Byline Bancorp (BY) 10-Q 13 Nov 18 2018 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2018	Nov. 09, 2018
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	Q3
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 Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Common Stock, Shares Outstanding		36,311,686

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
ASSETS
Cash and due from banks	$ 25,162	$ 19,404
Interest bearing deposits with other banks	119,594	38,945
Cash and cash equivalents	144,756	58,349
Securities available-for-sale, at fair value	795,408	583,236
Securities held-to-maturity, at amortized cost (fair value September 30, 2018—$99,933, December 31, 2017—$117,277)	102,683	117,163
Restricted stock, at cost	19,202	16,343
Loans held for sale	8,737	5,212
Loans and leases:
Loans and leases	3,455,802	2,277,492
Allowance for loan and lease losses	(23,424)	(16,706)
Net loans and leases	3,432,378	2,260,786
Servicing assets, at fair value	20,674	21,400
Accrued interest receivable	11,331	7,670
Premises and equipment, net	106,948	95,224
Assets held for sale	8,343	9,779
Other real estate owned, net	4,891	10,626
Goodwill	127,536	54,562
Other intangible assets, net	35,248	16,756
Bank-owned life insurance	5,923	5,718
Deferred tax assets, net	42,287	47,376
Due from counterparty	14,484	39,824
Other assets	36,580	16,106
Total assets	4,917,409	3,366,130
LIABILITIES
Non-interest bearing demand deposits	1,175,222	760,887
Interest bearing deposits:
NOW, savings accounts, and money market accounts	1,455,295	973,685
Time deposits	1,110,250	708,757
Total deposits	3,740,767	2,443,329
Accrued interest payable	2,971	1,306
Federal Home Loan Bank advances	425,000	361,506
Securities sold under agreements to repurchase	24,446	31,187
Junior subordinated debentures issued to capital trusts, net	36,615	27,647
Accrued expenses and other liabilities	57,749	42,577
Total liabilities	4,287,548	2,907,552
STOCKHOLDERS’ EQUITY
Preferred stock	10,438	10,438
Common stock, voting, $0.01 par value at September 30, 2018 and December 31, 2017; 150,000,000 shares authorized at September 30, 2018 and December 31, 2017; 36,279,600 shares issued and outstanding at September 30, 2018 and 29,317,298 issued and outstanding at December 31, 2017	361	292
Additional paid-in capital	545,827	391,586
Retained earnings	85,597	61,349
Accumulated other comprehensive loss, net of tax	(12,362)	(5,087)
Total stockholders’ equity	629,861	458,578
Total liabilities and stockholders’ equity	$ 4,917,409	$ 3,366,130

CONSOLIDATED STATEMENTS OF FI_2

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Statement Of Financial Position [Abstract]
Securities held-to-maturity, fair value	$ 99,933	$ 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	36,279,600	29,317,298
Common stock, voting shares outstanding	36,279,600	29,317,298

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
INTEREST AND DIVIDEND INCOME
Interest and fees on loans and leases	$ 55,045,000	$ 30,933,000	$ 128,326,000	$ 88,510,000
Interest on taxable securities	5,076,000	3,720,000	13,703,000	11,213,000
Interest on tax-exempt securities	337,000	174,000	740,000	458,000
Other interest and dividend income	615,000	217,000	1,287,000	666,000
Total interest and dividend income	61,073,000	35,044,000	144,056,000	100,847,000
INTEREST EXPENSE
Deposits	5,971,000	2,112,000	12,214,000	5,518,000
Federal Home Loan Bank advances	1,723,000	850,000	4,441,000	2,282,000
Subordinated debentures and other borrowings	786,000	670,000	2,057,000	2,286,000
Total interest expense	8,480,000	3,632,000	18,712,000	10,086,000
Net interest income	52,593,000	31,412,000	125,344,000	90,761,000
PROVISION FOR LOAN AND LEASE LOSSES	5,842,000	3,900,000	14,913,000	9,306,000
Net interest income after provision for loan and lease losses	46,751,000	27,512,000	110,431,000	81,455,000
NON-INTEREST INCOME
ATM and interchange fees	1,781,000	1,495,000	4,140,000	4,342,000
Net gains on sales of securities available-for-sale			4,000	8,000
Net gains on sales of loans	5,015,000	7,499,000	22,214,000	24,026,000
Wealth management and trust income	674,000		866,000
Other non-interest income	1,672,000	547,000	4,058,000	2,104,000
Total non-interest income	11,143,000	11,918,000	37,073,000	37,419,000
NON-INTEREST EXPENSE
Salaries and employee benefits	21,312,000	16,323,000	58,834,000	50,151,000
Occupancy expense, net	3,548,000	3,301,000	11,802,000	10,525,000
Equipment expense	617,000	630,000	1,778,000	1,809,000
Loan and lease related expenses	1,015,000	891,000	3,886,000	2,569,000
Legal, audit and other professional fees	2,358,000	1,608,000	8,627,000	4,369,000
Data processing	2,724,000	2,399,000	15,396,000	7,255,000
Net loss (gain) recognized on other real estate owned and other related expenses	(284,000)	565,000	187,000	136,000
Regulatory assessments	675,000	326,000	1,282,000	894,000
Other intangible assets amortization expense	1,898,000	769,000	3,795,000	2,307,000
Advertising and promotions	537,000	196,000	1,133,000	803,000
Telecommunications	435,000	351,000	1,319,000	1,165,000
Other non-interest expense	3,121,000	3,706,000	7,606,000	7,182,000
Total non-interest expense	37,956,000	31,065,000	115,645,000	89,165,000
INCOME BEFORE PROVISION FOR INCOME TAXES	19,938,000	8,365,000	31,859,000	29,709,000
PROVISION (BENEFIT) FOR INCOME TAXES	5,402,000	(1,390,000)	7,787,000	7,248,000
NET INCOME	14,536,000	9,755,000	24,072,000	22,461,000
Dividends on preferred shares	196,000	195,000	587,000	11,081,000
INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 14,340,000	$ 9,560,000	$ 23,485,000	$ 11,380,000
EARNINGS PER COMMON SHARE
Basic	$ 0.40	$ 0.33	$ 0.73	$ 0.43
Diluted	$ 0.39	$ 0.32	$ 0.71	$ 0.43
Fees and Service Charges on Deposits [Member]
NON-INTEREST INCOME
Fees and charges	$ 1,825,000	$ 1,418,000	$ 4,593,000	$ 3,985,000
Net Servicing Fees [Member]
NON-INTEREST INCOME
Fees and charges	$ 176,000	$ 959,000	$ 1,198,000	$ 2,954,000

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 14,536	$ 9,755	$ 24,072	$ 22,461
Securities available-for-sale
Unrealized holding gains (losses) arising during the period	(3,451)	1,473	(14,859)	4,920
Reclassification adjustments for net gains included in net income			(4)	(8)
Tax effect	961	303	4,138	(1,587)
Net of tax	(2,490)	1,776	(10,725)	3,325
Cash flow hedges
Unrealized holding gains (losses) arising during the period	1,070	17	6,702	(1,408)
Reclassification adjustments for net (gains) losses included in net income	(428)	159	(863)	426
Tax effect	(179)	(88)	(1,626)	377
Net of tax	463	88	4,213	(605)
Total other comprehensive income (loss)	(2,027)	1,864	(6,512)	2,720
Comprehensive income	$ 12,509	$ 11,619	$ 17,560	$ 25,181

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	22,461				22,461
Other comprehensive income (loss), net of tax	2,720					2,720
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
Issuance of common stock in connection with restricted stock awards, shares			58,900
Forfeiture of restricted stock awards, shares			(400)
Cash dividends declared on preferred stock	(11,081)				(11,081)
Cash paid in lieu of fractional shares	(2)				(2)
Share-based compensation expense	951			951
Ending balance at Sep. 30, 2017	459,533	$ 10,438	$ 292	391,040	62,311	(4,548)
Ending balance, shares at Sep. 30, 2017		10,438	29,305,400
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	24,072				24,072
Other comprehensive income (loss), net of tax	(6,512)					(6,512)
Issuance of common stock upon exercise of stock options	1,702		$ 2	1,700
Issuance of common stock upon exercise of stock options, shares			146,513
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)
Issuance of common stock in connection with employee stock purchase plan	172			172
Issuance of common stock in connection with employee stock purchase plan, shares			8,882
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)	(763)				763	(763)
Cash dividends declared on preferred stock	(587)				(587)
Share-based compensation expense	1,161			1,161
Ending balance at Sep. 30, 2018	$ 629,861	$ 10,438	$ 361	$ 545,827	$ 85,597	$ (12,362)
Ending balance, shares at Sep. 30, 2018		10,438	36,279,600

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 24,072	$ 22,461
Adjustments to reconcile net income to net cash from operating activities:
PROVISION FOR LOAN AND LEASE LOSSES	14,913	9,306
Impairment loss on assets held for sale	256	951
Depreciation and amortization of premises and equipment	4,089	3,919
Net amortization of securities	2,553	3,544
Net gains on sales of securities available-for-sale	(4)	(8)
Losses on disposal of premises or equipment	194
Net gains on sales of assets held for sale	(1,102)	(167)
Net gains on sales of loans	(22,214)	(24,026)
Net proceeds from mortgage loans sold		151
Originations of government guaranteed loans	(237,945)	(202,176)
Proceeds from government guaranteed loans sold	279,390	228,852
Accretion of premiums and discounts on acquired loans, net	(14,239)	(24,767)
Net change in servicing assets	726	(578)
Net valuation adjustments on other real estate owned	512	735
Net gains on sales of other real estate owned	(380)	(1,538)
Other intangible assets amortization expense	3,795	2,307
Amortization of time deposit premium	(273)	(759)
Amortization of Federal Home Loan Bank advances premium	(19)	(156)
Accretion of junior subordinated debentures discount	471	556
Share-based compensation expense	1,161	951
Deferred tax provision	9,656	6,196
Increase in cash surrender value of bank owned life insurance	(205)	(209)
Net gain on death benefit of bank owned life insurance		(313)
Changes in assets and liabilities:
Accrued interest receivable	(593)	(324)
Other assets	(6,680)	515
Accrued interest payable	1,095	(1,243)
Accrued expenses and other liabilities	2,937	(11,382)
Net cash provided by operating activities	62,166	12,798
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of securities available-for-sale	(153,995)	(34,814)
Proceeds from maturities and calls of securities available-for-sale	13,630	7,672
Proceeds from paydowns of securities available-for-sale	45,785	53,171
Proceeds from sales of securities available-for-sale	544	8
Proceeds from maturities of securities held-to-maturity		655
Proceeds from paydowns of securities held-to-maturity	13,778	15,597
Purchases of Federal Home Loan Bank stock	(25,293)	(9,855)
Federal Home Loan Bank stock repurchases	23,794	14,220
Proceeds from other loans sold		9,984
Net change in loans and leases	(257,598)	(63,870)
Purchases of premises and equipment	(1,380)	(2,238)
Proceeds from sales of assets held for sale	4,414	4,398
Proceeds from sales of other real estate owned	6,686	9,583
Proceeds from bank owned life insurance death benefit		1,399
Net cash received in acquisition of business	20,374
Net cash (used in) provided by investing activities	(309,261)	5,910
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits	275,443	31,294
Proceeds from Federal Home Loan Bank advances	4,460,000	1,993,000
Repayments of Federal Home Loan Bank advances	(4,396,487)	(2,072,000)
Repayments of line of credit		(20,650)
Net (decrease) increase in securities sold under agreements to repurchase	(6,741)	13,558
Dividends paid on preferred stock	(587)	(11,081)
Cash paid in lieu of fractional shares		(2)
Proceeds from issuance of common stock upon exercise of stock options	1,702
Proceeds from issuance of common stock	172	76,829
Proceeds from issuance of preferred stock		1,050
Repurchase of preferred stock		(15,003)
Net cash provided by (used in) financing activities	333,502	(3,005)
NET INCREASE IN CASH AND CASH EQUIVALENTS	86,407	15,703
CASH AND CASH EQUIVALENTS, beginning of period	58,349	46,533
CASH AND CASH EQUIVALENTS, end of period	144,756	62,236
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest	16,868	11,689
Cash payments during the period for taxes	3,114	2,121
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in fair value of available-for-sale securities, net of tax	(10,725)	3,325
Change in fair value of cash flow hedges, net of tax	4,213	(605)
Delayed payments of mortgage-backed securities	229	389
Transfers of loans to loans held for sale		10,061
Transfers of loans to other real estate owned	1,527	6,069
Internally financed sale of other real estate owned	444
Transfers of land and premises to assets held for sale	2,531	3,372
Transfers of assets held for sale to premises and equipment	(415)
Transfers of premises and equipment to other assets	35	687
Transfers of other assets to assets held for sale	16
Due from counterparty	(5,503)	$ 21,084
Due to broker	6,983
Total assets acquired from acquisition	1,142,766
Total liabilities assumed from acquisition	1,036,609
Common stock and stock options issued due to business combination	$ 152,127

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 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 September 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. On October 17, 2018, we entered a definitive merger agreement with Oak Park River Forest Bankshares, Inc. (which we refer to as “Oak Park River Forest”), the parent company of Community Bank of Oak Park River Forest, to which the Company will acquire Oak Park River Forest through the merger of Oak Park River Forest with and into the Company, followed immediately by the merger of Community Bank of Oak Park River Forest with and into Byline Bank. At such time, Community Bank of Oak Park River Forest’s banking offices will become banking offices of the Bank. The above described merger agreements are anticipated to be completed during the first half of 2019, subject to the satisfaction or waiver of the conditions included in the merger agreement. No other subsequent events were identified that would have required a change to the consolidated financial statements or disclosure in the notes to the consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity. 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	9 Months Ended
	Sep. 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), and 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 (loss) 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. Fair Value Measurement (Topic 820) In August 2018, FASB issued ASU No. 2018-13, Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement . The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820. The amendments remove the disclosure requirements for the amount and reasons for transfers between Level 1 and Level 2 securities of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation processes for Level 3 fair value measurement. The amendments modify the disclosure requirements as follows: in lieu of a rollforward for Level 3 fair value measurements, a nonpublic entity is required to disclose transfers into and out of Level 3 of the fair value hierarchy and purchases and issues of Level 3 assets and liabilities; for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The amendments add the following disclosure requirements: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. This guidance is effective for annual and interim periods beginning after December 15, 2019. 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 early adopted these amendments in 2018, which did not have a material impact on the Company’s Consolidated Financial Statements.

Acquisition of a Business

Acquisition of a Business	9 Months Ended
	Sep. 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 $1.7 million and core system conversion expenses of $9.2 million related to the First Evanston acquisition, are reflected in non-interest expense on the Consolidated Statements of Operations for the nine months ended September 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 nine months ended September 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 Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Total revenues (net interest income and non-interest income) $ 63,736 $ 56,188 $ 183,564 $ 167,812 Net income $ 14,726 $ 12,553 $ 37,737 $ 31,626 Earnings per share—basic $ 0.40 $ 0.34 $ 1.03 $ 0.62 Earnings per share—diluted $ 0.39 $ 0.34 $ 1.01 $ 0.61 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 September 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	9 Months Ended
	Sep. 30, 2018
Investments Debt And Equity Securities [Abstract]
Securities	Note 4—Securities The following September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 55,717 $ — $ (384 ) $ 55,333 U.S. Government agencies 148,892 2 (2,274 ) 146,620 Obligations of states, municipalities, and political subdivisions 62,389 24 (1,186 ) 61,227 Residential mortgage-backed securities Agency 301,515 — (16,067 ) 285,448 Non-agency 75,763 — (2,200 ) 73,563 Commercial mortgage-backed securities Agency 75,380 154 (3,547 ) 71,987 Non-agency 31,535 — (1,489 ) 30,046 Small Business Administration mortgage-backed securities 26,715 9 — 26,724 Corporate securities 37,685 251 (523 ) 37,413 Other securities 4,611 2,591 (155 ) 7,047 Total $ 820,202 $ 3,031 $ (27,825 ) $ 795,408 September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,885 $ 14 $ (545 ) $ 23,354 Residential mortgage-backed securities Agency 42,668 40 (948 ) 41,760 Non-agency 36,130 — (1,311 ) 34,819 Total $ 102,683 $ 54 $ (2,804 ) $ 99,933 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 nine months ended September 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 September 30, 2018 and December 31, 2017 are summarized as follows: Less than 12 Months 12 Months or Longer Total September 30, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 23 $ 42,524 $ (196 ) $ 9,814 $ (188 ) $ 52,338 $ (384 ) U.S. Government agencies 52 92,091 (510 ) 52,536 (1,764 ) 144,627 (2,274 ) Obligations of states, municipalities and political subdivisions 133 40,567 (467 ) 14,693 (719 ) 55,260 (1,186 ) Residential mortgage-backed securities Agency 44 29,441 (886 ) 254,756 (15,181 ) 284,197 (16,067 ) Non-agency 9 69,533 (1,962 ) 4,029 (238 ) 73,562 (2,200 ) Commercial mortgage-backed securities Agency 8 7,181 (116 ) 53,213 (3,431 ) 60,394 (3,547 ) Non-agency 5 — — 30,046 (1,489 ) 30,046 (1,489 ) Corporate securities 12 19,286 (282 ) 4,691 (241 ) 23,977 (523 ) Other securities 1 — — 2,819 (155 ) 2,819 (155 ) Total 287 $ 300,623 $ (4,419 ) $ 426,597 $ (23,406 ) $ 727,220 $ (27,825 ) Less than 12 Months 12 Months or Longer Total September 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 29 $ 18,197 $ (444 ) $ 3,600 $ (101 ) $ 21,797 $ (545 ) Residential mortgage-backed securities Agency 18 24,101 (388 ) 14,465 (560 ) 38,566 (948 ) Non-agency 7 30,927 (1,105 ) 3,891 (206 ) 34,818 (1,311 ) Total 54 $ 73,225 $ (1,937 ) $ 21,956 $ (867 ) $ 95,181 $ (2,804 ) 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 nine months ended September 30, 2018 For the Three Months Ended For the Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Proceeds $ — $ — $ 544 $ 8 Gross gains — — 4 8 Gross losses — — — — There were no gains reclassified from income income Securities pledged at September 30, 2018 and December 31, 2017 had carrying amounts of $261.1 million and $262.5 million, At September 30, 2018, the Amortized Cost Fair Value Available-for-sale Due in one year or less $ 66,866 $ 66,842 Due from one to five years 179,535 176,765 Due from five to ten years 44,295 43,365 Due after ten years 14,525 14,312 Mortgage-backed securities 510,908 487,768 Other securities with no defined maturity 4,073 6,356 Total $ 820,202 $ 795,408 Held-to-maturity Due from one to five years $ 5,067 $ 4,966 Due from five to ten years 10,616 10,349 Due after ten years 8,202 8,039 Mortgage-backed securities 78,798 76,579 Total $ 102,683 $ 99,933

Loan and Lease Receivables

Loan and Lease Receivables	9 Months Ended
	Sep. 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: September 30, December 31, 2018 2017 Commercial real estate $ 1,272,208 $ 891,971 Residential real estate 705,132 577,123 Construction, land development, and other land 182,727 105,996 Commercial and industrial 1,095,946 522,254 Installment and other 12,150 4,182 Lease financing receivables 185,540 174,165 Total loans and leases 3,453,703 2,275,691 Net unamortized deferred fees and costs (1,418 ) (1,720 ) Initial direct costs 3,517 3,521 Allowance for loan and lease losses (23,424 ) (16,706 ) Net loans and leases $ 3,432,378 $ 2,260,786 September 30, December 31, 2018 2017 Lease financing receivables Net minimum lease payments $ 201,938 $ 188,986 Unguaranteed residual values 1,630 1,644 Unearned income (18,028 ) (16,465 ) Total lease financing receivables 185,540 174,165 Initial direct costs 3,517 3,521 Lease financial receivables before allowance for lease losses $ 189,057 $ 177,686 Total loans and leases consist of originated loans and leases, acquired impaired loans and acquired non-impaired loans and leases. At September 30, 2018 and December 31, 2017, total loans and leases included the guaranteed amount of U.S. Government guaranteed loans of $101.9 million and $77.0 million, respectively. At September 30, 2018 and December 31, 2017, installment and other loans included overdraft deposits of $1.1 million and $617,000, respectively, which were reclassified as loans. At September 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 $ 17,443 2019 69,639 2020 53,597 2021 34,663 2022 19,821 Thereafter 6,775 Total $ 201,938 Originated Topic Topic September 30, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 619,767 $ 154,108 $ 498,329 $ 1,272,204 Residential real estate 445,717 120,963 138,516 705,196 Construction, land development, and other land 140,391 4,203 37,111 181,705 Commercial and industrial 696,750 14,436 384,260 1,095,446 Installment and other 7,729 458 4,007 12,194 Lease financing receivables 155,825 — 33,232 189,057 Total loans and leases $ 2,066,179 $ 294,168 $ 1,095,455 $ 3,455,802 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 September 30, 2018 December 31, 2017 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 169,149 $ 154,108 $ 235,898 $ 166,712 Residential real estate 123,542 120,963 207,660 144,562 Construction, land development, and other land 4,615 4,203 13,270 5,946 Commercial and industrial 23,467 14,436 18,333 10,008 Installment and other 1,126 458 1,819 462 Total acquired impaired loans $ 321,899 $ 294,168 $ 476,980 $ 327,690 The following table summarizes the changes in accretable yield for acquired impaired loans for the three and nine months ended September 30, 2018 and 2017: Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Beginning balance $ 41,306 $ 37,619 $ 36,446 $ 36,868 Additions — — 3,566 — Accretion to interest income (5,665 ) (8,165 ) (17,227 ) (24,768 ) Reclassification from nonaccretable difference, net 2,507 6,901 15,363 24,255 Ending balance $ 38,148 $ 36,355 $ 38,148 $ 36,355 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 September 30, 2018 December 31, 2017 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 506,507 $ 498,329 $ 221,710 $ 211,359 Residential real estate 141,011 138,516 32,605 32,085 Construction, land development, and other land 39,694 37,111 1,926 1,845 Commercial and industrial 397,746 384,260 105,529 94,731 Installment and other 7,601 4,007 355 42 Lease financing receivables 34,706 33,232 37,476 36,357 Total acquired non-impaired loans and leases $ 1,127,265 $ 1,095,455 $ 399,601 $ 376,419

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	Note 6—Allowance for Loans and leases The following September 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 $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 Provisions 1,705 29 58 3,579 12 459 5,842 Charge-offs (736 ) — — (858 ) (4 ) (823 ) (2,421 ) Recoveries — — — 75 — 241 316 Ending balance $ 7,422 $ 1,677 $ 390 $ 11,165 $ 38 $ 2,732 $ 23,424 Nine months ended Beginning balance $ 4,794 $ 1,638 $ 222 $ 7,418 $ 41 $ 2,593 $ 16,706 Provisions 3,975 39 586 8,959 33 1,321 14,913 Charge-offs (1,347 ) — (418 ) (5,539 ) (36 ) (1,888 ) (9,228 ) Recoveries — — — 327 — 706 1,033 Ending balance $ 7,422 $ 1,677 $ 390 $ 11,165 $ 38 $ 2,732 $ 23,424 Ending balance: Individually evaluated for impairment $ 2,294 $ 70 $ — $ 4,044 $ 14 $ — $ 6,422 Collectively evaluated for impairment 3,413 1,150 390 6,301 21 2,732 14,007 Loans acquired with deteriorated credit quality 1,715 457 — 820 3 — 2,995 Total allowance for loan and lease losses $ 7,422 $ 1,677 $ 390 $ 11,165 $ 38 $ 2,732 $ 23,424 September 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 $ 13,612 $ 1,941 $ — $ 19,962 $ 14 $ — $ 35,529 Collectively evaluated for impairment 1,104,484 582,292 177,502 1,061,048 11,722 189,057 3,126,105 Loans acquired with deteriorated credit quality 154,108 120,963 4,203 14,436 458 — 294,168 Total loans and leases $ 1,272,204 $ 705,196 $ 181,705 $ 1,095,446 $ 12,194 $ 189,057 $ 3,455,802 September 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 $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 Provisions (releases) 1,577 52 (111 ) 1,440 13 929 3,900 Charge-offs (186 ) (161 ) — (763 ) (327 ) (862 ) (2,299 ) Recoveries — — — — — 410 410 Ending balance $ 5,059 $ 1,726 $ 216 $ 6,366 $ 30 $ 2,583 $ 15,980 Nine months ended Beginning balance $ 1,945 $ 2,483 $ 742 $ 4,196 $ 334 $ 1,223 $ 10,923 Provisions (releases) 3,591 (400 ) (526 ) 3,932 23 2,686 9,306 Charge-offs (477 ) (357 ) — (1,762 ) (327 ) (2,399 ) (5,322 ) Recoveries — — — — — 1,073 1,073 Ending balance $ 5,059 $ 1,726 $ 216 $ 6,366 $ 30 $ 2,583 $ 15,980 Ending balance: Individually evaluated for impairment $ 1,186 $ 176 $ — $ 1,585 $ 2 $ — $ 2,949 Collectively evaluated for impairment 1,844 1,237 155 3,389 10 2,583 9,218 Loans acquired with deteriorated credit quality 2,029 313 61 1,392 18 — 3,813 Total allowance for loan and lease losses $ 5,059 $ 1,726 $ 216 $ 6,366 $ 30 $ 2,583 $ 15,980 September 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 $ 14,928 $ 1,948 $ 565 $ 6,075 $ 2 $ — $ 23,518 Collectively evaluated for impairment 673,851 428,565 88,315 484,547 2,762 172,341 1,850,381 Loans acquired with deteriorated credit quality 173,106 152,149 5,424 11,433 488 — 342,600 Total loans and leases $ 861,885 $ 582,662 $ 94,304 $ 502,055 $ 3,252 $ 172,341 $ 2,216,499 The Company increased the allowance for loan and lease losses by $3.7 million and $6.7 million for the three and nine months ended September 30, 2018, respectively. The Company increased the allowance for loan and lease losses by $2.0 million and $5.1 million for three and nine months ended September 30, 2017, respectively. For acquired impaired loans, the Company increased the allowance for loan and lease losses by $244,000 for the three months ended September 30, 2018, and decreased the allowance for loan and lease losses by $879,000 for the nine months ended September 30, 2018. The Company increased the allowance for loan and lease losses for acquired impaired loans by $559,000 and $2.2 million for the three and nine months ended September 30, 2017, respectively. The following and September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 8,439 $ 9,566 $ — Residential real estate 1,689 1,655 — Commercial and industrial 9,971 11,694 — With an allowance recorded Commercial real estate 5,173 5,419 2,294 Residential real estate 252 253 70 Commercial and industrial 9,991 10,535 4,044 Installment and other 14 14 14 Total impaired loans $ 35,529 $ 39,136 $ 6,422 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 nine months ended as follows: September 30, 2018 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 9,441 $ 232 Residential real estate 1,910 24 Construction, land development and other land — 15 Commercial and industrial 8,018 194 With an allowance recorded Commercial real estate 5,022 16 Residential real estate 330 3 Commercial and industrial 9,047 484 Installment and other 14 9 Total impaired loans $ 33,782 $ 977 September 30, 2017 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 10,605 $ 419 Residential real estate 1,698 33 Construction, land development and other land 269 2 Commercial and industrial 2,391 253 With an allowance recorded Commercial real estate 1,043 287 Residential real estate 444 4 Construction, land development and other land 19 — Commercial and industrial 1,673 500 Installment and other 213 11 Total impaired loans $ 18,355 $ 1,509 For purposes The following September 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 $ 1,017,225 $ 544,986 $ 159,712 $ 915,027 $ 11,696 $ 187,623 $ 2,836,269 Watch 71,382 30,287 14,691 128,597 — 100 245,057 Special Mention 14,508 5,729 3,099 15,654 13 856 39,859 Substandard 14,981 3,231 — 21,732 27 317 40,288 Doubtful — — — — — 161 161 Loss — — — — — — — Total $ 1,118,096 $ 584,233 $ 177,502 $ 1,081,010 $ 11,736 $ 189,057 $ 3,161,634 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 September 30, 2018 and December 31, 2017: September 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 $ 5,452 $ 1,282 $ — $ 12,553 $ 19,287 $ 1,098,809 $ 1,118,096 Residential real estate 434 196 — 1,631 2,261 581,972 584,233 Construction, land development, and other land — — — — — 177,502 177,502 Commercial and industrial 3,600 2,361 291 13,958 20,210 1,060,800 1,081,010 Installment and other 34 1 — 23 58 11,678 11,736 Lease financing receivables 1,511 624 — 478 2,613 186,444 189,057 Total $ 11,031 $ 4,464 $ 291 $ 28,643 $ 44,429 $ 3,117,205 $ 3,161,634 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 Trouble debt restructurings are granted due to borrower financial difficulty and provide for a modification of loan repayment terms. TDRs are treated in the same manner as impaired loans for purposes of calculating the allowance for loan and lease losses. The tables below present TDRs by loan category as September 30, 2018 and December 31, 2017: September 30, 2018 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 3 $ 914 $ 914 $ — $ 113 Commercial and industrial 2 193 193 — 107 Residential real estate 1 123 123 — — Total accruing 6 1,230 1,230 — 220 Non-accruing: Commercial real estate 8 2,678 2,637 41 420 Commercial and industrial 4 6,593 4,722 1,871 1,155 Total non-accruing 12 9,271 7,359 1,912 1,575 Total troubled debt restructurings 18 10,501 8,589 1,912 1,795 December 31, 2017 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 3 $ 912 $ 912 $ — $ — Residential real estate 1 149 149 — — Total accruing 4 1,061 1,061 — — Non-accruing: Commercial real estate 2 743 743 — 111 Commercial and industrial 3 1,246 759 487 246 Residential real estate 1 67 67 — — Total non-accruing 6 2,056 1,569 487 357 Total troubled debt restructurings 10 3,117 2,630 487 357 In addition, Loans modified three and nine months ended September 30, 2018 For the Three Months Ended For the Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Accruing: Beginning balance $ 1,238 $ 981 $ 1,061 $ 602 Additions — 673 37 1,017 Net payments (8 ) (23 ) (56 ) (59 ) Net transfers from non-accrual — — 188 71 Ending balance 1,230 1,631 1,230 1,631 Non-accruing: Beginning balance 5,776 470 1,570 552 Additions 1,667 194 7,123 194 Net payments (84 ) (8 ) (1,002 ) (19 ) Charge-offs — — (144 ) — Net transfers to accrual — — (188 ) (71 ) Ending balance 7,359 656 7,359 656 Total troubled debt restructurings 8,589 2,287 8,589 2,287 Troubled No troubled At September 30, 2018 and December 31, 2017, the During the three months ended September 30, 2018 and 2017, the nine months ended September 30, 2018 and 2017

Servicing Assets

Servicing Assets	9 Months Ended
	Sep. 30, 2018
Transfers And Servicing [Abstract]
Servicing Assets	Note 7—Servicing Activity for the three and nine months ended September 30, 2018 is Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 21,587 $ 21,424 $ 21,400 $ 21,091 Additions, net 1,489 1,727 5,680 4,675 Changes in fair value (2,402 ) (1,482 ) (6,406 ) (4,097 ) Ending balance $ 20,674 $ 21,669 $ 20,674 $ 21,669 Loans serviced as of September 30, 2018 and December 31, 2017 were as follows: September 30, December 31, 2018 2017 Loan portfolios serviced for: SBA guaranteed loans $ 1,135,871 $ 1,021,143 USDA guaranteed loans 86,417 91,758 Total $ 1,222,288 $ 1,112,901 During the three months ended September 30, 2018 and 2017, loan servicing income, net of changes in fair value of servicing assets were $176,000 and $1.0 million, respectively. During the nine months ended September 30, 2018 and 2017, loan servicing income, net of changes in fair value of servicing assets were $1.2 million and $3.0 million, respectively. The fair Generally, as interest rates rise on variable rate loans, loan prepayments increase due to an increase in refinance activity, which may result in a decrease in the fair value of servicing assets. Measurement of fair value is limited to the 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	9 Months Ended
	Sep. 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 three and nine months ended September 30, 2018 and 2017. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 6,402 $ 12,684 $ 10,626 $ 16,570 Net additions to OREO 307 3,417 1,527 6,069 Dispositions of OREO (1,519 ) (1,989 ) (6,750 ) (8,045 ) Valuation adjustments (299 ) (253 ) (512 ) (735 ) Ending balance $ 4,891 $ 13,859 $ 4,891 $ 13,859 At September 30, 2018 and December 31, 2017, the balance of real estate owned included $657,000 and $3.6 million, respectively, of foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property. At September 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 $3.1 million and $1.9 million, respectively.

Goodwill, Core Deposit Intangib

Goodwill, Core Deposit Intangible and Other Intangible Assets	9 Months Ended
	Sep. 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 tables summarize the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the three and nine months ended September 30, 2018 and 2017: Nine Months Ended September 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 — (3,685 ) (89 ) — (2,293 ) — Ending balance $ 127,536 $ 32,095 $ 3,127 $ 51,975 $ 17,483 $ — Accumulated amortization N/A $ 17,151 $ 89 N/A $ 12,703 N/A Weighted average remaining amortization period N/A 7.1 Years 11.7 Years N/A 5.8 Years N/A Three Months Ended September 30, 2018 2017 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 127,536 $ 33,917 $ 3,194 $ 51,975 $ 18,247 $ — Additions — — — — — — Amortization — (1,822 ) (67 ) — (764 ) — Ending balance $ 127,536 $ 32,095 $ 3,127 $ 51,975 $ 17,483 $ — Accumulated amortization N/A $ 17,151 $ 89 N/A $ 12,703 N/A Weighted average remaining amortization period N/A 7.1 Years 11.7 Years N/A 5.8 Years N/A The Company added additional goodwill, core deposit intangible assets, and customer relationship intangible assets in conjunction with the First Evanston acquisition. Please refer to Note 3—Acquisition of a Business for further details. Additionally, the Company had other intangible assets of $26,000 and $36,000 as of September 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 September 30, 2018: Estimated Amortization 2018 $ 1,807 2019 6,945 2020 6,477 2021 6,026 2022 5,578 Thereafter 8,415 Total $ 35,248

Income Taxes

Income Taxes	9 Months Ended
	Sep. 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 rate for the nine months ended September 30, 2018 and 2017 was 24.4%. The current effective tax rate reflects the passage of the Tax Cuts and Jobs Act (the “Tax Act”), which was enacted on December 22, 2017. Among other things, the Tax Act reduces the corporate federal income tax rate from 35% to 21%, effective January 1, 2018. Also on December 22, 2017, the SEC issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for the Tax Act’s impact. SAB 118 provides a measurement period, not to extend beyond one year from the date of enactment during which a company, acting in good faith, may complete the accounting for the impacts of the Tax Act. The Company recorded an additional discrete income tax benefit of $724,000 during the first quarter of 2018. This adjustment includes the impact of the federal income tax rate decrease due to the 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. As part of a budget package passed by the Legislature of the State of Illinois, the corporate income tax rate increased from 5.25% to 7.00% effective July 1, 2017. As a result of the increase in the corporate income tax rate, during the third quarter of 2017 we recorded a state income tax benefit of $4.6 million due to increased value of our deferred tax asset related to our Illinois net loss deduction. Net deferred tax assets decreased to $42.3 million at September 30, 2018 compared to $47.4 million at December 31, 2017. The net decrease in the total net deferred tax assets recorded as of September 30, 2018 was a result of a reduction due to the utilization of net operating loss carryforward deferred tax assets, partially offset with an increase in net deferred tax assets related to the acquisition of First Evanston.

Deposits

Deposits	9 Months Ended
	Sep. 30, 2018
Deposits [Abstract]
Deposits	Note 11—Deposits The composition of deposits was as follows as of September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 Non-interest bearing demand deposits $ 1,175,222 $ 760,887 Interest bearing checking accounts 317,145 186,611 Money market demand accounts 661,271 349,862 Other savings 476,879 437,212 Time deposits (below $250,000) 916,014 627,255 Time deposits ($250,000 and above) 194,236 81,502 Total deposits $ 3,740,767 $ 2,443,329 Time deposits of $250,000 or more included $10.0 million of brokered deposits at September 30, 2018 and

Federal Home Loan Bank Advances

Federal Home Loan Bank Advances	9 Months Ended
	Sep. 30, 2018
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank Advances	Note 12—Federal The following September 30, December 31, 2018 2017 Federal Home Loan Bank advances $ 425,000 $ 361,506 Weighted average cost 2.30 % 1.49 % At September 30, 2018, fixed-rate advances totaled $250.0 million with an interest rate of 2.36% September 30, 2018, and October The Company’s required investment in FHLB stock is $4.50 for every $100 in advances. At September 30, 2018 and December 31, 2017, the Bank has additional borrowing capacity from the FHLB of $1.2 billion 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	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Other Borrowings	Note 13—Other Borrowings The following is a summary of the Company’s other borrowings as of September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 Securities sold under agreements to repurchase $ 24,446 $ 31,187 Line of credit — — Total $ 24,446 $ 31,187 Securities On September 30, 2018 The following September 30, December 31, 2018 2017 Federal Reserve Bank of Chicago discount window line $ 310,345 $ 144,248 Available federal funds lines 55,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Junior Subordinated Debentures	Note 14—Junior Subordinated Debentures At September 30, 2018 and December 31, 2017, the Name of Trust Aggregate Principal Amount September 30, 2018 Aggregate Principal Amount December 31, 2017 Stated Maturity Contractual Rate at September 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 4.11 % Three-month LIBOR + 1.78% Total liability, at par 46,500 36,500 Discount (9,885 ) (8,853 ) Total liability, at carrying value $ 36,615 $ 27,647 In 2004, the September 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 September 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. Accrued interest payable was $25,000 as of September 30, 2018. There was no accrued interest payable as of 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% (4.11% at September 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	9 Months Ended
	Sep. 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 $ 944 2019 3,316 2020 2,777 2021 2,450 2022 1,488 Thereafter 3,167 Total $ 14,142 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 September 30, 2018 and December 31, 2017 September 30, December 31, 2018 2017 Fixed Rate Variable Rate Fixed Rate Variable Rate Commitments to extend credit $ 74,062 $ 944,577 $ 55,924 $ 467,429 Letters of credit 1,985 24,105 1,226 3,337 Total $ 76,047 $ 968,682 $ 57,150 $ 470,766 Commitments Letters Commitments

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 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 September 30, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 55,333 $ 55,333 $ — $ — U.S. Government agencies 146,620 — 146,620 — Obligations of states, municipalities, and political subdivisions 61,227 — 60,538 689 Residential mortgage-backed securities Agency 285,448 — 285,448 — Non-agency 73,563 — 73,563 — Commercial mortgage-backed securities Agency 71,987 — 71,987 — Non-agency 30,046 — 30,046 — Small Business Administration mortgage-backed securities 26,724 — 26,724 — Corporate securities 37,413 — 37,413 — Other securities 7,047 2,819 3,536 692 Servicing assets 20,674 — — 20,674 Derivative assets 13,620 — 13,620 — Financial liabilities Derivative liabilities 2,769 — 2,769 — 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 nine months ended September 30, 2018 or 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): Nine Months Ended September 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 — — 5,680 4,675 Amortization 4 3 — — Change in unrealized gain 11 6 — — Changes in fair value — — (6,406 ) (4,097 ) Balance, end of period $ 1,381 $ 1,089 $ 20,674 $ 21,669 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 2.1%—25.9% 10.9 % Decrease Discount rate 7.7%—24.4% 14.9 % Decrease Expected weighted average loan life 0.8—10.8 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 September 30, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 11,318 $ — $ — $ 11,318 Residential real estate 1,871 — — 1,871 Construction, land development, and other land — — — — Commercial and industrial 15,918 — — 15,918 Installment and other — — — — Assets held for sale 8,343 — — 8,343 Other real estate owned 4,891 — — 4,891 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 Cash and cash equivalent s —For these short-term instruments, the carrying amount is a reasonable estimate of fair value. Securities y —The Company obtains fair value measurements from an independent pricing service. Management reviews the procedures used by the third party, including significant inputs used in the fair value calculations. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. When market quotes are not readily accessible or available, alternative approaches are utilized, such as matrix or model pricing. Restricted k —The fair value has been determined to approximate cost. Loans held for — The fair value of loans held for sale are based on quoted market prices, where available, and determined by discounted estimated cash flows using interest rates approximating the Company’s current origination rates for similar loans adjusted to reflect the inherent credit risk. Loan —For certain variable rate loans that reprice frequently and with no significant changes in credit risk, fair value is estimated at carrying value. The fair value of other types of loans is estimated by discounting future cash flows, using current rates at which similar loans would be made to borrowers with similar credit ratings and for the same remaining maturities. Deposits —The fair value of demand deposits, savings accounts, and certain money market deposits is the amount payable on demand at the reporting date. The fair value of fixed-maturity certificates of deposit is estimated by discounting future cash flows, using rates currently offered for deposits of similar remaining maturities. Federal —The fair value of FHLB advances is estimated by discounting the agreements based on maturities using rates currently offered for FHLB advances of similar remaining maturities adjusted for prepayment penalties that would be incurred if the borrowings were paid off on the measurement date. Securities e —The carrying amount approximates fair value due to maturities of less than ninety days. Junior subordinated debenture s —The fair value of junior subordinated debentures, in the form of trust preferred securities, is determined using rates currently available to the Company for debt with similar terms and remaining maturities. Accrued interest —The carrying amount approximates fair value. Commitments t —The fair values of these off-balance sheet commitments to extend credit and commercial and letters of credit are not considered practicable to estimate because of the lack of quoted market prices and the inability to estimate fair value without incurring excessive costs. The estimated September 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 $ 25,162 $ 25,162 $ 19,404 $ 19,404 Interest bearing deposits with other banks 2 119,594 119,594 38,945 38,945 Securities held-to-maturity 2 102,683 99,933 117,163 117,277 Other restricted stock 2 19,202 19,202 16,343 16,343 Loans held for sale 3 8,737 9,707 5,212 5,851 Loans and lease receivables, net 3 3,432,378 3,356,116 2,260,786 2,240,235 Accrued interest receivable 3 11,331 11,331 7,670 7,670 Financial liabilities Non-interest bearing deposits 2 1,175,222 1,175,222 760,887 760,887 Interest bearing deposits 2 2,565,545 2,561,465 1,682,442 1,678,535 Accrued interest payable 2 2,971 2,971 1,306 1,306 Line of credit 2 — — — — Federal Home Loan Bank advances 2 425,000 425,000 361,506 361,500 Securities sold under repurchase agreement 2 24,446 24,446 31,187 31,187 Junior subordinated debentures 3 36,615 42,693 27,647 33,907

Derivative Instruments and Hedg

Derivative Instruments and Hedge Activities	9 Months Ended
	Sep. 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 September 30, 2018 and December 31, 2017: September 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 $ 10,883 $ — $ 250,000 $ 5,030 $ 38 Derivatives not designated as hedging instruments Other interest rate swaps 236,916 2,737 2,766 94,726 951 956 Other credit derivatives 4,504 — 3 — — — Total derivatives $ 491,420 $ 13,620 $ 2,769 $ 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 September 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 nine months ended September 30, 2018 and 2017. Interest recorded on these swap transactions reduced FHLB interest expense by $428,000 The following table reflects the cash flow hedges as of September 30, 2018: Notional amounts $ 250,000 Derivative assets fair value 10,883 Derivative liabilities fair value — Weighted average pay rates 1.67 % Weighted average receive rates 2.33 % Weighted average maturity 3.4 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 nine months ended: September 30, 2018 September 30, 2017 Amount of Gain (Loss) Recognized in OCI (Effective Portion) Amount of Gain (Loss) 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 Gain (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 $ 6,702 $ 863 $ — $ (1,408 ) $ (426 ) $ — Other interest rate swaps —The total combined notional amount was $236.9 million as of September 30, 2018 with maturities ranging from December 2018 to August 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 nine months ended September 30, 2018, there were $230,000 and $1.2 million of transaction fees, respectively, included in other non-interest income, related to these derivative instruments. During the three and nine months ended September 30, 2017, transaction fees were $40,000 and $219,000, respectively. The following table reflects other interest rate swaps as of September 30, 2018: Notional amounts $ 236,916 Derivative assets fair value 2,737 Derivative liabilities fair value 2,766 Weighted average pay rates 4.64 % Weighted average receive rates 4.19 % Weighted average maturity 5.7 years Other credit derivatives— The total notional amount was $4.5 million as of September 30, 2018. There were no credit derivatives as of or for the year ended December 31, 2017. The fair value of the other credit derivatives are reflected in other liabilities with corresponding gains or losses reflected in non-interest income. The credit valuation adjustment (“CVA”) related to the other credit derivatives resulted in an increase to other non-interest income during the three and nine months ended September 30, 2018 of $34,000 and $57,000, 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 months ended September 30, 2018, the CVA resulted in an increase to non-interest income of $13,000. During the nine months ended September 30, 2018, the CVA resulted in a decrease to non-interest income of $25,000, respectively. During the three and nine months ended September 30, 2017, the CVA resulted in a decrease to non-interest income of $6,000 and $36,000, respectively. The Company has entered into risk participation agreements with counterparty banks to assume a portion of the credit risk related to borrower transactions. The credit risk related to these other credit derivatives is managed through the Company’s loan underwriting process. 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: September 30, 2018 December 31, 2017 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 13,620 $ 2,769 $ 5,981 $ 994 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 13,620 $ 2,769 $ 5,981 $ 994 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (757 ) (757 ) (232 ) (232 ) Collateral posted (12,863 ) (2,007 ) (5,371 ) (745 ) Net credit exposure $ — $ 5 $ 378 $ 17 As of September 30, 2018, the counterparties posted collateral of $13.3 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	9 Months Ended
	Sep. 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. 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 initial public offering, 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 September 30, 2018, there were 1,355,545 shares available for future grants under the Omnibus Plan. During October 2018, the Company granted 5,000 shares of restricted common stock. These restricted shares will vest ratably over periods ranging between three and four years. The following table discloses the changes in restricted shares for the nine months ended September 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 September 30, 2018 194,455 $ 21.65 No restricted shares vested during the nine months ended September 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 nine months ended September 30, 2018 and 2017: Nine Months Ended September 30, 2018 2017 Total share-based compensation - restricted stock $ 638 $ 94 Income tax benefit 178 38 Unrecognized compensation expense 3,379 1,087 Weighted-average amortization period remaining 3.1 years 2.8 years The fair value of the unvested restricted stock awards at September 30, 2018 was $4.4 million. The Company maintained a nonqualified, share-based, stock option plan adopted prior to recapitalization (“MBG Plan”). There were no options granted or exercised under this plan during the year ended December 31, 2017. At the time of the Company’s reincorporation in Delaware in June 2017, the Board of Directors cancelled the MBG Plan and all the respective outstanding options were cancelled. In October 2014, the Company adopted the Byline Bancorp, Inc. Equity Incentive Plan (“BYB Plan”). The maximum number of shares available for grants under this plan was 2,476,122 shares. During 2016 and 2015, the Company granted options to purchase 212,400 and 1,634,568 shares, respectively, under this plan. The Company did not grant any stock options during the year ended December 31, 2017. In June 2017, the Board of Directors terminated the BYB Plan and no future grants can be made under this plan. Options to purchase a total of 1,654,272 shares remain outstanding under the BYB Plan at September 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 nine months ended September 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 (123,748 ) 11.79 $ 1,345 Forfeited (5,000 ) 16.25 Ending balance outstanding at September 30, 2018 1,654,272 $ 11.91 $ 17,855 6.9 Exercisable at September 30, 2018 1,487,672 $ 11.42 $ 16,780 6.8 A total of 123,748 stock options were exercised during the nine months ended September 30, 2018. During the nine months ended September 30, 2018, proceeds from the exercise of stock options were $1.5 million and related tax benefit was $297,000. There were no stock options exercised during the year ended December 31, 2017. A total of 307,163 stock options vested during the nine months ended September 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 nine months ended September 30, 2018 and 2017: Nine Months Ended September 30, 2018 2017 Total share-based compensation - stock options $ 510 $ 857 Income tax benefit 142 348 Unrecognized compensation expense 209 1,132 Weighted-average amortization period remaining 1.2 years 1.2 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 nine months ended September 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 (22,765 ) 10.59 $ 281 Forfeited — Ending balance outstanding at September 30, 2018 658,022 $ 11.28 $ 7,513 5.2 Exercisable at September 30, 2018 658,022 $ 11.28 $ 7,513 5.2 A total of 22,765 stock options were exercised during the nine months ended September 30, 2018. During the nine months ended September 30, 2018, proceeds from the exercise of stock options were $241,000 and related tax benefit was $64,000. All shares of restricted performance shares of First Evanston common stock (“restricted stock”) that were previously issued under and held by Participants in the FEB Plan prior to the Merger were converted into the right to receive the per share merger consideration in connection with the Merger and pursuant to the Merger Agreement. Accordingly, no shares of First Evanston restricted stock remain outstanding under the FEB Plan.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 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 2,312,294 and 1,798,223 shares of common stock were outstanding as of September 30, 2018 and 2017, respectively. There were 194,455 and 58,500 restricted stock awards outstanding at September 30, 2018 and 2017, respectively. The following represent the calculation of basic and diluted earnings per share for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Net income $ 14,536 $ 9,755 $ 24,072 $ 22,461 Less: Dividends on preferred shares 196 195 587 11,081 Net income available to common stockholders $ 14,340 $ 9,560 $ 23,485 $ 11,380 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 36,042,914 29,246,900 32,341,087 26,194,025 Incremental shares 915,295 505,431 947,570 503,816 Weighted-average common stock outstanding (dilutive) 36,958,209 29,752,331 33,288,657 26,697,841 Basic earnings per common share $ 0.40 $ 0.33 $ 0.73 $ 0.43 Diluted earnings per common share $ 0.39 $ 0.32 $ 0.71 $ 0.43

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Stockholders' Equity	Note 20—Stockholders’ Equity A summary of the Company’s preferred and common stock at September 30, 2018 and December 31, 2017 is as follows: September 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 36,279,600 29,317,298 Shares outstanding 36,279,600 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 September 30, 2018, the Company declared and paid dividends on the Series B preferred stock of $196,000, compared to $195,000 for the three months ended September 30, 2017. For the nine months ended September 30, 2018, the Company declared and paid dividends on the Series B preferred stock of $587,000, compared to $580,000 for the nine months ended September 30, 2017.

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 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 nine months ended September 30, 2018 and September 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 income (loss), net of tax (605 ) 3,325 2,720 Balance, September 30, 2017 $ 1,628 $ (6,176 ) $ (4,548 ) 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 4,213 (10,725 ) (6,512 ) Balance, September 30, 2018 $ 7,813 $ (20,175 ) $ (12,362 )

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 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 September 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. On October 17, 2018, we entered a definitive merger agreement with Oak Park River Forest Bankshares, Inc. (which we refer to as “Oak Park River Forest”), the parent company of Community Bank of Oak Park River Forest, to which the Company will acquire Oak Park River Forest through the merger of Oak Park River Forest with and into the Company, followed immediately by the merger of Community Bank of Oak Park River Forest with and into Byline Bank. At such time, Community Bank of Oak Park River Forest’s banking offices will become banking offices of the Bank. The above described merger agreements are anticipated to be completed during the first half of 2019, subject to the satisfaction or waiver of the conditions included in the merger agreement. No other subsequent events were identified that would have required a change to the consolidated financial statements or disclosure in the notes to the consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity. 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), and 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 (loss) 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. Fair Value Measurement (Topic 820) In August 2018, FASB issued ASU No. 2018-13, Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement . The amendments in this ASU modify the disclosure requirements on fair value measurements in Topic 820. The amendments remove the disclosure requirements for the amount and reasons for transfers between Level 1 and Level 2 securities of the fair value hierarchy, the policy for timing of transfers between levels, and the valuation processes for Level 3 fair value measurement. The amendments modify the disclosure requirements as follows: in lieu of a rollforward for Level 3 fair value measurements, a nonpublic entity is required to disclose transfers into and out of Level 3 of the fair value hierarchy and purchases and issues of Level 3 assets and liabilities; for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The amendments add the following disclosure requirements: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. This guidance is effective for annual and interim periods beginning after December 15, 2019. 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 early adopted these amendments in 2018, which did not have a material impact on the Company’s Consolidated Financial Statements.

Basis of Presentation (Tables)

Basis of Presentation (Tables)	9 Months Ended
	Sep. 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)	9 Months Ended
	Sep. 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 nine months ended September 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 Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Total revenues (net interest income and non-interest income) $ 63,736 $ 56,188 $ 183,564 $ 167,812 Net income $ 14,726 $ 12,553 $ 37,737 $ 31,626 Earnings per share—basic $ 0.40 $ 0.34 $ 1.03 $ 0.62 Earnings per share—diluted $ 0.39 $ 0.34 $ 1.01 $ 0.61

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 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 September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 55,717 $ — $ (384 ) $ 55,333 U.S. Government agencies 148,892 2 (2,274 ) 146,620 Obligations of states, municipalities, and political subdivisions 62,389 24 (1,186 ) 61,227 Residential mortgage-backed securities Agency 301,515 — (16,067 ) 285,448 Non-agency 75,763 — (2,200 ) 73,563 Commercial mortgage-backed securities Agency 75,380 154 (3,547 ) 71,987 Non-agency 31,535 — (1,489 ) 30,046 Small Business Administration mortgage-backed securities 26,715 9 — 26,724 Corporate securities 37,685 251 (523 ) 37,413 Other securities 4,611 2,591 (155 ) 7,047 Total $ 820,202 $ 3,031 $ (27,825 ) $ 795,408 September 30, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,885 $ 14 $ (545 ) $ 23,354 Residential mortgage-backed securities Agency 42,668 40 (948 ) 41,760 Non-agency 36,130 — (1,311 ) 34,819 Total $ 102,683 $ 54 $ (2,804 ) $ 99,933 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 September 30, 2018 and December 31, 2017 are summarized as follows: Less than 12 Months 12 Months or Longer Total September 30, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 23 $ 42,524 $ (196 ) $ 9,814 $ (188 ) $ 52,338 $ (384 ) U.S. Government agencies 52 92,091 (510 ) 52,536 (1,764 ) 144,627 (2,274 ) Obligations of states, municipalities and political subdivisions 133 40,567 (467 ) 14,693 (719 ) 55,260 (1,186 ) Residential mortgage-backed securities Agency 44 29,441 (886 ) 254,756 (15,181 ) 284,197 (16,067 ) Non-agency 9 69,533 (1,962 ) 4,029 (238 ) 73,562 (2,200 ) Commercial mortgage-backed securities Agency 8 7,181 (116 ) 53,213 (3,431 ) 60,394 (3,547 ) Non-agency 5 — — 30,046 (1,489 ) 30,046 (1,489 ) Corporate securities 12 19,286 (282 ) 4,691 (241 ) 23,977 (523 ) Other securities 1 — — 2,819 (155 ) 2,819 (155 ) Total 287 $ 300,623 $ (4,419 ) $ 426,597 $ (23,406 ) $ 727,220 $ (27,825 ) Less than 12 Months 12 Months or Longer Total September 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 29 $ 18,197 $ (444 ) $ 3,600 $ (101 ) $ 21,797 $ (545 ) Residential mortgage-backed securities Agency 18 24,101 (388 ) 14,465 (560 ) 38,566 (948 ) Non-agency 7 30,927 (1,105 ) 3,891 (206 ) 34,818 (1,311 ) Total 54 $ 73,225 $ (1,937 ) $ 21,956 $ (867 ) $ 95,181 $ (2,804 ) 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 nine months ended September 30, 2018 For the Three Months Ended For the Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Proceeds $ — $ — $ 544 $ 8 Gross gains — — 4 8 Gross losses — — — —
Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity	At September 30, 2018, the Amortized Cost Fair Value Available-for-sale Due in one year or less $ 66,866 $ 66,842 Due from one to five years 179,535 176,765 Due from five to ten years 44,295 43,365 Due after ten years 14,525 14,312 Mortgage-backed securities 510,908 487,768 Other securities with no defined maturity 4,073 6,356 Total $ 820,202 $ 795,408 Held-to-maturity Due from one to five years $ 5,067 $ 4,966 Due from five to ten years 10,616 10,349 Due after ten years 8,202 8,039 Mortgage-backed securities 78,798 76,579 Total $ 102,683 $ 99,933

Loan and Lease Receivables (Tab

Loan and Lease Receivables (Tables)	9 Months Ended
	Sep. 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: September 30, December 31, 2018 2017 Commercial real estate $ 1,272,208 $ 891,971 Residential real estate 705,132 577,123 Construction, land development, and other land 182,727 105,996 Commercial and industrial 1,095,946 522,254 Installment and other 12,150 4,182 Lease financing receivables 185,540 174,165 Total loans and leases 3,453,703 2,275,691 Net unamortized deferred fees and costs (1,418 ) (1,720 ) Initial direct costs 3,517 3,521 Allowance for loan and lease losses (23,424 ) (16,706 ) Net loans and leases $ 3,432,378 $ 2,260,786 September 30, December 31, 2018 2017 Lease financing receivables Net minimum lease payments $ 201,938 $ 188,986 Unguaranteed residual values 1,630 1,644 Unearned income (18,028 ) (16,465 ) Total lease financing receivables 185,540 174,165 Initial direct costs 3,517 3,521 Lease financial receivables before allowance for lease losses $ 189,057 $ 177,686
Summary of Minimum Annual Lease Payments for Lease Financing Receivables	The minimum Minimum Lease Payments 2018 $ 17,443 2019 69,639 2020 53,597 2021 34,663 2022 19,821 Thereafter 6,775 Total $ 201,938
Summary of Balances for Each Respective Loan and Lease Category	The following September 30, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 619,767 $ 154,108 $ 498,329 $ 1,272,204 Residential real estate 445,717 120,963 138,516 705,196 Construction, land development, and other land 140,391 4,203 37,111 181,705 Commercial and industrial 696,750 14,436 384,260 1,095,446 Installment and other 7,729 458 4,007 12,194 Lease financing receivables 155,825 — 33,232 189,057 Total loans and leases $ 2,066,179 $ 294,168 $ 1,095,455 $ 3,455,802 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 September 30, 2018 December 31, 2017 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 169,149 $ 154,108 $ 235,898 $ 166,712 Residential real estate 123,542 120,963 207,660 144,562 Construction, land development, and other land 4,615 4,203 13,270 5,946 Commercial and industrial 23,467 14,436 18,333 10,008 Installment and other 1,126 458 1,819 462 Total acquired impaired loans $ 321,899 $ 294,168 $ 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 nine months ended September 30, 2018 and 2017: Three Months Ended Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Beginning balance $ 41,306 $ 37,619 $ 36,446 $ 36,868 Additions — — 3,566 — Accretion to interest income (5,665 ) (8,165 ) (17,227 ) (24,768 ) Reclassification from nonaccretable difference, net 2,507 6,901 15,363 24,255 Ending balance $ 38,148 $ 36,355 $ 38,148 $ 36,355
Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-Impaired Loans and Leases	The unpaid September 30, 2018 December 31, 2017 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 506,507 $ 498,329 $ 221,710 $ 211,359 Residential real estate 141,011 138,516 32,605 32,085 Construction, land development, and other land 39,694 37,111 1,926 1,845 Commercial and industrial 397,746 384,260 105,529 94,731 Installment and other 7,601 4,007 355 42 Lease financing receivables 34,706 33,232 37,476 36,357 Total acquired non-impaired loans and leases $ 1,127,265 $ 1,095,455 $ 399,601 $ 376,419

Allowance for Loan and Lease _2

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments (Tables)	9 Months Ended
	Sep. 30, 2018
Receivables [Abstract]
Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances	The following September 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 $ 6,453 $ 1,648 $ 332 $ 8,369 $ 30 $ 2,855 $ 19,687 Provisions 1,705 29 58 3,579 12 459 5,842 Charge-offs (736 ) — — (858 ) (4 ) (823 ) (2,421 ) Recoveries — — — 75 — 241 316 Ending balance $ 7,422 $ 1,677 $ 390 $ 11,165 $ 38 $ 2,732 $ 23,424 Nine months ended Beginning balance $ 4,794 $ 1,638 $ 222 $ 7,418 $ 41 $ 2,593 $ 16,706 Provisions 3,975 39 586 8,959 33 1,321 14,913 Charge-offs (1,347 ) — (418 ) (5,539 ) (36 ) (1,888 ) (9,228 ) Recoveries — — — 327 — 706 1,033 Ending balance $ 7,422 $ 1,677 $ 390 $ 11,165 $ 38 $ 2,732 $ 23,424 Ending balance: Individually evaluated for impairment $ 2,294 $ 70 $ — $ 4,044 $ 14 $ — $ 6,422 Collectively evaluated for impairment 3,413 1,150 390 6,301 21 2,732 14,007 Loans acquired with deteriorated credit quality 1,715 457 — 820 3 — 2,995 Total allowance for loan and lease losses $ 7,422 $ 1,677 $ 390 $ 11,165 $ 38 $ 2,732 $ 23,424 September 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 $ 13,612 $ 1,941 $ — $ 19,962 $ 14 $ — $ 35,529 Collectively evaluated for impairment 1,104,484 582,292 177,502 1,061,048 11,722 189,057 3,126,105 Loans acquired with deteriorated credit quality 154,108 120,963 4,203 14,436 458 — 294,168 Total loans and leases $ 1,272,204 $ 705,196 $ 181,705 $ 1,095,446 $ 12,194 $ 189,057 $ 3,455,802 September 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 $ 3,668 $ 1,835 $ 327 $ 5,689 $ 344 $ 2,106 $ 13,969 Provisions (releases) 1,577 52 (111 ) 1,440 13 929 3,900 Charge-offs (186 ) (161 ) — (763 ) (327 ) (862 ) (2,299 ) Recoveries — — — — — 410 410 Ending balance $ 5,059 $ 1,726 $ 216 $ 6,366 $ 30 $ 2,583 $ 15,980 Nine months ended Beginning balance $ 1,945 $ 2,483 $ 742 $ 4,196 $ 334 $ 1,223 $ 10,923 Provisions (releases) 3,591 (400 ) (526 ) 3,932 23 2,686 9,306 Charge-offs (477 ) (357 ) — (1,762 ) (327 ) (2,399 ) (5,322 ) Recoveries — — — — — 1,073 1,073 Ending balance $ 5,059 $ 1,726 $ 216 $ 6,366 $ 30 $ 2,583 $ 15,980 Ending balance: Individually evaluated for impairment $ 1,186 $ 176 $ — $ 1,585 $ 2 $ — $ 2,949 Collectively evaluated for impairment 1,844 1,237 155 3,389 10 2,583 9,218 Loans acquired with deteriorated credit quality 2,029 313 61 1,392 18 — 3,813 Total allowance for loan and lease losses $ 5,059 $ 1,726 $ 216 $ 6,366 $ 30 $ 2,583 $ 15,980 September 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 $ 14,928 $ 1,948 $ 565 $ 6,075 $ 2 $ — $ 23,518 Collectively evaluated for impairment 673,851 428,565 88,315 484,547 2,762 172,341 1,850,381 Loans acquired with deteriorated credit quality 173,106 152,149 5,424 11,433 488 — 342,600 Total loans and leases $ 861,885 $ 582,662 $ 94,304 $ 502,055 $ 3,252 $ 172,341 $ 2,216,499
Summary of Recorded Investment, Unpaid Principal Balance, and Related Allowance for Loans and Leases Considered Impaired	The following and September 30, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 8,439 $ 9,566 $ — Residential real estate 1,689 1,655 — Commercial and industrial 9,971 11,694 — With an allowance recorded Commercial real estate 5,173 5,419 2,294 Residential real estate 252 253 70 Commercial and industrial 9,991 10,535 4,044 Installment and other 14 14 14 Total impaired loans $ 35,529 $ 39,136 $ 6,422 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 nine months ended as follows: September 30, 2018 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 9,441 $ 232 Residential real estate 1,910 24 Construction, land development and other land — 15 Commercial and industrial 8,018 194 With an allowance recorded Commercial real estate 5,022 16 Residential real estate 330 3 Commercial and industrial 9,047 484 Installment and other 14 9 Total impaired loans $ 33,782 $ 977 September 30, 2017 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 10,605 $ 419 Residential real estate 1,698 33 Construction, land development and other land 269 2 Commercial and industrial 2,391 253 With an allowance recorded Commercial real estate 1,043 287 Residential real estate 444 4 Construction, land development and other land 19 — Commercial and industrial 1,673 500 Installment and other 213 11 Total impaired loans $ 18,355 $ 1,509
Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation	The following September 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 $ 1,017,225 $ 544,986 $ 159,712 $ 915,027 $ 11,696 $ 187,623 $ 2,836,269 Watch 71,382 30,287 14,691 128,597 — 100 245,057 Special Mention 14,508 5,729 3,099 15,654 13 856 39,859 Substandard 14,981 3,231 — 21,732 27 317 40,288 Doubtful — — — — — 161 161 Loss — — — — — — — Total $ 1,118,096 $ 584,233 $ 177,502 $ 1,081,010 $ 11,736 $ 189,057 $ 3,161,634 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 September 30, 2018 and December 31, 2017: September 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 $ 5,452 $ 1,282 $ — $ 12,553 $ 19,287 $ 1,098,809 $ 1,118,096 Residential real estate 434 196 — 1,631 2,261 581,972 584,233 Construction, land development, and other land — — — — — 177,502 177,502 Commercial and industrial 3,600 2,361 291 13,958 20,210 1,060,800 1,081,010 Installment and other 34 1 — 23 58 11,678 11,736 Lease financing receivables 1,511 624 — 478 2,613 186,444 189,057 Total $ 11,031 $ 4,464 $ 291 $ 28,643 $ 44,429 $ 3,117,205 $ 3,161,634 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
Summary of TDR's by Loan Category	The tables below present TDRs by loan category as September 30, 2018 and December 31, 2017: September 30, 2018 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 3 $ 914 $ 914 $ — $ 113 Commercial and industrial 2 193 193 — 107 Residential real estate 1 123 123 — — Total accruing 6 1,230 1,230 — 220 Non-accruing: Commercial real estate 8 2,678 2,637 41 420 Commercial and industrial 4 6,593 4,722 1,871 1,155 Total non-accruing 12 9,271 7,359 1,912 1,575 Total troubled debt restructurings 18 10,501 8,589 1,912 1,795 December 31, 2017 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 3 $ 912 $ 912 $ — $ — Residential real estate 1 149 149 — — Total accruing 4 1,061 1,061 — — Non-accruing: Commercial real estate 2 743 743 — 111 Commercial and industrial 3 1,246 759 487 246 Residential real estate 1 67 67 — — Total non-accruing 6 2,056 1,569 487 357 Total troubled debt restructurings 10 3,117 2,630 487 357
Summary of Loans Modified as Troubled Debt Restructurings	Loans modified three and nine months ended September 30, 2018 For the Three Months Ended For the Nine Months Ended September 30, September 30, 2018 2017 2018 2017 Accruing: Beginning balance $ 1,238 $ 981 $ 1,061 $ 602 Additions — 673 37 1,017 Net payments (8 ) (23 ) (56 ) (59 ) Net transfers from non-accrual — — 188 71 Ending balance 1,230 1,631 1,230 1,631 Non-accruing: Beginning balance 5,776 470 1,570 552 Additions 1,667 194 7,123 194 Net payments (84 ) (8 ) (1,002 ) (19 ) Charge-offs — — (144 ) — Net transfers to accrual — — (188 ) (71 ) Ending balance 7,359 656 7,359 656 Total troubled debt restructurings 8,589 2,287 8,589 2,287

Servicing Assets (Tables)

Servicing Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Transfers And Servicing [Abstract]
Activity for Servicing Assets and Related Changes in Fair Value	Activity for the three and nine months ended September 30, 2018 is Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 21,587 $ 21,424 $ 21,400 $ 21,091 Additions, net 1,489 1,727 5,680 4,675 Changes in fair value (2,402 ) (1,482 ) (6,406 ) (4,097 ) Ending balance $ 20,674 $ 21,669 $ 20,674 $ 21,669
Unpaid Principal Balances of Loans Serviced for Others	The unpaid as of September 30, 2018 and December 31, 2017 were as follows: September 30, December 31, 2018 2017 Loan portfolios serviced for: SBA guaranteed loans $ 1,135,871 $ 1,021,143 USDA guaranteed loans 86,417 91,758 Total $ 1,222,288 $ 1,112,901

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	9 Months Ended
	Sep. 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 three and nine months ended September 30, 2018 and 2017. Three Months Ended September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Beginning balance $ 6,402 $ 12,684 $ 10,626 $ 16,570 Net additions to OREO 307 3,417 1,527 6,069 Dispositions of OREO (1,519 ) (1,989 ) (6,750 ) (8,045 ) Valuation adjustments (299 ) (253 ) (512 ) (735 ) Ending balance $ 4,891 $ 13,859 $ 4,891 $ 13,859

Goodwill, Core Deposit Intang_2

Goodwill, Core Deposit Intangible and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets	The following tables summarize the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the three and nine months ended September 30, 2018 and 2017: Nine Months Ended September 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 — (3,685 ) (89 ) — (2,293 ) — Ending balance $ 127,536 $ 32,095 $ 3,127 $ 51,975 $ 17,483 $ — Accumulated amortization N/A $ 17,151 $ 89 N/A $ 12,703 N/A Weighted average remaining amortization period N/A 7.1 Years 11.7 Years N/A 5.8 Years N/A Three Months Ended September 30, 2018 2017 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 127,536 $ 33,917 $ 3,194 $ 51,975 $ 18,247 $ — Additions — — — — — — Amortization — (1,822 ) (67 ) — (764 ) — Ending balance $ 127,536 $ 32,095 $ 3,127 $ 51,975 $ 17,483 $ — Accumulated amortization N/A $ 17,151 $ 89 N/A $ 12,703 N/A Weighted average remaining amortization period N/A 7.1 Years 11.7 Years N/A 5.8 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 September 30, 2018: Estimated Amortization 2018 $ 1,807 2019 6,945 2020 6,477 2021 6,026 2022 5,578 Thereafter 8,415 Total $ 35,248

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2018
Deposits [Abstract]
Schedule of Deposits	The composition of deposits was as follows as of September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 Non-interest bearing demand deposits $ 1,175,222 $ 760,887 Interest bearing checking accounts 317,145 186,611 Money market demand accounts 661,271 349,862 Other savings 476,879 437,212 Time deposits (below $250,000) 916,014 627,255 Time deposits ($250,000 and above) 194,236 81,502 Total deposits $ 3,740,767 $ 2,443,329

Federal Home Loan Bank Advanc_2

Federal Home Loan Bank Advances (Tables)	9 Months Ended
	Sep. 30, 2018
Federal Home Loan Banks [Abstract]
Summary of FHLB Advances	The following September 30, December 31, 2018 2017 Federal Home Loan Bank advances $ 425,000 $ 361,506 Weighted average cost 2.30 % 1.49 %

Other Borrowings (Tables)

Other Borrowings (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Summary of Other Borrowings	The following is a summary of the Company’s other borrowings as of September 30, 2018 and December 31, 2017: September 30, December 31, 2018 2017 Securities sold under agreements to repurchase $ 24,446 $ 31,187 Line of credit — — Total $ 24,446 $ 31,187
Summary of Short-term Credit Lines Available for Use	The following September 30, December 31, 2018 2017 Federal Reserve Bank of Chicago discount window line $ 310,345 $ 144,248 Available federal funds lines 55,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures (Tables)	9 Months Ended
	Sep. 30, 2018
Debt Disclosure [Abstract]
Junior Subordinated Debentures by Issuance	At September 30, 2018 and December 31, 2017, the Name of Trust Aggregate Principal Amount September 30, 2018 Aggregate Principal Amount December 31, 2017 Stated Maturity Contractual Rate at September 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 4.11 % Three-month LIBOR + 1.78% Total liability, at par 46,500 36,500 Discount (9,885 ) (8,853 ) Total liability, at carrying value $ 36,615 $ 27,647

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	9 Months Ended
	Sep. 30, 2018
Commitments And Contingencies Disclosure [Abstract]
Summary of Minimum Annual Rental Commitments for Operating Leases	The minimum Minimum Commitments 2018 $ 944 2019 3,316 2020 2,777 2021 2,450 2022 1,488 Thereafter 3,167 Total $ 14,142
Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments	The following September 30, 2018 and December 31, 2017 September 30, December 31, 2018 2017 Fixed Rate Variable Rate Fixed Rate Variable Rate Commitments to extend credit $ 74,062 $ 944,577 $ 55,924 $ 467,429 Letters of credit 1,985 24,105 1,226 3,337 Total $ 76,047 $ 968,682 $ 57,150 $ 470,766

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 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 September 30, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 55,333 $ 55,333 $ — $ — U.S. Government agencies 146,620 — 146,620 — Obligations of states, municipalities, and political subdivisions 61,227 — 60,538 689 Residential mortgage-backed securities Agency 285,448 — 285,448 — Non-agency 73,563 — 73,563 — Commercial mortgage-backed securities Agency 71,987 — 71,987 — Non-agency 30,046 — 30,046 — Small Business Administration mortgage-backed securities 26,724 — 26,724 — Corporate securities 37,413 — 37,413 — Other securities 7,047 2,819 3,536 692 Servicing assets 20,674 — — 20,674 Derivative assets 13,620 — 13,620 — Financial liabilities Derivative liabilities 2,769 — 2,769 — 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): Nine Months Ended September 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 — — 5,680 4,675 Amortization 4 3 — — Change in unrealized gain 11 6 — — Changes in fair value — — (6,406 ) (4,097 ) Balance, end of period $ 1,381 $ 1,089 $ 20,674 $ 21,669
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 2.1%—25.9% 10.9 % Decrease Discount rate 7.7%—24.4% 14.9 % Decrease Expected weighted average loan life 0.8—10.8 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 September 30, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 11,318 $ — $ — $ 11,318 Residential real estate 1,871 — — 1,871 Construction, land development, and other land — — — — Commercial and industrial 15,918 — — 15,918 Installment and other — — — — Assets held for sale 8,343 — — 8,343 Other real estate owned 4,891 — — 4,891 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
Estimated Fair Values of Financial Instruments	The estimated September 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 $ 25,162 $ 25,162 $ 19,404 $ 19,404 Interest bearing deposits with other banks 2 119,594 119,594 38,945 38,945 Securities held-to-maturity 2 102,683 99,933 117,163 117,277 Other restricted stock 2 19,202 19,202 16,343 16,343 Loans held for sale 3 8,737 9,707 5,212 5,851 Loans and lease receivables, net 3 3,432,378 3,356,116 2,260,786 2,240,235 Accrued interest receivable 3 11,331 11,331 7,670 7,670 Financial liabilities Non-interest bearing deposits 2 1,175,222 1,175,222 760,887 760,887 Interest bearing deposits 2 2,565,545 2,561,465 1,682,442 1,678,535 Accrued interest payable 2 2,971 2,971 1,306 1,306 Line of credit 2 — — — — Federal Home Loan Bank advances 2 425,000 425,000 361,506 361,500 Securities sold under repurchase agreement 2 24,446 24,446 31,187 31,187 Junior subordinated debentures 3 36,615 42,693 27,647 33,907

Derivative Instruments and He_2

Derivative Instruments and Hedge Activities (Tables)	9 Months Ended
	Sep. 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 September 30, 2018 and December 31, 2017: September 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 $ 10,883 $ — $ 250,000 $ 5,030 $ 38 Derivatives not designated as hedging instruments Other interest rate swaps 236,916 2,737 2,766 94,726 951 956 Other credit derivatives 4,504 — 3 — — — Total derivatives $ 491,420 $ 13,620 $ 2,769 $ 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 nine months ended: September 30, 2018 September 30, 2017 Amount of Gain (Loss) Recognized in OCI (Effective Portion) Amount of Gain (Loss) 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 Gain (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 $ 6,702 $ 863 $ — $ (1,408 ) $ (426 ) $ —
Summary of Other Interest Rate Swaps	The following table reflects other interest rate swaps as of September 30, 2018 Notional amounts $ 236,916 Derivative assets fair value 2,737 Derivative liabilities fair value 2,766 Weighted average pay rates 4.64 % Weighted average receive rates 4.19 % Weighted average maturity 5.7 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: September 30, 2018 December 31, 2017 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 13,620 $ 2,769 $ 5,981 $ 994 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 13,620 $ 2,769 $ 5,981 $ 994 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (757 ) (757 ) (232 ) (232 ) Collateral posted (12,863 ) (2,007 ) (5,371 ) (745 ) Net credit exposure $ — $ 5 $ 378 $ 17 As of September 30, 2018, the counterparties posted collateral of $13.3 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 September 30, 2018: Notional amounts $ 250,000 Derivative assets fair value 10,883 Derivative liabilities fair value — Weighted average pay rates 1.67 % Weighted average receive rates 2.33 % Weighted average maturity 3.4 years

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 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 nine months ended September 30, 2018 and 2017: Nine Months Ended September 30, 2018 2017 Total share-based compensation - stock options $ 510 $ 857 Income tax benefit 142 348 Unrecognized compensation expense 209 1,132 Weighted-average amortization period remaining 1.2 years 1.2 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 nine months ended September 30, 2018 and 2017: Nine Months Ended September 30, 2018 2017 Total share-based compensation - restricted stock $ 638 $ 94 Income tax benefit 178 38 Unrecognized compensation expense 3,379 1,087 Weighted-average amortization period remaining 3.1 years 2.8 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 nine months ended September 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 September 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 nine months ended September 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 (123,748 ) 11.79 $ 1,345 Forfeited (5,000 ) 16.25 Ending balance outstanding at September 30, 2018 1,654,272 $ 11.91 $ 17,855 6.9 Exercisable at September 30, 2018 1,487,672 $ 11.42 $ 16,780 6.8
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 nine months ended September 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 (22,765 ) 10.59 $ 281 Forfeited — Ending balance outstanding at September 30, 2018 658,022 $ 11.28 $ 7,513 5.2 Exercisable at September 30, 2018 658,022 $ 11.28 $ 7,513 5.2

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 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 September 30, Nine Months Ended September 30, 2018 2017 2018 2017 Net income $ 14,536 $ 9,755 $ 24,072 $ 22,461 Less: Dividends on preferred shares 196 195 587 11,081 Net income available to common stockholders $ 14,340 $ 9,560 $ 23,485 $ 11,380 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 36,042,914 29,246,900 32,341,087 26,194,025 Incremental shares 915,295 505,431 947,570 503,816 Weighted-average common stock outstanding (dilutive) 36,958,209 29,752,331 33,288,657 26,697,841 Basic earnings per common share $ 0.40 $ 0.33 $ 0.73 $ 0.43 Diluted earnings per common share $ 0.39 $ 0.32 $ 0.71 $ 0.43

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2018
Equity [Abstract]
Summary of Preferred and Common Stock	A summary of the Company’s preferred and common stock at September 30, 2018 and December 31, 2017 is as follows: September 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 36,279,600 29,317,298 Shares outstanding 36,279,600 29,317,298

Consolidated Statements of Ch_3

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 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 nine months ended September 30, 2018 and September 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 income (loss), net of tax (605 ) 3,325 2,720 Balance, September 30, 2017 $ 1,628 $ (6,176 ) $ (4,548 ) 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 4,213 (10,725 ) (6,512 ) Balance, September 30, 2018 $ 7,813 $ (20,175 ) $ (12,362 )

Basis of Presentation - Schedul

Basis of Presentation - Schedule of Aforementioned Revisions to Consolidated Statements of Financial Condition (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Error Corrections And Prior Period Adjustments Restatement [Line Items]
Goodwill	$ 127,536	$ 127,536	$ 54,562	$ 51,975	$ 51,975	$ 51,975
Deferred tax assets, net	42,287		47,376
Total assets	$ 4,917,409		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 Pr_2

Recently Issued Accounting Pronouncements - Additional Information (Details)	9 Months Ended
	Sep. 30, 2018USD ($)
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)	$ (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 (loss)	$ 763,000

Acquisition of a Business - Add

Acquisition of a Business - Additional Information (Details) - USD ($)	May 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Business Acquisition [Line Items]
Goodwill		$ 127,536,000	$ 127,536,000	$ 54,562,000	$ 51,975,000	$ 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		$ 1,700,000
Core system conversion expenses		$ 9,200,000

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	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Consideration paid
Goodwill		$ 127,536	$ 127,536	$ 54,562	$ 51,975	$ 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 - S_2

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 - S_3

Acquisition of a Business - Summary of Acquired Non-Impaired Loans as of Acquisition Date (Details) $ in Thousands	May 31, 2018USD ($)
Business Combinations [Abstract]
Fair value	$ 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 - S_4

Acquisition of a Business - Summary of Unaudited Pro Forma Information for Results of Operations (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Business Combinations [Abstract]
Total revenues (net interest income and non-interest income)	$ 63,736	$ 56,188	$ 183,564	$ 167,812
Net income	$ 14,726	$ 12,553	$ 37,737	$ 31,626
Earnings per share—basic	$ 0.40	$ 0.34	$ 1.03	$ 0.62
Earnings per share—diluted	$ 0.39	$ 0.34	$ 1.01	$ 0.61

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 820,202	$ 593,167
Available-for-sale Securities, Gross Unrealized Gains	3,031	2,486
Available-for-sale Securities, Gross Unrealized Losses	(27,825)	(12,417)
Available-for-sale Securities, Fair Value	795,408	583,236
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	55,717	14,999
Available-for-sale Securities, Gross Unrealized Losses	(384)	(136)
Available-for-sale Securities, Fair Value	55,333	14,863
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	148,892	54,248
Available-for-sale Securities, Gross Unrealized Gains	2
Available-for-sale Securities, Gross Unrealized Losses	(2,274)	(1,290)
Available-for-sale Securities, Fair Value	146,620	52,958
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	62,389	33,405
Available-for-sale Securities, Gross Unrealized Gains	24	100
Available-for-sale Securities, Gross Unrealized Losses	(1,186)	(335)
Available-for-sale Securities, Fair Value	61,227	33,170
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	301,515	315,103
Available-for-sale Securities, Gross Unrealized Losses	(16,067)	(7,646)
Available-for-sale Securities, Fair Value	285,448	307,457
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	75,763	39,485
Available-for-sale Securities, Gross Unrealized Gains		104
Available-for-sale Securities, Gross Unrealized Losses	(2,200)	(75)
Available-for-sale Securities, Fair Value	73,563	39,514
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	75,380	70,964
Available-for-sale Securities, Gross Unrealized Gains	154	45
Available-for-sale Securities, Gross Unrealized Losses	(3,547)	(1,966)
Available-for-sale Securities, Fair Value	71,987	69,043
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	31,535	31,763
Available-for-sale Securities, Gross Unrealized Losses	(1,489)	(792)
Available-for-sale Securities, Fair Value	30,046	30,971
Small Business Administration Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	26,715
Available-for-sale Securities, Gross Unrealized Gains	9
Available-for-sale Securities, Fair Value	26,724
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	37,685	29,573
Available-for-sale Securities, Gross Unrealized Gains	251	507
Available-for-sale Securities, Gross Unrealized Losses	(523)	(104)
Available-for-sale Securities, Fair Value	37,413	29,976
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	4,611	3,627
Available-for-sale Securities, Gross Unrealized Gains	2,591	1,730
Available-for-sale Securities, Gross Unrealized Losses	(155)	(73)
Available-for-sale Securities, Fair Value	$ 7,047	$ 5,284

Securities - Summary of Amort_2

Securities - Summary of Amortized Cost and Fair Values of Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	$ 102,683	$ 117,163
Held-to-maturity Securities, Gross Unrealized Gains	54	450
Held-to-maturity Securities, Gross Unrealized Losses	(2,804)	(336)
Securities held-to-maturity, fair value	99,933	117,277
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	23,885	24,030
Held-to-maturity Securities, Gross Unrealized Gains	14	197
Held-to-maturity Securities, Gross Unrealized Losses	(545)	(82)
Securities held-to-maturity, fair value	23,354	24,145
Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	42,668	53,731
Held-to-maturity Securities, Gross Unrealized Gains	40	79
Held-to-maturity Securities, Gross Unrealized Losses	(948)	(203)
Securities held-to-maturity, fair value	41,760	53,607
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	36,130	39,402
Held-to-maturity Securities, Gross Unrealized Gains		174
Held-to-maturity Securities, Gross Unrealized Losses	(1,311)	(51)
Securities held-to-maturity, fair value	$ 34,819	$ 39,525

Securities - Additional Informa

Securities - Additional Information (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2018USD ($)Security	Sep. 30, 2017USD ($)	Sep. 30, 2018USD ($)Security	Sep. 30, 2017USD ($)	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	0	$ 0	4,000	$ 8,000
Carrying amount of securities pledged as collateral	$ 261,100,000		$ 261,100,000		$ 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	227,600,000		227,600,000		99,300,000
Customer Repurchase Agreements
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral	$ 33,500,000		$ 33,500,000		$ 34,800,000
Available-for-sale Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security	287		287
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	Sep. 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	287	101
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 300,623	$ 39,896
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(4,419)	(407)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	426,597	455,688
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(23,406)	(12,010)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	727,220	495,584
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (27,825)	$ (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	23	5
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 42,524	$ 4,998
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(196)	(2)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	9,814	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	52,338	14,863
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (384)	$ (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	52	9
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 92,091	$ 992
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(510)	(7)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	52,536	51,966
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(1,764)	(1,283)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	144,627	52,958
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (2,274)	$ (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	133	29
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 40,567	$ 16,059
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(467)	(137)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	14,693	4,453
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(719)	(198)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	55,260	20,512
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,186)	$ (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	$ 29,441	$ 15,441
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(886)	(181)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	254,756	292,016
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(15,181)	(7,465)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	284,197	307,457
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (16,067)	$ (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	9	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 69,533
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1,962)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,029	$ 4,565
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(238)	(75)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	73,562	4,565
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (2,200)	$ (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	$ 7,181
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(116)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	53,213	$ 57,442
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(3,431)	(1,966)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	60,394	57,442
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (3,547)	$ (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	$ 30,046	$ 30,971
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(1,489)	(792)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	30,046	30,971
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,489)	$ (792)
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	12	3
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 19,286	$ 2,406
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(282)	(80)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	4,691	2,489
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(241)	(24)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	23,977	4,895
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (523)	$ (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	$ 2,819	$ 1,921
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(155)	(73)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	2,819	1,921
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (155)	$ (73)

Securities - Summary of Gross_2

Securities - Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Held-to-maturity (Details) $ in Thousands	Sep. 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	$ 73,225	$ 42,211
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1,937)	(155)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	21,956	13,865
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(867)	(181)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	95,181	56,076
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (2,804)	$ (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	29	12
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 18,197	$ 7,409
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(444)	(38)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	3,600	1,548
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(101)	(44)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	21,797	8,957
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (545)	$ (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	18	13
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 24,101	$ 24,344
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(388)	(107)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	14,465	7,935
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(560)	(96)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	38,566	32,279
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (948)	$ (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	$ 30,927	$ 10,458
Held-to-maturity Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1,105)	(10)
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	3,891	4,382
Held-to-maturity Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(206)	(41)
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Fair Value	34,818	14,840
Held-to-maturity Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (1,311)	$ (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	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Available For Sale Securities Gross Realized Gain Loss [Abstract]
Proceeds	$ 544	$ 8
Gross gains	$ 4	$ 8

Securities - Schedule of Amorti

Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 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	$ 66,866
Available-for-sale Securities, Due from one to five years, Amortized Cost	179,535
Available-for-sale Securities, Due from five to ten years, Amortized Cost	44,295
Available-for-sale Securities, Due after ten years, Amortized Cost	14,525
Available-for-sale Securities, Amortized Cost	820,202	$ 593,167
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Due from one to five years, Amortized Cost	5,067
Held-to-maturity Securities, Due from five to ten years, Amortized Cost	10,616
Held-to-maturity Securities, Due after ten years, Amortized Cost	8,202
Held-to-maturity Securities, Amortized Cost	102,683	117,163
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Due in one year or less, Fair Value	66,842
Available-for-sale Securities, Due from one to five years, Fair Value	176,765
Available-for-sale Securities, Due from five to ten years, Fair Value	43,365
Available-for-sale Securities, Due after ten years, Fair Value	14,312
Total	795,408	583,236
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Due from one to five years, Fair Value	4,966
Held-to-maturity Securities, Due from five to ten years, Fair Value	10,349
Held-to-maturity Securities, Due after ten years, Fair Value	8,039
Total	99,933	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	510,908
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Mortgage-backed securities, Amortized Cost	78,798
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	487,768
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Mortgage-backed securities, Fair Value	76,579
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	4,611	3,627
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	6,356
Total	$ 7,047	$ 5,284

Loan and Lease Receivables - Sc

Loan and Lease Receivables - Schedule of Outstanding Loan and Lease Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,453,703		$ 2,275,691
Net unamortized deferred fees and costs	(1,418)		(1,720)
Initial direct costs	3,517		3,521
Allowance for loan and lease losses	(23,424)	$ (19,687)	(16,706)	$ (15,980)	$ (13,969)	$ (10,923)
Net loans and leases	3,432,378		2,260,786
Lease financing receivables
Net minimum lease payments	201,938		188,986
Unguaranteed residual values	1,630		1,644
Unearned income	(18,028)		(16,465)
Total lease financing receivables	185,540		174,165
Initial direct costs	3,517		3,521
Lease financial receivables before allowance for lease losses	189,057		177,686
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,272,208		891,971
Allowance for loan and lease losses	(7,422)	(6,453)	(4,794)	(5,059)	(3,668)	(1,945)
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	705,132		577,123
Allowance for loan and lease losses	(1,677)	(1,648)	(1,638)	(1,726)	(1,835)	(2,483)
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	182,727		105,996
Allowance for loan and lease losses	(390)	(332)	(222)	(216)	(327)	(742)
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,095,946		522,254
Allowance for loan and lease losses	(11,165)	(8,369)	(7,418)	(6,366)	(5,689)	(4,196)
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,150		4,182
Allowance for loan and lease losses	(38)	(30)	(41)	(30)	(344)	(334)
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	185,540		174,165
Allowance for loan and lease losses	$ (2,732)	$ (2,855)	$ (2,593)	$ (2,583)	$ (2,106)	$ (1,223)

Loan and Lease Receivables - Ad

Loan and Lease Receivables - Additional Information (Details) - USD ($)	Sep. 30, 2018	Jun. 30, 2018	May 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,453,703,000			$ 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	23,424,000	$ 19,687,000		16,706,000	$ 15,980,000	$ 13,969,000	$ 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	3,000,000			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	12,150,000			4,182,000
Overdraft deposits reclassified as loans	1,100,000			617,000
Allowance for loan and lease losses	38,000	$ 30,000		41,000	$ 30,000	$ 344,000	$ 334,000
U.S. Government Guaranteed Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 101,900,000			$ 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	Sep. 30, 2018USD ($)
Receivables [Abstract]
2,018	$ 17,443
2,019	69,639
2,020	53,597
2,021	34,663
2,022	19,821
Thereafter	6,775
Total	$ 201,938

Loan and Lease Receivables - _2

Loan and Lease Receivables - Summary of Balances for Each Respective Loan and Lease Category (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,455,802	$ 2,277,492	$ 2,216,499
Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	2,066,179	1,573,383
Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	294,168	327,690
Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,095,455	376,419
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,272,204	891,693	861,885
Commercial Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	619,767	513,622
Commercial Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	154,108	166,712
Commercial Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	498,329	211,359
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	705,196	577,218	582,662
Residential Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	445,717	400,571
Residential Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	120,963	144,562
Residential Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	138,516	32,085
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	181,705	105,429	94,304
Construction, Land Development, and Other Land | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	140,391	97,638
Construction, Land Development, and Other Land | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	4,203	5,946
Construction, Land Development, and Other Land | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	37,111	1,845
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,095,446	521,238	502,055
Commercial and Industrial | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	696,750	416,499
Commercial and Industrial | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	14,436	10,008
Commercial and Industrial | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	384,260	94,731
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	12,194	4,228	3,252
Installment and Other | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	7,729	3,724
Installment and Other | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	458	462
Installment and Other | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	4,007	42
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	189,057	177,686	$ 172,341
Lease Financing Receivables | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	155,825	141,329
Lease Financing Receivables | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 33,232	$ 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 ($)	Sep. 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 - _3

Loan and Lease Receivables - Summary of Outstanding Balance and Carrying Amount of All Acquired Impaired Loans (Details) - Acquired Impaired Loans - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	$ 321,899	$ 476,980
Carrying Value	294,168	327,690
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	169,149	235,898
Carrying Value	154,108	166,712
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	123,542	207,660
Carrying Value	120,963	144,562
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	4,615	13,270
Carrying Value	4,203	5,946
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	23,467	18,333
Carrying Value	14,436	10,008
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	1,126	1,819
Carrying Value	$ 458	$ 462

Loan and Lease Receivables - _4

Loan and Lease Receivables - Summary of Changes in Accretable Yield for Acquired Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Receivables [Abstract]
Beginning balance	$ 41,306	$ 37,619	$ 36,446	$ 36,868
Additions			3,566
Accretion to interest income	(5,665)	(8,165)	(17,227)	(24,768)
Reclassification from nonaccretable difference, net	2,507	6,901	15,363	24,255
Ending balance	$ 38,148	$ 36,355	$ 38,148	$ 36,355

Loan and Lease Receivables - _5

Loan and Lease Receivables - Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-impaired Loans and Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	$ 3,455,802	$ 2,277,492	$ 2,216,499
Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	1,127,265	399,601
Loans and leases	1,095,455	376,419
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,272,204	891,693	861,885
Commercial Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	506,507	221,710
Loans and leases	498,329	211,359
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	705,196	577,218	582,662
Residential Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	141,011	32,605
Loans and leases	138,516	32,085
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	181,705	105,429	94,304
Construction, Land Development, and Other Land | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	39,694	1,926
Loans and leases	37,111	1,845
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,095,446	521,238	502,055
Commercial and Industrial | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	397,746	105,529
Loans and leases	384,260	94,731
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	12,194	4,228	3,252
Installment and Other | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	7,601	355
Loans and leases	4,007	42
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	189,057	177,686	$ 172,341
Lease Financing Receivables | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	34,706	37,476
Loans and leases	$ 33,232	$ 36,357

Allowance for Loan and Lease _3

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Allowance for loan and lease losses
Beginning balance	$ 19,687	$ 13,969	$ 16,706	$ 10,923
Provisions (releases)	5,842	3,900	14,913	9,306
Charge-offs	(2,421)	(2,299)	(9,228)	(5,322)
Recoveries	316	410	1,033	1,073
Ending balance	23,424	15,980	23,424	15,980
Ending balance:
Individually evaluated for impairment					$ 6,422		$ 2,949
Collectively evaluated for impairment					14,007		9,218
Allowance for loan and lease losses	23,424	13,969	23,424	15,980	23,424	$ 16,706	15,980
Loans and leases ending balance:
Individually evaluated for impairment					35,529		23,518
Collectively evaluated for impairment					3,126,105		1,850,381
Total loans and leases					3,455,802	2,277,492	2,216,499
Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2,995		3,813
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					294,168		342,600
Commercial Real Estate
Allowance for loan and lease losses
Beginning balance	6,453	3,668	4,794	1,945
Provisions (releases)	1,705	1,577	3,975	3,591
Charge-offs	(736)	(186)	(1,347)	(477)
Ending balance	7,422	5,059	7,422	5,059
Ending balance:
Individually evaluated for impairment					2,294		1,186
Collectively evaluated for impairment					3,413		1,844
Allowance for loan and lease losses	6,453	3,668	7,422	5,059	7,422	4,794	5,059
Loans and leases ending balance:
Individually evaluated for impairment					13,612		14,928
Collectively evaluated for impairment					1,104,484		673,851
Total loans and leases					1,272,204	891,693	861,885
Commercial Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					1,715		2,029
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					154,108		173,106
Residential Real Estate
Allowance for loan and lease losses
Beginning balance	1,648	1,835	1,638	2,483
Provisions (releases)	29	52	39	(400)
Charge-offs		(161)		(357)
Ending balance	1,677	1,726	1,677	1,726
Ending balance:
Individually evaluated for impairment					70		176
Collectively evaluated for impairment					1,150		1,237
Allowance for loan and lease losses	1,648	1,835	1,677	1,726	1,677	1,638	1,726
Loans and leases ending balance:
Individually evaluated for impairment					1,941		1,948
Collectively evaluated for impairment					582,292		428,565
Total loans and leases					705,196	577,218	582,662
Residential Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					457		313
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					120,963		152,149
Construction, Land Development, and Other Land
Allowance for loan and lease losses
Beginning balance	332	327	222	742
Provisions (releases)	58	(111)	586	(526)
Charge-offs			(418)
Ending balance	390	216	390	216
Ending balance:
Collectively evaluated for impairment					390		155
Allowance for loan and lease losses	332	327	390	216	390	222	216
Loans and leases ending balance:
Individually evaluated for impairment							565
Collectively evaluated for impairment					177,502		88,315
Total loans and leases					181,705	105,429	94,304
Construction, Land Development, and Other Land | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality							61
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					4,203		5,424
Commercial and Industrial
Allowance for loan and lease losses
Beginning balance	8,369	5,689	7,418	4,196
Provisions (releases)	3,579	1,440	8,959	3,932
Charge-offs	(858)	(763)	(5,539)	(1,762)
Recoveries	75		327
Ending balance	11,165	6,366	11,165	6,366
Ending balance:
Individually evaluated for impairment					4,044		1,585
Collectively evaluated for impairment					6,301		3,389
Allowance for loan and lease losses	8,369	5,689	11,165	6,366	11,165	7,418	6,366
Loans and leases ending balance:
Individually evaluated for impairment					19,962		6,075
Collectively evaluated for impairment					1,061,048		484,547
Total loans and leases					1,095,446	521,238	502,055
Commercial and Industrial | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					820		1,392
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					14,436		11,433
Installment and Other
Allowance for loan and lease losses
Beginning balance	30	344	41	334
Provisions (releases)	12	13	33	23
Charge-offs	(4)	(327)	(36)	(327)
Ending balance	38	30	38	30
Ending balance:
Individually evaluated for impairment					14		2
Collectively evaluated for impairment					21		10
Allowance for loan and lease losses	30	344	38	30	38	41	30
Loans and leases ending balance:
Individually evaluated for impairment					14		2
Collectively evaluated for impairment					11,722		2,762
Total loans and leases					12,194	4,228	3,252
Installment and Other | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					3		18
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					458		488
Lease Financing Receivables
Allowance for loan and lease losses
Beginning balance	2,855	2,106	2,593	1,223
Provisions (releases)	459	929	1,321	2,686
Charge-offs	(823)	(862)	(1,888)	(2,399)
Recoveries	241	410	706	1,073
Ending balance	2,732	2,583	2,732	2,583
Ending balance:
Collectively evaluated for impairment					2,732		2,583
Allowance for loan and lease losses	$ 2,855	$ 2,106	$ 2,732	$ 2,583	2,732	2,593	2,583
Loans and leases ending balance:
Collectively evaluated for impairment					189,057		172,341
Total loans and leases					$ 189,057	$ 177,686	$ 172,341

Allowance for Loan and Lease _4

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 3,700,000	$ 2,000,000	$ 6,700,000	$ 5,100,000
Commitments outstanding on troubled debt restructurings	500,000		500,000		$ 0
Recorded investment in troubled debt restructurings that subsequently defaulted within twelve months	0	0	340,000	0
Reserve for unfunded commitments	1,400,000		1,400,000		923,000
Provisions for (credits to) unfunded commitments	411,000	299,000	496,000	272,000
Charge-offs or recoveries related to reserve for unfunded commitments			0		$ 0
Acquired Impaired Loans
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 244,000	$ 559,000	$ (879,000)	$ 2,200,000

Allowance for Loan and Lease _5

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Recorded Investment, Unpaid Principal Balance, and Related Allowance for Loans and Leases Considered Impaired (Details) - Loans Excluding Acquired Impaired Loans - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Recorded Investment	$ 35,529	$ 31,111
Unpaid Principal Balance	39,136	34,479
Related Allowance	6,422	3,965
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	8,439	11,425
Recorded Investment, With an allowance recorded	5,173	2,459
Unpaid Principal Balance, With no related allowance recorded	9,566	12,936
Unpaid Principal Balance, With an allowance recorded	5,419	2,634
Related Allowance	2,294	1,101
Residential Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	1,689	2,075
Recorded Investment, With an allowance recorded	252	354
Unpaid Principal Balance, With no related allowance recorded	1,655	2,046
Unpaid Principal Balance, With an allowance recorded	253	351
Related Allowance	70	158
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	9,971	5,470
Recorded Investment, With an allowance recorded	9,991	9,314
Unpaid Principal Balance, With no related allowance recorded	11,694	6,774
Unpaid Principal Balance, With an allowance recorded	10,535	9,724
Related Allowance	4,044	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 _6

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Average Recorded Investment and Interest Income Recognized for Loans and Leases Considered Impaired (Details) - Loans Excluding Acquired Impaired Loans - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Financing Receivable Impaired [Line Items]
Average Recorded Investment	$ 33,782	$ 18,355
Interest Income Recognized	977	1,509
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	9,441	10,605
Average Recorded Investment, With an allowance recorded	5,022	1,043
Interest Income Recognized, With no related allowance recorded	232	419
Interest Income Recognized, With an allowance recorded	16	287
Residential Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	1,910	1,698
Average Recorded Investment, With an allowance recorded	330	444
Interest Income Recognized, With no related allowance recorded	24	33
Interest Income Recognized, With an allowance recorded	3	4
Construction, Land Development, and Other Land
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded		269
Average Recorded Investment, With an allowance recorded		19
Interest Income Recognized, With no related allowance recorded	15	2
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	8,018	2,391
Average Recorded Investment, With an allowance recorded	9,047	1,673
Interest Income Recognized, With no related allowance recorded	194	253
Interest Income Recognized, With an allowance recorded	484	500
Installment and Other
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With an allowance recorded	14	213
Interest Income Recognized, With an allowance recorded	$ 9	$ 11

Allowance for Loan and Lease _7

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 3,455,802	$ 2,277,492	$ 2,216,499
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,272,204	891,693	861,885
Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	705,196	577,218	582,662
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	181,705	105,429	94,304
Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,095,446	521,238	502,055
Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	12,194	4,228	3,252
Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	189,057	177,686	$ 172,341
Loans Excluding Acquired Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,161,634	1,949,802
Loans Excluding Acquired Impaired Loans | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,118,096	724,981
Loans Excluding Acquired Impaired Loans | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	584,233	432,656
Loans Excluding Acquired Impaired Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	177,502	99,483
Loans Excluding Acquired Impaired Loans | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,081,010	511,230
Loans Excluding Acquired Impaired Loans | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	11,736	3,766
Loans Excluding Acquired Impaired Loans | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	189,057	177,686
Loans Excluding Acquired Impaired Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,836,269	1,704,311
Loans Excluding Acquired Impaired Loans | Pass | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,017,225	638,066
Loans Excluding Acquired Impaired Loans | Pass | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	544,986	398,743
Loans Excluding Acquired Impaired Loans | Pass | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	159,712	73,935
Loans Excluding Acquired Impaired Loans | Pass | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	915,027	415,163
Loans Excluding Acquired Impaired Loans | Pass | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	11,696	3,732
Loans Excluding Acquired Impaired Loans | Pass | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	187,623	174,672
Loans Excluding Acquired Impaired Loans | Watch
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	245,057	176,996
Loans Excluding Acquired Impaired Loans | Watch | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	71,382	58,217
Loans Excluding Acquired Impaired Loans | Watch | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	30,287	29,165
Loans Excluding Acquired Impaired Loans | Watch | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,691	22,380
Loans Excluding Acquired Impaired Loans | Watch | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	128,597	67,024
Loans Excluding Acquired Impaired Loans | Watch | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases		20
Loans Excluding Acquired Impaired Loans | Watch | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	100	190
Loans Excluding Acquired Impaired Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	39,859	34,892
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,508	14,645
Loans Excluding Acquired Impaired Loans | Special Mention | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	5,729	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	3,099	3,168
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	15,654	13,535
Loans Excluding Acquired Impaired Loans | Special Mention | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	13
Loans Excluding Acquired Impaired Loans | Special Mention | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	856	1,293
Loans Excluding Acquired Impaired Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	40,288	33,331
Loans Excluding Acquired Impaired Loans | Substandard | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,981	14,053
Loans Excluding Acquired Impaired Loans | Substandard | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,231	2,497
Loans Excluding Acquired Impaired Loans | Substandard | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	21,732	15,508
Loans Excluding Acquired Impaired Loans | Substandard | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	27	14
Loans Excluding Acquired Impaired Loans | Substandard | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	317	1,259
Loans Excluding Acquired Impaired Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	161	272
Loans Excluding Acquired Impaired Loans | Doubtful | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 161	$ 272

Allowance for Loan and Lease _8

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Contractual Delinquency Information (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	$ 3,455,802	$ 2,277,492	$ 2,216,499
Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,272,204	891,693	861,885
Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	705,196	577,218	582,662
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	181,705	105,429	94,304
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,095,446	521,238	502,055
Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	12,194	4,228	3,252
Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	189,057	177,686	$ 172,341
Acquired Non-Impaired and Originated Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	44,429	30,950
Non-accrual	28,643	15,764
Current	3,117,205	1,918,852
Total loans and leases	3,161,634	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	11,031	12,613
Acquired Non-Impaired and Originated Loans | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	4,464	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	291
Acquired Non-Impaired and Originated Loans | Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	19,287	14,210
Non-accrual	12,553	8,459
Current	1,098,809	710,771
Total loans and leases	1,118,096	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	5,452	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	1,282	968
Acquired Non-Impaired and Originated Loans | Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,261	2,240
Non-accrual	1,631	2,092
Current	581,972	430,416
Total loans and leases	584,233	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	434	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	196
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Current	177,502	99,483
Total loans and leases	177,502	99,483
Acquired Non-Impaired and Originated Loans | Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	20,210	11,982
Non-accrual	13,958	4,348
Current	1,060,800	499,248
Total loans and leases	1,081,010	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	3,600	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	2,361	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	291
Acquired Non-Impaired and Originated Loans | Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	58	32
Non-accrual	23	14
Current	11,678	3,734
Total loans and leases	11,736	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	34	18
Acquired Non-Impaired and Originated Loans | Installment and Other | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,613	2,486
Non-accrual	478	851
Current	186,444	175,200
Total loans and leases	189,057	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	1,511	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	$ 624	$ 638

Allowance for Loan and Lease _9

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of TDR's by Loan Category (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018USD ($)Loan	Dec. 31, 2017USD ($)Loan
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	18	10
Pre-Modification Outstanding Recorded Investment	$ 10,501	$ 3,117
Post-Modification Outstanding Recorded Investment	8,589	2,630
Charge-offs	1,912	487
Specific Reserves	$ 1,795	$ 357
Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	6	4
Pre-Modification Outstanding Recorded Investment	$ 1,230	$ 1,061
Post-Modification Outstanding Recorded Investment	1,230	$ 1,061
Specific Reserves	$ 220
Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	12	6
Pre-Modification Outstanding Recorded Investment	$ 9,271	$ 2,056
Post-Modification Outstanding Recorded Investment	7,359	1,569
Charge-offs	1,912	487
Specific Reserves	$ 1,575	$ 357
Commercial Real Estate | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	3	3
Pre-Modification Outstanding Recorded Investment	$ 914	$ 912
Post-Modification Outstanding Recorded Investment	914	$ 912
Specific Reserves	$ 113
Commercial Real Estate | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	8	2
Pre-Modification Outstanding Recorded Investment	$ 2,678	$ 743
Post-Modification Outstanding Recorded Investment	2,637	743
Charge-offs	41
Specific Reserves	$ 420	$ 111
Commercial and Industrial | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	2
Pre-Modification Outstanding Recorded Investment	$ 193
Post-Modification Outstanding Recorded Investment	193
Specific Reserves	$ 107
Commercial and Industrial | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	4	3
Pre-Modification Outstanding Recorded Investment	$ 6,593	$ 1,246
Post-Modification Outstanding Recorded Investment	4,722	759
Charge-offs	1,871	487
Specific Reserves	$ 1,155	$ 246
Residential Real Estate | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	1	1
Pre-Modification Outstanding Recorded Investment	$ 123	$ 149
Post-Modification Outstanding Recorded Investment	$ 123	$ 149
Residential Real Estate | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan		1
Pre-Modification Outstanding Recorded Investment		$ 67
Post-Modification Outstanding Recorded Investment		$ 67

Allowance for Loan and Lease_10

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Loans Modified as Troubled Debt Restructurings (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Receivables [Abstract]
Beginning balance	$ 1,238	$ 981	$ 1,061	$ 602
Additions		673	37	1,017
Net payments	(8)	(23)	(56)	(59)
Net transfers from non-accrual			188	71
Ending balance	1,230	1,631	1,230	1,631
Beginning balance	5,776	470	1,570	552
Additions	1,667	194	7,123	194
Net payments	(84)	(8)	(1,002)	(19)
Charge-offs			(144)
Net transfers to accrual			(188)	(71)
Ending balance	7,359	656	7,359	656
Total troubled debt restructurings	$ 8,589	$ 2,287	$ 8,589	$ 2,287

Servicing Assets - Activity for

Servicing Assets - Activity for Servicing Assets and Related Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Transfers And Servicing [Abstract]
Beginning balance	$ 21,587	$ 21,424	$ 21,400	$ 21,091
Additions, net	1,489	1,727	5,680	4,675
Changes in fair value	(2,402)	(1,482)	(6,406)	(4,097)
Ending balance	$ 20,674	$ 21,669	$ 20,674	$ 21,669

Servicing Assets - Unpaid Princ

Servicing Assets - Unpaid Principal Balances of Loans Serviced for Others (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 1,222,288	$ 1,112,901
SBA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	1,135,871	1,021,143
USDA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 86,417	$ 91,758

Servicing Assets - Additional I

Servicing Assets - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Net Servicing Fees [Member]
Accounts Notes And Loans Receivable [Line Items]
Servicing fees, net of changes in fair value	$ 176,000	$ 959,000	$ 1,198,000	$ 2,954,000

Other Real Estate Owned - Chang

Other Real Estate Owned - Change in Other Real Estate Owned (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Banking And Thrift [Abstract]
Other real estate owned, beginning balance	$ 6,402	$ 12,684	$ 10,626	$ 16,570
Net additions to OREO	307	3,417	1,527	6,069
Dispositions of OREO	(1,519)	(1,989)	(6,750)	(8,045)
Valuation adjustments	(299)	(253)	(512)	(735)
Other real estate owned, ending balance	$ 4,891	$ 13,859	$ 4,891	$ 13,859

Other Real Estate Owned - Addit

Other Real Estate Owned - Additional Information (Details) - USD ($)	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 4,891,000	$ 6,402,000	$ 10,626,000	$ 13,859,000	$ 12,684,000	$ 16,570,000
Residential consumer mortgage loans in process of foreclosure	3,100,000		1,900,000
Residential Real Estate
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 657,000		$ 3,600,000

Goodwill, Core Deposit Intang_3

Goodwill, Core Deposit Intangible and Other Intangible Assets - Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance, Goodwill	$ 127,536	$ 51,975	$ 54,562	$ 51,975
Additions			72,974
Ending balance, Goodwill	127,536	51,975	127,536	51,975
Amortization	(1,898)	(769)	(3,795)	(2,307)
Core Deposits
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	33,917	18,247	16,720	19,776
Additions			19,060
Amortization	(1,822)	(764)	(3,685)	(2,293)
Ending balance	32,095	17,483	32,095	17,483
Accumulated amortization	$ 17,151	$ 12,703	$ 17,151	$ 12,703
Weighted average remaining amortization period	7 years 1 month 6 days	5 years 9 months 18 days	7 years 1 month 6 days	5 years 9 months 18 days
Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 3,194
Additions			$ 3,216
Amortization	(67)		(89)
Ending balance	3,127		3,127
Accumulated amortization	$ 89		$ 89
Weighted average remaining amortization period	11 years 8 months 12 days		11 years 8 months 12 days

Goodwill, Core Deposit Intang_4

Goodwill, Core Deposit Intangible and Other Intangible Assets - Additional Information (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Indefinite Lived Intangible Assets By Major Class [Line Items]
Other intangible assets, net	$ 35,248,000	$ 16,756,000
Trademark
Indefinite Lived Intangible Assets By Major Class [Line Items]
Other intangible assets, net	$ 26,000	$ 36,000

Goodwill, Core Deposit Intang_5

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	Sep. 30, 2018USD ($)
Goodwill And Intangible Assets Disclosure [Abstract]
2,018	$ 1,807
2,019	6,945
2,020	6,477
2,021	6,026
2,022	5,578
Thereafter	8,415
Total	$ 35,248

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($) $ in Thousands	Jul. 01, 2017	Jun. 30, 2017	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Income Tax [Line Items]
Effective tax rate						24.40%	24.40%
Corporate federal income tax rate			21.00%					35.00%
Net income tax benefit				$ 724,000
Deferred tax assets, net			$ 42,300			$ 42,300		$ 47,400
Illinois | State
Income Tax [Line Items]
Corporate income tax rate	7.00%	5.25%
State income tax benefit due to increased value of deferred tax asset related to net loss deduction					$ 4,600

Deposits - Schedule of Deposits

Deposits - Schedule of Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Non-interest bearing demand deposits	$ 1,175,222	$ 760,887
Interest bearing checking accounts	317,145	186,611
Money market demand accounts	661,271	349,862
Other savings	476,879	437,212
Time deposits (below $250,000)	916,014	627,255
Time deposits ($250,000 and above)	194,236	81,502
Total deposits	$ 3,740,767	$ 2,443,329

Deposits - Additional Informati

Deposits - Additional Information (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Deposits [Abstract]
Brokered deposits	$ 10,000,000	$ 0

Federal Home Loan Bank Advanc_3

Federal Home Loan Bank Advances - Summary of FHLB Advances (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank advances	$ 425,000	$ 361,506
Weighted average cost	2.30%	1.49%

Federal Home Loan Bank Advanc_4

Federal Home Loan Bank Advances - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank, total fixed-rate advances	$ 250,000,000
Federal home loan bank, total variable rate advances	$ 175,000,000
Federal home loan bank advances, Variable interest rate	2.22%
Federal home loan bank, required investment conversion ratio	0.045
Additional borrowing capacity from FHLB	$ 1,200,000,000	$ 795,000,000
Federal home loan bank advances maximum borrowing capacity as percentage of total assets	35.00%
2.36% Fixed-Rate Advances
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.36%
Federal home loan bank fixed rate advances, maturity date	2018-12
Minimum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank variable rate advances, maturity date	2018-10
Maximum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank variable rate advances, maturity date	2018-12

Other Borrowings - Summary of O

Other Borrowings - Summary of Other Borrowings (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Debt Disclosure [Abstract]
Securities sold under agreements to repurchase	$ 24,446	$ 31,187
Total	$ 24,446	$ 31,187

Other Borrowings - Additional I

Other Borrowings - Additional Information (Details) - USD ($)	Oct. 11, 2018	Jul. 31, 2017	Sep. 30, 2018	Sep. 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		$ 20,650,000
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
Ridgestone | Correspondent Bank | Amended Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, revolving credit conversion to non-revolving line of credit, description			In April 2017, the revolving line of credit was amended to a non-revolving line of credit as long as the outstanding balance exceeds $5.0 million.
Line of credit facility, revolving credit conversion to non-revolving line of credit, threshold amount						$ 5,000,000
Threshold amount for conversion of line of credit into revolving line of credit						5,000,000
Revolving line of credit facility, maximum borrowing capacity						$ 5,000,000
Line of credit facility, maturity date			Oct. 11, 2018
Ridgestone | Correspondent Bank | Amended Credit Agreement | LIBOR Rate
Line Of Credit Facility [Line Items]
Interest rate spread			2.50%
Ridgestone | Correspondent Bank | Amended Credit Agreement | Prime Rate
Line Of Credit Facility [Line Items]
Interest rate spread			0.25%
Ridgestone | Correspondent Bank | Third Amendment Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount			$ 0		$ 0
Ridgestone | Correspondent Bank | Third Amendment Revolving Credit Agreement | Subsequent Event
Line Of Credit Facility [Line Items]
Line of credit facility, amount	$ 10,000,000
Line of credit facility, extended maturity date	Oct. 10, 2019
Line of credit facility, interest rate terms	The amended revolving line of credit bears interest at either the LIBOR plus 225 basis points or the Prime Rate minus 50 basis points, based on the Company’s election, which is required to be communicated at least three business days prior to the commencement of an interest period. If the Company fails to provide timely notification, the interest rate will be Prime Rate minus 50 basis points. At September 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 | Third Amendment Revolving Credit Agreement | LIBOR Rate | Subsequent Event
Line Of Credit Facility [Line Items]
Interest rate spread	2.25%
Ridgestone | Correspondent Bank | Third Amendment Revolving Credit Agreement | Prime Rate | Subsequent Event
Line Of Credit Facility [Line Items]
Interest rate spread	0.50%

Other Borrowings - Summary of S

Other Borrowings - Summary of Short-term Credit Lines Available for Use (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Federal Reserve Bank of Chicago Discount Window Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 310,345	$ 144,248
Available Federal Funds Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 55,000	$ 55,000

Junior Subordinated Debenture_2

Junior Subordinated Debentures - Junior Subordinated Debentures by Issuance (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 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	36,615	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	$ (9,885)	$ (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%
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	4.11%
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 Debenture_3

Junior Subordinated Debentures - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Mar. 31, 2018
Debt Instrument [Line Items]
Principal amount	$ 46,500,000	$ 36,500,000
Accrued interest payable	2,971,000	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	$ 72,000	$ 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%
Accrued interest payable	$ 25,000	$ 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	4.11%
Accrued interest payable	$ 18,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread	1.78%

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Summary of Minimum Annual Rental Commitments for Operating Leases (Details) $ in Thousands	Sep. 30, 2018USD ($)
Commitments And Contingencies Disclosure [Abstract]
2,018	$ 944
2,019	3,316
2,020	2,777
2,021	2,450
2,022	1,488
Thereafter	3,167
Total	$ 14,142

Commitments and Contingent Li_4

Commitments and Contingent Liabilities - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Jun. 30, 2018	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Commitments And Contingencies Liabilities [Line Items]
Rental expenses		$ 1,400,000	$ 1,100,000	$ 4,200,000	$ 3,400,000
Sublease income		223,000	166,000	569,000	526,000
Minimum rental to be received in future on subleases		1,500,000		$ 1,500,000
Sublease contract maturity year				2,025
Data processing		$ 2,724,000	$ 2,399,000	$ 15,396,000	$ 7,255,000
Fixed rate loan commitments maturity year				2,048
Variable rate loan commitments maturity year				2,048
Maximum
Commitments And Contingencies Liabilities [Line Items]
Commitments to make loans period				90 days
Loan commitments fixed interest rate		20.00%		20.00%
Loan commitments variable interest rate		15.00%		15.00%
Minimum
Commitments And Contingencies Liabilities [Line Items]
Loan commitments fixed interest rate		2.00%		2.00%
Loan commitments variable interest rate		2.45%		2.45%
Contract termination
Commitments And Contingencies Liabilities [Line Items]
Data processing	$ 8,100,000

Commitments and Contingent Li_5

Commitments and Contingent Liabilities - Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	$ 76,047	$ 57,150
Variable Rate	968,682	470,766
Commitments to Extend Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	74,062	55,924
Variable Rate	944,577	467,429
Letters of Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	1,985	1,226
Variable Rate	$ 24,105	$ 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	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 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	$ 795,408		$ 583,236
Servicing assets, at fair value	20,674	$ 21,587	21,400	$ 21,669	$ 21,424	$ 21,091
Derivative assets	13,620		5,981
Derivative liabilities	2,769		994
U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	55,333		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	146,620		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	61,227		33,170
Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	37,413		29,976
Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	7,047		5,284
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	20,674		21,400
Derivative assets	13,620		5,981
Derivative liabilities	2,769		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	55,333		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	146,620		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	61,227		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	285,448		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	73,563		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	71,987		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	30,046		30,971
Fair Value, Measurements, Recurring | Small Business Administration mortgage-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	26,724
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	37,413		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	7,047		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	55,333		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	2,819		1,921
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	13,620		5,981
Derivative liabilities	2,769		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	146,620		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	60,538		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	285,448		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	73,563		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	71,987		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	30,046		30,971
Fair Value, Measurements, Recurring | Level 2 | Small Business Administration mortgage-backed Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Available-for-sale Securities, Fair Value	26,724
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	37,413		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	3,536		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	20,674		21,400
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	$ 692		$ 677

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) - USD ($)	Sep. 30, 2018	Sep. 30, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Fair value, assets, to or from level 3 transfers, amount	$ 0	$ 0
Fair value, liabilities, to or from level 3 transfers, amount	0	0
Fair value, equity, to or from level 3 transfers, amount	$ 0	$ 0

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Financial Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 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	4	3
Change in unrealized gain	11	6
Balance, end of period	1,381	1,089
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	5,680	4,675
Changes in fair value	(6,406)	(4,097)
Balance, end of period	$ 20,674	$ 21,669

Fair Value Measurement - Summ_3

Fair Value Measurement - Summary of Unobservable Inputs Used in Fair Value Measurements on Recurring Basis Categorized Within Level 3 of Fair Value Hierarchy (Details) - Fair Value, Measurements, Recurring - Level 3	9 Months Ended
	Sep. 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]
Expected weighted average loan life	9 months 18 days
Minimum | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.077
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected weighted average loan life	10 years 9 months 18 days
Maximum | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.244
Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected weighted average loan life	5 years 3 months 18 days
Weighted Average | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.149
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	us-gaap:MeasurementInputDefaultRateMember
Obligations of States, Municipalities, and Political Subdivisions | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.013
Obligations of States, Municipalities, and Political Subdivisions | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.024
Obligations of States, Municipalities, and Political Subdivisions | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.018
Single Issuer Trust Preferred
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Debt Instrument, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Instrument, Measurement Input [Extensible List]	us-gaap:MeasurementInputDefaultRateMember
Single Issuer Trust Preferred | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.049
Single Issuer Trust Preferred | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.070
Single Issuer Trust Preferred | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.061
Servicing Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Servicing Asset, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Servicing Assets | Minimum | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.021
Servicing Assets | Maximum | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.259
Servicing Assets | Weighted Average | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.109

Fair Value Measurement - Summ_4

Fair Value Measurement - Summary of Assets Measured at Fair Value on Non-recurring Basis, Excluding Acquired Impaired Loans (Details) - Non-recurring Basis - USD ($) $ in Thousands	Sep. 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	$ 11,318	$ 12,783
Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	1,871	2,271
Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	15,918	12,092
Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	4,891	10,626
Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	8,343	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	11,318	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	1,871	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	15,918	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	4,891	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	$ 8,343	$ 9,779

Fair Value Measurement - Summ_5

Fair Value Measurement - Summary of Estimated Fair Values of Financial Instruments and Levels Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Financial assets
Cash and due from banks	$ 25,162	$ 19,404
Interest bearing deposits with other banks	119,594	38,945
Securities held-to-maturity, fair value	99,933	117,277
Restricted stock, at cost	19,202	16,343
Loans held for sale	8,737	5,212
Loans and lease receivables, net	3,432,378	2,260,786
Accrued interest receivable	11,331	7,670
Financial liabilities
Federal Home Loan Bank advances	425,000	361,506
Securities sold under agreements to repurchase	24,446	31,187
Junior subordinated debentures issued to capital trusts, net	36,615	27,647
Level 1 | Carrying Amount
Financial assets
Cash and due from banks	25,162	19,404
Level 1 | Estimated Fair Value
Financial assets
Cash and due from banks	25,162	19,404
Level 2 | Carrying Amount
Financial assets
Interest bearing deposits with other banks	119,594	38,945
Securities held-to-maturity, fair value	102,683	117,163
Restricted stock, at cost	19,202	16,343
Financial liabilities
Non-interest bearing deposits	1,175,222	760,887
Interest bearing deposits	2,565,545	1,682,442
Accrued interest payable	2,971	1,306
Federal Home Loan Bank advances	425,000	361,506
Securities sold under agreements to repurchase	24,446	31,187
Level 2 | Estimated Fair Value
Financial assets
Interest bearing deposits with other banks	119,594	38,945
Securities held-to-maturity, fair value	99,933	117,277
Restricted stock, at cost	19,202	16,343
Financial liabilities
Non-interest bearing deposits	1,175,222	760,887
Interest bearing deposits	2,561,465	1,678,535
Accrued interest payable	2,971	1,306
Federal Home Loan Bank advances	425,000	361,500
Securities sold under agreements to repurchase	24,446	31,187
Level 3 | Carrying Amount
Financial assets
Loans held for sale	8,737	5,212
Loans and lease receivables, net	3,432,378	2,260,786
Accrued interest receivable	11,331	7,670
Financial liabilities
Junior subordinated debentures issued to capital trusts, net	36,615	27,647
Level 3 | Estimated Fair Value
Financial assets
Loans held for sale	9,707	5,851
Loans and lease receivables, net	3,356,116	2,240,235
Accrued interest receivable	11,331	7,670
Financial liabilities
Junior subordinated debentures issued to capital trusts, net	$ 42,693	$ 33,907

Derivative Instruments and He_3

Derivative Instruments and Hedge Activities - Summary of Derivative Financial Instruments and Classification on Consolidated Statements of Financial Condition (Details) - USD ($)	Sep. 30, 2018	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Notional Amount	$ 491,420,000	$ 344,726,000
Other Assets	13,620,000	5,981,000
Other Liabilities	2,769,000	994,000
Cash Flow Hedges
Derivatives Fair Value [Line Items]
Notional Amount	250,000,000
Other Assets	10,883,000
Other Interest Rate Swaps
Derivatives Fair Value [Line Items]
Notional Amount	236,916,000
Other Assets	2,737,000
Other Liabilities	2,766,000
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	10,883,000	5,030,000
Other Liabilities		38,000
Derivatives Not Designated As Hedging Instruments | Other Credit Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	4,504,000
Other Liabilities	3,000
Derivatives Not Designated As Hedging Instruments | Other Interest Rate Swaps
Derivatives Fair Value [Line Items]
Notional Amount	236,916,000	94,726,000
Other Assets	2,737,000	951,000
Other Liabilities	$ 2,766,000	$ 956,000

Derivative Instruments and He_4

Derivative Instruments and Hedge Activities - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Derivative notional amount	$ 491,420,000		$ 491,420,000		$ 344,726,000
Unrealized gain (loss) to be reclassified as an decrease to interest expense during the next twelve months	2,700,000		2,700,000
Credit valuation adjustment increase (decrease) to non-interest income	13,000	$ (6,000)	(25,000)	$ (36,000)
Full collateral posted	13,300,000		13,300,000
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	(428,000)	159,000	(863,000)	426,000
Other Interest Rate Swaps
Derivative [Line Items]
Derivative notional amount	236,916,000		$ 236,916,000
Derivative maturity date, start year			Dec. 31, 2018
Derivative maturity date, end year			Aug. 31, 2028
Derivative instruments transaction fees	230,000	$ 40,000	$ 1,200,000	$ 219,000
Other Credit Derivatives
Derivative [Line Items]
Derivative notional amount	4,500,000		4,500,000		0
Credit valuation adjustment increase (decrease) to non-interest income	34,000		57,000
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 He_5

Derivative Instruments and Hedge Activities - Summary of Cash Flow Hedges (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 491,420,000	$ 344,726,000
Derivative assets fair value	13,620,000	5,981,000
Derivative liabilities fair value	2,769,000	$ 994,000
Cash Flow Hedges
Derivative [Line Items]
Notional Amount	250,000,000
Derivative assets fair value	$ 10,883,000
Weighted average pay rates	1.67%
Weighted average receive rates	2.33%
Weighted average maturity	3 years 4 months 24 days

Derivative Instruments and He_6

Derivative Instruments and Hedge Activities - Summary of Net Gains (Losses) Recorded in Accumulated Other Comprehensive Income (Loss) and Consolidated Statements of Operations Relating to Cash Flow Derivative Instruments (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Unrealized holding gains (losses) arising during the period	$ 1,070	$ 17	$ 6,702	$ (1,408)
Interest Rate Swaps
Derivative [Line Items]
Unrealized holding gains (losses) arising during the period			6,702	(1,408)
Amount of Gain (Loss) Reclassified from OCI to Income as a Decrease to Interest Expense			$ 863	$ (426)

Derivative Instruments and He_7

Derivative Instruments and Hedge Activities - Summary of Other Interest Rate Swaps (Details) - USD ($)	9 Months Ended
	Sep. 30, 2018	Dec. 31, 2017
Derivative [Line Items]
Notional Amount	$ 491,420,000	$ 344,726,000
Derivative assets fair value	13,620,000	5,981,000
Derivative liabilities fair value	2,769,000	$ 994,000
Other Interest Rate Swaps
Derivative [Line Items]
Notional Amount	236,916,000
Derivative assets fair value	2,737,000
Derivative liabilities fair value	$ 2,766,000
Weighted average pay rates	4.64%
Weighted average receive rates	4.19%
Weighted average maturity	5 years 8 months 12 days

Derivative Instruments and He_8

Derivative Instruments and Hedge Activities - Summary of Company's Interest Rate Derivative and Offsetting Positions (Details) - USD ($) $ in Thousands	Sep. 30, 2018	Dec. 31, 2017
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Gross amounts recognized	$ 13,620	$ 5,981
Net amount presented in the Consolidated Statements of Financial Condition	13,620	5,981
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(757)	(232)
Collateral posted	(12,863)	(5,371)
Net credit exposure	0	378
Gross amounts recognized	2,769	994
Net amount presented in the Consolidated Statements of Financial Condition	2,769	994
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(757)	(232)
Collateral posted	(2,007)	(745)
Net credit exposure	$ 5	$ 17

Share-Based Compensation - Addi

Share-Based Compensation - Additional Information (Details) - USD ($)	Oct. 03, 2017	Jul. 06, 2017	Oct. 31, 2018	Oct. 31, 2014	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Jun. 30, 2017
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Common stock, voting par value					$ 0.01		$ 0.01
Proceeds from the exercise of stock options					$ 1,702,000
Income tax benefit					142,000	$ 348,000
Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Income tax benefit					$ 178,000	$ 38,000
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	58,900
Number of options exercised					146,513
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					$ 4,400,000
Omnibus Plan | Performance-based Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of restricted voting common stock granted					11,165
Period for number of shares earned under retun on average assets					3 years
Minimum target precentage in assets of peer group consisting publicly-traded bank holding companies					50.00%
Maximum target precentage in assets of peer group consisting publicly-traded bank holding companies					200.00%
Omnibus Plan | Performance-based Restricted Shares | 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 | Subsequent Event
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Shares of restricted voting common stock granted			5,000
Omnibus Plan | Common Stock | Restricted Shares | Subsequent Event | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period			3 years
Omnibus Plan | Common Stock | Restricted Shares | Subsequent Event | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period			4 years
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					123,748		0
Number of shares outstanding					1,654,272		1,783,020
Award contractual term					6 years 10 months 24 days		7 years 7 months 6 days
Options vested					307,163
Proceeds from the exercise of stock options					$ 1,500,000
Income tax benefit					$ 297,000
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 | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period				1 year
BYB Plan | Time Options Grants | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period				5 years
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 | Minimum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period				1 year
BYB Plan | Performance Options Grants | Maximum
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Award vesting period				5 years
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of options granted					680,787
Number of options exercised					22,765
Number of shares outstanding					658,022
Award contractual term					5 years 2 months 12 days
Proceeds from the exercise of stock options					$ 241,000
Income tax benefit					$ 64,000
Conversion calculation percentage					472.50%
FEB Plan | Restricted Shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares outstanding					0

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Changes in Restricted Shares (Details) - Omnibus Plan - Restricted Shares	9 Months Ended
	Sep. 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 - Su_2

Share-Based Compensation - Summary of Stock Compensation Expense (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation - restricted stock	$ 510	$ 857
Income tax benefit	142	348
Unrecognized compensation expense	$ 209	$ 1,132
Weighted-average amortization period remaining	1 year 2 months 12 days	1 year 2 months 12 days
Restricted Shares
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation - restricted stock	$ 638	$ 94
Income tax benefit	178	38
Unrecognized compensation expense	$ 3,379	$ 1,087
Weighted-average amortization period remaining	3 years 1 month 6 days	2 years 9 months 18 days

Share-Based Compensation - Fair

Share-Based Compensation - Fair Value Assumptions of Stock Options (Details) - BYB Plan - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 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 - Su_3

Share-Based Compensation - Summary Activity in shares Subjected to Options and Weighted Average Exercise Prices (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 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	(123,748)	0
Number of Shares, Forfeited	(5,000)
Number of Shares, Ending balance	1,654,272	1,783,020
Number of Shares, Exercisable	1,487,672
Weighted Average Exercise Price, Beginning balance	$ 11.91
Weighted Average Exercise Price, Exercised	11.79
Weighted Average Exercise Price, Forfeited	16.25
Weighted Average Exercise Price, Ending balance	11.91	$ 11.91
Weighted Average Exercise Price, Exercisable	$ 11.42
Intrinsic Value, Beginning balance	$ 19,718
Intrinsic Value, Exercised	1,345
Intrinsic Value, Ending balance	17,855	$ 19,718
Intrinsic Value, Exercisable	$ 16,780
Weighted Average Remaining Contractual Term (in Years)	6 years 10 months 24 days	7 years 7 months 6 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	6 years 9 months 18 days
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Granted	680,787
Number of Shares, Exercised	(22,765)
Number of Shares, Ending balance	658,022
Number of Shares, Exercisable	658,022
Weighted Average Exercise Price, Granted	$ 11.26
Weighted Average Exercise Price, Exercised	10.59
Weighted Average Exercise Price, Ending balance	11.28
Weighted Average Exercise Price, Exercisable	$ 11.28
Intrinsic Value, Granted	$ 7,544
Intrinsic Value, Exercised	281
Intrinsic Value, Ending balance	7,513
Intrinsic Value, Exercisable	$ 7,513
Weighted Average Remaining Contractual Term (in Years)	5 years 2 months 12 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	5 years 2 months 12 days

Earnings per Share - Additional

Earnings per Share - Additional Information (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share Basic [Line Items]
Shares outstanding	36,042,914	29,246,900	32,341,087	26,194,025
Stock Options
Earnings Per Share Basic [Line Items]
Shares outstanding			2,312,294	1,798,223
Restricted Stock Award
Earnings Per Share Basic [Line Items]
Shares outstanding			194,455	58,500

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		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Earnings Per Share [Abstract]
Net income	$ 14,536	$ 9,755	$ 24,072	$ 22,461
Dividends on preferred shares	196	195	587	11,081
Net income available to common stockholders	$ 14,340	$ 9,560	$ 23,485	$ 11,380
Weighted-average common stock outstanding:
Weighted-average common stock outstanding (basic)	36,042,914	29,246,900	32,341,087	26,194,025
Incremental shares	915,295	505,431	947,570	503,816
Weighted-average common stock outstanding (dilutive)	36,958,209	29,752,331	33,288,657	26,697,841
Basic earnings per common share	$ 0.40	$ 0.33	$ 0.73	$ 0.43
Diluted earnings per common share	$ 0.39	$ 0.32	$ 0.71	$ 0.43

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Preferred and Common Stock (Details) - $ / shares	Sep. 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	36,279,600	29,317,298
Common stock, voting shares outstanding	36,279,600	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 - Summar_2

Stockholders' Equity - Summary of Preferred and Common Stock (Parenthetical) (Details)	9 Months Ended	12 Months Ended
	Sep. 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		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2016
Class Of Stock [Line Items]
Dividends declared and paid			$ 587,000	$ 11,081,000
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	$ 196,000	$ 195,000	$ 587,000	$ 580,000

Consolidated Statements of Ch_4

Consolidated Statements of Change in Accumulated Other Comprehensive Income (Loss) - Schedule of Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 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	$ (2,027)	$ 1,864	(6,512)	2,720
Ending balance	629,861	459,533	629,861	459,533
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			4,213	(605)
Ending balance	7,813	1,628	7,813	1,628
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			(10,725)	3,325
Ending balance	(20,175)	(6,176)	(20,175)	(6,176)
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			(6,512)	2,720
Ending balance	$ (12,362)	$ (4,548)	$ (12,362)	$ (4,548)