Byline Bancorp (BY) 10-Q 8 Nov 19 2019 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2019	Nov. 07, 2019
Cover [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2019
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Trading Symbol	BY
Entity Registrant Name	Byline Bancorp, Inc.
Entity Central Index Key	0001702750
Current Fiscal Year End Date	--12-31
Entity Filer Category	Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	true
Entity Ex Transition Period	false
Entity Interactive Data Current	Yes
Document Quarterly Report	true
Document Transition Report	false
Entity Current Reporting Status	Yes
Entity Shell Company	false
Entity File Number	001-38139
Entity Tax Identification Number	36-3012593
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	180 North LaSalle Street, Suite 300
Entity Address, City or Town	Chicago
Entity Address, State or Province	IL
Entity Address, Postal Zip Code	60601
City Area Code	773
Local Phone Number	244-7000
Entity Common Stock, Shares Outstanding		38,174,780
Title of each class	Common Stock
Name of each exchange on which registered	NYSE

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 75,275	$ 30,190
Interest bearing deposits with other banks	33,564	91,670
Cash and cash equivalents	108,839	121,860
Equity and other securities, at fair value	7,648
Securities available-for-sale, at fair value	1,031,933	817,656
Securities held-to-maturity, at amortized cost (fair value at September 30, 2019—$4,502, December 31, 2018—$97,739)	4,417	99,266
Restricted stock, at cost	24,331	19,202
Loans held for sale	7,176	19,827
Loans and leases:
Loans and leases	3,831,090	3,501,626
Allowance for loan and lease losses	(31,585)	(25,201)
Net loans and leases	3,799,505	3,476,425
Servicing assets, at fair value	19,939	19,693
Accrued interest receivable	13,013	10,863
Premises and equipment, net	96,006	97,680
Assets held for sale	15,472	14,489
Other real estate owned, net	8,531	5,314
Goodwill	145,638	128,177
Other intangible assets, net	33,905	33,419
Bank-owned life insurance	9,699	5,961
Deferred tax assets, net	33,388	35,643
Due from counterparty	47,045	5,338
Other assets	31,793	31,761
Total assets	5,438,278	4,942,574
LIABILITIES
Non-interest-bearing demand deposits	1,221,431	1,192,873
Interest-bearing deposits:
NOW, savings accounts, and money market accounts	1,589,081	1,413,158
Time deposits	1,269,802	1,143,885
Total deposits	4,080,314	3,749,916
Accrued interest payable	4,778	3,484
Federal Home Loan Bank advances	506,000	425,000
Securities sold under agreements to repurchase	32,290	34,166
Junior subordinated debentures issued to capital trusts, net	37,207	36,768
Accrued expenses and other liabilities	41,823	42,568
Total liabilities	4,702,412	4,291,902
STOCKHOLDERS’ EQUITY
Preferred stock	10,438	10,438
Common stock, voting, $0.01 par value at September 30, 2019 and December 31, 2018; 150,000,000 shares authorized at September 30, 2019 and December 31, 2018; 38,169,126 shares issued and outstanding at September 30, 2019 and 36,343,239 issued and outstanding at December 31, 2018	378	361
Additional paid-in capital	579,564	546,849
Retained earnings	144,525	102,522
Accumulated other comprehensive income (loss), net of tax	961	(9,498)
Total stockholders’ equity	735,866	650,672
Total liabilities and stockholders’ equity	$ 5,438,278	$ 4,942,574

CONSOLIDATED STATEMENTS OF FI_2

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Securities held-to-maturity, fair value	$ 4,502	$ 97,739
Common stock, voting par value	$ 0.01	$ 0.01
Common stock, voting shares authorized	150,000,000	150,000,000
Common stock, voting shares issued	38,169,126	36,343,239
Common stock, voting shares outstanding	38,169,126	36,343,239

CONSOLIDATED STATEMENTS OF OPER

CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
INTEREST AND DIVIDEND INCOME
Interest and fees on loans and leases	$ 63,391	$ 55,045	$ 177,298	$ 128,326
Interest on taxable securities	6,554	5,076	18,550	13,703
Interest on tax-exempt securities	486	337	1,257	740
Other interest and dividend income	598	615	1,794	1,287
Total interest and dividend income	71,029	61,073	198,899	144,056
INTEREST EXPENSE
Deposits	9,618	5,971	27,000	12,214
Federal Home Loan Bank advances	2,771	1,723	7,044	4,441
Subordinated debentures and other borrowings	802	786	2,484	2,057
Total interest expense	13,191	8,480	36,528	18,712
Net interest income	57,838	52,593	162,371	125,344
PROVISION FOR LOAN AND LEASE LOSSES	5,931	5,842	16,321	14,913
Net interest income after provision for loan and lease losses	51,907	46,751	146,050	110,431
NON-INTEREST INCOME
ATM and interchange fees	973	1,540	2,635	3,303
Net gains on sales of securities available-for-sale	178		1,151	4
Change in fair value of equity securities, net	(15)		1,035
Net gains on sales of loans	9,405	5,015	23,110	22,214
Wealth management and trust income	653	674	1,874	866
Other non-interest income	918	1,672	2,582	4,058
Total non-interest income	14,806	10,902	40,977	36,236
NON-INTEREST EXPENSE
Salaries and employee benefits	24,537	21,312	71,081	58,834
Occupancy expense, net	3,745	3,548	12,362	11,802
Equipment expense	767	617	2,168	1,778
Loan and lease related expenses	1,949	1,015	5,367	3,886
Legal, audit and other professional fees	4,066	2,358	9,113	8,627
Data processing	4,062	2,724	11,055	15,396
Net loss (gain) recognized on other real estate owned and other related expenses	95	(284)	543	187
Regulatory assessments	228	675	540	1,282
Other intangible assets amortization expense	2,003	1,898	5,735	3,795
Advertising and promotions	843	537	2,284	1,133
Telecommunications	474	435	1,475	1,319
Other non-interest expense	2,679	2,880	8,358	6,769
Total non-interest expense	45,448	37,715	130,081	114,808
INCOME BEFORE PROVISION FOR INCOME TAXES	21,265	19,938	56,946	31,859
PROVISION FOR INCOME TAXES	5,923	5,402	15,796	7,787
NET INCOME	15,342	14,536	41,150	24,072
Dividends on preferred shares	196	196	587	587
INCOME AVAILABLE TO COMMON STOCKHOLDERS	$ 15,146	$ 14,340	$ 40,563	$ 23,485
EARNINGS PER COMMON SHARE
Basic	$ 0.40	$ 0.40	$ 1.09	$ 0.73
Diluted	$ 0.39	$ 0.39	$ 1.07	$ 0.71
Fees and Service Charges on Deposits [Member]
NON-INTEREST INCOME
Fees and charges	$ 1,612	$ 1,825	$ 4,823	$ 4,593
Loan Servicing Revenue [Member]
NON-INTEREST INCOME
Fees and charges	2,692	2,622	7,861	7,605
Loan Servicing Asset Revaluation [Member]
NON-INTEREST INCOME
Fees and charges	$ (1,610)	$ (2,446)	$ (4,094)	$ (6,407)

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (UNAUDITED) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Statement Of Other Comprehensive Income [Abstract]
Net income	$ 15,342	$ 14,536	$ 41,150	$ 24,072
Securities available-for-sale
Unrealized holding gains (losses) arising during the period	3,992	(3,451)	24,954	(14,859)
Reclassification adjustments for net gains included in net income	(178)		(1,151)	(4)
Tax effect	(1,062)	961	(6,762)	4,138
Net of tax	2,752	(2,490)	17,041	(10,725)
Cash flow hedges
Unrealized holding gains (losses) arising during the period	(251)	1,070	(5,484)	6,702
Reclassification adjustments for net gains included in net income	(363)	(428)	(1,643)	(863)
Tax effect	171	(179)	1,985	(1,626)
Net of tax	(443)	463	(5,142)	4,213
Total other comprehensive income (loss)	2,309	(2,027)	11,899	(6,512)
Comprehensive income	$ 17,651	$ 12,509	$ 53,049	$ 17,560

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS EQUITY - USD ($) $ in Thousands	Total	Preferred Stock	Common Stock	Additional Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2017	$ 458,578	$ 10,438	$ 292	$ 391,586	$ 61,349	$ (5,087)
Beginning balance, shares at Dec. 31, 2017		10,438	29,317,298
Net income	6,768				6,768
Other comprehensive income (loss), net of tax	(3,564)					(3,564)
Issuance of common stock upon exercise of stock options	1,005		$ 1	1,004
Issuance of common stock upon exercise of stock options, shares			86,750
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)					763	(763)
Cash dividends declared on preferred stock	(193)				(193)
Share-based compensation expense	342			342
Ending balance at Mar. 31, 2018	462,936	$ 10,438	$ 293	392,932	68,687	(9,414)
Ending balance, shares at Mar. 31, 2018		10,438	29,404,048
Beginning balance at Dec. 31, 2017	458,578	$ 10,438	$ 292	391,586	61,349	(5,087)
Beginning balance, shares at Dec. 31, 2017		10,438	29,317,298
Net income	24,072
Other comprehensive income (loss), net of tax	(6,512)
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)	(763)
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
Beginning balance at Dec. 31, 2017	458,578	$ 10,438	$ 292	391,586	61,349	(5,087)
Beginning balance, shares at Dec. 31, 2017		10,438	29,317,298
Ending balance at Dec. 31, 2018	650,672	$ 10,438	$ 361	546,849	102,522	(9,498)
Ending balance, shares at Dec. 31, 2018		10,438	36,343,239
Beginning balance at Mar. 31, 2018	462,936	$ 10,438	$ 293	392,932	68,687	(9,414)
Beginning balance, shares at Mar. 31, 2018		10,438	29,404,048
Net income	2,768				2,768
Other comprehensive income (loss), net of tax	(921)					(921)
Issuance of common stock upon exercise of stock options	130			130
Issuance of common stock upon exercise of stock options, shares			8,000
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)
Cash dividends declared on preferred stock	(198)				(198)
Share-based compensation expense	416			416
Ending balance at Jun. 30, 2018	616,406	$ 10,438	$ 360	544,686	71,257	(10,335)
Ending balance, shares at Jun. 30, 2018		10,438	36,218,955
Net income	14,536				14,536
Other comprehensive income (loss), net of tax	(2,027)					(2,027)
Issuance of common stock upon exercise of stock options	567		$ 1	566
Issuance of common stock upon exercise of stock options, shares			51,763
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
Cash dividends declared on preferred stock	(196)				(196)
Share-based compensation expense	403			403
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
Net income	17,121				17,121
Other comprehensive income (loss), net of tax	2,864					2,864
Issuance of common stock upon exercise of stock options	638			638
Issuance of common stock upon exercise of stock options, shares			58,639
Issuance of common stock in connection with restricted stock awards, shares			5,000
Issuance of common stock in connection with employee stock purchase plan	31			31
Cash dividends declared on preferred stock	(196)				(196)
Share-based compensation expense	353			353
Ending balance at Dec. 31, 2018	650,672	$ 10,438	$ 361	546,849	102,522	(9,498)
Ending balance, shares at Dec. 31, 2018		10,438	36,343,239
Net income	12,597				12,597
Other comprehensive income (loss), net of tax	4,519					4,519
Issuance of common stock upon exercise of stock options	636		$ 1	635
Issuance of common stock upon exercise of stock options, shares			50,662
Forfeiture of restricted stock awards, shares			(8,500)
Issuance of common stock in connection with employee stock purchase plan	291			291
Issuance of common stock in connection with employee stock purchase plan, shares			12,743
Cumulative-effect adjustment (ASU 2016-01) | ASU 2016-01					1,440	(1,440)
Cash dividends declared on preferred stock	(196)				(196)
Share-based compensation expense	230			230
Ending balance at Mar. 31, 2019	668,749	$ 10,438	$ 362	548,005	116,363	(6,419)
Ending balance, shares at Mar. 31, 2019		10,438	36,398,144
Beginning balance at Dec. 31, 2018	650,672	$ 10,438	$ 361	546,849	102,522	(9,498)
Beginning balance, shares at Dec. 31, 2018		10,438	36,343,239
Net income	41,150
Other comprehensive income (loss), net of tax	11,899
Cumulative-effect adjustment (ASU 2016-01)	(1,440)
Ending balance at Sep. 30, 2019	735,866	$ 10,438	$ 378	579,564	144,525	961
Ending balance, shares at Sep. 30, 2019		10,438	38,169,126
Beginning balance at Mar. 31, 2019	668,749	$ 10,438	$ 362	548,005	116,363	(6,419)
Beginning balance, shares at Mar. 31, 2019		10,438	36,398,144
Net income	13,211				13,211
Other comprehensive income (loss), net of tax	5,071					5,071
Issuance of common stock upon exercise of stock options	1,669		$ 1	1,668
Issuance of common stock upon exercise of stock options, shares			116,048
Issuance of common stock and stock options due to business combination, net of issuance costs	28,892		$ 15	28,877
Issuance of common stock and stock options due to business combination, net of issuance costs, shares			1,464,558
Issuance of common stock in connection with restricted stock awards, shares			141,207
Forfeiture of restricted stock awards, shares			(4,738)
Cash dividends declared on preferred stock	(195)				(195)
Share-based compensation expense	278			278
Ending balance at Jun. 30, 2019	717,675	$ 10,438	$ 378	578,828	129,379	(1,348)
Ending balance, shares at Jun. 30, 2019		10,438	38,115,219
Net income	15,342				15,342
Other comprehensive income (loss), net of tax	2,309					2,309
Issuance of common stock upon exercise of stock options	54			54
Issuance of common stock upon exercise of stock options, shares			3,472
Issuance cost in connection with business combination	(157)			(157)
Issuance of common stock in connection with restricted stock awards, shares			50,992
Forfeiture of restricted stock awards, shares			(14,642)
Issuance of common stock in connection with employee stock purchase plan	289			289
Issuance of common stock in connection with employee stock purchase plan, shares			14,085
Cash dividends declared on preferred stock	(196)				(196)
Share-based compensation expense	550			550
Ending balance at Sep. 30, 2019	$ 735,866	$ 10,438	$ 378	$ 579,564	$ 144,525	$ 961
Ending balance, shares at Sep. 30, 2019		10,438	38,169,126

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended					9 Months Ended		12 Months Ended
	Sep. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 15,342	$ 12,597	$ 17,121	$ 14,536	$ 6,768	$ 41,150	$ 24,072
Adjustments to reconcile net income to net cash from operating activities:
PROVISION FOR LOAN AND LEASE LOSSES	5,931			5,842		16,321	14,913
Impairment loss on assets held for sale						459	256
Depreciation and amortization of premises and equipment						4,701	4,089
Change in fair value of equity securities, net						(1,035)
Net amortization of securities						1,757	2,553
Net gains on sales of securities available-for-sale	(178)					(1,151)	(4)
Losses on disposal of premises and equipment							194
Net gains on sales of assets held for sale						(82)	(1,102)
Net gains on sales of loans	(9,405)			(5,015)		(23,110)	(22,214)
Originations of U.S. government guaranteed loans						(206,418)	(237,945)
Proceeds from U.S. government guaranteed loans sold						209,556	279,390
Accretion of premiums and discounts on acquired loans, net						(17,772)	(14,199)
Net change in servicing assets						(246)	726
Net valuation adjustments on other real estate owned	26			299		189	512
Net gains on sales of other real estate owned	(38)			(489)		(11)	(380)
Other intangible assets amortization expense	2,003			1,898		5,735	3,795
Amortization of time deposit premium						(145)	(273)
Amortization of Federal Home Loan Bank advances premium							(19)
Accretion of junior subordinated debentures discount						439	471
Share-based compensation expense						1,058	1,161
Deferred tax provision, net of valuation						2,364	9,656
Increase in cash surrender value of bank owned life insurance						(253)	(205)
Changes in assets and liabilities:
Accrued interest receivable						(2,920)	(593)
Other assets						(14,310)	(6,720)
Accrued interest payable						1,213	1,095
Accrued expenses and other liabilities						(5,955)	2,937
Net cash provided by operating activities						11,534	62,166
CASH FLOWS FROM INVESTING ACTIVITIES
Purchases of securities available-for-sale						(310,950)	(153,995)
Proceeds from maturities and calls of securities available-for-sale						76,297	13,630
Proceeds from paydowns of securities available-for-sale						69,455	45,785
Proceeds from sales of securities available-for-sale						92,103	544
Proceeds from paydowns of securities held-to-maturity							13,778
Purchases of Federal Home Loan Bank stock						(28,170)	(25,293)
Federal Home Loan Bank stock repurchases						23,455	23,794
Net change in loans and leases						(63,565)	(257,598)
Purchases of premises and equipment						(2,291)	(1,380)
Proceeds from sales of assets held for sale						1,373	4,414
Proceeds from sales of other real estate owned						2,539	6,686
Net cash received in acquisition of business						4,306	20,374
Net cash used in investing activities						(135,448)	(309,261)
CASH FLOWS FROM FINANCING ACTIVITIES
Net increase in deposits						40,372	275,443
Proceeds from Federal Home Loan Bank advances						6,358,600	4,460,000
Repayments of Federal Home Loan Bank advances						(6,282,900)	(4,396,487)
Proceeds from line of credit						5,680
Repayments of line of credit						(11,335)
Net decrease in securities sold under agreements to repurchase						(1,876)	(6,741)
Dividends paid on preferred stock						(587)	(587)
Proceeds from issuance of common stock upon exercise of stock options						2,359	1,702
Proceeds from issuance of common stock						580	172
Net cash provided by financing activities						110,893	333,502
NET (DECREASE) INCREASE IN CASH AND CASH EQUIVALENTS						(13,021)	86,407
CASH AND CASH EQUIVALENTS, beginning of period		$ 121,860	144,756		$ 58,349	121,860	58,349	$ 58,349
CASH AND CASH EQUIVALENTS, end of period	$ 108,839		$ 121,860	$ 144,756		108,839	144,756	$ 121,860
SUPPLEMENTAL DISCLOSURES OF CASH FLOW INFORMATION:
Cash paid during the period for interest						35,021	16,868
Cash payments during the period for taxes						16,090	3,114
SUPPLEMENTAL DISCLOSURES OF NON-CASH INVESTING AND FINANCING ACTIVITIES:
Change in fair value of available-for-sale securities, net of tax						17,041	(10,725)
Change in fair value of cash flow hedges, net of tax						(5,142)	4,213
Delayed payments of mortgage-backed securities						720	229
Transfer of securities from held-to-maturity to available-for-sale						94,837
Reclassification of equity and other securities						6,609
Transfers of loans to other real estate owned						3,916	1,527
Internally financed sale of other real estate owned						183	444
Transfers of land and premises to assets held for sale						2,733	2,531
Transfers of assets held for sale to premises and equipment							(415)
Transfers of premises and equipment to other assets							35
Transfer of other assets to assets held for sale							16
Due from counterparties						47,045	14,334
Due to broker							6,983
Total assets acquired from acquisition						341,375	1,142,766
Total liabilities assumed from acquisition						305,892	1,036,609
Common stock and stock options issued due to acquisition of business						$ 29,320	$ 152,127

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2019
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Basis of Presentation	These unaudited interim condensed consolidated financial statements include the accounts of Byline Illinois state chartered These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). In preparing these financial statements, the Company has evaluated events and transactions subsequent to September 30, 2019 for potential recognition or disclosure. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information in footnote disclosures normally included in financial statements prepared in accordance with GAAP has been condensed or omitted pursuant to the rules and regulations of the SEC and the accounting standards for interim financial statements. These financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Consolidated Financial Statements for the years ended December 31, 2018, 2017, and 2016. In accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 855, “Subsequent Events,” the Company’s management has evaluated subsequent events for potential recognition or disclosure through the date of the issuance of these consolidated financial statements. The Company has one reportable segment. The Company’s chief operating decision maker evaluates the operations of the Company using consolidated information for purposes of allocating resources and assessing performance. Therefore, segments disclosures are not required. No subsequent events were identified that would have required a change to the consolidated financial statements or disclosure in the notes to the consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity.

Accounting Pronouncements Recen

Accounting Pronouncements Recently Adopted or Issued	9 Months Ended
	Sep. 30, 2019
Accounting Changes And Error Corrections [Abstract]
Accounting Pronouncements Recently Adopted or Issued	Note 2—Accounting Pronouncements Recently Adopted or Issued The following reflect recent accounting pronouncements that have been adopted or are pending adoption by the Company. As the Company qualifies as an emerging growth company and has elected the extended transition period for complying with new or revised accounting pronouncements, it is not subject to new or revised accounting standards applicable to public companies during the extended transition period. The accounting pronouncements pending adoption below reflect effective dates for the Company as an emerging growth company with the extended transition period. Adopted Accounting Pronouncements Revenue from Contracts with Customers In May 2014, FASB issued Accounting Standards Update (“ASU”) No. 2014-09, deferred by ASU No. 2015-14 and clarifying standards, Revenue from Contracts with Customers , which creates Topics 606 and 610 and supersedes Topic 605, Revenue Recognition . The core principle of Topic 606 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In April 2016, FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing . The amendments in this ASU clarify the following two aspects of Topic 606: (1) identifying performance obligations and (2) licensing implementation guidance, while retaining the related principles for those areas. In May 2016, FASB issued ASU No. 2016-12, Narrow-Scope Improvements and Practical Expedients , amending ASC Topic 606, Revenue from Contracts with Customers . The amendments in this ASU affect only several narrow aspects of Topic 606. In November 2017, FASB issued ASU No. 2017-14, amending ASC Topic 606, Revenue from Contracts with Customers . The ASU amends the codification to incorporate additional previously issued guidance from the SEC. The SEC issued SAB 116 to bring existing SEC staff guidance into conformity with the FASB’s adoption of and amendments to ASC Topic 606. In general, the new guidance requires companies to use more judgment and make more estimates than under current guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The new authoritative guidance was initially effective for reporting periods after January 1, 2017 but was deferred to January 1, 2018. Given our emerging growth status, the Company adopted this new guidance on January 1, 2019 using the full retrospective method, meaning the standard is applied to all periods presented in the financial statements with the cumulative effect of initially applying the standard recognized at the beginning of the earliest period presented. The majority of the Company’s revenue streams, including interest and dividend income, servicing fees, and gains on sales of loans and investments, are outside the scope of Topic 606. Revenue streams reported as fees and service charges on deposits, ATM and interchange fees, and wealth management and trust income are within the scope of Topic 606. The Company applied the requirements of Topic 606 to the revenue streams that are within its scope. The adoption of Topic 606 did not result in any changes in the either timing or amount of recognized; there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition. However, the presentation of certain costs associated with our ATM and debit card income were offset against ATM and interchange income. This change in presentation resulted in $396,000 and $1.1 million of expenses for the three and nine months ended September 30, 2019, respectively, being netted against ATM and interchange fees and reported in non-interest income instead of as other non-interest expense in non-interest expense. In addition, to conform to the current period presentation, $241,000 and $837,000 of related expenses for the three and nine months ended September 30, 2018, respectively, were reclassified from other non-interest expense in non-interest expense to being netted against ATM and interchange fees in non-interest income. The Company elected to apply the practical expedient and therefore does not disclose information about remaining performance obligations that have an original expected term of one year or less and allows the Company to expense costs related to obtaining a contract as incurred when the amortization period would have been one year or less. The Company adopted ASU 2014-09 using the full retrospective approach. The following table presents the impact of adopting the new revenue standard on our Consolidated Statements of Operations for the periods presented (in thousands): For the Three Months Ended For the Three Months Ended September 30, 2019 September 30, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 973 $ 1,369 $ (396 ) $ 1,540 $ 1,781 $ (241 ) Non-interest expense: Other non-interest expense $ 2,679 $ 3,075 $ (396 ) $ 2,880 $ 3,121 $ (241 ) For the Nine Months Ended For the Nine Months Ended September 30, 2019 September 30, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 2,635 $ 3,757 $ (1,122 ) $ 3,303 $ 4,140 $ (837 ) Non-interest expense: Other non-interest expense $ 8,358 $ 9,480 $ (1,122 ) $ 6,769 $ 7,606 $ (837 ) Fees and service charges on deposits: Fees and service charges on deposits include transaction and non-transaction based deposit fees. Transaction based fees on deposit accounts are charged to deposit customers for specific services provided to the customer. These fees include such items as wire fees, official check fees, and overdraft fees. These are contracts specific to each individual transaction and do not extend beyond the individual transaction. The performance obligation is completed and the fees are recognized at the time the specific transactional service is provided to the customer. Non-transactional deposit fees are typically monthly account maintenance fees charged on deposit accounts. These are day-to-day contracts that can be cancelled by either party without notice. The performance obligation is satisfied and the fees are recognized on a monthly basis after the service period is completed. ATM and interchange fees: ATM fees represent fees earned when a foreign debit or ATM card is used in a Byline Bank ATM. These fees are assessed and paid at the time of each transaction as the performance obligation is satisfied, which is at the point in time that the transaction is performed and approved. Interchange fees represent fees earned when a debit card issued by the Bank is used to purchase goods or services at a merchant. The merchant's bank pays the Bank a default interchange rate set by MasterCard on a transaction by transaction basis. Interchange fees are assessed as the performance obligation is satisfied, which is at the point in time the card transaction is authorized. The performance obligation is satisfied and the fees are earned when the cost of the transaction is charged to the Bank cardholders’ card. Direct expenses associated with ATM and debit cards are recorded as a net reduction against the ATM and interchange income. Wealth management and trust income: Wealth management and trust income represents fees earned by the Bank for discretionary investment management, trust administration, fiduciary and/or custody services rendered. Fees vary and are based on a contract with the customer. Fee income is determined as a percentage of assets under management and is recognized over the period the underlying account is serviced. Although some trust appointments can last for generations, most contracts are generally cancellable at any time, with the customer subject to a pro-rated fee in the month of termination. Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments in this ASU require equity securities to be measured at fair value with changes in the fair value recognized through net income. The amendments allow equity investments that do not have readily determinable fair values to be remeasured at fair value under certain circumstances and require enhanced disclosures about those investments. The amendments simplify the impairment assessment of equity investments without readily determinable fair values. The amendments also eliminate the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. The amendments require entities to adjust fair value disclosures for financial instruments to be reflected at an exit price. The amendments in this ASU require separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This amendment excludes from net income gains or losses that the entity may not realize because those financial liabilities are not usually transferred or settled at their fair values before maturity. The amendments in this ASU require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or in the accompanying notes to the financial statements. The Company adopted the provisions of ASU No. 2016-01 as of January 1, 2019. The adoption of this ASU resulted in the Company reclassifying $1.4 million from other comprehensive income to retained earnings, representing the unrealized gain, net of tax, on available-for-sale for sale equity securities at the date of adoption. The provisions of ASU No. 2016-01 require any future changes in fair value of equity securities to be recorded in the Consolidated Statements of Operations which could result in additional volatility in non-interest income. At December 31, 2018, the Company held $6.6 million of available-for-sale equity investment securities, which were previously reported as available-for-sale securities, at fair value, and are now reported as equity and other securities, at fair value. In addition, the adoption of this ASU resulted in changing how the Company estimates the fair value of portfolio loans and leases for disclosure purposes. Fair values are estimated first by stratifying the portfolios of loans and leases with similar financial characteristics. Loans and leases are segregated by type such as commercial real estate, residential mortgage, construction, land, and development, commercial and industrial, consumer and other. Each loan and lease category is further segmented into fixed- and adjustable-rate interest terms. An estimate of fair value is then calculated based on discounted cash flows using as a discount rate based on the current rate offered on similar products, plus an adjustment for liquidity to reflect the non-homogeneous nature of the loans and leases, as well as a quarterly loss rate based on historical losses to arrive at an estimated exit price fair value. Fair value for impaired loans and leases is also based on recent appraisals or estimated cash flows discounted using rates commensurate with risk associated with the estimated cash flows. Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information. Derivatives and Hedging (Topic 815) In August 2017, FASB issued ASU No. 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this ASU better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The Company adopted the provisions of ASU No. 2017-12 on January 1, 2019. Upon adoption, the Company elected to reclassify $94.8 million of securities held-to-maturity to securities available-for-sale, which did not impact on the Consolidated Statements of Operations Compensation—Stock Compensation (Topic 718) In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting . The amendments in the ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all of the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification. (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified. (3) the classification of the modified award is an equity instrument or liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period, for reporting periods for which financial statements have not yet been issued. The amendments should be applied prospectively to an award modified on or after the adoption date. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-09 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Statement of Cash Flows (Topic 230) In August 2016, FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments . There is diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230 and other Topics. This ASU addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. Those eight issues are (1) debt prepayment or debt extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transactions, and (8) separately identifiable cash flows and application of the predominance principle. Current GAAP either is unclear or does not include specific guidance on these eight cash flow classification issues. These amendments provide guidance for each of the eight issues, thereby reducing current and potential future diversity in practice. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. Given the Company’s emerging growth company status, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company adopted the provisions of ASU No. 2016-15 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash Business Combinations (Topic 805) In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business . The guidance clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. This guidance is effective for annual and interim periods beginning after December 15, 2017. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-01 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. 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: for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The amendments add the following disclosure requirements: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Early adoption is permitted. The Company early adopted these amendments in 2018, which did not have a material impact on the Company’s Consolidated Financial Statements. Issued Accounting Pronouncements Pending Adoption Leases (Topic 842) In February 2016, FASB issued ASU No. 2016-02, Leases . The amendments in this ASU require lessees to recognize the following for all leases (with the exception of short-term) at the commencement date: a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The amendments in this ASU leave lessor accounting largely unchanged, although certain targeted improvements were made to align lessor accounting with the lessee accounting model. This ASU simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. 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. In October 2019, FASB voted to defer the effective date of this ASU for entities not classified as Public Business Entities (PBEs). Our status as an emerging growth company makes us eligible for this deferral. Assuming the Company remains an emerging growth company, the proposed guidance will be effective for reporting periods after December 15, 2020, and interim periods with fiscal years beginning after December 15, 2021. The Company expects an increase in assets and liabilities as a result of recognizing additional right-of-use assets and liabilities under lease contracts in which the Company is lessee. While the Company has not quantified the impact of this ASU on its direct financing lease portfolio, it does not expect a material change in its accounting for the initial direct costs related to these leases. Financial Instruments—Credit Losses (Topic 326) In June 2016, FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments . Current GAAP requires an “incurred loss” methodology for recognizing credit losses that delays recognition until it is probable a loss has been incurred. The main objective of this ASU is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The amendments in this ASU replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendments in this ASU require a financial asset (or group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. The measurement of expected credit losses will be based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendments in this ASU broaden the information that an entity must consider in developing its expected credit loss estimate for assets measured either collectively or individually. The use of forecasted information incorporates more timely information in the estimate of expected credit loss, which will be more useful to users of the financial statements. In October 2019, FASB voted to defer the effective date of the ASU for entities not classified as PBEs. Once issued, the Company intends to exercise the extension applicable to emerging growth companies. The Company is in process of implementation and determining the impact that this ASU 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.

Acquisitions

Acquisitions	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Acquisitions	Note 3—Acquisitions On April 30, 2019, the Company acquired all of the outstanding common stock of Oak Park River Forest Bankshares, Inc. (“Oak Park River Forest”) and its subsidiary pursuant to an Agreement and Plan of Merger, dated as of October 17, 2018 (the “OPRF Merger Agreement”). Oak Park River Forest operated one wholly owned subsidiary, Community Bank of Oak Park River Forest. Oak Park River Forest was merged with and into Byline. As a result of the merger, Oak Park River Forest’s subsidiary bank, Community Bank of Oak Park River Forest, was merged with and into Byline Bank, with Byline Bank as the surviving bank. At the effective time of the merger (the “OPRF Effective Time”), each share of Oak Park River Forest’s common stock was converted into the right to receive: (1) 7.9321 shares of Byline’s common stock, and (2) an amount in cash equal to $6.2 million divided by the number of outstanding shares of Oak Park River Forest common stock as of the closing date, with cash paid in lieu of any fractional shares. The per share cash consideration was based on the total $6.2 million divided by the outstanding shares of Oak Park River Forest common stock, or $33.375 per outstanding share. Based on the closing price of the Company’s common stock of $20.02, as reported by the New York Stock Exchange, and 1,464,558 shares of common stock issued with respect to the outstanding shares of Oak Park River Forest common stock, the stock consideration was valued at $29.3 million. Options to acquire 35,870 shares of Oak Park River Forest common stock that were outstanding at the OPRF Effective Time were cancelled, at the option holders election, in exchange for a cash payment in accordance with the OPRF Merger agreement of $4.2 million, to be paid after the closing date. The value of the total merger consideration at closing was $35.5 million before issuance costs of $429,000. The transaction resulted in goodwill of $17.5 million, which is nondeductible for tax purposes, as this acquisition was a nontaxable transaction. Goodwill represents the premium paid over the fair value of the net tangible and intangible assets acquired and reflects related synergies expected from the combined operations. The Company incurred Oak Park River Forest merger-related expenses, including acquisition advisory expenses, of $2.3 million for the nine months ended September 30, 2019. The Company incurred merger-related income of $135,000 for the three months ended September 30, 2019, resulting from a legal fee credit. Core system conversion expenses were $1.2 million $1.9 million related to the Oak Park River Forest acquisition for the three and nine months ended September 30, 2019, respectively. These expenses are reflected in non-interest expense on the Consolidated Statements of Operations. The acquisition of Oak Park River Forest 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. 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. 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 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 issuance costs of $852,000. The transaction resulted in goodwill of $73.6 million, which is nondeductible for tax purposes, as this acquisition was a nontaxable transaction. The Company incurred First Evanston merger-related expenses, including acquisition advisory expenses, The acquisition of First Evanston was accounted for using the acquisition method of accounting in accordance with ASC Topic 805. Assets acquired, liabilities assumed and consideration exchanged were recorded at their respective acquisition date fair values. Determining the fair value of assets and liabilities involves significant judgment regarding methods and assumptions used to calculate estimated fair values. The fair value adjustments associated with the First Evanston transaction were finalized during the fourth quarter of 2018. The following table presents a summary of the fair values of assets acquired and liabilities assumed as of the acquisition dates: Preliminary Estimates April 30, 2019 Oak Park River Forest May 31, 2018 First Evanston Assets Cash and cash equivalents $ 10,469 $ 47,378 Securities available-for-sale 30,343 128,063 Restricted stock 414 1,360 Loans 261,151 916,011 Premises and equipment 3,488 15,890 Other real estate owned 2,201 — Other intangible assets 6,220 22,276 Bank-owned life insurance 3,485 — Deferred tax assets, net 4,887 2,302 Other assets 1,256 8,845 Total assets acquired 323,914 1,142,125 Liabilities Deposits 290,171 1,022,268 Line of credit 5,655 — Federal Home Loan Bank advances 5,300 — Junior subordinated debentures — 8,497 Accrued expenses and other liabilities 4,766 5,844 Total liabilities assumed 305,892 1,036,609 Net assets acquired $ 18,022 $ 105,516 Consideration paid Common stock (2019 - 1,464,558 shares issued at $20.02 per share, 2018 - 6,682,850 shares issued at $21.62 per share) 29,320 144,483 Outstanding stock options converted to Byline stock options — 7,644 Cash paid 6,163 27,004 Total consideration paid 35,483 179,131 Goodwill $ 17,461 $ 73,615 The following table presents the acquired non-impaired loans as of the acquisition dates: April 30, 2019 Oak Park River Forest May 31, 2018 First Evanston Fair value $ 212,587 $ 890,986 Gross contractual amounts receivable 275,553 1,057,374 Estimate of contractual cash flows not expected to be collected (1) 23,932 36,544 Estimate of contractual cash flows expected to be collected 251,621 1,020,830 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default. The discount on the acquired non-impaired loans is being accreted into income over the life of the loans on an effective yield basis. The following table provides the unaudited pro forma information for the results of operations for the three and nine months ended September 30, 2019 and 2018, as if the acquisitions had occurred on January 1, 2018. The pro forma results combine the historical results of First Evanston and Oak Park River Forest into the Company’s Consolidated Statements of Operations, including the impact of certain acquisition accounting adjustments, which includes loan discount accretion, intangible assets amortization, deposit premium accretion, and borrowing, net of discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2018. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The acquisition-related expenses that have been recognized are included in net income in the following table for the three and nine months ended September 30, 2019 and 2018. For the Three Months Ended For the Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Total revenues (net interest income and non-interest income) $ 72,644 $ 69,019 $ 209,765 $ 200,371 Net income $ 15,342 $ 15,673 $ 45,138 $ 42,160 Earnings per share—basic $ 0.40 $ 0.41 $ 1.18 $ 1.11 Earnings per share—diluted $ 0.39 $ 0.40 $ 1.16 $ 1.08 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, 2019, and Oak Park River Forest for the period beginning May 1, 2019 through September 30, 2019. Revenues and earnings of the acquired companies since the acquisition date have not been disclosed as it is not practicable as First Evanston and Oak Park River Forest were both merged into the Company and separate financial information is not readily available.

Securities

Securities	9 Months Ended
	Sep. 30, 2019
Investments Debt And Equity Securities [Abstract]
Securities	Note 4—Securities The following September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 42,381 $ 461 $ — $ 42,842 U.S. Government agencies 177,082 1,048 (272 ) 177,858 Obligations of states, municipalities, and political subdivisions 96,564 2,269 (231 ) 98,602 Residential mortgage-backed securities Agency 329,145 2,178 (2,313 ) 329,010 Non-agency 119,661 644 (245 ) 120,060 Commercial mortgage-backed securities Agency 150,891 1,698 (556 ) 152,033 Non-agency 31,224 276 — 31,500 Corporate securities 46,821 415 (42 ) 47,194 Other securities 32,955 — (121 ) 32,834 Total $ 1,026,724 $ 8,989 $ (3,780 ) $ 1,031,933 September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 4,417 $ 85 $ — $ 4,502 Total $ 4,417 $ 85 $ — $ 4,502 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 52,775 $ 81 $ (189 ) $ 52,667 U.S. Government agencies 187,427 367 (1,296 ) 186,498 Obligations of states, municipalities, and political subdivisions 60,686 133 (586 ) 60,233 Residential mortgage-backed securities Agency 284,038 101 (11,176 ) 272,963 Non-agency 84,998 199 (1,576 ) 83,621 Commercial mortgage-backed securities Agency 93,543 55 (3,164 ) 90,434 Non-agency 31,458 — (1,000 ) 30,458 Corporate securities 34,716 67 (610 ) 34,173 Other securities 4,613 2,127 (131 ) 6,609 Total $ 834,254 $ 3,130 $ (19,728 ) $ 817,656 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,835 $ 40 $ (210 ) $ 23,665 Residential mortgage-backed securities Agency 40,082 93 (531 ) 39,644 Non-agency 35,349 — (919 ) 34,430 Total $ 99,266 $ 133 $ (1,660 ) $ 97,739 The Company did not classify securities as trading during the three or nine months ended September 30, 2019 or during 2018. The Company adopted the provisions of ASU No. 2016-01 as of January 1, 2019. The adoption of this ASU resulted in the reclassification of available-for-sale equity securities, at fair value to a separate line item on the Company’s Consolidated Statements of Financial Condition, and the reclassification of $1.4 million from other comprehensive income to retained earnings, representing the net unrealized gain, net of tax, on available-for-sale for sale equity securities at the date of adoption. At December 31, 2018, the Company held $6.6 million of available-for-sale equity investment securities which were reported as available-for-sale securities, at fair value, and are now reported as equity and other securities, at fair value. Additionally, the Company adopted the provisions of ASU No. 2017-12 on January 1, 2019, and elected to reclassify $94.8 million of securities held-to-maturity to securities available-for-sale, which did not have an impact on the Consolidated Statements of Operations. Gross unrealized losses and fair values, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2019 and December 31, 2018, are summarized as follows: Less than 12 Months 12 Months or Longer Total September 30, 2019 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Government agencies 5 $ 14,834 $ (163 ) $ 20,266 $ (109 ) $ 35,100 $ (272 ) Obligations of states, municipalities and political subdivisions 4 9,960 (226 ) 1,417 (5 ) 11,377 (231 ) Residential mortgage-backed securities Agency 40 32,436 (179 ) 204,649 (2,134 ) 237,085 (2,313 ) Non-agency 11 36,826 (62 ) 28,142 (183 ) 64,968 (245 ) Commercial mortgage-backed securities Agency 8 38,571 (256 ) 33,769 (300 ) 72,340 (556 ) Corporate securities 5 9,276 (42 ) — — 9,276 (42 ) Other securities 1 32,834 (121 ) — — 32,834 (121 ) Total 74 $ 174,737 $ (1,049 ) $ 288,243 $ (2,731 ) $ 462,980 $ (3,780 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 18 $ 23,835 $ (52 ) $ 9,865 $ (137 ) $ 33,700 $ (189 ) U.S. Government agencies 25 43,487 (80 ) 50,101 (1,216 ) 93,588 (1,296 ) Obligations of states, municipalities and political subdivisions 56 13,926 (97 ) 18,563 (489 ) 32,489 (586 ) Residential mortgage-backed securities Agency 42 4,288 (45 ) 254,121 (11,131 ) 258,409 (11,176 ) Non-agency 8 59,107 (1,378 ) 4,009 (198 ) 63,116 (1,576 ) Commercial mortgage-backed securities Agency 9 21,356 (447 ) 52,640 (2,717 ) 73,996 (3,164 ) Non-agency 5 — — 30,458 (1,000 ) 30,458 (1,000 ) Corporate securities 15 25,762 (342 ) 4,642 (268 ) 30,404 (610 ) Other securities 1 — — 2,844 (131 ) 2,844 (131 ) Total 179 $ 191,761 $ (2,441 ) $ 427,243 $ (17,287 ) $ 619,004 $ (19,728 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 23 $ 8,127 $ (58 ) $ 8,792 $ (152 ) $ 16,919 $ (210 ) Residential mortgage-backed securities Agency 16 6,625 (150 ) 21,139 (381 ) 27,764 (531 ) Non-agency 7 21,499 (503 ) 12,931 (416 ) 34,430 (919 ) Total 46 $ 36,251 $ (711 ) $ 42,862 $ (949 ) $ 79,113 $ (1,660 ) Certain T o available-for-sale The proceeds from all sales of securities three and nine months ended September 30, 2019 For the Three Months Ended For the Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Proceeds $ 32,509 $ — $ 92,103 $ 544 Gross gains 225 — 1,274 4 Gross losses 47 — 123 — There were $178,000 in net gains reclassified from income income income Securities pledged at September 30, 2019 and December 31, 2018 had carrying amounts of $306.9 million and $244.7 million, At September 30, 2019, the Amortized Cost Fair Value Equity and other securities, at fair value Due after ten years $ 697 $ 697 No defined maturity 6,951 6,951 Total $ 7,648 $ 7,648 Available-for-sale Due in one year or less $ 59,697 $ 59,875 Due from one to five years 123,941 125,158 Due from five to ten years 136,438 137,993 Due after ten years 75,727 76,304 Mortgage-backed securities 630,921 632,603 Total $ 1,026,724 $ 1,031,933 Held-to-maturity Due from one to five years $ 3,805 $ 3,873 Due from five to ten years 612 629 Total $ 4,417 $ 4,502

Loan and Lease Receivables

Loan and Lease Receivables	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 Commercial real estate $ 1,305,438 $ 1,261,594 Residential real estate 748,875 704,899 Construction, land development, and other land 281,868 186,258 Commercial and industrial 1,300,997 1,145,240 Installment and other 9,284 13,675 Lease financing receivables 180,273 187,797 Total loans and leases 3,826,735 3,499,463 Net unamortized deferred fees and costs 1,444 (1,293 ) Initial direct costs 2,911 3,456 Allowance for loan and lease losses (31,585 ) (25,201 ) Net loans and leases $ 3,799,505 $ 3,476,425 September 30, December 31, 2019 2018 Lease financing receivables Net minimum lease payments $ 196,163 $ 204,646 Unguaranteed residual values 1,379 1,535 Unearned income (17,269 ) (18,384 ) Total lease financing receivables 180,273 187,797 Initial direct costs 2,911 3,456 Lease financial receivables before allowance for lease losses $ 183,184 $ 191,253 Total loans and leases consist of originated loans and leases, acquired impaired loans and acquired non-impaired loans and leases. At September 30, 2019 and December 31, 2018, total loans and leases included the guaranteed amount of U.S. government guaranteed loans of $139.8 million and $108.7 million, respectively. At September 30, 2019 and December 31, 2018, installment and other loans included overdraft deposits of $2.0 million and $1.7 million, respectively, which were reclassified as loans. At September 30, 2019 and December 31, 2018, loans and loans held for sale pledged as security for borrowings were $1.9 billion and $1.4 billion. The minimum Minimum Lease Payments 2019 $ 18,025 2020 70,292 2021 51,235 2022 33,733 2023 17,614 Thereafter 5,264 Total $ 196,163 Originated Topic more than insignificant having evidence of credit quality deterioration do not qualify to be accounted for as acquired impaired loans and Topic September 30, 2019 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 772,559 $ 142,435 $ 391,294 $ 1,306,288 Residential real estate 497,839 109,409 141,855 749,103 Construction, land development, and other land 236,780 4,562 39,657 280,999 Commercial and industrial 1,096,400 18,349 187,413 1,302,162 Installment and other 7,818 267 1,269 9,354 Lease financing receivables 160,061 — 23,123 183,184 Total loans and leases $ 2,771,457 $ 275,022 $ 784,611 $ 3,831,090 December 31, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 652,234 $ 146,808 $ 462,565 $ 1,261,607 Residential real estate 466,309 113,934 124,659 704,902 Construction, land development, and other land 144,128 3,779 37,442 185,349 Commercial and industrial 803,508 12,617 328,672 1,144,797 Installment and other 11,718 404 1,596 13,718 Lease financing receivables 159,901 — 31,352 191,253 Total loans and leases $ 2,237,798 $ 277,542 $ 986,286 $ 3,501,626 Acquired impaired loans —As part of the First Evanston acquisition, the Bank acquired impaired loans that are accounted for under ASC 310-30 in the amount of $25.0 million. As part of the Oak Park River Forest acquisition, the Bank acquired impaired loans in the amount of $48.6 million. Refer to Note 3—Acquisitions for additional information regarding the transaction. 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 (First Evanston) and April 30, 2019 (Oak Park River Forest): First Evanston Oak Park River Forest Undiscounted contractual cash flows $ 33,594 $ 65,223 Undiscounted cash flows not expected to be collected (non-accretable difference) (5,003 ) (8,158 ) Undiscounted cash flows expected to be collected 28,591 57,065 Accretable yield at acquisition (3,566 ) (8,501 ) Estimated fair value of impaired loans acquired at acquisition $ 25,025 $ 48,564 The outstanding September 30, 2019 December 31, 2018 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 196,495 $ 142,435 $ 216,137 $ 146,808 Residential real estate 161,742 109,409 173,962 113,934 Construction, land development, and other land 13,276 4,562 11,962 3,779 Commercial and industrial 27,320 18,349 24,972 12,617 Installment and other 1,121 267 1,735 404 Total acquired impaired loans $ 399,954 $ 275,022 $ 428,768 $ 277,542 The following table summarizes the changes in accretable yield for acquired impaired loans for the three and nine months ended September 30, 2019 and 2018: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Beginning balance $ 46,538 $ 41,306 $ 37,115 $ 36,446 Additions — — 8,501 3,566 Accretion to interest income (7,703 ) (5,665 ) (17,772 ) (17,227 ) Reclassification from nonaccretable difference, net 5,153 2,507 16,144 15,363 Ending balance $ 43,988 $ 38,148 $ 43,988 $ 38,148 Acquired non-impaired loans and leases —The Company acquired non-impaired loans as part of the First Evanston acquisition in the amount of $891.0 million. The Company acquired non-impaired loans as part of the Oak Park River Forest acquisition in the amount of $212.6 million. Refer to Note 3—Acquisitions for additional information regarding the transaction. The unpaid September 30, 2019 December 31, 2018 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 400,422 $ 391,294 $ 473,262 $ 462,565 Residential real estate 144,075 141,855 127,478 124,659 Construction, land development, and other land 40,778 39,657 38,494 37,442 Commercial and industrial 194,756 187,413 344,879 328,672 Installment and other 1,303 1,269 1,831 1,596 Lease financing receivables 24,754 23,123 32,977 31,352 Total acquired non-impaired loans and leases $ 806,088 $ 784,611 $ 1,018,921 $ 986,286

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	9 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments	Note 6—Allowance for Loans and leases The following September 30, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Allowance for loan and lease losses Three months ended Beginning balance $ 8,934 $ 2,171 $ 691 $ 17,126 $ 67 $ 2,143 $ 31,132 Provisions 1,075 74 125 4,198 (12 ) 471 5,931 Charge-offs (1,459 ) — — (3,561 ) (1 ) (665 ) (5,686 ) Recoveries 3 6 — 20 1 178 208 Ending balance $ 8,553 $ 2,251 $ 816 $ 17,783 $ 55 $ 2,127 $ 31,585 Nine months ended Beginning balance $ 7,540 $ 1,751 $ 466 $ 12,932 $ 49 $ 2,463 $ 25,201 Provisions 4,212 230 350 10,550 10 969 16,321 Charge-offs (3,628 ) (9 ) — (5,740 ) (5 ) (1,932 ) (11,314 ) Recoveries 429 279 — 41 1 627 1,377 Ending balance $ 8,553 $ 2,251 $ 816 $ 17,783 $ 55 $ 2,127 $ 31,585 Ending balance: Individually evaluated for impairment $ 2,728 $ 39 $ — $ 6,795 $ — $ — $ 9,562 Collectively evaluated for impairment 4,458 1,612 802 10,169 53 2,127 19,221 Loans acquired with deteriorated credit quality 1,367 600 14 819 2 — 2,802 Total allowance for loan and lease losses $ 8,553 $ 2,251 $ 816 $ 17,783 $ 55 $ 2,127 $ 31,585 September 30, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Loans and leases ending balance: Individually evaluated for impairment $ 24,071 $ 2,374 $ — $ 26,731 $ — $ — $ 53,176 Collectively evaluated for impairment 1,139,782 637,320 276,437 1,257,082 9,087 183,184 3,502,892 Loans acquired with deteriorated credit quality 142,435 109,409 4,562 18,349 267 — 275,022 Total loans and leases $ 1,306,288 $ 749,103 $ 280,999 $ 1,302,162 $ 9,354 $ 183,184 $ 3,831,090 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 The Company increased the allowance for loan and lease losses by $453,000 and $6.4 million for the three and nine months ended September 30, 2019, respectively. 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. For acquired impaired loans, the Company decreased the allowance for loan and lease losses by $480,000 for the three months ended September 30, 2019. The Company increased the allowance for acquired impaired loan and lease losses by $260,000 for the The Company increased the allowance for loan and lease losses for acquired impaired loans 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 For loans individually evaluated for impairment, the Company increased the allowance for loan and lease losses by $276,000 and $2.9 million for the three and nine months ended September 30, 2019, respectively. The Company increased the allowance for loan and lease losses by $1.5 million and $2.5 million for the three and nine months ended September 30, 2018, respectively. For loans collectively evaluated for impairment, the Company increased the allowance for loan and lease losses by $850,000 and $3.4 million for the three and nine months ended September 30, 2019, respectively. The Company increased the allowance for loan and lease losses by $2.0 million and $5.1 million for the three and nine months ended September 30, 2018, respectively. The following and September 30, 2019 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 15,636 $ 16,653 $ — Residential real estate 2,246 2,356 — Commercial and industrial 9,557 10,510 — With an allowance recorded Commercial real estate 8,435 9,246 2,728 Residential real estate 128 146 39 Commercial and industrial 17,174 18,353 6,795 Total impaired loans $ 53,176 $ 57,264 $ 9,562 December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 6,110 $ 7,693 $ — Residential real estate 1,886 1,858 — Commercial and industrial 11,193 13,961 — With an allowance recorded Commercial real estate 5,873 6,313 2,191 Residential real estate 251 253 61 Commercial and industrial 10,601 11,153 4,397 Total impaired loans $ 35,914 $ 41,231 $ 6,649 The following tables summarize the average recorded investment and interest income recognized for loans and leases considered impaired, which excludes acquired impaired loans, for the nine months ended as follows: September 30, 2019 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 9,379 $ 761 Residential real estate 1,914 60 Commercial and industrial 11,889 482 With an allowance recorded Commercial real estate 8,238 479 Residential real estate 207 7 Commercial and industrial 13,543 668 Total impaired loans $ 45,170 $ 2,457 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 For purposes The following September 30, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 1,008,797 $ 608,106 $ 254,745 $ 1,034,730 $ 8,916 $ 179,954 $ 3,095,248 Watch 103,761 10,986 14,544 183,458 170 16 312,935 Special Mention 24,998 17,975 7,148 24,289 — 2,097 76,507 Substandard 26,297 2,627 — 41,336 1 595 70,856 Doubtful — — — — — 522 522 Loss — — — — — — — Total $ 1,163,853 $ 639,694 $ 276,437 $ 1,283,813 $ 9,087 $ 183,184 $ 3,556,068 December 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 1,009,041 $ 553,665 $ 147,123 $ 962,291 $ 9,997 $ 188,314 $ 2,870,431 Watch 76,276 29,522 31,376 112,996 3,302 80 253,552 Special Mention 17,602 5,656 3,071 34,314 — 1,794 62,437 Substandard 11,880 2,125 — 22,579 15 818 37,417 Doubtful — — — — — 247 247 Loss — — — — — — — Total $ 1,114,799 $ 590,968 $ 181,570 $ 1,132,180 $ 13,314 $ 191,253 $ 3,224,084 The following tables summarize contractual delinquency information for acquired non-impaired and originated loans and leases by category at September 30, 2019 and December 31, 2018: September 30, 2019 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 6,140 $ 2,449 $ — $ 12,186 $ 20,775 $ 1,143,078 $ 1,163,853 Residential real estate 632 501 — 2,092 3,225 636,469 639,694 Construction, land development, and other land — 3,203 — — 3,203 273,234 276,437 Commercial and industrial 9,136 1,018 — 24,592 34,746 1,249,067 1,283,813 Installment and other 12 — — 1 13 9,074 9,087 Lease financing receivables 651 460 — 657 1,768 181,416 183,184 Total $ 16,571 $ 7,631 $ — $ 39,528 $ 63,730 $ 3,492,338 $ 3,556,068 December 31, 2018 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 6,659 $ 2,145 $ — $ 9,484 $ 18,288 $ 1,096,511 $ 1,114,799 Residential real estate 4,488 711 — 1,815 7,014 583,954 590,968 Construction, land development, and other land — — — — — 181,570 181,570 Commercial and industrial 5,829 1,376 — 13,932 21,137 1,111,043 1,132,180 Installment and other 1,932 4 — 12 1,948 11,366 13,314 Lease financing receivables 789 530 — 591 1,910 189,343 191,253 Total $ 19,697 $ 4,766 $ — $ 25,834 $ 50,297 $ 3,173,787 $ 3,224,084 Trouble debt restructurings are granted due to borrower financial difficulty and provide for a modification of loan repayment terms. TDRs are treated in the same manner as impaired loans for purposes of calculating the allowance for loan and lease losses. The tables below present TDRs by loan category as of September 30, 2019 and December 31, 2018: September 30, 2019 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 5 $ 1,476 $ 1,476 $ — $ 179 Commercial and industrial 3 528 528 — 120 Residential real estate 2 200 200 — — Total accruing 10 2,204 2,204 — 299 Non-accruing: Commercial real estate 8 3,650 3,473 177 553 Commercial and industrial 10 7,493 5,622 1,871 1,268 Residential real estate 1 113 113 — — Total non-accruing 19 11,256 9,208 2,048 1,821 Total troubled debt restructurings 29 $ 13,460 $ 11,412 $ 2,048 $ 2,120 December 31, 2018 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 4 $ 1,508 $ 1,508 $ — $ 113 Commercial and industrial 2 191 191 — 100 Residential real estate 1 114 114 — — Total accruing 7 1,813 1,813 — 213 Non-accruing: Commercial real estate 9 2,512 2,471 41 743 Commercial and industrial 6 6,714 4,843 1,871 1,290 Total non-accruing 15 9,226 7,314 1,912 2,033 Total troubled debt restructurings 22 $ 11,039 $ 9,127 $ 1,912 $ 2,246 In addition, Loans modified and 2018: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Accruing: Beginning balance $ 1,529 $ 1,238 $ 1,813 $ 1,061 Additions — — 113 37 Net payments (242 ) (8 ) (291 ) (56 ) Net transfers from (to) non-accrual 917 — 569 188 Ending balance 2,204 1,230 2,204 1,230 Non-accruing: Beginning balance 7,834 5,776 7,314 1,570 Additions 2,893 1,667 4,321 7,123 Net payments (540 ) (84 ) (1,266 ) (1,002 ) Charge-offs (62 ) — (592 ) (144 ) Net transfers from (to) accrual (917 ) — (569 ) (188 ) Ending balance 9,208 7,359 9,208 7,359 Total troubled debt restructurings 11,412 8,589 11,412 8,589 Troubled debt restructurings that subsequently defaulted within twelve months of the restructure date during the three and nine months ended September 30, 2019 had a recorded investment of zero and $348,000, respectively. Troubled debt restructurings that subsequently defaulted within twelve months of the restructure date during the three and nine months ended September 30, 2018 had a recorded investment of zero and $340,000, respectively. At September 30, 2019 and December 31, 2018, the During the , the

Servicing Assets

Servicing Assets	9 Months Ended
	Sep. 30, 2019
Transfers And Servicing [Abstract]
Servicing Assets	Note 7—Servicing Activity for the three and nine months ended September 30, 2019 and 2018 is Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Beginning balance $ 19,760 $ 21,587 $ 19,693 $ 21,400 Additions, net 1,789 1,533 4,340 5,681 Changes in fair value (1,610 ) (2,446 ) (4,094 ) (6,407 ) Ending balance $ 19,939 $ 20,674 $ 19,939 $ 20,674 Loans serviced as of and were as follows: September 30, December 31, 2019 2018 Loan portfolios serviced for: SBA guaranteed loans $ 1,197,725 $ 1,151,915 USDA guaranteed loans 117,478 106,184 Total $ 1,315,203 $ 1,258,099 Loan servicing revenue totaled $2.7 and $2.6 million for the three months ended September 30, 2019 and 2018, respectively. Loan servicing revenue totaled $7.9 and $7.6 million for the nine months ended September 30, 2019 and 2018, respectively. Loan servicing asset revaluation, which represents the changes in fair value of servicing assets, resulted in downward valuations of $1.6 and $2.4 million for the three months ended September 30, 2019 and 2018, respectively. Loan servicing asset revaluation resulted in downward valuations of $4.1 and $6.4 million for the nine months ended September 30, 2019 and 2018, respectively. The fair Generally, as interest rates rise on variable rate loans, loan prepayments increase due to an increase in refinance activity, which may result in a decrease in the fair value of servicing assets. Measurement of fair value is limited to the conditions existing and the assumptions used as of a particular point in time, and those assumptions may change over time. Refer to Note 16—Fair Value Measurement for further details.

Other Real Estate Owned

Other Real Estate Owned	9 Months Ended
	Sep. 30, 2019
Banking And Thrift [Abstract]
Other Real Estate Owned	Note 8—Other Real Estate Owned The following table presents the change in other real estate owned (“OREO”) for the three and nine months ended September 30, 2019 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Beginning balance $ 8,070 $ 6,402 $ 5,314 $ 10,626 Acquisitions of OREO through business combination — — 2,201 — Net additions to OREO 1,840 307 3,916 1,527 Proceeds from sales of OREO (1,391 ) (2,008 ) (2,722 ) (7,130 ) Gains (losses) on sales of OREO 38 489 11 380 Valuation adjustments (26 ) (299 ) (189 ) (512 ) Ending balance $ 8,531 $ 4,891 $ 8,531 $ 4,891 At September 30, 2019 and December 31, 2018, the balance of real estate owned included $688,000 and $838,000, respectively, of foreclosed residential real estate properties recorded as a result of obtaining physical possession of the property. At September 30, 2019 and December 31, 2018, the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings were in process is $2.9 million and $2.3 million, respectively. Proceeds from sales of OREO include proceeds from internally financed sales of OREO of $183,000 for the nine months ended September 30, 2019. There were no internally financed sales of OREO for the three months ended September 30, 2019. Proceeds from internally financed sales of OREO were $444,000 for the nine months ended September 30, 2018. There were no internally financed sales of OREO for the three months ended September 30, 2018.

Goodwill, Core Deposit Intangib

Goodwill, Core Deposit Intangible and Other Intangible Assets	9 Months Ended
	Sep. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill, Core Deposit Intangible and Other Intangible Assets	Note 9—Goodwill, Core Deposit Intangible and Other Intangible Assets The following tables summarize the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the three and nine months ended September 30, 2019 and 2018: Nine Months Ended September 30, 2019 2018 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 128,177 $ 30,360 $ 3,059 $ 54,562 $ 16,720 $ — Additions 17,461 6,220 — 72,974 19,060 3,216 Amortization — (5,534 ) (200 ) — (3,685 ) (89 ) Ending balance $ 145,638 $ 31,046 $ 2,859 $ 127,536 $ 32,095 $ 3,127 Accumulated amortization N/A $ 24,420 $ 358 N/A $ 17,151 89 Weighted average remaining amortization period N/A 6.7 Years 10.7 Years N/A 7.1 Years 11.7 Years Three Months Ended September 30, 2019 2018 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 145,638 $ 32,982 $ 2,926 $ 127,536 $ 33,917 $ 3,194 Additions — — — — — — Amortization — (1,936 ) (67 ) — (1,822 ) (67 ) Ending balance $ 145,638 $ 31,046 $ 2,859 $ 127,536 $ 32,095 $ 3,127 Accumulated amortization N/A $ 24,420 $ 358 N/A $ 17,151 89 Weighted average remaining amortization period N/A 6.7 Years 10.7 Years N/A 7.1 Years 11.7 Years The Company added additional goodwill, core deposit intangible assets, and customer relationship intangible assets in conjunction with the Oak Park River Forest and First Evanston acquisitions. Please refer to Note 3—Acquisitions for further details. The following table presents the estimated amortization expense for core deposit intangible, customer relationship intangible, and other intangible assets recognized at September 30, 2019: Estimated Amortization 2019 $ 2,002 2020 7,577 2021 7,012 2022 6,440 2023 4,336 Thereafter 6,538 Total $ 33,905

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Income Taxes	Note 10—Income The Company uses an estimated annual effective tax rate method in computing its interim tax provision. This effective tax rate is based on forecasted annual pre-tax income, permanent tax differences and statutory tax rates. The effective tax rate for the nine months ended September 30, 2019 and 2018 was 27.7% and 24.4%, respectively. The Company recorded discrete income tax benefit of $64,000 and $362,000 related to the exercise of stock options and vesting of restricted shares for the nine months ended September 30, 2019 and 2018, respectively. The current effective tax rate reflects the passage of the Tax Cuts and Jobs Act (the “Tax Act”), which was enacted on December 22, 2017. Among other things, the Tax Act reduces the corporate federal income tax rate from 35% to 21%, effective January 1, 2018. Also on December 22, 2017, the SEC issued Staff Accounting Bulletin 118 (“SAB 118”), which provides guidance on accounting for the Tax Act’s impact. SAB 118 provides a measurement period, not to extend beyond one year from the date of enactment during which a company, acting in good faith, may complete the accounting for the impacts of the Tax Act. The Company recorded an additional discrete income tax benefit of $724,000 during the first quarter of 2018. This adjustment includes the impact of the federal income tax rate decrease due to the Tax Act (enacted on December 22, 2017) on our net deferred tax assets. Net deferred tax assets decreased to $33.4 million at compared to $35.6 million at . The net decrease in the total net deferred tax assets recorded as of was a result of $4.9 million in net deferred tax assets added related to the acquisition of Oak Park River Forest, offset by a decrease in net deferred tax assets related to unrealized losses on available-for-sale securities and utilization of operating loss carryforwards during the period

Deposits

Deposits	9 Months Ended
	Sep. 30, 2019
Deposits [Abstract]
Deposits	Note 11—Deposits The composition of deposits was as follows as of September 30, 2019 and December 31, 2018: September 30, December 31, 2019 2018 Non-interest-bearing demand deposits $ 1,221,431 $ 1,192,873 Interest-bearing checking accounts 372,049 296,339 Money market demand accounts 745,154 640,401 Other savings 471,878 476,418 Time deposits (below $250,000) 966,866 911,603 Time deposits ($250,000 and above) 302,936 232,282 Total deposits $ 4,080,314 $ 3,749,916 Time deposits of $250,000 or more included $81.0 million and $50.0 million of brokered deposits at September 30, 2019 and December 31, 2018, respectively.

Federal Home Loan Bank Advances

Federal Home Loan Bank Advances	9 Months Ended
	Sep. 30, 2019
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank Advances	Note 12—Federal The following September 30, December 31, 2019 2018 Federal Home Loan Bank advances $ 506,000 $ 425,000 Weighted average cost 2.05 % 2.56 % At September 30, 2019, fixed-rate advances totaled $506.0 million with interest rates ranging from 2.04% to 2.08% The Company’s required investment in FHLB stock is $4.50 for every $100 in advances. At and , the Bank has additional borrowing capacity from the FHLB of $1.4 billion and $1.3 billion, respectively, subject to the availability of proper collateral. The Company hedges

Other Borrowings

Other Borrowings	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Other Borrowings	Note 13—Other Borrowings The following is a summary of the Company’s other borrowings as of September 30, 2019 and December 31, 2018: September 30, December 31, 2019 2018 Securities sold under agreements to repurchase $ 32,290 $ 34,166 Line of credit — — Total $ 32,290 $ 34,166 Securities On On April 30, 2019, the Company drew on the line of credit for $5.7 million and selected the LIBOR plus 225 basis points interest rate option, which was the interest rate option at the time of the draw. The funds were utilized to repay a line of credit assumed as a result of the Oak Park River Forest acquisition. The Company repaid the $5.7 million outstanding balance of the line of credit in full on May 31, 2019. The following September 30, December 31, 2019 2018 Federal Reserve Bank of Chicago discount window line $ 419,086 $ 293,613 Available federal funds lines 105,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Junior Subordinated Debentures	Note 14—Junior Subordinated Debentures At September 30, 2019 and December 31, 2018, the Name of Trust Aggregate Principal Amount September 30, 2019 Aggregate Principal Amount December 31, 2018 Stated Maturity Contractual Rate at September 30, 2019 Interest Rate Spread Metropolitan $ 35,000 $ 35,000 March 4.93 % Three-month LIBOR + 2.79% RidgeStone Capital Trust I 1,500 1,500 June 30, 2033 6.38 % Five-year LIBOR + 3.50% First Evanston Bancorp Trust I 10,000 10,000 March 15, 2035 3.90 % Three-month LIBOR + 1.78% Total liability, at par 46,500 46,500 Discount (9,293 ) (9,732 ) Total liability, at carrying value $ 37,207 $ 36,768 In 2004, the As part of the Ridgestone acquisition, the Company assumed the obligations to RidgeStone Capital Trust I of $1.5 million in principal amount, which was formed for the issuance of trust preferred securities. Beginning on June 30, 2008, the interest rate reset to the five-year LIBOR plus 3.50% (6.38% at September 30, 2019 and December 31, 2018), which is in effect until June 30, 2023 and updated every five years. Interest is paid on a quarterly basis. The Company has the right to redeem the debentures, in whole or in part, on any interest payment date on or after June 30, 2008. As part of the First Evanston acquisition, the Company assumed the obligations to First Evanston Bancorp Trust I of $10.0 million in principal amount, which was formed for the issuance of trust preferred securities. Refer to Note 3—Acquisitions for additional information. Beginning on March 15, 2010, the interest rate reset to the three-month LIBOR plus 1.78% (3.90% and 4.57% at September 30, 2019 and December 31, 2018, respectively), which is in effect until the debentures mature in 2035. Interest is paid on a quarterly basis. The Company has the right to redeem the debentures, in whole or in part, on any interest payment date on or after March 2010. The Company has the option to defer interest payments on the debentures from time to time for a period not to exceed five consecutive years. Accrued The Trusts

Commitments and Contingent Liab

Commitments and Contingent Liabilities	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Note 15—Commitments Legal —I n th e ordinar y cours e o f business , th e Compan y an d Ban k hav e various outstandin g commitment s an d contingen t liabilitie s tha t ar e no t recognize d i n th e accompanyin g consolidated financia l statements . I n addition , th e Compan y ma y b e a defendan t i n certai n claim s an d lega l action s arisin g i n the ordinar y cours e o f business . I n th e opinio n o f management , afte r consultatio n wit h lega l counsel , th e ultimate dispositio n o f thes e matter s i s currentl y no t expecte d t o hav e a materia l advers e effec t o n th e Company’s Consolidated Financial Statements. Operating s —The Company has entered into various operating lease agreements primarily for facilities and land on which banking facilities are located. Certain lease agreements have renewal options at the end of the original lease term and certain lease agreements have escalation clauses in the rent payments. The minimum Minimum Commitments 2019 $ 1,166 2020 4,455 2021 3,798 2022 2,230 2023 1,294 Thereafter 3,303 Total $ 16,246 The Company’s During t C In June 2018, the Company accrued $8.1 million in data processing expense primarily related to contract termination with its core service provider in anticipation of a future system conversion Commitments t —The Company is party to financial instruments with off-balance sheet risk in the normal course of business to meet the financing needs of its customers. These financial instruments include commitments to extend credit and standby letters of credit. Those instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the Consolidated Statements of Financial Condition. The contractual or notional amounts of those instruments reflect the extent of involvement the Company has in particular classes of financial instruments. The Company’s exposure The following September 30, 2019 December 31, 2018 Fixed Rate Variable Total Fixed Variable Total Commitments to extend credit $ 51,101 $ 930,778 $ 981,879 $ 74,099 $ 928,991 $ 1,003,090 Letters of credit 784 39,724 40,508 1,982 34,071 36,053 Total $ 51,885 $ 970,502 $ 1,022,387 $ 76,081 $ 963,062 $ 1,039,143 Commitments to extend credit are agreements to lend to a customer as long as there is no violation of any condition established in the contract. Commitments generally have fixed expiration dates or other termination clauses and may require payment of a fee. Since many of the commitments are expected to expire without being drawn upon, the total commitment amount does not necessarily represent future cash requirements. The Company evaluates each customer’s creditworthiness on a case-by-case basis. The amount of collateral obtained, if deemed necessary by the Company upon extension of credit, is based on management’s credit evaluation of the counterparty. Collateral is primarily obtained in the form of commercial and residential real estate (including income producing commercial properties). Letters Commitments

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurement	Note 16—Fair Value Measurement Fair These types Level 1 —Quoted prices in active markets for identical assets or liabilities. Level 2 —Quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active and model-derived valuations whose inputs are observable or whose significant value drivers are observable. Level 3 —Unobservable inputs that are supported by little or no market activity and that are significant to the fair value of the asset or liability. Unobservable inputs are used to measure fair value to the extent that observable inputs are not available. The Company’s own data used to develop unobservable inputs may be adjusted for market considerations when reasonably available. The The Company used the Securities e —The Company obtains fair value measurements from an independent pricing service. Management reviews the procedures used by the third party, including significant inputs used in the fair value calculations. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. When market quotes are not readily accessible or available, alternative approaches are utilized, such as matrix or model pricing. The Company’s methodology for pricing non-rated bonds focuses on three distinct inputs: equivalent rating, yield and other pricing terms. To determine the rating for a given non-rated municipal bond, the Company references a publicly issued bond by the same issuer if available as well as other additional key metrics to support the credit worthiness. Typically, pricing for these types of bonds would require a higher yield than a similar rated bond from the same issuer. A reduction in price is applied to the rating obtained from the comparable bond, as the Company believes if liquidated, a non-rated bond would be valued less than a similar bond with a verifiable rating. The reduction applied by the Company is one notch lower (i.e. a “AA” rating for a comparable bond would be reduced to “AA-” for the Company’s valuation). In 2019 and 2018, all of the ratings derived by the Company were “BBB” or better with and without comparable bond proxies. The fair value measurement of municipal bonds is sensitive to the rating input, as a higher rating typically results in an increased valuation. The remaining pricing inputs used in the bond valuation are observable. Based on the rating determined, the Company obtains a corresponding current market yield curve available to market participants. Other terms including coupon, maturity date, redemption price, number of coupon payments per year, and accrual method are obtained from the individual bond term sheets. Equity and other securities —The Company utilizes the same fair value measurement methodology for equity and other securities as detailed in the securities available-sale portfolio above. Servicing s —Fair value is based on a loan-by-loan basis taking into consideration the original term to maturity, the current age of the loan and the remaining term to maturity. The valuation methodology utilized for the servicing assets begins with generating estimated future cash flows for each servicing asset, based on their unique characteristics and market-based assumptions for prepayment speeds and costs to service. The present value of the future cash flows are then calculated utilizing market-based discount rate assumptions. Derivative s —Interest rate derivatives are valued by a third party, using models that primarily use market observable inputs, such as yield curves, and are validated by comparison with valuations provided by the respective counterparties. Derivative financial instruments are included in other assets and other liabilities in the Consolidated Statements of Financial Condition. The following Fair Value Measurements Using September 30, 2019 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 42,842 $ 42,842 $ — $ — U.S. Government agencies 177,858 — 177,858 — Obligations of states, municipalities, and political subdivisions 98,602 — 98,407 195 Mortgage-backed securities; residential Agency 329,010 — 329,010 — Non-Agency 120,060 — 120,060 — Mortgage-backed securities; commercial Agency 152,033 — 152,033 — Non-Agency 31,500 — 31,500 — Corporate securities 47,194 — 47,194 — Other securities 32,834 — 32,834 — Equity and other securities, at fair value Mutual funds 2,944 2,944 — — Equity securities 4,704 — 4,008 696 Servicing assets 19,939 — — 19,939 Derivative assets 10,288 — 10,288 — Financial liabilities Derivative liabilities 11,093 — 11,093 — Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 52,667 $ 52,667 $ — $ — U.S. Government agencies 186,498 — 186,498 — Obligations of states, municipalities, and political subdivisions 60,233 — 60,038 195 Mortgage-backed securities; residential Agency 272,963 — 272,963 — Non-Agency 83,621 — 83,621 — Mortgage-backed securities; commercial Agency 90,434 — 90,434 — Non-Agency 30,458 — 30,458 — Corporate securities 34,173 — 34,173 — Other securities 6,609 2,844 3,074 691 Servicing assets 19,693 — — 19,693 Derivative assets 10,740 — 10,740 — Financial liabilities Derivative liabilities 4,243 — 4,243 — The The area The Company did not have any transfers nine months ended and 2018 The following table presents additional information about financial assets measured at fair value on recurring basis for which the Company used significant unobservable inputs (Level 3): Nine Months Ended September 30, 2019 2018 2019 2018 Investment Securities Servicing Assets Balance, beginning of period $ 886 $ 1,052 $ 19,693 $ 21,400 Acquired assets at fair value — 314 — — Additions, net — — 4,340 5,680 Amortization 4 4 — — Change in unrealized gain 1 11 — — Change in fair value — — (4,094 ) (6,406 ) Balance, end of period $ 891 $ 1,381 $ 19,939 $ 20,674 The following Financial Instruments Valuation Technique Unobservable Inputs Range of Inputs Weighted Average Range Impact to Valuation from an Increased or Higher Input Value Obligations of states, municipalities, and political obligations Discounted Probability of default 2.4% 2.4% Decrease Single issuer trust preferred Discounted cash flow Probability of default 4.9%—5.4% 5.8% Decrease Servicing assets Discounted cash flow Prepayment speeds 2.7%—21.9% 13.7% Decrease Discount rate 4.8%—24.0% 12.2% Decrease Expected weighted average loan life 0.1—9.5 years 4.5 years Increase The Company used the Impaired ) —Impaired loans, other than those existing on the date of a business acquisition, are primarily carried at the fair value of the underlying collateral, less estimated costs to sell, if the loan is collateral dependent. Valuations of impaired loans that are collateral dependent are supported by third party appraisals in accordance with the Bank’s credit policy. Other valuation methods include analysis of discounted cash flows, which measures the present value of expected future cash flows discounted at the loan’s effective interest rate. Impaired loans that are not collateral dependent are not material. Assets e —Assets held for sale consist of former branch locations and real estate previously purchased for expansion. Assets are considered held for sale when management has approved to sell the assets following a branch closure or other events. The properties are being actively marketed and transferred to assets held for sale based on the lower of carrying value or its fair value, less estimated costs to sell. Other d —Certain assets held within other real estate owned represent real estate or other collateral that has been adjusted to its estimated fair value, less cost to sell, as a result of transferring from the loan portfolio at the time of foreclosure or repossession and based on management’s periodic impairment evaluation. From time to time, non-recurring fair value adjustments to other real estate owned are recorded to reflect partial write-downs based on an observable market price or current appraised value of property. Adjustments Fair Value Measurements Using September 30, 2019 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 21,343 $ — $ — $ 21,343 Residential real estate 2,335 — — 2,335 Commercial and industrial 19,936 — — 19,936 Assets held for sale 15,472 — — 15,472 Other real estate owned 8,531 — — 8,531 Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 9,792 $ — $ — $ 9,792 Residential real estate 2,076 — — 2,076 Commercial and industrial 17,397 — — 17,397 Assets held for sale 14,489 — — 14,489 Other real estate owned 5,314 — — 5,314 The following Cash and cash equivalent s —For these short-term instruments, the carrying amount is a reasonable estimate of fair value. Securities y —The Company obtains fair value measurements from an independent pricing service. Management reviews the procedures used by the third party, including significant inputs used in the fair value calculations. The fair value measurements consider observable data that may include dealer quotes, market spreads, cash flows, the U.S. Treasury yield curve, live trading levels, trade execution data, market consensus prepayment speeds, credit information and the bond’s terms and conditions, among other things. When market quotes are not readily accessible or available, alternative approaches are utilized, such as matrix or model pricing. Restricted k —The fair value has been determined to approximate cost. Loans held for — The fair value of loans held for sale are based on quoted market prices, where available, and determined by discounted estimated cash flows using interest rates approximating the Company’s current origination rates for similar loans adjusted to reflect the inherent credit risk. Loan —For certain variable rate loans that reprice frequently and with no significant changes in credit risk, fair value is estimated at carrying value. The fair value of other types of loans is estimated using an exit price notion for 2019 values. It 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 not carried at fair value September 30, December 31, Fair Value 2019 2018 Hierarchy Level Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets Cash and due from banks 1 $ 75,275 $ 75,275 $ 30,190 $ 30,190 Interest bearing deposits with other banks 2 33,564 33,564 91,670 91,670 Securities held-to-maturity 2 4,417 4,503 99,266 97,739 Other restricted stock 2 24,331 24,331 19,202 19,202 Loans held for sale 3 7,176 7,922 19,827 21,654 Loans and lease receivables, net (less impaired loans at fair value (1) 3 3,755,891 3,677,608 3,447,160 3,407,652 Accrued interest receivable 3 13,013 13,013 10,863 10,863 Financial liabilities Non-interest-bearing deposits 2 1,221,431 1,221,431 1,192,873 1,192,873 Interest-bearing deposits 2 2,858,883 2,867,646 2,557,043 2,554,329 Accrued interest payable 2 4,778 4,778 3,484 3,484 Line of credit 2 — — — — Federal Home Loan Bank advances 2 506,000 506,000 425,000 425,000 Securities sold under repurchase agreement 2 32,290 32,290 34,166 34,166 Junior subordinated debentures 3 37,207 42,496 36,768 42,351 (1) In accordance with the prospective adoption of ASU 2016-01, the fair value of loans and lease receivables, net (less impaired loans at fair value) as of September 30, 2019 was measured using an exit price notion. The fair value as of December 31, 2018 was measured using an entry price notion.

Derivative Instruments and Hedg

Derivative Instruments and Hedge Activities	9 Months Ended
	Sep. 30, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedge Activities	Note 17—Derivative Instruments and Hedge Activities The Company recognizes derivative financial instruments at fair value regardless of the purpose or intent for holding the instrument. The Company records derivative assets and derivative liabilities on the Consolidated Statements of Financial Condition within accrued interest receivable and other assets and accrued interest payable and other liabilities, respectively. The following tables present the fair value of the Company’s derivative financial instruments and classification on the Consolidated Statements of Financial Condition as of September 30, 2019 and December 31, 2018: September 30, 2019 December 31, 2018 Fair Value Fair Value Notional Amount Other Assets Other Liabilities Notional Amount Other Assets Other Liabilities Derivatives designated as hedging instruments Interest rate swaps designated as cash flow hedges $ — $ — $ — $ 250,000 $ 6,699 $ — Derivatives not designated as hedging instruments Other interest rate derivatives 296,656 10,288 11,076 294,545 4,041 4,237 Other credit derivatives 9,519 — 17 4,424 — 6 Total derivatives $ 306,175 $ 10,288 $ 11,093 $ 548,969 $ 10,740 $ 4,243 Interest rate swaps designated as cash flow hedges —Cash flow hedges of interest payments associated with certain FHLB advances had notional amounts totaling $250.0 million as of December 31, 2018. There were no cash flow hedges outstanding at September 30, 2019. 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. In September 2019, the Company terminated $250.0 million interest rate swaps designated as cash flow hedges, which were executed to reduce interest rate risk in a declining rate environment. The transaction resulted in a net loss of $383,000, net of tax, which was the clean value at the termination date. As of September 30, 2019, the remaining balance in accumulated other comprehensive income was $378,000, which will be amortized over the original life of the cash flow hedge. Interest recorded on these swap transactions reduced FHLB interest expense by $364,000 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, 2019 September 30, 2018 Amount of Loss Recognized in OCI Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Amount of Gain Recognized in OCI Amount of Gain Reclassified from OCI to Income as an Increase to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Interest rate swaps $ (5,484 ) $ 1,643 $ — $ 6,702 $ 863 $ — Other interest rate derivatives —The total combined notional amount was $296.7 million as of September 30, 2019 with maturities ranging from April 2020 to January 2030. The fair values of the interest rate derivative agreements are reflected in other assets and other liabilities with corresponding gains or losses reflected in non-interest income. During the three months ended September 30, 2019 and 2018, there were $170,000 and $230,000 of transaction fees, respectively, included in other non-interest income, related to these derivative instruments. During the nine months ended September 30, 2019 and 2018, there were $886,000 and $1.2 million of transaction fees, respectively, related to these derivative instruments. The following table reflects other interest rate derivatives as of September 30, 2019: Notional amounts $ 296,656 Derivative assets fair value 10,288 Derivative liabilities fair value 11,076 Weighted average pay rates 4.74 % Weighted average receive rates 4.37 % Weighted average maturity 6.8 years Other credit derivatives— The total notional amount was $9.5 million and $4.4 million as of September 30, 2019 and December 31, 2018, respectively. The fair value of the other credit derivatives are reflected in other liabilities with corresponding gains or losses reflected in non-interest income. The credit valuation adjustment (“CVA”) related to the other credit derivatives resulted in a decrease to other non-interest income of $7,000 and $1,000 during the three months ended September 30, 2019 and 2018, respectively. There were $73,000 and $35,000 of transaction fees included in non-interest income related to these derivative instruments during the three months ended September 30, 2019 and 2018, respectively. The CVA related to the other credit derivatives resulted in a decrease to other non-interest income of $11,000 and $4,000 during the nine months ended September 30, 2019 and 2018, respectively. There were $73,000 and $61,000 of transaction fees included in non-interest income related to these derivative instruments during the nine months ended September 30, 2019 and 2018, 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. 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, 2019, the CVA resulted in a decrease to non-interest income of $219,000. During the three months ended September 30, 2018, CVA resulted in an increase to non-interest income of $13,000. During the nine months ended September 30, 2019 and 2018, the CVA resulted in a decrease to non-interest income of $592,000 and $25,000, respectively. 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. The 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, 2019 December 31, 2018 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 10,288 $ 11,093 $ 10,740 $ 4,243 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 10,288 $ 11,093 $ 10,740 $ 4,243 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (1 ) (1 ) (2,823 ) (2,823 ) Collateral posted (10,287 ) (11,092 ) (7,917 ) (1,317 ) Net credit exposure $ — $ — $ — $ 103 For purposes of this disclosure, the amount of posted collateral by the counterparties is limited to the amount offsetting the derivative asset and derivative liability.

Share-Based Compensation

Share-Based Compensation	9 Months Ended
	Sep. 30, 2019
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Share-Based Compensation	Note 18 – Share-Based Compensation In June 2017, the Company adopted the 2017 Omnibus Incentive Compensation Plan (the “Omnibus Plan”) in connection with our IPO. The Omnibus Plan provides for the grant of stock options, stock appreciation rights, restricted stock, restricted stock units, dividend equivalent rights and other equity-based, equity-related or cash-based awards. A total of 1,550,000 shares of our common stock have been reserved for issuance under the Omnibus Plan. As of September 30, 2019, there were 1,186,226 shares available for future grants under the Omnibus Plan. On July 6, 2017, in conjunction with the completion of the IPO, the Company granted 58,900 restricted shares of the Company’s common stock to certain key employees, pursuant to the Omnibus Plan. The restricted shares will cliff vest on the third anniversary of the grant date, subject to continued employment. A total of 11,898 restricted shares were also granted during the year ended December 31, 2017 in connection with the recruitment of employees. These restricted shares vest ratably over a four year period. During 2018, the Company granted 131,157 shares of restricted common stock, par value $0.01 per share. Of this total, 102,559 restricted shares will vest ratably over four years on each anniversary of the grant date, 15,165 restricted shares will vest ratably over three years on each anniversary of the grant date, and 2,268 restricted shares will vest on the first anniversary of the grant date, all subject to continued employment. In addition, 11,165 performance-based restricted shares were included in the 2018 grant. The number of shares which may be earned under the award is dependent upon the Company’s return on average assets over a three-year period ending December 31, 2020, measured in 2018 against the Company’s internal targets and for 2019 and 2020 against a peer group consisting of publicly-traded bank holding companies ranging in asset size from 50% to 200% of the Company’s total assets. Under the award, 25% of the shares will be earned at threshold performance, 100% will be earned at target and 50th percentile performance, and up to 125% of the shares with above target and 75th percentile performance. Any earned performance shares will vest on the third anniversary of the grant date. During 2019, the Company granted 192,199 shares of restricted common stock, par value $0.01 per share. Of this total, 115,496 restricted shares will vest ratably over four years on each anniversary of the grant date, 54,147 restricted shares will vest ratably over three years on each anniversary of the grant date, 683 restricted shares will vest on the first anniversary of the grant date, and 898 share have vested, all subject to continued employment. In addition, 20,975 performance-based restricted shares were included in the 2019 grants. The number of shares which may be earned under the award is dependent upon the Company’s return on average assets, weighted equally, over a three-year period ending December 31, 2021, measured against a peer group consisting of publicly-traded bank holding companies. Results will be measured cumulatively at the end of the three years. Any earned shares will vest on the third anniversary of the grant date. The following table discloses the changes in restricted shares for the nine months ended September 30, 2019: Omnibus Plan Number of Shares Weighted Average Grant Date Fair Value Beginning balance, January 1, 2019 196,480 $ 21.66 Granted 192,199 18.70 Vested (37,310 ) 22.01 Forfeited (27,880 ) 19.75 Ending balance outstanding at September 30, 2019 323,489 $ 20.03 A total of 37,310 restricted shares vested during the nine months ended September 30, 2019. The fair value of restricted shares that vested during the nine months ended September 30, 2019 was $699,000. A total of 2,975 restricted shares vested during the year ended December 31, 2018. The fair value of restricted shares that vested during the year ended December 31, 2018 was $62,000. The Company recognizes share-based compensation based on the estimated fair value of the restricted stock at the grant date. Share-based compensation expense is included in non-interest expense in the Consolidated Statements of Operations. The following table summarizes restricted stock compensation expense for the nine months ended September 30, 2019 and 2018: Nine Months Ended September 30, 2019 2018 Total share-based compensation - restricted stock $ 1,357 $ 638 Income tax benefit 378 178 Unrecognized compensation expense 4,917 3,379 Weighted-average amortization period remaining 2.8 years 3.1 years The fair value of the unvested restricted stock awards at September 30, 2019 was $5.8 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 1,449,072 shares remain outstanding under the BYB Plan at September 30, 2019. The types of stock options granted under the BYB Plan were Time Options and Performance Options. The exercise price of each option is equal to the fair value of the stock as of the date of grant. These option awards have vesting periods ranging from one to five years and have 10-year contractual terms. Stock volatility was computed as the average of the volatilities of peer group companies. The vesting of Time Options is conditional based on completion of service. Performance Options have conditional vesting based on either performance targets or market performance. Certain Performance Options’ performance goals will be satisfied (in whole or in part) if the Bank achieves various performance targets such as profitability, asset quality, and conditional based on market performance, as outlined in the BYB Plan. Each of the performance goals identified are measured for achievement (or failure to achieve) independent of each other. In October 2017, the Board of Directors determined that the Performance Option goals were satisfied, in whole, and these Performance Options converted to Time Options. As a result of the previous completion of service, 414,894 performance options vested on October 3, 2017. The fair values of the stock options were determined using the Black-Scholes-Merton model for Time Options and a Monte Carlo simulation model for Performance Options. The following table discloses the activity in shares subject to options and the weighted average exercise prices, in actual dollars, for the nine months ended September 30, 2019: BYB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 1,598,872 $ 11.84 $ 7,713 6.6 Exercised (89,000 ) 16.25 $ 253 Forfeited (60,800 ) 16.25 Ending balance outstanding at September 30, 2019 1,449,072 $ 11.38 $ 9,420 5.6 Exercisable at September 30, 2019 1,411,572 $ 11.25 $ 9,359 5.6 A total of 89,000 stock options were exercised during the nine months ended September 30, 2019. During the nine months ended September 30, 2019, proceeds from the exercise of stock options were $1.4 million and related tax benefit was $70,000. A total of 148,748 stock options were exercised during the year ended December 31, 2018. During the year ended December 31, 2018, proceeds from the exercise of stock options were $1.7 million and related tax benefit was $449,000. No stock options vested during the nine months ended September 30, 2019. The Company recognizes share-based compensation based on the estimated fair value of the option at the grant date. Forfeitures are estimated based upon industry standards. Share-based compensation expense is included in non-interest expense in the Consolidated Statements of Operations. The following table summarizes stock option compensation expense for the nine months ended September 30, 2019 and 2018: Nine Months Ended September 30, 2019 2018 Total share-based compensation (benefit) - stock options $ (119 ) $ 510 Income tax benefit (expense) (33 ) 142 Unrecognized compensation expense - stock options 21 209 Weighted-average amortization period remaining 0.5 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 in the First Evanston Bancorp, Inc. Stock Incentive Plan (the “FEB Plan”) ceased to represent a right to acquire shares of First Evanston common stock and was assumed and converted automatically into a fully vested and exercisable adjusted option to purchase shares of Byline common stock (each an “Adjusted Option”). In accordance with the Merger Agreement, the number of shares of Byline common stock to which each such Adjusted Option relates is equal to the product (rounded down to the nearest whole share of Byline common stock) of: (a) the number of shares of First Evanston common stock subject to the First Evanston Option immediately prior to May 31, 2018, multiplied by (ii) 4.725. Each Adjusted Option has an exercise price per share of Byline common stock equal to the quotient (rounded up to the nearest whole cent) of (x) the per share exercise price of such First Evanston Option immediately prior to May 31, 2018, divided by (y) 4.725. The description of the conversion process is based on, and qualified by, the Merger Agreement. The following table discloses the activity in shares subject to options under the FEB Plan and the weighted average exercise prices, in actual dollars, for the nine months ended September 30, 2019: FEB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 624,383 $ 11.31 $ 3,339 5.2 Granted — Expired — Exercised (81,182 ) 11.24 $ 677 Forfeited — Ending balance outstanding at September 30, 2019 543,201 $ 11.32 $ 3,561 4.5 Exercisable at September 30, 2019 543,201 $ 11.32 $ 3,561 4.5 A total of 81,182 stock options were exercised during the nine months ended September 30, 2019. During the nine months ended September 30, 2019, proceeds from the exercise of stock options were $912,000 and related tax benefit was $189,000. A total of 56,404 stock options were exercised during the year ended December 31, 2018. During the year ended December 31, 2018, proceeds from the exercise of stock options were $601,000 and related tax benefit was $168,000. All shares of restricted performance shares of First Evanston common stock (“restricted stock”) that were previously issued under and held by Participants in the FEB Plan prior to the Merger were converted into the right to receive the per share merger consideration in connection with the Merger and pursuant to the Merger Agreement. Accordingly, no shares of First Evanston restricted stock remain outstanding under the FEB Plan. On April 30, 2019, the Company completed the acquisition of Oak Park River Forest. On May 15, 2019, the Company made a cash payment of $4.2 million for 35,870 outstanding Oak Park River Forest options to participants who elected to receive a cash payment in lieu of converting the options to the Omnibus plan.

Earnings per Share

Earnings per Share	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings per Share	Note 19—Earnings per Share A reconciliation of the numerators and denominators for earnings per common share computations is presented below. Incremental shares represent outstanding stock options for which the exercise price is less than the average market price of the Company’s common stock during the periods presented. Options to purchase 1,992,273 and 2,312,294 shares of common stock were outstanding as of September 30, 2019 and 2018, respectively. There were 323,489 and 194,455 restricted stock awards outstanding at September 30, 2019 and 2018, 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, 2019 2018 2019 2018 Net income $ 15,342 $ 14,536 $ 41,150 $ 24,072 Less: Dividends on preferred shares 196 196 587 587 Net income available to common stockholders $ 15,146 $ 14,340 $ 40,563 $ 23,485 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 37,831,356 36,042,914 37,094,083 32,341,087 Incremental shares 655,824 915,295 724,785 947,570 Weighted-average common stock outstanding (dilutive) 38,487,180 36,958,209 37,818,868 33,288,657 Basic earnings per common share $ 0.40 $ 0.40 $ 1.09 $ 0.73 Diluted earnings per common share $ 0.39 $ 0.39 $ 1.07 $ 0.71

Stockholders' Equity

Stockholders' Equity	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Stockholders' Equity	Note 20—Stockholders’ Equity A summary of the Company’s preferred and common stock at September 30, 2019 and December 31, 2018 is as follows: September 30, December 31, 2019 2018 Series B 7.5% fixed to floating non-cumulative perpetual preferred stock Par value $ 0.01 $ 0.01 Shares authorized 50,000 50,000 Shares issued 10,438 10,438 Shares outstanding 10,438 10,438 Common stock, voting Par value $ 0.01 $ 0.01 Shares authorized 150,000,000 150,000,000 Shares issued 38,169,126 36,343,239 Shares outstanding 38,169,126 36,343,239 During 2016, the Company authorized and issued Series B 7.50% fixed-to-floating non-voting, noncumulative perpetual preferred stock with a liquidation preference of $1,000 per share, plus the amount of unpaid dividends, if any, which is redeemable at the Company’s option on or after March 31, 2022. Holders of Series B Preferred Stock do not have any rights to convert such stock into shares of any other class of capital stock of the Company. Holders of Series B Preferred Stock are entitled to receive a fixed dividend of 7.50% per annum from the original issue date through December 30, 2021, after which the dividend is paid at a floating rate of three-month LIBOR plus 5.41% per annum. The Company Series B Preferred Stock is included in Tier 1 capital for regulatory capital purposes and is redeemable at the option of the Company at a redemption price of $1,000 per share, plus any declared and unpaid dividends (i) in whole or part on any dividend payment date on or after March 31, 2022, and (ii) in whole but not in part prior to March 31, 2022, within 90 days following a regulatory event, as defined in the Certificate of Designations of the Company Series B Preferred Stock. The Company must receive approval of the Federal Reserve Board prior to any redemption of the Company Series B Preferred Stock. For the three months ended September 30, 2019 and 2018, the Company declared and paid dividends on the Series B preferred stock of $196,000. For the nine months ended September 30, 2019 and 2018, the Company declared and paid dividends on the Series B preferred stock of $587,000. On November 1, 2019, the Company announced that its Board of Directors approved a stock repurchase program authorizing the purchase of up to an aggregate of 1,250,000 shares of the Company’s outstanding common stock. The shares may, at the discretion of management, be repurchased from time to time in open market purchases as market conditions warrant or in privately negotiated transactions. The Company is not obligated to purchase any shares under the program, and the program may be discontinued at any time. The actual timing, number and share price of shares purchased under the repurchase program will be determined by the Company at its discretion and will depend on a number of factors, including the market price of the Company’s stock, general market and economic conditions and applicable legal requirements. The shares authorized to be repurchased represent approximately 3.3% of the Company’s outstanding common stock at September 30, 2019.

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	Note 21—Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) The following table summarizes the changes in accumulated other comprehensive income (loss) for the nine months ended September 30, 2019 and 2018: (dollars in thousands) Unrealized Gains (Losses) on Cash Flow Hedges Unrealized (Losses) on Available-for -Sale Securities Total Accumulated Other Comprehensive Income (Loss) Balance, January 1, 2018 $ 2,913 $ (8,000 ) $ (5,087 ) Reclassification of certain income tax effects from accumulated other comprehensive income 687 (1,450 ) (763 ) Other comprehensive income (loss), net of tax 4,213 (10,725 ) (6,512 ) Balance, September 30, 2018 $ 7,813 $ (20,175 ) $ (12,362 ) Balance, January 1, 2019 $ 4,763 $ (14,261 ) $ (9,498 ) Cumulative-effect adjustment (ASU 2016-01) — (1,440 ) (1,440 ) Other comprehensive income (loss), net of tax (5,142 ) 17,041 11,899 Balance, September 30, 2019 $ (379 ) $ 1,340 $ 961

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation	These unaudited interim condensed consolidated financial statements include the accounts of Byline Illinois state chartered These unaudited interim condensed consolidated financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America (“GAAP”) for interim financial information and in accordance with the instructions to Form 10-Q and Article 10 of Regulation S-X as promulgated by the Securities and Exchange Commission (“SEC”). In preparing these financial statements, the Company has evaluated events and transactions subsequent to September 30, 2019 for potential recognition or disclosure. In the opinion of management, all adjustments (consisting of normal recurring accruals) considered necessary for a fair presentation of the financial position and results of operations for the periods presented have been included. Certain information in footnote disclosures normally included in financial statements prepared in accordance with GAAP has been condensed or omitted pursuant to the rules and regulations of the SEC and the accounting standards for interim financial statements. These financial statements should be read in conjunction with the consolidated financial statements and notes thereto included in the Company’s Consolidated Financial Statements for the years ended December 31, 2018, 2017, and 2016. In accordance with the Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 855, “Subsequent Events,” the Company’s management has evaluated subsequent events for potential recognition or disclosure through the date of the issuance of these consolidated financial statements. The Company has one reportable segment. The Company’s chief operating decision maker evaluates the operations of the Company using consolidated information for purposes of allocating resources and assessing performance. Therefore, segments disclosures are not required. No subsequent events were identified that would have required a change to the consolidated financial statements or disclosure in the notes to the consolidated financial statements. Certain prior period amounts have been reclassified to conform to current period presentation. These reclassifications did not result in any changes to previously reported net income or stockholders’ equity.
Accounting Pronouncements Recently Adopted or Issued	The following reflect recent accounting pronouncements that have been adopted or are pending adoption by the Company. As the Company qualifies as an emerging growth company and has elected the extended transition period for complying with new or revised accounting pronouncements, it is not subject to new or revised accounting standards applicable to public companies during the extended transition period. The accounting pronouncements pending adoption below reflect effective dates for the Company as an emerging growth company with the extended transition period. Adopted Accounting Pronouncements Revenue from Contracts with Customers In May 2014, FASB issued Accounting Standards Update (“ASU”) No. 2014-09, deferred by ASU No. 2015-14 and clarifying standards, Revenue from Contracts with Customers , which creates Topics 606 and 610 and supersedes Topic 605, Revenue Recognition . The core principle of Topic 606 is that an entity recognizes revenue to depict the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services. In April 2016, FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing . The amendments in this ASU clarify the following two aspects of Topic 606: (1) identifying performance obligations and (2) licensing implementation guidance, while retaining the related principles for those areas. In May 2016, FASB issued ASU No. 2016-12, Narrow-Scope Improvements and Practical Expedients , amending ASC Topic 606, Revenue from Contracts with Customers . The amendments in this ASU affect only several narrow aspects of Topic 606. In November 2017, FASB issued ASU No. 2017-14, amending ASC Topic 606, Revenue from Contracts with Customers . The ASU amends the codification to incorporate additional previously issued guidance from the SEC. The SEC issued SAB 116 to bring existing SEC staff guidance into conformity with the FASB’s adoption of and amendments to ASC Topic 606. In general, the new guidance requires companies to use more judgment and make more estimates than under current guidance, including identifying performance obligations in the contract, estimating the amount of variable consideration to include in the transaction price and allocating the transaction price to each separate performance obligation. The new authoritative guidance was initially effective for reporting periods after January 1, 2017 but was deferred to January 1, 2018. Given our emerging growth status, the Company adopted this new guidance on January 1, 2019 using the full retrospective method, meaning the standard is applied to all periods presented in the financial statements with the cumulative effect of initially applying the standard recognized at the beginning of the earliest period presented. The majority of the Company’s revenue streams, including interest and dividend income, servicing fees, and gains on sales of loans and investments, are outside the scope of Topic 606. Revenue streams reported as fees and service charges on deposits, ATM and interchange fees, and wealth management and trust income are within the scope of Topic 606. The Company applied the requirements of Topic 606 to the revenue streams that are within its scope. The adoption of Topic 606 did not result in any changes in the either timing or amount of recognized; there was no cumulative effect adjustment to opening retained earnings as no material changes were identified in the timing of revenue recognition. However, the presentation of certain costs associated with our ATM and debit card income were offset against ATM and interchange income. This change in presentation resulted in $396,000 and $1.1 million of expenses for the three and nine months ended September 30, 2019, respectively, being netted against ATM and interchange fees and reported in non-interest income instead of as other non-interest expense in non-interest expense. In addition, to conform to the current period presentation, $241,000 and $837,000 of related expenses for the three and nine months ended September 30, 2018, respectively, were reclassified from other non-interest expense in non-interest expense to being netted against ATM and interchange fees in non-interest income. The Company elected to apply the practical expedient and therefore does not disclose information about remaining performance obligations that have an original expected term of one year or less and allows the Company to expense costs related to obtaining a contract as incurred when the amortization period would have been one year or less. The Company adopted ASU 2014-09 using the full retrospective approach. The following table presents the impact of adopting the new revenue standard on our Consolidated Statements of Operations for the periods presented (in thousands): For the Three Months Ended For the Three Months Ended September 30, 2019 September 30, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 973 $ 1,369 $ (396 ) $ 1,540 $ 1,781 $ (241 ) Non-interest expense: Other non-interest expense $ 2,679 $ 3,075 $ (396 ) $ 2,880 $ 3,121 $ (241 ) For the Nine Months Ended For the Nine Months Ended September 30, 2019 September 30, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 2,635 $ 3,757 $ (1,122 ) $ 3,303 $ 4,140 $ (837 ) Non-interest expense: Other non-interest expense $ 8,358 $ 9,480 $ (1,122 ) $ 6,769 $ 7,606 $ (837 ) Fees and service charges on deposits: Fees and service charges on deposits include transaction and non-transaction based deposit fees. Transaction based fees on deposit accounts are charged to deposit customers for specific services provided to the customer. These fees include such items as wire fees, official check fees, and overdraft fees. These are contracts specific to each individual transaction and do not extend beyond the individual transaction. The performance obligation is completed and the fees are recognized at the time the specific transactional service is provided to the customer. Non-transactional deposit fees are typically monthly account maintenance fees charged on deposit accounts. These are day-to-day contracts that can be cancelled by either party without notice. The performance obligation is satisfied and the fees are recognized on a monthly basis after the service period is completed. ATM and interchange fees: ATM fees represent fees earned when a foreign debit or ATM card is used in a Byline Bank ATM. These fees are assessed and paid at the time of each transaction as the performance obligation is satisfied, which is at the point in time that the transaction is performed and approved. Interchange fees represent fees earned when a debit card issued by the Bank is used to purchase goods or services at a merchant. The merchant's bank pays the Bank a default interchange rate set by MasterCard on a transaction by transaction basis. Interchange fees are assessed as the performance obligation is satisfied, which is at the point in time the card transaction is authorized. The performance obligation is satisfied and the fees are earned when the cost of the transaction is charged to the Bank cardholders’ card. Direct expenses associated with ATM and debit cards are recorded as a net reduction against the ATM and interchange income. Wealth management and trust income: Wealth management and trust income represents fees earned by the Bank for discretionary investment management, trust administration, fiduciary and/or custody services rendered. Fees vary and are based on a contract with the customer. Fee income is determined as a percentage of assets under management and is recognized over the period the underlying account is serviced. Although some trust appointments can last for generations, most contracts are generally cancellable at any time, with the customer subject to a pro-rated fee in the month of termination. Recognition and Measurement of Financial Assets and Financial Liabilities In January 2016, FASB issued ASU No. 2016-01, Recognition and Measurement of Financial Assets and Financial Liabilities . The amendments in this ASU require equity securities to be measured at fair value with changes in the fair value recognized through net income. The amendments allow equity investments that do not have readily determinable fair values to be remeasured at fair value under certain circumstances and require enhanced disclosures about those investments. The amendments simplify the impairment assessment of equity investments without readily determinable fair values. The amendments also eliminate the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet. The amendments require entities to adjust fair value disclosures for financial instruments to be reflected at an exit price. The amendments in this ASU require separate presentation in other comprehensive income of the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments. This amendment excludes from net income gains or losses that the entity may not realize because those financial liabilities are not usually transferred or settled at their fair values before maturity. The amendments in this ASU require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or in the accompanying notes to the financial statements. The Company adopted the provisions of ASU No. 2016-01 as of January 1, 2019. The adoption of this ASU resulted in the Company reclassifying $1.4 million from other comprehensive income to retained earnings, representing the unrealized gain, net of tax, on available-for-sale for sale equity securities at the date of adoption. The provisions of ASU No. 2016-01 require any future changes in fair value of equity securities to be recorded in the Consolidated Statements of Operations which could result in additional volatility in non-interest income. At December 31, 2018, the Company held $6.6 million of available-for-sale equity investment securities, which were previously reported as available-for-sale securities, at fair value, and are now reported as equity and other securities, at fair value. In addition, the adoption of this ASU resulted in changing how the Company estimates the fair value of portfolio loans and leases for disclosure purposes. Fair values are estimated first by stratifying the portfolios of loans and leases with similar financial characteristics. Loans and leases are segregated by type such as commercial real estate, residential mortgage, construction, land, and development, commercial and industrial, consumer and other. Each loan and lease category is further segmented into fixed- and adjustable-rate interest terms. An estimate of fair value is then calculated based on discounted cash flows using as a discount rate based on the current rate offered on similar products, plus an adjustment for liquidity to reflect the non-homogeneous nature of the loans and leases, as well as a quarterly loss rate based on historical losses to arrive at an estimated exit price fair value. Fair value for impaired loans and leases is also based on recent appraisals or estimated cash flows discounted using rates commensurate with risk associated with the estimated cash flows. Assumptions regarding credit risk, cash flows and discount rates are judgmentally determined using available market information and specific borrower information. Derivatives and Hedging (Topic 815) In August 2017, FASB issued ASU No. 2017-12, Targeted Improvements to Accounting for Hedging Activities . The amendments in this ASU better align an entity’s risk management activities and financial reporting for hedging relationships through changes to both the designation and measurement guidance for qualifying hedging relationships and the presentation of hedge results. The Company adopted the provisions of ASU No. 2017-12 on January 1, 2019. Upon adoption, the Company elected to reclassify $94.8 million of securities held-to-maturity to securities available-for-sale, which did not impact on the Consolidated Statements of Operations Compensation—Stock Compensation (Topic 718) In May 2017, the FASB issued ASU 2017-09, Scope of Modification Accounting . The amendments in the ASU provide guidance about which changes to the terms or conditions of a share-based payment award require an entity to apply modification accounting in Topic 718. An entity should account for the effects of a modification unless all of the following are met: (1) the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the modified award is the same as the fair value (or calculated value or intrinsic value, if such an alternative measurement method is used) of the original award immediately before the original award is modified. If the modification does not affect any of the inputs to the valuation technique that the entity uses to value the award, the entity is not required to estimate the value immediately before and after the modification. (2) the vesting conditions of the modified award are the same as the vesting conditions of the original award immediately before the original award is modified. (3) the classification of the modified award is an equity instrument or liability instrument is the same as the classification of the original award immediately before the original award is modified. The amendments are effective for annual periods, and interim periods within those annual periods, beginning after December 15, 2017. Early adoption is permitted, including adoption in any interim period, for reporting periods for which financial statements have not yet been issued. The amendments should be applied prospectively to an award modified on or after the adoption date. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-09 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. Statement of Cash Flows (Topic 230) In August 2016, FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments . There is diversity in practice in how certain cash receipts and cash payments are presented and classified in the statement of cash flows under Topic 230 and other Topics. This ASU addresses eight specific cash flow issues with the objective of reducing the existing diversity in practice. Those eight issues are (1) debt prepayment or debt extinguishment costs, (2) settlement of zero-coupon debt instruments or other debt instruments with coupon interest rates that are insignificant in relation to the effective interest rate of the borrowing, (3) contingent consideration payments made after a business combination, (4) proceeds from the settlement of insurance claims, (5) proceeds from the settlement of corporate-owned life insurance policies, including bank-owned life insurance policies, (6) distributions received from equity method investees, (7) beneficial interests in securitization transactions, and (8) separately identifiable cash flows and application of the predominance principle. Current GAAP either is unclear or does not include specific guidance on these eight cash flow classification issues. These amendments provide guidance for each of the eight issues, thereby reducing current and potential future diversity in practice. The amendments in this ASU are effective for fiscal years beginning after December 15, 2017, and interim periods within those fiscal years. Early adoption is permitted, including adoption in an interim period. Given the Company’s emerging growth company status, the new authoritative guidance will be effective for reporting periods after January 1, 2019. The Company adopted the provisions of ASU No. 2016-15 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. In November 2016, the FASB issued ASU No. 2016-18, Statement of Cash Flows (Topic 230), Restricted Cash Business Combinations (Topic 805) In January 2017, the FASB issued ASU No. 2017-01, Clarifying the Definition of a Business . The guidance clarifies the definition of a business to assist entities with evaluating whether transactions should be accounted for as acquisitions or disposals of assets or businesses. This guidance is effective for annual and interim periods beginning after December 15, 2017. Given our emerging growth status, the Company adopted the provisions of ASU No. 2017-01 on January 1, 2019, which did not have a material impact on the Company’s Consolidated Financial Statements. 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: for investments in certain entities that calculate net asset value, an entity is required to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse only if the investee has communicated the timing to the entity or announced the timing publicly; and clarify that the measurement uncertainty disclosure is to communicate information about the uncertainty in measurement as of the reporting date. The amendments add the following disclosure requirements: the changes in unrealized gains and losses for the period included in other comprehensive income for recurring Level 3 fair value measurements held at the end of the reporting period; and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. Early adoption is permitted. The Company early adopted these amendments in 2018, which did not have a material impact on the Company’s Consolidated Financial Statements. Issued Accounting Pronouncements Pending Adoption Leases (Topic 842) In February 2016, FASB issued ASU No. 2016-02, Leases . The amendments in this ASU require lessees to recognize the following for all leases (with the exception of short-term) at the commencement date: a lease liability, which is a lessee’s obligation to make lease payments arising from a lease, measured on a discounted basis; and a right-of-use asset, which is an asset that represents the lessee’s right to use, or control the use of, a specified asset for the lease term. The amendments in this ASU leave lessor accounting largely unchanged, although certain targeted improvements were made to align lessor accounting with the lessee accounting model. This ASU simplifies the accounting for sale and leaseback transactions primarily because lessees must recognize lease assets and lease liabilities. 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. In October 2019, FASB voted to defer the effective date of this ASU for entities not classified as Public Business Entities (PBEs). Our status as an emerging growth company makes us eligible for this deferral. Assuming the Company remains an emerging growth company, the proposed guidance will be effective for reporting periods after December 15, 2020, and interim periods with fiscal years beginning after December 15, 2021. The Company expects an increase in assets and liabilities as a result of recognizing additional right-of-use assets and liabilities under lease contracts in which the Company is lessee. While the Company has not quantified the impact of this ASU on its direct financing lease portfolio, it does not expect a material change in its accounting for the initial direct costs related to these leases. Financial Instruments—Credit Losses (Topic 326) In June 2016, FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments . Current GAAP requires an “incurred loss” methodology for recognizing credit losses that delays recognition until it is probable a loss has been incurred. The main objective of this ASU is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The amendments in this ASU replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The amendments in this ASU require a financial asset (or group of financial assets) measured at amortized cost basis to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) to present the net carrying value at the amount expected to be collected on the financial asset. The measurement of expected credit losses will be based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The amendments in this ASU broaden the information that an entity must consider in developing its expected credit loss estimate for assets measured either collectively or individually. The use of forecasted information incorporates more timely information in the estimate of expected credit loss, which will be more useful to users of the financial statements. In October 2019, FASB voted to defer the effective date of the ASU for entities not classified as PBEs. Once issued, the Company intends to exercise the extension applicable to emerging growth companies. The Company is in process of implementation and determining the impact that this ASU 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.

Accounting Pronouncements Rec_2

Accounting Pronouncements Recently Adopted or Issued (Tables)	9 Months Ended
	Sep. 30, 2019
Accounting Changes And Error Corrections [Abstract]
Impact of Adopting the New Revenue Standard on Consolidated Statements of Operations	The Company adopted ASU 2014-09 using the full retrospective approach. The following table presents the impact of adopting the new revenue standard on our Consolidated Statements of Operations for the periods presented (in thousands): For the Three Months Ended For the Three Months Ended September 30, 2019 September 30, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 973 $ 1,369 $ (396 ) $ 1,540 $ 1,781 $ (241 ) Non-interest expense: Other non-interest expense $ 2,679 $ 3,075 $ (396 ) $ 2,880 $ 3,121 $ (241 ) For the Nine Months Ended For the Nine Months Ended September 30, 2019 September 30, 2018 As Reported Balance without Adoption of ASC 606 Effect of Change As Reported Balance without Adoption of ASC 606 Effect of Change Non-interest income: ATM and interchange fees $ 2,635 $ 3,757 $ (1,122 ) $ 3,303 $ 4,140 $ (837 ) Non-interest expense: Other non-interest expense $ 8,358 $ 9,480 $ (1,122 ) $ 6,769 $ 7,606 $ (837 )

Acquisitions (Tables)

Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2019
Business Combinations [Abstract]
Summary of Fair Values of Assets and Liabilities Assumed as of Acquisition Dates	The following table presents a summary of the fair values of assets acquired and liabilities assumed as of the acquisition dates: Preliminary Estimates April 30, 2019 Oak Park River Forest May 31, 2018 First Evanston Assets Cash and cash equivalents $ 10,469 $ 47,378 Securities available-for-sale 30,343 128,063 Restricted stock 414 1,360 Loans 261,151 916,011 Premises and equipment 3,488 15,890 Other real estate owned 2,201 — Other intangible assets 6,220 22,276 Bank-owned life insurance 3,485 — Deferred tax assets, net 4,887 2,302 Other assets 1,256 8,845 Total assets acquired 323,914 1,142,125 Liabilities Deposits 290,171 1,022,268 Line of credit 5,655 — Federal Home Loan Bank advances 5,300 — Junior subordinated debentures — 8,497 Accrued expenses and other liabilities 4,766 5,844 Total liabilities assumed 305,892 1,036,609 Net assets acquired $ 18,022 $ 105,516 Consideration paid Common stock (2019 - 1,464,558 shares issued at $20.02 per share, 2018 - 6,682,850 shares issued at $21.62 per share) 29,320 144,483 Outstanding stock options converted to Byline stock options — 7,644 Cash paid 6,163 27,004 Total consideration paid 35,483 179,131 Goodwill $ 17,461 $ 73,615
Summary of Acquired Non-Impaired Loans as of Acquisition Dates	The following table presents the acquired non-impaired loans as of the acquisition dates: April 30, 2019 Oak Park River Forest May 31, 2018 First Evanston Fair value $ 212,587 $ 890,986 Gross contractual amounts receivable 275,553 1,057,374 Estimate of contractual cash flows not expected to be collected (1) 23,932 36,544 Estimate of contractual cash flows expected to be collected 251,621 1,020,830 (1) Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default.
Summary of Pro Forma Information for Results of Operations	The following table provides the unaudited pro forma information for the results of operations for the three and nine months ended September 30, 2019 and 2018, as if the acquisitions had occurred on January 1, 2018. The pro forma results combine the historical results of First Evanston and Oak Park River Forest into the Company’s Consolidated Statements of Operations, including the impact of certain acquisition accounting adjustments, which includes loan discount accretion, intangible assets amortization, deposit premium accretion, and borrowing, net of discount amortization. The pro forma results have been prepared for comparative purposes only and are not necessarily indicative of the results that would have been obtained had the acquisition actually occurred on January 1, 2018. No assumptions have been applied to the pro forma results of operations regarding possible revenue enhancements, provision for credit losses, expense efficiencies or asset dispositions. The acquisition-related expenses that have been recognized are included in net income in the following table for the three and nine months ended September 30, 2019 and 2018. For the Three Months Ended For the Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Total revenues (net interest income and non-interest income) $ 72,644 $ 69,019 $ 209,765 $ 200,371 Net income $ 15,342 $ 15,673 $ 45,138 $ 42,160 Earnings per share—basic $ 0.40 $ 0.41 $ 1.18 $ 1.11 Earnings per share—diluted $ 0.39 $ 0.40 $ 1.16 $ 1.08

Securities (Tables)

Securities (Tables)	9 Months Ended
	Sep. 30, 2019
Investments Debt And Equity Securities [Abstract]
Summary of Amortized Cost and Fair Values of Securities Available-for-sale, Held to Maturity and Equity and Other Securities	The following September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 42,381 $ 461 $ — $ 42,842 U.S. Government agencies 177,082 1,048 (272 ) 177,858 Obligations of states, municipalities, and political subdivisions 96,564 2,269 (231 ) 98,602 Residential mortgage-backed securities Agency 329,145 2,178 (2,313 ) 329,010 Non-agency 119,661 644 (245 ) 120,060 Commercial mortgage-backed securities Agency 150,891 1,698 (556 ) 152,033 Non-agency 31,224 276 — 31,500 Corporate securities 46,821 415 (42 ) 47,194 Other securities 32,955 — (121 ) 32,834 Total $ 1,026,724 $ 8,989 $ (3,780 ) $ 1,031,933 September 30, 2019 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 4,417 $ 85 $ — $ 4,502 Total $ 4,417 $ 85 $ — $ 4,502 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Available-for-sale U.S. Treasury Notes $ 52,775 $ 81 $ (189 ) $ 52,667 U.S. Government agencies 187,427 367 (1,296 ) 186,498 Obligations of states, municipalities, and political subdivisions 60,686 133 (586 ) 60,233 Residential mortgage-backed securities Agency 284,038 101 (11,176 ) 272,963 Non-agency 84,998 199 (1,576 ) 83,621 Commercial mortgage-backed securities Agency 93,543 55 (3,164 ) 90,434 Non-agency 31,458 — (1,000 ) 30,458 Corporate securities 34,716 67 (610 ) 34,173 Other securities 4,613 2,127 (131 ) 6,609 Total $ 834,254 $ 3,130 $ (19,728 ) $ 817,656 December 31, 2018 Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Held-to-maturity Obligations of states, municipalities, and political subdivisions $ 23,835 $ 40 $ (210 ) $ 23,665 Residential mortgage-backed securities Agency 40,082 93 (531 ) 39,644 Non-agency 35,349 — (919 ) 34,430 Total $ 99,266 $ 133 $ (1,660 ) $ 97,739
Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Available-for-sale and Held to Maturity	Gross unrealized losses and fair values, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position as of September 30, 2019 and December 31, 2018, are summarized as follows: Less than 12 Months 12 Months or Longer Total September 30, 2019 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Government agencies 5 $ 14,834 $ (163 ) $ 20,266 $ (109 ) $ 35,100 $ (272 ) Obligations of states, municipalities and political subdivisions 4 9,960 (226 ) 1,417 (5 ) 11,377 (231 ) Residential mortgage-backed securities Agency 40 32,436 (179 ) 204,649 (2,134 ) 237,085 (2,313 ) Non-agency 11 36,826 (62 ) 28,142 (183 ) 64,968 (245 ) Commercial mortgage-backed securities Agency 8 38,571 (256 ) 33,769 (300 ) 72,340 (556 ) Corporate securities 5 9,276 (42 ) — — 9,276 (42 ) Other securities 1 32,834 (121 ) — — 32,834 (121 ) Total 74 $ 174,737 $ (1,049 ) $ 288,243 $ (2,731 ) $ 462,980 $ (3,780 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Available-for-sale U.S. Treasury Notes 18 $ 23,835 $ (52 ) $ 9,865 $ (137 ) $ 33,700 $ (189 ) U.S. Government agencies 25 43,487 (80 ) 50,101 (1,216 ) 93,588 (1,296 ) Obligations of states, municipalities and political subdivisions 56 13,926 (97 ) 18,563 (489 ) 32,489 (586 ) Residential mortgage-backed securities Agency 42 4,288 (45 ) 254,121 (11,131 ) 258,409 (11,176 ) Non-agency 8 59,107 (1,378 ) 4,009 (198 ) 63,116 (1,576 ) Commercial mortgage-backed securities Agency 9 21,356 (447 ) 52,640 (2,717 ) 73,996 (3,164 ) Non-agency 5 — — 30,458 (1,000 ) 30,458 (1,000 ) Corporate securities 15 25,762 (342 ) 4,642 (268 ) 30,404 (610 ) Other securities 1 — — 2,844 (131 ) 2,844 (131 ) Total 179 $ 191,761 $ (2,441 ) $ 427,243 $ (17,287 ) $ 619,004 $ (19,728 ) Less than 12 Months 12 Months or Longer Total December 31, 2018 # of Securities Fair Value Unrealized Losses Fair Value Unrealized Losses Fair Value Unrealized Losses Held-to-maturity Obligations of states, municipalities, and political subdivisions 23 $ 8,127 $ (58 ) $ 8,792 $ (152 ) $ 16,919 $ (210 ) Residential mortgage-backed securities Agency 16 6,625 (150 ) 21,139 (381 ) 27,764 (531 ) Non-agency 7 21,499 (503 ) 12,931 (416 ) 34,430 (919 ) Total 46 $ 36,251 $ (711 ) $ 42,862 $ (949 ) $ 79,113 $ (1,660 )
Summary of Proceeds From Sales of Securities Available-for-sale and Associated Gains and Losses	The proceeds from all sales of securities three and nine months ended September 30, 2019 For the Three Months Ended For the Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Proceeds $ 32,509 $ — $ 92,103 $ 544 Gross gains 225 — 1,274 4 Gross losses 47 — 123 —
Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity	At September 30, 2019, the Amortized Cost Fair Value Equity and other securities, at fair value Due after ten years $ 697 $ 697 No defined maturity 6,951 6,951 Total $ 7,648 $ 7,648 Available-for-sale Due in one year or less $ 59,697 $ 59,875 Due from one to five years 123,941 125,158 Due from five to ten years 136,438 137,993 Due after ten years 75,727 76,304 Mortgage-backed securities 630,921 632,603 Total $ 1,026,724 $ 1,031,933 Held-to-maturity Due from one to five years $ 3,805 $ 3,873 Due from five to ten years 612 629 Total $ 4,417 $ 4,502

Loan and Lease Receivables (Tab

Loan and Lease Receivables (Tables)	9 Months Ended
	Sep. 30, 2019
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, 2019 2018 Commercial real estate $ 1,305,438 $ 1,261,594 Residential real estate 748,875 704,899 Construction, land development, and other land 281,868 186,258 Commercial and industrial 1,300,997 1,145,240 Installment and other 9,284 13,675 Lease financing receivables 180,273 187,797 Total loans and leases 3,826,735 3,499,463 Net unamortized deferred fees and costs 1,444 (1,293 ) Initial direct costs 2,911 3,456 Allowance for loan and lease losses (31,585 ) (25,201 ) Net loans and leases $ 3,799,505 $ 3,476,425 September 30, December 31, 2019 2018 Lease financing receivables Net minimum lease payments $ 196,163 $ 204,646 Unguaranteed residual values 1,379 1,535 Unearned income (17,269 ) (18,384 ) Total lease financing receivables 180,273 187,797 Initial direct costs 2,911 3,456 Lease financial receivables before allowance for lease losses $ 183,184 $ 191,253
Summary of Minimum Annual Lease Payments for Lease Financing Receivables	The minimum Minimum Lease Payments 2019 $ 18,025 2020 70,292 2021 51,235 2022 33,733 2023 17,614 Thereafter 5,264 Total $ 196,163
Summary of Balances for Each Respective Loan and Lease Category	The following September 30, 2019 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 772,559 $ 142,435 $ 391,294 $ 1,306,288 Residential real estate 497,839 109,409 141,855 749,103 Construction, land development, and other land 236,780 4,562 39,657 280,999 Commercial and industrial 1,096,400 18,349 187,413 1,302,162 Installment and other 7,818 267 1,269 9,354 Lease financing receivables 160,061 — 23,123 183,184 Total loans and leases $ 2,771,457 $ 275,022 $ 784,611 $ 3,831,090 December 31, 2018 Originated Acquired Impaired Acquired Non- Impaired Total Commercial real estate $ 652,234 $ 146,808 $ 462,565 $ 1,261,607 Residential real estate 466,309 113,934 124,659 704,902 Construction, land development, and other land 144,128 3,779 37,442 185,349 Commercial and industrial 803,508 12,617 328,672 1,144,797 Installment and other 11,718 404 1,596 13,718 Lease financing receivables 159,901 — 31,352 191,253 Total loans and leases $ 2,237,798 $ 277,542 $ 986,286 $ 3,501,626
Schedule of Estimated Fair Value of Impaired Loans Acquired at Acquisition	The following table presents a reconciliation of the undiscounted contractual cash flows, non-accretable difference, accretable yield, and fair value of acquired impaired loans as of the acquisition date of May 31, 2018 (First Evanston) and April 30, 2019 (Oak Park River Forest): First Evanston Oak Park River Forest Undiscounted contractual cash flows $ 33,594 $ 65,223 Undiscounted cash flows not expected to be collected (non-accretable difference) (5,003 ) (8,158 ) Undiscounted cash flows expected to be collected 28,591 57,065 Accretable yield at acquisition (3,566 ) (8,501 ) Estimated fair value of impaired loans acquired at acquisition $ 25,025 $ 48,564
Summary of Outstanding Balance and Carrying Amount of All Acquired Impaired Loans	The outstanding September 30, 2019 December 31, 2018 Outstanding Balance Carrying Value Outstanding Balance Carrying Value Commercial real estate $ 196,495 $ 142,435 $ 216,137 $ 146,808 Residential real estate 161,742 109,409 173,962 113,934 Construction, land development, and other land 13,276 4,562 11,962 3,779 Commercial and industrial 27,320 18,349 24,972 12,617 Installment and other 1,121 267 1,735 404 Total acquired impaired loans $ 399,954 $ 275,022 $ 428,768 $ 277,542
Summary of Changes in Accretable Yield for Acquired Impaired Loans	The following table summarizes the changes in accretable yield for acquired impaired loans for the three and nine months ended September 30, 2019 and 2018: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Beginning balance $ 46,538 $ 41,306 $ 37,115 $ 36,446 Additions — — 8,501 3,566 Accretion to interest income (7,703 ) (5,665 ) (17,772 ) (17,227 ) Reclassification from nonaccretable difference, net 5,153 2,507 16,144 15,363 Ending balance $ 43,988 $ 38,148 $ 43,988 $ 38,148
Schedule of Unpaid Principal Balance and Carrying Value for Acquired Non-Impaired Loans and Leases	The unpaid September 30, 2019 December 31, 2018 Unpaid Principal Balance Carrying Value Unpaid Principal Balance Carrying Value Commercial real estate $ 400,422 $ 391,294 $ 473,262 $ 462,565 Residential real estate 144,075 141,855 127,478 124,659 Construction, land development, and other land 40,778 39,657 38,494 37,442 Commercial and industrial 194,756 187,413 344,879 328,672 Installment and other 1,303 1,269 1,831 1,596 Lease financing receivables 24,754 23,123 32,977 31,352 Total acquired non-impaired loans and leases $ 806,088 $ 784,611 $ 1,018,921 $ 986,286

Allowance for Loan and Lease _2

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments (Tables)	9 Months Ended
	Sep. 30, 2019
Receivables [Abstract]
Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances	The following September 30, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Allowance for loan and lease losses Three months ended Beginning balance $ 8,934 $ 2,171 $ 691 $ 17,126 $ 67 $ 2,143 $ 31,132 Provisions 1,075 74 125 4,198 (12 ) 471 5,931 Charge-offs (1,459 ) — — (3,561 ) (1 ) (665 ) (5,686 ) Recoveries 3 6 — 20 1 178 208 Ending balance $ 8,553 $ 2,251 $ 816 $ 17,783 $ 55 $ 2,127 $ 31,585 Nine months ended Beginning balance $ 7,540 $ 1,751 $ 466 $ 12,932 $ 49 $ 2,463 $ 25,201 Provisions 4,212 230 350 10,550 10 969 16,321 Charge-offs (3,628 ) (9 ) — (5,740 ) (5 ) (1,932 ) (11,314 ) Recoveries 429 279 — 41 1 627 1,377 Ending balance $ 8,553 $ 2,251 $ 816 $ 17,783 $ 55 $ 2,127 $ 31,585 Ending balance: Individually evaluated for impairment $ 2,728 $ 39 $ — $ 6,795 $ — $ — $ 9,562 Collectively evaluated for impairment 4,458 1,612 802 10,169 53 2,127 19,221 Loans acquired with deteriorated credit quality 1,367 600 14 819 2 — 2,802 Total allowance for loan and lease losses $ 8,553 $ 2,251 $ 816 $ 17,783 $ 55 $ 2,127 $ 31,585 September 30, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Loans and leases ending balance: Individually evaluated for impairment $ 24,071 $ 2,374 $ — $ 26,731 $ — $ — $ 53,176 Collectively evaluated for impairment 1,139,782 637,320 276,437 1,257,082 9,087 183,184 3,502,892 Loans acquired with deteriorated credit quality 142,435 109,409 4,562 18,349 267 — 275,022 Total loans and leases $ 1,306,288 $ 749,103 $ 280,999 $ 1,302,162 $ 9,354 $ 183,184 $ 3,831,090 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
Summary of Recorded Investment, Unpaid Principal Balance, and Related Allowance for Loans and Leases Considered Impaired	The following and September 30, 2019 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 15,636 $ 16,653 $ — Residential real estate 2,246 2,356 — Commercial and industrial 9,557 10,510 — With an allowance recorded Commercial real estate 8,435 9,246 2,728 Residential real estate 128 146 39 Commercial and industrial 17,174 18,353 6,795 Total impaired loans $ 53,176 $ 57,264 $ 9,562 December 31, 2018 Recorded Investment Unpaid Principal Balance Related Allowance With no related allowance recorded Commercial real estate $ 6,110 $ 7,693 $ — Residential real estate 1,886 1,858 — Commercial and industrial 11,193 13,961 — With an allowance recorded Commercial real estate 5,873 6,313 2,191 Residential real estate 251 253 61 Commercial and industrial 10,601 11,153 4,397 Total impaired loans $ 35,914 $ 41,231 $ 6,649
Summary of Average Recorded Investment and Interest Income Recognized for Loans and Leases Considered Impaired	The following tables summarize the average recorded investment and interest income recognized for loans and leases considered impaired, which excludes acquired impaired loans, for the nine months ended as follows: September 30, 2019 Average Recorded Investment Interest Income Recognized With no related allowance recorded Commercial real estate $ 9,379 $ 761 Residential real estate 1,914 60 Commercial and industrial 11,889 482 With an allowance recorded Commercial real estate 8,238 479 Residential real estate 207 7 Commercial and industrial 13,543 668 Total impaired loans $ 45,170 $ 2,457 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
Summary of Risk Rating Categories of Loans and Leases Considered for Inclusion in Allowance for Loan and Lease Losses Calculation	The following September 30, 2019 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 1,008,797 $ 608,106 $ 254,745 $ 1,034,730 $ 8,916 $ 179,954 $ 3,095,248 Watch 103,761 10,986 14,544 183,458 170 16 312,935 Special Mention 24,998 17,975 7,148 24,289 — 2,097 76,507 Substandard 26,297 2,627 — 41,336 1 595 70,856 Doubtful — — — — — 522 522 Loss — — — — — — — Total $ 1,163,853 $ 639,694 $ 276,437 $ 1,283,813 $ 9,087 $ 183,184 $ 3,556,068 December 31, 2018 Commercial Real Estate Residential Real Estate Construction, Land Development, and Other Land Commercial and Industrial Installment and Other Lease Financing Receivables Total Pass $ 1,009,041 $ 553,665 $ 147,123 $ 962,291 $ 9,997 $ 188,314 $ 2,870,431 Watch 76,276 29,522 31,376 112,996 3,302 80 253,552 Special Mention 17,602 5,656 3,071 34,314 — 1,794 62,437 Substandard 11,880 2,125 — 22,579 15 818 37,417 Doubtful — — — — — 247 247 Loss — — — — — — — Total $ 1,114,799 $ 590,968 $ 181,570 $ 1,132,180 $ 13,314 $ 191,253 $ 3,224,084
Summary of Contractual Delinquency Information	The following tables summarize contractual delinquency information for acquired non-impaired and originated loans and leases by category at September 30, 2019 and December 31, 2018: September 30, 2019 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 6,140 $ 2,449 $ — $ 12,186 $ 20,775 $ 1,143,078 $ 1,163,853 Residential real estate 632 501 — 2,092 3,225 636,469 639,694 Construction, land development, and other land — 3,203 — — 3,203 273,234 276,437 Commercial and industrial 9,136 1,018 — 24,592 34,746 1,249,067 1,283,813 Installment and other 12 — — 1 13 9,074 9,087 Lease financing receivables 651 460 — 657 1,768 181,416 183,184 Total $ 16,571 $ 7,631 $ — $ 39,528 $ 63,730 $ 3,492,338 $ 3,556,068 December 31, 2018 30-59 Days Past Due 60-89 Days Past Due Greater than 90 Days and Accruing Non- accrual Total Past Due Current Total Commercial real estate $ 6,659 $ 2,145 $ — $ 9,484 $ 18,288 $ 1,096,511 $ 1,114,799 Residential real estate 4,488 711 — 1,815 7,014 583,954 590,968 Construction, land development, and other land — — — — — 181,570 181,570 Commercial and industrial 5,829 1,376 — 13,932 21,137 1,111,043 1,132,180 Installment and other 1,932 4 — 12 1,948 11,366 13,314 Lease financing receivables 789 530 — 591 1,910 189,343 191,253 Total $ 19,697 $ 4,766 $ — $ 25,834 $ 50,297 $ 3,173,787 $ 3,224,084
Summary of TDR's by Loan Category	The tables below present TDRs by loan category as of September 30, 2019 and December 31, 2018: September 30, 2019 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 5 $ 1,476 $ 1,476 $ — $ 179 Commercial and industrial 3 528 528 — 120 Residential real estate 2 200 200 — — Total accruing 10 2,204 2,204 — 299 Non-accruing: Commercial real estate 8 3,650 3,473 177 553 Commercial and industrial 10 7,493 5,622 1,871 1,268 Residential real estate 1 113 113 — — Total non-accruing 19 11,256 9,208 2,048 1,821 Total troubled debt restructurings 29 $ 13,460 $ 11,412 $ 2,048 $ 2,120 December 31, 2018 Number of Loans Pre-Modification Outstanding Recorded Investment Post-Modification Outstanding Recorded Investment Charge-offs Specific Reserves Accruing: Commercial real estate 4 $ 1,508 $ 1,508 $ — $ 113 Commercial and industrial 2 191 191 — 100 Residential real estate 1 114 114 — — Total accruing 7 1,813 1,813 — 213 Non-accruing: Commercial real estate 9 2,512 2,471 41 743 Commercial and industrial 6 6,714 4,843 1,871 1,290 Total non-accruing 15 9,226 7,314 1,912 2,033 Total troubled debt restructurings 22 $ 11,039 $ 9,127 $ 1,912 $ 2,246
Summary of Loans Modified as Troubled Debt Restructurings	Loans modified and 2018: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 Accruing: Beginning balance $ 1,529 $ 1,238 $ 1,813 $ 1,061 Additions — — 113 37 Net payments (242 ) (8 ) (291 ) (56 ) Net transfers from (to) non-accrual 917 — 569 188 Ending balance 2,204 1,230 2,204 1,230 Non-accruing: Beginning balance 7,834 5,776 7,314 1,570 Additions 2,893 1,667 4,321 7,123 Net payments (540 ) (84 ) (1,266 ) (1,002 ) Charge-offs (62 ) — (592 ) (144 ) Net transfers from (to) accrual (917 ) — (569 ) (188 ) Ending balance 9,208 7,359 9,208 7,359 Total troubled debt restructurings 11,412 8,589 11,412 8,589

Servicing Assets (Tables)

Servicing Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Transfers And Servicing [Abstract]
Activity for Servicing Assets and Related Changes in Fair Value	Activity for the three and nine months ended September 30, 2019 and 2018 is Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Beginning balance $ 19,760 $ 21,587 $ 19,693 $ 21,400 Additions, net 1,789 1,533 4,340 5,681 Changes in fair value (1,610 ) (2,446 ) (4,094 ) (6,407 ) Ending balance $ 19,939 $ 20,674 $ 19,939 $ 20,674
Unpaid Principal Balances of Loans Serviced for Others	The unpaid as of and were as follows: September 30, December 31, 2019 2018 Loan portfolios serviced for: SBA guaranteed loans $ 1,197,725 $ 1,151,915 USDA guaranteed loans 117,478 106,184 Total $ 1,315,203 $ 1,258,099

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	9 Months Ended
	Sep. 30, 2019
Banking And Thrift [Abstract]
Change in Other Real Estate Owned	The following table presents the change in other real estate owned (“OREO”) for the three and nine months ended September 30, 2019 Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Beginning balance $ 8,070 $ 6,402 $ 5,314 $ 10,626 Acquisitions of OREO through business combination — — 2,201 — Net additions to OREO 1,840 307 3,916 1,527 Proceeds from sales of OREO (1,391 ) (2,008 ) (2,722 ) (7,130 ) Gains (losses) on sales of OREO 38 489 11 380 Valuation adjustments (26 ) (299 ) (189 ) (512 ) Ending balance $ 8,531 $ 4,891 $ 8,531 $ 4,891

Goodwill, Core Deposit Intang_2

Goodwill, Core Deposit Intangible and Other Intangible Assets (Tables)	9 Months Ended
	Sep. 30, 2019
Goodwill And Intangible Assets Disclosure [Abstract]
Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets	The following tables summarize the changes in the Company’s goodwill, core deposit intangible assets, and customer relationship intangible assets for the three and nine months ended September 30, 2019 and 2018: Nine Months Ended September 30, 2019 2018 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 128,177 $ 30,360 $ 3,059 $ 54,562 $ 16,720 $ — Additions 17,461 6,220 — 72,974 19,060 3,216 Amortization — (5,534 ) (200 ) — (3,685 ) (89 ) Ending balance $ 145,638 $ 31,046 $ 2,859 $ 127,536 $ 32,095 $ 3,127 Accumulated amortization N/A $ 24,420 $ 358 N/A $ 17,151 89 Weighted average remaining amortization period N/A 6.7 Years 10.7 Years N/A 7.1 Years 11.7 Years Three Months Ended September 30, 2019 2018 Goodwill Core Intangible Customer Relationship Intangible Goodwill Core Intangible Customer Relationship Intangible Beginning balance $ 145,638 $ 32,982 $ 2,926 $ 127,536 $ 33,917 $ 3,194 Additions — — — — — — Amortization — (1,936 ) (67 ) — (1,822 ) (67 ) Ending balance $ 145,638 $ 31,046 $ 2,859 $ 127,536 $ 32,095 $ 3,127 Accumulated amortization N/A $ 24,420 $ 358 N/A $ 17,151 89 Weighted average remaining amortization period N/A 6.7 Years 10.7 Years N/A 7.1 Years 11.7 Years
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, 2019: Estimated Amortization 2019 $ 2,002 2020 7,577 2021 7,012 2022 6,440 2023 4,336 Thereafter 6,538 Total $ 33,905

Deposits (Tables)

Deposits (Tables)	9 Months Ended
	Sep. 30, 2019
Deposits [Abstract]
Composition of Deposits	The composition of deposits was as follows as of September 30, 2019 and December 31, 2018: September 30, December 31, 2019 2018 Non-interest-bearing demand deposits $ 1,221,431 $ 1,192,873 Interest-bearing checking accounts 372,049 296,339 Money market demand accounts 745,154 640,401 Other savings 471,878 476,418 Time deposits (below $250,000) 966,866 911,603 Time deposits ($250,000 and above) 302,936 232,282 Total deposits $ 4,080,314 $ 3,749,916

Federal Home Loan Bank Advanc_2

Federal Home Loan Bank Advances (Tables)	9 Months Ended
	Sep. 30, 2019
Federal Home Loan Banks [Abstract]
Summary of FHLB Advances	The following September 30, December 31, 2019 2018 Federal Home Loan Bank advances $ 506,000 $ 425,000 Weighted average cost 2.05 % 2.56 %

Other Borrowings (Tables)

Other Borrowings (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Summary of Other Borrowings	The following is a summary of the Company’s other borrowings as of September 30, 2019 and December 31, 2018: September 30, December 31, 2019 2018 Securities sold under agreements to repurchase $ 32,290 $ 34,166 Line of credit — — Total $ 32,290 $ 34,166
Summary of Short-term Credit Lines Available for Use	The following September 30, December 31, 2019 2018 Federal Reserve Bank of Chicago discount window line $ 419,086 $ 293,613 Available federal funds lines 105,000 55,000

Junior Subordinated Debentures

Junior Subordinated Debentures (Tables)	9 Months Ended
	Sep. 30, 2019
Debt Disclosure [Abstract]
Junior Subordinated Debentures by Issuance	At September 30, 2019 and December 31, 2018, the Name of Trust Aggregate Principal Amount September 30, 2019 Aggregate Principal Amount December 31, 2018 Stated Maturity Contractual Rate at September 30, 2019 Interest Rate Spread Metropolitan $ 35,000 $ 35,000 March 4.93 % Three-month LIBOR + 2.79% RidgeStone Capital Trust I 1,500 1,500 June 30, 2033 6.38 % Five-year LIBOR + 3.50% First Evanston Bancorp Trust I 10,000 10,000 March 15, 2035 3.90 % Three-month LIBOR + 1.78% Total liability, at par 46,500 46,500 Discount (9,293 ) (9,732 ) Total liability, at carrying value $ 37,207 $ 36,768

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Tables)	9 Months Ended
	Sep. 30, 2019
Commitments And Contingencies Disclosure [Abstract]
Summary of Minimum Annual Rental Commitments for Operating Leases	The minimum Minimum Commitments 2019 $ 1,166 2020 4,455 2021 3,798 2022 2,230 2023 1,294 Thereafter 3,303 Total $ 16,246
Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments	The following September 30, 2019 December 31, 2018 Fixed Rate Variable Total Fixed Variable Total Commitments to extend credit $ 51,101 $ 930,778 $ 981,879 $ 74,099 $ 928,991 $ 1,003,090 Letters of credit 784 39,724 40,508 1,982 34,071 36,053 Total $ 51,885 $ 970,502 $ 1,022,387 $ 76,081 $ 963,062 $ 1,039,143

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Summary of Company's Financial Assets and Liabilities Measured at Fair Value on Recurring Basis	The following Fair Value Measurements Using September 30, 2019 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 42,842 $ 42,842 $ — $ — U.S. Government agencies 177,858 — 177,858 — Obligations of states, municipalities, and political subdivisions 98,602 — 98,407 195 Mortgage-backed securities; residential Agency 329,010 — 329,010 — Non-Agency 120,060 — 120,060 — Mortgage-backed securities; commercial Agency 152,033 — 152,033 — Non-Agency 31,500 — 31,500 — Corporate securities 47,194 — 47,194 — Other securities 32,834 — 32,834 — Equity and other securities, at fair value Mutual funds 2,944 2,944 — — Equity securities 4,704 — 4,008 696 Servicing assets 19,939 — — 19,939 Derivative assets 10,288 — 10,288 — Financial liabilities Derivative liabilities 11,093 — 11,093 — Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Financial assets Securities available-for-sale U.S. Treasury Notes $ 52,667 $ 52,667 $ — $ — U.S. Government agencies 186,498 — 186,498 — Obligations of states, municipalities, and political subdivisions 60,233 — 60,038 195 Mortgage-backed securities; residential Agency 272,963 — 272,963 — Non-Agency 83,621 — 83,621 — Mortgage-backed securities; commercial Agency 90,434 — 90,434 — Non-Agency 30,458 — 30,458 — Corporate securities 34,173 — 34,173 — Other securities 6,609 2,844 3,074 691 Servicing assets 19,693 — — 19,693 Derivative assets 10,740 — 10,740 — Financial liabilities Derivative liabilities 4,243 — 4,243 —
Summary of Financial Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs	The following table presents additional information about financial assets measured at fair value on recurring basis for which the Company used significant unobservable inputs (Level 3): Nine Months Ended September 30, 2019 2018 2019 2018 Investment Securities Servicing Assets Balance, beginning of period $ 886 $ 1,052 $ 19,693 $ 21,400 Acquired assets at fair value — 314 — — Additions, net — — 4,340 5,680 Amortization 4 4 — — Change in unrealized gain 1 11 — — Change in fair value — — (4,094 ) (6,406 ) Balance, end of period $ 891 $ 1,381 $ 19,939 $ 20,674
Summary of Unobservable Inputs Used in the Fair Value Measurements on Recurring Basis	The following Financial Instruments Valuation Technique Unobservable Inputs Range of Inputs Weighted Average Range Impact to Valuation from an Increased or Higher Input Value Obligations of states, municipalities, and political obligations Discounted Probability of default 2.4% 2.4% Decrease Single issuer trust preferred Discounted cash flow Probability of default 4.9%—5.4% 5.8% Decrease Servicing assets Discounted cash flow Prepayment speeds 2.7%—21.9% 13.7% Decrease Discount rate 4.8%—24.0% 12.2% Decrease Expected weighted average loan life 0.1—9.5 years 4.5 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, 2019 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 21,343 $ — $ — $ 21,343 Residential real estate 2,335 — — 2,335 Commercial and industrial 19,936 — — 19,936 Assets held for sale 15,472 — — 15,472 Other real estate owned 8,531 — — 8,531 Fair Value Measurements Using December 31, 2018 Fair Value Level 1 Level 2 Level 3 Non-recurring Impaired loans (excluding acquired impaired loans) Commercial real estate $ 9,792 $ — $ — $ 9,792 Residential real estate 2,076 — — 2,076 Commercial and industrial 17,397 — — 17,397 Assets held for sale 14,489 — — 14,489 Other real estate owned 5,314 — — 5,314
Estimated Fair Values of Financial Instruments	The estimated not carried at fair value September 30, December 31, Fair Value 2019 2018 Hierarchy Level Carrying Amount Estimated Fair Value Carrying Amount Estimated Fair Value Financial assets Cash and due from banks 1 $ 75,275 $ 75,275 $ 30,190 $ 30,190 Interest bearing deposits with other banks 2 33,564 33,564 91,670 91,670 Securities held-to-maturity 2 4,417 4,503 99,266 97,739 Other restricted stock 2 24,331 24,331 19,202 19,202 Loans held for sale 3 7,176 7,922 19,827 21,654 Loans and lease receivables, net (less impaired loans at fair value (1) 3 3,755,891 3,677,608 3,447,160 3,407,652 Accrued interest receivable 3 13,013 13,013 10,863 10,863 Financial liabilities Non-interest-bearing deposits 2 1,221,431 1,221,431 1,192,873 1,192,873 Interest-bearing deposits 2 2,858,883 2,867,646 2,557,043 2,554,329 Accrued interest payable 2 4,778 4,778 3,484 3,484 Line of credit 2 — — — — Federal Home Loan Bank advances 2 506,000 506,000 425,000 425,000 Securities sold under repurchase agreement 2 32,290 32,290 34,166 34,166 Junior subordinated debentures 3 37,207 42,496 36,768 42,351 (1) In accordance with the prospective adoption of ASU 2016-01, the fair value of loans and lease receivables, net (less impaired loans at fair value) as of September 30, 2019 was measured using an exit price notion. The fair value as of December 31, 2018 was measured using an entry price notion.

Derivative Instruments and He_2

Derivative Instruments and Hedge Activities (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments And Hedging Activities Disclosure [Abstract]
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, 2019 and December 31, 2018: September 30, 2019 December 31, 2018 Fair Value Fair Value Notional Amount Other Assets Other Liabilities Notional Amount Other Assets Other Liabilities Derivatives designated as hedging instruments Interest rate swaps designated as cash flow hedges $ — $ — $ — $ 250,000 $ 6,699 $ — Derivatives not designated as hedging instruments Other interest rate derivatives 296,656 10,288 11,076 294,545 4,041 4,237 Other credit derivatives 9,519 — 17 4,424 — 6 Total derivatives $ 306,175 $ 10,288 $ 11,093 $ 548,969 $ 10,740 $ 4,243
Summary of Net Gains (Losses) Recorded in Accumulated Other Comprehensive Income (Loss) and Consolidated Statements of Operations Relating to Cash Flow Derivative Instruments	The following table reflects the net gains (losses) recorded in accumulated other comprehensive income (loss) and the Consolidated Statements of Operations relating to the cash flow derivative instruments for the nine months ended: September 30, 2019 September 30, 2018 Amount of Loss Recognized in OCI Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Amount of Gain Recognized in OCI Amount of Gain Reclassified from OCI to Income as an Increase to Interest Expense Amount of Gain (Loss) Recognized in Other Non-Interest Income Interest rate swaps $ (5,484 ) $ 1,643 $ — $ 6,702 $ 863 $ —
Summary of Other Interest Rate Derivatives	The following table reflects other interest rate derivatives as of September 30, 2019 Notional amounts $ 296,656 Derivative assets fair value 10,288 Derivative liabilities fair value 11,076 Weighted average pay rates 4.74 % Weighted average receive rates 4.37 % Weighted average maturity 6.8 years
Summary of Company's Interest Rate Derivative and Offsetting Positions	The 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, 2019 December 31, 2018 Derivative Assets Fair Value Derivative Liabilities Fair Value Derivative Assets Fair Value Derivative Liabilities Fair Value Gross amounts recognized $ 10,288 $ 11,093 $ 10,740 $ 4,243 Less: Amounts offset in the Consolidated Statements of Financial Condition — — — — Net amount presented in the Consolidated Statements of Financial Condition $ 10,288 $ 11,093 $ 10,740 $ 4,243 Gross amounts not offset in the Consolidated Statements of Financial Condition Offsetting derivative positions (1 ) (1 ) (2,823 ) (2,823 ) Collateral posted (10,287 ) (11,092 ) (7,917 ) (1,317 ) Net credit exposure $ — $ — $ — $ 103

Share-Based Compensation (Table

Share-Based Compensation (Tables)	9 Months Ended
	Sep. 30, 2019
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Summary of Stock Compensation Expense	The following table summarizes stock option compensation expense for the nine months ended September 30, 2019 and 2018: Nine Months Ended September 30, 2019 2018 Total share-based compensation (benefit) - stock options $ (119 ) $ 510 Income tax benefit (expense) (33 ) 142 Unrecognized compensation expense - stock options 21 209 Weighted-average amortization period remaining 0.5 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, 2019 and 2018: Nine Months Ended September 30, 2019 2018 Total share-based compensation - restricted stock $ 1,357 $ 638 Income tax benefit 378 178 Unrecognized compensation expense 4,917 3,379 Weighted-average amortization period remaining 2.8 years 3.1 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, 2019: Omnibus Plan Number of Shares Weighted Average Grant Date Fair Value Beginning balance, January 1, 2019 196,480 $ 21.66 Granted 192,199 18.70 Vested (37,310 ) 22.01 Forfeited (27,880 ) 19.75 Ending balance outstanding at September 30, 2019 323,489 $ 20.03
BYB 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 and the weighted average exercise prices, in actual dollars, for the nine months ended September 30, 2019: BYB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 1,598,872 $ 11.84 $ 7,713 6.6 Exercised (89,000 ) 16.25 $ 253 Forfeited (60,800 ) 16.25 Ending balance outstanding at September 30, 2019 1,449,072 $ 11.38 $ 9,420 5.6 Exercisable at September 30, 2019 1,411,572 $ 11.25 $ 9,359 5.6
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, 2019: FEB Plan Number of Shares Weighted Average Exercise Price Intrinsic Value Weighted Average Remaining Contractual Term (in Years) Beginning balance, January 1, 2019 624,383 $ 11.31 $ 3,339 5.2 Granted — Expired — Exercised (81,182 ) 11.24 $ 677 Forfeited — Ending balance outstanding at September 30, 2019 543,201 $ 11.32 $ 3,561 4.5 Exercisable at September 30, 2019 543,201 $ 11.32 $ 3,561 4.5

Earnings per Share (Tables)

Earnings per Share (Tables)	9 Months Ended
	Sep. 30, 2019
Earnings Per Share [Abstract]
Schedule of Calculation of Basic and Diluted Earnings per Share	The following represent the calculation of basic and diluted earnings per share for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, 2019 2018 2019 2018 Net income $ 15,342 $ 14,536 $ 41,150 $ 24,072 Less: Dividends on preferred shares 196 196 587 587 Net income available to common stockholders $ 15,146 $ 14,340 $ 40,563 $ 23,485 Weighted-average common stock outstanding: Weighted-average common stock outstanding (basic) 37,831,356 36,042,914 37,094,083 32,341,087 Incremental shares 655,824 915,295 724,785 947,570 Weighted-average common stock outstanding (dilutive) 38,487,180 36,958,209 37,818,868 33,288,657 Basic earnings per common share $ 0.40 $ 0.40 $ 1.09 $ 0.73 Diluted earnings per common share $ 0.39 $ 0.39 $ 1.07 $ 0.71

Stockholders' Equity (Tables)

Stockholders' Equity (Tables)	9 Months Ended
	Sep. 30, 2019
Equity [Abstract]
Summary of Preferred and Common Stock	A summary of the Company’s preferred and common stock at September 30, 2019 and December 31, 2018 is as follows: September 30, December 31, 2019 2018 Series B 7.5% fixed to floating non-cumulative perpetual preferred stock Par value $ 0.01 $ 0.01 Shares authorized 50,000 50,000 Shares issued 10,438 10,438 Shares outstanding 10,438 10,438 Common stock, voting Par value $ 0.01 $ 0.01 Shares authorized 150,000,000 150,000,000 Shares issued 38,169,126 36,343,239 Shares outstanding 38,169,126 36,343,239

Consolidated Statements of Ch_3

Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Tables)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income Loss Net Of Tax [Abstract]
Schedule of Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss)	The following table summarizes the changes in accumulated other comprehensive income (loss) for the nine months ended September 30, 2019 and 2018: (dollars in thousands) Unrealized Gains (Losses) on Cash Flow Hedges Unrealized (Losses) on Available-for -Sale Securities Total Accumulated Other Comprehensive Income (Loss) Balance, January 1, 2018 $ 2,913 $ (8,000 ) $ (5,087 ) Reclassification of certain income tax effects from accumulated other comprehensive income 687 (1,450 ) (763 ) Other comprehensive income (loss), net of tax 4,213 (10,725 ) (6,512 ) Balance, September 30, 2018 $ 7,813 $ (20,175 ) $ (12,362 ) Balance, January 1, 2019 $ 4,763 $ (14,261 ) $ (9,498 ) Cumulative-effect adjustment (ASU 2016-01) — (1,440 ) (1,440 ) Other comprehensive income (loss), net of tax (5,142 ) 17,041 11,899 Balance, September 30, 2019 $ (379 ) $ 1,340 $ 961

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details)	9 Months Ended
	Sep. 30, 2019segment
Organization Consolidation And Presentation Of Financial Statements [Abstract]
Number of reportable segments	1

Accounting Pronouncements Rec_3

Accounting Pronouncements Recently Adopted or Issued - Additional Information (Details) - USD ($)	Jan. 01, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification from other comprehensive income to retained earnings				$ (1,440,000)
Equity and other securities, at fair value		$ 7,648,000		7,648,000
ASU 2014-09
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Change in ATM and interchange fees		$ 396,000	$ 241,000	$ 1,100,000	$ 837,000
ASU 2016-01
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification from other comprehensive income to retained earnings	$ 1,400,000
Equity and other securities, at fair value						$ 6,600,000
ASU 2017-12
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Reclassification of securities held-to-maturity to securities available-for-sale	$ 94,800,000

Accounting Pronouncements Rec_4

Accounting Pronouncements Recently Adopted or Issued - Impact of Adopting the New Revenue Standard on Consolidated Statements of Operations (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Non-interest income:
ATM and interchange fees	$ 973	$ 1,540	$ 2,635	$ 3,303
Non-interest expense:
Other non-interest expense	2,679	2,880	8,358	6,769
Balance without Adoption of ASC 606 | ASU 2014-09
Non-interest income:
ATM and interchange fees	1,369	1,781	3,757	4,140
Non-interest expense:
Other non-interest expense	3,075	3,121	9,480	7,606
Effect of Change | ASU 2014-09
Non-interest income:
ATM and interchange fees	(396)	(241)	(1,122)	(837)
Non-interest expense:
Other non-interest expense	$ (396)	$ (241)	$ (1,122)	$ (837)

Acquisitions - Additional Infor

Acquisitions - Additional Information (Details) - USD ($)	May 15, 2019	Apr. 30, 2019	May 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill				$ 145,638,000	$ 127,536,000	$ 145,638,000	$ 127,536,000	$ 145,638,000	$ 128,177,000	$ 127,536,000	$ 54,562,000
Oak Park River Forest Bankshares, Inc.
Business Acquisition [Line Items]
Business acquisition date of agreement						Apr. 30, 2019
Right to receive common stock upon conversion		7.9321
Consideration paid in cash	$ 4,200,000	$ 6,163,000
Common stock outstanding value per share		$ 33.375
Common stock issued price per share		$ 20.02
Issuance of common shares		1,464,558
Value of common stock consideration		$ 29,300,000
Options to acquire common stock shares		35,870
Option to acquire common stock value		$ 4,200,000
Total merger consideration		35,483,000
Stock issuance costs		429,000
Goodwill		$ 17,461,000
Oak Park River Forest Bankshares, Inc. | Non-interest Expense
Business Acquisition [Line Items]
Acquisition advisory expenses						$ 2,300,000
Merger related income from legal fee credit				135,000
Core system conversion expenses				1,200,000		$ 1,900,000
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
Option to acquire common stock value			$ 7,600,000
Total merger consideration			179,131,000
Stock issuance costs			852,000
Goodwill			$ 73,615,000
Options to acquire conversion of common stock shares			680,787
First Evanston Bancorp, Inc. | Non-interest Expense
Business Acquisition [Line Items]
Acquisition advisory expenses				0	50,000	$ 0	1,700,000
Core system conversion expenses				$ 76,000	$ 213,000	$ 2,000,000	$ 9,200,000

Acquisitions - Summary of Fair

Acquisitions - Summary of Fair Values of Assets and Liabilities Assumed as of Acquisition Dates (Details) - USD ($) $ in Thousands	May 15, 2019	Apr. 30, 2019	May 31, 2018	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Consideration paid
Goodwill				$ 145,638	$ 145,638	$ 128,177	$ 127,536	$ 127,536	$ 54,562
Oak Park River Forest Bankshares, Inc.
Assets
Cash and cash equivalents		$ 10,469
Securities available-for-sale		30,343
Restricted stock		414
Loans		261,151
Premises and equipment		3,488
Other real estate owned		2,201
Other intangible assets		6,220
Bank-owned life insurance		3,485
Deferred tax assets, net		4,887
Other assets		1,256
Total assets acquired		323,914
Liabilities
Deposits		290,171
Line of credit		5,655
Federal Home Loan Bank advances		5,300
Accrued expenses and other liabilities		4,766
Total liabilities assumed		305,892
Net assets acquired		18,022
Consideration paid
Common stock (2019 - 1,464,558 shares issued at $20.02 per share, 2018 - 6,682,850 shares issued at $21.62 per share)		29,320
Consideration paid in cash	$ 4,200	6,163
Total consideration paid		35,483
Goodwill		$ 17,461
First Evanston Bancorp, Inc.
Assets
Cash and cash equivalents			$ 47,378
Securities available-for-sale			128,063
Restricted stock			1,360
Loans			916,011
Premises and equipment			15,890
Other intangible assets			22,276
Deferred tax assets, net			2,302
Other assets			8,845
Total assets acquired			1,142,125
Liabilities
Deposits			1,022,268
Junior subordinated debentures			8,497
Accrued expenses and other liabilities			5,844
Total liabilities assumed			1,036,609
Net assets acquired			105,516
Consideration paid
Common stock (2019 - 1,464,558 shares issued at $20.02 per share, 2018 - 6,682,850 shares issued at $21.62 per share)			144,483
Outstanding stock options converted to Byline stock options			7,644
Consideration paid in cash			27,004
Total consideration paid			179,131
Goodwill			$ 73,615

Acquisitions - Summary of Fai_2

Acquisitions - Summary of Fair Values of Assets and Liabilities Assumed as of Acquisition Dates (Parenthetical) (Details) - $ / shares	Apr. 30, 2019	May 31, 2018
Oak Park River Forest Bankshares, Inc.
Business Acquisition [Line Items]
Stock issued (in shares)	1,464,558
Stock issued (in dollars per share)	$ 20.02
First Evanston Bancorp, Inc.
Business Acquisition [Line Items]
Stock issued (in shares)		6,682,850
Stock issued (in dollars per share)		$ 21.62

Acquisitions - Summary of Acqui

Acquisitions - Summary of Acquired Non-Impaired Loans as of Acquisition Dates (Details) - USD ($) $ in Thousands		Apr. 30, 2019	May 31, 2018
Oak Park River Forest Bankshares, Inc.
Business Acquisition [Line Items]
Fair value		$ 212,587
Gross contractual amounts receivable		275,553
Estimate of contractual cash flows not expected to be collected	[1]	23,932
Estimate of contractual cash flows expected to be collected		$ 251,621
First Evanston Bancorp, Inc.
Business Acquisition [Line Items]
Fair value			$ 890,986
Gross contractual amounts receivable			1,057,374
Estimate of contractual cash flows not expected to be collected	[1]		36,544
Estimate of contractual cash flows expected to be collected			$ 1,020,830
[1]	Includes interest payments not expected to be collected due to loan prepayments as well as principal and interest payments not expected to be collected due to customer default.

Acquisitions - Summary of Unaud

Acquisitions - 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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Business Combinations [Abstract]
Total revenues (net interest income and non-interest income)	$ 72,644	$ 69,019	$ 209,765	$ 200,371
Net income	$ 15,342	$ 15,673	$ 45,138	$ 42,160
Earnings per share—basic	$ 0.40	$ 0.41	$ 1.18	$ 1.11
Earnings per share—diluted	$ 0.39	$ 0.40	$ 1.16	$ 1.08

Securities - Summary of Amortiz

Securities - Summary of Amortized Cost and Fair Values of Securities Available-for-sale (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	$ 1,026,724	$ 834,254
Available-for-sale Securities, Gross Unrealized Gains	8,989	3,130
Available-for-sale Securities, Gross Unrealized Losses	(3,780)	(19,728)
Available-for-sale Securities, Fair Value	1,031,933	817,656
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	42,381	52,775
Available-for-sale Securities, Gross Unrealized Gains	461	81
Available-for-sale Securities, Gross Unrealized Losses		(189)
Available-for-sale Securities, Fair Value	42,842	52,667
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	177,082	187,427
Available-for-sale Securities, Gross Unrealized Gains	1,048	367
Available-for-sale Securities, Gross Unrealized Losses	(272)	(1,296)
Available-for-sale Securities, Fair Value	177,858	186,498
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	96,564	60,686
Available-for-sale Securities, Gross Unrealized Gains	2,269	133
Available-for-sale Securities, Gross Unrealized Losses	(231)	(586)
Available-for-sale Securities, Fair Value	98,602	60,233
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	329,145	284,038
Available-for-sale Securities, Gross Unrealized Gains	2,178	101
Available-for-sale Securities, Gross Unrealized Losses	(2,313)	(11,176)
Available-for-sale Securities, Fair Value	329,010	272,963
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	119,661	84,998
Available-for-sale Securities, Gross Unrealized Gains	644	199
Available-for-sale Securities, Gross Unrealized Losses	(245)	(1,576)
Available-for-sale Securities, Fair Value	120,060	83,621
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	150,891	93,543
Available-for-sale Securities, Gross Unrealized Gains	1,698	55
Available-for-sale Securities, Gross Unrealized Losses	(556)	(3,164)
Available-for-sale Securities, Fair Value	152,033	90,434
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	31,224	31,458
Available-for-sale Securities, Gross Unrealized Gains	276
Available-for-sale Securities, Gross Unrealized Losses		(1,000)
Available-for-sale Securities, Fair Value	31,500	30,458
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	46,821	34,716
Available-for-sale Securities, Gross Unrealized Gains	415	67
Available-for-sale Securities, Gross Unrealized Losses	(42)	(610)
Available-for-sale Securities, Fair Value	47,194	34,173
Other Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Amortized Cost	32,955	4,613
Available-for-sale Securities, Gross Unrealized Gains		2,127
Available-for-sale Securities, Gross Unrealized Losses	(121)	(131)
Available-for-sale Securities, Fair Value	$ 32,834	$ 6,609

Securities - Summary of Amort_2

Securities - Summary of Amortized Cost and Fair Values of Securities Held-to-maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	$ 4,417	$ 99,266
Held-to-maturity Securities, Gross Unrealized Gains	85	133
Held-to-maturity Securities, Gross Unrealized Losses		(1,660)
Held-to-maturity Securities, Fair Value	4,502	97,739
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost	4,417	23,835
Held-to-maturity Securities, Gross Unrealized Gains	85	40
Held-to-maturity Securities, Gross Unrealized Losses		(210)
Held-to-maturity Securities, Fair Value	$ 4,502	23,665
Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost		40,082
Held-to-maturity Securities, Gross Unrealized Gains		93
Held-to-maturity Securities, Gross Unrealized Losses		(531)
Held-to-maturity Securities, Fair Value		39,644
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Held To Maturity Securities [Line Items]
Held-to-maturity Securities, Amortized Cost		35,349
Held-to-maturity Securities, Gross Unrealized Losses		(919)
Held-to-maturity Securities, Fair Value		$ 34,430

Securities - Additional Informa

Securities - Additional Information (Details)	Jan. 01, 2019USD ($)	Sep. 30, 2019USD ($)Security	Sep. 30, 2018USD ($)	Sep. 30, 2019USD ($)Security	Sep. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Schedule Of Investments [Line Items]
Trading securities		$ 0		$ 0		$ 0
Reclassification from other comprehensive income to retained earnings				(1,440,000)
Equity and other securities, at fair value		7,648,000		7,648,000
Net gains or (losses) reclassified from accumulated other comprehensive income (loss) into earnings		178,000	$ 0	1,200,000	$ 4,000
Carrying amount of securities pledged as collateral		$ 306,900,000		$ 306,900,000		$ 244,700,000
Minimum
Schedule Of Investments [Line Items]
Percentage of shareholders equity for which securities holdings exceeds for no issuer other than U.S. Government and agencies		10.00%		10.00%		10.00%
Federal Home Loan Bank Advances
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral		$ 0		$ 0		$ 0
Public Fund Deposits
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral		263,300,000		263,300,000		197,800,000
Customer Repurchase Agreements
Schedule Of Investments [Line Items]
Carrying amount of securities pledged as collateral		$ 43,600,000		$ 43,600,000		46,900,000
Available-for-sale Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security		74		74
Held-to-maturity Securities
Schedule Of Investments [Line Items]
Investment securities with unrealized losses | Security		0		0
ASU 2016-01
Schedule Of Investments [Line Items]
Reclassification from other comprehensive income to retained earnings	$ 1,400,000
Equity and other securities, at fair value						$ 6,600,000
ASU 2017-12
Schedule Of Investments [Line Items]
Reclassification of securities held-to-maturity to securities available-for-sale	$ 94,800,000

Securities - Summary of Gross U

Securities - Summary of Gross Unrealized Losses and Fair Values, Aggregated by Investment Category and Length of Individual Securities Continuous Unrealized Loss Position Available-for-sale (Details) $ in Thousands	Sep. 30, 2019USD ($)Security	Dec. 31, 2018USD ($)Security
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	74	179
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 174,737	$ 191,761
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(1,049)	(2,441)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	288,243	427,243
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(2,731)	(17,287)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	462,980	619,004
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (3,780)	$ (19,728)
U.S. Treasury Notes
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security		18
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value		$ 23,835
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses		(52)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		9,865
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(137)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value		33,700
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses		$ (189)
U.S. Government Agencies
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	5	25
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 14,834	$ 43,487
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(163)	(80)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	20,266	50,101
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(109)	(1,216)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	35,100	93,588
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (272)	$ (1,296)
Obligations of States, Municipalities, and Political Subdivisions
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	4	56
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 9,960	$ 13,926
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(226)	(97)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	1,417	18,563
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(5)	(489)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	11,377	32,489
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (231)	$ (586)
Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	40	42
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 32,436	$ 4,288
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(179)	(45)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	204,649	254,121
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(2,134)	(11,131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	237,085	258,409
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (2,313)	$ (11,176)
Non-Agency, Residential Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	11	8
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 36,826	$ 59,107
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(62)	(1,378)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	28,142	4,009
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(183)	(198)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	64,968	63,116
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (245)	$ (1,576)
Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	8	9
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 38,571	$ 21,356
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(256)	(447)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value	33,769	52,640
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses	(300)	(2,717)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	72,340	73,996
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (556)	$ (3,164)
Non-Agency, Commercial Mortgage-Backed Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security		5
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		$ 30,458
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(1,000)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value		30,458
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses		$ (1,000)
Corporate Securities
Schedule Of Available For Sale Securities [Line Items]
Available-for-sale Securities, Continuous Unrealized Loss Position, Number of Securities | Security	5	15
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Fair Value	$ 9,276	$ 25,762
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(42)	(342)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		4,642
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(268)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	9,276	30,404
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (42)	$ (610)
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, Less than 12 Months, Fair Value	$ 32,834
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Unrealized Losses	(121)
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Fair Value		$ 2,844
Available-for-sale Securities, Continuous Unrealized Loss Position, 12 Months or Longer, Unrealized Losses		(131)
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Fair Value	32,834	2,844
Available-for-sale Securities, Continuous Unrealized Loss Position, Total Unrealized Losses	$ (121)	$ (131)

Securities - Summary of Gross_2

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

Securities - Summary of Proceed

Securities - Summary of Proceeds From Sales of Securities Available-for-sale and Associated Gains and Losses (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018
Available For Sale Securities Gross Realized Gain Loss [Abstract]
Proceeds	$ 32,509	$ 92,103	$ 544
Gross gains	225	1,274	$ 4
Gross losses	$ 47	$ 123

Securities - Schedule of Amorti

Securities - Schedule of Amortized Cost and Fair Value of Debt Securities by Contractual Maturity (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Equity and Other Securities, Amortized Cost [Abstract]
Equity and Other Securities, Due after ten years, Amortized Cost	$ 697
Equity and Other Securities, Not due at single maturity, Amortized Cost	6,951
Equity and Other Securities, Amortized Cost	7,648
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Due in one year or less, Amortized Cost	59,697
Available-for-sale Securities, Due from one to five years, Amortized Cost	123,941
Available-for-sale Securities, Due from five to ten years, Amortized Cost	136,438
Available-for-sale Securities, Due after ten years, Amortized Cost	75,727
Available-for-sale Securities, Amortized Cost	1,026,724	$ 834,254
Held-to-maturity Securities Debt Maturities, Amortized Cost [Abstract]
Held-to-maturity Securities, Due from one to five years, Amortized Cost	3,805
Held-to-maturity Securities, Due from five to ten years, Amortized Cost	612
Held-to-maturity Securities, Amortized Cost	4,417	99,266
Equity and Other Securities, Fair Value [Abstract]
Equity and Other Securities, Due after ten years, Fair Value	697
Equity and Other Securities, Not due at single maturity, Fair Value	6,951
Equity and Other Securities, Fair Value	7,648
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Due in one year or less, Fair Value	59,875
Available-for-sale Securities, Due from one to five years, Fair Value	125,158
Available-for-sale Securities, Due from five to ten years, Fair Value	137,993
Available-for-sale Securities, Due after ten years, Fair Value	76,304
Available-for-sale Securities, Fair Value, Total	1,031,933	817,656
Held-to-maturity Securities Debt Maturities, Fair Value [Abstract]
Held-to-maturity Securities, Due from one to five years, Fair Value	3,873
Held-to-maturity Securities, Due from five to ten years, Fair Value	629
Held-to-maturity securities, Fair Value, Total	4,502	$ 97,739
Mortgage-Backed Securities
Available-for-sale Securities Debt Maturities, Amortized Cost [Abstract]
Available-for-sale Securities, Not due at single maturity, Amortized Cost	630,921
Available-for-sale Securities Debt Maturities, Fair Value [Abstract]
Available-for-sale Securities, Not due at single maturity, Fair Value	$ 632,603

Loan and Lease Receivables - Sc

Loan and Lease Receivables - Schedule of Outstanding Loan and Lease Receivables (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,826,735		$ 3,499,463
Net unamortized deferred fees and costs	1,444		(1,293)
Initial direct costs	2,911		3,456
Allowance for loan and lease losses	(31,585)	$ (31,132)	(25,201)	$ (23,424)	$ (19,687)	$ (16,706)
Net loans and leases	3,799,505		3,476,425
Lease financing receivables
Net minimum lease payments	196,163		204,646
Unguaranteed residual values	1,379		1,535
Unearned income	(17,269)		(18,384)
Total lease financing receivables	180,273		187,797
Initial direct costs	2,911		3,456
Lease financial receivables before allowance for lease losses	183,184		191,253
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,305,438		1,261,594
Allowance for loan and lease losses	(8,553)	(8,934)	(7,540)	(7,422)	(6,453)	(4,794)
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	748,875		704,899
Allowance for loan and lease losses	(2,251)	(2,171)	(1,751)	(1,677)	(1,648)	(1,638)
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	281,868		186,258
Allowance for loan and lease losses	(816)	(691)	(466)	(390)	(332)	(222)
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,300,997		1,145,240
Allowance for loan and lease losses	(17,783)	(17,126)	(12,932)	(11,165)	(8,369)	(7,418)
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	9,284		13,675
Allowance for loan and lease losses	(55)	(67)	(49)	(38)	(30)	(41)
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	180,273		187,797
Allowance for loan and lease losses	$ (2,127)	$ (2,143)	$ (2,463)	$ (2,732)	$ (2,855)	$ (2,593)

Loan and Lease Receivables - Ad

Loan and Lease Receivables - Additional Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Apr. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	May 31, 2018	Dec. 31, 2017
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,826,735			$ 3,499,463
Loans held for sale pledged as security for borrowings	1,900,000			1,400,000
Allowance for loan and lease losses	31,585	$ 31,132		25,201	$ 23,424	$ 19,687		$ 16,706
Acquired Impaired Loans
Accounts Notes And Loans Receivable [Line Items]
Allowance for loan and lease losses	2,800			2,700
Acquired Impaired Loans | First Evanston Bancorp, Inc.
Accounts Notes And Loans Receivable [Line Items]
Loans acquired							$ 25,025
Acquired Impaired Loans | Oak Park River Forest Bankshares, Inc.
Accounts Notes And Loans Receivable [Line Items]
Loans acquired			$ 48,564
Acquired Non-Impaired Loans and Leases | Oak Park River Forest Bankshares, Inc.
Accounts Notes And Loans Receivable [Line Items]
Loans acquired	212,600
Acquired Non-Impaired Loans and Leases | First Evanston
Accounts Notes And Loans Receivable [Line Items]
Loans acquired	891,000
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	9,284			13,675
Overdraft deposits reclassified as loans	2,000			1,700
Allowance for loan and lease losses	55	$ 67		49	$ 38	$ 30		$ 41
U.S. Government Guaranteed Loans
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 139,800			$ 108,700

Loan and Lease Receivables - Su

Loan and Lease Receivables - Summary of Minimum Annual Lease Payments for Lease Financing Receivables (Details) $ in Thousands	Sep. 30, 2019USD ($)
Receivables [Abstract]
2019	$ 18,025
2020	70,292
2021	51,235
2022	33,733
2023	17,614
Thereafter	5,264
Total	$ 196,163

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, 2019	Dec. 31, 2018	Sep. 30, 2018
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 3,831,090	$ 3,501,626	$ 3,455,802
Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	2,771,457	2,237,798
Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	275,022	277,542
Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	784,611	986,286
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,306,288	1,261,607	1,272,204
Commercial Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	772,559	652,234
Commercial Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	142,435	146,808
Commercial Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	391,294	462,565
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	749,103	704,902	705,196
Residential Real Estate | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	497,839	466,309
Residential Real Estate | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	109,409	113,934
Residential Real Estate | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	141,855	124,659
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	280,999	185,349	181,705
Construction, Land Development, and Other Land | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	236,780	144,128
Construction, Land Development, and Other Land | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	4,562	3,779
Construction, Land Development, and Other Land | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	39,657	37,442
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,302,162	1,144,797	1,095,446
Commercial and Industrial | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,096,400	803,508
Commercial and Industrial | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	18,349	12,617
Commercial and Industrial | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	187,413	328,672
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	9,354	13,718	12,194
Installment and Other | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	7,818	11,718
Installment and Other | Acquired Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	267	404
Installment and Other | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	1,269	1,596
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	183,184	191,253	$ 189,057
Lease Financing Receivables | Originated
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	160,061	159,901
Lease Financing Receivables | Acquired Non-Impaired
Accounts Notes And Loans Receivable [Line Items]
Total loans and leases	$ 23,123	$ 31,352

Loan and Lease Receivables - Es

Loan and Lease Receivables - Estimated Fair Value of Impaired Loans Acquired at Acquisition (Details) - Acquired Impaired Loans - USD ($) $ in Thousands	Apr. 30, 2019	May 31, 2018
First Evanston Bancorp, Inc.
Accounts Notes And Loans Receivable [Line Items]
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
Oak Park River Forest Bankshares, Inc.
Accounts Notes And Loans Receivable [Line Items]
Undiscounted contractual cash flows	$ 65,223
Undiscounted cash flows not expected to be collected (non-accretable difference)	8,158
Undiscounted cash flows expected to be collected	57,065
Accretable yield at acquisition	(8,501)
Estimated fair value of impaired loans acquired at acquisition	$ 48,564

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, 2019	Dec. 31, 2018
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	$ 399,954	$ 428,768
Carrying Value	275,022	277,542
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	196,495	216,137
Carrying Value	142,435	146,808
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	161,742	173,962
Carrying Value	109,409	113,934
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	13,276	11,962
Carrying Value	4,562	3,779
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	27,320	24,972
Carrying Value	18,349	12,617
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Outstanding Balance	1,121	1,735
Carrying Value	$ 267	$ 404

Loan and Lease Receivables - _4

Loan and Lease Receivables - Summary of Changes in Accretable Yield for Acquired Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Receivables [Abstract]
Beginning balance	$ 46,538	$ 41,306	$ 37,115	$ 36,446
Additions			8,501	3,566
Accretion to interest income	(7,703)	(5,665)	(17,772)	(17,227)
Reclassification from nonaccretable difference, net	5,153	2,507	16,144	15,363
Ending balance	$ 43,988	$ 38,148	$ 43,988	$ 38,148

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, 2019	Dec. 31, 2018	Sep. 30, 2018
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	$ 3,831,090	$ 3,501,626	$ 3,455,802
Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	806,088	1,018,921
Loans and leases	784,611	986,286
Commercial Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,306,288	1,261,607	1,272,204
Commercial Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	400,422	473,262
Loans and leases	391,294	462,565
Residential Real Estate
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	749,103	704,902	705,196
Residential Real Estate | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	144,075	127,478
Loans and leases	141,855	124,659
Construction, Land Development, and Other Land
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	280,999	185,349	181,705
Construction, Land Development, and Other Land | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	40,778	38,494
Loans and leases	39,657	37,442
Commercial and Industrial
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	1,302,162	1,144,797	1,095,446
Commercial and Industrial | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	194,756	344,879
Loans and leases	187,413	328,672
Installment and Other
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	9,354	13,718	12,194
Installment and Other | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	1,303	1,831
Loans and leases	1,269	1,596
Lease Financing Receivables
Accounts Notes And Loans Receivable [Line Items]
Loans and leases	183,184	191,253	$ 189,057
Lease Financing Receivables | Acquired Non-impaired Loans and Leases
Accounts Notes And Loans Receivable [Line Items]
Unpaid Principal Balance	24,754	32,977
Loans and leases	$ 23,123	$ 31,352

Allowance for Loan and Lease _3

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Allowance for Loan and Lease Losses and Corresponding Loan and Lease Balances (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Allowance for loan and lease losses
Beginning balance	$ 31,132	$ 19,687	$ 25,201	$ 16,706
Provisions	5,931	5,842	16,321	14,913
Charge-offs	(5,686)	(2,421)	(11,314)	(9,228)
Recoveries	208	316	1,377	1,033
Ending balance	31,585	23,424	31,585	23,424
Ending balance:
Individually evaluated for impairment					$ 9,562		$ 6,422
Collectively evaluated for impairment					19,221		14,007
Allowance for loan and lease losses	31,585	19,687	31,585	23,424	31,585	$ 25,201	23,424
Loans and leases ending balance:
Individually evaluated for impairment					53,176		35,529
Collectively evaluated for impairment					3,502,892		3,126,105
Total loans and leases					3,831,090	3,501,626	3,455,802
Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2,802		2,995
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					275,022		294,168
Commercial Real Estate
Allowance for loan and lease losses
Beginning balance	8,934	6,453	7,540	4,794
Provisions	1,075	1,705	4,212	3,975
Charge-offs	(1,459)	(736)	(3,628)	(1,347)
Recoveries	3		429
Ending balance	8,553	7,422	8,553	7,422
Ending balance:
Individually evaluated for impairment					2,728		2,294
Collectively evaluated for impairment					4,458		3,413
Allowance for loan and lease losses	8,934	6,453	8,553	7,422	8,553	7,540	7,422
Loans and leases ending balance:
Individually evaluated for impairment					24,071		13,612
Collectively evaluated for impairment					1,139,782		1,104,484
Total loans and leases					1,306,288	1,261,607	1,272,204
Commercial Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					1,367		1,715
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					142,435		154,108
Residential Real Estate
Allowance for loan and lease losses
Beginning balance	2,171	1,648	1,751	1,638
Provisions	74	29	230	39
Charge-offs			(9)
Recoveries	6		279
Ending balance	2,251	1,677	2,251	1,677
Ending balance:
Individually evaluated for impairment					39		70
Collectively evaluated for impairment					1,612		1,150
Allowance for loan and lease losses	2,171	1,648	2,251	1,677	2,251	1,751	1,677
Loans and leases ending balance:
Individually evaluated for impairment					2,374		1,941
Collectively evaluated for impairment					637,320		582,292
Total loans and leases					749,103	704,902	705,196
Residential Real Estate | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					600		457
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					109,409		120,963
Construction, Land Development, and Other Land
Allowance for loan and lease losses
Beginning balance	691	332	466	222
Provisions	125	58	350	586
Charge-offs				(418)
Ending balance	816	390	816	390
Ending balance:
Collectively evaluated for impairment					802		390
Allowance for loan and lease losses	691	332	816	390	816	466	390
Loans and leases ending balance:
Collectively evaluated for impairment					276,437		177,502
Total loans and leases					280,999	185,349	181,705
Construction, Land Development, and Other Land | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					14
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					4,562		4,203
Commercial and Industrial
Allowance for loan and lease losses
Beginning balance	17,126	8,369	12,932	7,418
Provisions	4,198	3,579	10,550	8,959
Charge-offs	(3,561)	(858)	(5,740)	(5,539)
Recoveries	20	75	41	327
Ending balance	17,783	11,165	17,783	11,165
Ending balance:
Individually evaluated for impairment					6,795		4,044
Collectively evaluated for impairment					10,169		6,301
Allowance for loan and lease losses	17,126	8,369	17,783	11,165	17,783	12,932	11,165
Loans and leases ending balance:
Individually evaluated for impairment					26,731		19,962
Collectively evaluated for impairment					1,257,082		1,061,048
Total loans and leases					1,302,162	1,144,797	1,095,446
Commercial and Industrial | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					819		820
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					18,349		14,436
Installment and Other
Allowance for loan and lease losses
Beginning balance	67	30	49	41
Provisions	(12)	12	10	33
Charge-offs	(1)	(4)	(5)	(36)
Recoveries	1		1
Ending balance	55	38	55	38
Ending balance:
Individually evaluated for impairment							14
Collectively evaluated for impairment					53		21
Allowance for loan and lease losses	67	30	55	38	55	49	38
Loans and leases ending balance:
Individually evaluated for impairment							14
Collectively evaluated for impairment					9,087		11,722
Total loans and leases					9,354	13,718	12,194
Installment and Other | Loans Acquired with Deteriorated Credit Quality
Ending balance:
Loans acquired with deteriorated credit quality					2		3
Loans and leases ending balance:
Loans acquired with deteriorated credit quality					267		458
Lease Financing Receivables
Allowance for loan and lease losses
Beginning balance	2,143	2,855	2,463	2,593
Provisions	471	459	969	1,321
Charge-offs	(665)	(823)	(1,932)	(1,888)
Recoveries	178	241	627	706
Ending balance	2,127	2,732	2,127	2,732
Ending balance:
Collectively evaluated for impairment					2,127		2,732
Allowance for loan and lease losses	$ 2,143	$ 2,855	$ 2,127	$ 2,732	2,127	2,463	2,732
Loans and leases ending balance:
Collectively evaluated for impairment					183,184		189,057
Total loans and leases					$ 183,184	$ 191,253	$ 189,057

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
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ 453,000	$ 3,700,000	$ 6,400,000	$ 6,700,000
Commitments outstanding on troubled debt restructurings	500,000		500,000		$ 500,000
Recorded investment in troubled debt restructurings that subsequently defaulted within twelve months	0	0	348,000	340,000
Reserve for unfunded commitments	1,300,000		1,300,000		$ 1,200,000
Provisions for (credits to) unfunded commitments	51,000	441,000	78,000	496,000
Charge-offs or recoveries related to reserve for unfunded commitments	0	0	0	0
Individually Evaluated For Impairment
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	276,000	1,500,000	2,900,000	2,500,000
Collectively Evaluated For Impairment
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	850,000	2,000,000	3,400,000	5,100,000
Acquired Impaired Loans
Loans And Leases Receivable Disclosure [Line Items]
Increase (decrease) in allowance for loan and lease losses	$ (480,000)	$ 244,000	$ 260,000	$ (879,000)

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, 2019	Dec. 31, 2018
Financing Receivable Impaired [Line Items]
Recorded Investment	$ 53,176	$ 35,914
Unpaid Principal Balance	57,264	41,231
Related Allowance	9,562	6,649
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	15,636	6,110
Recorded Investment, With an allowance recorded	8,435	5,873
Unpaid Principal Balance, With no related allowance recorded	16,653	7,693
Unpaid Principal Balance, With an allowance recorded	9,246	6,313
Related Allowance	2,728	2,191
Residential Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	2,246	1,886
Recorded Investment, With an allowance recorded	128	251
Unpaid Principal Balance, With no related allowance recorded	2,356	1,858
Unpaid Principal Balance, With an allowance recorded	146	253
Related Allowance	39	61
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Recorded Investment, With no related allowance recorded	9,557	11,193
Recorded Investment, With an allowance recorded	17,174	10,601
Unpaid Principal Balance, With no related allowance recorded	10,510	13,961
Unpaid Principal Balance, With an allowance recorded	18,353	11,153
Related Allowance	$ 6,795	$ 4,397

Allowance for Loan and Lease _6

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Average Recorded Investment and Interest Income Recognized for Loans and Leases Considered Impaired (Details) - Loans Excluding Acquired Impaired Loans - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Financing Receivable Impaired [Line Items]
Average Recorded Investment	$ 45,170	$ 33,782
Interest Income Recognized	2,457	977
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	9,379	9,441
Average Recorded Investment, With an allowance recorded	8,238	5,022
Interest Income Recognized, With no related allowance recorded	761	232
Interest Income Recognized, With an allowance recorded	479	16
Residential Real Estate
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	1,914	1,910
Average Recorded Investment, With an allowance recorded	207	330
Interest Income Recognized, With no related allowance recorded	60	24
Interest Income Recognized, With an allowance recorded	7	3
Construction, Land Development, and Other Land
Financing Receivable Impaired [Line Items]
Interest Income Recognized, With no related allowance recorded		15
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With no related allowance recorded	11,889	8,018
Average Recorded Investment, With an allowance recorded	13,543	9,047
Interest Income Recognized, With no related allowance recorded	482	194
Interest Income Recognized, With an allowance recorded	$ 668	484
Installment and Other
Financing Receivable Impaired [Line Items]
Average Recorded Investment, With an allowance recorded		14
Interest Income Recognized, With an allowance recorded		$ 9

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, 2019	Dec. 31, 2018	Sep. 30, 2018
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 3,831,090	$ 3,501,626	$ 3,455,802
Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,306,288	1,261,607	1,272,204
Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	749,103	704,902	705,196
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	280,999	185,349	181,705
Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,302,162	1,144,797	1,095,446
Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	9,354	13,718	12,194
Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	183,184	191,253	$ 189,057
Loans Excluding Acquired Impaired Loans
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,556,068	3,224,084
Loans Excluding Acquired Impaired Loans | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,163,853	1,114,799
Loans Excluding Acquired Impaired Loans | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	639,694	590,968
Loans Excluding Acquired Impaired Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	276,437	181,570
Loans Excluding Acquired Impaired Loans | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,283,813	1,132,180
Loans Excluding Acquired Impaired Loans | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	9,087	13,314
Loans Excluding Acquired Impaired Loans | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	183,184	191,253
Loans Excluding Acquired Impaired Loans | Pass
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	3,095,248	2,870,431
Loans Excluding Acquired Impaired Loans | Pass | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,008,797	1,009,041
Loans Excluding Acquired Impaired Loans | Pass | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	608,106	553,665
Loans Excluding Acquired Impaired Loans | Pass | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	254,745	147,123
Loans Excluding Acquired Impaired Loans | Pass | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1,034,730	962,291
Loans Excluding Acquired Impaired Loans | Pass | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	8,916	9,997
Loans Excluding Acquired Impaired Loans | Pass | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	179,954	188,314
Loans Excluding Acquired Impaired Loans | Watch
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	312,935	253,552
Loans Excluding Acquired Impaired Loans | Watch | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	103,761	76,276
Loans Excluding Acquired Impaired Loans | Watch | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	10,986	29,522
Loans Excluding Acquired Impaired Loans | Watch | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	14,544	31,376
Loans Excluding Acquired Impaired Loans | Watch | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	183,458	112,996
Loans Excluding Acquired Impaired Loans | Watch | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	170	3,302
Loans Excluding Acquired Impaired Loans | Watch | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	16	80
Loans Excluding Acquired Impaired Loans | Special Mention
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	76,507	62,437
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	24,998	17,602
Loans Excluding Acquired Impaired Loans | Special Mention | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	17,975	5,656
Loans Excluding Acquired Impaired Loans | Special Mention | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	7,148	3,071
Loans Excluding Acquired Impaired Loans | Special Mention | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	24,289	34,314
Loans Excluding Acquired Impaired Loans | Special Mention | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,097	1,794
Loans Excluding Acquired Impaired Loans | Substandard
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	70,856	37,417
Loans Excluding Acquired Impaired Loans | Substandard | Commercial Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	26,297	11,880
Loans Excluding Acquired Impaired Loans | Substandard | Residential Real Estate
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	2,627	2,125
Loans Excluding Acquired Impaired Loans | Substandard | Commercial and Industrial
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	41,336	22,579
Loans Excluding Acquired Impaired Loans | Substandard | Installment and Other
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	1	15
Loans Excluding Acquired Impaired Loans | Substandard | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	595	818
Loans Excluding Acquired Impaired Loans | Doubtful
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	522	247
Loans Excluding Acquired Impaired Loans | Doubtful | Lease Financing Receivables
Financing Receivable Recorded Investment [Line Items]
Total loans and leases	$ 522	$ 247

Allowance for Loan and Lease _8

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of Contractual Delinquency Information (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	$ 3,831,090	$ 3,501,626	$ 3,455,802
Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,306,288	1,261,607	1,272,204
Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	749,103	704,902	705,196
Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	280,999	185,349	181,705
Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	1,302,162	1,144,797	1,095,446
Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	9,354	13,718	12,194
Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total loans and leases	183,184	191,253	$ 189,057
Acquired Non-Impaired and Originated Loans
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	63,730	50,297
Non-accrual	39,528	25,834
Current	3,492,338	3,173,787
Total loans and leases	3,556,068	3,224,084
Acquired Non-Impaired and Originated Loans | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	16,571	19,697
Acquired Non-Impaired and Originated Loans | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	7,631	4,766
Acquired Non-Impaired and Originated Loans | Commercial Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	20,775	18,288
Non-accrual	12,186	9,484
Current	1,143,078	1,096,511
Total loans and leases	1,163,853	1,114,799
Acquired Non-Impaired and Originated Loans | Commercial Real Estate | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	6,140	6,659
Acquired Non-Impaired and Originated Loans | Commercial Real Estate | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	2,449	2,145
Acquired Non-Impaired and Originated Loans | Residential Real Estate
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,225	7,014
Non-accrual	2,092	1,815
Current	636,469	583,954
Total loans and leases	639,694	590,968
Acquired Non-Impaired and Originated Loans | Residential Real Estate | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	632	4,488
Acquired Non-Impaired and Originated Loans | Residential Real Estate | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	501	711
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,203
Current	273,234	181,570
Total loans and leases	276,437	181,570
Acquired Non-Impaired and Originated Loans | Construction, Land Development, and Other Land | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	3,203
Acquired Non-Impaired and Originated Loans | Commercial and Industrial
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	34,746	21,137
Non-accrual	24,592	13,932
Current	1,249,067	1,111,043
Total loans and leases	1,283,813	1,132,180
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	9,136	5,829
Acquired Non-Impaired and Originated Loans | Commercial and Industrial | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,018	1,376
Acquired Non-Impaired and Originated Loans | Installment and Other
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	13	1,948
Non-accrual	1	12
Current	9,074	11,366
Total loans and leases	9,087	13,314
Acquired Non-Impaired and Originated Loans | Installment and Other | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	12	1,932
Acquired Non-Impaired and Originated Loans | Installment and Other | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due		4
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	1,768	1,910
Non-accrual	657	591
Current	181,416	189,343
Total loans and leases	183,184	191,253
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables | 30-59 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	651	789
Acquired Non-Impaired and Originated Loans | Lease Financing Receivables | 60-89 Days Past Due
Financing Receivable Recorded Investment Past Due [Line Items]
Total Past Due	$ 460	$ 530

Allowance for Loan and Lease _9

Allowance for Loan and Lease Losses and Reserve for Unfunded Commitments - Summary of TDR's by Loan Category (Details) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019USD ($)Loan	Dec. 31, 2018USD ($)Loan
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	29	22
Pre-Modification Outstanding Recorded Investment	$ 13,460	$ 11,039
Post-Modification Outstanding Recorded Investment	11,412	9,127
Charge-offs	2,048	1,912
Specific Reserves	$ 2,120	$ 2,246
Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	10	7
Pre-Modification Outstanding Recorded Investment	$ 2,204	$ 1,813
Post-Modification Outstanding Recorded Investment	2,204	1,813
Specific Reserves	$ 299	$ 213
Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	19	15
Pre-Modification Outstanding Recorded Investment	$ 11,256	$ 9,226
Post-Modification Outstanding Recorded Investment	9,208	7,314
Charge-offs	2,048	1,912
Specific Reserves	$ 1,821	$ 2,033
Commercial Real Estate | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	5	4
Pre-Modification Outstanding Recorded Investment	$ 1,476	$ 1,508
Post-Modification Outstanding Recorded Investment	1,476	1,508
Specific Reserves	$ 179	$ 113
Commercial Real Estate | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	8	9
Pre-Modification Outstanding Recorded Investment	$ 3,650	$ 2,512
Post-Modification Outstanding Recorded Investment	3,473	2,471
Charge-offs	177	41
Specific Reserves	$ 553	$ 743
Commercial and Industrial | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	3	2
Pre-Modification Outstanding Recorded Investment	$ 528	$ 191
Post-Modification Outstanding Recorded Investment	528	191
Specific Reserves	$ 120	$ 100
Commercial and Industrial | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	10	6
Pre-Modification Outstanding Recorded Investment	$ 7,493	$ 6,714
Post-Modification Outstanding Recorded Investment	5,622	4,843
Charge-offs	1,871	1,871
Specific Reserves	$ 1,268	$ 1,290
Residential Real Estate | Accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	2	1
Pre-Modification Outstanding Recorded Investment	$ 200	$ 114
Post-Modification Outstanding Recorded Investment	$ 200	$ 114
Residential Real Estate | Non-accruing
Financing Receivable Modifications [Line Items]
Number of Loans | Loan	1
Pre-Modification Outstanding Recorded Investment	$ 113
Post-Modification Outstanding Recorded Investment	$ 113

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Receivables [Abstract]
Beginning balance	$ 1,529	$ 1,238	$ 1,813	$ 1,061
Additions			113	37
Net payments	(242)	(8)	(291)	(56)
Net transfers from (to) non-accrual	917		569	188
Ending balance	2,204	1,230	2,204	1,230
Beginning balance	7,834	5,776	7,314	1,570
Additions	2,893	1,667	4,321	7,123
Net payments	(540)	(84)	(1,266)	(1,002)
Charge-offs	(62)		(592)	(144)
Net transfers from (to) accrual	(917)		(569)	(188)
Ending balance	9,208	7,359	9,208	7,359
Total troubled debt restructurings	$ 11,412	$ 8,589	$ 11,412	$ 8,589

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Transfers And Servicing [Abstract]
Beginning balance	$ 19,760	$ 21,587	$ 19,693	$ 21,400
Additions, net	1,789	1,533	4,340	5,681
Changes in fair value	(1,610)	(2,446)	(4,094)	(6,407)
Ending balance	$ 19,939	$ 20,674	$ 19,939	$ 20,674

Servicing Assets - Unpaid Princ

Servicing Assets - Unpaid Principal Balances of Loans Serviced for Others (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 1,315,203	$ 1,258,099
SBA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	1,197,725	1,151,915
USDA guaranteed loans
Loan portfolios serviced for:
Unpaid principal balances of loans serviced	$ 117,478	$ 106,184

Servicing Assets - Additional I

Servicing Assets - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accounts Notes And Loans Receivable [Line Items]
Changes in fair value of servicing assets	$ (1,610)	$ (2,446)	$ (4,094)	$ (6,407)
Loan Servicing Revenue [Member]
Accounts Notes And Loans Receivable [Line Items]
Fees and charges	$ 2,692	$ 2,622	$ 7,861	$ 7,605

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Banking And Thrift [Abstract]
Other real estate owned, beginning balance	$ 8,070	$ 6,402	$ 5,314	$ 10,626
Acquisitions of OREO through business combination			2,201
Net additions to OREO	1,840	307	3,916	1,527
Proceeds from sales of OREO	(1,391)	(2,008)	(2,722)	(7,130)
Gains (losses) on sales of OREO	38	489	11	380
Valuation adjustments	(26)	(299)	(189)	(512)
Other real estate owned, ending balance	$ 8,531	$ 4,891	$ 8,531	$ 4,891

Other Real Estate Owned - Addit

Other Real Estate Owned - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 8,531,000	$ 4,891,000	$ 8,531,000	$ 4,891,000	$ 8,070,000	$ 5,314,000	$ 6,402,000	$ 10,626,000
Residential consumer mortgage loans in process of foreclosure	2,900,000		2,900,000			2,300,000
Proceeds from sale of internally financed sales of OREO	0	$ 0	183,000	$ 444,000
Residential Real Estate
Real Estate [Line Items]
Foreclosed real estate properties recorded as result of obtaining physical possession of property	$ 688,000		$ 688,000			$ 838,000

Goodwill, Core Deposit Intang_3

Goodwill, Core Deposit Intangible and Other Intangible Assets - Summary of Changes in Goodwill, Core Deposit Intangible Assets and Customer Relationship Intangible Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance, Goodwill	$ 145,638	$ 127,536	$ 128,177	$ 54,562
Additions			17,461	72,974
Ending balance, Goodwill	145,638	127,536	145,638	127,536
Amortization	(2,003)	(1,898)	(5,735)	(3,795)
Core Deposits
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	32,982	33,917	30,360	16,720
Additions			6,220	19,060
Amortization	(1,936)	(1,822)	(5,534)	(3,685)
Ending balance	31,046	32,095	31,046	32,095
Accumulated amortization	$ 24,420	$ 17,151	$ 24,420	$ 17,151
Weighted average remaining amortization period	6 years 8 months 12 days	7 years 1 month 6 days	6 years 8 months 12 days	7 years 1 month 6 days
Customer Relationships
Schedule Of Goodwill And Intangible Assets [Line Items]
Beginning balance	$ 2,926	$ 3,194	$ 3,059
Additions				$ 3,216
Amortization	(67)	(67)	(200)	(89)
Ending balance	2,859	3,127	2,859	3,127
Accumulated amortization	$ 358	$ 89	$ 358	$ 89
Weighted average remaining amortization period	10 years 8 months 12 days	11 years 8 months 12 days	10 years 8 months 12 days	11 years 8 months 12 days

Goodwill, Core Deposit Intang_4

Goodwill, Core Deposit Intangible and Other Intangible Assets - Estimated Amortization Expense for Core Deposit Intangible, Customer Relationship Intangible and Other Intangible Assets Recognized (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Goodwill And Intangible Assets Disclosure [Abstract]
2019	$ 2,002
2020	7,577
2021	7,012
2022	6,440
2023	4,336
Thereafter	6,538
Total	$ 33,905	$ 33,419

Income Taxes - Additional Infor

Income Taxes - Additional Information (Details) - USD ($)	3 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2018
Income Tax [Line Items]
Effective tax rate		27.70%	24.40%
Net income tax benefit related to exercise of stock options		$ (64,000)	$ (64,000)
Net income tax benefit related to vesting of restricted shares		$ (362,000)	$ (362,000)
Corporate federal income tax rate		21.00%		35.00%
Net income tax benefit	$ (724,000)
Deferred tax assets, net		$ 33,400,000			$ 35,600,000
Oak Park River Forest Bankshares, Inc.
Income Tax [Line Items]
Decrease in deferred tax assets, net		$ (4,900,000)

Deposits - Composition of Depos

Deposits - Composition of Deposits (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Deposits [Abstract]
Non-interest-bearing demand deposits	$ 1,221,431	$ 1,192,873
Interest-bearing checking accounts	372,049	296,339
Money market demand accounts	745,154	640,401
Other savings	471,878	476,418
Time deposits (below $250,000)	966,866	911,603
Time deposits ($250,000 and above)	302,936	232,282
Total deposits	$ 4,080,314	$ 3,749,916

Deposits - Additional Informati

Deposits - Additional Information (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Deposits [Abstract]
Brokered deposits	$ 81,000,000	$ 50,000,000

Federal Home Loan Bank Advanc_3

Federal Home Loan Bank Advances - Summary of FHLB Advances (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank advances	$ 506,000	$ 425,000
Weighted average cost	2.05%	2.56%

Federal Home Loan Bank Advanc_4

Federal Home Loan Bank Advances - Additional Information (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank, total fixed-rate advances	$ 506,000,000
Federal home loan bank, required investment conversion ratio	0.045
Additional borrowing capacity from FHLB	$ 1,400,000,000	$ 1,300,000,000
Federal home loan bank advances maximum borrowing capacity as percentage of total assets	35.00%
Minimum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.04%
Federal home loan bank fixed rate advances, maturity date	2019-10
Maximum
Federal Home Loan Bank Advances [Line Items]
Federal home loan bank advances, Fixed interest rate	2.08%
Federal home loan bank fixed rate advances, maturity date	2019-12

Other Borrowings - Summary of O

Other Borrowings - Summary of Other Borrowings (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Apr. 30, 2019	Dec. 31, 2018
Debt Disclosure [Abstract]
Securities sold under agreements to repurchase	$ 32,290		$ 34,166
Line of credit		$ 5,700
Total	$ 32,290		$ 34,166

Other Borrowings - Additional I

Other Borrowings - Additional Information (Details) - USD ($)	Oct. 10, 2019	Apr. 30, 2019	May 31, 2019	Jul. 31, 2017	Sep. 30, 2019	Dec. 31, 2018	Apr. 30, 2017	Oct. 13, 2016
Line Of Credit Facility [Line Items]
Line of credit facility, amount		$ 5,700,000
Repayment of lines of credit			$ 5,700,000	$ 16,200,000	$ 11,335,000
Short-term credit lines available for use, outstanding					$ 0	$ 0
LIBOR Rate
Line Of Credit Facility [Line Items]
Interest rate spread		2.25%
Ridgestone | Correspondent Bank | Credit agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount								$ 30,000,000
Ridgestone | Correspondent Bank | Amended Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, revolving credit conversion to non-revolving line of credit, description					In April 2017, the revolving line of credit was amended to a non-revolving line of credit as long as the outstanding balance exceeds $5.0 million.
Line of credit facility, revolving credit conversion to non-revolving line of credit, threshold amount							$ 5,000,000
Threshold amount for conversion of line of credit into revolving line of credit							5,000,000
Revolving line of credit facility, maximum borrowing capacity							$ 5,000,000
Line of credit facility, maturity date					Oct. 10, 2019
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 | Fourth Amendment Revolving Credit Agreement
Line Of Credit Facility [Line Items]
Line of credit facility, amount					$ 0	$ 0
Ridgestone | Correspondent Bank | Fourth Amendment Revolving Credit Agreement | Subsequent Event
Line Of Credit Facility [Line Items]
Line of credit facility, amount	$ 15,000,000
Line of credit facility, extended maturity date	Oct. 9, 2020
Line of credit facility, interest rate terms	The amended revolving line of credit bears interest at either the LIBOR plus 195 basis points or the Prime Rate minus 75 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 75 basis points. At September 30, 2019 and December 31, 2018, the line of credit had no outstanding balance, therefore an interest rate option has not been selected.
Ridgestone | Correspondent Bank | Fourth Amendment Revolving Credit Agreement | Subsequent Event | LIBOR Rate
Line Of Credit Facility [Line Items]
Interest rate spread	2.25%
Ridgestone | Correspondent Bank | Fourth Amendment Revolving Credit Agreement | Subsequent Event | Prime Rate
Line Of Credit Facility [Line Items]
Interest rate spread	0.50%

Other Borrowings - Summary of S

Other Borrowings - Summary of Short-term Credit Lines Available for Use (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Federal Reserve Bank of Chicago Discount Window Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 419,086	$ 293,613
Available Federal Funds Line
Debt Instrument [Line Items]
Short-term credit lines available for use	$ 105,000	$ 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, 2019	Dec. 31, 2018
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	$ 46,500	$ 46,500
Total liability, at carrying value	37,207	36,768
Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	35,000	35,000
RidgeStone Capital Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	1,500	1,500
First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Total liability, at par	10,000	10,000
Junior Subordinated Debentures
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Discount	$ (9,293)	$ (9,732)
Junior Subordinated Debentures | Metropolitan Statutory Trust 1
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 17, 2034
Contractual Rate	4.93%	5.58%
Junior Subordinated Debentures | Metropolitan Statutory Trust 1 | Three-month LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	2.79%	2.79%
Junior Subordinated Debentures | RidgeStone Capital Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Jun. 30, 2033
Contractual Rate	6.38%	6.38%
Junior Subordinated Debentures | RidgeStone Capital Trust I | Five-year LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Five-year LIBOR
Interest Rate Spread	3.50%	3.50%
Junior Subordinated Debentures | First Evanston Bancorp Trust I
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Stated Maturity	Mar. 15, 2035
Contractual Rate	3.90%	4.57%
Junior Subordinated Debentures | First Evanston Bancorp Trust I | Three-month LIBOR
Shares Subject To Mandatory Redemption By Settlement Terms [Line Items]
Interest Rate Spread, Description	Three-month LIBOR
Interest Rate Spread	1.78%	1.78%

Junior Subordinated Debenture_3

Junior Subordinated Debentures - Additional Information (Details) - USD ($)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Principal amount	$ 46,500,000	$ 46,500,000
Accrued interest payable	4,778,000	3,484,000
Metropolitan Statutory Trust 1
Debt Instrument [Line Items]
Principal amount	$ 35,000,000	$ 35,000,000
Metropolitan Statutory Trust 1 | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	4.93%	5.58%
Accrued interest payable	$ 69,000	$ 84,000
Metropolitan Statutory Trust 1 | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread	2.79%	2.79%
RidgeStone Capital Trust I
Debt Instrument [Line Items]
Principal amount	$ 1,500,000	$ 1,500,000
RidgeStone Capital Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	6.38%	6.38%
Accrued interest payable	$ 0	$ 0
RidgeStone Capital Trust I | Junior Subordinated Debentures | Five-year LIBOR
Debt Instrument [Line Items]
Interest rate spread	3.50%	3.50%
First Evanston Bancorp Trust I
Debt Instrument [Line Items]
Principal amount	$ 10,000,000	$ 10,000,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures
Debt Instrument [Line Items]
Contractual rate	3.90%	4.57%
Accrued interest payable	$ 17,000	$ 21,000
First Evanston Bancorp Trust I | Junior Subordinated Debentures | Three-month LIBOR
Debt Instrument [Line Items]
Interest rate spread	1.78%	1.78%

Commitments and Contingent Li_3

Commitments and Contingent Liabilities - Summary of Minimum Annual Rental Commitments for Operating Leases (Details) $ in Thousands	Sep. 30, 2019USD ($)
Commitments And Contingencies Disclosure [Abstract]
2019	$ 1,166
2020	4,455
2021	3,798
2022	2,230
2023	1,294
Thereafter	3,303
Total	$ 16,246

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Commitments And Contingencies Liabilities [Line Items]
Rental expenses		$ 1,400,000	$ 1,400,000	$ 4,200,000	$ 4,200,000
Sublease income		190,000	223,000	560,000	569,000
Minimum rental to be received in future on subleases		1,300,000		$ 1,300,000
Sublease contract maturity year				2025
Data processing		$ 4,062,000	$ 2,724,000	$ 11,055,000	$ 15,396,000
Fixed rate loan commitments maturity year				2042
Variable rate loan commitments maturity year				2048
Maximum
Commitments And Contingencies Liabilities [Line Items]
Commitments to make loans period				90 days
Loan commitments fixed interest rate		19.50%		19.50%
Loan commitments variable interest rate		10.25%		10.25%
Minimum
Commitments And Contingencies Liabilities [Line Items]
Loan commitments fixed interest rate		2.50%		2.50%
Loan commitments variable interest rate		2.02%		2.02%
Contract termination
Commitments And Contingencies Liabilities [Line Items]
Data processing	$ 8,100,000
Remaining data processing cost balance		$ 0		$ 0

Commitments and Contingent Li_5

Commitments and Contingent Liabilities - Summary of Contract or Notional Amount of Outstanding Loan and Lease Commitments (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	$ 51,885	$ 76,081
Variable Rate	970,502	963,062
Total	1,022,387	1,039,143
Commitments to Extend Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	51,101	74,099
Variable Rate	930,778	928,991
Total	981,879	1,003,090
Letters of Credit
Commitments And Contingencies Liabilities [Line Items]
Fixed Rate	784	1,982
Variable Rate	39,724	34,071
Total	$ 40,508	$ 36,053

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, 2019	Jun. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 1,031,933		$ 817,656
Servicing assets, at fair value	19,939	$ 19,760	19,693	$ 20,674	$ 21,587	$ 21,400
Derivative assets	10,288		10,740
Derivative liabilities	11,093		4,243
U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	42,842		52,667
U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	177,858		186,498
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	98,602		60,233
Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	47,194		34,173
Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	32,834		6,609
Fair Value, Measurements, Recurring
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	19,939		19,693
Derivative assets	10,288		10,740
Derivative liabilities	11,093		4,243
Fair Value, Measurements, Recurring | Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	2,944
Fair Value, Measurements, Recurring | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	4,704
Fair Value, Measurements, Recurring | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	42,842		52,667
Fair Value, Measurements, Recurring | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	177,858		186,498
Fair Value, Measurements, Recurring | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	98,602		60,233
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Residential | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	329,010		272,963
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Residential | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	120,060		83,621
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Commercial | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	152,033		90,434
Fair Value, Measurements, Recurring | Mortgage-Backed Securities; Commercial | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	31,500		30,458
Fair Value, Measurements, Recurring | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	47,194		34,173
Fair Value, Measurements, Recurring | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	32,834		6,609
Fair Value, Measurements, Recurring | Level 1 | Mutual Funds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	2,944
Fair Value, Measurements, Recurring | Level 1 | U.S. Treasury Notes
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	42,842		52,667
Fair Value, Measurements, Recurring | Level 1 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value			2,844
Fair Value, Measurements, Recurring | Level 2
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Derivative assets	10,288		10,740
Derivative liabilities	11,093		4,243
Fair Value, Measurements, Recurring | Level 2 | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	4,008
Fair Value, Measurements, Recurring | Level 2 | U.S. Government Agencies
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	177,858		186,498
Fair Value, Measurements, Recurring | Level 2 | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	98,407		60,038
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Residential | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	329,010		272,963
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Residential | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	120,060		83,621
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Commercial | Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	152,033		90,434
Fair Value, Measurements, Recurring | Level 2 | Mortgage-Backed Securities; Commercial | Non-Agency
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	31,500		30,458
Fair Value, Measurements, Recurring | Level 2 | Corporate Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	47,194		34,173
Fair Value, Measurements, Recurring | Level 2 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	32,834		3,074
Fair Value, Measurements, Recurring | Level 3
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Servicing assets, at fair value	19,939		19,693
Fair Value, Measurements, Recurring | Level 3 | Equity Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	696
Fair Value, Measurements, Recurring | Level 3 | Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value	$ 195		195
Fair Value, Measurements, Recurring | Level 3 | Other Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Securities available-for-sale, at fair value			$ 691

Fair Value Measurement - Additi

Fair Value Measurement - Additional Information (Details) - USD ($)	Sep. 30, 2019	Sep. 30, 2018
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Abstract]
Fair value, assets, to or from level 3 transfers, amount	$ 0	$ 0
Fair value, liabilities, to or from level 3 transfers, amount	0	0
Fair value, equity, to or from level 3 transfers, amount	$ 0	$ 0

Fair Value Measurement - Summ_2

Fair Value Measurement - Summary of Financial Assets Measured at Fair Value on Recurring Basis Using Significant Unobservable Inputs (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Investment Securities
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	$ 886	$ 1,052
Acquired assets at fair value		314
Amortization	4	4
Change in unrealized gain	1	11
Balance, end of period	891	1,381
Servicing Assets
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Balance, beginning of period	19,693	21,400
Additions, net	4,340	5,680
Change in fair value	(4,094)	(6,406)
Balance, end of period	$ 19,939	$ 20,674

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, 2019
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Expected weighted average loan life	1 month 6 days
Minimum | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.048
Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected weighted average loan life	9 years 6 months
Maximum | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.240
Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Expected weighted average loan life	4 years 6 months
Weighted Average | Discount Rate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.122
Obligations of States, Municipalities, and Political Subdivisions
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Unobservable Inputs	0.024
Debt Securities, Available-for-sale, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Securities, Available-for-sale, Measurement Input [Extensible List]	us-gaap:MeasurementInputDefaultRateMember
Obligations of States, Municipalities, and Political Subdivisions | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.024
Single Issuer Trust Preferred
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Impact to Valuation from an Increased or Higher Input Value	Decrease
Debt Instrument, Valuation Technique [Extensible List]	us-gaap:ValuationTechniqueDiscountedCashFlowMember
Debt Instrument, Measurement Input [Extensible List]	us-gaap:MeasurementInputDefaultRateMember
Single Issuer Trust Preferred | Minimum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.049
Single Issuer Trust Preferred | Maximum
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.054
Single Issuer Trust Preferred | Weighted Average
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.058
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	0.027
Servicing Assets | Maximum | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.219
Servicing Assets | Weighted Average | Prepayment Speeds
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis [Line Items]
Unobservable Inputs	0.137

Fair Value Measurement - Summ_4

Fair Value Measurement - Summary of Assets Measured at Fair Value on Non-recurring Basis, Excluding Acquired Impaired Loans (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Commercial Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	$ 21,343	$ 9,792
Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	2,335	2,076
Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	19,936	17,397
Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	8,531	5,314
Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	15,472	14,489
Level 3 | Commercial Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	21,343	9,792
Level 3 | Residential Real Estate
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	2,335	2,076
Level 3 | Commercial and Industrial
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	19,936	17,397
Level 3 | Other Real Estate Owned
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	8,531	5,314
Level 3 | Assets Held For Sale
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Assets, Fair Value	$ 15,472	$ 14,489

Fair Value Measurement - Summ_5

Fair Value Measurement - Summary of Estimated Fair Values of Financial Instruments and Levels Within Fair Value Hierarchy (Details) - USD ($) $ in Thousands		Sep. 30, 2019	Apr. 30, 2019	Dec. 31, 2018
Financial assets
Cash and due from banks		$ 75,275		$ 30,190
Interest bearing deposits with other banks		33,564		91,670
Securities held-to-maturity, fair value		4,502		97,739
Restricted stock, at cost		24,331		19,202
Loans held for sale		7,176		19,827
Loans and lease receivables, net (less impaired loans at fair value)		3,799,505		3,476,425
Accrued interest receivable		13,013		10,863
Financial liabilities
Line of credit			$ 5,700
Federal Home Loan Bank advances		506,000		425,000
Securities sold under agreements to repurchase		32,290		34,166
Junior subordinated debentures issued to capital trusts, net		37,207		36,768
Level 1 | Carrying Amount
Financial assets
Cash and due from banks		75,275		30,190
Level 1 | Estimated Fair Value
Financial assets
Cash and due from banks		75,275		30,190
Level 2 | Carrying Amount
Financial assets
Interest bearing deposits with other banks		33,564		91,670
Securities held-to-maturity, fair value		4,417		99,266
Restricted stock, at cost		24,331		19,202
Financial liabilities
Non-interest-bearing deposits		1,221,431		1,192,873
Interest-bearing deposits		2,858,883		2,557,043
Accrued interest payable		4,778		3,484
Federal Home Loan Bank advances		506,000		425,000
Securities sold under agreements to repurchase		32,290		34,166
Level 2 | Estimated Fair Value
Financial assets
Interest bearing deposits with other banks		33,564		91,670
Securities held-to-maturity, fair value		4,503		97,739
Restricted stock, at cost		24,331		19,202
Financial liabilities
Non-interest-bearing deposits		1,221,431		1,192,873
Interest-bearing deposits		2,867,646		2,554,329
Accrued interest payable		4,778		3,484
Federal Home Loan Bank advances		506,000		425,000
Securities sold under agreements to repurchase		32,290		34,166
Level 3 | Carrying Amount
Financial assets
Loans held for sale		7,176		19,827
Loans and lease receivables, net (less impaired loans at fair value)	[1]	3,755,891		3,447,160
Accrued interest receivable		13,013		10,863
Financial liabilities
Junior subordinated debentures issued to capital trusts, net		37,207		36,768
Level 3 | Estimated Fair Value
Financial assets
Loans held for sale		7,922		21,654
Loans and lease receivables, net (less impaired loans at fair value)	[1]	3,677,608		3,407,652
Accrued interest receivable		13,013		10,863
Financial liabilities
Junior subordinated debentures issued to capital trusts, net		$ 42,496		$ 42,351
[1]	In accordance with the prospective adoption of ASU 2016-01, the fair value of loans and lease receivables, net (less impaired loans at fair value) as of September 30, 2019 was measured using an exit price notion. The fair value as of December 31, 2018 was measured using an entry price notion.

Derivative Instruments and He_3

Derivative Instruments and Hedge Activities - Summary of Derivative Financial Instruments and Classification on Consolidated Statements of Financial Condition (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Derivatives Fair Value [Line Items]
Notional Amount	$ 306,175,000	$ 548,969,000
Other Assets	10,288,000	10,740,000
Other Liabilities	11,093,000	4,243,000
Other Interest Rate Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	296,656,000
Other Assets	10,288,000
Other Liabilities	11,076,000
Derivatives Designated as Hedging Instruments | Interest Rate Swaps | Cash Flow Hedges
Derivatives Fair Value [Line Items]
Notional Amount	0	250,000,000
Other Assets		6,699,000
Derivatives Not Designated As Hedging Instruments | Other Credit Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	9,519,000	4,424,000
Other Liabilities	17,000	6,000
Derivatives Not Designated As Hedging Instruments | Other Interest Rate Derivatives
Derivatives Fair Value [Line Items]
Notional Amount	296,656,000	294,545,000
Other Assets	10,288,000	4,041,000
Other Liabilities	$ 11,076,000	$ 4,237,000

Derivative Instruments and He_4

Derivative Instruments and Hedge Activities - Additional Information (Details) - USD ($)	1 Months Ended	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Derivative [Line Items]
Derivative notional amount	$ 306,175,000	$ 306,175,000		$ 306,175,000		$ 548,969,000
Unrealized gain (loss) to be reclassified as an decrease to interest expense during the next twelve months	(85,000)	(85,000)		(85,000)
Credit valuation adjustment increase (decrease) to non-interest income		(219,000)	$ 13,000	(592,000)	$ (25,000)
Interest Rate Swaps | Interest Expense
Derivative [Line Items]
Decrease in FHLB expense		(364,000)	(428,000)	(1,600,000)	(863,000)
Other Interest Rate Derivatives
Derivative [Line Items]
Derivative notional amount	296,656,000	296,656,000		$ 296,656,000
Derivative maturity date, start year				Apr. 30, 2020
Derivative maturity date, end year				Jan. 31, 2030
Derivative instruments transaction fees		170,000	230,000	$ 886,000	1,200,000
Other Credit Derivatives
Derivative [Line Items]
Derivative notional amount	9,500,000	9,500,000		9,500,000		4,400,000
Derivative instruments transaction fees		73,000	35,000	73,000	61,000
Credit valuation adjustment increase (decrease) to non-interest income		(7,000)	$ (1,000)	(11,000)	$ (4,000)
Derivatives Designated as Hedging Instruments | Interest Rate Swaps | Cash Flow Hedges
Derivative [Line Items]
Derivative notional amount	0	0		0		250,000,000
Termination of designated as cash flow hedges to reduce interest risk	250,000,000
Transaction, net of tax	383,000
Remaining balance in accumulated other comprehensive income	$ 378,000	$ 378,000		$ 378,000
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

Derivative Instruments and He_5

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, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI	$ (251)	$ 1,070	$ (5,484)	$ 6,702
Interest Rate Swaps
Derivative [Line Items]
Amount of Gain (Loss) Recognized in OCI			(5,484)	6,702
Amount of Gain Reclassified from OCI to Income as a Decrease to Interest Expense			$ 1,643	$ 863

Derivative Instruments and He_6

Derivative Instruments and Hedge Activities - Summary of Other Interest Rate Derivatives (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional Amount	$ 306,175,000	$ 548,969,000
Derivative assets fair value	10,288,000	10,740,000
Derivative liabilities fair value	11,093,000	$ 4,243,000
Other Interest Rate Derivatives
Derivative [Line Items]
Notional Amount	296,656,000
Derivative assets fair value	10,288,000
Derivative liabilities fair value	$ 11,076,000
Weighted average pay rates	4.74%
Weighted average receive rates	4.37%
Weighted average maturity	6 years 9 months 18 days

Derivative Instruments and He_7

Derivative Instruments and Hedge Activities - Summary of Company's Interest Rate Derivative and Offsetting Positions (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Derivative Instruments And Hedging Activities Disclosure [Abstract]
Gross amounts recognized	$ 10,288	$ 10,740
Net amount presented in the Consolidated Statements of Financial Condition	10,288	10,740
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(1)	(2,823)
Collateral posted	(10,287)	(7,917)
Gross amounts recognized	11,093	4,243
Net amount presented in the Consolidated Statements of Financial Condition	11,093	4,243
Gross amounts not offset in the Consolidated Statements of Financial Condition
Offsetting derivative positions	(1)	(2,823)
Collateral posted	$ (11,092)	(1,317)
Net credit exposure		$ 103

Share-Based Compensation - Addi

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

May 15, 2019

Apr. 30, 2019

Oct. 03, 2017

Jul. 06, 2017

Oct. 31, 2014

Sep. 30, 2019

Jun. 30, 2019

Mar. 31, 2019

Dec. 31, 2018

Sep. 30, 2018

Jun. 30, 2018

Mar. 31, 2018

Sep. 30, 2019

Sep. 30, 2018

Dec. 31, 2018

Dec. 31, 2017

Dec. 31, 2016

Dec. 31, 2015

Jun. 30, 2017

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

Common stock, voting par value

$ 0.01

$ 0.01

$ 0.01

$ 0.01

Proceeds from the exercise of stock options

$ 2,359,000

$ 1,702,000

Oak Park River Forest Bankshares, Inc.

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

Consideration paid in cash

$ 4,200,000

$ 6,163,000

Business combination conversion of outstanding options

35,870

Restricted Shares

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

Income tax benefit

$ 378,000

$ 178,000

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

50,992

141,207

5,000

126,157

Number of options exercised

3,472

116,048

50,662

58,639

51,763

8,000

86,750

Omnibus Plan

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

Number of common stock reserved and available for issuance

1,550,000

Number of common shares available for future grants

1,186,226

1,186,226

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

192,199

Restricted shares vested

37,310

2,975

Fair value of restricted shares, vested

$ 699,000

$ 62,000

Fair value of unvested restricted stock awards

$ 5,800,000

$ 5,800,000

Omnibus Plan | Performance-based Restricted Shares

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

Shares of restricted voting common stock granted

20,975

11,165

Period for number of shares earned under return on average assets

3 years

3 years

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

50.00%

Maximum target percentage 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

192,199

131,157

Common stock, voting par value

$ 0.01

$ 0.01

$ 0.01

$ 0.01

Shares vested

898

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

4 years

Shares vest on grant date

115,496

102,559

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

3 years

Shares vest on grant date

54,147

15,165

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

683

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

89,000

148,748

Number of shares outstanding

1,449,072

1,598,872

1,449,072

1,598,872

Award contractual term

5 years 7 months 6 days

6 years 7 months 6 days

Options vested

0

Proceeds from the exercise of stock options

$ 1,400,000

$ 1,700,000

Income tax benefit

$ 70,000

$ 449,000

BYB Plan | Maximum

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

Number of common shares available for future grants

2,476,122

BYB Plan | Time Options Grants

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

Award contractual term

10 years

BYB Plan | Time Options Grants | Maximum

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

Award vesting period

5 years

BYB Plan | Time Options Grants | Minimum

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

Award vesting period

1 year

BYB Plan | Performance Options Grants

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

Award contractual term

10 years

BYB Plan | Performance Options Grants | Maximum

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

Award vesting period

5 years

BYB Plan | Performance Options Grants | Minimum

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

Award vesting period

1 year

FEB Plan

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

Number of options exercised

81,182

56,404

Number of shares outstanding

543,201

624,383

543,201

624,383

Award contractual term

4 years 6 months

5 years 2 months 12 days

Proceeds from the exercise of stock options

$ 912,000

$ 601,000

Income tax benefit

$ 189,000

$ 168,000

Conversion calculation percentage

472.50%

472.50%

FEB Plan | Restricted Shares

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

Number of shares outstanding

0

0

Share-Based Compensation - Summ

Share-Based Compensation - Summary of Changes in Restricted Shares (Details) - Omnibus Plan - Restricted Shares - $ / shares	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of shares, beginning balance	196,480
Number of shares, granted	192,199
Number of shares, vested	(37,310)	(2,975)
Number of shares, forfeited	(27,880)
Number of shares, ending balance	323,489	196,480
Weighted average grant date fair value, beginning balance	$ 21.66
Weighted average grant date fair value, granted	18.70
Weighted average grant date fair value, vested	22.01
Weighted average grant date fair value, forfeited	19.75
Weighted average grant date fair value, ending balance	$ 20.03	$ 21.66

Share-Based Compensation - Su_2

Share-Based Compensation - Summary of Stock Compensation Expense (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Employee Service Share Based Compensation Allocation Of Recognized Period Costs [Line Items]
Total share-based compensation (benefit) - stock options	$ (119)	$ 510
Income tax benefit (expense)	(33)	142
Unrecognized compensation expense	$ 21	$ 209
Weighted-average amortization period remaining	6 months	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	$ 1,357	$ 638
Income tax benefit	378	178
Unrecognized compensation expense	$ 4,917	$ 3,379
Weighted-average amortization period remaining	2 years 9 months 18 days	3 years 1 month 6 days

Share-Based Compensation - Su_3

Share-Based Compensation - Summary Activity in shares Subjected to Options and Weighted Average Exercise Prices (Details) - USD ($) $ / shares in Units, $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
BYB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Beginning balance	1,598,872
Number of Shares, Exercised	(89,000)	(148,748)
Number of Shares, Forfeited	(60,800)
Number of Shares, Ending balance	1,449,072	1,598,872
Number of Shares, Exercisable	1,411,572
Weighted Average Exercise Price, Beginning balance	$ 11.84
Weighted Average Exercise Price, Exercised	16.25
Weighted Average Exercise Price, Forfeited	16.25
Weighted Average Exercise Price, Ending balance	11.38	$ 11.84
Weighted Average Exercise Price, Exercisable	$ 11.25
Intrinsic Value, Beginning balance	$ 7,713
Intrinsic Value, Exercised	253
Intrinsic Value, Ending balance	9,420	$ 7,713
Intrinsic Value, Exercisable	$ 9,359
Weighted Average Remaining Contractual Term (in Years)	5 years 7 months 6 days	6 years 7 months 6 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	5 years 7 months 6 days
Number of Shares, Granted			0	212,400	1,634,568
FEB Plan
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Number of Shares, Beginning balance	624,383
Number of Shares, Exercised	(81,182)	(56,404)
Number of Shares, Ending balance	543,201	624,383
Number of Shares, Exercisable	543,201
Weighted Average Exercise Price, Beginning balance	$ 11.31
Weighted Average Exercise Price, Exercised	11.24
Weighted Average Exercise Price, Ending balance	11.32	$ 11.31
Weighted Average Exercise Price, Exercisable	$ 11.32
Intrinsic Value, Beginning balance	$ 3,339
Intrinsic Value, Exercised	677
Intrinsic Value, Ending balance	3,561	$ 3,339
Intrinsic Value, Exercisable	$ 3,561
Weighted Average Remaining Contractual Term (in Years)	4 years 6 months	5 years 2 months 12 days
Weighted Average Remaining Contractual Term (in Years), Exercisable	4 years 6 months

Earnings per Share - Additional

Earnings per Share - Additional Information (Details) - shares	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share Basic [Line Items]
Shares outstanding	37,831,356	36,042,914	37,094,083	32,341,087
Stock Options
Earnings Per Share Basic [Line Items]
Shares outstanding			1,992,273	2,312,294
Restricted Stock Award
Earnings Per Share Basic [Line Items]
Shares outstanding			323,489	194,455

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, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 15,342	$ 13,211	$ 12,597	$ 17,121	$ 14,536	$ 2,768	$ 6,768	$ 41,150	$ 24,072
Dividends on preferred shares	196				196			587	587
Net income available to common stockholders	$ 15,146				$ 14,340			$ 40,563	$ 23,485
Weighted-average common stock outstanding:
Weighted-average common stock outstanding (basic)	37,831,356				36,042,914			37,094,083	32,341,087
Incremental shares	655,824				915,295			724,785	947,570
Weighted-average common stock outstanding (dilutive)	38,487,180				36,958,209			37,818,868	33,288,657
Basic earnings per common share	$ 0.40				$ 0.40			$ 1.09	$ 0.73
Diluted earnings per common share	$ 0.39				$ 0.39			$ 1.07	$ 0.71

Stockholders' Equity - Summary

Stockholders' Equity - Summary of Preferred and Common Stock (Details) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Class Of Stock [Line Items]
Common stock, voting par value	$ 0.01	$ 0.01
Common stock, voting shares authorized	150,000,000	150,000,000
Common stock, voting shares issued	38,169,126	36,343,239
Common stock, voting shares outstanding	38,169,126	36,343,239
Series B 7.5% Fixed to Floating Non-Cumulative Perpetual Preferred Stock
Class Of Stock [Line Items]
Par value	$ 0.01	$ 0.01
Shares authorized	50,000	50,000
Shares issued	10,438	10,438
Shares outstanding	10,438	10,438

Stockholders' Equity - Summar_2

Stockholders' Equity - Summary of Preferred and Common Stock (Parenthetical) (Details)	9 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Series B 7.5% Fixed to Floating Non-Cumulative Perpetual Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage	7.50%	7.50%

Stockholders' Equity - Addition

Stockholders' Equity - Additional Information (Details) - USD ($)	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2016	Nov. 01, 2019
Class Of Stock [Line Items]
Dividends declared and paid			$ 587,000	$ 587,000
Approximate percentage of shares authorized to be repurchased	3.30%		3.30%
Subsequent Event
Class Of Stock [Line Items]
Aggregate number of shares authorized to repurchase						1,250,000
Series B Preferred Stock
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage					7.50%
Preferred stock, liquidation preference per share					$ 1,000
Preferred stock fixed dividend close date					Dec. 30, 2021
Preferred stock redemption price per share					$ 1,000
Dividends declared and paid	$ 196,000	$ 196,000	$ 587,000	$ 587,000
Series B Preferred Stock | Three-month LIBOR
Class Of Stock [Line Items]
Preferred stock, dividend rate, percentage					5.41%

Consolidated Statements of Ch_4

Consolidated Statements of Change in Accumulated Other Comprehensive Income (Loss) - Schedule of Consolidated Statements of Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands	3 Months Ended							9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	$ 717,675	$ 668,749	$ 650,672	$ 629,861	$ 616,406	$ 462,936	$ 458,578	$ 650,672	$ 458,578
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)									(763)
Cumulative-effect adjustment (ASU 2016-01)								(1,440)
Other comprehensive income (loss), net of tax	2,309	5,071	4,519	2,864	(2,027)	(921)	(3,564)	11,899	(6,512)
Ending balance	735,866	717,675	668,749	650,672	629,861	616,406	462,936	735,866	629,861
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			4,763	7,813			2,913	4,763	2,913
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)									687
Other comprehensive income (loss), net of tax								(5,142)	4,213
Ending balance	(379)			4,763	7,813			(379)	7,813
Unrealized Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance			(14,261)	(20,175)			(8,000)	(14,261)	(8,000)
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)									(1,450)
Cumulative-effect adjustment (ASU 2016-01)								(1,440)
Other comprehensive income (loss), net of tax								17,041	(10,725)
Ending balance	1,340			(14,261)	(20,175)			1,340	(20,175)
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income Loss [Line Items]
Beginning balance	(1,348)	(6,419)	(9,498)	(12,362)	(10,335)	(9,414)	(5,087)	(9,498)	(5,087)
Reclassification of certain income tax effects from accumulated other comprehensive income (loss)							(763)
Other comprehensive income (loss), net of tax	2,309	5,071	4,519	2,864	(2,027)	(921)	(3,564)
Ending balance	$ 961	$ (1,348)	$ (6,419)	$ (9,498)	$ (12,362)	$ (10,335)	$ (9,414)	$ 961	$ (12,362)