000		2,300,000
Credit valuation adjustment increase (decrease) to non-interest income	(65,000)	$ (17,000)	(38,000)	$ (30,000)
Full collateral posted	12,100,000		12,100,000
Net credit exposure, excess collateral	0		0		378,000
Cash Flow Hedges
Derivative [Line Items]
Derivative notional amount	250,000,000		250,000,000
Interest Rate Swaps | Interest Expense
Derivative [Line Items]
Increase (decrease) in FHLB expense	(374,000)	213,000	(435,000)	267,000
Other Interest Rate Swaps
Derivative [Line Items]
Derivative notional amount	214,015,000		$ 214,015,000
Derivative maturity date, start year			Dec. 31, 2018
Derivative maturity date, end year			Apr. 30, 2028
Derivative instruments transaction fees	946,000	$ 65,000	$ 946,000	$ 179,000
Other Credit Derivative
Derivative [Line Items]
Derivative notional amount	1,300,000		1,300,000		0
Credit valuation adjustment increase (decrease) to non-interest income	1,000		24,000
Derivatives Designated as Hedging Instruments | Interest Rate Swaps | Cash Flow Hedges
Derivative [Line Items]
Derivative notional amount	250,000,000		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		$ 250,000,000

Derivative Instruments and H107

Derivative Instruments and Hedge Activities - Summary of Cash Flow Hedges (Details) - USD ($)	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 465,265,000	$ 344,726,000
Derivative assets fair value	13,063,000	5,981,000
Derivative liabilities fair value	2,869,000	$ 994,000
Cash Flow Hedges
Derivative [Line Items]
Notional Amount	250,000,000
Derivative assets fair value	$ 10,238,000
Weighted average pay rates	1.67%
Weighted average receive rates	1.63%
Weighted average maturity	4 years 2 months 12 days

Derivative Instruments and H108

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) - Interest Rate Swaps - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI (EffectivePortion)	$ 5,632	$ (1,425)
Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense	$ 435
Amount of Loss Reclassified from OCI to Income as an Increase to Interest Expense		$ (267)

Derivative Instruments and H109

Derivative Instruments and Hedge Activities - Summary of Other Interest Rate Swaps (Details) - USD ($)	6 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 465,265,000	$ 344,726,000
Derivative assets fair value	13,063,000	5,981,000
Derivative liabilities fair value	2,869,000	$ 994,000
Other Interest Rate Swaps
Derivative [Line Items]
Notional Amount	214,015,000
Derivative assets fair value	2,825,000
Derivative liabilities fair value	$ 2,867,000
Weighted average pay rates	4.66%
Weighted average receive rates	4.04%
Weighted average maturity	5 years 9 months 18 days

Derivative Instruments and H110

Derivative Instruments and Hedge Activities - Summary of Company's Interest Rate Derivative and Offsetting Positions (Details) - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Gross amounts recognized	$ 13,063	$ 5,981
Net amount presented in the Consolidated Statements of Financial Condition	13,063	5,981
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(1,091)	(232)
Collateral posted	(11,972)	(5,371)
Net credit exposure	0	378
Gross amounts recognized	2,869	994
Net amount presented in the Consolidated Statements of Financial Condition	2,869	994
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(1,091)	(232)
Collateral posted	(1,775)	(745)
Net credit exposure	$ 3	$ 17

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($)	Oct. 03, 2017	Jul. 06, 2017	Oct. 31, 2014	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
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				$ 1,135,000
Income tax benefit				125,000	$ 227,000
Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Income tax benefit				$ 91,000
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]
Issuance of common stock in connection with restricted stock awards, shares				126,157
Number of options exercised				94,750
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				1,355,545
Omnibus Plan | Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period						4 years
Shares of restricted voting common stock granted				126,157,000
Restricted shares vested				0
Fair value of unvested restricted stock awards				$ 4,300,000
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 | 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				126,157
Common stock, voting par value				$ 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				101,559
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				11,165
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
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				94,750		0
Number of shares outstanding				1,683,270		1,783,020
Award contractual term				7 years 1 month 6 days		7 years 7 months 6 days
Options vested				307,163
Proceeds from the exercise of stock options				$ 1,100,000
Income tax benefit				$ 275,000
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 granted				680,787
Number of shares outstanding				680,787
Award contractual term				5 years 3 months 18 days
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	6 Months Ended
	Jun. 30, 2018$ / sharesshares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, beginning balance	70,398,000
Number of shares, granted	126,157,000
Number of shares, vested	0
Number of shares, forfeited	(2,100,000)
Number of shares, ending balance	194,455,000
Weighted average grant date fair value, beginning balance | $ / shares	$ 20.31
Weighted average grant date fair value, granted | $ / shares	22.38
Weighted average grant date fair value, forfeited | $ / shares	20.84
Weighted average grant date fair value, ending balance | $ / shares	$ 21.65

Share-Based Compensation - S113

Share-Based Compensation - Summary of Stock Compensation Expense (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation - restricted stock	$ 450	$ 571
Income tax benefit	125	227
Unrecognized compensation expense	$ 271	$ 1,181
Weighted-average amortization period remaining	1 year 3 months 18 days	1 year 4 months 24 days
Restricted Shares
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation - restricted stock	$ 326
Income tax benefit	91
Unrecognized compensation expense	$ 3,691
Weighted-average amortization period remaining	3 years 3 months 18 days

Share-Based Compensation - Fair

Share-Based Compensation - Fair Value Assumptions of Stock Options (Details) - BYB Plan - $ / shares	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Time Options Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate, minimum	1.34%	1.68%
Risk-free interest rate, maximum	1.40%	1.85%
Expected stock price volatility	20.39%
Expected stock price volatility, minimum		16.18%
Expected stock price volatility, maximum		16.55%
Expected dividend yield	0.00%	0.00%
Weighted average grant date fair value	$ 3.55	$ 2.25
Time Options Grants | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	5 years 2 months 12 days	5 years 8 months 12 days
Time Options Grants | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Expected term (years)	5 years 7 months 6 days	6 years 3 months 18 days
Performance Options Grants
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Risk-free interest rate	Implied forward rates	Implied forward rates
Expected term (years)	Variable	Variable
Expected stock price volatility, minimum	20.34%	16.18%
Expected stock price volatility, maximum	20.39%	16.55%
Expected dividend yield	0.00%	0.00%
Weighted average grant date fair value	$ 3.75	$ 1.65

Share-Based Compensation - S115

Share-Based Compensation - Summary Activity in shares Subjected to Options and Weighted Average Exercise Prices (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 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	1,783,020
Number of Shares, Granted		0	212,400	1,634,568
Number of Shares, Exercised	(94,750)	0
Number of Shares, Forfeited	(5,000)
Number of Shares, Ending balance	1,683,270	1,783,020
Number of Shares, Exercisable	1,516,670
Weighted Average Exercise Price, Beginning balance	$ 11.91
Weighted Average Exercise Price, Exercised	11.98
Weighted Average Exercise Price, Forfeited	16.25
Weighted Average Exercise Price, Ending balance	11.89	$ 11.91
Weighted Average Exercise Price, Exercisable	$ 11.42
Intrinsic Value, Beginning balance	$ 19,718
Intrinsic Value, Exercised	988
Intrinsic Value, Ending balance	17,583	$ 19,718
Intrinsic Value, Exercisable	$ 16,568
Weighted Average Remaining Contractual Term (in Years)	7 years 1 month 6 days	7 years 7 months 6 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	7 years
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted	680,787
Number of Shares, Ending balance	680,787
Number of Shares, Exercisable	680,787
Weighted Average Exercise Price, Granted	$ 11.26
Weighted Average Exercise Price, Ending balance	11.26
Weighted Average Exercise Price, Exercisable	$ 11.26
Intrinsic Value, Granted	$ 7,544
Intrinsic Value, Ending balance	7,544
Intrinsic Value, Exercisable	$ 7,544
Weighted Average Remaining Contractual Term (in Years)	5 years 3 months 18 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	5 years 3 months 18 days

Earnings per Share - Additional

Earnings per Share - Additional Information (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share Basic [Line Items]
Shares outstanding	31,614,973	24,667,587	30,459,495	24,642,287
Stock Options
Earnings Per Share Basic [Line Items]
Shares outstanding			2,364,057	1,798,223
Restricted Stock Award
Earnings Per Share Basic [Line Items]
Shares outstanding			194,455	0

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 2,768	$ 6,146	$ 9,536	$ 12,706
Dividends on preferred shares	198	10,697	391	10,886
Net income available (loss attributable) to common stockholders	$ 2,570	$ (4,551)	$ 9,145	$ 1,820
Weighted-average common stock outstanding:
Weighted-average common stock outstanding (basic)	31,614,973	24,667,587	30,459,495	24,642,287
Incremental shares	953,423		988,825	464,600
Weighted-average common stock outstanding (dilutive)	32,568,396	24,667,587	31,448,320	25,106,887
Basic earnings per common share	$ 0.08	$ (0.18)	$ 0.30	$ 0.07
Diluted earnings per common share	$ 0.08	$ (0.18)	$ 0.29	$ 0.07

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Preferred and Common Stock (Details) - $ / shares	Jun. 30, 2018	Dec. 31, 2017
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	36,218,955	29,317,298
Common stock, voting shares outstanding	36,218,955	29,317,298
Series B 7.5% Fixed 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 - Summa119

Stockholders' Equity - Summary of Preferred and Common Stock (Parenthetical) (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2018	Dec. 31, 2017
Series B 7.5% Fixed 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		6 Months Ended		12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2016
Class Of Stock [Line Items]
Dividends declared and paid			$ 391,000	$ 385,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage					7.50%
Preferred stock, liquidation preference per share					$ 1,000
Dividends declared and paid	$ 198,000	$ 196,000	$ 391,000	$ 385,000

Consolidated Statements of C121

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		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			$ 458,578	$ 382,658
Reclassification of certain income tax effects from accumulated other comprehensive income			(763)
Other comprehensive income (loss), net of tax	$ (921)	$ 488	(4,485)	856
Ending balance	616,406	447,731	616,406	447,731
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			2,913	2,233
Reclassification of certain income tax effects from accumulated other comprehensive income			687
Other comprehensive income (loss), net of tax			3,750	(693)
Ending balance	7,350	1,540	7,350	1,540
Unrealized Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			(8,000)	(9,501)
Reclassification of certain income tax effects from accumulated other comprehensive income			(1,450)
Other comprehensive income (loss), net of tax			(8,235)	1,549
Ending balance	(17,685)	(7,952)	(17,685)	(7,952)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			(5,087)	(7,268)
Reclassification of certain income tax effects from accumulated other comprehensive income			(763)
Other comprehensive income (loss), net of tax			(4,485)	856
Ending balance	$ (10,335)	$ (6,412)	$ (10,335)	$ (6,412)