TCF Financial 10-Q 31 Jul 19 2019 Q2 Quarterly report Financial data

Cover Page

Cover Page - shares	6 Months Ended
	Jun. 30, 2019	Jul. 26, 2019
Cover page.
Document Transition Report	false
Document Quarterly Report	true
Entity Incorporation, State or Country Code	MI
Title of 12(b) Security	Common Stock
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Shell Company	false
Entity Registrant Name	CHEMICAL FINANCIAL CORPORATION
Entity Central Index Key	0000019612
Document Type	10-Q
Entity File Number	000-08185
Document Period End Date	Jun. 30, 2019
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Entity Small Business	false
Entity Common Stock, Shares Outstanding		71,558,755
City Area Code	800
Local Phone Number	867-9757
Trading Symbol	CHFC
Security Exchange Name	NASDAQ
Entity Tax Identification Number	38-2022454
Entity Address, Postal Zip Code	48226
Entity Address, Address Line One	333 W. Fort Street,
Entity Address, Address Line Two	Suite 1800
Entity Address, City or Town	Detroit,
Entity Address, State or Province	MI

Consolidated Statements of Fina

Consolidated Statements of Financial Position - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Cash and cash equivalents:
Cash and cash due from banks	$ 200,034	$ 228,527
Interest-bearing deposits with the Federal Reserve Bank and other banks and federal funds sold	392,724	267,312
Total cash and cash equivalents	592,758	495,839
Investment securities:
Carried at fair value	3,369,872	3,021,832
Held-to-maturity, at amortized cost (fair value of $575,502 and $618,672, respectively)	566,046	624,099
Total investment securities	3,935,918	3,645,931
Loans held-for-sale, at fair value	33,019	85,030
Loans	15,861,903	15,269,779
Allowance for loan losses	(115,967)	(109,984)
Net loans	15,745,936	15,159,795
Premises and equipment	123,708	123,442
Loan servicing rights, at fair value	60,658	71,013
Goodwill	1,134,568	1,134,568
Core deposit intangibles	25,835	28,556
Interest receivable and other assets	839,365	754,167
Total assets	22,491,765	21,498,341
Deposits:
Noninterest-bearing	3,925,777	3,809,252
Interest-bearing	11,953,659	11,784,030
Total deposits	15,879,436	15,593,282
Collateralized customer deposits	291,671	382,687
Short-term borrowings	2,615,000	2,035,000
Long-term borrowings	426,069	426,002
Interest payable and other liabilities	326,054	225,110
Total liabilities	19,538,230	18,662,081
Shareholders' equity
Preferred stock, none issued	0	0
Common stock issued	71,559	71,460
Additional paid-in capital	2,212,665	2,209,761
Retained earnings	699,712	616,149
Accumulated other comprehensive loss	(30,401)	(61,110)
Total shareholders' equity	2,953,535	2,836,260
Total liabilities and shareholders' equity	$ 22,491,765	$ 21,498,341

Consolidated Statements of Fi_2

Consolidated Statements of Financial Position (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Held-to-maturity, fair value	$ 575,502	$ 618,672
Loan servicing rights, at fair value	$ 60,658	$ 71,013
Preferred stock, no par value (dollars per share)	$ 0	$ 0
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	135,000,000	135,000,000
Common stock, shares issued (in shares)	71,558,755	71,460,119
Common stock, shares outstanding (in shares)	71,558,755	71,460,119

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Interest income
Interest and fees on loans	$ 188,875	$ 165,388	$ 372,167	$ 322,206
Interest on investment securities:
Taxable	21,214	14,706	41,715	27,125
Tax-exempt	7,297	5,998	14,467	11,554
Dividends on nonmarketable equity securities	2,401	2,189	4,139	4,090
Interest on deposits with the Federal Reserve Bank and other banks and federal funds sold	1,641	1,301	2,921	2,541
Total interest income	221,428	189,582	435,409	367,516
Interest expense
Interest on deposits	42,011	19,707	81,009	35,624
Interest on collateralized customer deposits	537	641	1,164	1,165
Interest on short-term borrowings	11,345	10,408	20,523	18,574
Interest on long-term borrowings	2,374	1,289	4,728	2,753
Total interest expense	56,267	32,045	107,424	58,116
Net interest income	165,161	157,537	327,985	309,400
Provision for loan losses	7,502	9,572	9,561	15,828
Net interest income after provision for loan losses	157,659	147,965	318,424	293,572
Noninterest income
Net gain on sale of loans and other mortgage banking revenue	4,532	8,844	5,426	21,379
Net gain on sale of investment securities	4,160	3	4,247	3
Other	8,504	7,494	13,717	14,985
Total noninterest income	38,164	38,018	63,021	78,572
Operating expenses
Salaries, wages and employee benefits	62,129	56,148	122,146	111,705
Occupancy	7,786	7,679	16,063	15,690
Equipment and software	7,076	8,276	14,055	15,935
Outside processing and service fees	12,206	10,673	23,932	21,029
Merger expenses	3,042	0	8,466	0
Other	18,764	21,785	35,356	41,812
Total operating expenses	111,003	104,561	220,018	206,171
Income before income taxes	84,820	81,422	161,427	165,973
Income tax expense	15,226	12,434	28,891	25,389
Net income	$ 69,594	$ 68,988	$ 132,536	$ 140,584
Earnings per common share:
Basic earnings per common share (dollars per share)	$ 0.97	$ 0.97	$ 1.85	$ 1.97
Diluted earnings per common share (dollars per share)	$ 0.96	$ 0.96	$ 1.84	$ 1.95
Service charges and fees on deposit accounts
Noninterest income
Noninterest income	$ 8,247	$ 9,690	$ 16,214	$ 19,124
Wealth management revenue
Noninterest income
Noninterest income	6,966	7,188	12,838	13,499
Other charges and fees for customer services
Noninterest income
Noninterest income	$ 5,755	$ 4,799	$ 10,579	$ 9,582

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 69,594	$ 68,988	$ 132,536	$ 140,584
Other comprehensive income (loss), net of tax:
Unrealized holding gains (losses) on securities carried at fair value arising during the period	36,809	(11,622)	74,253	(39,229)
Reclassification adjustment for (gains) losses included in net income	(4,160)	(3)	(4,247)	(3)
Tax effect	(6,856)	2,441	(14,701)	8,239
Net unrealized gains (losses) on securities carried at fair value, net of tax	25,793	(9,184)	55,305	(30,993)
Unrealized gains (losses) on interest rate swaps designated as cash flow hedges	(21,229)	4,102	(28,781)	12,065
Reclassification adjustment for (gains) losses included in net income	(1,256)	(589)	(2,544)	(347)
Tax effect	4,722	(738)	6,578	(2,461)
Net unrealized (losses) gains on interest rate swaps designated as cash flow hedges, net of tax	(17,763)	2,775	(24,747)	9,257
Adjustment for pension and other postretirement benefits	96	142	191	284
Tax effect	(20)	(30)	(40)	(60)
Net adjustment for pension and other postretirement benefits	76	112	151	224
Other comprehensive income (loss), net of tax	8,106	(6,297)	30,709	(21,512)
Total comprehensive income, net of tax	$ 77,700	$ 62,691	$ 163,245	$ 119,072

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands		Total	Stock options	Common stock	Common stockStock options	Additional paid-in capital	Additional paid-in capitalStock options	Retained earnings	Accumulated other comprehensive income (loss)
Changes in Stockholders' Equity
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]	$ 1,339						$ 1,680	$ (341)
Beginning balance at Dec. 31, 2017		2,668,749		$ 71,207		$ 2,203,637		419,403	(25,498)
Changes in Stockholders' Equity
Comprehensive income		119,072						140,584	(21,512)
Cash dividends		(40,137)						40,137
Net shares issued under share-based compensation plans			$ (2,102)		$ 211		$ (2,313)
Share-based compensation expense		4,078		0		4,078
Ending balance at Jun. 30, 2018		2,750,999		71,418		2,205,402		521,530	(47,351)
Beginning balance at Mar. 31, 2018		2,704,703		71,350		2,201,803		472,604	(41,054)
Changes in Stockholders' Equity
Comprehensive income		62,691						68,988	(6,297)
Cash dividends		(20,062)						(20,062)
Net shares issued under share-based compensation plans			1,241		68		1,173
Share-based compensation expense		2,426		0		2,426
Ending balance at Jun. 30, 2018		2,750,999		71,418		2,205,402		521,530	(47,351)
Beginning balance at Dec. 31, 2018		2,836,260		71,460		2,209,761		616,149	(61,110)
Changes in Stockholders' Equity
Comprehensive income		163,245						132,536	30,709
Cash dividends		(48,973)						(48,973)
Net shares issued under share-based compensation plans			(2,126)		99		(2,225)
Share-based compensation expense		5,129		0		5,129
Ending balance at Jun. 30, 2019		2,953,535		71,559		2,212,665		699,712	(30,401)
Beginning balance at Mar. 31, 2019		2,897,509		71,551		2,209,860		654,605	(38,507)
Changes in Stockholders' Equity
Comprehensive income		77,700						69,594	8,106
Cash dividends		(24,487)						(24,487)
Net shares issued under share-based compensation plans			$ 57		$ 8		$ 49
Share-based compensation expense		2,756		0		2,756
Ending balance at Jun. 30, 2019		$ 2,953,535		$ 71,559		$ 2,212,665		$ 699,712	$ (30,401)
[1]	Refer to Note 1 , Basis of Presentation and Significant Accounting Policies, Note 6 , Other Real Estate Owned and Repossessed Assets and Note 20 , Accumulated Other Comprehensive Loss for further details on the changes in accounting policy.

Consolidated Statements of Ch_2

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends declared per common share (dollars per share)	$ 0.34	$ 0.28	$ 0.68	$ 0.56

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Statement of Cash Flows [Abstract]
Repayments of Other Debt	$ 0	$ 42,000
Cash flows from operating activities
Net income	132,536	140,584
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	9,561	15,828
Gains on sales of loans	(11,538)	(5,531)
Proceeds from sales of loans	392,730	392,570
Valuation change in loans held-for-sale	1,730	216
Loans originated for sale, net of repayments	(330,969)	(379,584)
Net gains on sale of investment securities	(4,247)	(3)
Net (gains) losses from sales/writedowns of other real estate and repossessed assets	(807)	98
Depreciation of premises and equipment	8,527	8,384
Amortization of intangible assets	2,721	2,864
Additions to loan servicing rights	(4,242)	(4,251)
Valuation change in loan servicing rights	14,597	(2,272)
Net amortization of premiums and discounts on investment securities	12,744	9,123
Share-based compensation expense	5,129	4,078
Deferred income tax expense	3,783	4,473
Change in deferred tax valuation allowance	0	(72)
Net increase in interest receivable and other assets	(126,406)	(15,498)
Net increase (decrease) in interest payable and other liabilities	101,202	(5,671)
Net cash provided by operating activities	207,051	165,336
Investment securities - carried at fair value
Proceeds from maturities, calls and principal reductions	338,123	157,185
Proceeds from sales and redemptions	205,331	4,215
Purchases	(772,263)	(775,497)
Investment securities – held-to-maturity:
Proceeds from maturities, calls and principal reductions	1,880	85,027
Purchases	(1,549)	(11,240)
Net increase in loans	(602,373)	(439,390)
Proceeds from sales of other real estate and repossessed assets	5,311	7,646
Purchases of premises and equipment, net of disposals	(8,793)	(7,458)
Proceeds from returns of investment in equity method investments	162	269
Net cash used in investing activities	(834,171)	(979,243)
Cash flows from financing activities
Net increase in interest- and noninterest-bearing demand deposits and savings accounts	388	247,254
Net increase in time deposits	285,766	661,479
Net increase in collateralized customer deposits and other short-term borrowings	488,984	58,702
Cash dividends paid	(48,973)	(40,137)
Proceeds from directors’ stock plans and exercise of stock options, net of shares withheld	520	2,558
Cash paid for payroll taxes upon conversion of share-based awards	(2,646)	(4,660)
Net cash provided by financing activities	724,039	883,196
Net increase in cash and cash equivalents	96,919	69,289
Cash and cash equivalents at beginning of period	495,839	455,991
Cash and cash equivalents at end of period	592,758	525,280
Supplemental disclosures of cash flow information:
Interest paid	107,783	56,575
Net income tax (refunds) payments	(4,709)	4,599
Non-cash activities:
Loans transferred to other real estate and repossessed assets	6,729	5,093
Net transfer of loans held-for-sale to (from) loans held-for-investment	$ 58
Net transfer of loans held-for-sale to (from) loans held-for-investment		$ (2,171)

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Basis of Presentation and Significant Accounting Policies	Basis of Presentation and Significant Accounting Policies Nature of Operations Chemical Financial Corporation ("Corporation" or "Chemical") operates in a single operating segment — commercial banking. The Corporation is a financial holding company, headquartered in Detroit, Michigan, that operates through one commercial bank, Chemical Bank. Chemical Bank operates within Michigan, Ohio and Northern Indiana as a Michigan state-chartered commercial bank. Chemical Bank operates through an internal organizational structure of six regional banking units and offers a full range of traditional banking and fiduciary products and services to the residents and business customers in the Corporation's geographical market areas. The products and services offered by the regional banking units, through branch banking offices, are generally consistent throughout the Corporation, as is the pricing of those products and services. The marketing of products and services throughout the Corporation's regional banking units is generally uniform, as many of the markets served by the regional banking units overlap. The distribution of products and services is generally uniform throughout the Corporation's regional banking units and is achieved primarily through retail branch banking offices, automated teller machines and electronically accessed banking products. The Corporation's primary sources of revenue are interest from its loan products and investment securities, service charges and fees from customer deposit accounts, wealth management revenue and net gain on sale of loans and other mortgage banking revenue. Basis of Presentation and Principles of Consolidation The accompanying unaudited Consolidated Financial Statements of the Corporation and its subsidiaries have been prepared in accordance with United States ("U.S.") generally accepted accounting principles ("GAAP") for interim financial information and with instructions to Form 10-Q, Securities and Exchange Commission ("SEC") rules and interpretive releases and prevailing practices within the banking industry and Rule 10-01 of Regulation S-X. Accordingly, the interim Consolidated Financial Statements do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the Corporation’s Consolidated Financial Statements and footnotes thereto included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2018 . In the opinion of management, the accompanying unaudited interim Consolidated Financial Statements contain all adjustments believed necessary to present fairly the financial condition and results of operations of the Corporation for the periods presented. All significant income and expenses are recorded on the accrual basis. Intercompany accounts and transactions have been eliminated in preparing the Consolidated Financial Statements. Operating results for the six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 . Pending Merger with TCF Financial Corporation Chemical and TCF Financial Corporation ("TCF") have entered into an Agreement and Plan of Merger, dated as of January 27, 2019, which we refer to as the merger agreement. Under the merger agreement, Chemical and TCF have agreed to combine their respective companies in a merger of equals, pursuant to which TCF will merge with and into Chemical, with Chemical continuing as the surviving entity, in a transaction we refer to as the merger. Immediately following the merger or at such later time as the parties may mutually agree, Chemical Bank will merge with and into TCF National Bank, with TCF National Bank as the surviving bank, in a transaction we refer to as the bank merger. The merger has received all necessary regulatory approvals in addition to approvals from the shareholders of both companies. The pending transaction is anticipated to close on August 1, 2019, subject to satisfaction of customary closing conditions. The transaction is discussed in more detail in Note 2 . Use of Estimates Management makes estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and accompanying footnotes. Estimates that are particularly susceptible to significant change include the determination of the allowance for loan losses, expected cash flows from acquired loans, income taxes and the valuation of loan servicing rights. Actual results could differ from these estimates. Reclassifications Certain amounts appearing in the Consolidated Financial Statements and notes thereto for prior periods have been reclassified to conform to the current presentation. The reclassification had no effect on net income or shareholders’ equity as previously reported, except in case of the cumulative effect adjustment of change in accounting policy as noted. Recently Adopted Accounting Principles Standard Description Adoption Date Effect on the financial statements ASU No. 2014-09 - Revenue from Contracts with Customers (Topic 606) ASU No. 2016-08 - Principal versus Agent Considerations ASU No. 2016-10 - Identifying Performance Obligations and Licensing ASU No. 2016-12 - Narrow-scope Improvements and Practical Expedients ("Updates to Topic 606") The core principle of the Updates to 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. The standard is intended to clarify and converge the revenue recognition principles under GAAP and International Financial Reporting Standards and to streamline revenue recognition requirements in addition to expanding required revenue recognition disclosures. January 1, 2018 under the modified retrospective method A large majority of the Corporation's revenue is derived from net interest income, which is excluded from the scope of the guidance. Following detailed review of the Corporation's revenue streams not derived from net interest income on financial assets and liabilities, management identified the recognition of gains from other real estate sales financed by the Corporation to be in the scope of this amended guidance. Effective January 1, 2018, revenue for new seller financed other real estate owned sales is determined according to the Updates to Topic 606. If all qualifications are met, gains associated with the sales are recognized into income at the time of closing and therefore not deferred. The cumulative effect of the Updates to Topic 606 increased retained earnings by $1.2 million upon adoption. Additional required disclosures have been included in Note 15, Revenue from Contracts with Customers. The adoption is not expected to have a material impact on the Corporation's net income on an ongoing basis. Refer to Note 6, Other Real Estate Owned and Repossessed Assets, for further detail. ASU No. 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01") ASU 2016-01 amended current guidance by: (i) requiring equity investments with readily determinable fair values to be measured at fair value with changes in fair value recognized in net income, (ii) allowing an entity to measure equity investments that do not have readily determinable fair values at either fair value or cost minus impairment, changes in measurement is recognized in net income, (iii) simplifying impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iv) eliminating the requirement to disclose the methods and assumptions used to estimate the fair value of financial instruments measured at amortized cost; (v) requiring the use of exit price notion when measuring the fair value of financial instruments; (vi) requiring recognition of changes in the fair value related to instrument-specific credit risk in other comprehensive income if financial liabilities are measured at fair value, (vii) requiring separate presentation in financial statements by measurement category, and (viii) clarifying that an entity should evaluate the need for valuation allowance on deferred tax assets related to available-for-sale securities in combination with the entity’s other deferred tax assets. January 1, 2018 using a modified retrospective approach with the exception of disclosure requirements which are adopted on a prospective basis The Corporation identified available-for-sale investment securities qualifying as equity investments in the securities portfolio at January 1, 2018. The adoption resulted in recognizing the unrealized fair value related to the identified equity investments as a cumulative effect to retained earnings of $0.3 million. In addition, the Corporation has updated disclosures related to the fair value of financial instruments to the use of the exit price notion. Standard Description Adoption Date Effect on the financial statements ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts as Cash Payments ("ASU 2016-15") ASU 2016-15 was issued to reduce diversity in practice and prevent financial statement restatements by clarifying the presentation and classification of cash receipts and cash payments within the statement of cash flows. Cash flow issues include: debt prepayment or debt extinguishment costs, settlement of insurance claims, proceeds from the settlement of corporate-owned and bank-owned life insurance policies, distribution received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. January 1, 2018 using retrospective application The adoption did not have a material effect on the presentation of our Consolidated Statements of Cash Flows, as current policies are either already in-line with the clarifications in the updated guidance, or the related cash flows are not material. ASU No. 2017-07 - Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost ("ASU 2017-07") ASU 2017-07 improves the income statement presentation of net periodic benefit cost for an entity's pension and postretirement plans. The standard requires employers to disaggregate current service costs from other components of net benefit cost and present it with other compensation cost. Additionally net benefit cost becomes eligible for capitalization. January 1, 2018 using the retrospective transition method The adoption did not have a material effect on the Consolidated Statements of Income during the year ended December 31, 2018. ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvement to Account for Hedging Activities ("ASU 2017-12") ASU 2017-12 eliminates the separate measurement of hedge ineffectiveness as well as the benchmark interest rate concept when applying hedge risk to variable-rate instruments. It also allows a company to elect to perform subsequent effectiveness assessments qualitatively if the initial quantitative hedge effectiveness assessment is found to be highly effective. January 1, 2018 with a cumulative effect adjustment The early adoption resulted in a cumulative adjustment from opening retained earnings to accumulated other comprehensive income of $3 thousand, which represented all previously recognized hedge ineffectiveness. ASU No. 2018-15 - Intangible-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract ("ASU 2018-15") ASU 2018-15 clarifies the accounting treatment for implementation costs for hosting arrangements that are service contracts. The amendments in this update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal use software in accordance with subtopic 350-40. Under this guidance costs for implementation activities during the development stage shall be capitalized. The said capitalized-costs shall be expensed over the term of the hosting arrangement. Third quarter of 2018 applied retrospectively The early adoption in the third quarter of 2018 did not have a material effect on the Consolidated Financial Statements. Standard Description Adoption Date Effect on the financial statements ASU No. 2016-02 - Leases (Topic 842) ASU No. 2018-10 - Codification Improvements to Topic 842, Leases ASU No. 2018-11 - Leases (Topic 842): Targeted Improvements ASU No. 2018-20 - Leases (Topic 842): Narrow Scope Improvements for Lessors ASU No. 2019-01 - Leases (Topic 842): Codification Improvements In February 2016, the FASB established Topic 842, Leases, by issuing Accounting Standards Update (ASU), No. 2016-02, which requires lessees to recognize leases on-balance sheet, lessors to classify leases as sales-type, direct financing, or operating, and disclose key information about leasing arrangements. Topic 842 was subsequently amended by ASU No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842; ASU No. 2018-10, Codification Improvements to Topic 842, Leases; ASU No. 2018-11, Targeted Improvements; ASU No. 2018-20, Narrow Scope Improvements for Lessors; and ASU No. 2019-01, Leases (Topic 842): Codification Improvements. This guidance provides that lessees will be required to recognize the following for all operating leases (with the exception of short-term leases): 1) a lease liability, which is the present value of a lessee's obligation to make lease payments, and 2) a right-of-use (ROU) 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. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. Upon adoption, a modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. January 1, 2019 Upon adoption as of January 1, 2019, the Corporation elected certain practical expedients offered through the guidance, including foregoing the restatement of comparative periods, the use of hindsight, and the 'package of practical expedients' whereby it did not reassess (i) whether any expired or existing contracts contain leases, (ii) the lease classification for any expired or existing leases and (iii) initial direct costs for any existing leases. Effective during the six months ended 2019 , the Corporation also adopted the following standards, none of which had a material impact to the Corporation's financial statements or financial statement disclosures: Standard Effective Date 2017-06 Plan Accounting: Defined Benefit Pension Plans (Topic 960) January 1, 2019 2018-07 Compensation - Stock Compensation (Topic 718) January 1, 2019 2018-08 Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made January 1, 2019 2018-09 Codification Improvements January 1, 2019 2018-16 Derivatives and Hedging (Topic 815): Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes January 1, 2019

Mergers and Acquisitions

Mergers and Acquisitions	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Mergers and Acquisitions	Mergers and Acquisitions Pending Merger with TCF Financial Corporation On January 27, 2019 , Chemical entered into the merger agreement with TCF under which the companies will combine in an all-stock merger of equals transaction. Under the terms of the merger agreement, which was unanimously approved by the boards of directors of both companies, TCF will merge with and into Chemical. Immediately following the merger, Chemical Bank will merge with and into TCF National Bank, with TCF National Bank as the surviving bank. The combined holding company and bank will operate under the TCF name and brand following the closing of the transaction. TCF is headquartered in Wayzata, Minnesota with reported assets of approximately $24.4 billion as of March 31, 2019 . On June 7, 2019, Chemical and TCF received shareholder approval and subsequently received all necessary regulatory approvals to complete the merger. Under the terms of the merger agreement, TCF shareholders will receive 0.5081 shares of Chemical common stock for each share of TCF common stock based on a fixed exchange ratio, equivalent to $21.58 per TCF share based on the closing price as of January 25, 2019. Each outstanding share of 5.70% Series C Non-Cumulative Perpetual Preferred Stock of TCF will be converted into the right to receive one share of a newly created series of preferred stock of Chemical. Once the merger is completed, Chemical will be renamed and operate as TCF Financial Corporation and will trade on NASDAQ under the ticker symbol "TCF". The merger is expected to close on August 1, 2019, subject to satisfaction of customary closing conditions.

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Fair value, as defined by GAAP, is the price that would be received to sell an asset or paid to transfer a liability in an orderly transaction between market participants. A fair value measurement assumes that the transaction to sell the asset or transfer the liability occurs in the principal market for the asset or liability or, in the absence of a principal market, the most advantageous market for the asset or liability. The price in the principal (or most advantageous) market used to measure the fair value of the asset or liability is not adjusted for transaction costs. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for market activities that are usual and customary for transactions involving such assets and liabilities; it is not a forced transaction. Market participants are buyers and sellers in the principal market that are (i) independent, (ii) knowledgeable, (iii) able to transact and (iv) willing to transact. The Corporation utilizes fair value measurements to record fair value adjustments to certain assets and liabilities and to determine fair value disclosures. Investment securities — carried at fair value, loans held-for-sale, loan servicing rights ("LSRs") and derivatives are recorded at fair value on a recurring basis. Additionally, the Corporation may be required to record other assets, such as impaired loans, goodwill, other intangible assets, other real estate and repossessed assets, at fair value on a nonrecurring basis. These nonrecurring fair value adjustments typically involve the application of lower of cost or market accounting or write-downs of individual assets. The Corporation determines the fair value of its financial instruments based on a three-level hierarchy established by GAAP. The classification and disclosure of assets and liabilities within the hierarchy is based on whether the inputs to the valuation methodology used for measurement are observable or unobservable. Observable inputs reflect market-derived or market-based information obtained from independent sources, while unobservable inputs reflect management's estimates about market data. The three levels of inputs that may be used to measure fair value within the GAAP hierarchy are as follows: Level 1 Valuation is based upon quoted prices for identical instruments traded in active markets. Level 2 Valuation is based upon quoted prices for similar instruments in active markets, quoted prices for identical or similar instruments in markets that are not active, and model-based valuation techniques for which all significant assumptions are observable in the market. Level 2 valuations for the Corporation include government and government-sponsored enterprise debt obligations, including securities issued by the Federal Home Loan Bank ("FHLB"), Federal Home Loan Mortgage Corporation, Federal National Mortgage Association, Federal Farm Credit Bank, Student Loan Marketing Corporation and the Small Business Administration, securities issued by certain state and political subdivisions, residential mortgage-backed securities, collateralized mortgage obligations, corporate bonds and available-for-sale trust preferred securities. Valuations are obtained from a third-party pricing service for these investment securities. Additionally included in Level 2 valuations are loans held for sale and derivative assets and liabilities. Level 3 Valuation is generated from model-based techniques that use at least one significant assumption not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in pricing the asset or liability. Valuation techniques include use of option pricing models, discounted cash flow models, yield curves and similar techniques. The determination of fair value requires management judgment or estimation and generally is corroborated by external data, which includes third-party pricing services. Level 3 valuations for the Corporation include impaired loans, goodwill, core deposit intangible assets, LSRs and other real estate and repossessed assets. A description of the valuation methodologies used for instruments measured at fair value, as well as the general classification of such instruments pursuant to the valuation hierarchy, is set forth below. These valuation methodologies were applied to all of the Corporation's financial assets and financial liabilities carried at fair value and all financial instruments disclosed at fair value. Transfers of assets or liabilities between levels of the fair value hierarchy are recognized at the beginning of the reporting period, when applicable. In general, fair value is based upon quoted market prices, where available. If quoted market prices are not available, fair value is based upon third-party pricing services when available. Fair value may also be based on internally developed models that primarily use, as inputs, observable market-based parameters. Valuation adjustments may be required to record financial instruments at fair value. Any such valuation adjustments are applied consistently over time. The Corporation's valuation methodologies may produce a fair value calculation that may not be indicative of net realizable value or reflective of future fair values. While management believes the Corporation's valuation methodologies are appropriate and consistent with other market participants, the use of different methodologies or assumptions to determine the fair value of certain financial instruments could result in a different estimate of fair value at the reporting date. Furthermore, the fair value amounts may change significantly after the date of the statement of financial position from the amounts reported in the Consolidated Financial Statements and related notes. Assets and Liabilities Recorded at Fair Value on a Recurring Basis Investment securities: Investment securities are recorded at fair value on a recurring basis with the exception of those classified as held-to-maturity. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are generally measured using independent pricing models or other model-based valuation techniques that include market inputs, such as benchmark yields, reported trades, broker dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data and industry and economic events. Loans held-for-sale: The Corporation elected the fair value option for all loans held-for-sale. Accordingly, loans held-for-sale are recorded at fair value on a recurring basis. The fair values of loans held-for-sale are based on the market price for similar loans sold in the secondary market, and therefore, are classified as Level 2 valuations. Loan servicing rights: The Corporation has elected to account for all LSRs under the fair value measurement method. A third party valuation model is used to determine the fair value at the end of each reporting period utilizing a discounted cash flow analysis using interest rates and prepayment speed assumptions currently quoted for comparable instruments and a discount rate determined by management. Because of the nature of the valuation inputs, the Corporation classifies loan servicing rights as Level 3. Refer to Note 8 , Loan Servicing Rights, for the assumptions included in the valuation of loan servicing rights. Derivatives: The Corporation enters into interest rate lock commitments with prospective borrowers to be sold into the secondary market and forward commitments for the future delivery of mortgage loans to third party investors, which are carried at fair value on a recurring basis. The fair value of these commitments is based on the fair value of related mortgage loans determined using observable market data. Interest rate lock commitments are adjusted for expectations of exercise and funding. This adjustment is not considered to be a material input. The Corporation classifies interest rate lock commitments and forward contracts related to mortgage loans to be delivered for sale as recurring Level 2. Derivative instruments held or issued for risk management or customer-initiated activities are traded in over-the counter markets where quoted market prices are not readily available. Fair value for over-the-counter derivative instruments is measured on a recurring basis using third party models that use primarily market observable inputs, such as yield curves and option volatilities. The fair value for these derivatives may include a credit valuation adjustment that is determined by applying a credit spread for the counterparty or the Corporation, as appropriate, to the total expected exposure of the derivative after considering collateral and other master netting arrangements. These adjustments, which are considered Level 3 inputs, are based on estimates of current credit spreads to evaluate the likelihood of default. The Corporation assessed the significance of the impact of the credit valuation adjustments on the overall valuation of its derivative positions at both June 30, 2019 and December 31, 2018 and it was determined that the credit valuation adjustments were not significant to the overall valuation of its derivatives. As a result, the Corporation classifies its risk management interest rate swaps designated as cash flow hedges and customer-initiated derivatives valuations in Level 2 of the fair value hierarchy. Written and purchased option derivatives consist of instruments to facilitate an equity-linked time deposit product (the "Power Equity CD"). The Power Equity CD is a time deposit that provides the purchaser a guaranteed return of principal at maturity plus a potential equity return, while the Corporation receives a known stream of funds based on equity returns. The written and purchased options are mirror derivative instruments which are carried at fair value on the Consolidated Statements of Financial Position. Fair value measurements for the Power Equity CD are determined using quoted prices of underlying stocks, along with other terms and features of the derivative instrument. As a result, the Power Equity CD derivatives are classified as Level 2 valuations. Disclosure of Recurring Basis Fair Value Measurements For assets and liabilities measured at fair value on a recurring basis, quantitative disclosures about the fair value measurements for each major category of assets and liabilities follow: (Dollars in thousands) Quoted Prices In Active Markets for Identical Assets Significant Other Significant Total June 30, 2019 Investment securities – carried at fair value: Government and government-sponsored enterprises $ — $ 295,726 $ — $ 295,726 State and political subdivisions — 444,085 — 444,085 Residential mortgage-backed securities — 353,622 — 353,622 Collateralized mortgage obligations — 1,939,695 — 1,939,695 Corporate bonds — 289,312 — 289,312 Trust preferred securities — 47,432 — 47,432 Total investment securities – carried at fair value — 3,369,872 — 3,369,872 Loans held-for-sale — 33,019 — 33,019 Loan servicing rights — — 60,658 60,658 Derivative assets: Customer-initiated derivatives — 69,024 — 69,024 Interest rate lock commitments — 2,687 — 2,687 Power Equity CD — 751 — 751 Risk management derivatives — 606 — 606 Total derivatives — 73,068 — 73,068 Total assets at fair value $ — $ 3,475,959 $ 60,658 $ 3,536,617 Derivative liabilities: Customer-initiated derivatives — 70,707 — 70,707 Forward contracts related to mortgage loans to be delivered for sale — 661 — 661 Power Equity CD — 751 — 751 Risk management derivatives — 25,060 — 25,060 Total derivatives — 97,179 — 97,179 Total liabilities at fair value $ — $ 97,179 $ — $ 97,179 (Dollars in thousands) Quoted Prices In Active Markets for Identical Assets Significant Other Significant Total December 31, 2018 Investment securities – carried at fair value: Government and government-sponsored enterprises $ — $ 351,700 $ — $ 351,700 State and political subdivisions — 516,286 — 516,286 Residential mortgage-backed securities — 213,428 — 213,428 Collateralized mortgage obligations — 1,601,298 — 1,601,298 Corporate bonds — 293,063 — 293,063 Trust preferred securities — 46,057 — 46,057 Total investment securities – carried at fair value — 3,021,832 — 3,021,832 Loans held-for-sale — 85,030 — 85,030 Loan servicing rights — — 71,013 71,013 Derivative assets: Customer-initiated derivatives — 26,680 — 26,680 Interest rate lock commitments — 1,049 — 1,049 Power Equity CD — 718 — 718 Risk management derivatives — 10,148 — 10,148 Total derivatives — 38,595 — 38,595 Total assets at fair value $ — $ 3,145,457 $ 71,013 $ 3,216,470 Derivative liabilities: Customer-initiated derivatives $ — $ 27,664 $ — $ 27,664 Forward contracts related to mortgage loans to be delivered for sale — 719 — 719 Power Equity CD — 718 — 718 Risk management derivatives — 3,278 — 3,278 Total derivatives — 32,379 — 32,379 Total liabilities at fair value $ — $ 32,379 $ — $ 32,379 There were no transfers between levels within the fair value hierarchy during the six months ended June 30, 2019 and 2018 . The following table summarizes the changes in Level 3 assets measured at fair value on a recurring basis. Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) Loan servicing rights Balance, beginning of period $ 64,701 $ 68,837 $ 71,013 $ 63,841 Gains (losses): Recorded in earnings (realized): Recorded in "Net gain on sale of loans and other mortgage banking revenue" (6,152 ) (757 ) (14,597 ) 2,272 New originations 2,109 2,284 4,242 4,251 Balance, end of period $ 60,658 $ 70,364 $ 60,658 $ 70,364 The Corporation has elected the fair value option for loans held-for-sale. These loans are intended for sale and the Corporation believes that the fair value is the best indicator of the resolution of these loans. Interest income is recorded based on the contractual terms of the loans in accordance with the Corporation's policy on loans held for investment in "Interest and fees on loans" in the Consolidated Statements of Income. There were no loans held-for-sale on nonaccrual status or 90 days past due and on accrual status as of June 30, 2019 and December 31, 2018 . The aggregate fair value, contractual balance (including accrued interest), and gain or loss for loans held-for-sale carried at fair value option was as follows: (Dollars in thousands) June 30, December 31, Aggregate fair value $ 33,019 $ 85,030 Contractual balance 31,799 82,080 Unrealized gain 1,220 2,950 The total amount of gains from loans held-for-sale included in the Consolidated Statements of Income was as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Interest income (1) $ 336 $ 445 $ 969 $ 821 Change in fair value (2) 345 484 (1,730 ) (216 ) Net gain on sales of loans (2) 5,388 4,023 11,538 5,531 Total included in earnings $ 6,069 $ 4,952 $ 10,777 $ 6,136 (1) Included in "Interest and fees on loans" in the Consolidated Statements of Income. (2) Included in "Net gain on sale of loans and other mortgage banking revenue" in the Consolidated Statements of Income. Assets and Liabilities Recorded at Fair Value on a Nonrecurring Basis Investment securities: Investment securities classified as held-to-maturity are recorded at fair value if the value is below amortized cost and the Corporation has determined that such unrealized loss is an other-than-temporary impairment. Fair value measurement is based upon quoted prices, if available. If quoted prices are not available, fair values are generally measured using independent pricing models or other model-based valuation techniques that include market inputs, such as benchmark yields, reported trades, broker dealer quotes, issuer spreads, two-sided markets, benchmark securities, bids, offers, reference data and industry and economic events. Impaired Loans: The Corporation does not record loans held for investment at fair value on a recurring basis. However, from time to time, a loan is considered impaired and an allocation of the allowance (valuation allowance) may be established or a portion of the loan is charged off. Loans for which it is probable that payment of interest and principal will not be made in accordance with the contractual terms of the loan agreement are considered impaired. The fair value of impaired loans is estimated using one of several methods, including the loan's observable market price, the fair value of the collateral or the present value of the expected future cash flows discounted at the loan's effective interest rate. Those impaired loans not requiring a valuation allowance represent loans for which the fair value of the expected repayments or collateral exceed the remaining carrying amount of such loans. Impaired loans where a valuation allowance is established or a portion of the loan is charged off based on the fair value of collateral are subject to nonrecurring fair value measurement and require classification in the fair value hierarchy. The Corporation records impaired loans as Level 3 valuations as there is generally no observable market price or management determines the fair value of the collateral is further impaired below the independent appraised value. When management determines the fair value of the collateral is further impaired below the appraised value, discounts ranging between 20% and 30% of the appraised value are used depending on the nature of the collateral and the age of the most recent appraisal. Goodwill: Goodwill is subject to impairment testing on an annual basis. The assessment of goodwill for impairment requires a significant degree of judgment. In the event the assessment indicates that it is more-likely-than-not that the fair value is less than the carrying value, the asset is considered impaired and recorded at fair value. Goodwill that is impaired and subject to nonrecurring fair value measurements is a Level 3 valuation. At June 30, 2019 and December 31, 2018 , no goodwill was impaired. Core deposit intangibles : Core deposit intangible assets are recorded at fair value when initially recorded. Subsequently, core deposit intangible assets are amortized primarily on an accelerated basis over periods ranging from ten to fifteen years and are subject to impairment testing whenever events or changes in circumstances indicate that the carrying amount exceeds the fair value of the asset. If core deposit intangible asset impairment is identified, the Corporation classifies the impaired core deposit intangible asset subject to nonrecurring fair value measurements as Level 3 valuations. At June 30, 2019 and December 31, 2018 , there was no impairment identified for core deposit intangible assets. Other real estate owned and repossessed assets : The carrying amounts for other real estate and repossessed assets are reported in the Consolidated Statements of Financial Position under "Interest receivable and other assets." Other real estate and repossessed assets include real estate and other types of assets repossessed by the Corporation. Other real estate and repossessed assets are recorded at the lower of cost or fair value upon the transfer of a loan to other real estate and repossessed assets and, subsequently, continue to be measured and carried at the lower of cost or fair value. Fair value is based upon independent market prices, appraised values of the property or management's estimation of the value of the property. The Corporation records other real estate and repossessed assets as Level 3 valuations as management generally determines that the fair value of the property is impaired below the appraised value. When management determines the fair value of the property is further impaired below appraised value, discounts ranging between 20% and 30% of the appraised value are used depending on the nature of the property and the age of the most recent appraisal. Disclosure of Nonrecurring Basis Fair Value Measurements Certain assets may be required to be measured at fair value on a nonrecurring basis. The carrying value of these assets represent end of period values, which approximate the fair value measurements that occurred on the various measurement dates during the period. For assets measured at fair value on a nonrecurring basis, quantitative disclosures about fair value measurements for each major category of assets follow: (Dollars in thousands) Significant Unobservable Inputs (Level 3) June 30, 2019 Impaired loans $ 76,186 Other real estate and repossessed assets 3,463 Total $ 79,649 December 31, 2018 Impaired loans $ 63,247 Other real estate and repossessed assets 883 Total $ 64,130 There were no liabilities recorded at fair value on a nonrecurring basis at either June 30, 2019 or December 31, 2018 . The following table presents additional information about the significant unobservable inputs used in the fair value measurement of financial assets measured on a nonrecurring basis that were categorized within the Level 3 of the fair value hierarchy: (Dollars in thousands) Fair Value at Valuation Technique Significant Unobservable Inputs Range Impaired loans $ 76,186 Appraisal of collateral Discount for type of collateral and age of appraisal 20%-30% Other real estate and repossessed assets 3,463 Appraisal of property Discount for type of property and age of appraisal 20%-30% Disclosures About Fair Value of Financial Instruments GAAP requires disclosures about the estimated fair value of the Corporation's financial instruments, including those financial assets and liabilities that are not measured and reported at fair value on a recurring or nonrecurring basis. The Corporation utilized the fair value hierarchy in computing the fair values of its financial instruments. In cases where quoted market prices were not available, the Corporation employed the exit-price notion, using unobservable inputs requiring management's judgment to estimate the fair values of its financial instruments, which is considered a Level 3 valuation. This Level 3 valuation is affected by the assumptions made and, accordingly, is not necessarily indicative of amounts that would be realized in a current market exchange. It is also the Corporation's general practice and intent to hold the majority of its financial instruments until maturity and, therefore, the Corporation does not expect to realize the estimated amounts disclosed. A summary of carrying amounts and estimated fair values of the Corporation's financial instruments not recorded at fair value in their entirety on a recurring basis on the Consolidated Statements of Financial Position are disclosed in the table below. Level in Fair Value Measurement Hierarchy June 30, 2019 December 31, 2018 (Dollars in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial assets: Investment securities: Held-to-maturity Level 2 $ 565,546 $ 575,042 $ 623,599 $ 618,232 Held-to-maturity Level 3 500 460 500 440 Net loans (1) Level 3 15,745,936 15,717,256 15,159,795 14,907,789 Financial liabilities: Time deposits Level 2 $ 4,360,014 $ 4,354,554 $ 4,074,248 $ 4,041,212 Collateralized customer deposits Level 2 291,671 291,513 382,687 382,370 Short-term borrowings Level 2 2,615,000 2,614,777 2,035,000 2,034,719 Long-term borrowings Level 2 426,069 431,043 426,002 423,258 (1) Included $76.2 million and $63.2 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2019 and December 31, 2018 , respectively. The short-term nature of certain assets and liabilities result in their carrying value approximating fair value. These include cash and cash equivalents, nonmarketable equity securities, interest receivable, bank owned life insurance, deposits without defined maturities and interest payable.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Investment Securities	Investment Securities The following is a summary of the amortized cost and fair value of investment securities carried at fair value and investment securities held-to-maturity at June 30, 2019 and December 31, 2018 : Investment Securities Carried at Fair Value (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2019 Debt securities Government and government-sponsored enterprises $ 297,284 $ 378 $ 1,936 $ 295,726 State and political subdivisions 428,365 15,845 125 444,085 Residential mortgage-backed securities 351,790 2,807 975 353,622 Collateralized mortgage obligations 1,930,699 14,869 5,873 1,939,695 Corporate bonds 291,869 1,337 3,894 289,312 Trust preferred securities 47,672 502 742 47,432 Total $ 3,347,679 $ 35,738 $ 13,545 $ 3,369,872 December 31, 2018 Debt securities Government and government-sponsored enterprises $ 354,342 $ 713 $ 3,355 $ 351,700 State and political subdivisions 523,178 1,141 8,033 516,286 Residential mortgage-backed securities 216,990 261 3,823 213,428 Collateralized mortgage obligations 1,623,415 2,903 25,020 1,601,298 Corporate bonds 304,243 259 11,439 293,063 Trust preferred securities 47,477 324 1,744 46,057 Total $ 3,069,645 $ 5,601 $ 53,414 $ 3,021,832 Investment Securities Held-to-Maturity (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2019 State and political subdivisions $ 565,546 $ 10,576 $ 1,080 $ 575,042 Trust preferred securities 500 — 40 460 Total $ 566,046 $ 10,576 $ 1,120 $ 575,502 December 31, 2018 State and political subdivisions $ 623,599 $ 2,548 $ 7,915 $ 618,232 Trust preferred securities 500 — 60 440 Total $ 624,099 $ 2,548 $ 7,975 $ 618,672 Investment securities are classified at the time they are acquired as either available-for-sale, held-to-maturity or carried at fair value based upon various factors, including asset/liability management strategies, liquidity and profitability objectives and regulatory requirements. Debt securities classified as available-for-sale are recorded at fair value. Investment securities carried at fair value may be sold prior to maturity based upon asset/liability management decisions. Unrealized gains or losses on available-for-sale debt securities are recorded as part of accumulated other comprehensive income in stockholders' equity. Held-to-maturity securities are carried at amortized cost, adjusted for amortization of premiums or accretion of discounts. The majority of the Corporation's residential mortgage-backed securities and collateralized mortgage obligations are backed by a U.S. government agency (Government National Mortgage Association) or a government sponsored enterprise (Federal Home Loan Mortgage Corporation or Federal National Mortgage Association). Proceeds from sales of investment securities carried at fair value and the associated gains and losses recorded in earnings are listed below: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Proceeds $ 133,829 $ 4,215 $ 205,331 $ 4,215 Gross gains 4,180 42 4,732 42 Gross losses (20 ) (39 ) (485 ) (39 ) The following is a summary of the amortized cost and fair value of investment securities at June 30, 2019 , by maturity, for both carried at fair value and held-to-maturity. The maturities of residential mortgage-backed securities and collateralized mortgage obligations are based on scheduled principal payments. The maturities of all other debt securities are based on final contractual maturity. June 30, 2019 (Dollars in thousands) Amortized Cost Fair Value Investment Securities Carried at Fair Value: Due in one year or less $ 779,977 $ 784,061 Due after one year through five years 1,292,316 1,297,464 Due after five years through ten years 812,375 809,765 Due after ten years 463,011 478,582 Total $ 3,347,679 $ 3,369,872 Investment Securities Held-to-Maturity: Due in one year or less $ 55,592 $ 55,657 Due after one year through five years 207,221 209,710 Due after five years through ten years 138,384 142,283 Due after ten years 164,849 167,852 Total $ 566,046 $ 575,502 Securities carried at fair value of $897.0 million and $1.05 billion were pledged at June 30, 2019 and December 31, 2018 , respectively, to secure borrowings and deposits. At June 30, 2019 and December 31, 2018 , there were no holdings of securities of any one issuer, other than the U.S. government and its agencies, in an amount greater than 10% of shareholders' equity. The following schedule summarizes information for debt securities both carried at fair value and held-to-maturity with gross unrealized losses at June 30, 2019 and December 31, 2018 , aggregated by category and length of time that individual securities have been in a continuous unrealized loss position. As of June 30, 2019 , the Corporation's securities portfolio consisted of 1,912 securities, 512 of which were in an unrealized loss position. Less Than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses June 30, 2019 Government and government-sponsored enterprises $ 38,077 $ 74 $ 171,701 $ 1,862 $ 209,778 $ 1,936 State and political subdivisions 10,105 15 242,873 1,190 252,978 1,205 Residential mortgage-backed securities 14,778 17 102,387 958 117,165 975 Collateralized mortgage obligations 229,853 1,684 464,641 4,189 694,494 5,873 Corporate bonds 52,131 269 113,659 3,625 165,790 3,894 Trust preferred securities 24,902 600 2,712 182 27,614 782 Total $ 369,846 $ 2,659 $ 1,097,973 $ 12,006 $ 1,467,819 $ 14,665 December 31, 2018 Government and government-sponsored enterprises $ 167,164 $ 1,672 $ 62,200 $ 1,683 $ 229,364 $ 3,355 State and political subdivisions 190,551 1,932 657,327 14,016 847,878 15,948 Residential mortgage-backed securities 20,679 85 123,757 3,738 144,436 3,823 Collateralized mortgage obligations 496,356 5,268 656,208 19,752 1,152,564 25,020 Corporate bonds 169,431 5,888 103,688 5,551 273,119 11,439 Trust preferred securities 34,623 1,640 2,725 164 37,348 1,804 Total $ 1,078,804 $ 16,485 $ 1,605,905 $ 44,904 $ 2,684,709 $ 61,389 An assessment is performed quarterly by the Corporation to determine whether unrealized losses in its debt securities portfolio are temporary or other-than-temporary by carefully considering all reasonably available information. The Corporation reviews factors such as financial statements, credit ratings, news releases and other pertinent information of the underlying issuer or company to make its determination. Management did not believe any individual unrealized loss on any debt security, as of June 30, 2019 , represented an other-than-temporary impairment ("OTTI") as the unrealized losses for these securities resulted primarily from changes in benchmark U.S. Treasury interest rates and not credit issues. Management believed that the unrealized losses on debt securities at June 30, 2019 were temporary in nature and due primarily to changes in interest rates and reduced market liquidity and not as a result of credit-related issues. At June 30, 2019 , the Corporation did not have the intent to sell any of its impaired debt securities and believed that it was more-likely-than-not that the Corporation will not have to sell any such debt securities before a full recovery of amortized cost. Accordingly, at June 30, 2019 , the Corporation believed the impairments in its debt securities portfolio were temporary in nature. However, there is no assurance that OTTI may not occur in the future.

Loans

Loans	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Loans	Loans Loan portfolio segments are defined as the level at which an entity develops and documents a systematic methodology to determine its allowance. The Corporation has two loan portfolio segments (commercial loans and consumer loans) that it uses in determining the allowance. Both quantitative and qualitative factors are used by management at the loan portfolio segment level in determining the adequacy of the allowance for the Corporation. Classes of loans are a disaggregation of an entity's loan portfolio segments. Classes of loans are defined as a group of loans which share similar initial measurement attributes, risk characteristics, and methods for monitoring and assessing credit risk. The Corporation has six classes of loans, which are set forth below. Commercial — Loans and lines of credit to varying types of businesses, including municipalities, school districts and nonprofit organizations, for the purpose of supporting working capital, operational needs and term financing of equipment. Repayment of such loans is generally provided through operating cash flows of the business. Commercial loans are predominately secured by equipment, inventory, accounts receivable, personal guarantees of the owner and other sources of repayment, although the Corporation may also secure commercial loans with real estate. Commercial real estate — Loans secured by real estate occupied by the borrower for ongoing operations (owner-occupied), non-owner occupied real estate leased to one or more tenants (non-owner occupied) and vacant land that has been acquired for investment or future land development (vacant land). Real estate construction and land development — Real estate construction loans represent secured loans for the construction of business properties. Real estate construction loans often convert to a commercial real estate loan at the completion of the construction period. Land development loans represent secured development loans made to borrowers for the purpose of infrastructure improvements to vacant land to create finished marketable residential and commercial lots/land. Most land development loans are originated with the intention that the loans will be paid through the sale of developed lots/land by the developers within twelve months of the completion date. Land development loans at June 30, 2019 and December 31, 2018 were primarily comprised of loans to develop residential properties. Residential mortgage — Loans secured by one - to four -family residential properties, generally with fixed interest rates for periods of fifteen years or less. The loan-to-value ratio at the time of origination is generally 80% or less. Residential mortgage loans with a loan-to-value ratio of more than 80% generally require private mortgage insurance. Consumer installment — Loans to consumers primarily for the purpose of acquiring automobiles, recreational vehicles and watercraft and comprised primarily of indirect loans purchased from dealers. These loans generally consist of relatively small amounts that are spread across many individual borrowers. Home equity — Loans and lines of credit whereby consumers utilize equity in their personal residence, generally through a second mortgage, as collateral to secure the loan. Loans held-for-sale, comprised of fixed-rate residential mortgage and construction loans, were $33.0 million at June 30, 2019 and $85.0 million at December 31, 2018 . The Corporation sold loans totaling $196.9 million and $392.7 million during the three and six months ended June 30, 2019 , respectively, and $202.1 million and $392.6 million during the three and six months ended June 30, 2018 , respectively. Commercial, commercial real estate, and real estate construction and land development loans are referred to as the Corporation's commercial loan portfolio, while residential mortgage, consumer installment and home equity loans are referred to as the Corporation's consumer loan portfolio. A summary of the Corporation's loans follows: (Dollars in thousands) Originated Acquired (1) Total Loans June 30, 2019 Commercial loan portfolio: Commercial $ 3,752,528 $ 595,357 $ 4,347,885 Commercial real estate: Owner-occupied 1,528,802 495,759 2,024,561 Non-owner occupied 2,056,531 716,146 2,772,677 Vacant land 37,155 12,807 49,962 Total commercial real estate 3,622,488 1,224,712 4,847,200 Real estate construction and land development 671,773 28,997 700,770 Subtotal 8,046,789 1,849,066 9,895,855 Consumer loan portfolio: Residential mortgage 2,722,019 944,594 3,666,613 Consumer installment 1,497,467 55,368 1,552,835 Home equity 604,835 141,765 746,600 Subtotal 4,824,321 1,141,727 5,966,048 Total loans (2) $ 12,871,110 $ 2,990,793 $ 15,861,903 December 31, 2018 Commercial loan portfolio: Commercial $ 3,287,087 $ 715,481 $ 4,002,568 Commercial real estate: Owner-occupied 1,513,532 546,025 2,059,557 Non-owner occupied 1,966,330 818,690 2,785,020 Vacant land 40,295 27,215 67,510 Total commercial real estate 3,520,157 1,391,930 4,912,087 Real estate construction and land development 566,726 30,486 597,212 Subtotal 7,373,970 2,137,897 9,511,867 Consumer loan portfolio: Residential mortgage 2,407,305 1,051,361 3,458,666 Consumer installment 1,451,352 69,722 1,521,074 Home equity 612,129 166,043 778,172 Subtotal 4,470,786 1,287,126 5,757,912 Total loans (2) $ 11,844,756 $ 3,425,023 $ 15,269,779 (1) Loans acquired in the Talmer, Lake Michigan, Monarch, Northwestern and OAK acquisitions were elected to be accounted for under ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality (ASC 310-30), by analogy. (2) Reported net of deferred costs totaling $27.2 million and $19.7 million at June 30, 2019 and December 31, 2018 , respectively. The Corporation acquired loans at fair value as of the acquisition date, which includes loans acquired in the acquisitions of Talmer Bancorp, Inc. ("Talmer"), Lake Michigan Financial Corporation ("Lake Michigan"), Monarch Community Bancorp, Inc. ("Monarch"), Northwestern Bancorp, Inc. ("Northwestern") and O.A.K. Financial Corporation ("OAK"). Loans acquired in each of these transactions ("Acquired Loans") were elected to be accounted for under ASC 310-30, by analogy, which recognizes the expected shortfall of expected future cash flows, as compared to the contractual amount due, as nonaccretable difference. Any excess of the net present value of expected future cash flows over the acquisition date fair value is recognized as the accretable discount, or accretable yield. The accretable yield is recognized over the expected remaining life of the acquired loans on a pool basis. In the event an acquired loan is renewed or extended, the loan continues to be accounted for as an acquired loan on a pool basis in accordance with ASC 310-30. Activity for the accretable yield, which includes contractually due expected cash flows for acquired loans that have been renewed or extended since the date of acquisition and continue to be accounted for in loan pools in accordance with ASC 310-30, follows: (Dollars in thousands) Talmer Lake Michigan Monarch North-western OAK Total Three Months Ended June 30, 2019 Balance at beginning of period $ 469,713 $ 68,995 $ 16,967 $ 38,644 $ 8,345 $ 602,664 Accretion recognized in interest income (36,730 ) (5,291 ) (852 ) (3,214 ) (1,334 ) (47,421 ) Net reclassification (to) from nonaccretable difference (1) 730 409 750 745 913 3,547 Balance at end of period $ 433,713 $ 64,113 $ 16,865 $ 36,175 $ 7,924 $ 558,790 Three Months Ended June 30, 2018 Balance at beginning of period $ 685,830 $ 90,156 $ 21,154 $ 55,400 $ 16,158 $ 868,698 Accretion recognized in interest income (42,136 ) (6,302 ) (962 ) (4,618 ) (2,882 ) (56,900 ) Net reclassification (to) from nonaccretable difference (1) (27,526 ) (3,412 ) (61 ) (1,051 ) 1,016 (31,034 ) Balance at end of period $ 616,168 $ 80,442 $ 20,131 $ 49,731 $ 14,292 $ 780,764 Six Months Ended June 30, 2019 Balance at beginning of period $ 505,332 $ 73,132 $ 17,832 $ 41,455 $ 9,574 $ 647,325 Accretion recognized in interest income (74,761 ) (10,842 ) (1,626 ) (6,634 ) (2,703 ) (96,566 ) Net reclassification (to) from nonaccretable difference (1) 3,142 1,823 659 1,354 1,053 8,031 Balance at end of period $ 433,713 $ 64,113 $ 16,865 $ 36,175 $ 7,924 $ 558,790 Six Months Ended June 30, 2018 Balance at beginning of period $ 731,353 $ 95,124 $ 22,496 $ 60,814 $ 17,110 $ 926,897 Accretion recognized in interest income (84,776 ) (13,060 ) (2,118 ) (9,522 ) (5,985 ) (115,461 ) Net reclassification (to) from nonaccretable difference (1) (30,409 ) (1,622 ) (247 ) (1,561 ) 3,167 (30,672 ) Balance at end of period $ 616,168 $ 80,442 $ 20,131 $ 49,731 $ 14,292 $ 780,764 (1) The net reclassification results from changes in expected cash flows of the acquired loans which may include increases in the amount of contractual principal and interest expected to be collected due to improvement in credit quality, increases in balances outstanding from advances, renewals, extensions and interest rates; as well as reductions in contractual principal and interest expected to be collected due to credit deterioration, payoffs, and decreases in interest rates. Credit Quality Monitoring The Corporation maintains loan policies and credit underwriting standards as part of the process of managing credit risk. These standards include making loans generally only within the Corporation's market areas. The Corporation's lending markets generally consist of communities throughout Michigan, Ohio and Northern Indiana. The Corporation, through Chemical Bank, has a commercial loan portfolio approval process involving underwriting and individual and group loan approval authorities to consider credit quality and loss exposure at loan origination. The loans in the Corporation's commercial loan portfolio are risk rated at origination based on the grading system set forth below. The approval authority of relationship managers is established based on experience levels, with credit decisions greater than $1.25 million requiring credit officer approval and credit decisions greater than $3.0 million requiring group loan authority approval, except for six executive and senior officers who have varying loan limits up to $8.0 million . With respect to the group loan authorities, Chemical Bank has various regional loan committees that meet weekly to consider loans ranging in amounts of $3.0 million to $7.0 million , and a senior loan committee, consisting of certain executive and senior officers, that meets weekly to consider loans ranging in amounts of $7.0 million up to Chemical Bank's internal lending limit, depending on risk rating and credit action required. Credit actions exceeding Chemical Bank's internal lending limit require the approval of the board of directors of Chemical Bank. The majority of the Corporation's consumer loan portfolio is comprised of secured loans that are relatively small. The Corporation's consumer loan portfolio has a centralized approval process which utilizes standardized underwriting criteria. The ongoing measurement of credit quality of the consumer loan portfolio is largely done on an exception basis. If payments are made on schedule, as agreed, then no further monitoring is performed. However, if delinquency occurs, the delinquent loans are turned over to the Corporation's collection department for resolution, resulting in repossession or foreclosure if payments are not brought current. Credit quality for the entire consumer loan portfolio is measured by the periodic delinquency rate, nonaccrual amounts and actual losses incurred. Loans in the commercial loan portfolio tend to be larger and more complex than those in the consumer loan portfolio, and therefore, are subject to more intensive monitoring. All loans in the commercial loan portfolio have an assigned relationship manager, and most borrowers provide periodic financial and operating information that allows the relationship managers to stay abreast of credit quality during the life of the loans. The risk ratings of loans in the commercial loan portfolio are reassessed at least annually, with loans below an acceptable risk rating reassessed more frequently and reviewed by various loan committees within the Corporation at least quarterly. The Corporation maintains a centralized independent loan review function that monitors the approval process and ongoing asset quality of the loan portfolio, including the accuracy of loan grades. The Corporation also maintains an independent appraisal review function that participates in the review of all appraisals obtained by the Corporation for loans in the commercial loan portfolio. Credit Quality Indicators Commercial Loan Portfolio Risk categories for the Corporation's commercial loan portfolio establish the credit quality of a borrower by measuring liquidity, debt capacity, coverage and payment behavior as shown in the borrower's financial statements. The risk categories also measure the quality of the borrower's management and the repayment support offered by any guarantors. Risk categories for the Corporation's commercial loan portfolio are described as follows: Pass: Includes all loans without weaknesses or potential weaknesses identified in the categories of special mention, substandard or doubtful. Special Mention: Loans with potential credit weakness or credit deficiency, which, if not corrected, pose an unwarranted financial risk that could weaken the loan by adversely impacting the future repayment ability of the borrower. Substandard: Loans with a well-defined weakness, or weaknesses, such as loans to borrowers who may be experiencing losses from operations or inadequate liquidity of a degree and duration that jeopardizes the orderly repayment of the loan. Substandard loans also are distinguished by the distinct possibility of loss in the future if these weaknesses are not corrected. Doubtful: Loans with all the characteristics of a loan classified as Substandard, with the added characteristic that credit weaknesses make collection in full highly questionable and improbable. The primary source of repayment is nonexistent and there is doubt as to the value of the secondary source of repayments. A doubtful asset has a high probability of total or substantial loss, but because of pending events that may strengthen the asset, its classification as loss is deferred. Loss: An asset classified as loss is considered uncollectible and of such little value that the continuance as a bankable asset is not warranted. This classification does not mean that an asset has absolutely no recovery or salvage value, but rather that it is not practical or desirable to defer writing off this basically worthless asset even through partial recovery may occur in the future. The following schedule presents the recorded investment of loans in the commercial loan portfolio by credit risk categories at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Pass Special Mention Substandard Doubtful Total June 30, 2019 Originated Portfolio: Commercial $ 3,513,993 $ 123,194 $ 108,373 $ 6,968 $ 3,752,528 Commercial real estate: Owner-occupied 1,452,031 25,913 50,697 161 1,528,802 Non-owner occupied 2,023,577 5,516 27,433 5 2,056,531 Vacant land 35,546 96 1,513 — 37,155 Total commercial real estate 3,511,154 31,525 79,643 166 3,622,488 Real estate construction and land development 664,122 3,612 4,039 — 671,773 Subtotal 7,689,269 158,331 192,055 7,134 8,046,789 Acquired Portfolio: Commercial 505,823 62,253 25,512 1,769 595,357 Commercial real estate: Owner-occupied 462,266 18,226 14,835 432 495,759 Non-owner occupied 655,602 43,147 17,382 15 716,146 Vacant land 12,614 193 — — 12,807 Total commercial real estate 1,130,482 61,566 32,217 447 1,224,712 Real estate construction and land development 28,715 42 240 — 28,997 Subtotal 1,665,020 123,861 57,969 2,216 1,849,066 Total $ 9,354,289 $ 282,192 $ 250,024 $ 9,350 $ 9,895,855 December 31, 2018 Originated Portfolio: Commercial $ 3,118,894 $ 87,222 $ 77,036 $ 3,935 $ 3,287,087 Commercial real estate: Owner-occupied 1,430,948 32,056 50,286 242 1,513,532 Non-owner occupied 1,901,822 39,416 25,092 — 1,966,330 Vacant land 36,499 — 3,741 55 40,295 Total commercial real estate 3,369,269 71,472 79,119 297 3,520,157 Real estate construction and land development 557,040 6,108 3,578 — 566,726 Subtotal 7,045,203 164,802 159,733 4,232 7,373,970 Acquired Portfolio: Commercial 655,883 36,809 22,773 16 715,481 Commercial real estate: Owner-occupied 500,072 28,909 17,033 11 546,025 Non-owner occupied 740,900 52,546 25,244 — 818,690 Vacant land 26,978 237 — — 27,215 Total commercial real estate 1,267,950 81,692 42,277 11 1,391,930 Real estate construction and land development 29,248 97 1,141 — 30,486 Subtotal 1,953,081 118,598 66,191 27 2,137,897 Total $ 8,998,284 $ 283,400 $ 225,924 $ 4,259 $ 9,511,867 Consumer Loan Portfolio The Corporation evaluates the credit quality of loans in the consumer loan portfolio based on the performing or nonperforming status of the loan. Loans in the consumer loan portfolio that are performing in accordance with original contractual terms and are less than 90 days past due and accruing interest are considered to be in a performing status, while those that are in nonaccrual status, contractually past due 90 days or more as to interest or principal payments, are considered to be in a nonperforming status. Loans accounted for under ASC 310-30, "Acquired loans", that are not performing in accordance with contractual terms are not reported as nonperforming because these loans are recorded in pools at their net realizable value based on the principal and interest the Corporation expects to collect on these loans. The following schedule presents the recorded investment of loans in the consumer loan portfolio based on loans in a performing status and loans in a nonperforming status at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Residential Mortgage Consumer Installment Home Equity Total Consumer June 30, 2019 Originated Loans: Performing $ 2,714,383 $ 1,496,056 $ 601,348 $ 4,811,787 Nonperforming 7,636 1,411 3,487 12,534 Subtotal 2,722,019 1,497,467 604,835 4,824,321 Acquired Loans 944,594 55,368 141,765 1,141,727 Total $ 3,666,613 $ 1,552,835 $ 746,600 $ 5,966,048 December 31, 2018 Originated Loans: Performing $ 2,399,317 $ 1,450,076 $ 608,525 $ 4,457,918 Nonperforming 7,988 1,276 3,604 12,868 Subtotal 2,407,305 1,451,352 612,129 4,470,786 Acquired Loans 1,051,361 69,722 166,043 1,287,126 Total $ 3,458,666 $ 1,521,074 $ 778,172 $ 5,757,912 Nonperforming Assets and Past Due Loans Nonperforming assets consist of loans for which the accrual of interest has been discontinued, other real estate owned acquired through acquisitions, other real estate owned obtained through foreclosure and other repossessed assets. Loans are considered past due or delinquent when the contractual principal or interest due in accordance with the terms of the loan agreement or any portion thereof remains unpaid after the due date of the scheduled payments. Loans outside of those accounted for under ASC 310-30 are classified as nonaccrual when, in the opinion of management, collection of principal or interest is doubtful. The accrual of interest is discontinued when a loan is placed in nonaccrual status and any payments received reduce the carrying value of the loan. A loan may be placed back on accrual status if all contractual payments have been received and collection of future principal and interest payments are no longer doubtful. Acquired loans that are not performing in accordance with contractual terms are not reported as nonperforming because these loans are recorded in pools at their net realizable value based on the principal and interest the Corporation expects to collect on these loans. A summary of nonperforming assets follows: (Dollars in thousands) June 30, December 31, Nonperforming assets Nonaccrual loans: Commercial $ 37,762 $ 30,139 Commercial real estate: Owner-occupied 20,814 16,056 Non-owner occupied 21,639 23,021 Vacant land 1,446 3,337 Total commercial real estate 43,899 42,414 Real estate construction and land development 3,501 12 Residential mortgage 7,636 7,988 Consumer installment 1,411 1,276 Home equity 3,487 3,604 Total nonaccrual loans 97,696 85,433 Other real estate owned and repossessed assets 8,267 6,256 Total nonperforming assets $ 105,963 $ 91,689 The Corporation's nonaccrual loans at June 30, 2019 and December 31, 2018 included $29.9 million and $28.1 million , respectively, of nonaccrual TDRs. The Corporation had $3.6 million of residential mortgage loans that were in the process of foreclosure at June 30, 2019 , compared to $4.5 million at December 31, 2018 . Loan delinquency, excluding acquired loans accounted for under ASC 310-30, was as follows: Loans Past Due and Still Accruing (Dollars in thousands) 30-89 days past due 90 days or more past due Total past due Nonaccrual Loans Current Total loans June 30, 2019 Originated Portfolio: Commercial $ 19,158 $ 146 $ 19,304 $ 37,762 $ 3,695,462 $ 3,752,528 Commercial real estate: Owner-occupied 3,368 — 3,368 20,814 1,504,620 1,528,802 Non-owner occupied 1,714 — 1,714 21,639 2,033,178 2,056,531 Vacant land 501 — 501 1,446 35,208 37,155 Total commercial real estate 5,583 — 5,583 43,899 3,573,006 3,622,488 Real estate construction and land development 538 — 538 3,501 667,734 671,773 Residential mortgage 6,183 — 6,183 7,636 2,708,200 2,722,019 Consumer installment 3,076 — 3,076 1,411 1,492,980 1,497,467 Home equity 2,557 — 2,557 3,487 598,791 604,835 Total $ 37,095 $ 146 $ 37,241 $ 97,696 $ 12,736,173 $ 12,871,110 December 31, 2018 Originated Portfolio: Commercial $ 16,835 $ — $ 16,835 $ 30,139 $ 3,240,113 $ 3,287,087 Commercial real estate: Owner-occupied 4,657 52 4,709 16,056 1,492,767 1,513,532 Non-owner occupied 1,793 887 2,680 23,021 1,940,629 1,966,330 Vacant land 160 — 160 3,337 36,798 40,295 Total commercial real estate 6,610 939 7,549 42,414 3,470,194 3,520,157 Real estate construction and land development 247 — 247 12 566,467 566,726 Residential mortgage 1,688 — 1,688 7,988 2,397,629 2,407,305 Consumer installment 4,731 — 4,731 1,276 1,445,345 1,451,352 Home equity 3,843 488 4,331 3,604 604,194 612,129 Total $ 33,954 $ 1,427 $ 35,381 $ 85,433 $ 11,723,942 $ 11,844,756 Impaired Loans A loan is impaired when, based on current information and events, it is probable that the Corporation will be unable to collect all amounts due according to the contractual terms of the loan agreement. Impaired loans include nonperforming loans and all TDRs. Impaired loans are accounted for at the lower of the present value of expected cash flows or the estimated fair value of the collateral. When the present value of expected cash flows or the fair value of the collateral of an impaired loan not accounted for under ASC 310-30 is less than the amount of unpaid principal outstanding on the loan, the recorded principal balance of the loan is reduced to its carrying value through either a specific allowance for loan loss or a partial charge-off of the loan balance. The following schedules present impaired loans by classes of loans at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Recorded investment Unpaid principal balance Related valuation allowance June 30, 2019 Impaired loans with a valuation allowance: Commercial $ 28,732 $ 31,556 $ 5,805 Commercial real estate: Owner-occupied 20,050 22,193 2,168 Non-owner occupied 18,080 19,966 1,366 Vacant land 786 1,003 59 Total commercial real estate 38,916 43,162 3,593 Real estate construction and land development 3,612 3,612 365 Residential mortgage 10,060 10,060 790 Consumer installment 1,594 1,594 109 Home equity 4,290 4,290 356 Subtotal 87,204 94,274 11,018 Impaired loans with no related valuation allowance: Commercial 28,775 29,586 — Commercial real estate: Owner-occupied 12,057 12,895 — Non-owner occupied 7,827 8,339 — Vacant land 776 1,704 — Total commercial real estate 20,660 22,938 — Real estate construction and land development 164 164 — Residential mortgage 7,235 7,235 — Consumer installment 7 7 — Home equity 1,656 1,656 — Subtotal 58,497 61,586 — Total impaired loans: Commercial 57,507 61,142 5,805 Commercial real estate: Owner-occupied 32,107 35,088 2,168 Non-owner occupied 25,907 28,305 1,366 Vacant land 1,562 2,707 59 Total commercial real estate 59,576 66,100 3,593 Real estate construction and land development 3,776 3,776 365 Residential mortgage 17,295 17,295 790 Consumer installment 1,601 1,601 109 Home equity 5,946 5,946 356 Total $ 145,701 $ 155,860 $ 11,018 (Dollars in thousands) Recorded Unpaid Related December 31, 2018 Impaired loans with a valuation allowance: Commercial $ 20,957 $ 23,781 $ 3,546 Commercial real estate: Owner-occupied 14,702 16,519 1,359 Non-owner occupied 16,833 17,452 462 Vacant land 1,008 1,208 96 Total commercial real estate 32,543 35,179 1,917 Real estate construction and land development 126 126 11 Residential mortgage 10,867 10,867 816 Consumer installment 1,126 1,126 186 Home equity 4,432 4,432 328 Subtotal 70,051 75,511 6,804 Impaired loans with no related valuation allowance: Commercial 25,093 25,934 — Commercial real estate: Owner-occupied 10,971 11,601 — Non-owner occupied 12,412 13,411 — Vacant land 2,825 3,911 — Total commercial real estate 26,208 28,923 — Real estate construction and land development 111 111 — Residential mortgage 7,537 7,537 — Consumer installment 377 377 — Home equity 1,496 1,496 — Subtotal 60,822 64,378 — Total impaired loans: Commercial 46,050 49,715 3,546 Commercial real estate: Owner-occupied 25,673 28,120 1,359 Non-owner occupied 29,245 30,863 462 Vacant land 3,833 5,119 96 Total commercial real estate 58,751 64,102 1,917 Real estate construction and land development 237 237 11 Residential mortgage 18,404 18,404 816 Consumer installment 1,503 1,503 186 Home equity 5,928 5,928 328 Total $ 130,873 $ 139,889 $ 6,804 The following schedule presents additional information regarding impaired loans by classes of loans segregated by those requiring a valuation allowance and those not requiring a valuation allowance for the three and six months ended June 30, 2019 and 2018 , and the respective interest income amounts recognized: Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (Dollars in thousands) Average recorded investment Interest income recognized while on impaired status Average recorded investment Interest income recognized while on impaired status Average Interest income Average Interest income Impaired loans with a valuation allowance: Commercial $ 26,587 $ 93 $ 18,139 $ 111 $ 24,109 $ 179 $ 19,271 $ 276 Commercial real estate: Owner-occupied 17,515 130 12,949 81 17,522 255 13,510 163 Non-owner occupied 9,050 9 2,246 10 11,055 54 3,058 21 Vacant land 788 2 1,308 17 896 10 2,502 32 Total commercial real estate 27,353 141 16,503 108 29,473 319 19,070 216 Real estate construction and land development 3,730 2 243 2 3,174 4 234 4 Residential mortgage 10,011 97 12,762 115 10,005 198 13,183 232 Consumer installment 1,250 2 1,067 2 1,213 4 986 3 Home equity 3,830 24 2,812 21 3,739 46 3,253 38 Subtotal 72,761 359 51,526 359 $ 71,713 $ 750 $ 55,997 $ 769 Impaired loans with no related valuation allowance: Commercial 27,865 201 20,078 147 $ 27,510 $ 384 $ 19,102 $ 242 Commercial real estate: Owner-occupied 14,110 73 14,565 81 12,841 126 14,967 137 Non-owner occupied 16,677 58 9,539 38 16,073 105 8,349 103 Vacant land 1,140 — 3,440 — 1,787 — 2,604 — Total commercial real estate 31,927 131 27,544 119 30,701 231 25,920 240 Real estate construction and land development 102 2 1,994 2 76 4 1,051 3 Residential mortgage 7,241 29 7,075 25 7,488 57 6,606 48 Consumer installment 36 — 41 — 226 — 91 — Home equity 1,987 5 2,487 2 2,096 12 2,266 9 Subtotal 69,158 368 59,219 295 $ 68,097 $ 688 $ 55,036 $ 542 Total impaired loans: Commercial 54,452 294 38,217 258 $ 51,619 $ 563 $ 38,373 $ 518 Commercial real estate: Owner-occupied 31,625 203 27,514 162 30,363 381 28,477 300 Non-owner occupied 25,727 67 11,785 48 27,128 159 11,407 124 Vacant land 1,928 2 4,748 17 2,683 10 5,106 32 Total commercial real estate 59,280 272 44,047 227 60,174 550 44,990 456 Real estate construction and land development 3,832 4 2,237 4 3,250 8 1,285 7 Residential mortgage 17,252 126 19,837 140 17,493 255 19,789 280 Consumer installment 1,286 2 1,108 2 1,439 4 1,077 3 Home equity 5,817 29 5,299 23 5,835 58 5,519 47 Total $ 141,919 $ 727 $ 110,745 $ 654 $ 139,810 $ 1,438 $ 111,033 $ 1,311 The difference between an impaired loan's recorded investment and the unpaid principal balance for originated loans represents a partial charge-off resulting from a confirmed loss due to the value of the collateral securing the loan being below the loan balance and management's assessment that full collection of the loan balance is not likely. Impaired loans included $47.9 million and $45.6 million at June 30, 2019 and December 31, 2018 , respectively, of accruing TDRs. Loans Modified Under Troubled Debt Restructurings (TDRs) The following tables present the recorded investment of loans modified into TDRs during the three and six months ended June 30, 2019 and 2018 by type of concession granted. In cases where more than one type of concession was granted, the loans were categorized based on the most significant concession. Concession type (Dollars in thousands) Principal Principal Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2019 Commercial loan portfolio: Commercial $ 14 $ 12 $ 426 $ 3,351 13 $ 3,818 $ 3,803 Commercial real estate: Owner-occupied 156 — 268 — 4 436 424 Non-owner occupied — — 140 — 1 154 140 Vacant land — — — 244 1 269 244 Total commercial real estate 156 — 408 244 6 859 808 Total commercial 170 12 834 3,595 19 4,677 4,611 Consumer loan portfolio: Residential mortgage 81 — 330 — 4 422 411 Consumer installment 15 39 13 — 6 70 67 Home equity 167 19 168 — 8 371 354 Total consumer 263 58 511 — 18 863 832 Total loans $ 433 $ 70 $ 1,345 $ 3,595 37 $ 5,540 $ 5,443 For the six months ended June 30, 2019 Commercial loan portfolio: Commercial $ 388 $ 12 $ 867 $ 6,892 24 $ 8,386 $ 8,159 Commercial real estate: Owner-occupied 2,863 103 297 1,360 9 4,649 4,623 Non-owner occupied — — 140 — 1 154 140 Vacant land 22 — — 244 2 293 266 Total commercial real estate 2,885 103 437 1,604 12 5,096 5,029 Total Commercial 3,273 115 1,304 8,496 36 13,482 13,188 Consumer loan portfolio: Residential mortgage 248 75 330 — 6 679 653 Consumer installment 61 65 13 — 17 149 139 Home equity 275 19 168 — 11 482 462 Total Consumer 584 159 511 — 34 1,310 1,254 Total loans $ 3,857 $ 274 $ 1,815 $ 8,496 70 $ 14,792 $ 14,442 Concession type (Dollars in thousands) Principal Principal Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2018 Commercial loan portfolio: Commercial $ 740 $ — $ 218 $ — 13 $ 969 $ 958 Commercial real estate: Owner-occupied 370 — 162 31 6 575 563 Total commercial real estate 370 — 162 31 6 575 563 Total commercial 1,110 — 380 31 19 1,544 1,521 Consumer loan portfolio: Residential mortgage 131 40 39 — 3 215 210 Consumer installment 15 44 10 — 9 72 69 Home equity 81 — 87 — 4 171 168 Total consumer 227 84 136 — 16 458 447 Total loans $ 1,337 $ 84 $ 516 $ 31 35 $ 2,002 $ 1,968 For the six months ended June 30, 2018 Commercial loan portfolio: Commercial $ 1,643 $ — $ 1,283 $ 261 31 $ 3,204 $ 3,187 Commercial real estate: Owner-occupied 370 — 888 513 8 1,783 1,771 Non-owner occupied 68 — — — 1 74 68 Total commercial real estate 438 — 888 513 9 1,857 1,839 Total Commercial 2,081 — 2,171 774 40 5,061 5,026 Consumer loan portfolio: Residential mortgage 269 40 39 — 7 357 348 Consumer installment 86 67 38 — 25 200 191 Home equity 266 — 115 — 9 424 381 Total Consumer 621 107 192 — 41 981 920 Total loans $ 2,702 $ 107 $ 2,363 $ 774 81 $ 6,042 $ 5,946 The pre-modification and post-modification recorded investment represents amounts as of the date of loan modification. The difference between the pre-modification and post-modification recorded investment of residential mortgage TDRs represents impairment recognized by the Corporation through the provision for loan losses computed based on a loan's post-modification present value of expected future cash flows discounted at the loan's original effective interest rate. The following schedule presents the Corporation's TDRs at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Accruing TDRs Nonaccrual TDRs Total Jun

Other Real Estate Owned and Rep

Other Real Estate Owned and Repossessed Assets	6 Months Ended
	Jun. 30, 2019
Other Real Estate [Abstract]
Other Real Estate Owned and Repossessed Assets	Other Real Estate Owned and Repossessed Assets Changes in other real estate owned and repossessed assets, included in interest receivable and other assets on the Consolidated Statements of Financial Position, were as follows: (Dollars in thousands) Other real estate Repossessed Balance at January 1, 2019 $ 5,832 $ 424 Additions (1) 5,420 1,309 Net payments received (214 ) — Disposals (2,372 ) (1,403 ) Write-downs (729 ) — Balance at June 30, 2019 $ 7,937 $ 330 Balance at January 1, 2018 $ 8,182 $ 625 Transfers based on adoption of ASU 2014-09 (2) (189 ) — Additions (1) 2,448 2,645 Net payments received (139 ) — Disposals (4,642 ) (2,319 ) Write-downs (783 ) — Balance at June 30, 2018 $ 4,877 $ 951 (1) Includes loans transferred to other real estate owned and other repossessed assets. (2) In accordance with the updates to Topic 606 adopted by the Corporation effective January 1, 2018, $1.1 million of other real estate owned sold with seller financing were reclassified on the Consolidated Statements of Financial Position to loans and the related $0.9 million of deferred gains were recognized in income as an adjustment to opening retained earnings. Refer to Note 1, Basis of Presentation and Significant Accounting Policies, for further information. At June 30, 2019 , the Corporation had $1.9 million of other real estate owned and repossessed assets as a result of obtaining physical possession in accordance with ASU No. 2014-04, Reclassification of Residential Real Estate Collateralized Consumer Mortgage Loans Upon Foreclosure. In addition, there were $3.6 million of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process as of June 30, 2019 . Income and expenses related to other real estate owned and repossessed assets, recorded as a component of "Other" operating expenses in the Consolidated Statements of Income, were as follows: (Dollars in thousands) Other real estate owned Repossessed assets For the three months ended June 30, 2019 Net gain (loss) on sale $ 824 $ (14 ) Write-downs (435 ) — Net operating expenses (248 ) (2 ) Total $ 141 $ (16 ) For the six months ended June 30, 2019 Net gain (loss) on sale $ 1,568 $ (32 ) Write-downs (729 ) — Net operating expenses (555 ) (5 ) Total $ 284 $ (37 ) For the three months ended June 30, 2018 Net gain (loss) on sale $ 23 $ (60 ) Write-downs (132 ) — Net operating expenses (318 ) (2 ) Total $ (427 ) $ (62 ) For the six months ended June 30, 2018 Net gain (loss) on sale $ 779 $ (94 ) Write-downs (783 ) — Net operating expenses (715 ) (3 ) Total $ (719 ) $ (97 )

Goodwill

Goodwill	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Goodwill was $1.13 billion at both June 30, 2019 and December 31, 2018 . The difference between consideration paid for the business and the net fair value of assets and liabilities is recognized as goodwill. Goodwill is not amortized but is subject to impairment testing annually as of October 31 and on an interim basis if events or changes in circumstances indicate assets might be impaired. Impairment exists when the carrying value of goodwill exceeds its fair value. The Corporation’s most recent annual goodwill impairment review performed as of October 31, 2018 did not indicate that an impairment of goodwill existed. The Corporation also determined that no triggering events have occurred that indicated impairment from the most recent valuation date through June 30, 2019 and that the Corporation's goodwill was no t impaired at June 30, 2019 .

Loan Servicing Rights

Loan Servicing Rights	6 Months Ended
	Jun. 30, 2019
Transfers and Servicing [Abstract]
Loan Servicing Rights	Loan Servicing Rights LSRs are created as a result of selling residential mortgage and commercial real estate loans in the secondary market while retaining the right to service these loans and receive servicing income over the life of the loan, and from acquisitions of other banks that had LSRs. Loans serviced for others are not reported as assets in the Consolidated Statements of Financial Position. The Corporation has elected to account for LSRs under the fair value measurement method. LSRs are established and recorded at the estimated fair value by calculating the present value of estimated future net servicing cash flows, taking into consideration actual and expected mortgage loan prepayment rates, discount rates, servicing costs, and other economic factors, which are determined based on current market conditions. The following table represents the activity for LSRs and the related fair value changes: (Dollars in thousands) Commercial Real Estate Mortgage Total For the three months ended June 30, 2019 Fair value, beginning of period $ 559 $ 64,142 $ 64,701 Additions from loans sold with servicing retained — 2,109 2,109 Changes in fair value due to: Reductions from pay-offs, pay downs and run-off (34 ) (661 ) (695 ) Changes in estimates of fair value (1) — (5,457 ) (5,457 ) Fair value, end of period $ 525 $ 60,133 $ 60,658 For the six months ended June 30, 2019 Fair value, beginning of period $ 451 $ 70,562 $ 71,013 Additions from loans sold with servicing retained 138 4,104 4,242 Changes in fair value due to: 0 0 Reductions from pay-offs, pay downs and run-off (64 ) (1,430 ) (1,494 ) Changes in estimates of fair value (1) — (13,103 ) (13,103 ) Fair value, end of period $ 525 $ 60,133 $ 60,658 Principal balance of loans serviced $ 43,657 $ 6,731,556 $ 6,775,213 For the three months ended June 30, 2018 Fair value, beginning of period $ 441 $ 68,396 $ 68,837 Additions from loans sold with servicing retained 45 2,239 2,284 Changes in fair value due to: 0 Reductions from pay-offs, pay downs and run-off (29 ) (698 ) (727 ) Changes in estimates of fair value (1) — (30 ) (30 ) Fair value, end of period $ 457 $ 69,907 $ 70,364 For the six months ended June 30, 2018 Fair value, beginning of period $ 427 $ 63,414 $ 63,841 Additions from loans sold with servicing retained 88 4,163 4,251 Changes in fair value due to: Reductions from pay-offs, pay downs and run-off (58 ) (1,392 ) (1,450 ) Change in estimates of fair value (1) — 3,722 3,722 Fair value, end of period $ 457 $ 69,907 $ 70,364 Principal balance of loans serviced $ 42,490 $ 6,946,356 $ 6,988,846 (1) Represents estimated LSR value change resulting primarily from market-driven changes in interest rates and prepayments. Included in "Net gain on sale of loans and other mortgage banking revenue" in the Consolidated Statements of Income. Expected and actual loan prepayment speeds are the most significant factors driving the fair value of loan servicing rights. The following table presents assumptions utilized in determining the fair value of loan servicing rights as of June 30, 2019 and December 31, 2018 . Mortgage As of June 30, 2019 Prepayment speed 6.0 - 29.72 Weighted average ("WA") discount rate 10.1 % WA cost to service/per year $ 66 WA ancillary income/per year $ 31 WA float range 2.4 % As of December 31, 2018 Prepayment speed 0.0 - 26.4% WA discount rate 10.1 % WA cost to service/per year $ 66 WA ancillary income/per year $ 31 WA float range 2.5 % The Corporation realized total loan servicing fee income of $4.2 million and $4.4 million for the three months ended June 30, 2019 and 2018 , respectively, and $8.4 million and $9.0 million for the six months ended June 30, 2019 and 2018 , respectively, included in "Net gain on sale of loans and other mortgage banking revenue" in the Consolidated Statements of Income.

Core Deposit Intangibles

Core Deposit Intangibles	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Core Deposit Intangibles	Core Deposit Intangibles The Corporation recorded core deposit intangible assets associated with each of its acquisitions and its merger with Talmer. Core deposit intangible assets are amortized on an accelerated basis over their estimated useful lives and have an estimated remaining weighted-average useful life of 6.1 years as of June 30, 2019 . The following table sets forth the carrying amount and accumulated amortization of core deposit intangible assets that are amortizable and arose from business combinations or other acquisitions: (Dollars in thousands) June 30, December 31, Gross original amount $ 56,456 $ 56,456 Accumulated amortization 30,621 27,900 Net carrying amount $ 25,835 $ 28,556 Amortization expense recognized on core deposit intangible assets was $1.4 million for both the three months ended June 30, 2019 and 2018 , and $2.7 million and $2.9 million for the six months ended June 30, 2019 and 2018 , respectively. The estimated future amortization expense on core deposit intangible assets for periods ending after June 30, 2019 is as follows: (Dollars in thousands) Estimated amortization expense 2019 2,722 2020 4,851 2021 4,471 2022 4,218 2023 3,591 2024 and thereafter 5,982

Derivative Instruments and Bala

Derivative Instruments and Balance Sheet Offsetting	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Balance Sheet Offsetting	Derivative Instruments and Balance Sheet Offsetting In the normal course of business, the Corporation enters into various transactions involving derivative instruments to manage exposure to fluctuations in interest rates and to meet the financing needs of customers (customer-initiated derivatives). These financial instruments involve, to varying degrees, elements of market and credit risk. Market and credit risk are included in the determination of fair value. Commitments to fund mortgage loans (interest rate locks) to be sold into the secondary market and forward commitments for the future delivery of mortgage loans to third party investors are considered derivatives. It is the Corporation’s practice to enter into forward commitments for the future delivery of mortgage loans when interest rate lock commitments are entered into in order to economically hedge the effect of changes in interest rates resulting from its commitments to fund the loans. The Corporation enters into interest rate derivatives to provide a service to certain qualifying customers to help facilitate their respective risk management strategies. These customer-initiated derivatives are not used for interest rate risk management purposes and primarily consist of interest rate swaps, interest rate caps and floors and foreign exchange contracts. The Corporation generally takes offsetting positions with dealer counterparts to mitigate the inherent risk. Income primarily results from the spread between the customer derivative and the offsetting dealer positions. Gains and losses on customer-related derivatives are included in other noninterest income. The Corporation utilizes interest rate swaps designated as cash flow hedges for risk management purposes to manage exposure that arises from business activities that result in the receipt or payment of future known and uncertain cash amounts, the value of which are determined by interest rates. These interest rate swaps designated as cash flow hedges are used to manage differences in the amount, timing and duration of the Corporation's known or expected cash receipts and its known or expected cash payments principally related to certain variable rate borrowings. The Corporation assesses the effectiveness of each hedging relationship by comparing the changes in cash flows of the derivative instruments with the changes in cash flows of the designated hedged transactions. The changes in fair value of derivatives designated and that qualify as cash flow hedges are recorded in accumulated other comprehensive income (loss) and are subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. For the Corporation's derivative instruments that are designated and qualify as a cash flow hedge, the gain or loss on the derivative instrument, as well as the offsetting loss or gain on the hedged item attributable to the hedged risk are recognized in current earnings in the same line item as the offsetting loss or gain on the related interest rate swap. The Corporation expects the hedges to remain highly effective during the remaining terms of the swaps. The Corporation additionally has written and purchased option derivatives consisting of instruments to facilitate an equity-linked time deposit product (the "Power Equity CD"). The Power Equity CD is a time deposit that provides the purchaser a guaranteed return of principal at maturity plus a potential equity return (a written option), while the Corporation receives a known stream of funds based on the equity return (a purchased option). The written and purchased options are mirror derivative instruments which are carried at fair value on the Consolidated Statements of Financial Position. The following table presents the notional amount and fair value of the Corporation’s derivative instruments held or issued in connection with customer-initiated and mortgage banking activities. June 30, 2019 December 31, 2018 Fair Value Fair Value (Dollars in thousands) Notional Amount (1) Gross Derivative Assets (2) Gross Derivative Liabilities (2) Notional Amount (1) Gross Derivative Assets (2) Gross Derivative Liabilities (2) Risk management purposes: Derivatives designated as hedging instruments: Interest rate swaps $ 1,145,000 $ 606 $ 25,060 $ 820,000 $ 10,148 $ 3,278 Total risk management purposes 1,145,000 606 25,060 820,000 10,148 3,278 Customer-initiated and mortgage banking derivatives: Customer-initiated derivatives 2,908,127 69,024 70,707 2,477,640 26,680 27,664 Forward contracts related to mortgage loans to be delivered for sale 165,772 — 661 127,159 — 719 Interest rate lock commitments 149,084 2,687 — 54,848 1,049 — Power Equity CD 35,295 751 751 36,771 718 718 Total customer-initiated and mortgage banking derivatives 3,258,278 72,462 72,119 2,696,418 28,447 29,101 Total gross derivatives $ 4,403,278 $ 73,068 $ 97,179 $ 3,516,418 $ 38,595 $ 32,379 (1) Notional or contract amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Statements of Financial Position. (2) Derivative assets are included within "Interest receivable and other assets" and derivative liabilities are included within "Interest payable and other liabilities" on the Consolidated Statements of Financial Position. Included in the fair value of the derivative assets are credit valuation adjustments for counterparty credit risk totaling $1.5 million at June 30, 2019 and $901 thousand at December 31, 2018 . In the normal course of business, the Corporation may decide to settle a forward contract rather than fulfill the contract. Cash received or paid in this settlement manner is included in "Net gain on sale of loans and other mortgage banking revenue" in the Consolidated Statements of Income and is considered a cost of executing a forward contract. The following table presents the net gains (losses) related to derivative instruments reflecting the changes in fair value. Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) Location of Gain (Loss) 2019 2018 2019 2018 Forward contracts related to mortgage loans to be delivered for sale Net gain on sale of loans and other mortgage banking revenue $ (8 ) $ (21 ) $ 58 $ (391 ) Interest rate lock commitments Net gain on sale of loans and other mortgage banking revenue 929 211 1,638 763 Power Equity CD Other noninterest income — — — — Customer-initiated derivatives Other noninterest income (409 ) 39 (699 ) 366 Total gain (loss) recognized in income $ 512 $ 229 $ 997 $ 738 The following table presents the net gains (losses) recorded in accumulated other comprehensive income and the Consolidated Statements of Income relating to interest rate swaps designated as cash flow hedges for the three and six months ended June 30, 2019 and 2018 . (Dollars in thousands) Amount of gain (loss) recognized in other comprehensive income Amount of gain (loss) reclassified from other comprehensive income to interest income or expense Three Months Ended June 30, 2019 Interest rate swaps designated as cash flow hedges $ (21,229 ) $ 1,256 Three Months Ended June 30, 2018 Interest rate swaps designated as cash flow hedges 4,102 589 Six Months Ended June 30, 2019 Interest rate swaps designated as cash flow hedges $ (28,781 ) $ 2,544 Six Months Ended June 30, 2018 Interest rate swaps designated as cash flow hedges 12,065 347 At June 30, 2019 , the Corporation expected $2.2 million of unrealized gains to be reclassified as an increase to interest expense during the following twelve months. Methods and assumptions used by the Corporation in estimating the fair value of its forward contracts, interest rate lock commitments and customer-initiated derivatives are discussed in Note 3 , Fair Value Measurements. Balance Sheet Offsetting Certain financial instruments, including customer-initiated derivatives and interest rate swaps, may be eligible for offset in the Consolidated Statements of Financial Position and/or subject to master netting arrangements or similar agreements. The Corporation is party to master netting arrangements with its financial institution counterparties; however, the Corporation does not offset assets and liabilities under these arrangements for financial statement presentation purposes based on an accounting policy election. The tables below present information about the Corporation’s financial instruments that are eligible for offset. Gross amounts not offset in the statements of financial position (Dollars in thousands) Gross Gross amounts offset in the statements of financial condition Net amounts presented in the statements of financial position Financial Collateral Net June 30, 2019 Offsetting derivative assets Derivative assets (1) $ 69,553 $ — $ 69,553 $ — $ — $ 69,553 Offsetting derivative liabilities Derivative liabilities (1) 95,492 — 95,492 — 37,291 58,201 December 31, 2018 Offsetting derivative assets Derivative assets (1) $ 36,791 $ — $ 36,791 $ — $ (16,120 ) $ 20,671 Offsetting derivative liabilities Derivative liabilities 30,822 — 30,822 — 430 30,392 (1) Amount does not include participated interest rate swaps, forward contracts, interest rate lock commitments and power equity CDs as these instruments are not subject to master netting or similar arrangements.

Investments in Qualified Afford

Investments in Qualified Affordable Housing Projects, Federal Historic Projects and New Market Tax Credits	6 Months Ended
	Jun. 30, 2019
Equity Method Investments and Joint Ventures [Abstract]
Investments in Qualified Affordable Housing Projects, Federal Historic Projects and New Market Tax Credits	Investments in Qualified Affordable Housing Projects, Federal Historic Projects and New Market Tax Credits The Corporation invests in qualified affordable housing projects, federal historic projects, and new market projects for the purpose of community reinvestment and obtaining tax credits. Return on the Corporation's investment in these projects comes in the form of the tax credits and tax losses that pass through to the Corporation. The carrying value of the investments is reflected in "Interest receivable and other assets" on the Consolidated Statements of Financial Position. The Corporation utilizes the proportional amortization method to account for investments in qualified affordable housing projects and the equity method to account for investments in other tax credit projects. Under the proportional amortization method, the Corporation amortizes the initial cost of the investment in proportion to the tax credits and other tax benefits. The Corporation recognized additional income tax expense attributable to the amortization of investments in qualified affordable housing projects of $1.6 million and $1.1 million during the three months ended June 30, 2019 and 2018 , respectively, and $3.3 million and $2.1 million during the six months ended June 30, 2019 and 2018 , respectively. The Corporation's remaining investment in qualified affordable housing projects accounted for under the proportional amortization method totaled $85.8 million at June 30, 2019 and $84.9 million at December 31, 2018 . Under the equity method, the Corporation's share of the earnings or losses is included in "Other" operating expenses on the Consolidated Statements of Income. The Corporation's remaining investment in federal historic tax projects accounted for under the equity method totaled $32.1 million and $13.3 million at June 30, 2019 and December 31, 2018 , respectively. The Corporation's unfunded equity contributions relating to investments in qualified affordable housing projects, federal historic tax projects and new market projects is recorded in "Interest payable and other liabilities" on the Consolidated Statements of Financial Position. The Corporation's remaining unfunded equity contributions totaled $73.4 million and $72.0 million at June 30, 2019 and December 31, 2018 , respectively. Management analyzes these investments for potential impairment when events or changes in circumstances indicate that it is more-likely-than-not that the carrying amount of the investment will not be realized. An impairment loss is measured as the amount by which the carrying amount of an investment exceeds its fair value. During the three and six months ended June 30, 2019 , federal historic tax credits resulted in an income tax benefit of $260 thousand , partially offset by impairment expense of $271 thousand , representing $214 thousand net of tax, recorded in "Other" operating expense. During the three months ended June 30, 2018 , federal historic tax credits resulted in an income tax benefit of $1.9 million , partially offset by impairment expense of $1.7 million , representing $1.4 million net of tax, recorded in "Other" operating expense. During the six months ended June 30, 2018 , federal historic tax credits were placed into service resulting in an income tax benefit of $3.4 million , partially offset by impairment expense of $3.4 million , representing $2.6 million net of tax, recorded in "Other" operating expense. The Corporation consolidates variable interest entities ("VIEs") in which it is the primary beneficiary. In general, a VIE is an entity that either (i) has an insufficient amount of equity to carry out its principal activities without additional subordinated financial support, (ii) has a group of equity owners that are unable to make significant decisions about its activities or (iii) has a group of equity owners that do not have the obligation to absorb losses or the right to receive returns as generated by its operations. If any of these characteristics are present, the entity is subject to a variable interest consolidation model, and consolidation is based on variable interests, not on ownership of the entity's outstanding voting stock. Variable interests are defined as contractual, ownership, or other monetary interests in an entity that change with fluctuations in the entity's net asset value. The primary beneficiary consolidates the VIE. The primary beneficiary is defined as the enterprise that has the power to direct the activities and absorb losses or the right to receive benefits. The Corporation is a significant limited partner in the qualified affo rdable housing, federal historic and new market projects it has invested in . These projects meet the definition of VIEs. However, the Corporation is not the primary beneficiary of any of the VIEs in which it holds a limited partnership interest; therefore, the VIEs are not consolidated in the Consolidated Financial Statements.

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Leases	Leases On January 1, 2019, the Corporation adopted ASU 2016-02-Leases (Topic 842) and all subsequent ASUs that modified Topic 842. Refer to Note 1 , Basis of Presentation and Significant Accounting Policies, for further details regarding the adoption. Lessee Leases Operating leases in which the Corporation is the lessee are recorded as operating lease right-of-use ("ROU") assets and operating lease liabilities, included in "Interest receivable and other assets" and "Interest payable and other liabilities," respectively, in the Consolidated Statements of Financial Position. Operating lease ROU assets and operating lease liabilities are recognized at lease commencement based on the present value of the future minimum lease payments over the lease term. The Corporation has lease agreements with lease and non-lease components, which are accounted for separately. Where an implicit rate is not provided or determinable in the lease, the Corporation uses its incremental borrowing rate as a discount rate, on a collateralized basis, over a similar term. The lease term considers options to extend or terminate the lease when it is reasonably certain that the Corporation will exercise that option. The Corporation's leases relate primarily to real estate property consisting of branches, office space, storage and operation centers with remaining lease terms of generally 1 to 15 years. Certain lease arrangements contain extension options which typically range from 3 to 5 years. During the three and six months ended June 30, 2019, the Corporation obtained $877 thousand and $6.7 million of ROU assets in exchange for new lease liabilities. Cash paid for amounts included in the measurement of lease liabilities from operating leases were $2.0 million and $4.0 million for the three and six months ended June 30, 2019 . As of June 30, 2019 , operating lease ROU assets and liabilities were $40.5 million and $41.4 million , respectively. The following table presents balances and assumptions utilized in determining the right to use asset and lease liability for operating leases as of June 30, 2019 : June 30, 2019 Weighted-average remaining lease terms (in years) 7.85 Weighted-average discount rate 3.1 % The components of net operating lease cost were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2019 Operating lease cost $ 2,050 3,964 Variable lease cost (1) 247 454 Sublease income (56 ) (111 ) Total lease cost (2) $ 2,241 $ 4,307 (1) Represents non-lease components such as common area maintenance, taxes, insurance and utilities. (2) Included within "Occupancy" expense in the Consolidated Statements of Income. Maturities of operating lease liability due under these lease arrangements as of June 30, 2019 are as follows: (Dollars in thousands) Operating Leases Remainder of 2019 $ 4,081 2020 7,490 2021 7,083 2022 6,149 2023 5,017 Thereafter 17,041 Total $ 46,861 Less: Present value discount 5,458 Lease liability $ 41,403 As of June 30, 2019 , the Corporation has approximately $247.4 million in additional leases for real property that have not yet commenced and are excluded from the lessee maturity table above. Of the aforementioned amount, $231.6 million is related to a lease agreement for the new headquarters building in Detroit, Michigan signed on May 31, 2019, with an organization 50% owned by indirect related parties. The new headquarter lease will have a term of 22.5 years and a rent commencement date of January 1, 2022 with renewal options. At December 31, 2018 , operating lease commitments under lessee arrangements were $7.3 million , $6.2 million , $5.1 million , $4.8 million and $4.4 million for 2019 through 2023, respectively, and $12.1 million in aggregate for all years thereafter. These amounts include variable lease payments under leases that have not yet commenced, which are excluded from the lessee maturity analysis presented in the table above. Lessor Leases The Corporation is the lessor in certain arrangements, primarily for the use of real estate property. Lease agreements may include options to renew, but do not offer the right to purchase the underlying asset at the end of the lease term. Of the $123.7 million of net premises and equipment, $15.1 million represents underlying assets under operating leases as of June 30, 2019 . The components of operating lease income were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2019 Lease income - operating leases $ 169 363 Total lease income (1) $ 169 $ 363 (1) Included within "Other" noninterest income in the Consolidated Statements of Income.
Leases	Leases On January 1, 2019, the Corporation adopted ASU 2016-02-Leases (Topic 842) and all subsequent ASUs that modified Topic 842. Refer to Note 1 , Basis of Presentation and Significant Accounting Policies, for further details regarding the adoption. Lessee Leases Operating leases in which the Corporation is the lessee are recorded as operating lease right-of-use ("ROU") assets and operating lease liabilities, included in "Interest receivable and other assets" and "Interest payable and other liabilities," respectively, in the Consolidated Statements of Financial Position. Operating lease ROU assets and operating lease liabilities are recognized at lease commencement based on the present value of the future minimum lease payments over the lease term. The Corporation has lease agreements with lease and non-lease components, which are accounted for separately. Where an implicit rate is not provided or determinable in the lease, the Corporation uses its incremental borrowing rate as a discount rate, on a collateralized basis, over a similar term. The lease term considers options to extend or terminate the lease when it is reasonably certain that the Corporation will exercise that option. The Corporation's leases relate primarily to real estate property consisting of branches, office space, storage and operation centers with remaining lease terms of generally 1 to 15 years. Certain lease arrangements contain extension options which typically range from 3 to 5 years. During the three and six months ended June 30, 2019, the Corporation obtained $877 thousand and $6.7 million of ROU assets in exchange for new lease liabilities. Cash paid for amounts included in the measurement of lease liabilities from operating leases were $2.0 million and $4.0 million for the three and six months ended June 30, 2019 . As of June 30, 2019 , operating lease ROU assets and liabilities were $40.5 million and $41.4 million , respectively. The following table presents balances and assumptions utilized in determining the right to use asset and lease liability for operating leases as of June 30, 2019 : June 30, 2019 Weighted-average remaining lease terms (in years) 7.85 Weighted-average discount rate 3.1 % The components of net operating lease cost were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2019 Operating lease cost $ 2,050 3,964 Variable lease cost (1) 247 454 Sublease income (56 ) (111 ) Total lease cost (2) $ 2,241 $ 4,307 (1) Represents non-lease components such as common area maintenance, taxes, insurance and utilities. (2) Included within "Occupancy" expense in the Consolidated Statements of Income. Maturities of operating lease liability due under these lease arrangements as of June 30, 2019 are as follows: (Dollars in thousands) Operating Leases Remainder of 2019 $ 4,081 2020 7,490 2021 7,083 2022 6,149 2023 5,017 Thereafter 17,041 Total $ 46,861 Less: Present value discount 5,458 Lease liability $ 41,403 As of June 30, 2019 , the Corporation has approximately $247.4 million in additional leases for real property that have not yet commenced and are excluded from the lessee maturity table above. Of the aforementioned amount, $231.6 million is related to a lease agreement for the new headquarters building in Detroit, Michigan signed on May 31, 2019, with an organization 50% owned by indirect related parties. The new headquarter lease will have a term of 22.5 years and a rent commencement date of January 1, 2022 with renewal options. At December 31, 2018 , operating lease commitments under lessee arrangements were $7.3 million , $6.2 million , $5.1 million , $4.8 million and $4.4 million for 2019 through 2023, respectively, and $12.1 million in aggregate for all years thereafter. These amounts include variable lease payments under leases that have not yet commenced, which are excluded from the lessee maturity analysis presented in the table above. Lessor Leases The Corporation is the lessor in certain arrangements, primarily for the use of real estate property. Lease agreements may include options to renew, but do not offer the right to purchase the underlying asset at the end of the lease term. Of the $123.7 million of net premises and equipment, $15.1 million represents underlying assets under operating leases as of June 30, 2019 . The components of operating lease income were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2019 Lease income - operating leases $ 169 363 Total lease income (1) $ 169 $ 363 (1) Included within "Other" noninterest income in the Consolidated Statements of Income.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments, Contingencies and Guarantees	Commitments, Contingencies and Guarantees Commitments In the normal course of business, the Corporation offers a variety of financial instruments containing credit risk that are not required to be reflected in the Consolidated Statements of Financial Position. These financial instruments include outstanding commitments to extend credit, approved but undisbursed loans (undisbursed loan commitments), credit lines, commercial letters of credit and standby letters of credit. The Corporation has risk management policies to identify, monitor and limit exposure to credit risk. To mitigate credit risk for these financial guarantees, the Corporation generally determines the need for specific covenant, guarantee and collateral requirements on a case-by-case basis, depending on the nature of the financial instrument and the customer's creditworthiness. At June 30, 2019 and December 31, 2018 , the Corporation had $123.7 million and $119.0 million , respectively, of outstanding financial and performance standby letters of credit. The majority of these standby letters of credit are collateralized. At June 30, 2019 , the Corporation had determined that there was $329 thousand of potential losses from standby letters of credit at June 30, 2019 , compared to no potential losses at December 31, 2018 . Commitments to extend credit are agreements to lend to a customer provided there is no violation of any condition established in the commitment. Commitments generally have fixed expiration dates or other termination clauses and may not require payment of a fee. Since many commitments expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. The Corporation evaluates each customer's creditworthiness on an individual basis. The amount of collateral obtained, if deemed necessary by the Corporation upon extension of credit, is based on management's credit evaluation of the counterparty. The collateral held varies, but may include securities, real estate, accounts receivable, inventory, plant or equipment. Unfunded commitments under commercial lines of credit, revolving credit lines and overdraft protection agreements are included in commitments to extend credit. These lines of credit are generally not collateralized, usually do not contain a specified maturity date and may be drawn upon only to the total extent to which the Corporation is committed. At June 30, 2019 and December 31, 2018 , the Corporation had $3.82 billion and $3.55 billion , respectively, of commitments to extend credit. The Corporation had undisbursed loan commitments of $537.6 million and $493.3 million at June 30, 2019 and December 31, 2018 , respectively. Undisbursed loan commitments are not included in loans on the Consolidated Statements of Financial Position. The majority of undisbursed loan commitments will be funded and convert to a portfolio loan within a one year period. The allowance for credit losses on lending-related commitments included $1.9 million and $1.7 million at June 30, 2019 and December 31, 2018 , respectively, for probable credit losses inherent in the Corporation's unused commitments and was recorded in "Interest payable and other liabilities" in the Consolidated Statements of Financial Position. Contingencies and Guarantees The Corporation has originated and sold certain loans, and additionally acquired the potential liability for those historical originated and sold loans by merged or acquired entities, for which the buyer has limited recourse to us in the event the loans do not perform as specified in the agreements. These loans had an outstanding balance of $12.8 million and $11.6 million at June 30, 2019 and December 31, 2018 , respectively. The maximum potential amount of undiscounted future payments that the Corporation could be required to make in the event of nonperformance by the borrower totaled $12.6 million and $11.4 million at June 30, 2019 and December 31, 2018 , respectively. In the event of nonperformance, the Corporation has rights to the underlying collateral securing the loans. At both June 30, 2019 and December 31, 2018 , the Corporation had recorded a liability of $100 thousand , in connection with the recourse agreements, recorded in "Interest payable and other liabilities" in the Consolidated Statements of Financial Position. In addition, the Corporation acquired certain SBA guaranteed notes in which the guaranteed portion had been sold to a third party investor prior to the Corporation's acquisition. In the event these loans default and the SBA guaranty is no longer intact (i.e. an issue found to have occurred during the origination or the liquidation of the loans) the Corporation would be liable to make the loan whole to the third party investor. The maximum potential amount of undiscounted future payments that the Corporation could be required to make in the event of default by the borrower totaled $17.9 million and $19.1 million at June 30, 2019 and December 31, 2018 , respectively. In the event of default, the Corporation has rights to the underlying collateral securing the loans. At June 30, 2019 and December 31, 2018 , the Corporation had recorded a liability of $891 thousand and $1.2 million , respectively. Representations and Warranties In connection with the Corporation's mortgage banking loan sales, and the historical sales of merged or acquired entities, the Corporation makes certain representations and warranties that the loans meet certain criteria, such as collateral type and underwriting standards. The Corporation may be required to repurchase individual loans and/or indemnify the purchaser against losses if the loan fails to meet established criteria. At June 30, 2019 and December 31, 2018 , the liability recorded in connection with these representations and warranties totaled $3.2 million and $4.1 million , respectively. A summary of the reserve for representations and warranties of the Corporation is as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Reserve balance at beginning of period $ 3,983 $ 5,105 $ 4,084 $ 5,349 Reserve reduction (807 ) (243 ) (908 ) (487 ) Charge-offs — (2 ) — (2 ) Ending reserve balance $ 3,176 $ 4,860 $ 3,176 $ 4,860 (Dollars in thousands) June 30, 2019 December 31, 2018 Reserve balance Liability for specific claims $ 454 $ 398 General allowance 2,722 3,686 Total reserve balance $ 3,176 $ 4,084

Borrowings and Other Short-Term

Borrowings and Other Short-Term Liabilities	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Borrowings and Other Short-Term Liabilities	Borrowings and Other Short-Term Liabilities A summary of the Corporation's short- and long-term borrowings, and other short-term liabilities follows: June 30, 2019 December 31, 2018 (Dollars in thousands) Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Short-term borrowings: FHLB advances: 2.29% - 2.60% fixed-rate notes $ 2,580,000 2.44 % $ 2,035,000 2.47 % AFX short-term borrowings 35,000 2.41 — — Total short-term borrowings $ 2,615,000 2.44 % $ 2,035,000 2.47 % Long-term borrowings: FHLB advances: 1.00% - 2.72% fixed-rate notes due 2019 to 2025 (2) $ 410,073 2.00 % $ 410,102 2.00 % Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035 (3) 11,648 4.71 11,572 4.85 Subordinated debt obligations: floating-rate based on three-month LIBOR plus 3.25% due in 2032 (4) 4,348 5.84 4,328 5.65 Total long-term borrowings 426,069 2.11 426,002 2.11 Total borrowings $ 3,041,069 2.39 % $ 2,461,002 2.41 % Other short-term liabilities: Collateralized customer deposits $ 291,671 0.70 % $ 382,687 0.75 % (1) Weighted average rate presented is the contractual rate which excludes premiums and discounts related to purchase accounting. (2) The June 30, 2019 balances include advances payable of $410.0 million and purchase accounting premiums of $73 thousand . The December 31, 2018 balance includes advances payable of $410.0 million and purchase accounting premiums of $102 thousand . (3) The June 30, 2019 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.4 million . The December 31, 2018 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.4 million . (4) The June 30, 2019 balance includes advances payable of $5.0 million and purchase accounting discounts of $652 thousand . The December 31, 2018 balance includes advances payable of $5.0 million and purchase accounting discounts of $672 thousand . Chemical Bank is a member of the FHLB, which provides short- and long-term funding collateralized by mortgage related assets to its members. Each advance is payable at its maturity date, with a prepayment penalty for fixed-rate advances. The Corporation's FHLB advances, including both short-term and long-term, require monthly interest payments and are collateralized by commercial and residential mortgage loans totaling $7.70 billion as of June 30, 2019 . The Corporation's additional borrowing availability through the FHLB, subject to the FHLB's credit requirements and policies and based on the amount of FHLB stock owned by the Corporation, was $25.0 million at June 30, 2019 . Chemical Bank is additionally a member of the American Financial Exchange ("AFX"), through which it may borrow funds on an overnight or short-term basis with a group of pre-approved commercial banks.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers	Revenue from Contracts with Customers The Corporation earns a variety of revenue including interest and fees from customers as well as revenues from non-customers. Certain sources of revenue are recognized within interest income and are outside of the scope of ASC Topic 606, Revenue from Contracts with Customers ("ASC 606"). Other sources of revenue fall within the scope of ASC 606 and are mostly recognized within "Noninterest income" in the Consolidated Statements of Income. The Corporation recognizes revenue when the performance obligations related to the transfer of goods or services under the terms of a contract are satisfied. Some obligations are satisfied at a point in time while others are satisfied over a period of time. Revenue is recognized as the amount of consideration expected to be received in exchange for transferring goods or services to a customer and is segregated based on the nature of product and services offered as part of contractual arrangements. Revenue within the scope of ASC 606 are discussed below. • Service charges and fees on deposit accounts include fees and other charges the Corporation receives to provide various services, including but not limited to, maintaining an account with a customer, providing overdraft services, wire transfers, transferring funds, and accepting and executing stop-payment orders. The consideration includes both fixed (e.g., account maintenance fees) and transaction fees (i.e., wire-transfer fee). Fixed fees are recognized over the period of time the service is provided while transaction fees are recognized when a specific service is rendered to the customer. • Wealth management revenue includes fee income generated from personal and institutional customers. The Corporation also provides investment management services. Services are rendered over a period of time, over which revenue is recognized. Wealth management revenue also includes commissions that are earned for placing a brokerage transaction for execution, such as stocks or other investments. Revenue is recognized once the transaction is completed and the Corporation is entitled to receive consideration. • Other charges and fees for customer services includes service charges on deposit accounts and other fees including account analysis fees, monthly service fees, check orders, ATM fees and other service charges. The Corporation's performance obligation for account analysis fees and monthly service fees is generally satisfied, and therefore, revenue is recognized over the period in which the service is provided. Check orders and other deposit account related fees are largely transactional based, and therefore, the performance obligation is satisfied and related revenue recognized, at a point in time. • Other noninterest expense includes net gain or loss on sales of other real estate and repossessed assets. Revenue is recognized at the time the sale is complete and the Corporation is entitled to receive consideration, including sales that are seller financed as receipt of all payment is expected. The following table presents total noninterest income segregated between contracts with customers within the scope of ASC 606 and those within the scope of other GAAP Topics. The following additionally presents revenues from customers and non-customers that are included within noninterest expense. Three Months Ended Six Months Ended (Dollars in thousands) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Noninterest income Service charges and fees on deposit accounts $ 2,986 $ 4,462 $ 5,983 $ 8,925 Wealth management revenue 1,321 1,268 2,621 2,052 Other charges and fees for customer services 1,244 1,389 2,461 3,787 Noninterest income from contracts with customers within the scope of ASC 606 5,551 7,119 11,065 14,764 Noninterest income within the scope of other GAAP topics 32,613 30,899 51,956 63,808 Total noninterest income $ 38,164 $ 38,018 $ 63,021 $ 78,572 Noninterest expense Other $ (810 ) $ 38 $ (1,536 ) $ (684 ) Contract Balances A contract asset balance occurs when an entity performs a service for a customer before the customer pays consideration (resulting in a contract receivable) or before payment is due (resulting in a contract asset). A contract liability balance is an entity's obligation to transfer a service to a customer for which the entity has already received payment (or payment is due) from the customer. The Corporation's noninterest income streams are largely based on transactional activity, or standard month-end revenue accruals such as asset management fees based on month-end market values. Consideration is most often received immediately or shortly after the Corporation satisfies its performance obligation and revenue is recognized. The Corporation does not typically enter into long-term revenue contracts with customers, and therefore, does not experience significant contract balances. As of June 30, 2019 and December 31, 2018 , the Corporation did not have a material amount of contract balances.

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Compensation	Share-Based Compensation The Corporation maintains share-based compensation plans under which it periodically grants share-based awards for a fixed number of shares to certain officers of the Corporation. The fair value of share-based awards is recognized as compensation expense over the requisite service or performance period. During the three months ended June 30, 2019 and 2018 , share-based compensation expense related to share-based awards totaled $2.8 million and $2.4 million , respectively. During the six months ended June 30, 2019 and 2018 , share-based compensation expense related to share-based awards totaled $5.1 million and $4.1 million , respectively. The excess tax benefit realized from share-based compensation transactions during the three months ended June 30, 2019 and 2018 was an expense of $16 thousand and a benefit of $399 thousand , respectively, and during the six months ended June 30, 2019 and 2018 was a benefit of $306 thousand and $1.8 million , respectively. During the six months ended June 30, 2019 , the Corporation granted 379,260 restricted stock units to certain officers of the Corporation. On May 7, 2019, the shareholders of the Corporation approved the Stock Incentive Plan of 2019, which provides for 2,400,000 shares of the Corporation's common stock to be made available for future equity-based awards and canceled the amount of shares available for future grant under prior share-based compensation plans. At June 30, 2019 , there were 2,388,937 shares of common stock available for future grants under the Stock Incentive Plan of 2019. Stock Options The Corporation issues stock options to certain officers from time to time. The exercise price on stock options equals the current market price of the Corporation's common stock on the date of grant and stock options expire ten years from the date of grant. Stock options granted after 2012 vest ratably over a five -year period. Stock options granted prior to 2016 were fully vested upon the merger with Talmer. Stock options assumed by the Corporation in the merger with Talmer were fully vested prior to assumption. A summary of activity for the Corporation's stock options as of and for the six months ended June 30, 2019 is presented below: Non-Vested Stock Options Outstanding Stock Options Outstanding Number of Options Weighted- Average Exercise Price Per Share Weighted- Average Grant Date Fair Value Per Share Number of Options Weighted- Average Exercise Price Per Share Outstanding at December 31, 2018 221,658 $ 38.37 $ 7.16 777,443 $ 31.42 Exercised — — — (97,284 ) 29.69 Vested (65,104 ) 37.24 6.98 — — Forfeited/expired (28,566 ) 36.40 6.82 (31,874 ) 36.40 Outstanding at June 30, 2019 127,988 $ 39.38 $ 7.33 648,285 $ 31.43 Exercisable/vested at June 30, 2019 520,297 $ 29.48 The weighted-average remaining contractual terms were 5.2 years for all outstanding stock options and 4.8 years for exercisable stock options at June 30, 2019 . The intrinsic value of all outstanding in-the-money stock options and exercisable in-the-money stock options was $7.5 million and $6.8 million , respectively, at June 30, 2019 . The aggregate intrinsic values of outstanding and exercisable options at June 30, 2019 were calculated based on the closing market price of the Corporation’s common stock on June 30, 2019 of $41.11 per share less the exercise price. Options with intrinsic values less than zero, or "out-of-the-money" options, are not included in the aggregate intrinsic value reported. The total intrinsic value of stock options as of June 30, 2018 and December 31, 2018 was $19.8 million and $26.6 million , respectively. Total cash received from options exercises during the six months ended June 30, 2019 and 2018 was $338 thousand and $2.2 million , respectively. At June 30, 2019 , unrecognized compensation expense related to stock options totaled $901 thousand and is expected to be recognized over a remaining weighted average period of 2.1 years . Restricted Stock Units The Corporation grants Performance-Based Restricted Stock Units ("PRSUs") and Time-Based Restricted Stock Units ("TRSUs") (collectively referred to as "RSUs") to certain officers from time to time. The PRSUs vest based on the Corporation achieving certain performance target levels and the grantee completing the requisite service period. The PRSUs are eligible to vest from 0.5 x to 1.5 x the number of units originally granted depending on which, if any, of the performance target levels are met. However, if the minimum performance target levels are not achieved, no shares will become vested or be issued for that respective year's PRSUs. The TRSUs vest upon satisfaction of a service condition. Upon achievement of the performance target level and/or satisfaction of a service condition, as applicable, the RSUs are converted into shares of the Corporation's common stock on a one-to-one basis. Compensation expense related to RSUs is recognized over the expected requisite performance or service period, as applicable. A summary of the activity for RSUs as of and for the six months ended June 30, 2019 is presented below: Number of Units Weighted-average grant date fair value per unit Outstanding at December 31, 2018 576,490 $ 49.35 Granted 379,260 44.95 Converted into shares of common stock (123,686 ) 38.83 Forfeited/expired (21,406 ) 50.03 Outstanding at June 30, 2019 810,658 $ 48.88 At June 30, 2019 , unrecognized compensation expense related to RSUs totaled $27.6 million and is expected to be recognized over a remaining weighted average period of 3.5 years . Restricted Stock Awards The Corporation assumed restricted stock awards in the merger with Talmer that vested upon completion of service requirements. The fair value of these awards is equal to the market price of the Corporation's common stock at the date the awards were assumed with the portion of the fair value related to post-combination service. The Corporation recognizes stock-based compensation expense over the vesting period, using the straight-lined method, based upon the number of shares of restricted stock ultimately expected to vest. The following table provides information regarding restricted stock awards. All restricted stock awards fully vested during the six months ended June 30, 2019 . Nonvested restricted stock awards Number of Awards Weighted-average acquisition-date Nonvested at January 1, 2019 40,852 $ 46.23 Vested (40,852 ) 46.23 Nonvested at June 30, 2019 — $ —

Retirement Plans

Retirement Plans	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Retirement Plans	Retirement Plans The Corporation's retirement plans include a qualified defined benefit pension plan, a nonqualified pension plan, a nonqualified postretirement benefit plan, a 401(k) savings plan, and a multi-employer defined benefit plan. Qualified Defined Benefit Pension Plan The Chemical Financial Corporation Employees’ Pension Plan (the "Pension Plan") is a qualified defined-benefit, noncontributory pension plan, which provides for postretirement pension benefits for certain salaried employees of the Corporation and its subsidiary, Chemical Bank. Benefits under the Pension Plan were partially frozen effective June 30, 2006. Under the partial freeze of the Pension Plan, benefits for employees with less than 15 years of service or whose combined age plus years of service were less than 65 at June 30, 2006, were based on years of vested service at June 30, 2006 and generally the average of the employee's salary for the five years ended June 30, 2006. In addition, no employee hired after January 1, 2006 was eligible to participate in the Pension Plan. Effective September 30, 2017, the Pension and Compensation Committee approved an amendment to the Pension Plan to cease accruing additional benefits under the existing pension benefit formula after the effective date and all accrued benefits were frozen. Retirement benefits under the Pension Plan are based on years of vested service at September 30, 2017, up to a maximum of thirty years, and the employee's average annual pay for the five highest consecutive years during the ten years preceding September 30, 2017, except for employees whose benefits were previously frozen during 2006. On May 7, 2019, the Corporation's board of directors approved the termination of the Pension Plan as of August 31, 2019, subject to revocation if the Merger is not consummated. The fair value of Pension Plan assets exceeds the recorded liability by approximately $19.0 million at June 30, 2019 , which is considered actuarially sufficient for termination purposes. Pension Plan benefits are the present value of estimated future periodic payments that are attributable to services rendered by the employees to the valuation date. Benefits include the benefits expected to be paid to (a) retired or terminated employees or their beneficiaries and (b) present employees or their beneficiaries. A discount rate of 4.32% was utilized for the projected benefit obligation as of June 30, 2019 . The Pension Plan is fully funded as of June 30, 2019 . Nonqualified Pension Plan The Corporation has a supplemental defined benefit nonqualified pension plan, the Chemical Financial Corporation Supplemental Pension Plan ("SERP"). The Corporation established the SERP to provide payments to certain executive officers of the Corporation, as determined by the Compensation and Pension Committee. The Internal Revenue Code limits both the amount of eligible compensation for benefit calculation purposes and the amount of annual benefits that may be paid from a tax qualified retirement plan. The SERP was designed to provide benefits to executive officers of the Corporation that would have been entitled, calculated under the provisions of the Pension Plan, as if the limits imposed by the Internal Revenue Code did not apply. The SERP is an unfunded plan and, therefore, has no assets. Effective September 30, 2017, the Pension and Compensation Committee approved a curtailment to the SERP due to the retirement of the final remaining participant in the SERP. As of June 30, 2019 , a $333 thousand liability included in other liabilities was recorded in the Consolidated Statements of Financial Position related to a former participant of the SERP. As of June 30, 2019 , the SERP had no active participants. Nonqualified Postretirement Benefit Plan The Corporation has a nonqualified postretirement benefit plan ("Postretirement Plan") that provides medical and dental benefits, upon retirement, to a limited number of active and retired employees. The majority of the retirees are required to make contributions toward the cost of their benefits based on their years of credited service and age at retirement. Beginning January 1, 2012, the Corporation amended the Postretirement Plan to extend coverage to employees who were at least age 50 as of January 1, 2012. These employees must also retire at age 60 or older, have at least twenty-five years of service with the Corporation and be participating in the active employee group health insurance plan in order to be eligible to participate in the Corporations' Postretirement Plan. Eligible employees may also cover their spouse until age 65 as long as the spouse is not offered health insurance coverage through his or her employer. Employees and their spouses eligible to participate in the Postretirement Plan will be required to make contributions toward the cost of their benefits upon retirement, with the contribution levels designed to cover the projected overall cost of these benefits over the long-term. Retiree contributions are generally adjusted annually. The accounting for these postretirement benefits anticipates changes in future cost-sharing features such as retiree contributions, deductibles, copayments and coinsurance. The Corporation reserves the right to amend, modify or terminate these benefits at any time. The components of net periodic benefit cost for the Corporation’s qualified and nonqualified pension plans and nonqualified postretirement benefit plan are as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Defined Benefit Pension Plans Interest cost $ 1,172 $ 1,092 $ 2,345 $ 2,184 Expected return on plan assets (2,190 ) (2,220 ) (4,381 ) (4,439 ) Amortization of unrecognized net loss 141 178 281 355 Net periodic benefit cost (income) (1) $ (877 ) $ (950 ) $ (1,755 ) $ (1,900 ) Postretirement Benefit Plan Service cost (2) $ — $ 1 $ 1 $ 1 Interest cost 21 20 43 41 Amortization of unrecognized net gain (45 ) (36 ) (90 ) (71 ) Net periodic benefit cost (income) (1) $ (24 ) $ (15 ) $ (46 ) $ (29 ) (1) Net periodic benefit cost (income), excluding service cost is included "Other" operating expenses on the Consolidated Statements of Income. (2) Service cost is included in "Salaries, wages and employee benefits expense" on the Consolidated Statements of Income. 401(k) Savings Plan The Corporation's 401(k) Savings Plan is available to all employees and provides employees with tax deferred salary deductions and alternative investment options. Effective January 1, 2018, the Corporation provides a safe harbor matching contribution of the participants elective deferrals up to a maximum of 6.0% of eligible compensation up to the maximum amount allowed under the Internal Revenue Code. The Corporation's match under the 401(k) Savings Plan was $2.4 million and $4.8 million for the three and six months ended June 30, 2019 , respectively, compared to $2.0 million and $4.8 million for the three and six months ended June 30, 2018 , respectively. The 401(k) Savings Plan provides employees with the option to invest in the Corporation's common stock.

Regulatory Capital and Reserve

Regulatory Capital and Reserve Requirements	6 Months Ended
	Jun. 30, 2019
Banking and Thrift [Abstract]
Regulatory Capital and Reserve Requirements	Regulatory Capital and Reserve Requirements Federal and state banking regulations place certain restrictions on the transfer of assets, in the form of dividends, loans, or advances, from Chemical Bank to the Corporation. As of June 30, 2019 , substantially all of the assets of Chemical Bank were restricted from transfer to the Corporation in the form of loans or advances. Dividends from Chemical Bank are the principal source of funds for the Corporation. In addition to the statutory limits, the Corporation considers the overall financial and capital position of Chemical Bank prior to making any cash dividend decisions. The Corporation and Chemical Bank are subject to various regulatory capital requirements administered by federal banking agencies. Under these capital requirements, Chemical Bank must meet specific capital guidelines that involve quantitative measures of assets and certain off-balance sheet items as calculated under regulatory accounting practices. In addition, capital amounts and classifications are subject to qualitative judgments by regulators. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Consolidated Financial Statements. Management believes as of June 30, 2019 , the Corporation and Chemical Bank met all capital adequacy requirements to which they are subject. Quantitative measures established by regulation to ensure capital adequacy require minimum ratios of Tier 1 capital to average assets (Leverage Ratio) and Common Equity Tier 1, Tier 1 and Total capital to risk-weighted assets. These capital guidelines assign risk weights to on- and off-balance sheet items in arriving at total risk-weighted assets. Minimum capital levels are based upon the perceived risk of various asset categories and certain off-balance sheet instruments. Risk-weighted assets for the Corporation and Chemical Bank totaled $17.02 billion and $16.99 billion at June 30, 2019 , respectively, compared to $16.10 billion and $16.07 billion at December 31, 2018 , respectively. Effective January 1, 2015, the Corporation adopted the Basel III regulatory capital framework as approved by federal banking agencies, which was subject to a multi-year phase-in period. The adoption of this new framework modified the calculation of the various capital ratios, added a new ratio, common equity tier 1, and revised the adequately and well capitalized thresholds. In addition, Basel III establishes a new capital conservation buffer of 2.5% of risk-weighted assets, which was phased-in over a multi-year period beginning January 1, 2016. The capital conservation buffer for 2019 is 2.5% , which is now fully phased-in, and was 1.875% for 2018 . The Corporation has elected to opt-out of including accumulated other comprehensive income in common equity tier 1 capital. At June 30, 2019 and December 31, 2018 , Chemical Bank's capital ratios exceeded the quantitative capital ratios required for an institution to be considered "well-capitalized." Significant factors that may affect capital adequacy include, but are not limited to, a disproportionate growth in assets versus capital and a change in mix or credit quality of assets. There are no conditions or events since that notification that management believes have changed the institutions' category. The summary below compares the actual capital amounts and ratios with the quantitative measures established by regulation to ensure capital adequacy: Actual Minimum Required for Capital Adequacy Purposes Including Capital Conservation Buffer Required to be Well Capitalized Under Prompt Corrective Action Regulations (Dollars in thousands) Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio June 30, 2019 Total Capital to Risk-Weighted Assets Corporation $ 1,951,444 11.5 % $ 1,787,527 10.5 % N/A N/A Chemical Bank 1,928,735 11.3 1,784,388 10.5 $ 1,699,417 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,813,446 10.7 1,447,046 8.5 N/A N/A Chemical Bank 1,806,734 10.6 1,444,504 8.5 1,359,534 8.0 Common Equity Tier 1 Capital to Risk-Weighted Assets Corporation 1,813,446 10.7 1,191,685 7.0 N/A N/A Chemical Bank 1,806,734 10.6 1,189,592 7.0 1,104,621 6.5 Leverage Ratio Corporation 1,813,446 8.7 833,418 4.0 N/A N/A Chemical Bank 1,806,734 8.7 832,372 4.0 1,040,465 5.0 December 31, 2018 Total Capital to Risk-Weighted Assets Corporation $ 1,855,922 11.5 % $ 1,590,323 9.9 % N/A N/A Chemical Bank 1,825,742 11.4 1,586,719 9.9 $ 1,606,804 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,723,004 10.7 1,268,232 7.9 N/A N/A Chemical Bank 1,708,724 10.6 1,265,358 7.9 1,285,444 8.0 Common Equity Tier 1 Capital to Risk-Weighted Asset Corporation 1,723,004 10.7 1,026,664 6.4 N/A N/A Chemical Bank 1,708,724 10.6 1,024,338 6.4 1,044,423 6.5 Leverage Ratio Corporation 1,723,004 8.7 793,669 4.0 N/A N/A Chemical Bank 1,708,724 8.6 792,184 4.0 990,230 5.0

Earnings Per Common Share

Earnings Per Common Share	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share The two-class method is used in the calculation of basic and diluted earnings per share. Under the two-class method, earnings available to common shareholders for the period are allocated between common shareholders and participating securities according to dividends declared (or accumulated) and participating rights in undistributed earnings. Average shares of common stock for diluted net income per common share include shares to be issued upon the exercise of stock options granted under the Corporation’s share-based compensation plans, restricted stock units that may be converted to stock, restricted stock awards and stock to be issued under the deferred stock compensation plan for non-employee directors. The factors used in the earnings per share computation follow: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share data) 2019 2018 2019 2018 Net income $ 69,594 $ 68,988 $ 132,536 $ 140,584 Net income allocated to participating securities — 40 24 105 Net income allocated to common shareholders (1) $ 69,594 $ 68,948 $ 132,512 $ 140,479 Weighted average common shares - issued 71,554 71,371 71,526 71,334 Average unvested restricted share awards — (42 ) (12 ) (54 ) Weighted average common shares outstanding - basic 71,554 71,329 71,514 71,280 Effect of dilutive securities Weighted average common stock equivalents 718 697 693 686 Weighted average common shares outstanding - diluted 72,272 72,026 72,207 71,966 EPS available to common shareholders Basic earnings per common share $ 0.97 $ 0.97 $ 1.85 $ 1.97 Diluted earnings per common share $ 0.96 $ 0.96 $ 1.84 $ 1.95 (1) Net income allocated to common shareholders for basic and diluted earnings per share may differ under the two-class method as a result of adding common share equivalents for options to dilutive shares outstanding, which alters the ratio used to allocate net income to common shareholders and participating securities for the purposes of calculating diluted earnings per share. For the effect of dilutive securities, the average stock valuation is $41.46 per share and $56.46 per share for the three months ended June 30, 2019 and 2018 , respectively, and $42.33 per share and $56.35 per share for the six months ended June 30, 2019 and 2018 , respectively. The average number of exercisable employee stock option awards outstanding that were "out-of-the-money," whereby the option exercise price per share exceeded the market price per share and, therefore, were not included in the computation of diluted earnings per common share because they would have been anti-dilutive totaled 41,695 and 46,940 for the three and six months ended June 30, 2019 , respectively, and 59,303 and 65,114 for the three and six months ended June 30, 2018

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Accumulated Other Comprehensive Loss	Accumulated Other Comprehensive Loss The following table summarizes the changes within each component of accumulated other comprehensive income (loss), net of related tax benefit/expense for the three and six months ended June 30, 2019 , and 2018 : (Dollars in thousands) Unrealized gains (losses) on securities carried at fair value, net of tax Defined Benefit Pension Plan, net of tax Unrealized gains (losses) on cash flow hedges, net of tax Total For the three months ended June 30, 2019 Beginning balance at April 1, 2019 $ (8,260 ) $ (28,691 ) $ (1,556 ) $ (38,507 ) Other comprehensive income (loss) before reclassifications 29,079 — (16,771 ) 12,308 Amounts reclassified from accumulated other comprehensive income (loss) (3,286 ) 76 (992 ) (4,202 ) Net current period other comprehensive income (loss) 25,793 76 (17,763 ) 8,106 Ending balance $ 17,533 $ (28,615 ) $ (19,319 ) $ (30,401 ) For the three months ended June 30, 2018 Beginning balance at April 1, 2018 $ (32,501 ) $ (19,696 ) $ 11,143 $ (41,054 ) Other comprehensive income (loss) before reclassifications (9,182 ) — 3,240 (5,942 ) Amounts reclassified from accumulated other comprehensive income (loss) (2 ) 112 (465 ) (355 ) Net current period other comprehensive income (loss) (9,184 ) 112 2,775 (6,297 ) Ending balance $ (41,685 ) $ (19,584 ) $ 13,918 $ (47,351 ) For the six months ended June 30, 2019 Beginning balance at January 1, 2019 $ (37,772 ) $ (28,766 ) $ 5,428 $ (61,110 ) Other comprehensive income (loss) before reclassifications 58,660 — (22,737 ) 35,923 Amounts reclassified from accumulated other comprehensive income (loss) (3,355 ) 151 (2,010 ) (5,214 ) Net current period other comprehensive income (loss) 55,305 151 (24,747 ) 30,709 Ending balance $ 17,533 $ (28,615 ) $ (19,319 ) $ (30,401 ) For the six months ended June 30, 2018 Beginning balance at December 31, 2017 $ (10,348 ) $ (19,808 ) $ 4,658 $ (25,498 ) Cumulative effect adjustment of change in accounting policy, net of tax impact (1) $ (344 ) $ — $ 3 (341 ) Beginning balance at January 1, 2018 (10,692 ) (19,808 ) 4,661 (25,839 ) Other comprehensive income (loss) before reclassifications (30,991 ) — 9,531 (21,460 ) Amounts reclassified from accumulated other comprehensive income (loss) (2 ) 224 (274 ) (52 ) Net current period other comprehensive income (loss) (30,993 ) 224 9,257 (21,512 ) Ending balance $ (41,685 ) $ (19,584 ) $ 13,918 $ (47,351 ) (1) Refer to Note 1 , Basis of Presentation and Significant Accounting Policies for further details on the adoption of ASU 2016-01 and ASU 2017-12. The following table summarizes the amounts reclassified out of each component of accumulated other comprehensive income (loss) for the three and six months ended June 30, 2019 , and 2018 : (Dollars in thousands) Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) Affected Line Item in the Income Statement Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Gains and losses on investment securities carried at fair value $ 4,160 $ 3 $ 4,247 $ 3 Net gain on sale of investment securities (noninterest income) (874 ) (1 ) (892 ) (1 ) Income tax expense $ 3,286 $ 2 $ 3,355 $ 2 Net Income Amortization of defined benefit pension plan items $ 96 $ 142 $ 191 $ 284 Salaries, wages and employee benefits (operating expenses) (20 ) (30 ) (40 ) (60 ) Income tax expense $ 76 $ 112 151 $ 224 Net Loss Gains and losses on cash flow hedges $ (1,256 ) $ (589 ) $ (2,544 ) $ (347 ) Interest on short-term borrowings (interest expense) 264 124 534 73 Income tax benefit $ (992 ) $ (465 ) $ (2,010 ) $ (274 ) Net Income

Basis of Presentation and Sig_2

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2019
Accounting Policies [Abstract]
Nature of Operations	Nature of Operations Chemical Financial Corporation ("Corporation" or "Chemical") operates in a single operating segment — commercial banking. The Corporation is a financial holding company, headquartered in Detroit, Michigan, that operates through one commercial bank, Chemical Bank. Chemical Bank operates within Michigan, Ohio and Northern Indiana as a Michigan state-chartered commercial bank. Chemical Bank operates through an internal organizational structure of six regional banking units and offers a full range of traditional banking and fiduciary products and services to the residents and business customers in the Corporation's geographical market areas. The products and services offered by the regional banking units, through branch banking offices, are generally consistent throughout the Corporation, as is the pricing of those products and services. The marketing of products and services throughout the Corporation's regional banking units is generally uniform, as many of the markets served by the regional banking units overlap. The distribution of products and services is generally uniform throughout the Corporation's regional banking units and is achieved primarily through retail branch banking offices, automated teller machines and electronically accessed banking products. The Corporation's primary sources of revenue are interest from its loan products and investment securities, service charges and fees from customer deposit accounts, wealth management revenue and net gain on sale of loans and other mortgage banking revenue.
Basis of Presentation and Principles of Consolidation	Basis of Presentation and Principles of Consolidation The accompanying unaudited Consolidated Financial Statements of the Corporation and its subsidiaries have been prepared in accordance with United States ("U.S.") generally accepted accounting principles ("GAAP") for interim financial information and with instructions to Form 10-Q, Securities and Exchange Commission ("SEC") rules and interpretive releases and prevailing practices within the banking industry and Rule 10-01 of Regulation S-X. Accordingly, the interim Consolidated Financial Statements do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with the Corporation’s Consolidated Financial Statements and footnotes thereto included in the Corporation’s Annual Report on Form 10-K for the year ended December 31, 2018 . In the opinion of management, the accompanying unaudited interim Consolidated Financial Statements contain all adjustments believed necessary to present fairly the financial condition and results of operations of the Corporation for the periods presented. All significant income and expenses are recorded on the accrual basis. Intercompany accounts and transactions have been eliminated in preparing the Consolidated Financial Statements. Operating results for the six months ended June 30, 2019 are not necessarily indicative of the results that may be expected for the year ending December 31, 2019 .
Proposed Merger with TCF Financial Corporation	Pending Merger with TCF Financial Corporation Chemical and TCF Financial Corporation ("TCF") have entered into an Agreement and Plan of Merger, dated as of January 27, 2019, which we refer to as the merger agreement. Under the merger agreement, Chemical and TCF have agreed to combine their respective companies in a merger of equals, pursuant to which TCF will merge with and into Chemical, with Chemical continuing as the surviving entity, in a transaction we refer to as the merger. Immediately following the merger or at such later time as the parties may mutually agree, Chemical Bank will merge with and into TCF National Bank, with TCF National Bank as the surviving bank, in a transaction we refer to as the bank merger. The merger has received all necessary regulatory approvals in addition to approvals from the shareholders of both companies. The pending transaction is anticipated to close on August 1, 2019, subject to satisfaction of customary closing conditions. The transaction is discussed in more detail in Note 2 .
Use of Estimates	Use of Estimates Management makes estimates and assumptions that affect the amounts reported in the Consolidated Financial Statements and accompanying footnotes. Estimates that are particularly susceptible to significant change include the determination of the allowance for loan losses, expected cash flows from acquired loans, income taxes and the valuation of loan servicing rights. Actual results could differ from these estimates.
Reclassifications	Reclassifications Certain amounts appearing in the Consolidated Financial Statements and notes thereto for prior periods have been reclassified to conform to the current presentation. The reclassification had no effect on net income or shareholders’ equity as previously reported, except in case of the cumulative effect adjustment of change in accounting policy as noted.
Recently Adopted Accounting Policy and Principles	Recently Adopted Accounting Principles Standard Description Adoption Date Effect on the financial statements ASU No. 2014-09 - Revenue from Contracts with Customers (Topic 606) ASU No. 2016-08 - Principal versus Agent Considerations ASU No. 2016-10 - Identifying Performance Obligations and Licensing ASU No. 2016-12 - Narrow-scope Improvements and Practical Expedients ("Updates to Topic 606") The core principle of the Updates to 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. The standard is intended to clarify and converge the revenue recognition principles under GAAP and International Financial Reporting Standards and to streamline revenue recognition requirements in addition to expanding required revenue recognition disclosures. January 1, 2018 under the modified retrospective method A large majority of the Corporation's revenue is derived from net interest income, which is excluded from the scope of the guidance. Following detailed review of the Corporation's revenue streams not derived from net interest income on financial assets and liabilities, management identified the recognition of gains from other real estate sales financed by the Corporation to be in the scope of this amended guidance. Effective January 1, 2018, revenue for new seller financed other real estate owned sales is determined according to the Updates to Topic 606. If all qualifications are met, gains associated with the sales are recognized into income at the time of closing and therefore not deferred. The cumulative effect of the Updates to Topic 606 increased retained earnings by $1.2 million upon adoption. Additional required disclosures have been included in Note 15, Revenue from Contracts with Customers. The adoption is not expected to have a material impact on the Corporation's net income on an ongoing basis. Refer to Note 6, Other Real Estate Owned and Repossessed Assets, for further detail. ASU No. 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01") ASU 2016-01 amended current guidance by: (i) requiring equity investments with readily determinable fair values to be measured at fair value with changes in fair value recognized in net income, (ii) allowing an entity to measure equity investments that do not have readily determinable fair values at either fair value or cost minus impairment, changes in measurement is recognized in net income, (iii) simplifying impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iv) eliminating the requirement to disclose the methods and assumptions used to estimate the fair value of financial instruments measured at amortized cost; (v) requiring the use of exit price notion when measuring the fair value of financial instruments; (vi) requiring recognition of changes in the fair value related to instrument-specific credit risk in other comprehensive income if financial liabilities are measured at fair value, (vii) requiring separate presentation in financial statements by measurement category, and (viii) clarifying that an entity should evaluate the need for valuation allowance on deferred tax assets related to available-for-sale securities in combination with the entity’s other deferred tax assets. January 1, 2018 using a modified retrospective approach with the exception of disclosure requirements which are adopted on a prospective basis The Corporation identified available-for-sale investment securities qualifying as equity investments in the securities portfolio at January 1, 2018. The adoption resulted in recognizing the unrealized fair value related to the identified equity investments as a cumulative effect to retained earnings of $0.3 million. In addition, the Corporation has updated disclosures related to the fair value of financial instruments to the use of the exit price notion. Standard Description Adoption Date Effect on the financial statements ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts as Cash Payments ("ASU 2016-15") ASU 2016-15 was issued to reduce diversity in practice and prevent financial statement restatements by clarifying the presentation and classification of cash receipts and cash payments within the statement of cash flows. Cash flow issues include: debt prepayment or debt extinguishment costs, settlement of insurance claims, proceeds from the settlement of corporate-owned and bank-owned life insurance policies, distribution received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. January 1, 2018 using retrospective application The adoption did not have a material effect on the presentation of our Consolidated Statements of Cash Flows, as current policies are either already in-line with the clarifications in the updated guidance, or the related cash flows are not material. ASU No. 2017-07 - Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost ("ASU 2017-07") ASU 2017-07 improves the income statement presentation of net periodic benefit cost for an entity's pension and postretirement plans. The standard requires employers to disaggregate current service costs from other components of net benefit cost and present it with other compensation cost. Additionally net benefit cost becomes eligible for capitalization. January 1, 2018 using the retrospective transition method The adoption did not have a material effect on the Consolidated Statements of Income during the year ended December 31, 2018. ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvement to Account for Hedging Activities ("ASU 2017-12") ASU 2017-12 eliminates the separate measurement of hedge ineffectiveness as well as the benchmark interest rate concept when applying hedge risk to variable-rate instruments. It also allows a company to elect to perform subsequent effectiveness assessments qualitatively if the initial quantitative hedge effectiveness assessment is found to be highly effective. January 1, 2018 with a cumulative effect adjustment The early adoption resulted in a cumulative adjustment from opening retained earnings to accumulated other comprehensive income of $3 thousand, which represented all previously recognized hedge ineffectiveness. ASU No. 2018-15 - Intangible-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract ("ASU 2018-15") ASU 2018-15 clarifies the accounting treatment for implementation costs for hosting arrangements that are service contracts. The amendments in this update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal use software in accordance with subtopic 350-40. Under this guidance costs for implementation activities during the development stage shall be capitalized. The said capitalized-costs shall be expensed over the term of the hosting arrangement. Third quarter of 2018 applied retrospectively The early adoption in the third quarter of 2018 did not have a material effect on the Consolidated Financial Statements. Standard Description Adoption Date Effect on the financial statements ASU No. 2016-02 - Leases (Topic 842) ASU No. 2018-10 - Codification Improvements to Topic 842, Leases ASU No. 2018-11 - Leases (Topic 842): Targeted Improvements ASU No. 2018-20 - Leases (Topic 842): Narrow Scope Improvements for Lessors ASU No. 2019-01 - Leases (Topic 842): Codification Improvements In February 2016, the FASB established Topic 842, Leases, by issuing Accounting Standards Update (ASU), No. 2016-02, which requires lessees to recognize leases on-balance sheet, lessors to classify leases as sales-type, direct financing, or operating, and disclose key information about leasing arrangements. Topic 842 was subsequently amended by ASU No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842; ASU No. 2018-10, Codification Improvements to Topic 842, Leases; ASU No. 2018-11, Targeted Improvements; ASU No. 2018-20, Narrow Scope Improvements for Lessors; and ASU No. 2019-01, Leases (Topic 842): Codification Improvements. This guidance provides that lessees will be required to recognize the following for all operating leases (with the exception of short-term leases): 1) a lease liability, which is the present value of a lessee's obligation to make lease payments, and 2) a right-of-use (ROU) 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. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. Upon adoption, a modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. January 1, 2019 Upon adoption as of January 1, 2019, the Corporation elected certain practical expedients offered through the guidance, including foregoing the restatement of comparative periods, the use of hindsight, and the 'package of practical expedients' whereby it did not reassess (i) whether any expired or existing contracts contain leases, (ii) the lease classification for any expired or existing leases and (iii) initial direct costs for any existing leases. Effective during the six months ended 2019 , the Corporation also adopted the following standards, none of which had a material impact to the Corporation's financial statements or financial statement disclosures: Standard Effective Date 2017-06 Plan Accounting: Defined Benefit Pension Plans (Topic 960) January 1, 2019 2018-07 Compensation - Stock Compensation (Topic 718) January 1, 2019 2018-08 Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made January 1, 2019 2018-09 Codification Improvements January 1, 2019 2018-16 Derivatives and Hedging (Topic 815): Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes January 1, 2019

Basis of Presentation and Sig_3

Basis of Presentation and Significant Accounting Policies Basis of Presentation and Significant Accounting Policies (Tables)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Recently Adopted Accounting Principles	Standard Description Adoption Date Effect on the financial statements ASU No. 2014-09 - Revenue from Contracts with Customers (Topic 606) ASU No. 2016-08 - Principal versus Agent Considerations ASU No. 2016-10 - Identifying Performance Obligations and Licensing ASU No. 2016-12 - Narrow-scope Improvements and Practical Expedients ("Updates to Topic 606") The core principle of the Updates to 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. The standard is intended to clarify and converge the revenue recognition principles under GAAP and International Financial Reporting Standards and to streamline revenue recognition requirements in addition to expanding required revenue recognition disclosures. January 1, 2018 under the modified retrospective method A large majority of the Corporation's revenue is derived from net interest income, which is excluded from the scope of the guidance. Following detailed review of the Corporation's revenue streams not derived from net interest income on financial assets and liabilities, management identified the recognition of gains from other real estate sales financed by the Corporation to be in the scope of this amended guidance. Effective January 1, 2018, revenue for new seller financed other real estate owned sales is determined according to the Updates to Topic 606. If all qualifications are met, gains associated with the sales are recognized into income at the time of closing and therefore not deferred. The cumulative effect of the Updates to Topic 606 increased retained earnings by $1.2 million upon adoption. Additional required disclosures have been included in Note 15, Revenue from Contracts with Customers. The adoption is not expected to have a material impact on the Corporation's net income on an ongoing basis. Refer to Note 6, Other Real Estate Owned and Repossessed Assets, for further detail. ASU No. 2016-01 - Financial Instruments - Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities ("ASU 2016-01") ASU 2016-01 amended current guidance by: (i) requiring equity investments with readily determinable fair values to be measured at fair value with changes in fair value recognized in net income, (ii) allowing an entity to measure equity investments that do not have readily determinable fair values at either fair value or cost minus impairment, changes in measurement is recognized in net income, (iii) simplifying impairment assessment of equity investments without readily determinable fair values by requiring a qualitative assessment to identify impairment, (iv) eliminating the requirement to disclose the methods and assumptions used to estimate the fair value of financial instruments measured at amortized cost; (v) requiring the use of exit price notion when measuring the fair value of financial instruments; (vi) requiring recognition of changes in the fair value related to instrument-specific credit risk in other comprehensive income if financial liabilities are measured at fair value, (vii) requiring separate presentation in financial statements by measurement category, and (viii) clarifying that an entity should evaluate the need for valuation allowance on deferred tax assets related to available-for-sale securities in combination with the entity’s other deferred tax assets. January 1, 2018 using a modified retrospective approach with the exception of disclosure requirements which are adopted on a prospective basis The Corporation identified available-for-sale investment securities qualifying as equity investments in the securities portfolio at January 1, 2018. The adoption resulted in recognizing the unrealized fair value related to the identified equity investments as a cumulative effect to retained earnings of $0.3 million. In addition, the Corporation has updated disclosures related to the fair value of financial instruments to the use of the exit price notion. Standard Description Adoption Date Effect on the financial statements ASU No. 2016-15, Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts as Cash Payments ("ASU 2016-15") ASU 2016-15 was issued to reduce diversity in practice and prevent financial statement restatements by clarifying the presentation and classification of cash receipts and cash payments within the statement of cash flows. Cash flow issues include: debt prepayment or debt extinguishment costs, settlement of insurance claims, proceeds from the settlement of corporate-owned and bank-owned life insurance policies, distribution received from equity method investees, beneficial interests in securitization transactions and separately identifiable cash flows and application of the predominance principle. January 1, 2018 using retrospective application The adoption did not have a material effect on the presentation of our Consolidated Statements of Cash Flows, as current policies are either already in-line with the clarifications in the updated guidance, or the related cash flows are not material. ASU No. 2017-07 - Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost ("ASU 2017-07") ASU 2017-07 improves the income statement presentation of net periodic benefit cost for an entity's pension and postretirement plans. The standard requires employers to disaggregate current service costs from other components of net benefit cost and present it with other compensation cost. Additionally net benefit cost becomes eligible for capitalization. January 1, 2018 using the retrospective transition method The adoption did not have a material effect on the Consolidated Statements of Income during the year ended December 31, 2018. ASU No. 2017-12, Derivatives and Hedging (Topic 815): Targeted Improvement to Account for Hedging Activities ("ASU 2017-12") ASU 2017-12 eliminates the separate measurement of hedge ineffectiveness as well as the benchmark interest rate concept when applying hedge risk to variable-rate instruments. It also allows a company to elect to perform subsequent effectiveness assessments qualitatively if the initial quantitative hedge effectiveness assessment is found to be highly effective. January 1, 2018 with a cumulative effect adjustment The early adoption resulted in a cumulative adjustment from opening retained earnings to accumulated other comprehensive income of $3 thousand, which represented all previously recognized hedge ineffectiveness. ASU No. 2018-15 - Intangible-Goodwill and Other-Internal-Use Software (Subtopic 350-40): Customer's Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract ("ASU 2018-15") ASU 2018-15 clarifies the accounting treatment for implementation costs for hosting arrangements that are service contracts. The amendments in this update align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal use software in accordance with subtopic 350-40. Under this guidance costs for implementation activities during the development stage shall be capitalized. The said capitalized-costs shall be expensed over the term of the hosting arrangement. Third quarter of 2018 applied retrospectively The early adoption in the third quarter of 2018 did not have a material effect on the Consolidated Financial Statements. Standard Description Adoption Date Effect on the financial statements ASU No. 2016-02 - Leases (Topic 842) ASU No. 2018-10 - Codification Improvements to Topic 842, Leases ASU No. 2018-11 - Leases (Topic 842): Targeted Improvements ASU No. 2018-20 - Leases (Topic 842): Narrow Scope Improvements for Lessors ASU No. 2019-01 - Leases (Topic 842): Codification Improvements In February 2016, the FASB established Topic 842, Leases, by issuing Accounting Standards Update (ASU), No. 2016-02, which requires lessees to recognize leases on-balance sheet, lessors to classify leases as sales-type, direct financing, or operating, and disclose key information about leasing arrangements. Topic 842 was subsequently amended by ASU No. 2018-01, Land Easement Practical Expedient for Transition to Topic 842; ASU No. 2018-10, Codification Improvements to Topic 842, Leases; ASU No. 2018-11, Targeted Improvements; ASU No. 2018-20, Narrow Scope Improvements for Lessors; and ASU No. 2019-01, Leases (Topic 842): Codification Improvements. This guidance provides that lessees will be required to recognize the following for all operating leases (with the exception of short-term leases): 1) a lease liability, which is the present value of a lessee's obligation to make lease payments, and 2) a right-of-use (ROU) 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. Lessor accounting under the new guidance remains largely unchanged as it is substantially equivalent to existing guidance for sales-type leases, direct financing leases and operating leases. Upon adoption, a modified retrospective transition approach is required, applying the new standard to all leases existing at the date of initial application. January 1, 2019 Upon adoption as of January 1, 2019, the Corporation elected certain practical expedients offered through the guidance, including foregoing the restatement of comparative periods, the use of hindsight, and the 'package of practical expedients' whereby it did not reassess (i) whether any expired or existing contracts contain leases, (ii) the lease classification for any expired or existing leases and (iii) initial direct costs for any existing leases. Effective during the six months ended 2019 , the Corporation also adopted the following standards, none of which had a material impact to the Corporation's financial statements or financial statement disclosures: Standard Effective Date 2017-06 Plan Accounting: Defined Benefit Pension Plans (Topic 960) January 1, 2019 2018-07 Compensation - Stock Compensation (Topic 718) January 1, 2019 2018-08 Clarifying the Scope and the Accounting Guidance for Contributions Received and Contributions Made January 1, 2019 2018-09 Codification Improvements January 1, 2019 2018-16 Derivatives and Hedging (Topic 815): Inclusion of the Secured Overnight Financing Rate (SOFR) Overnight Index Swap (OIS) Rate as a Benchmark Interest Rate for Hedge Accounting Purposes January 1, 2019

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Summary of assets measured at fair value on a recurring basis	For assets and liabilities measured at fair value on a recurring basis, quantitative disclosures about the fair value measurements for each major category of assets and liabilities follow: (Dollars in thousands) Quoted Prices In Active Markets for Identical Assets Significant Other Significant Total June 30, 2019 Investment securities – carried at fair value: Government and government-sponsored enterprises $ — $ 295,726 $ — $ 295,726 State and political subdivisions — 444,085 — 444,085 Residential mortgage-backed securities — 353,622 — 353,622 Collateralized mortgage obligations — 1,939,695 — 1,939,695 Corporate bonds — 289,312 — 289,312 Trust preferred securities — 47,432 — 47,432 Total investment securities – carried at fair value — 3,369,872 — 3,369,872 Loans held-for-sale — 33,019 — 33,019 Loan servicing rights — — 60,658 60,658 Derivative assets: Customer-initiated derivatives — 69,024 — 69,024 Interest rate lock commitments — 2,687 — 2,687 Power Equity CD — 751 — 751 Risk management derivatives — 606 — 606 Total derivatives — 73,068 — 73,068 Total assets at fair value $ — $ 3,475,959 $ 60,658 $ 3,536,617 Derivative liabilities: Customer-initiated derivatives — 70,707 — 70,707 Forward contracts related to mortgage loans to be delivered for sale — 661 — 661 Power Equity CD — 751 — 751 Risk management derivatives — 25,060 — 25,060 Total derivatives — 97,179 — 97,179 Total liabilities at fair value $ — $ 97,179 $ — $ 97,179 (Dollars in thousands) Quoted Prices In Active Markets for Identical Assets Significant Other Significant Total December 31, 2018 Investment securities – carried at fair value: Government and government-sponsored enterprises $ — $ 351,700 $ — $ 351,700 State and political subdivisions — 516,286 — 516,286 Residential mortgage-backed securities — 213,428 — 213,428 Collateralized mortgage obligations — 1,601,298 — 1,601,298 Corporate bonds — 293,063 — 293,063 Trust preferred securities — 46,057 — 46,057 Total investment securities – carried at fair value — 3,021,832 — 3,021,832 Loans held-for-sale — 85,030 — 85,030 Loan servicing rights — — 71,013 71,013 Derivative assets: Customer-initiated derivatives — 26,680 — 26,680 Interest rate lock commitments — 1,049 — 1,049 Power Equity CD — 718 — 718 Risk management derivatives — 10,148 — 10,148 Total derivatives — 38,595 — 38,595 Total assets at fair value $ — $ 3,145,457 $ 71,013 $ 3,216,470 Derivative liabilities: Customer-initiated derivatives $ — $ 27,664 $ — $ 27,664 Forward contracts related to mortgage loans to be delivered for sale — 719 — 719 Power Equity CD — 718 — 718 Risk management derivatives — 3,278 — 3,278 Total derivatives — 32,379 — 32,379 Total liabilities at fair value $ — $ 32,379 $ — $ 32,379
Summary of changes in Level 3 assets measured at fair value on a recurring basis	The following table summarizes the changes in Level 3 assets measured at fair value on a recurring basis. Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 (Dollars in thousands) Loan servicing rights Balance, beginning of period $ 64,701 $ 68,837 $ 71,013 $ 63,841 Gains (losses): Recorded in earnings (realized): Recorded in "Net gain on sale of loans and other mortgage banking revenue" (6,152 ) (757 ) (14,597 ) 2,272 New originations 2,109 2,284 4,242 4,251 Balance, end of period $ 60,658 $ 70,364 $ 60,658 $ 70,364
Schedule of aggregate fair value contractual balance and gain (loss) for loans held-for-sale	The aggregate fair value, contractual balance (including accrued interest), and gain or loss for loans held-for-sale carried at fair value option was as follows: (Dollars in thousands) June 30, December 31, Aggregate fair value $ 33,019 $ 85,030 Contractual balance 31,799 82,080 Unrealized gain 1,220 2,950
Amount of gains (losses) from loans held for sale included in the Consolidated Statements of Income	The total amount of gains from loans held-for-sale included in the Consolidated Statements of Income was as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Interest income (1) $ 336 $ 445 $ 969 $ 821 Change in fair value (2) 345 484 (1,730 ) (216 ) Net gain on sales of loans (2) 5,388 4,023 11,538 5,531 Total included in earnings $ 6,069 $ 4,952 $ 10,777 $ 6,136 (1) Included in "Interest and fees on loans" in the Consolidated Statements of Income. (2)
Summary of assets measured at fair value on a nonrecurring basis	For assets measured at fair value on a nonrecurring basis, quantitative disclosures about fair value measurements for each major category of assets follow: (Dollars in thousands) Significant Unobservable Inputs (Level 3) June 30, 2019 Impaired loans $ 76,186 Other real estate and repossessed assets 3,463 Total $ 79,649 December 31, 2018 Impaired loans $ 63,247 Other real estate and repossessed assets 883 Total $ 64,130
Additional information about significant unobservable inputs used in the fair value measurement of financial assets	The following table presents additional information about the significant unobservable inputs used in the fair value measurement of financial assets measured on a nonrecurring basis that were categorized within the Level 3 of the fair value hierarchy: (Dollars in thousands) Fair Value at Valuation Technique Significant Unobservable Inputs Range Impaired loans $ 76,186 Appraisal of collateral Discount for type of collateral and age of appraisal 20%-30% Other real estate and repossessed assets 3,463 Appraisal of property Discount for type of property and age of appraisal 20%-30%
Summary of carrying amounts and estimated fair values of the financial instruments	A summary of carrying amounts and estimated fair values of the Corporation's financial instruments not recorded at fair value in their entirety on a recurring basis on the Consolidated Statements of Financial Position are disclosed in the table below. Level in Fair Value Measurement Hierarchy June 30, 2019 December 31, 2018 (Dollars in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial assets: Investment securities: Held-to-maturity Level 2 $ 565,546 $ 575,042 $ 623,599 $ 618,232 Held-to-maturity Level 3 500 460 500 440 Net loans (1) Level 3 15,745,936 15,717,256 15,159,795 14,907,789 Financial liabilities: Time deposits Level 2 $ 4,360,014 $ 4,354,554 $ 4,074,248 $ 4,041,212 Collateralized customer deposits Level 2 291,671 291,513 382,687 382,370 Short-term borrowings Level 2 2,615,000 2,614,777 2,035,000 2,034,719 Long-term borrowings Level 2 426,069 431,043 426,002 423,258 (1) Included $76.2 million and $63.2 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2019 and December 31, 2018

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2019
Investments, Debt and Equity Securities [Abstract]
Available-for-sale Securities	The following is a summary of the amortized cost and fair value of investment securities carried at fair value and investment securities held-to-maturity at June 30, 2019 and December 31, 2018 : Investment Securities Carried at Fair Value (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2019 Debt securities Government and government-sponsored enterprises $ 297,284 $ 378 $ 1,936 $ 295,726 State and political subdivisions 428,365 15,845 125 444,085 Residential mortgage-backed securities 351,790 2,807 975 353,622 Collateralized mortgage obligations 1,930,699 14,869 5,873 1,939,695 Corporate bonds 291,869 1,337 3,894 289,312 Trust preferred securities 47,672 502 742 47,432 Total $ 3,347,679 $ 35,738 $ 13,545 $ 3,369,872 December 31, 2018 Debt securities Government and government-sponsored enterprises $ 354,342 $ 713 $ 3,355 $ 351,700 State and political subdivisions 523,178 1,141 8,033 516,286 Residential mortgage-backed securities 216,990 261 3,823 213,428 Collateralized mortgage obligations 1,623,415 2,903 25,020 1,601,298 Corporate bonds 304,243 259 11,439 293,063 Trust preferred securities 47,477 324 1,744 46,057 Total $ 3,069,645 $ 5,601 $ 53,414 $ 3,021,832
Held-to-maturity Securities	Investment Securities Held-to-Maturity (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2019 State and political subdivisions $ 565,546 $ 10,576 $ 1,080 $ 575,042 Trust preferred securities 500 — 40 460 Total $ 566,046 $ 10,576 $ 1,120 $ 575,502 December 31, 2018 State and political subdivisions $ 623,599 $ 2,548 $ 7,915 $ 618,232 Trust preferred securities 500 — 60 440 Total $ 624,099 $ 2,548 $ 7,975 $ 618,672
Proceeds from sales of securities and the associated gains and losses recorded in earnings	Proceeds from sales of investment securities carried at fair value and the associated gains and losses recorded in earnings are listed below: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Proceeds $ 133,829 $ 4,215 $ 205,331 $ 4,215 Gross gains 4,180 42 4,732 42 Gross losses (20 ) (39 ) (485 ) (39 )
Amortized cost and fair value of debt securities by contractual maturity	The following is a summary of the amortized cost and fair value of investment securities at June 30, 2019 , by maturity, for both carried at fair value and held-to-maturity. The maturities of residential mortgage-backed securities and collateralized mortgage obligations are based on scheduled principal payments. The maturities of all other debt securities are based on final contractual maturity. June 30, 2019 (Dollars in thousands) Amortized Cost Fair Value Investment Securities Carried at Fair Value: Due in one year or less $ 779,977 $ 784,061 Due after one year through five years 1,292,316 1,297,464 Due after five years through ten years 812,375 809,765 Due after ten years 463,011 478,582 Total $ 3,347,679 $ 3,369,872 Investment Securities Held-to-Maturity: Due in one year or less $ 55,592 $ 55,657 Due after one year through five years 207,221 209,710 Due after five years through ten years 138,384 142,283 Due after ten years 164,849 167,852 Total $ 566,046 $ 575,502
Summary of continuous unrealized loss position of securities	The following schedule summarizes information for debt securities both carried at fair value and held-to-maturity with gross unrealized losses at June 30, 2019 and December 31, 2018 , aggregated by category and length of time that individual securities have been in a continuous unrealized loss position. As of June 30, 2019 , the Corporation's securities portfolio consisted of 1,912 securities, 512 of which were in an unrealized loss position. Less Than 12 Months 12 Months or More Total (Dollars in thousands) Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses Fair Value Gross Unrealized Losses June 30, 2019 Government and government-sponsored enterprises $ 38,077 $ 74 $ 171,701 $ 1,862 $ 209,778 $ 1,936 State and political subdivisions 10,105 15 242,873 1,190 252,978 1,205 Residential mortgage-backed securities 14,778 17 102,387 958 117,165 975 Collateralized mortgage obligations 229,853 1,684 464,641 4,189 694,494 5,873 Corporate bonds 52,131 269 113,659 3,625 165,790 3,894 Trust preferred securities 24,902 600 2,712 182 27,614 782 Total $ 369,846 $ 2,659 $ 1,097,973 $ 12,006 $ 1,467,819 $ 14,665 December 31, 2018 Government and government-sponsored enterprises $ 167,164 $ 1,672 $ 62,200 $ 1,683 $ 229,364 $ 3,355 State and political subdivisions 190,551 1,932 657,327 14,016 847,878 15,948 Residential mortgage-backed securities 20,679 85 123,757 3,738 144,436 3,823 Collateralized mortgage obligations 496,356 5,268 656,208 19,752 1,152,564 25,020 Corporate bonds 169,431 5,888 103,688 5,551 273,119 11,439 Trust preferred securities 34,623 1,640 2,725 164 37,348 1,804 Total $ 1,078,804 $ 16,485 $ 1,605,905 $ 44,904 $ 2,684,709 $ 61,389

Loans (Tables)

Loans (Tables)	6 Months Ended
	Jun. 30, 2019
Receivables [Abstract]
Summary of loans under portfolio	A summary of the Corporation's loans follows: (Dollars in thousands) Originated Acquired (1) Total Loans June 30, 2019 Commercial loan portfolio: Commercial $ 3,752,528 $ 595,357 $ 4,347,885 Commercial real estate: Owner-occupied 1,528,802 495,759 2,024,561 Non-owner occupied 2,056,531 716,146 2,772,677 Vacant land 37,155 12,807 49,962 Total commercial real estate 3,622,488 1,224,712 4,847,200 Real estate construction and land development 671,773 28,997 700,770 Subtotal 8,046,789 1,849,066 9,895,855 Consumer loan portfolio: Residential mortgage 2,722,019 944,594 3,666,613 Consumer installment 1,497,467 55,368 1,552,835 Home equity 604,835 141,765 746,600 Subtotal 4,824,321 1,141,727 5,966,048 Total loans (2) $ 12,871,110 $ 2,990,793 $ 15,861,903 December 31, 2018 Commercial loan portfolio: Commercial $ 3,287,087 $ 715,481 $ 4,002,568 Commercial real estate: Owner-occupied 1,513,532 546,025 2,059,557 Non-owner occupied 1,966,330 818,690 2,785,020 Vacant land 40,295 27,215 67,510 Total commercial real estate 3,520,157 1,391,930 4,912,087 Real estate construction and land development 566,726 30,486 597,212 Subtotal 7,373,970 2,137,897 9,511,867 Consumer loan portfolio: Residential mortgage 2,407,305 1,051,361 3,458,666 Consumer installment 1,451,352 69,722 1,521,074 Home equity 612,129 166,043 778,172 Subtotal 4,470,786 1,287,126 5,757,912 Total loans (2) $ 11,844,756 $ 3,425,023 $ 15,269,779 (1) Loans acquired in the Talmer, Lake Michigan, Monarch, Northwestern and OAK acquisitions were elected to be accounted for under ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality (ASC 310-30), by analogy. (2) Reported net of deferred costs totaling $27.2 million and $19.7 million at June 30, 2019 and December 31, 2018 , respectively.
Schedule of activity for accretable yield	Activity for the accretable yield, which includes contractually due expected cash flows for acquired loans that have been renewed or extended since the date of acquisition and continue to be accounted for in loan pools in accordance with ASC 310-30, follows: (Dollars in thousands) Talmer Lake Michigan Monarch North-western OAK Total Three Months Ended June 30, 2019 Balance at beginning of period $ 469,713 $ 68,995 $ 16,967 $ 38,644 $ 8,345 $ 602,664 Accretion recognized in interest income (36,730 ) (5,291 ) (852 ) (3,214 ) (1,334 ) (47,421 ) Net reclassification (to) from nonaccretable difference (1) 730 409 750 745 913 3,547 Balance at end of period $ 433,713 $ 64,113 $ 16,865 $ 36,175 $ 7,924 $ 558,790 Three Months Ended June 30, 2018 Balance at beginning of period $ 685,830 $ 90,156 $ 21,154 $ 55,400 $ 16,158 $ 868,698 Accretion recognized in interest income (42,136 ) (6,302 ) (962 ) (4,618 ) (2,882 ) (56,900 ) Net reclassification (to) from nonaccretable difference (1) (27,526 ) (3,412 ) (61 ) (1,051 ) 1,016 (31,034 ) Balance at end of period $ 616,168 $ 80,442 $ 20,131 $ 49,731 $ 14,292 $ 780,764 Six Months Ended June 30, 2019 Balance at beginning of period $ 505,332 $ 73,132 $ 17,832 $ 41,455 $ 9,574 $ 647,325 Accretion recognized in interest income (74,761 ) (10,842 ) (1,626 ) (6,634 ) (2,703 ) (96,566 ) Net reclassification (to) from nonaccretable difference (1) 3,142 1,823 659 1,354 1,053 8,031 Balance at end of period $ 433,713 $ 64,113 $ 16,865 $ 36,175 $ 7,924 $ 558,790 Six Months Ended June 30, 2018 Balance at beginning of period $ 731,353 $ 95,124 $ 22,496 $ 60,814 $ 17,110 $ 926,897 Accretion recognized in interest income (84,776 ) (13,060 ) (2,118 ) (9,522 ) (5,985 ) (115,461 ) Net reclassification (to) from nonaccretable difference (1) (30,409 ) (1,622 ) (247 ) (1,561 ) 3,167 (30,672 ) Balance at end of period $ 616,168 $ 80,442 $ 20,131 $ 49,731 $ 14,292 $ 780,764 (1) The net reclassification results from changes in expected cash flows of the acquired loans which may include increases in the amount of contractual principal and interest expected to be collected due to improvement in credit quality, increases in balances outstanding from advances, renewals, extensions and interest rates; as well as reductions in contractual principal and interest expected to be collected due to credit deterioration, payoffs, and decreases in interest rates.
Recorded investment of loans in the commercial loan portfolio by risk rating categories	The following schedule presents the recorded investment of loans in the commercial loan portfolio by credit risk categories at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Pass Special Mention Substandard Doubtful Total June 30, 2019 Originated Portfolio: Commercial $ 3,513,993 $ 123,194 $ 108,373 $ 6,968 $ 3,752,528 Commercial real estate: Owner-occupied 1,452,031 25,913 50,697 161 1,528,802 Non-owner occupied 2,023,577 5,516 27,433 5 2,056,531 Vacant land 35,546 96 1,513 — 37,155 Total commercial real estate 3,511,154 31,525 79,643 166 3,622,488 Real estate construction and land development 664,122 3,612 4,039 — 671,773 Subtotal 7,689,269 158,331 192,055 7,134 8,046,789 Acquired Portfolio: Commercial 505,823 62,253 25,512 1,769 595,357 Commercial real estate: Owner-occupied 462,266 18,226 14,835 432 495,759 Non-owner occupied 655,602 43,147 17,382 15 716,146 Vacant land 12,614 193 — — 12,807 Total commercial real estate 1,130,482 61,566 32,217 447 1,224,712 Real estate construction and land development 28,715 42 240 — 28,997 Subtotal 1,665,020 123,861 57,969 2,216 1,849,066 Total $ 9,354,289 $ 282,192 $ 250,024 $ 9,350 $ 9,895,855 December 31, 2018 Originated Portfolio: Commercial $ 3,118,894 $ 87,222 $ 77,036 $ 3,935 $ 3,287,087 Commercial real estate: Owner-occupied 1,430,948 32,056 50,286 242 1,513,532 Non-owner occupied 1,901,822 39,416 25,092 — 1,966,330 Vacant land 36,499 — 3,741 55 40,295 Total commercial real estate 3,369,269 71,472 79,119 297 3,520,157 Real estate construction and land development 557,040 6,108 3,578 — 566,726 Subtotal 7,045,203 164,802 159,733 4,232 7,373,970 Acquired Portfolio: Commercial 655,883 36,809 22,773 16 715,481 Commercial real estate: Owner-occupied 500,072 28,909 17,033 11 546,025 Non-owner occupied 740,900 52,546 25,244 — 818,690 Vacant land 26,978 237 — — 27,215 Total commercial real estate 1,267,950 81,692 42,277 11 1,391,930 Real estate construction and land development 29,248 97 1,141 — 30,486 Subtotal 1,953,081 118,598 66,191 27 2,137,897 Total $ 8,998,284 $ 283,400 $ 225,924 $ 4,259 $ 9,511,867
Recorded investment of loans in the consumer loan portfolio based on the credit risk profile of loans in a performing and nonperforming status	The following schedule presents the recorded investment of loans in the consumer loan portfolio based on loans in a performing status and loans in a nonperforming status at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Residential Mortgage Consumer Installment Home Equity Total Consumer June 30, 2019 Originated Loans: Performing $ 2,714,383 $ 1,496,056 $ 601,348 $ 4,811,787 Nonperforming 7,636 1,411 3,487 12,534 Subtotal 2,722,019 1,497,467 604,835 4,824,321 Acquired Loans 944,594 55,368 141,765 1,141,727 Total $ 3,666,613 $ 1,552,835 $ 746,600 $ 5,966,048 December 31, 2018 Originated Loans: Performing $ 2,399,317 $ 1,450,076 $ 608,525 $ 4,457,918 Nonperforming 7,988 1,276 3,604 12,868 Subtotal 2,407,305 1,451,352 612,129 4,470,786 Acquired Loans 1,051,361 69,722 166,043 1,287,126 Total $ 3,458,666 $ 1,521,074 $ 778,172 $ 5,757,912
Summary of nonperforming loans	A summary of nonperforming assets follows: (Dollars in thousands) June 30, December 31, Nonperforming assets Nonaccrual loans: Commercial $ 37,762 $ 30,139 Commercial real estate: Owner-occupied 20,814 16,056 Non-owner occupied 21,639 23,021 Vacant land 1,446 3,337 Total commercial real estate 43,899 42,414 Real estate construction and land development 3,501 12 Residential mortgage 7,636 7,988 Consumer installment 1,411 1,276 Home equity 3,487 3,604 Total nonaccrual loans 97,696 85,433 Other real estate owned and repossessed assets 8,267 6,256 Total nonperforming assets $ 105,963 $ 91,689
Schedule representing the aging status of the recorded investment in loans by classes	Loan delinquency, excluding acquired loans accounted for under ASC 310-30, was as follows: Loans Past Due and Still Accruing (Dollars in thousands) 30-89 days past due 90 days or more past due Total past due Nonaccrual Loans Current Total loans June 30, 2019 Originated Portfolio: Commercial $ 19,158 $ 146 $ 19,304 $ 37,762 $ 3,695,462 $ 3,752,528 Commercial real estate: Owner-occupied 3,368 — 3,368 20,814 1,504,620 1,528,802 Non-owner occupied 1,714 — 1,714 21,639 2,033,178 2,056,531 Vacant land 501 — 501 1,446 35,208 37,155 Total commercial real estate 5,583 — 5,583 43,899 3,573,006 3,622,488 Real estate construction and land development 538 — 538 3,501 667,734 671,773 Residential mortgage 6,183 — 6,183 7,636 2,708,200 2,722,019 Consumer installment 3,076 — 3,076 1,411 1,492,980 1,497,467 Home equity 2,557 — 2,557 3,487 598,791 604,835 Total $ 37,095 $ 146 $ 37,241 $ 97,696 $ 12,736,173 $ 12,871,110 December 31, 2018 Originated Portfolio: Commercial $ 16,835 $ — $ 16,835 $ 30,139 $ 3,240,113 $ 3,287,087 Commercial real estate: Owner-occupied 4,657 52 4,709 16,056 1,492,767 1,513,532 Non-owner occupied 1,793 887 2,680 23,021 1,940,629 1,966,330 Vacant land 160 — 160 3,337 36,798 40,295 Total commercial real estate 6,610 939 7,549 42,414 3,470,194 3,520,157 Real estate construction and land development 247 — 247 12 566,467 566,726 Residential mortgage 1,688 — 1,688 7,988 2,397,629 2,407,305 Consumer installment 4,731 — 4,731 1,276 1,445,345 1,451,352 Home equity 3,843 488 4,331 3,604 604,194 612,129 Total $ 33,954 $ 1,427 $ 35,381 $ 85,433 $ 11,723,942 $ 11,844,756
Schedule of Impaired loans by classes	The following schedules present impaired loans by classes of loans at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Recorded investment Unpaid principal balance Related valuation allowance June 30, 2019 Impaired loans with a valuation allowance: Commercial $ 28,732 $ 31,556 $ 5,805 Commercial real estate: Owner-occupied 20,050 22,193 2,168 Non-owner occupied 18,080 19,966 1,366 Vacant land 786 1,003 59 Total commercial real estate 38,916 43,162 3,593 Real estate construction and land development 3,612 3,612 365 Residential mortgage 10,060 10,060 790 Consumer installment 1,594 1,594 109 Home equity 4,290 4,290 356 Subtotal 87,204 94,274 11,018 Impaired loans with no related valuation allowance: Commercial 28,775 29,586 — Commercial real estate: Owner-occupied 12,057 12,895 — Non-owner occupied 7,827 8,339 — Vacant land 776 1,704 — Total commercial real estate 20,660 22,938 — Real estate construction and land development 164 164 — Residential mortgage 7,235 7,235 — Consumer installment 7 7 — Home equity 1,656 1,656 — Subtotal 58,497 61,586 — Total impaired loans: Commercial 57,507 61,142 5,805 Commercial real estate: Owner-occupied 32,107 35,088 2,168 Non-owner occupied 25,907 28,305 1,366 Vacant land 1,562 2,707 59 Total commercial real estate 59,576 66,100 3,593 Real estate construction and land development 3,776 3,776 365 Residential mortgage 17,295 17,295 790 Consumer installment 1,601 1,601 109 Home equity 5,946 5,946 356 Total $ 145,701 $ 155,860 $ 11,018 (Dollars in thousands) Recorded Unpaid Related December 31, 2018 Impaired loans with a valuation allowance: Commercial $ 20,957 $ 23,781 $ 3,546 Commercial real estate: Owner-occupied 14,702 16,519 1,359 Non-owner occupied 16,833 17,452 462 Vacant land 1,008 1,208 96 Total commercial real estate 32,543 35,179 1,917 Real estate construction and land development 126 126 11 Residential mortgage 10,867 10,867 816 Consumer installment 1,126 1,126 186 Home equity 4,432 4,432 328 Subtotal 70,051 75,511 6,804 Impaired loans with no related valuation allowance: Commercial 25,093 25,934 — Commercial real estate: Owner-occupied 10,971 11,601 — Non-owner occupied 12,412 13,411 — Vacant land 2,825 3,911 — Total commercial real estate 26,208 28,923 — Real estate construction and land development 111 111 — Residential mortgage 7,537 7,537 — Consumer installment 377 377 — Home equity 1,496 1,496 — Subtotal 60,822 64,378 — Total impaired loans: Commercial 46,050 49,715 3,546 Commercial real estate: Owner-occupied 25,673 28,120 1,359 Non-owner occupied 29,245 30,863 462 Vacant land 3,833 5,119 96 Total commercial real estate 58,751 64,102 1,917 Real estate construction and land development 237 237 11 Residential mortgage 18,404 18,404 816 Consumer installment 1,503 1,503 186 Home equity 5,928 5,928 328 Total $ 130,873 $ 139,889 $ 6,804
Schedule presents information related to impaired loans	The following schedule presents additional information regarding impaired loans by classes of loans segregated by those requiring a valuation allowance and those not requiring a valuation allowance for the three and six months ended June 30, 2019 and 2018 , and the respective interest income amounts recognized: Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (Dollars in thousands) Average recorded investment Interest income recognized while on impaired status Average recorded investment Interest income recognized while on impaired status Average Interest income Average Interest income Impaired loans with a valuation allowance: Commercial $ 26,587 $ 93 $ 18,139 $ 111 $ 24,109 $ 179 $ 19,271 $ 276 Commercial real estate: Owner-occupied 17,515 130 12,949 81 17,522 255 13,510 163 Non-owner occupied 9,050 9 2,246 10 11,055 54 3,058 21 Vacant land 788 2 1,308 17 896 10 2,502 32 Total commercial real estate 27,353 141 16,503 108 29,473 319 19,070 216 Real estate construction and land development 3,730 2 243 2 3,174 4 234 4 Residential mortgage 10,011 97 12,762 115 10,005 198 13,183 232 Consumer installment 1,250 2 1,067 2 1,213 4 986 3 Home equity 3,830 24 2,812 21 3,739 46 3,253 38 Subtotal 72,761 359 51,526 359 $ 71,713 $ 750 $ 55,997 $ 769 Impaired loans with no related valuation allowance: Commercial 27,865 201 20,078 147 $ 27,510 $ 384 $ 19,102 $ 242 Commercial real estate: Owner-occupied 14,110 73 14,565 81 12,841 126 14,967 137 Non-owner occupied 16,677 58 9,539 38 16,073 105 8,349 103 Vacant land 1,140 — 3,440 — 1,787 — 2,604 — Total commercial real estate 31,927 131 27,544 119 30,701 231 25,920 240 Real estate construction and land development 102 2 1,994 2 76 4 1,051 3 Residential mortgage 7,241 29 7,075 25 7,488 57 6,606 48 Consumer installment 36 — 41 — 226 — 91 — Home equity 1,987 5 2,487 2 2,096 12 2,266 9 Subtotal 69,158 368 59,219 295 $ 68,097 $ 688 $ 55,036 $ 542 Total impaired loans: Commercial 54,452 294 38,217 258 $ 51,619 $ 563 $ 38,373 $ 518 Commercial real estate: Owner-occupied 31,625 203 27,514 162 30,363 381 28,477 300 Non-owner occupied 25,727 67 11,785 48 27,128 159 11,407 124 Vacant land 1,928 2 4,748 17 2,683 10 5,106 32 Total commercial real estate 59,280 272 44,047 227 60,174 550 44,990 456 Real estate construction and land development 3,832 4 2,237 4 3,250 8 1,285 7 Residential mortgage 17,252 126 19,837 140 17,493 255 19,789 280 Consumer installment 1,286 2 1,108 2 1,439 4 1,077 3 Home equity 5,817 29 5,299 23 5,835 58 5,519 47 Total $ 141,919 $ 727 $ 110,745 $ 654 $ 139,810 $ 1,438 $ 111,033 $ 1,311
Schedule providing information on TDRs	The following tables present the recorded investment of loans modified into TDRs during the three and six months ended June 30, 2019 and 2018 by type of concession granted. In cases where more than one type of concession was granted, the loans were categorized based on the most significant concession. Concession type (Dollars in thousands) Principal Principal Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2019 Commercial loan portfolio: Commercial $ 14 $ 12 $ 426 $ 3,351 13 $ 3,818 $ 3,803 Commercial real estate: Owner-occupied 156 — 268 — 4 436 424 Non-owner occupied — — 140 — 1 154 140 Vacant land — — — 244 1 269 244 Total commercial real estate 156 — 408 244 6 859 808 Total commercial 170 12 834 3,595 19 4,677 4,611 Consumer loan portfolio: Residential mortgage 81 — 330 — 4 422 411 Consumer installment 15 39 13 — 6 70 67 Home equity 167 19 168 — 8 371 354 Total consumer 263 58 511 — 18 863 832 Total loans $ 433 $ 70 $ 1,345 $ 3,595 37 $ 5,540 $ 5,443 For the six months ended June 30, 2019 Commercial loan portfolio: Commercial $ 388 $ 12 $ 867 $ 6,892 24 $ 8,386 $ 8,159 Commercial real estate: Owner-occupied 2,863 103 297 1,360 9 4,649 4,623 Non-owner occupied — — 140 — 1 154 140 Vacant land 22 — — 244 2 293 266 Total commercial real estate 2,885 103 437 1,604 12 5,096 5,029 Total Commercial 3,273 115 1,304 8,496 36 13,482 13,188 Consumer loan portfolio: Residential mortgage 248 75 330 — 6 679 653 Consumer installment 61 65 13 — 17 149 139 Home equity 275 19 168 — 11 482 462 Total Consumer 584 159 511 — 34 1,310 1,254 Total loans $ 3,857 $ 274 $ 1,815 $ 8,496 70 $ 14,792 $ 14,442 Concession type (Dollars in thousands) Principal Principal Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2018 Commercial loan portfolio: Commercial $ 740 $ — $ 218 $ — 13 $ 969 $ 958 Commercial real estate: Owner-occupied 370 — 162 31 6 575 563 Total commercial real estate 370 — 162 31 6 575 563 Total commercial 1,110 — 380 31 19 1,544 1,521 Consumer loan portfolio: Residential mortgage 131 40 39 — 3 215 210 Consumer installment 15 44 10 — 9 72 69 Home equity 81 — 87 — 4 171 168 Total consumer 227 84 136 — 16 458 447 Total loans $ 1,337 $ 84 $ 516 $ 31 35 $ 2,002 $ 1,968 For the six months ended June 30, 2018 Commercial loan portfolio: Commercial $ 1,643 $ — $ 1,283 $ 261 31 $ 3,204 $ 3,187 Commercial real estate: Owner-occupied 370 — 888 513 8 1,783 1,771 Non-owner occupied 68 — — — 1 74 68 Total commercial real estate 438 — 888 513 9 1,857 1,839 Total Commercial 2,081 — 2,171 774 40 5,061 5,026 Consumer loan portfolio: Residential mortgage 269 40 39 — 7 357 348 Consumer installment 86 67 38 — 25 200 191 Home equity 266 — 115 — 9 424 381 Total Consumer 621 107 192 — 41 981 920 Total loans $ 2,702 $ 107 $ 2,363 $ 774 81 $ 6,042 $ 5,946 The following schedule presents the Corporation's TDRs at June 30, 2019 and December 31, 2018 : (Dollars in thousands) Accruing TDRs Nonaccrual TDRs Total June 30, 2019 Commercial loan portfolio $ 35,549 $ 26,526 $ 62,075 Consumer loan portfolio 12,304 3,397 15,701 Total $ 47,853 $ 29,923 $ 77,776 December 31, 2018 Commercial loan portfolio $ 32,508 $ 24,343 $ 56,851 Consumer loan portfolio 13,072 3,732 16,804 Total $ 45,580 $ 28,075 $ 73,655
Troubled debt restructurings on financing receivables with defaults payment	The following schedule includes TDRs for which there was a payment default during the three and six months ended June 30, 2019 and 2018 , whereby the borrower was past due with respect to principal and/or interest for 90 days or more, and the loan became a TDR during the twelve-month period prior to the default: For The Three Months Ended June 30, 2019 2018 (Dollars in thousands) Number of loans Principal balance Number of loans Principal balance Commercial loan portfolio — $ — 2 $ 67 Consumer loan portfolio 2 29 7 42 Total 2 $ 29 9 $ 109 For The Six Months Ended June 30, 2019 2018 (Dollars in thousands) Number of loans Principal balance Number of loans Principal balance Commercial loan portfolio — $ — 3 $ 149 Consumer loan portfolio 2 29 8 45 Total 2 $ 29 11 $ 194
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment	The following schedule presents, by loan portfolio segment, the changes in the allowance for the originated loan portfolio for the three and six months ended June 30, 2019 and 2018 . (Dollars in thousands) Commercial Loan Portfolio Consumer Loan Portfolio Total Originated Loan Portfolio Changes in allowance for loan losses for the three months ended June 30, 2019: Beginning balance $ 84,010 $ 26,274 $ 110,284 Provision for loan losses 4,848 2,654 7,502 Charge-offs (2,013 ) (1,611 ) (3,624 ) Recoveries 1,055 750 1,805 Ending balance $ 87,900 $ 28,067 $ 115,967 Changes in allowance for loan losses for the six months ended June 30, 2019: Beginning balance $ 82,759 $ 26,805 $ 109,564 Provision for loan losses 6,712 3,269 9,981 Charge-offs (3,447 ) (3,382 ) (6,829 ) Recoveries 1,876 1,375 3,251 Ending balance $ 87,900 $ 28,067 $ 115,967 Changes in allowance for loan losses for the three months ended June 30, 2018: Beginning balance $ 67,744 $ 27,018 $ 94,762 Provision for loan losses 7,923 1,649 9,572 Charge-offs (3,890 ) (1,836 ) (5,726 ) Recoveries 888 519 1,407 Ending balance $ 72,665 $ 27,350 $ 100,015 Changes in allowance for loan losses for the six months ended June 30, 2018: Beginning balance $ 66,133 $ 25,754 $ 91,887 Provision for loan losses 11,323 4,505 15,828 Charge-offs (6,484 ) (4,066 ) (10,550 ) Recoveries 1,693 1,157 2,850 Ending balance $ 72,665 $ 27,350 $ 100,015 The following schedule presents, by loan portfolio, the changes in the allowance for the acquired loan portfolio. (Dollars in thousands) Commercial Consumer Total Acquired Loan Portfolio Changes in allowance for loan losses for the three months ended June 30, 2019: Beginning balance $ — $ — $ — Provision for loan losses — — — Charge-offs — — — Recoveries — — — Ending balance $ — $ — $ — Changes in allowance for loan losses for the six months ended June 30, 2019: Beginning balance $ 420 $ — $ 420 Provision for loan losses (420 ) — (420 ) Charge-offs — — — Recoveries — — — Ending balance $ — $ — $ — The following schedule presents by loan portfolio segment, details regarding the balance in the allowance and the recorded investment in loans at June 30, 2019 and December 31, 2018 by impairment evaluation method. (Dollars in thousands) Commercial Consumer Total Allowance for loan losses balance at June 30, 2019 attributable to: Loans individually evaluated for impairment $ 9,763 $ 1,255 $ 11,018 Loans collectively evaluated for impairment 78,137 26,812 104,949 Loans accounted for under ASC 310-30 — — — Total $ 87,900 $ 28,067 $ 115,967 Recorded investment (loan balance) at June 30, 2019: Loans individually evaluated for impairment $ 120,859 $ 24,842 $ 145,701 Loans collectively evaluated for impairment 7,925,930 4,799,479 12,725,409 Loans accounted for under ASC 310-30 1,849,066 1,141,727 2,990,793 Total $ 9,895,855 $ 5,966,048 $ 15,861,903 (Dollars in thousands) Commercial Loan Portfolio Consumer Loan Portfolio Total Allowance for loan losses balance at December 31, 2018 attributable to: Loans individually evaluated for impairment $ 5,474 $ 1,330 $ 6,804 Loans collectively evaluated for impairment 77,285 25,475 102,760 Loans acquired with deteriorated credit quality 420 — 420 Total $ 83,179 $ 26,805 $ 109,984 Recorded investment (loan balance) at December 31, 2018: Loans individually evaluated for impairment $ 105,038 $ 25,835 $ 130,873 Loans collectively evaluated for impairment 7,268,932 4,444,951 11,713,883 Loans acquired with deteriorated credit quality 2,137,897 1,287,126 3,425,023 Total $ 9,511,867 $ 5,757,912 $ 15,269,779

Other Real Estate Owned and R_2

Other Real Estate Owned and Repossessed Assets (Tables)	6 Months Ended
	Jun. 30, 2019
Other Real Estate [Abstract]
Tabular disclosure of the changes in non-covered and covered other real estate on properties owned	Changes in other real estate owned and repossessed assets, included in interest receivable and other assets on the Consolidated Statements of Financial Position, were as follows: (Dollars in thousands) Other real estate Repossessed Balance at January 1, 2019 $ 5,832 $ 424 Additions (1) 5,420 1,309 Net payments received (214 ) — Disposals (2,372 ) (1,403 ) Write-downs (729 ) — Balance at June 30, 2019 $ 7,937 $ 330 Balance at January 1, 2018 $ 8,182 $ 625 Transfers based on adoption of ASU 2014-09 (2) (189 ) — Additions (1) 2,448 2,645 Net payments received (139 ) — Disposals (4,642 ) (2,319 ) Write-downs (783 ) — Balance at June 30, 2018 $ 4,877 $ 951 (1) Includes loans transferred to other real estate owned and other repossessed assets. (2) In accordance with the updates to Topic 606 adopted by the Corporation effective January 1, 2018, $1.1 million of other real estate owned sold with seller financing were reclassified on the Consolidated Statements of Financial Position to loans and the related $0.9 million of deferred gains were recognized in income as an adjustment to opening retained earnings. Refer to Note 1, Basis of Presentation and Significant Accounting Policies, for further information.
Schedule of income and expenses related to other real estate owned	Income and expenses related to other real estate owned and repossessed assets, recorded as a component of "Other" operating expenses in the Consolidated Statements of Income, were as follows: (Dollars in thousands) Other real estate owned Repossessed assets For the three months ended June 30, 2019 Net gain (loss) on sale $ 824 $ (14 ) Write-downs (435 ) — Net operating expenses (248 ) (2 ) Total $ 141 $ (16 ) For the six months ended June 30, 2019 Net gain (loss) on sale $ 1,568 $ (32 ) Write-downs (729 ) — Net operating expenses (555 ) (5 ) Total $ 284 $ (37 ) For the three months ended June 30, 2018 Net gain (loss) on sale $ 23 $ (60 ) Write-downs (132 ) — Net operating expenses (318 ) (2 ) Total $ (427 ) $ (62 ) For the six months ended June 30, 2018 Net gain (loss) on sale $ 779 $ (94 ) Write-downs (783 ) — Net operating expenses (715 ) (3 ) Total $ (719 ) $ (97 )

Loan Servicing Rights (Tables)

Loan Servicing Rights (Tables)	6 Months Ended
	Jun. 30, 2019
Transfers and Servicing [Abstract]
Schedule of activity for loan servicing rights and the related fair value changes	The following table represents the activity for LSRs and the related fair value changes: (Dollars in thousands) Commercial Real Estate Mortgage Total For the three months ended June 30, 2019 Fair value, beginning of period $ 559 $ 64,142 $ 64,701 Additions from loans sold with servicing retained — 2,109 2,109 Changes in fair value due to: Reductions from pay-offs, pay downs and run-off (34 ) (661 ) (695 ) Changes in estimates of fair value (1) — (5,457 ) (5,457 ) Fair value, end of period $ 525 $ 60,133 $ 60,658 For the six months ended June 30, 2019 Fair value, beginning of period $ 451 $ 70,562 $ 71,013 Additions from loans sold with servicing retained 138 4,104 4,242 Changes in fair value due to: 0 0 Reductions from pay-offs, pay downs and run-off (64 ) (1,430 ) (1,494 ) Changes in estimates of fair value (1) — (13,103 ) (13,103 ) Fair value, end of period $ 525 $ 60,133 $ 60,658 Principal balance of loans serviced $ 43,657 $ 6,731,556 $ 6,775,213 For the three months ended June 30, 2018 Fair value, beginning of period $ 441 $ 68,396 $ 68,837 Additions from loans sold with servicing retained 45 2,239 2,284 Changes in fair value due to: 0 Reductions from pay-offs, pay downs and run-off (29 ) (698 ) (727 ) Changes in estimates of fair value (1) — (30 ) (30 ) Fair value, end of period $ 457 $ 69,907 $ 70,364 For the six months ended June 30, 2018 Fair value, beginning of period $ 427 $ 63,414 $ 63,841 Additions from loans sold with servicing retained 88 4,163 4,251 Changes in fair value due to: Reductions from pay-offs, pay downs and run-off (58 ) (1,392 ) (1,450 ) Change in estimates of fair value (1) — 3,722 3,722 Fair value, end of period $ 457 $ 69,907 $ 70,364 Principal balance of loans serviced $ 42,490 $ 6,946,356 $ 6,988,846 (1) Represents estimated LSR value change resulting primarily from market-driven changes in interest rates and prepayments. Included in "Net gain on sale of loans and other mortgage banking revenue" in the Consolidated Statements of Income.
Schedule of assumptions included in loan servicing rights	The following table presents assumptions utilized in determining the fair value of loan servicing rights as of June 30, 2019 and December 31, 2018 . Mortgage As of June 30, 2019 Prepayment speed 6.0 - 29.72 Weighted average ("WA") discount rate 10.1 % WA cost to service/per year $ 66 WA ancillary income/per year $ 31 WA float range 2.4 % As of December 31, 2018 Prepayment speed 0.0 - 26.4% WA discount rate 10.1 % WA cost to service/per year $ 66 WA ancillary income/per year $ 31 WA float range 2.5 %

Core Deposit Intangibles (Table

Core Deposit Intangibles (Tables)	6 Months Ended
	Jun. 30, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets	The following table sets forth the carrying amount and accumulated amortization of core deposit intangible assets that are amortizable and arose from business combinations or other acquisitions: (Dollars in thousands) June 30, December 31, Gross original amount $ 56,456 $ 56,456 Accumulated amortization 30,621 27,900 Net carrying amount $ 25,835 $ 28,556
Schedule of Finite-Lived Intangible Assets, Future Amortization Expense	The estimated future amortization expense on core deposit intangible assets for periods ending after June 30, 2019 is as follows: (Dollars in thousands) Estimated amortization expense 2019 2,722 2020 4,851 2021 4,471 2022 4,218 2023 3,591 2024 and thereafter 5,982

Derivative Instruments and Ba_2

Derivative Instruments and Balance Sheet Offsetting (Tables)	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule reflecting the amount and fair value of risk management derivatives and mortgage banking and customer initiated derivatives	The following table presents the notional amount and fair value of the Corporation’s derivative instruments held or issued in connection with customer-initiated and mortgage banking activities. June 30, 2019 December 31, 2018 Fair Value Fair Value (Dollars in thousands) Notional Amount (1) Gross Derivative Assets (2) Gross Derivative Liabilities (2) Notional Amount (1) Gross Derivative Assets (2) Gross Derivative Liabilities (2) Risk management purposes: Derivatives designated as hedging instruments: Interest rate swaps $ 1,145,000 $ 606 $ 25,060 $ 820,000 $ 10,148 $ 3,278 Total risk management purposes 1,145,000 606 25,060 820,000 10,148 3,278 Customer-initiated and mortgage banking derivatives: Customer-initiated derivatives 2,908,127 69,024 70,707 2,477,640 26,680 27,664 Forward contracts related to mortgage loans to be delivered for sale 165,772 — 661 127,159 — 719 Interest rate lock commitments 149,084 2,687 — 54,848 1,049 — Power Equity CD 35,295 751 751 36,771 718 718 Total customer-initiated and mortgage banking derivatives 3,258,278 72,462 72,119 2,696,418 28,447 29,101 Total gross derivatives $ 4,403,278 $ 73,068 $ 97,179 $ 3,516,418 $ 38,595 $ 32,379 (1) Notional or contract amounts, which represent the extent of involvement in the derivatives market, are used to determine the contractual cash flows required in accordance with the terms of the agreement. These amounts are typically not exchanged, significantly exceed amounts subject to credit or market risk and are not reflected in the Consolidated Statements of Financial Position. (2) Derivative assets are included within "Interest receivable and other assets" and derivative liabilities are included within "Interest payable and other liabilities" on the Consolidated Statements of Financial Position. Included in the fair value of the derivative assets are credit valuation adjustments for counterparty credit risk totaling $1.5 million at June 30, 2019 and $901 thousand at December 31, 2018 .
Schedule reflecting the net gains (losses) relating to derivative instruments related to the changes in fair value	The following table presents the net gains (losses) related to derivative instruments reflecting the changes in fair value. Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) Location of Gain (Loss) 2019 2018 2019 2018 Forward contracts related to mortgage loans to be delivered for sale Net gain on sale of loans and other mortgage banking revenue $ (8 ) $ (21 ) $ 58 $ (391 ) Interest rate lock commitments Net gain on sale of loans and other mortgage banking revenue 929 211 1,638 763 Power Equity CD Other noninterest income — — — — Customer-initiated derivatives Other noninterest income (409 ) 39 (699 ) 366 Total gain (loss) recognized in income $ 512 $ 229 $ 997 $ 738 The following table presents the net gains (losses) recorded in accumulated other comprehensive income and the Consolidated Statements of Income relating to interest rate swaps designated as cash flow hedges for the three and six months ended June 30, 2019 and 2018 . (Dollars in thousands) Amount of gain (loss) recognized in other comprehensive income Amount of gain (loss) reclassified from other comprehensive income to interest income or expense Three Months Ended June 30, 2019 Interest rate swaps designated as cash flow hedges $ (21,229 ) $ 1,256 Three Months Ended June 30, 2018 Interest rate swaps designated as cash flow hedges 4,102 589 Six Months Ended June 30, 2019 Interest rate swaps designated as cash flow hedges $ (28,781 ) $ 2,544 Six Months Ended June 30, 2018 Interest rate swaps designated as cash flow hedges 12,065 347
Schedule of the Company's financial instruments eligible for offset, offsetting assets	The tables below present information about the Corporation’s financial instruments that are eligible for offset. Gross amounts not offset in the statements of financial position (Dollars in thousands) Gross Gross amounts offset in the statements of financial condition Net amounts presented in the statements of financial position Financial Collateral Net June 30, 2019 Offsetting derivative assets Derivative assets (1) $ 69,553 $ — $ 69,553 $ — $ — $ 69,553 Offsetting derivative liabilities Derivative liabilities (1) 95,492 — 95,492 — 37,291 58,201 December 31, 2018 Offsetting derivative assets Derivative assets (1) $ 36,791 $ — $ 36,791 $ — $ (16,120 ) $ 20,671 Offsetting derivative liabilities Derivative liabilities 30,822 — 30,822 — 430 30,392 (1) Amount does not include participated interest rate swaps, forward contracts, interest rate lock commitments and power equity CDs as these instruments are not subject to master netting or similar arrangements.
Schedule of the Company's financial instruments eligible for offset, offsetting liabilities	The tables below present information about the Corporation’s financial instruments that are eligible for offset. Gross amounts not offset in the statements of financial position (Dollars in thousands) Gross Gross amounts offset in the statements of financial condition Net amounts presented in the statements of financial position Financial Collateral Net June 30, 2019 Offsetting derivative assets Derivative assets (1) $ 69,553 $ — $ 69,553 $ — $ — $ 69,553 Offsetting derivative liabilities Derivative liabilities (1) 95,492 — 95,492 — 37,291 58,201 December 31, 2018 Offsetting derivative assets Derivative assets (1) $ 36,791 $ — $ 36,791 $ — $ (16,120 ) $ 20,671 Offsetting derivative liabilities Derivative liabilities 30,822 — 30,822 — 430 30,392 (1) Amount does not include participated interest rate swaps, forward contracts, interest rate lock commitments and power equity CDs as these instruments are not subject to master netting or similar arrangements.

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Lessee, Operating Lease, Disclosure	The following table presents balances and assumptions utilized in determining the right to use asset and lease liability for operating leases as of June 30, 2019 : June 30, 2019 Weighted-average remaining lease terms (in years) 7.85 Weighted-average discount rate 3.1 %
Lease, Cost	The components of net operating lease cost were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2019 Operating lease cost $ 2,050 3,964 Variable lease cost (1) 247 454 Sublease income (56 ) (111 ) Total lease cost (2) $ 2,241 $ 4,307 (1) Represents non-lease components such as common area maintenance, taxes, insurance and utilities. (2) Included within "Occupancy" expense in the Consolidated Statements of Income.
Lessee, Operating Lease, Liability, Maturity	Maturities of operating lease liability due under these lease arrangements as of June 30, 2019 are as follows: (Dollars in thousands) Operating Leases Remainder of 2019 $ 4,081 2020 7,490 2021 7,083 2022 6,149 2023 5,017 Thereafter 17,041 Total $ 46,861 Less: Present value discount 5,458 Lease liability $ 41,403
Operating Lease, Lease Income	The components of operating lease income were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2019 Lease income - operating leases $ 169 363 Total lease income (1) $ 169 $ 363 (1) Included within "Other" noninterest income in the Consolidated Statements of Income.

Commitments, Contingencies an_2

Commitments, Contingencies and Guarantees (Tables)	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
Summary of the reserve for unfunded commitments	A summary of the reserve for representations and warranties of the Corporation is as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Reserve balance at beginning of period $ 3,983 $ 5,105 $ 4,084 $ 5,349 Reserve reduction (807 ) (243 ) (908 ) (487 ) Charge-offs — (2 ) — (2 ) Ending reserve balance $ 3,176 $ 4,860 $ 3,176 $ 4,860 (Dollars in thousands) June 30, 2019 December 31, 2018 Reserve balance Liability for specific claims $ 454 $ 398 General allowance 2,722 3,686 Total reserve balance $ 3,176 $ 4,084

Borrowings and Other Short-Te_2

Borrowings and Other Short-Term Liabilities (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Schedule of Other Borrowings	A summary of the Corporation's short- and long-term borrowings, and other short-term liabilities follows: June 30, 2019 December 31, 2018 (Dollars in thousands) Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Short-term borrowings: FHLB advances: 2.29% - 2.60% fixed-rate notes $ 2,580,000 2.44 % $ 2,035,000 2.47 % AFX short-term borrowings 35,000 2.41 — — Total short-term borrowings $ 2,615,000 2.44 % $ 2,035,000 2.47 % Long-term borrowings: FHLB advances: 1.00% - 2.72% fixed-rate notes due 2019 to 2025 (2) $ 410,073 2.00 % $ 410,102 2.00 % Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035 (3) 11,648 4.71 11,572 4.85 Subordinated debt obligations: floating-rate based on three-month LIBOR plus 3.25% due in 2032 (4) 4,348 5.84 4,328 5.65 Total long-term borrowings 426,069 2.11 426,002 2.11 Total borrowings $ 3,041,069 2.39 % $ 2,461,002 2.41 % Other short-term liabilities: Collateralized customer deposits $ 291,671 0.70 % $ 382,687 0.75 % (1) Weighted average rate presented is the contractual rate which excludes premiums and discounts related to purchase accounting. (2) The June 30, 2019 balances include advances payable of $410.0 million and purchase accounting premiums of $73 thousand . The December 31, 2018 balance includes advances payable of $410.0 million and purchase accounting premiums of $102 thousand . (3) The June 30, 2019 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.4 million . The December 31, 2018 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.4 million . (4) The June 30, 2019 balance includes advances payable of $5.0 million and purchase accounting discounts of $652 thousand . The December 31, 2018 balance includes advances payable of $5.0 million and purchase accounting discounts of $672 thousand .

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Segregation of Noninterest Income	The following table presents total noninterest income segregated between contracts with customers within the scope of ASC 606 and those within the scope of other GAAP Topics. The following additionally presents revenues from customers and non-customers that are included within noninterest expense. Three Months Ended Six Months Ended (Dollars in thousands) June 30, 2019 June 30, 2018 June 30, 2019 June 30, 2018 Noninterest income Service charges and fees on deposit accounts $ 2,986 $ 4,462 $ 5,983 $ 8,925 Wealth management revenue 1,321 1,268 2,621 2,052 Other charges and fees for customer services 1,244 1,389 2,461 3,787 Noninterest income from contracts with customers within the scope of ASC 606 5,551 7,119 11,065 14,764 Noninterest income within the scope of other GAAP topics 32,613 30,899 51,956 63,808 Total noninterest income $ 38,164 $ 38,018 $ 63,021 $ 78,572 Noninterest expense Other $ (810 ) $ 38 $ (1,536 ) $ (684 )

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2019
Share-based Payment Arrangement [Abstract]
Summary of activity for Corporation's stock options	A summary of activity for the Corporation's stock options as of and for the six months ended June 30, 2019 is presented below: Non-Vested Stock Options Outstanding Stock Options Outstanding Number of Options Weighted- Average Exercise Price Per Share Weighted- Average Grant Date Fair Value Per Share Number of Options Weighted- Average Exercise Price Per Share Outstanding at December 31, 2018 221,658 $ 38.37 $ 7.16 777,443 $ 31.42 Exercised — — — (97,284 ) 29.69 Vested (65,104 ) 37.24 6.98 — — Forfeited/expired (28,566 ) 36.40 6.82 (31,874 ) 36.40 Outstanding at June 30, 2019 127,988 $ 39.38 $ 7.33 648,285 $ 31.43 Exercisable/vested at June 30, 2019 520,297 $ 29.48
Summary of activity for restricted stock units and awards	A summary of the activity for RSUs as of and for the six months ended June 30, 2019 is presented below: Number of Units Weighted-average grant date fair value per unit Outstanding at December 31, 2018 576,490 $ 49.35 Granted 379,260 44.95 Converted into shares of common stock (123,686 ) 38.83 Forfeited/expired (21,406 ) 50.03 Outstanding at June 30, 2019 810,658 $ 48.88 The following table provides information regarding restricted stock awards. All restricted stock awards fully vested during the six months ended June 30, 2019 . Nonvested restricted stock awards Number of Awards Weighted-average acquisition-date Nonvested at January 1, 2019 40,852 $ 46.23 Vested (40,852 ) 46.23 Nonvested at June 30, 2019 — $ —

Retirement Plans (Tables)

Retirement Plans (Tables)	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Components of net periodic benefit cost (income) for the Corporation's qualified and nonqualified pension plans and nonqualified postretirement benefits plan	The components of net periodic benefit cost for the Corporation’s qualified and nonqualified pension plans and nonqualified postretirement benefit plan are as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2019 2018 2019 2018 Defined Benefit Pension Plans Interest cost $ 1,172 $ 1,092 $ 2,345 $ 2,184 Expected return on plan assets (2,190 ) (2,220 ) (4,381 ) (4,439 ) Amortization of unrecognized net loss 141 178 281 355 Net periodic benefit cost (income) (1) $ (877 ) $ (950 ) $ (1,755 ) $ (1,900 ) Postretirement Benefit Plan Service cost (2) $ — $ 1 $ 1 $ 1 Interest cost 21 20 43 41 Amortization of unrecognized net gain (45 ) (36 ) (90 ) (71 ) Net periodic benefit cost (income) (1) $ (24 ) $ (15 ) $ (46 ) $ (29 ) (1) Net periodic benefit cost (income), excluding service cost is included "Other" operating expenses on the Consolidated Statements of Income. (2) Service cost is included in "Salaries, wages and employee benefits expense" on the Consolidated Statements of Income.

Regulatory Capital and Reserv_2

Regulatory Capital and Reserve Requirements (Tables)	6 Months Ended
	Jun. 30, 2019
Banking and Thrift [Abstract]
Corporation's and Chemical Bank's actual capital amounts and ratios with the quantitative measures established by regulation to ensure capital adequacy	The summary below compares the actual capital amounts and ratios with the quantitative measures established by regulation to ensure capital adequacy: Actual Minimum Required for Capital Adequacy Purposes Including Capital Conservation Buffer Required to be Well Capitalized Under Prompt Corrective Action Regulations (Dollars in thousands) Capital Amount Ratio Capital Amount Ratio Capital Amount Ratio June 30, 2019 Total Capital to Risk-Weighted Assets Corporation $ 1,951,444 11.5 % $ 1,787,527 10.5 % N/A N/A Chemical Bank 1,928,735 11.3 1,784,388 10.5 $ 1,699,417 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,813,446 10.7 1,447,046 8.5 N/A N/A Chemical Bank 1,806,734 10.6 1,444,504 8.5 1,359,534 8.0 Common Equity Tier 1 Capital to Risk-Weighted Assets Corporation 1,813,446 10.7 1,191,685 7.0 N/A N/A Chemical Bank 1,806,734 10.6 1,189,592 7.0 1,104,621 6.5 Leverage Ratio Corporation 1,813,446 8.7 833,418 4.0 N/A N/A Chemical Bank 1,806,734 8.7 832,372 4.0 1,040,465 5.0 December 31, 2018 Total Capital to Risk-Weighted Assets Corporation $ 1,855,922 11.5 % $ 1,590,323 9.9 % N/A N/A Chemical Bank 1,825,742 11.4 1,586,719 9.9 $ 1,606,804 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,723,004 10.7 1,268,232 7.9 N/A N/A Chemical Bank 1,708,724 10.6 1,265,358 7.9 1,285,444 8.0 Common Equity Tier 1 Capital to Risk-Weighted Asset Corporation 1,723,004 10.7 1,026,664 6.4 N/A N/A Chemical Bank 1,708,724 10.6 1,024,338 6.4 1,044,423 6.5 Leverage Ratio Corporation 1,723,004 8.7 793,669 4.0 N/A N/A Chemical Bank 1,708,724 8.6 792,184 4.0 990,230 5.0

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2019
Earnings Per Share [Abstract]
Numerator and denominator of the basic and diluted earnings per common share computations	The factors used in the earnings per share computation follow: Three Months Ended June 30, Six Months Ended June 30, (In thousands, except per share data) 2019 2018 2019 2018 Net income $ 69,594 $ 68,988 $ 132,536 $ 140,584 Net income allocated to participating securities — 40 24 105 Net income allocated to common shareholders (1) $ 69,594 $ 68,948 $ 132,512 $ 140,479 Weighted average common shares - issued 71,554 71,371 71,526 71,334 Average unvested restricted share awards — (42 ) (12 ) (54 ) Weighted average common shares outstanding - basic 71,554 71,329 71,514 71,280 Effect of dilutive securities Weighted average common stock equivalents 718 697 693 686 Weighted average common shares outstanding - diluted 72,272 72,026 72,207 71,966 EPS available to common shareholders Basic earnings per common share $ 0.97 $ 0.97 $ 1.85 $ 1.97 Diluted earnings per common share $ 0.96 $ 0.96 $ 1.84 $ 1.95 (1) Net income allocated to common shareholders for basic and diluted earnings per share may differ under the two-class method as a result of adding common share equivalents for options to dilutive shares outstanding, which alters the ratio used to allocate net income to common shareholders and participating securities for the purposes of calculating diluted earnings per share.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2019
Equity [Abstract]
Components of accumulated other comprehensive loss, net of related tax benefit/expense	The following table summarizes the changes within each component of accumulated other comprehensive income (loss), net of related tax benefit/expense for the three and six months ended June 30, 2019 , and 2018 : (Dollars in thousands) Unrealized gains (losses) on securities carried at fair value, net of tax Defined Benefit Pension Plan, net of tax Unrealized gains (losses) on cash flow hedges, net of tax Total For the three months ended June 30, 2019 Beginning balance at April 1, 2019 $ (8,260 ) $ (28,691 ) $ (1,556 ) $ (38,507 ) Other comprehensive income (loss) before reclassifications 29,079 — (16,771 ) 12,308 Amounts reclassified from accumulated other comprehensive income (loss) (3,286 ) 76 (992 ) (4,202 ) Net current period other comprehensive income (loss) 25,793 76 (17,763 ) 8,106 Ending balance $ 17,533 $ (28,615 ) $ (19,319 ) $ (30,401 ) For the three months ended June 30, 2018 Beginning balance at April 1, 2018 $ (32,501 ) $ (19,696 ) $ 11,143 $ (41,054 ) Other comprehensive income (loss) before reclassifications (9,182 ) — 3,240 (5,942 ) Amounts reclassified from accumulated other comprehensive income (loss) (2 ) 112 (465 ) (355 ) Net current period other comprehensive income (loss) (9,184 ) 112 2,775 (6,297 ) Ending balance $ (41,685 ) $ (19,584 ) $ 13,918 $ (47,351 ) For the six months ended June 30, 2019 Beginning balance at January 1, 2019 $ (37,772 ) $ (28,766 ) $ 5,428 $ (61,110 ) Other comprehensive income (loss) before reclassifications 58,660 — (22,737 ) 35,923 Amounts reclassified from accumulated other comprehensive income (loss) (3,355 ) 151 (2,010 ) (5,214 ) Net current period other comprehensive income (loss) 55,305 151 (24,747 ) 30,709 Ending balance $ 17,533 $ (28,615 ) $ (19,319 ) $ (30,401 ) For the six months ended June 30, 2018 Beginning balance at December 31, 2017 $ (10,348 ) $ (19,808 ) $ 4,658 $ (25,498 ) Cumulative effect adjustment of change in accounting policy, net of tax impact (1) $ (344 ) $ — $ 3 (341 ) Beginning balance at January 1, 2018 (10,692 ) (19,808 ) 4,661 (25,839 ) Other comprehensive income (loss) before reclassifications (30,991 ) — 9,531 (21,460 ) Amounts reclassified from accumulated other comprehensive income (loss) (2 ) 224 (274 ) (52 ) Net current period other comprehensive income (loss) (30,993 ) 224 9,257 (21,512 ) Ending balance $ (41,685 ) $ (19,584 ) $ 13,918 $ (47,351 ) (1) Refer to Note 1 , Basis of Presentation and Significant Accounting Policies for further details on the adoption of ASU 2016-01 and ASU 2017-12.
Summary of amounts reclassified out of accumulated other comprehensive income (loss)	The following table summarizes the amounts reclassified out of each component of accumulated other comprehensive income (loss) for the three and six months ended June 30, 2019 , and 2018 : (Dollars in thousands) Amounts Reclassified from Accumulated Other Comprehensive Income (Loss) Affected Line Item in the Income Statement Three Months Ended June 30, Six Months Ended June 30, 2019 2018 2019 2018 Gains and losses on investment securities carried at fair value $ 4,160 $ 3 $ 4,247 $ 3 Net gain on sale of investment securities (noninterest income) (874 ) (1 ) (892 ) (1 ) Income tax expense $ 3,286 $ 2 $ 3,355 $ 2 Net Income Amortization of defined benefit pension plan items $ 96 $ 142 $ 191 $ 284 Salaries, wages and employee benefits (operating expenses) (20 ) (30 ) (40 ) (60 ) Income tax expense $ 76 $ 112 151 $ 224 Net Loss Gains and losses on cash flow hedges $ (1,256 ) $ (589 ) $ (2,544 ) $ (347 ) Interest on short-term borrowings (interest expense) 264 124 534 73 Income tax benefit $ (992 ) $ (465 ) $ (2,010 ) $ (274 ) Net Income

Basis of Presentation and Sig_4

Basis of Presentation and Significant Accounting Policies (Details) $ in Thousands		6 Months Ended
		Jun. 30, 2019Bank	Dec. 31, 2017USD ($)
Accounting Policies [Abstract]
Number of banks through which company operates (in bank) | Bank		1
Number of regional banking units Chemical Bank operates through (in bank) | Bank		6
Business Acquisition
Cumulative effect adjustment of change in accounting policy, net of tax impact | $	[1]		$ 1,339
Retained earnings
Business Acquisition
Cumulative effect adjustment of change in accounting policy, net of tax impact | $	[1]		$ 1,680
[1]	Refer to Note 1 , Basis of Presentation and Significant Accounting Policies, Note 6 , Other Real Estate Owned and Repossessed Assets and Note 20 , Accumulated Other Comprehensive Loss for further details on the changes in accounting policy.

Basis of Presentation and Sig_5

Basis of Presentation and Significant Accounting Policies - ASU Adoptions (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustments to retained earnings	$ 699,712		$ 616,149
Right of use assets	40,500
Lease liability	$ 41,403
ASU 2014-09
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustments to retained earnings				$ 1,200
ASU 2016-01
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustments to retained earnings				300
ASU 2017-12
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Adjustments to retained earnings				$ 3
ASU 2016-02
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Right of use assets		$ 37,200
Lease liability		$ 38,200

Mergers and Acquisitions - Text

Mergers and Acquisitions - Textual (Details) $ / shares in Units, $ in Thousands	Jan. 27, 2019$ / shares	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)
Business Acquisition
Assets		$ 22,491,765	$ 21,498,341
Share price (in usd per share) | $ / shares	$ 21.58
TCF
Business Acquisition
Assets			$ 24,400,000
Preferred stock, dividend rate	5.70%
TCF
Business Acquisition
Conversion ration	0.005081

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities on a Recurring Basis (Details) - USD ($)	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017
Summary of assets measured at fair value on a recurring basis
Carried at fair value	$ 3,369,872,000		$ 3,021,832,000
Loan servicing rights	60,658,000	$ 64,701,000	71,013,000	$ 70,364,000	$ 68,837,000	$ 63,841,000
Transfers between levels	0
Measured on a Recurring Basis
Summary of assets measured at fair value on a recurring basis
Carried at fair value	3,369,872,000		3,021,832,000
Loans held-for-sale	33,019,000		85,030,000
Loan servicing rights	60,658,000		71,013,000
Total derivatives	73,068,000		38,595,000
Total assets measured at fair value on a recurring basis	3,536,617,000		3,216,470,000
Total derivatives	97,179,000		32,379,000
Total liabilities at fair value	97,179,000		32,379,000
Measured on a Recurring Basis | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Loans held-for-sale	0		0
Loan servicing rights	0		0
Total derivatives	0		0
Total assets measured at fair value on a recurring basis	0		0
Total derivatives	0		0
Total liabilities at fair value	0		0
Measured on a Recurring Basis | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	3,369,872,000		3,021,832,000
Loans held-for-sale	33,019,000		85,030,000
Loan servicing rights	0		0
Total derivatives	73,068,000		38,595,000
Total assets measured at fair value on a recurring basis	3,475,959,000		3,145,457,000
Total derivatives	97,179,000		32,379,000
Total liabilities at fair value	97,179,000		32,379,000
Measured on a Recurring Basis | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Loans held-for-sale	0		0
Loan servicing rights	60,658,000		71,013,000
Total derivatives	0		0
Total assets measured at fair value on a recurring basis	60,658,000		71,013,000
Total derivatives	0		0
Total liabilities at fair value	0		0
Measured on a Recurring Basis | Customer-initiated derivatives
Summary of assets measured at fair value on a recurring basis
Total derivatives	69,024,000		26,680,000
Total derivatives	70,707,000		27,664,000
Measured on a Recurring Basis | Customer-initiated derivatives | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Measured on a Recurring Basis | Customer-initiated derivatives | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	69,024,000		26,680,000
Total derivatives	70,707,000		27,664,000
Measured on a Recurring Basis | Customer-initiated derivatives | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Measured on a Recurring Basis | Forward contracts related to mortgage loans to be delivered for sale
Summary of assets measured at fair value on a recurring basis
Total derivatives	661,000		719,000
Measured on a Recurring Basis | Forward contracts related to mortgage loans to be delivered for sale | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Measured on a Recurring Basis | Forward contracts related to mortgage loans to be delivered for sale | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	661,000		719,000
Measured on a Recurring Basis | Forward contracts related to mortgage loans to be delivered for sale | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Measured on a Recurring Basis | Interest rate lock commitments
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,687,000		1,049,000
Measured on a Recurring Basis | Interest rate lock commitments | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Measured on a Recurring Basis | Interest rate lock commitments | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,687,000		1,049,000
Measured on a Recurring Basis | Interest rate lock commitments | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Measured on a Recurring Basis | Power Equity CD
Summary of assets measured at fair value on a recurring basis
Total derivatives	751,000		718,000
Total derivatives	751,000		718,000
Measured on a Recurring Basis | Power Equity CD | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Measured on a Recurring Basis | Power Equity CD | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	751,000		718,000
Total derivatives	751,000		718,000
Measured on a Recurring Basis | Power Equity CD | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Measured on a Recurring Basis | Risk management derivatives
Summary of assets measured at fair value on a recurring basis
Total derivatives	606,000		10,148,000
Total derivatives	25,060,000		3,278,000
Measured on a Recurring Basis | Risk management derivatives | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Measured on a Recurring Basis | Risk management derivatives | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	606,000		10,148,000
Total derivatives	25,060,000		3,278,000
Measured on a Recurring Basis | Risk management derivatives | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Total derivatives	0		0
Measured on a Recurring Basis | Government and government-sponsored enterprises
Summary of assets measured at fair value on a recurring basis
Carried at fair value	295,726,000		351,700,000
Measured on a Recurring Basis | Government and government-sponsored enterprises | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Government and government-sponsored enterprises | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	295,726,000		351,700,000
Measured on a Recurring Basis | Government and government-sponsored enterprises | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | State and political subdivisions
Summary of assets measured at fair value on a recurring basis
Carried at fair value	444,085,000		516,286,000
Measured on a Recurring Basis | State and political subdivisions | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | State and political subdivisions | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	444,085,000		516,286,000
Measured on a Recurring Basis | State and political subdivisions | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Residential mortgage-backed securities
Summary of assets measured at fair value on a recurring basis
Carried at fair value	353,622,000		213,428,000
Measured on a Recurring Basis | Residential mortgage-backed securities | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Residential mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	353,622,000		213,428,000
Measured on a Recurring Basis | Residential mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Collateralized mortgage obligations
Summary of assets measured at fair value on a recurring basis
Carried at fair value	1,939,695,000		1,601,298,000
Measured on a Recurring Basis | Collateralized mortgage obligations | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	1,939,695,000		1,601,298,000
Measured on a Recurring Basis | Collateralized mortgage obligations | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Corporate bonds
Summary of assets measured at fair value on a recurring basis
Carried at fair value	289,312,000		293,063,000
Measured on a Recurring Basis | Corporate bonds | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Corporate bonds | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	289,312,000		293,063,000
Measured on a Recurring Basis | Corporate bonds | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Trust preferred securities
Summary of assets measured at fair value on a recurring basis
Carried at fair value	47,432,000		46,057,000
Measured on a Recurring Basis | Trust preferred securities | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	0		0
Measured on a Recurring Basis | Trust preferred securities | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	47,432,000		46,057,000
Measured on a Recurring Basis | Trust preferred securities | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Carried at fair value	$ 0		$ 0

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis
Balance, beginning of period	$ 64,701	$ 68,837	$ 71,013	$ 63,841
Gains (losses): Recorded in earnings (realized):
Recorded in Net gain on sale of loans and other mortgage banking revenue	(6,152)	(757)	(14,597)	2,272
New originations	2,109	2,284	4,242	4,251
Balance, end of period	$ 60,658	$ 70,364	$ 60,658	$ 70,364

Fair Value Measurements - Aggre

Fair Value Measurements - Aggregate Fair Value, Contractual Balance, and Gain or Loss for Loans Held-For-Sale (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value Disclosures [Abstract]
Aggregate fair value	$ 33,019	$ 85,030
Contractual balance	31,799	82,080
Unrealized gain	$ 1,220	$ 2,950

Fair Value Measurements - Gains

Fair Value Measurements - Gains (Losses) from Loans Held-for-Sale (Details) - Loans Held For Sale - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	$ 6,069	$ 4,952	$ 10,777	$ 6,136
Interest income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	336	445	969	821
Change in fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	345	484	(1,730)	(216)
Net gain on sale of loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	$ 5,388	$ 4,023	$ 11,538	$ 5,531

Fair Value Measurements - Textu

Fair Value Measurements - Textual (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Fair Value Measurements (Textual) [Abstract]
Impairment of goodwill	$ 0	$ 0
Core deposit intangible assets
Fair Value Measurements (Textual) [Abstract]
Impairment valuation allowance	$ 0	0
Minimum | Core deposit intangible assets
Fair Value Measurements (Textual) [Abstract]
Expected life of intangible assets	10 years
Maximum | Core deposit intangible assets
Fair Value Measurements (Textual) [Abstract]
Expected life of intangible assets	15 years
Loans Held For Sale
Fair Value Measurements (Textual) [Abstract]
Loans held for sale that were on nonaccrual status	$ 0	0
Loans held for sale that were 90 days past due and on accrual status	$ 0	0
Total Impaired Loans | Minimum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	20.00%
Total Impaired Loans | Maximum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	30.00%
Other Real Estate and Repossessed Assets | Minimum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	20.00%
Other Real Estate and Repossessed Assets | Maximum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	30.00%
Measured on a Recurring Basis
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	$ 3,536,617,000	3,216,470,000
Fair Value Measurements (Textual) [Abstract]
Liabilities recorded at fair value	97,179,000	32,379,000
Measured on a Nonrecurring Basis
Fair Value Measurements (Textual) [Abstract]
Liabilities recorded at fair value	$ 0	$ 0

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Assets on a Nonrecurring Basis (Details) - Nonrecurring - Significant Unobservable Inputs (Level 3) $ in Thousands	Jun. 30, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	$ 79,649	$ 64,130
Impaired loans
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	76,186	63,247
Other real estate and repossessed assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Assets, fair value disclosure	$ 3,463	$ 883
Discount rate | Minimum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired originated loans, measurement input	0.20
Other real estate assets, measurement input	0.20
Discount rate | Maximum
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired originated loans, measurement input	0.30
Other real estate assets, measurement input	0.30

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Investment securities:
Held-to-maturity	$ 575,502	$ 618,672
Level 3 | Nonrecurring
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	79,649	64,130
Level 3 | Nonrecurring | Impaired loans
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, fair value disclosure	76,186	63,247
Carrying Amount | Level 2
Investment securities:
Held-to-maturity	565,546	623,599
Financial liabilities:
Time deposits	4,360,014	4,074,248
Collateralized customer deposits	291,671	382,687
Short-term borrowings	2,615,000	2,035,000
Long-term borrowings	426,069	426,002
Carrying Amount | Level 3
Investment securities:
Held-to-maturity	500	500
Net loans	15,745,936	15,159,795
Fair Value | Level 2
Investment securities:
Held-to-maturity	575,042	618,232
Financial liabilities:
Time deposits	4,354,554	4,041,212
Collateralized customer deposits	291,513	382,370
Short-term borrowings	2,614,777	2,034,719
Long-term borrowings	431,043	423,258
Fair Value | Level 3
Investment securities:
Held-to-maturity	460	440
Net loans	$ 15,717,256	$ 14,907,789

Investment Securities - Availab

Investment Securities - Available-For-Sale Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Total debt securities available-for-sale
Amortized Cost	$ 3,347,679
Unrealized Gains	35,738
Unrealized Losses	13,545
Fair Value	3,369,872
Total
Amortized Cost	3,347,679	$ 3,069,645
Unrealized Gains		5,601
Unrealized Losses		53,414
Total	3,369,872	3,021,832
Government and government-sponsored enterprises
Total debt securities available-for-sale
Amortized Cost	297,284	354,342
Unrealized Gains	378	713
Unrealized Losses	1,936	3,355
Fair Value	295,726	351,700
State and political subdivisions
Total debt securities available-for-sale
Amortized Cost	428,365	523,178
Unrealized Gains	15,845	1,141
Unrealized Losses	125	8,033
Fair Value	444,085	516,286
Residential mortgage-backed securities
Total debt securities available-for-sale
Amortized Cost	351,790	216,990
Unrealized Gains	2,807	261
Unrealized Losses	975	3,823
Fair Value	353,622	213,428
Collateralized mortgage obligations
Total debt securities available-for-sale
Amortized Cost	1,930,699	1,623,415
Unrealized Gains	14,869	2,903
Unrealized Losses	5,873	25,020
Fair Value	1,939,695	1,601,298
Corporate bonds
Total debt securities available-for-sale
Amortized Cost	291,869	304,243
Unrealized Gains	1,337	259
Unrealized Losses	3,894	11,439
Fair Value	289,312	293,063
Trust preferred securities
Total debt securities available-for-sale
Amortized Cost	47,672	47,477
Unrealized Gains	502	324
Unrealized Losses	742	1,744
Fair Value	$ 47,432	$ 46,057

Investment Securities - Held-To

Investment Securities - Held-To-Maturity Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Held-to-maturity Securities
Amortized Cost	$ 566,046	$ 624,099
Unrealized Gains	10,576	2,548
Unrealized Losses	1,120	7,975
Held-to-maturity, fair value	575,502	618,672
State and political subdivisions
Held-to-maturity Securities
Amortized Cost	565,546	623,599
Unrealized Gains	10,576	2,548
Unrealized Losses	1,080	7,915
Held-to-maturity, fair value	575,042	618,232
Trust preferred securities
Held-to-maturity Securities
Amortized Cost	500	500
Unrealized Gains	0	0
Unrealized Losses	40	60
Held-to-maturity, fair value	$ 460	$ 440

Investment Securities - Gains a

Investment Securities - Gains and (Losses) Recognized in Earnings (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)security	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)security	Jun. 30, 2018USD ($)
Investments, Debt and Equity Securities [Abstract]
Securities in unrealized loss positions, qualitative disclosure, number of positions (in security) | security	512		512
Proceeds	$ 133,829	$ 4,215	$ 205,331	$ 4,215
Gross gains	4,180	42	4,732	42
Gross losses	$ (20)	$ (39)	$ (485)	$ (39)

Investment Securities - Maturit

Investment Securities - Maturities of Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Investment Securities Available-for-Sale: Amortized Cost
Due in one year or less	$ 779,977
Due after one year through five years	1,292,316
Due after five years through ten years	812,375
Due after ten years	463,011
Amortized Cost	3,347,679	$ 3,069,645
Investment Securities Available-for-Sale: Fair Value
Due in one year or less	784,061
Due after one year through five years	1,297,464
Due after five years through ten years	809,765
Due after ten years	478,582
Total	3,369,872	3,021,832
Investment Securities Held-to-Maturity: Amortized Cost
Due in one year or less	55,592
Due after one year through five years	207,221
Due after five years through ten years	138,384
Due after ten years	164,849
Amortized Cost	566,046	624,099
Investment Securities Held-to-Maturity: Fair Value
Due in one year or less	55,657
Due after one year through five years	209,710
Due after five years through ten years	142,283
Due after ten years	167,852
Total	575,502	618,672
Collateral Pledged
Investment Securities Held-to-Maturity: Amortized Cost
Amortized Cost	$ 897,000	$ 1,050,000

Investment Securities - Gross U

Investment Securities - Gross Unrealized Losses (Details) $ in Thousands	Jun. 30, 2019USD ($)security	Dec. 31, 2018USD ($)
Schedule of Investments [Line Items]
Total number of securities, available-for-sale and held-to-maturity (in security) | security	1,912
Securities in unrealized loss positions, qualitative disclosure, number of positions (in security) | security	512
Fair Value
Less Than 12 Months	$ 369,846	$ 1,078,804
12 Months or More	1,097,973	1,605,905
Total	1,467,819	2,684,709
Gross Unrealized Losses
Less Than 12 Months	2,659	16,485
12 Months or More	12,006	44,904
Total	14,665	61,389
Government and government-sponsored enterprises
Fair Value
Less Than 12 Months	38,077	167,164
12 Months or More	171,701	62,200
Total	209,778	229,364
Gross Unrealized Losses
Less Than 12 Months	74	1,672
12 Months or More	1,862	1,683
Total	1,936	3,355
State and political subdivisions
Fair Value
Less Than 12 Months	10,105	190,551
12 Months or More	242,873	657,327
Total	252,978	847,878
Gross Unrealized Losses
Less Than 12 Months	15	1,932
12 Months or More	1,190	14,016
Total	1,205	15,948
Residential mortgage-backed securities
Fair Value
Less Than 12 Months	14,778	20,679
12 Months or More	102,387	123,757
Total	117,165	144,436
Gross Unrealized Losses
Less Than 12 Months	17	85
12 Months or More	958	3,738
Total	975	3,823
Collateralized mortgage obligations
Fair Value
Less Than 12 Months	229,853	496,356
12 Months or More	464,641	656,208
Total	694,494	1,152,564
Gross Unrealized Losses
Less Than 12 Months	1,684	5,268
12 Months or More	4,189	19,752
Total	5,873	25,020
Corporate bonds
Fair Value
Less Than 12 Months	52,131	169,431
12 Months or More	113,659	103,688
Total	165,790	273,119
Gross Unrealized Losses
Less Than 12 Months	269	5,888
12 Months or More	3,625	5,551
Total	3,894	11,439
Trust preferred securities
Fair Value
Less Than 12 Months	24,902	34,623
12 Months or More	2,712	2,725
Total	27,614	37,348
Gross Unrealized Losses
Less Than 12 Months	600	1,640
12 Months or More	182	164
Total	$ 782	$ 1,804

Loans - Textual (Details)

Loans - Textual (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)executive	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)segmenttenantclass_of_loanexecutive	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of portfolio segment (in segment) | segment			2
Number of classes of loans (in class of loan) | class_of_loan			6
Number of minimum tenants under lease of non-owner occupied commercial real estate (in tenant) | tenant			1
Minimum value of loan that requires regional loan committee approval	$ 3,000		$ 3,000
Maximum value of loan that requires regional loan committee approval	7,000		7,000
Total troubled debt restructurings	77,776		77,776		$ 73,655
Residential mortgage loans in process of foreclosure	3,600		3,600		4,500
Commitment to lend additional funds to borrowers whose terms have been modified in TDRs	4,300		4,300		3,200
Loans held-for-sale, at fair value	33,019		33,019		85,030
Proceeds from sales of loans	196,900	$ 202,100	392,730	$ 392,570
Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	29,923		29,923		28,075
Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	47,853		47,853		45,580
Consumer loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	15,701		15,701		16,804
Consumer loan portfolio | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	3,397		3,397		3,732
Consumer loan portfolio | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	12,304		12,304		13,072
Commercial loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	62,075		62,075		56,851
Commercial loan portfolio | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	26,526		26,526		24,343
Commercial loan portfolio | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	35,549		$ 35,549		$ 32,508
Land development loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Maximum period for payment of loan			12 months
Residential mortgage
Accounts, Notes, Loans and Financing Receivable [Line Items]
Period for loan secured under real estate residential security			15 years
Loan-to-value ratio at the time of origination			80.00%
Commercial | Commercial loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum value of loan requires group loan authority approval	1,250		$ 1,250
Maximum value of loan requires senior officer approval	$ 3,000		$ 3,000
Number of bank executives and senior officers with credit decision limits similar to group loan authorities (in executive) | executive	6		6
Maximum value of loan requires executive and senior officer approval	$ 8,000		$ 8,000
Minimum value of loan requires group loan authority approval	$ 7,000		$ 7,000

Loans - Summary of Loans (Detai

Loans - Summary of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Summary of loans under portfolio
Total loans	$ 15,861,903	$ 15,269,779
Deferred income	27,200	19,700
Commercial loan portfolio
Summary of loans under portfolio
Total loans	9,895,855	9,511,867
Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	4,347,885	4,002,568
Commercial loan portfolio | Total commercial real estate
Summary of loans under portfolio
Total loans	4,847,200	4,912,087
Commercial loan portfolio | Real estate construction and land development
Summary of loans under portfolio
Total loans	700,770	597,212
Consumer loan portfolio
Summary of loans under portfolio
Total loans	5,966,048	5,757,912
Consumer loan portfolio | Residential mortgage
Summary of loans under portfolio
Total loans	3,666,613	3,458,666
Consumer loan portfolio | Consumer installment
Summary of loans under portfolio
Total loans	1,552,835	1,521,074
Consumer loan portfolio | Home equity
Summary of loans under portfolio
Total loans	746,600	778,172
Originated
Summary of loans under portfolio
Total loans	12,871,110	11,844,756
Originated | Commercial
Summary of loans under portfolio
Total loans	3,752,528	3,287,087
Originated | Total commercial real estate
Summary of loans under portfolio
Total loans	3,622,488	3,520,157
Originated | Real estate construction and land development
Summary of loans under portfolio
Total loans	671,773	566,726
Originated | Residential mortgage
Summary of loans under portfolio
Total loans	2,722,019	2,407,305
Originated | Consumer installment
Summary of loans under portfolio
Total loans	1,497,467	1,451,352
Originated | Home equity
Summary of loans under portfolio
Total loans	604,835	612,129
Originated | Commercial loan portfolio
Summary of loans under portfolio
Total loans	8,046,789	7,373,970
Originated | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	3,752,528	3,287,087
Originated | Commercial loan portfolio | Total commercial real estate
Summary of loans under portfolio
Total loans	3,622,488	3,520,157
Originated | Commercial loan portfolio | Real estate construction and land development
Summary of loans under portfolio
Total loans	671,773	566,726
Originated | Consumer loan portfolio
Summary of loans under portfolio
Total loans	4,824,321	4,470,786
Originated | Consumer loan portfolio | Residential mortgage
Summary of loans under portfolio
Total loans	2,722,019	2,407,305
Originated | Consumer loan portfolio | Consumer installment
Summary of loans under portfolio
Total loans	1,497,467	1,451,352
Originated | Consumer loan portfolio | Home equity
Summary of loans under portfolio
Total loans	604,835	612,129
Acquired
Summary of loans under portfolio
Total loans	2,990,793	3,425,023
Acquired | Commercial loan portfolio
Summary of loans under portfolio
Total loans	1,849,066	2,137,897
Acquired | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	595,357	715,481
Acquired | Commercial loan portfolio | Total commercial real estate
Summary of loans under portfolio
Total loans	1,224,712	1,391,930
Acquired | Commercial loan portfolio | Real estate construction and land development
Summary of loans under portfolio
Total loans	28,997	30,486
Acquired | Consumer loan portfolio
Summary of loans under portfolio
Total loans	1,141,727	1,287,126
Acquired | Consumer loan portfolio | Residential mortgage
Summary of loans under portfolio
Total loans	944,594	1,051,361
Acquired | Consumer loan portfolio | Consumer installment
Summary of loans under portfolio
Total loans	55,368	69,722
Acquired | Consumer loan portfolio | Home equity
Summary of loans under portfolio
Total loans	141,765	166,043
Owner-occupied | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	2,024,561	2,059,557
Owner-occupied | Originated | Commercial
Summary of loans under portfolio
Total loans	1,528,802	1,513,532
Owner-occupied | Originated | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	1,528,802	1,513,532
Owner-occupied | Acquired | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	495,759	546,025
Non-owner occupied | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	2,772,677	2,785,020
Non-owner occupied | Originated | Commercial
Summary of loans under portfolio
Total loans	2,056,531	1,966,330
Non-owner occupied | Originated | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	2,056,531	1,966,330
Non-owner occupied | Acquired | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	716,146	818,690
Vacant land | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	49,962	67,510
Vacant land | Originated | Commercial
Summary of loans under portfolio
Total loans	37,155	40,295
Vacant land | Originated | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	37,155	40,295
Vacant land | Acquired | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	$ 12,807	$ 27,215

Loans - Activity for Accretable

Loans - Activity for Accretable Yield (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Activity for accretable yield
Balance at beginning of period	$ 602,664	$ 868,698	$ 647,325	$ 926,897
Accretion recognized in interest income	(47,421)	(56,900)	(96,566)	(115,461)
Net reclassification (to) from nonaccretable difference	3,547	(31,034)	8,031	(30,672)
Balance at end of period	558,790	780,764	558,790	780,764
Talmer
Activity for accretable yield
Balance at beginning of period	469,713	685,830	505,332	731,353
Accretion recognized in interest income	(36,730)	(42,136)	(74,761)	(84,776)
Net reclassification (to) from nonaccretable difference	730	(27,526)	3,142	(30,409)
Balance at end of period	433,713	616,168	433,713	616,168
Lake Michigan
Activity for accretable yield
Balance at beginning of period	68,995	90,156	73,132	95,124
Accretion recognized in interest income	(5,291)	(6,302)	(10,842)	(13,060)
Net reclassification (to) from nonaccretable difference	409	(3,412)	1,823	(1,622)
Balance at end of period	64,113	80,442	64,113	80,442
Monarch
Activity for accretable yield
Balance at beginning of period	16,967	21,154	17,832	22,496
Accretion recognized in interest income	(852)	(962)	(1,626)	(2,118)
Net reclassification (to) from nonaccretable difference	750	(61)	659	(247)
Balance at end of period	16,865	20,131	16,865	20,131
North-western
Activity for accretable yield
Balance at beginning of period	38,644	55,400	41,455	60,814
Accretion recognized in interest income	(3,214)	(4,618)	(6,634)	(9,522)
Net reclassification (to) from nonaccretable difference	745	(1,051)	1,354	(1,561)
Balance at end of period	36,175	49,731	36,175	49,731
OAK
Activity for accretable yield
Balance at beginning of period	8,345	16,158	9,574	17,110
Accretion recognized in interest income	(1,334)	(2,882)	(2,703)	(5,985)
Net reclassification (to) from nonaccretable difference	913	1,016	1,053	3,167
Balance at end of period	$ 7,924	$ 14,292	$ 7,924	$ 14,292

Loans - Commercial Loans by Ris

Loans - Commercial Loans by Risk Rating Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	$ 15,861,903	$ 15,269,779
Originated
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	12,871,110	11,844,756
Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,752,528	3,287,087
Originated | Total commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,622,488	3,520,157
Originated | Real estate construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	671,773	566,726
Acquired
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,990,793	3,425,023
Commercial loan portfolio
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	9,895,855	9,511,867
Commercial loan portfolio | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	9,354,289	8,998,284
Commercial loan portfolio | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	282,192	283,400
Commercial loan portfolio | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	250,024	225,924
Commercial loan portfolio | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	9,350	4,259
Commercial loan portfolio | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	4,347,885	4,002,568
Commercial loan portfolio | Total commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	4,847,200	4,912,087
Commercial loan portfolio | Real estate construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	700,770	597,212
Commercial loan portfolio | Originated
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	8,046,789	7,373,970
Commercial loan portfolio | Originated | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	7,689,269	7,045,203
Commercial loan portfolio | Originated | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	158,331	164,802
Commercial loan portfolio | Originated | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	192,055	159,733
Commercial loan portfolio | Originated | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	7,134	4,232
Commercial loan portfolio | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,752,528	3,287,087
Commercial loan portfolio | Originated | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,513,993	3,118,894
Commercial loan portfolio | Originated | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	123,194	87,222
Commercial loan portfolio | Originated | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	108,373	77,036
Commercial loan portfolio | Originated | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	6,968	3,935
Commercial loan portfolio | Originated | Total commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,622,488	3,520,157
Commercial loan portfolio | Originated | Total commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,511,154	3,369,269
Commercial loan portfolio | Originated | Total commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	31,525	71,472
Commercial loan portfolio | Originated | Total commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	79,643	79,119
Commercial loan portfolio | Originated | Total commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	166	297
Commercial loan portfolio | Originated | Real estate construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	671,773	566,726
Commercial loan portfolio | Originated | Real estate construction and land development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	664,122	557,040
Commercial loan portfolio | Originated | Real estate construction and land development | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,612	6,108
Commercial loan portfolio | Originated | Real estate construction and land development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	4,039	3,578
Commercial loan portfolio | Originated | Real estate construction and land development | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0	0
Commercial loan portfolio | Acquired
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,849,066	2,137,897
Commercial loan portfolio | Acquired | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,665,020	1,953,081
Commercial loan portfolio | Acquired | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	123,861	118,598
Commercial loan portfolio | Acquired | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	57,969	66,191
Commercial loan portfolio | Acquired | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,216	27
Commercial loan portfolio | Acquired | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	595,357	715,481
Commercial loan portfolio | Acquired | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	505,823	655,883
Commercial loan portfolio | Acquired | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	62,253	36,809
Commercial loan portfolio | Acquired | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	25,512	22,773
Commercial loan portfolio | Acquired | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,769	16
Commercial loan portfolio | Acquired | Total commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,224,712	1,391,930
Commercial loan portfolio | Acquired | Total commercial real estate | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,130,482	1,267,950
Commercial loan portfolio | Acquired | Total commercial real estate | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	61,566	81,692
Commercial loan portfolio | Acquired | Total commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	32,217	42,277
Commercial loan portfolio | Acquired | Total commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	447	11
Commercial loan portfolio | Acquired | Real estate construction and land development
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	28,997	30,486
Commercial loan portfolio | Acquired | Real estate construction and land development | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	28,715	29,248
Commercial loan portfolio | Acquired | Real estate construction and land development | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	42	97
Commercial loan portfolio | Acquired | Real estate construction and land development | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	240	1,141
Commercial loan portfolio | Acquired | Real estate construction and land development | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0	0
Owner-occupied | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,528,802	1,513,532
Owner-occupied | Commercial loan portfolio | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,024,561	2,059,557
Owner-occupied | Commercial loan portfolio | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,528,802	1,513,532
Owner-occupied | Commercial loan portfolio | Originated | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,452,031	1,430,948
Owner-occupied | Commercial loan portfolio | Originated | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	25,913	32,056
Owner-occupied | Commercial loan portfolio | Originated | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	50,697	50,286
Owner-occupied | Commercial loan portfolio | Originated | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	161	242
Owner-occupied | Commercial loan portfolio | Acquired | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	495,759	546,025
Owner-occupied | Commercial loan portfolio | Acquired | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	462,266	500,072
Owner-occupied | Commercial loan portfolio | Acquired | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	18,226	28,909
Owner-occupied | Commercial loan portfolio | Acquired | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	14,835	17,033
Owner-occupied | Commercial loan portfolio | Acquired | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	432	11
Non-owner occupied | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,056,531	1,966,330
Non-owner occupied | Commercial loan portfolio | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,772,677	2,785,020
Non-owner occupied | Commercial loan portfolio | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,056,531	1,966,330
Non-owner occupied | Commercial loan portfolio | Originated | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,023,577	1,901,822
Non-owner occupied | Commercial loan portfolio | Originated | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	5,516	39,416
Non-owner occupied | Commercial loan portfolio | Originated | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	27,433	25,092
Non-owner occupied | Commercial loan portfolio | Originated | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	5	0
Non-owner occupied | Commercial loan portfolio | Acquired | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	716,146	818,690
Non-owner occupied | Commercial loan portfolio | Acquired | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	655,602	740,900
Non-owner occupied | Commercial loan portfolio | Acquired | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	43,147	52,546
Non-owner occupied | Commercial loan portfolio | Acquired | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	17,382	25,244
Non-owner occupied | Commercial loan portfolio | Acquired | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	15	0
Vacant land | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	37,155	40,295
Vacant land | Commercial loan portfolio | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	49,962	67,510
Vacant land | Commercial loan portfolio | Originated | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	37,155	40,295
Vacant land | Commercial loan portfolio | Originated | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	35,546	36,499
Vacant land | Commercial loan portfolio | Originated | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	96	0
Vacant land | Commercial loan portfolio | Originated | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,513	3,741
Vacant land | Commercial loan portfolio | Originated | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0	55
Vacant land | Commercial loan portfolio | Acquired | Commercial
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	12,807	27,215
Vacant land | Commercial loan portfolio | Acquired | Commercial | Pass
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	12,614	26,978
Vacant land | Commercial loan portfolio | Acquired | Commercial | Special Mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	193	237
Vacant land | Commercial loan portfolio | Acquired | Commercial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	0	0
Vacant land | Commercial loan portfolio | Acquired | Commercial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	$ 0	$ 0

Loans - Consumer Loans by Risk

Loans - Consumer Loans by Risk Rating Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	$ 15,861,903	$ 15,269,779
Originated
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	12,871,110	11,844,756
Originated | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,722,019	2,407,305
Originated | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,497,467	1,451,352
Originated | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	604,835	612,129
Acquired
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,990,793	3,425,023
Consumer loan portfolio
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	5,966,048	5,757,912
Consumer loan portfolio | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,666,613	3,458,666
Consumer loan portfolio | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,552,835	1,521,074
Consumer loan portfolio | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	746,600	778,172
Consumer loan portfolio | Originated
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	4,824,321	4,470,786
Consumer loan portfolio | Originated | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,722,019	2,407,305
Consumer loan portfolio | Originated | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,497,467	1,451,352
Consumer loan portfolio | Originated | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	604,835	612,129
Consumer loan portfolio | Originated | Performing
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	4,811,787	4,457,918
Consumer loan portfolio | Originated | Performing | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	2,714,383	2,399,317
Consumer loan portfolio | Originated | Performing | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,496,056	1,450,076
Consumer loan portfolio | Originated | Performing | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	601,348	608,525
Consumer loan portfolio | Originated | Nonperforming
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	12,534	12,868
Consumer loan portfolio | Originated | Nonperforming | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	7,636	7,988
Consumer loan portfolio | Originated | Nonperforming | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,411	1,276
Consumer loan portfolio | Originated | Nonperforming | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	3,487	3,604
Consumer loan portfolio | Acquired
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	1,141,727	1,287,126
Consumer loan portfolio | Acquired | Residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	944,594	1,051,361
Consumer loan portfolio | Acquired | Consumer installment
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	55,368	69,722
Consumer loan portfolio | Acquired | Home equity
Financing Receivable, Credit Quality Indicator [Line Items]
Total loans	$ 141,765	$ 166,043

Loans - Nonperforming Loans (De

Loans - Nonperforming Loans (Details) - Nonperforming - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Summary of nonperforming loans
Total nonaccrual loans	$ 97,696	$ 85,433
Other real estate owned and repossessed assets	8,267	6,256
Total nonperforming assets	105,963	91,689
Commercial
Summary of nonperforming loans
Total nonaccrual loans	37,762	30,139
Total commercial real estate
Summary of nonperforming loans
Total nonaccrual loans	43,899	42,414
Real estate construction and land development
Summary of nonperforming loans
Total nonaccrual loans	3,501	12
Residential mortgage
Summary of nonperforming loans
Total nonaccrual loans	7,636	7,988
Consumer installment
Summary of nonperforming loans
Total nonaccrual loans	1,411	1,276
Home equity
Summary of nonperforming loans
Total nonaccrual loans	3,487	3,604
Owner-occupied | Commercial
Summary of nonperforming loans
Total nonaccrual loans	20,814	16,056
Non-owner occupied | Commercial
Summary of nonperforming loans
Total nonaccrual loans	21,639	23,021
Vacant land | Commercial
Summary of nonperforming loans
Total nonaccrual loans	$ 1,446	$ 3,337

Loans - Aging Status of Loans (

Loans - Aging Status of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Schedule representing the aging status of the recorded investment in loans by classes
Total loans	$ 15,861,903	$ 15,269,779
Originated Portfolio
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	37,241	35,381
Nonaccrual Loans	97,696	85,433
Current	12,736,173	11,723,942
Total loans	12,871,110	11,844,756
Originated Portfolio | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	37,095	33,954
Originated Portfolio | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	146	1,427
Originated Portfolio | Commercial
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	19,304	16,835
Nonaccrual Loans	37,762	30,139
Current	3,695,462	3,240,113
Total loans	3,752,528	3,287,087
Originated Portfolio | Commercial | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	19,158	16,835
Originated Portfolio | Commercial | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	146	0
Originated Portfolio | Total commercial real estate
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	5,583	7,549
Nonaccrual Loans	43,899	42,414
Current	3,573,006	3,470,194
Total loans	3,622,488	3,520,157
Originated Portfolio | Total commercial real estate | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	5,583	6,610
Originated Portfolio | Total commercial real estate | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	939
Originated Portfolio | Real estate construction and land development
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	538	247
Nonaccrual Loans	3,501	12
Current	667,734	566,467
Total loans	671,773	566,726
Originated Portfolio | Real estate construction and land development | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	538	247
Originated Portfolio | Real estate construction and land development | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	0
Originated Portfolio | Residential mortgage
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	6,183	1,688
Nonaccrual Loans	7,636	7,988
Current	2,708,200	2,397,629
Total loans	2,722,019	2,407,305
Originated Portfolio | Residential mortgage | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	6,183	1,688
Originated Portfolio | Residential mortgage | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	0
Originated Portfolio | Consumer installment
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	3,076	4,731
Nonaccrual Loans	1,411	1,276
Current	1,492,980	1,445,345
Total loans	1,497,467	1,451,352
Originated Portfolio | Consumer installment | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	3,076	4,731
Originated Portfolio | Consumer installment | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	0
Originated Portfolio | Home equity
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	2,557	4,331
Nonaccrual Loans	3,487	3,604
Current	598,791	604,194
Total loans	604,835	612,129
Originated Portfolio | Home equity | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	2,557	3,843
Originated Portfolio | Home equity | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	488
Owner-occupied | Originated Portfolio | Commercial
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	3,368	4,709
Nonaccrual Loans	20,814	16,056
Current	1,504,620	1,492,767
Total loans	1,528,802	1,513,532
Owner-occupied | Originated Portfolio | Commercial | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	3,368	4,657
Owner-occupied | Originated Portfolio | Commercial | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	52
Non-owner occupied | Originated Portfolio | Commercial
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	1,714	2,680
Nonaccrual Loans	21,639	23,021
Current	2,033,178	1,940,629
Total loans	2,056,531	1,966,330
Non-owner occupied | Originated Portfolio | Commercial | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	1,714	1,793
Non-owner occupied | Originated Portfolio | Commercial | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	0	887
Vacant land | Originated Portfolio | Commercial
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	501	160
Nonaccrual Loans	1,446	3,337
Current	35,208	36,798
Total loans	37,155	40,295
Vacant land | Originated Portfolio | Commercial | 30-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	501	160
Vacant land | Originated Portfolio | Commercial | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Loans Past Due and Still Accruing	$ 0	$ 0

Loans - Impaired Loans by Class

Loans - Impaired Loans by Class (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 87,204	$ 70,051
Unpaid Principal Balance	94,274	75,511
Related Valuation Allowance	11,018	6,804
Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	58,497	60,822
Unpaid Principal Balance	61,586	64,378
Related Valuation Allowance	0	0
Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	145,701	130,873
Unpaid Principal Balance	155,860	139,889
Related Valuation Allowance	11,018	6,804
Commercial | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	28,732	20,957
Unpaid Principal Balance	31,556	23,781
Related Valuation Allowance	5,805	3,546
Commercial | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	28,775	25,093
Unpaid Principal Balance	29,586	25,934
Related Valuation Allowance	0	0
Commercial | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	57,507	46,050
Unpaid Principal Balance	61,142	49,715
Related Valuation Allowance	5,805	3,546
Total commercial real estate | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	38,916	32,543
Unpaid Principal Balance	43,162	35,179
Related Valuation Allowance	3,593	1,917
Total commercial real estate | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	20,660	26,208
Unpaid Principal Balance	22,938	28,923
Related Valuation Allowance	0	0
Total commercial real estate | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	59,576	58,751
Unpaid Principal Balance	66,100	64,102
Related Valuation Allowance	3,593	1,917
Real estate construction and land development | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	3,612	126
Unpaid Principal Balance	3,612	126
Related Valuation Allowance	365	11
Real estate construction and land development | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	164	111
Unpaid Principal Balance	164	111
Related Valuation Allowance	0	0
Real estate construction and land development | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	3,776	237
Unpaid Principal Balance	3,776	237
Related Valuation Allowance	365	11
Residential mortgage | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	10,060	10,867
Unpaid Principal Balance	10,060	10,867
Related Valuation Allowance	790	816
Residential mortgage | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	7,235	7,537
Unpaid Principal Balance	7,235	7,537
Related Valuation Allowance	0	0
Residential mortgage | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	17,295	18,404
Unpaid Principal Balance	17,295	18,404
Related Valuation Allowance	790	816
Consumer installment | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,594	1,126
Unpaid Principal Balance	1,594	1,126
Related Valuation Allowance	109	186
Consumer installment | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	7	377
Unpaid Principal Balance	7	377
Related Valuation Allowance	0	0
Consumer installment | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,601	1,503
Unpaid Principal Balance	1,601	1,503
Related Valuation Allowance	109	186
Home equity | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,290	4,432
Unpaid Principal Balance	4,290	4,432
Related Valuation Allowance	356	328
Home equity | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,656	1,496
Unpaid Principal Balance	1,656	1,496
Related Valuation Allowance	0	0
Home equity | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	5,946	5,928
Unpaid Principal Balance	5,946	5,928
Related Valuation Allowance	356	328
Owner-occupied | Commercial | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	20,050	14,702
Unpaid Principal Balance	22,193	16,519
Related Valuation Allowance	2,168	1,359
Owner-occupied | Commercial | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	12,057	10,971
Unpaid Principal Balance	12,895	11,601
Related Valuation Allowance	0	0
Owner-occupied | Commercial | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	32,107	25,673
Unpaid Principal Balance	35,088	28,120
Related Valuation Allowance	2,168	1,359
Non-owner occupied | Commercial | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	18,080	16,833
Unpaid Principal Balance	19,966	17,452
Related Valuation Allowance	1,366	462
Non-owner occupied | Commercial | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	7,827	12,412
Unpaid Principal Balance	8,339	13,411
Related Valuation Allowance	0	0
Non-owner occupied | Commercial | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	25,907	29,245
Unpaid Principal Balance	28,305	30,863
Related Valuation Allowance	1,366	462
Vacant land | Commercial | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	786	1,008
Unpaid Principal Balance	1,003	1,208
Related Valuation Allowance	59	96
Vacant land | Commercial | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	776	2,825
Unpaid Principal Balance	1,704	3,911
Related Valuation Allowance	0	0
Vacant land | Commercial | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,562	3,833
Unpaid Principal Balance	2,707	5,119
Related Valuation Allowance	$ 59	$ 96

Loans - Impaired Loans (Details

Loans - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Average recorded investment
Impaired loans with a valuation allowance	$ 72,761	$ 51,526	$ 71,713	$ 55,997
Impaired loans with no related valuation allowance	69,158	59,219	68,097	55,036
Total impaired loans	141,919	110,745	139,810	111,033
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	359	359	750	769
Impaired loans with no related valuation allowance	368	295	688	542
Total impaired loans	727	654	1,438	1,311
Commercial
Average recorded investment
Impaired loans with a valuation allowance	26,587	18,139	24,109	19,271
Impaired loans with no related valuation allowance	27,865	20,078	27,510	19,102
Total impaired loans	54,452	38,217	51,619	38,373
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	93	111	179	276
Impaired loans with no related valuation allowance	201	147	384	242
Total impaired loans	294	258	563	518
Total commercial real estate
Average recorded investment
Impaired loans with a valuation allowance	27,353	16,503	29,473	19,070
Impaired loans with no related valuation allowance	31,927	27,544	30,701	25,920
Total impaired loans	59,280	44,047	60,174	44,990
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	141	108	319	216
Impaired loans with no related valuation allowance	131	119	231	240
Total impaired loans	272	227	550	456
Real estate construction and land development
Average recorded investment
Impaired loans with a valuation allowance	3,730	243	3,174	234
Impaired loans with no related valuation allowance	102	1,994	76	1,051
Total impaired loans	3,832	2,237	3,250	1,285
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	2	2	4	4
Impaired loans with no related valuation allowance	2	2	4	3
Total impaired loans	4	4	8	7
Residential mortgage
Average recorded investment
Impaired loans with a valuation allowance	10,011	12,762	10,005	13,183
Impaired loans with no related valuation allowance	7,241	7,075	7,488	6,606
Total impaired loans	17,252	19,837	17,493	19,789
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	97	115	198	232
Impaired loans with no related valuation allowance	29	25	57	48
Total impaired loans	126	140	255	280
Consumer installment
Average recorded investment
Impaired loans with a valuation allowance	1,250	1,067	1,213	986
Impaired loans with no related valuation allowance	36	41	226	91
Total impaired loans	1,286	1,108	1,439	1,077
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	2	2	4	3
Impaired loans with no related valuation allowance	0	0	0	0
Total impaired loans	2	2	4	3
Home equity
Average recorded investment
Impaired loans with a valuation allowance	3,830	2,812	3,739	3,253
Impaired loans with no related valuation allowance	1,987	2,487	2,096	2,266
Total impaired loans	5,817	5,299	5,835	5,519
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	24	21	46	38
Impaired loans with no related valuation allowance	5	2	12	9
Total impaired loans	29	23	58	47
Owner-occupied | Total commercial real estate
Average recorded investment
Impaired loans with a valuation allowance	17,515	12,949	17,522	13,510
Impaired loans with no related valuation allowance	14,110	14,565	12,841	14,967
Total impaired loans	31,625	27,514	30,363	28,477
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	130	81	255	163
Impaired loans with no related valuation allowance	73	81	126	137
Total impaired loans	203	162	381	300
Non-owner occupied | Total commercial real estate
Average recorded investment
Impaired loans with a valuation allowance	9,050	2,246	11,055	3,058
Impaired loans with no related valuation allowance	16,677	9,539	16,073	8,349
Total impaired loans	25,727	11,785	27,128	11,407
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	9	10	54	21
Impaired loans with no related valuation allowance	58	38	105	103
Total impaired loans	67	48	159	124
Vacant land | Total commercial real estate
Average recorded investment
Impaired loans with a valuation allowance	788	1,308	896	2,502
Impaired loans with no related valuation allowance	1,140	3,440	1,787	2,604
Total impaired loans	1,928	4,748	2,683	5,106
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	2	17	10	32
Impaired loans with no related valuation allowance	0	0	0	0
Total impaired loans	$ 2	$ 17	$ 10	$ 32

Loans - Loan Modifications by C

Loans - Loan Modifications by Concession Type (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)loan	Jun. 30, 2018USD ($)loan	Jun. 30, 2019USD ($)loan	Jun. 30, 2018USD ($)loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 5,443	$ 1,968	$ 14,442	$ 5,946
Total number of loans (in loan) | loan	37	35	70	81
Pre-modification recorded investment	$ 5,540	$ 2,002	$ 14,792	$ 6,042
Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	433	1,337	3,857	2,702
Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	70	84	274	107
Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	1,345	516	1,815	2,363
Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	3,595	31	8,496	774
Commercial loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 4,611	$ 1,521	$ 13,188	$ 5,026
Total number of loans (in loan) | loan	19	19	36	40
Pre-modification recorded investment	$ 4,677	$ 1,544	$ 13,482	$ 5,061
Commercial loan portfolio | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	170	1,110	3,273	2,081
Commercial loan portfolio | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	12	0	115	0
Commercial loan portfolio | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	834	380	1,304	2,171
Commercial loan portfolio | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	3,595	31	8,496	774
Commercial loan portfolio | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 3,803	$ 958	$ 8,159	$ 3,187
Total number of loans (in loan) | loan	13	13	24	31
Pre-modification recorded investment	$ 3,818	$ 969	$ 8,386	$ 3,204
Commercial loan portfolio | Commercial | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	14	740	388	1,643
Commercial loan portfolio | Commercial | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	12	0	12	0
Commercial loan portfolio | Commercial | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	426	218	867	1,283
Commercial loan portfolio | Commercial | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	3,351	0	6,892	261
Commercial loan portfolio | Total commercial real estate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 808	$ 563	$ 5,029	$ 1,839
Total number of loans (in loan) | loan	6	6	12	9
Pre-modification recorded investment	$ 859	$ 575	$ 5,096	$ 1,857
Commercial loan portfolio | Total commercial real estate | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	156	370	2,885	438
Commercial loan portfolio | Total commercial real estate | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	0	103	0
Commercial loan portfolio | Total commercial real estate | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	408	162	437	888
Commercial loan portfolio | Total commercial real estate | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	244	31	1,604	513
Consumer loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 832	$ 447	$ 1,254	$ 920
Total number of loans (in loan) | loan	18	16	34	41
Pre-modification recorded investment	$ 863	$ 458	$ 1,310	$ 981
Consumer loan portfolio | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	263	227	584	621
Consumer loan portfolio | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	58	84	159	107
Consumer loan portfolio | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	511	136	511	192
Consumer loan portfolio | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Residential mortgage
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 411	$ 210	$ 653	$ 348
Total number of loans (in loan) | loan	4	3	6	7
Pre-modification recorded investment	$ 422	$ 215	$ 679	$ 357
Consumer loan portfolio | Residential mortgage | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	81	131	248	269
Consumer loan portfolio | Residential mortgage | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	40	75	40
Consumer loan portfolio | Residential mortgage | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	330	39	330	39
Consumer loan portfolio | Residential mortgage | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Consumer installment
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 67	$ 69	$ 139	$ 191
Total number of loans (in loan) | loan	6	9	17	25
Pre-modification recorded investment	$ 70	$ 72	$ 149	$ 200
Consumer loan portfolio | Consumer installment | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	15	15	61	86
Consumer loan portfolio | Consumer installment | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	39	44	65	67
Consumer loan portfolio | Consumer installment | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	13	10	13	38
Consumer loan portfolio | Consumer installment | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Home equity
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 354	$ 168	$ 462	$ 381
Total number of loans (in loan) | loan	8	4	11	9
Pre-modification recorded investment	$ 371	$ 171	$ 482	$ 424
Consumer loan portfolio | Home equity | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	167	81	275	266
Consumer loan portfolio | Home equity | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	19	0	19	0
Consumer loan portfolio | Home equity | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	168	87	168	115
Consumer loan portfolio | Home equity | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	0	0	0
Owner-occupied | Commercial loan portfolio | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 424	$ 563	$ 4,623	$ 1,771
Total number of loans (in loan) | loan	4	6	9	8
Pre-modification recorded investment	$ 436	$ 575	$ 4,649	$ 1,783
Owner-occupied | Commercial loan portfolio | Commercial | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	156	370	2,863	370
Owner-occupied | Commercial loan portfolio | Commercial | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	0	103	0
Owner-occupied | Commercial loan portfolio | Commercial | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	268	162	297	888
Owner-occupied | Commercial loan portfolio | Commercial | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0	$ 31	1,360	513
Non-owner occupied | Commercial loan portfolio | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 140		$ 140	$ 68
Total number of loans (in loan) | loan	1		1	1
Pre-modification recorded investment	$ 154		$ 154	$ 74
Non-owner occupied | Commercial loan portfolio | Commercial | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0		0	68
Non-owner occupied | Commercial loan portfolio | Commercial | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0		0	0
Non-owner occupied | Commercial loan portfolio | Commercial | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	140		140	0
Non-owner occupied | Commercial loan portfolio | Commercial | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0		0	$ 0
Vacant land | Commercial loan portfolio | Commercial
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 244		$ 266
Total number of loans (in loan) | loan	1		2
Pre-modification recorded investment	$ 269		$ 293
Vacant land | Commercial loan portfolio | Commercial | Principal deferral
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0		22
Vacant land | Commercial loan portfolio | Commercial | Principal reduction
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0		0
Vacant land | Commercial loan portfolio | Commercial | Interest rate
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	0		0
Vacant land | Commercial loan portfolio | Commercial | Forbearance agreement
Financing Receivable, Troubled Debt Restructuring [Line Items]
Post-modification recorded investment	$ 244		$ 244

Loans - Summary of TDRs (Detail

Loans - Summary of TDRs (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	$ 77,776	$ 73,655
Commercial loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	62,075	56,851
Consumer loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	15,701	16,804
Accruing TDRs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	47,853	45,580
Accruing TDRs | Commercial loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	35,549	32,508
Accruing TDRs | Consumer loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	12,304	13,072
Nonaccrual TDRs
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	29,923	28,075
Nonaccrual TDRs | Commercial loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	26,526	24,343
Nonaccrual TDRs | Consumer loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Total TDRs	$ 3,397	$ 3,732

Loans - TDRs with a Payment Def

Loans - TDRs with a Payment Default During the Period (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)loan	Jun. 30, 2018USD ($)loan	Jun. 30, 2019USD ($)loan	Jun. 30, 2018USD ($)loan
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans (in loan) | loan		9	2	11
Principal balance | $		$ 109	$ 29	$ 194
Commercial loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans (in loan) | loan	0	2	0	3
Principal balance | $	$ 0	$ 67	$ 0	$ 149
Consumer loan portfolio
Financing Receivable, Troubled Debt Restructuring [Line Items]
Number of loans (in loan) | loan	2	7	2	8
Principal balance | $	$ 29	$ 42	$ 29	$ 45

Loans - Allowance for Loan Loss

Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance			$ 109,984
Ending balance	$ 115,967		115,967
Allowance for loan losses
Loans individually evaluated for impairment					$ 11,018	$ 6,804
Loans collectively evaluated for impairment					104,949	102,760
Loans accounted for under ASC 310-30					0	420
Total allowance for loan losses	115,967		115,967		115,967	109,984
Recorded investment (loan balance)
Loans individually evaluated for impairment					145,701	130,873
Loans collectively evaluated for impairment					12,725,409	11,713,883
Loans acquired with deteriorated credit quality					2,990,793	3,425,023
Total loans					15,861,903	15,269,779
Commercial loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance			83,179
Ending balance	87,900		87,900
Allowance for loan losses
Loans individually evaluated for impairment					9,763	5,474
Loans collectively evaluated for impairment					78,137	77,285
Loans accounted for under ASC 310-30					0	420
Total allowance for loan losses	87,900		87,900		87,900	83,179
Recorded investment (loan balance)
Loans individually evaluated for impairment					120,859	105,038
Loans collectively evaluated for impairment					7,925,930	7,268,932
Loans acquired with deteriorated credit quality					1,849,066	2,137,897
Total loans					9,895,855	9,511,867
Consumer loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance			26,805
Ending balance	28,067		28,067
Allowance for loan losses
Loans individually evaluated for impairment					1,255	1,330
Loans collectively evaluated for impairment					26,812	25,475
Loans accounted for under ASC 310-30					0	0
Total allowance for loan losses	28,067		28,067		28,067	26,805
Recorded investment (loan balance)
Loans individually evaluated for impairment					24,842	25,835
Loans collectively evaluated for impairment					4,799,479	4,444,951
Loans acquired with deteriorated credit quality					1,141,727	1,287,126
Total loans					5,966,048	5,757,912
Acquired Loan Portfolio [Member]
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	0		420
Provision for loan losses	0		(420)
Charge-offs	0		0
Recoveries	0		0
Ending balance	0		0
Allowance for loan losses
Total allowance for loan losses	0		420		0	420
Acquired Loan Portfolio [Member] | Commercial loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	0		420
Provision for loan losses	0		(420)
Charge-offs	0		0
Recoveries	0		0
Ending balance	0		0
Allowance for loan losses
Total allowance for loan losses	0		0		0	420
Acquired Loan Portfolio [Member] | Consumer loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	0		0
Provision for loan losses	0		0
Charge-offs	0		0
Recoveries	0		0
Ending balance	0		0
Allowance for loan losses
Total allowance for loan losses	0		0		0	0
Originated Loan Portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	110,284	$ 94,762	109,564	$ 91,887
Provision for loan losses	7,502	9,572	9,981	15,828
Charge-offs	(3,624)	(5,726)	(6,829)	(10,550)
Recoveries	1,805	1,407	3,251	2,850
Ending balance	115,967	100,015	115,967	100,015
Allowance for loan losses
Total allowance for loan losses	110,284	94,762	109,564	91,887	115,967	109,564
Originated Loan Portfolio | Commercial loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	84,010	67,744	82,759	66,133
Provision for loan losses	4,848	7,923	6,712	11,323
Charge-offs	(2,013)	(3,890)	(3,447)	(6,484)
Recoveries	1,055	888	1,876	1,693
Ending balance	87,900	72,665	87,900	72,665
Allowance for loan losses
Total allowance for loan losses	84,010	67,744	82,759	66,133	87,900	82,759
Originated Loan Portfolio | Consumer loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	26,274	27,018	26,805	25,754
Provision for loan losses	2,654	1,649	3,269	4,505
Charge-offs	(1,611)	(1,836)	(3,382)	(4,066)
Recoveries	750	519	1,375	1,157
Ending balance	28,067	27,350	28,067	27,350
Allowance for loan losses
Total allowance for loan losses	$ 26,274	$ 27,018	$ 28,067	$ 25,754	$ 28,067	$ 26,805

Other Real Estate Owned and R_3

Other Real Estate Owned and Repossessed Assets - Rollforward Tables (Details) - USD ($) $ in Thousands		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018	Dec. 31, 2017
Repossessed Assets [Line Items]
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]				$ 1,339
Changes in other real estate owned
Balance at the beginning of the period		$ 5,832	$ 8,182
Transfers			(189)
Other additions		5,420	2,448
Net payments received		(214)	(139)
Disposals		(2,372)	(4,642)
Write-downs		(729)	(783)
Balance at the end of the period		7,937	4,877
Changes in repossessed assets
Balance at the beginning of the period		424	625
Transfers			0
Other additions		1,309	2,645
Net payments received		0	0
Disposals		(1,403)	(2,319)
Write-downs		0	0
Balance at the end of the period		330	$ 951
Retained earnings
Repossessed Assets [Line Items]
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]				$ 1,680
ASU 2014-09
Repossessed Assets [Line Items]
Loans to facilitate reclassified to loans		$ 1,100
ASU 2014-09 | Retained earnings
Repossessed Assets [Line Items]
Cumulative effect adjustment of change in accounting policy, net of tax impact				$ 900
[1]	Refer to Note 1 , Basis of Presentation and Significant Accounting Policies, Note 6 , Other Real Estate Owned and Repossessed Assets and Note 20 , Accumulated Other Comprehensive Loss for further details on the changes in accounting policy.

Other Real Estate Owned and R_4

Other Real Estate Owned and Repossessed Assets - Textual (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Other Real Estate [Abstract]
Other real estate owned and repossessed assets acquired in accordance with ASU 2014-04	$ 1.9
Residential mortgage loans in process of foreclosure	$ 3.6	$ 4.5

Other Real Estate Owned and R_5

Other Real Estate Owned and Repossessed Assets - Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income and expenses related to other real estate owned
Net gain (loss) on sale	$ 824	$ 23	$ 1,568	$ 779
Write-downs	(435)	(132)	(729)	(783)
Net operating expenses	(248)	(318)	(555)	(715)
Total	141	(427)	284	(719)
Income and expenses related to repossessed assets
Net gain (loss) on sale	(14)	(60)	(32)	(94)
Write-downs	0	0	0	0
Net operating expenses	(2)	(2)	(5)	(3)
Total	$ (16)	$ (62)	$ (37)	$ (97)

Goodwill (Details)

Goodwill (Details) - USD ($)	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	$ 1,134,568,000	$ 1,134,568,000
Goodwill impairment	$ 0

Loan Servicing Rights - LSRs Ac

Loan Servicing Rights - LSRs Activity (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period	$ 64,701	$ 68,837	$ 71,013	$ 63,841
Additions from loans sold with servicing retained	2,109	2,284	4,242	4,251
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off	(695)	(727)	(1,494)	(1,450)
Changes in estimates of fair value	(5,457)	(30)	(13,103)	3,722
Fair value, end of period	60,658	70,364	60,658	70,364
Principal balance of loans serviced	6,775,213	6,988,846	6,775,213	6,988,846
Commercial Real Estate
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period	559	441	451	427
Additions from loans sold with servicing retained	0	45	138	88
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off	(34)	(29)	(64)	(58)
Changes in estimates of fair value	0	0	0	0
Fair value, end of period	525	457	525	457
Principal balance of loans serviced	43,657	42,490	43,657	42,490
Mortgage
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period	64,142	68,396	70,562	63,414
Additions from loans sold with servicing retained	2,109	2,239	4,104	4,163
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off	(661)	(698)	(1,430)	(1,392)
Changes in estimates of fair value	(5,457)	(30)	(13,103)	3,722
Fair value, end of period	60,133	69,907	60,133	69,907
Principal balance of loans serviced	$ 6,731,556	$ 6,946,356	$ 6,731,556	$ 6,946,356

Loan Servicing Rights - Assumpt

Loan Servicing Rights - Assumptions Used in Determining Fair Value (Details)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)	Dec. 31, 2018USD ($)
Loan servicing rights
Loan servicing fee income	$ 4,200,000	$ 4,400,000	$ 8,400,000	$ 9,000,000
Mortgage
Loan servicing rights
WA cost to service/per year			66		$ 66
WA ancillary income/per year			$ 31		$ 31
WA float range			2.40%
Mortgage | Weighted Average
Loan servicing rights
WA float range					2.50%
Prepayment rate | Mortgage | Minimum
Loan servicing rights
Measurement input	0.060		0.060		0
Prepayment rate | Mortgage | Maximum
Loan servicing rights
Measurement input	0.297		0.297		0.264
Discount rate | Mortgage | Weighted Average
Loan servicing rights
Measurement input	0.101		0.101		0.101

Core Deposit Intangibles - Inta

Core Deposit Intangibles - Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Total intangible assets	$ 25,835	$ 28,556
Core deposit intangible assets
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	56,456	56,456
Accumulated amortization	30,621	27,900
Total intangible assets	$ 25,835	$ 28,556

Core Deposit Intangibles - Text

Core Deposit Intangibles - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets			$ (2,721)	$ (2,864)
Core deposit intangible assets
Finite-Lived Intangible Assets [Line Items]
Weighted average amortization period			6 years 1 month 6 days
Amortization of intangible assets	$ (1,400)	$ (1,400)	$ (2,700)	$ (2,900)

Core Deposit Intangibles - Futu

Core Deposit Intangibles - Future Amortization Expense (Details) - Core deposit intangible assets $ in Thousands	Jun. 30, 2019USD ($)
Finite-Lived Intangible Assets [Line Items]
2019	$ 2,722
2020	4,851
2021	4,471
2022	4,218
2023	3,591
2024 and thereafter	$ 5,982

Derivative Instruments and Ba_3

Derivative Instruments and Balance Sheet Offsetting - Notional Amount and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Derivative instruments
Notional Amount	$ 4,403,278	$ 3,516,418
Gross Derivative Assets	73,068	38,595
Gross Derivative Liabilities	97,179	32,379
Credit valuation adjustments for counterparty credit risk	1,500	901
Derivatives designated as hedging instruments:
Derivative instruments
Notional Amount	1,145,000	820,000
Gross Derivative Assets	606	10,148
Gross Derivative Liabilities	25,060	3,278
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative instruments
Notional Amount	1,145,000	820,000
Gross Derivative Assets	606	10,148
Gross Derivative Liabilities	25,060	3,278
Derivatives not designated as hedging | Total customer-initiated and mortgage banking derivatives
Derivative instruments
Notional Amount	3,258,278	2,696,418
Gross Derivative Assets	72,462	28,447
Gross Derivative Liabilities	72,119	29,101
Derivatives not designated as hedging | Customer-initiated derivatives
Derivative instruments
Notional Amount	2,908,127	2,477,640
Gross Derivative Assets	69,024	26,680
Gross Derivative Liabilities	70,707	27,664
Derivatives not designated as hedging | Forward contracts related to mortgage loans to be delivered for sale
Derivative instruments
Notional Amount	165,772	127,159
Gross Derivative Assets	0	0
Gross Derivative Liabilities	661	719
Derivatives not designated as hedging | Interest rate lock commitments
Derivative instruments
Notional Amount	149,084	54,848
Gross Derivative Assets	2,687	1,049
Gross Derivative Liabilities	0	0
Derivatives not designated as hedging | Power Equity CD
Derivative instruments
Notional Amount	35,295	36,771
Gross Derivative Assets	751	718
Gross Derivative Liabilities	$ 751	$ 718

Derivative Instruments and Ba_4

Derivative Instruments and Balance Sheet Offsetting - Net Gains (Losses) Related to Changes in Fair Value (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative instruments
Total gain (loss) recognized in income	$ 512	$ 229	$ 997	$ 738
Forward contracts related to mortgage loans to be delivered for sale | Net gain on sale of loans and other mortgage banking revenue
Derivative instruments
Total gain (loss) recognized in income	(8)	(21)	58	(391)
Interest rate lock commitments | Net gain on sale of loans and other mortgage banking revenue
Derivative instruments
Total gain (loss) recognized in income	929	211	1,638	763
Customer-initiated derivatives | Other noninterest income
Derivative instruments
Total gain (loss) recognized in income	(409)	39	(699)	366
Power Equity CD | Other noninterest income
Derivative instruments
Total gain (loss) recognized in income	$ 0	$ 0	$ 0	$ 0

Derivative Instruments and Ba_5

Derivative Instruments and Balance Sheet Offsetting - Net Gains (Losses) Recorded in Other Comprehensive Income and the Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative instruments
Unrealized losses on interest rate swaps expected to be reclassified during next twelve months	$ 2,200		$ 2,200
Interest rate swaps | Derivatives designated as hedging instruments:
Derivative instruments
Amount of gain (loss) recognized in other comprehensive income	(21,229)	$ 4,102	(28,781)	$ 12,065
Amount of gain (loss) reclassified from other comprehensive income to interest income or expense	$ 1,256	$ 589	$ 2,544	$ 347

Derivative Instruments and Ba_6

Derivative Instruments and Balance Sheet Offsetting - Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Offsetting derivative assets
Gross amounts recognized	$ 73,068	$ 38,595
Offsetting derivative liabilities
Gross amounts recognized	97,179	32,379
Interest rate swaps and customer-initiated derivatives
Offsetting derivative assets
Gross amounts recognized	69,553	36,791
Gross amounts offset in the statements of financial condition	0	0
Net amounts presented in the statements of financial position	69,553	36,791
Gross amounts not offset in the statements of financial position
Financial instruments	0	0
Collateral (received)/posted	0	(16,120)
Net Amount	69,553	20,671
Offsetting derivative liabilities
Gross amounts recognized	95,492	30,822
Gross amounts offset in the statements of financial condition	0	0
Net amounts presented in the statements of financial position	95,492	30,822
Gross amounts not offset in the statements of financial position
Financial instruments	0	0
Collateral (received)/posted	37,291	430
Net Amount	$ 58,201	$ 30,392

Investments in Qualified Affo_2

Investments in Qualified Affordable Housing Projects, Federal Historic Projects and New Market Tax Credits (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Variable Interest Entity [Line Items]
Expense related to qualified affordable housing projects	$ 1,600	$ 1,100	$ 3,300	$ 2,100
Remaining investment in qualified affordable housing projects	85,800		85,800		$ 84,900
Equity method investments	32,100		32,100		13,300
Remaining unfunded equity contributions	$ 73,400		73,400		$ 72,000
Investment tax credit		1,900	260	3,400
Impairment on tax credit projects		1,700	271	3,400
Other Noninterest Expense [Member]
Variable Interest Entity [Line Items]
Impairment on tax credit projects		$ 1,400	$ 214	$ 2,600

Leases - Narrative (Details)

Leases - Narrative (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Lessee, Lease, Description [Line Items]
Real property leases not yet commenced	$ 247,400	$ 247,400
Operating lease liability incurred for right of use asset	877	6,700
Operating lease payments	2,000	4,000
Right of use assets	40,500	40,500
Operating lease liability	41,403	41,403
2019			$ 7,300
2020			6,200
2021			5,100
2022			4,800
2023			4,400
2024			12,100
Premises and equipment	123,708	123,708	$ 123,442
Underlying assets under operating leases	$ 15,100	$ 15,100
Minimum
Lessee, Lease, Description [Line Items]
Lease term	1 year	1 year
Renewal term	3 years	3 years
Maximum
Lessee, Lease, Description [Line Items]
Lease term	15 years	15 years
Renewal term	5 years	5 years
Affiliated Entity
Lessee, Lease, Description [Line Items]
Lease term	22 years 6 months	22 years 6 months
Real property leases not yet commenced	$ 231,600	$ 231,600
Ownership interest	50.00%	50.00%

Leases - Supplemental Lease Inf

Leases - Supplemental Lease Information (Details)	Jun. 30, 2019
Leases [Abstract]
Weighted-average remaining lease terms (in years)	7 years 10 months 6 days
Weighted-average discount rate	3.10%

Leases - Components of Lease Ex

Leases - Components of Lease Expense (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Operating lease cost	$ 2,050	$ 3,964
Variable lease cost	247	454
Sublease income	(56)	(111)
Total lease cost	$ 2,241	$ 4,307

Leases - Lease Maturities (Deta

Leases - Lease Maturities (Details) $ in Thousands	Jun. 30, 2019USD ($)
Operating Leases
Remainder of 2019	$ 4,081
2020	7,490
2021	7,083
2022	6,149
2023	5,017
Thereafter	17,041
Total	46,861
Less: Present value discount	5,458
Lease liability	$ 41,403

Leases - Components of Lease In

Leases - Components of Lease Income (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Leases [Abstract]
Lease income - operating leases	$ 169	$ 363
Total lease income	$ 169	$ 363

Commitments, Contingencies an_3

Commitments, Contingencies and Guarantees - Commitments (Details) - USD ($)	Jun. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Potential losses from standby letters of credit	$ 329,000	$ 0
Undisbursed loan commitments	537,600,000	493,300,000
Probable credit losses	1,900,000	1,700,000
Financial and Performance Standby Letters of Credit
Loss Contingencies [Line Items]
Letters of credit outstanding	123,700,000	119,000,000
Commitments to Extend Credit
Loss Contingencies [Line Items]
Loan commitments under financial guarantee	3,820,000,000	3,550,000,000
Performance Guarantee
Loss Contingencies [Line Items]
Recourse liability	100,000	100,000
SBA Guaranteed Notes | Performance Guarantee
Loss Contingencies [Line Items]
Recourse liability	$ 891,000	$ 1,200,000

Commitments, Contingencies an_4

Commitments, Contingencies and Guarantees - Contingencies and Guarantees (Details) - Performance Guarantee - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Loss Contingencies [Line Items]
Recorded liability	$ 12,800	$ 11,600
Maximum potential amount of undiscounted future payments	12,600	11,400
Recourse liability	100	100
SBA Guaranteed Notes
Loss Contingencies [Line Items]
Maximum potential amount of undiscounted future payments	17,900	19,100
Recourse liability	$ 891	$ 1,200

Commitments, Contingencies an_5

Commitments, Contingencies and Guarantees - Warranties (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Dec. 31, 2018
Changes in the activity related to liability recorded in connection with representations and warranties
Reserve balance at beginning of period	$ 3,983	$ 5,105	$ 4,084	$ 5,349
Reserve reduction	(807)	(243)	(908)	(487)
Charge-offs	0	(2)	0	(2)
Ending reserve balance	3,176	4,860	3,176	4,860
Reserve balance
Liability for specific claims					$ 454	$ 398
General allowance					2,722	3,686
Total reserve balance	$ 3,983	$ 5,105	$ 4,084	$ 5,349	$ 3,176	$ 4,084

Borrowings and Other Short-Te_3

Borrowings and Other Short-Term Liabilities - Short/Long-term and Other Short-term Borrowings (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Short-term borrowings:
Amount	$ 2,615,000	$ 2,035,000
Weighted Average Rate	2.44%	2.47%
Long-term borrowings:
Amount	$ 426,069	$ 426,002
Weighted Average Rate	2.11%	2.11%
Total borrowings	$ 3,041,069	$ 2,461,002
Total short-term and long-term borrowings, Weighted Average Rate	2.39%	2.41%
FHLB advances: 2.29% - 2.60% fixed-rate notes | Minimum
Long-term borrowings:
Stated interest rate	2.29%
FHLB advances: 2.29% - 2.60% fixed-rate notes | Maximum
Long-term borrowings:
Stated interest rate	2.60%
AFX short-term borrowings
Short-term borrowings:
Amount	$ 35,000	$ 0
Weighted Average Rate	2.41%	0.00%
FHLB Advances | FHLB advances: 1.00% - 2.72% fixed-rate notes due 2019 to 2025
Long-term borrowings:
Amount	$ 410,073	$ 410,102
Weighted Average Rate	2.00%	2.00%
Advances payable from Federal Home Loan Banks	$ 410,000	$ 410,000
Purchase accounting premiums	$ 73	102
FHLB Advances | FHLB advances: 1.00% - 2.72% fixed-rate notes due 2019 to 2025 | Minimum
Long-term borrowings:
Stated interest rate	1.00%
FHLB Advances | FHLB advances: 1.00% - 2.72% fixed-rate notes due 2019 to 2025 | Maximum
Long-term borrowings:
Stated interest rate	2.72%
Subordinated debt obligations | Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035
Long-term borrowings:
Amount	$ 11,648	$ 11,572
Weighted Average Rate	4.71%	4.85%
Advances payable	$ 15,000	$ 15,000
Purchase accounting discounts	$ 3,400	3,400
Subordinated debt obligations | Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035 | Minimum
Long-term borrowings:
Spread on variable rate	1.45%
Subordinated debt obligations | Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035 | Maximum
Long-term borrowings:
Spread on variable rate	2.85%
Subordinated debt obligations | Subordinated debt obligations: floating-rate based on three-month LIBOR plus 3.25% due in 2032
Long-term borrowings:
Amount	$ 4,348	$ 4,328
Weighted Average Rate	5.84%	5.65%
Spread on variable rate	3.25%
Advances payable	$ 5,000	$ 5,000
Purchase accounting discounts	652	672
Collateralized customer deposits
Short-term borrowings:
Amount	$ 291,671	$ 382,687
Weighted Average Rate	0.70%	0.75%
FHLB Advances | FHLB advances: 2.29% - 2.60% fixed-rate notes
Short-term borrowings:
Amount	$ 2,580,000	$ 2,035,000
Weighted Average Rate	2.44%	2.47%

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Noninterest income	$ 38,164	$ 38,018	$ 63,021	$ 78,572
Noninterest expense	111,003	104,561	220,018	206,171
Noninterest income from contracts with customers within the scope of ASC 606
Disaggregation of Revenue [Line Items]
Noninterest income	5,551	7,119	11,065	14,764
Service charges and fees on deposit accounts
Disaggregation of Revenue [Line Items]
Noninterest income	2,986	4,462	5,983	8,925
Wealth management revenue
Disaggregation of Revenue [Line Items]
Noninterest income	1,321	1,268	2,621	2,052
Other charges and fees for customer services
Disaggregation of Revenue [Line Items]
Noninterest income	1,244	1,389	2,461	3,787
Noninterest income within the scope of other GAAP topics
Disaggregation of Revenue [Line Items]
Noninterest income	32,613	30,899	51,956	63,808
Other
Disaggregation of Revenue [Line Items]
Noninterest expense	$ 810	$ 38	$ 1,536	$ 684

Borrowings and Other Short-Te_4

Borrowings and Other Short-Term Liabilities - Textual (Details) $ in Millions	Jun. 30, 2019USD ($)
Debt Disclosure [Abstract]
FHLB advances	$ 7,700
Additional borrowing available through FHLB	$ 25

Share-Based Compensation - Text

Share-Based Compensation - Textual (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)$ / sharesshares	Jun. 30, 2018USD ($)	May 07, 2019shares	Dec. 31, 2018USD ($)
Share-based Compensation Plans (Textual)
Share-based compensation expense	$ 2,800	$ 2,400	$ 5,100	$ 4,100
Excess tax benefit from share-based compensation transactions	$ (16)	$ 399	306	1,800
Cash received from option exercises			$ 338	$ 2,200
Stock Incentive Plan of 2019
Share-based Compensation Plans (Textual)
Number of shares authorized under stock incentive plan (in shares) | shares					2,400,000
Common stock available for future grants under share-based compensation plans (in shares) | shares	2,388,937		2,388,937
Stock Incentive Plans After 2012
Share-based Compensation Plans (Textual)
Vesting period			5 years
Stock options
Share-based Compensation Plans (Textual)
Stock option award vesting period			10 years
Outstanding in-the-money stock options, intrinsic value	$ 19,800		$ 19,800			$ 26,600
Restricted stock units
Share-based Compensation Plans (Textual)
Corporation granted options to purchase restricted stock performance units (in shares) | shares			379,260
Stock issued from exercises (in shares) | shares			123,686
Unrecognized compensation expense	27,600		$ 27,600
Unrecognized compensation expense, period for recognition			3 years 6 months
Restricted stock units | Minimum
Share-based Compensation Plans (Textual)
Restricted stock performance units eligible to vest as a multiple of number of units granted			0.5
Restricted stock units | Maximum
Share-based Compensation Plans (Textual)
Restricted stock performance units eligible to vest as a multiple of number of units granted			1.5
Equity Option
Share-based Compensation Plans (Textual)
Weighted-average remaining contractual terms for outstanding stock options			5 years 2 months 12 days
Weighted-average remaining contractual terms for exercisable stock options			4 years 9 months 18 days
Outstanding in-the-money stock options, intrinsic value	7,500		$ 7,500
Exercisable in-the-money stock options, intrinsic value	$ 6,800		$ 6,800
Closing price of common stock (dollars per share) | $ / shares	$ 41.11		$ 41.11
Unrecognized compensation expense	$ 901		$ 901
Unrecognized compensation expense, period for recognition			2 years 1 month 6 days

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Activity (Details) - Stock Options	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Non-Vested Stock Options Outstanding, Number of Options
Vested (in shares) | shares	0
Non-Vested Stock Options Outstanding, Weighted- Average Grant Date Fair Value Per Share
Beginning balance (dollars per share)	$ 7.16
Vested (dollars per share)	6.98
Forfeited/expired (dollars per share)	6.82
Ending balance (dollars per share)	$ 7.33
Stock Options Outstanding, Number of Options
Beginning balance (in shares) | shares	777,443
Exercised (in shares) | shares	(97,284)
Ending balance (in shares) | shares	648,285
Weighted- Average Exercise Price Per Share
Beginning balance, Weighted Average Exercise Price (dollars per share)	$ 31.42
Exercised, Weighted Average Exercise Price (dollars per share)	29.69
Forfeited/expired, Weighted Average Exercise Price (dollars per share)	36.40
Ending balance, Weighted Average Exercise Price (dollars per share)	$ 31.43
Exercisable/vested, Number of Options (in shares) | shares	520,297
Exercisable/vested, Weighted Average Exercise Price (dollars per share)	$ 29.48
Vested, Weighted Average Exercise Price (dollars per share)	$ 0
Forfeited/expired (in shares) | shares	31,874
Non Vested
Non-Vested Stock Options Outstanding, Number of Options
Beginning balance (in shares) | shares	221,658
Vested (in shares) | shares	(65,104)
Forfeited/expired (in shares) | shares	(28,566)
Ending balance (in shares) | shares	127,988
Stock Options Outstanding, Number of Options
Exercised (in shares) | shares	0
Weighted- Average Exercise Price Per Share
Beginning balance, Weighted Average Exercise Price (dollars per share)	$ 38.37
Exercised, Weighted Average Exercise Price (dollars per share)	0
Forfeited/expired, Weighted Average Exercise Price (dollars per share)	36.40
Vested, Weighted Average Exercise Price (dollars per share)	37.24
Ending balance, Weighted Average Exercise Price (dollars per share)	$ 39.38

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Stock Unit and Award Activity (Details)	6 Months Ended
	Jun. 30, 2019$ / sharesshares
Restricted Stock Units
Number of Units/Awards
Beginning balance (in shares) | shares	576,490
Granted (in shares) | shares	379,260
Converted into shares of common stock (in shares) | shares	(123,686)
Forfeited/expired (in shares) | shares	(21,406)
Ending balance (in shares) | shares	810,658
Weighted-average grant-date fair value
Beginning balance (dollars per share) | $ / shares	$ 49.35
Granted (dollars per share) | $ / shares	44.95
Converted into shares of common stock (dollars per share) | $ / shares	38.83
Forfeited/expired (dollars per share) | $ / shares	50.03
Ending balance (dollars per share) | $ / shares	$ 48.88
Restricted Stock Awards
Number of Units/Awards
Beginning balance (in shares) | shares	40,852
Vested (in shares) | shares	(40,852)
Ending balance (in shares) | shares	0
Weighted-average grant-date fair value
Beginning balance (dollars per share) | $ / shares	$ 46.23
Vested (dollars per share) | $ / shares	46.23
Ending balance (dollars per share) | $ / shares	$ 0

Retirement Plans - Net Periodic

Retirement Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Pension Plans
Components of net periodic benefit cost (income) for the Corporation's qualified and nonqualified pension plans and nonqualified postretirement benefits plan
Interest cost	$ 1,172	$ 1,092	$ 2,345	$ 2,184
Expected return on plan assets	(2,190)	(2,220)	(4,381)	(4,439)
Amortization of unrecognized net (gain) loss	141	178	281	355
Net periodic benefit cost (income)	(877)	(950)	(1,755)	(1,900)
Postretirement Benefit Plan
Components of net periodic benefit cost (income) for the Corporation's qualified and nonqualified pension plans and nonqualified postretirement benefits plan
Service cost	0	1	1	1
Interest cost	21	20	43	41
Amortization of unrecognized net (gain) loss	(45)	(36)	(90)	(71)
Net periodic benefit cost (income)	$ (24)	$ (15)	$ (46)	$ (29)

Retirement Plans - Textual (Det

Retirement Plans - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Defined Benefit Plan Disclosure [Line Items]
Fair value of Pension Plan assets in excess of recorded liability	$ 19,000		$ 19,000
Maximum percent of participants' base compensation matched			6.00%
Employer total contribution amount	2,400	$ 2,000	$ 4,800	$ 4,800
Defined Benefit Pension Plans | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for pension plan expense			4.32%
Defined Benefit Pension Plans | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Liability related to SERP plan	$ 333		$ 333

Regulatory Capital and Reserv_3

Regulatory Capital and Reserve Requirements (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Leverage Ratio
Cash dividends declared per common share (dollars per share)	$ 0.34	$ 0.28	$ 0.68	$ 0.56
Chemical Bank
Regulatory Capital
Risk weighted assets	$ 16,990,000		$ 16,990,000		$ 16,070,000
Total Capital to Risk-Weighted Assets
Actual Amount	$ 1,928,735		$ 1,928,735		$ 1,825,742
Actual Ratio	11.30%		11.30%		11.40%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 1,784,388		$ 1,784,388		$ 1,586,719
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	10.50%		10.50%		9.90%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,699,417		$ 1,699,417		$ 1,606,804
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	10.00%		10.00%		10.00%
Tier 1 Capital to Risk-Weighted Assets
Actual Amount	$ 1,806,734		$ 1,806,734		$ 1,708,724
Actual Ratio	10.60%		10.60%		10.60%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 1,444,504		$ 1,444,504		$ 1,265,358
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	8.50%		8.50%		7.90%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,359,534		$ 1,359,534		$ 1,285,444
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	8.00%		8.00%		8.00%
Common Equity Tier 1 Capital to Risk-Weighted Assets
Actual Amount	$ 1,806,734		$ 1,806,734		$ 1,708,724
Actual Ratio	10.60%		10.60%		10.60%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 1,189,592		$ 1,189,592		$ 1,024,338
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	7.00%		7.00%		6.40%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,104,621		$ 1,104,621		$ 1,044,423
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	6.50%		6.50%		6.50%
Leverage Ratio
Actual Amount	$ 1,806,734		$ 1,806,734		$ 1,708,724
Actual Ratio	8.70%		8.70%		8.60%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 832,372		$ 832,372		$ 792,184
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	4.00%		4.00%		4.00%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount	$ 1,040,465		$ 1,040,465		$ 990,230
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio	5.00%		5.00%		5.00%
Corporation
Regulatory Capital
Risk weighted assets	$ 17,020,000		$ 17,020,000		$ 16,100,000
Total Capital to Risk-Weighted Assets
Actual Amount	$ 1,951,444		$ 1,951,444		$ 1,855,922
Actual Ratio	11.50%		11.50%		11.50%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 1,787,527		$ 1,787,527		$ 1,590,323
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	10.50%		10.50%		9.90%
Tier 1 Capital to Risk-Weighted Assets
Actual Amount	$ 1,813,446		$ 1,813,446		$ 1,723,004
Actual Ratio	10.70%		10.70%		10.70%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 1,447,046		$ 1,447,046		$ 1,268,232
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	8.50%		8.50%		7.90%
Common Equity Tier 1 Capital to Risk-Weighted Assets
Actual Amount	$ 1,813,446		$ 1,813,446		$ 1,723,004
Actual Ratio	10.70%		10.70%		10.70%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 1,191,685		$ 1,191,685		$ 1,026,664
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	7.00%		7.00%		6.40%
Leverage Ratio
Actual Amount	$ 1,813,446		$ 1,813,446		$ 1,723,004
Actual Ratio	8.70%		8.70%		8.70%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount	$ 833,418		$ 833,418		$ 793,669
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio	4.00%		4.00%		4.00%

Earnings Per Common Share (Deta

Earnings Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net income	$ 69,594	$ 68,988	$ 132,536	$ 140,584
Net income allocated to participating securities	0	40	24	105
Net income allocated to common shareholders	$ 69,594	$ 68,948	$ 132,512	$ 140,479
Weighted average common shares - issued (in shares)	71,554,000	71,371,000	71,526,000	71,334,000
Average unvested restricted share awards (in shares)	0	(42,000)	(12,000)	(54,000)
Weighted average common shares outstanding - basic (in shares)	71,554,000	71,329,000	71,514,000	71,280,000
Effect of dilutive securities
Weighted average common stock equivalents (in shares)	718,000	697,000	693,000	686,000
Weighted average common shares outstanding - diluted (in shares)	72,272,000	72,026,000	72,207,000	71,966,000
EPS available to common shareholders
Basic earnings per common share (dollars per share)	$ 0.97	$ 0.97	$ 1.85	$ 1.97
Diluted earnings per common share (dollars per share)	0.96	0.96	1.84	1.95
Average stock valuation (dollars per share)	$ 41.46	$ 56.46	$ 42.33	$ 56.35
Stock Option
Schedule Of Earnings Per Share By Common Class [Line Items]
Average number of exercisable employee stock option awards that were not included in the computation of diluted earnings per common share (in shares)	41,695	59,303	46,940	65,114

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Changes in AOCI (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2017
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance		$ 2,897,509	$ 2,704,703	$ 2,836,260	$ 2,668,749
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]					$ 1,339
Other comprehensive income (loss) before reclassifications		12,308	(5,942)	35,923	(21,460)
Amounts reclassified from accumulated other comprehensive income (loss)		(4,202)	(355)	(5,214)	(52)
Other comprehensive income (loss), net of tax		8,106	(6,297)	30,709	(21,512)
Ending balance		2,953,535	2,750,999	2,953,535	2,750,999
Unrealized gains (losses) on securities carried at fair value, net of tax
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance		(8,260)	(32,501)	(37,772)	(10,348)
Cumulative effect adjustment of change in accounting policy, net of tax impact						(344)
Beginning balance, adjusted						(10,692)
Other comprehensive income (loss) before reclassifications		29,079	(9,182)	58,660	(30,991)
Amounts reclassified from accumulated other comprehensive income (loss)		(3,286)	(2)	(3,355)	(2)
Other comprehensive income (loss), net of tax		25,793	(9,184)	55,305	(30,993)
Ending balance		17,533	(41,685)	17,533	(41,685)
Defined Benefit Pension Plan, net of tax
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance		(28,691)	(19,696)	(28,766)	(19,808)
Cumulative effect adjustment of change in accounting policy, net of tax impact						0
Beginning balance, adjusted						(19,808)
Other comprehensive income (loss) before reclassifications		0	0	0	0
Amounts reclassified from accumulated other comprehensive income (loss)		76	112	151	224
Other comprehensive income (loss), net of tax		76	112	151	224
Ending balance		(28,615)	(19,584)	(28,615)	(19,584)
Unrealized gains (losses) on cash flow hedges, net of tax
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance		(1,556)	11,143	5,428	4,658
Cumulative effect adjustment of change in accounting policy, net of tax impact						3
Beginning balance, adjusted						4,661
Other comprehensive income (loss) before reclassifications		(16,771)	3,240	(22,737)	9,531
Amounts reclassified from accumulated other comprehensive income (loss)		(992)	(465)	(2,010)	(274)
Other comprehensive income (loss), net of tax		(17,763)	2,775	(24,747)	9,257
Ending balance		(19,319)	13,918	(19,319)	13,918
Total
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance		(38,507)	(41,054)	(61,110)	(25,498)
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]					(341)
Beginning balance, adjusted						$ (25,839)
Ending balance		$ (30,401)	$ (47,351)	$ (30,401)	$ (47,351)
[1]	Refer to Note 1 , Basis of Presentation and Significant Accounting Policies, Note 6 , Other Real Estate Owned and Repossessed Assets and Note 20 , Accumulated Other Comprehensive Loss for further details on the changes in accounting policy.

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net gain on sale of investment securities	$ 4,160	$ 3	$ 4,247	$ 3
Income tax expense	(15,226)	(12,434)	(28,891)	(25,389)
Net income	69,594	68,988	132,536	140,584
Interest on short-term borrowings (interest expense)	165,161	157,537	327,985	309,400
Gains and losses on investment securities carried at fair value | Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net gain on sale of investment securities	4,160	3	4,247	3
Income tax expense	(874)	(1)	(892)	(1)
Net income	3,286	2	3,355	2
Amortization of defined benefit pension plan items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries, wages and employee benefits (operating expenses)	96	142	191	284
Income tax expense	(20)	(30)	(40)	(60)
Net Loss	76	112	151	224
Gains and losses on cash flow hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income tax expense	264	124	534	73
Gains and losses on cash flow hedges | Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Net income	(992)	(465)	(2,010)	(274)
Interest on short-term borrowings (interest expense)	$ (1,256)	$ (589)	$ (2,544)	$ (347)