TCF Financial 10-Q 9 Aug 17 2017 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2017	Aug. 07, 2017
Document and Entity Information [Abstract]
Entity Registrant Name	CHEMICAL FINANCIAL CORP
Entity Central Index Key	19,612
Document Type	10-Q
Document Period End Date	Jun. 30, 2017
Amendment Flag	false
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		71,144,387

Consolidated Statements of Fina

Consolidated Statements of Financial Position - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Cash and cash equivalents:
Cash and cash due from banks	$ 230,219	$ 237,758
Interest-bearing deposits with the Federal Reserve Bank and other banks	389,022	236,644
Total cash and cash equivalents	619,241	474,402
Investment securities:
Available-for-sale, at fair value	1,767,478	1,234,964
Held-to-maturity, at amortized cost (fair value of $640,043 and $608,531, respectively)	645,605	623,427
Total investment securities	2,413,083	1,858,391
Loans held-for-sale, at fair value	65,371	81,830
Loans	13,667,372	12,990,779
Allowance for loan losses	(83,797)	(78,268)
Net loans	13,583,575	12,912,511
Premises and equipment	146,460	145,012
Loan servicing rights ($64,522 and $48,085 measured at fair value, respectively)	64,522	58,315
Goodwill	1,133,534	1,133,534
Other intangible assets	37,322	40,211
Interest receivable and other assets	718,297	650,973
Total assets	18,781,405	17,355,179
Deposits:
Noninterest-bearing	3,626,592	3,341,520
Interest-bearing	9,577,775	9,531,602
Total deposits	13,204,367	12,873,122
Interest payable and other liabilities	141,702	134,637
Securities sold under agreements to repurchase with customers	310,042	343,047
Short-term borrowings	2,050,000	825,000
Long-term borrowings	435,852	597,847
Total liabilities	16,141,963	14,773,653
Shareholders’ equity
Preferred stock, no par value: Authorized – 2,000,000 shares at 6/30/2017 and 12/31/2016, none issued	0	0
Common stock, $1.00 par value per share: Authorized — 135,000,000 shares at 6/30/2017 and 100,000,000 shares at 12/31/2016, Issued and outstanding — XX,XXX,XXX shares at 6/30/2017 and 70,599,133 shares at 12/31/2016	71,131	70,599
Additional paid-in capital	2,197,501	2,210,762
Retained earnings	404,939	340,201
Accumulated other comprehensive loss	(34,129)	(40,036)
Total shareholders’ equity	2,639,442	2,581,526
Total liabilities and shareholders’ equity	$ 18,781,405	$ 17,355,179

Consolidated Statements of Fin3

Consolidated Statements of Financial Position (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Statement of Financial Position [Abstract]
Held-to-maturity, fair value	$ 640,043	$ 608,531
Loan servicing rights, fair value	$ 64,522	$ 48,085
Preferred stock, no par value (dollars per share)
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	100,000,000
Common stock, shares issued (in shares)	71,131,042	70,599,133
Common stock, shares outstanding (in shares)	71,131,042	70,599,133

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Interest income
Interest and fees on loans	$ 141,314	$ 77,578	$ 273,799	$ 151,979
Interest on investment securities:
Taxable	7,125	1,798	11,881	3,727
Tax-exempt	4,426	2,640	8,661	5,305
Dividends on nonmarketable equity securities	1,246	777	1,867	1,033
Interest on deposits with the Federal Reserve Bank, other banks and Federal funds sold	1,022	144	1,821	357
Total interest income	155,133	82,937	298,029	162,401
Interest expense
Interest on deposits	10,582	4,260	19,498	8,319
Interest on short-term borrowings	4,659	226	6,317	326
Interest on long-term borrowings	1,944	956	4,169	1,931
Total interest expense	17,185	5,442	29,984	10,576
Net interest income	137,948	77,495	268,045	151,825
Provision for loan losses	6,229	3,000	10,279	4,500
Net interest income after provision for loan losses	131,719	74,495	257,766	147,325
Noninterest income
Service charges and fees on deposit accounts	8,777	6,337	16,781	12,057
Wealth management revenue	6,958	5,782	12,785	10,983
Other charges and fees for customer services	9,734	6,463	18,625	12,855
Net gain on sale of loans and other mortgage banking revenue	9,879	1,595	19,039	3,000
Gain on sale of investment securities	77	18	167	37
Other	6,143	702	12,181	1,384
Total noninterest income	41,568	20,897	79,578	40,316
Operating expenses
Salaries, wages and employee benefits	52,601	33,127	112,849	67,017
Occupancy	8,745	5,514	16,137	10,419
Equipment and software	8,149	4,875	16,666	9,279
Merger and acquisition-related transaction expenses	465	3,054	4,632	5,648
Other	28,277	12,515	52,149	25,609
Total operating expenses	98,237	59,085	202,433	117,972
Income before income taxes	75,050	36,307	134,911	69,669
Income tax expense	23,036	10,532	35,293	20,289
Net income	$ 52,014	$ 25,775	$ 99,618	$ 49,380
Earnings per common share:
Basic (dollars per share)	$ 0.73	$ 0.67	$ 1.41	$ 1.29
Diluted (dollars per share)	0.73	0.67	1.39	1.28
Cash dividends declared per common share (dollars per share)	$ 0.27	$ 0.26	$ 0.54	$ 0.52

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Comprehensive Income [Abstract]
Net income	$ 52,014	$ 25,775	$ 99,618	$ 49,380
Other comprehensive income, net of tax:
Unrealized holding gains on securities available-for-sale arising during the period	5,528	2,121	8,267	6,320
Reclassification adjustment for gains on realized income	(77)	(18)	(167)	(37)
Tax effect	(1,908)	(736)	(2,835)	(2,199)
Net unrealized gains on securities available-for-sale, net of tax	3,543	1,367	5,265	4,084
Unrealized losses on interest rate swaps designated as cash flow hedges	(466)	0	(466)	0
Reclassification adjustment for losses included in net income	409	0	409	0
Net unrealized losses on interest rate swaps designated as cash flow hedges, net of tax	(57)	0	(57)	0
Adjustment for pension and other postretirement benefits	539	(577)	1,076	(1,154)
Tax effect	(189)	202	(377)	404
Net adjustment for pension and other postretirement benefits	350	(375)	699	(750)
Other comprehensive income, net of tax	3,836	992	5,907	3,334
Total comprehensive income, net of tax	$ 55,850	$ 26,767	$ 105,525	$ 52,714

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands		Total	Directors' stock plans	Stock options	Restricted stock units	Restricted stock awards	Common stock	Common stockDirectors' stock plans	Common stockStock options	Common stockRestricted stock units	Common stockRestricted stock awards	Additional paid-in capital	Additional paid-in capitalDirectors' stock plans	Additional paid-in capitalStock options	Additional paid-in capitalRestricted stock units	Additional paid-in capitalRestricted stock awards	Retained earnings	Accumulated other comprehensive income (loss)
Beginning balance at Dec. 31, 2015		$ 1,015,974					$ 38,168					$ 725,280					$ 281,558	$ (29,032)
Changes in Stockholders' Equity
Comprehensive income		52,714															49,380	3,334
Cash dividends declared and paid, $0.54 and $0.52 per share at June 30, 2017 and June 30, 2016, respectively		(19,942)															(19,942)
Shares issued under share-based compensation			$ 125	$ 400				$ 5	$ 48				$ 120	$ 352
Net shares issued - restricted stock units/awards					$ (752)					$ 45					$ (797)
Share-based compensation expense		1,780					1					1,779
Ending balance at Jun. 30, 2016		1,050,299					38,267					726,734					310,996	(25,698)
Beginning balance at Mar. 31, 2016																		(26,690)
Changes in Stockholders' Equity
Comprehensive income		26,767
Ending balance at Jun. 30, 2016		1,050,299					38,267					726,734					310,996	(25,698)
Changes in Stockholders' Equity
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]	3,659															3,659
Beginning balance at Dec. 31, 2016		2,581,526					70,599					2,210,762					340,201	(40,036)
Changes in Stockholders' Equity
Comprehensive income		105,525															99,618	5,907
Cash dividends declared and paid, $0.54 and $0.52 per share at June 30, 2017 and June 30, 2016, respectively		(38,539)															(38,539)
Shares issued under share-based compensation				$ (17,078)					$ 523					$ (17,601)
Net shares issued - restricted stock units/awards					$ (1,296)	$ (1,283)				$ 35	$ (27)				$ (1,331)	$ (1,256)
Share-based compensation expense		6,928					1					6,927
Ending balance at Jun. 30, 2017		2,639,442					71,131					2,197,501					404,939	(34,129)
Beginning balance at Mar. 31, 2017																		(37,965)
Changes in Stockholders' Equity
Comprehensive income		55,850
Ending balance at Jun. 30, 2017		$ 2,639,442					$ 71,131					$ 2,197,501					$ 404,939	$ (34,129)
[1]	Refer to Note 1, Basis of Presentation and Significant Accounting Policies and Note 8, Loan Servicing Rights, for further details on the changes in accounting policy.

Consolidated Statements of Cha7

Consolidated Statements of Changes in Shareholders' Equity (Parenthetical) - $ / shares	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Statement of Stockholders' Equity [Abstract]
Dividend declared (dollars per share)	$ 0.27	$ 0.26	$ 0.54	$ 0.52

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Cash flows from operating activities
Net income	$ 99,618	$ 49,380
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	10,279	4,500
Gain on sales of loans	(20,025)	(3,431)
Proceeds from sales of loans	391,475	119,845
Loans originated for sale	(353,034)	(120,077)
Net gains on sale of investment securities	(167)	(37)
Net gains from sales/writedowns of other real estate and repossessed assets	(871)	(2,512)
Depreciation of premises and equipment	8,989	5,562
Amortization of intangible assets	3,039	4,339
Additions to loan servicing rights	(4,137)	(917)
Valuation change in loan servicing rights	3,591	412
Net amortization of premiums and discounts on investment securities	8,880	2,891
Share-based compensation expense	6,928	1,780
Deferred income tax expense	30,986	0
Net increase in interest receivable and other assets	(105,853)	(12,287)
Net increase (decrease) in interest payable and other liabilities	7,865	(4,139)
Net cash provided by operating activities	87,563	45,309
Investment securities – available-for-sale:
Proceeds from maturities, calls and principal reductions	143,335	94,528
Proceeds from sales and redemptions	10,050	5,000
Purchases	(685,689)	0
Investment securities – held-to-maturity:
Proceeds from maturities, calls and principal reductions	63,339	57,518
Purchases	(86,340)	(101,295)
Net increase in loans	(689,632)	(385,814)
Proceeds from sales of other real estate and repossessed assets	9,606	6,528
Purchases of premises and equipment, net of disposals	(10,437)	(3,897)
Net cash used in investing activities	(1,245,768)	(327,432)
Cash flows from financing activities
Net increase in interest- and noninterest-bearing demand deposits and savings accounts	354,480	95,263
Net decrease in time deposits	(23,235)	(87,384)
Net increase in securities sold under agreements to repurchase with customers and other short-term borrowings	1,191,995	159,014
Proceeds from issuance of long-term borrowings	0	150,000
Repayment of long-term borrowings	(162,000)	(20,558)
Cash dividends paid	(38,539)	(19,942)
Proceeds from directors’ stock plans and exercise of stock options, net of shares withheld	1,639	653
Cash paid for payroll taxes upon conversion of share-based awards	(21,296)	(752)
Net cash provided by financing activities	1,303,044	276,294
Net increase (decrease) in cash and cash equivalents	144,839	(5,829)
Cash and cash equivalents at beginning of period	474,402	238,789
Cash and cash equivalents at end of period	619,241	232,960
Supplemental disclosures of cash flow information:
Interest paid	30,287	10,764
Net income tax (refunds) payments	(4,689)	11,700
Loans transferred to other real estate and repossessed assets	6,332	3,370
Net transfer of loans held-for-sale to loans held- for-investment	(1,957)	0
Closed branch offices transferred to other assets	$ 0	$ 1,863

Basis of Presentation and Signi

Basis of Presentation and Significant Accounting Policies	6 Months Ended
	Jun. 30, 2017
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 Midland, Michigan, that operates through one commercial bank, Chemical Bank. Chemical Bank operates within Michigan, Ohio and Indiana as a Michigan state-chartered commercial bank. Chemical Bank operates through an internal organizational structure of seven regional banking units and offers a full range of traditional banking and fiduciary products and services to the residents and business customers in the bank’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 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, 2016. 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. Operating results for the six months ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 . 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, fair value amounts related to business combinations, income taxes, goodwill impairment and those assets and liabilities that require fair value measurement. 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 with the current presentation. The reclassification had no effect on net income or shareholders’ equity as previously reported. Recently Adopted Accounting Principles Loan Servicing Rights Effective January 1, 2017, the Corporation elected to account for all loan servicing rights ("LSRs") previously accounted for under the lower of cost or fair value method under the fair value method. The guidance in Accounting Standards Codification Subtopic 860-50, "Transfers and Servicing-Servicing Assets and Liabilities" provides that an entity may make an irrevocable decision to subsequently measure a class of servicing assets and servicing liabilities at fair value at the beginning of any fiscal year. The guidance allows for the Corporation to apply this election prospectively to all new and existing servicing assets and servicing liabilities. Management believes this election will provide more comparable results to peers as many of those within our industry group account for loan servicing rights under the fair value method. The change in accounting policy in the first quarter of 2017 results in a cumulative adjustment to increase retained earnings in the amount of $3.7 million , net of taxes. Investment Securities The Corporation has elected to early adopt Accounting Standards Update ("ASU") No. 2017-08, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities ("ASU 2017-08") during the second quarter of 2017. The guidance in ASU 2017-08 shortens the amortization period for certain callable debt securities that are held at a premium to the earliest call date. Debt securities held at a discount will continue to be amortized as a yield adjustment over the life of the instrument. The early adoption of ASU 2017-08 in the second quarter of 2017 did not have a material impact on the consolidated financial statements.

Mergers and Acquisitions

Mergers and Acquisitions	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Mergers and Acquisitions	Mergers and Acquisitions Merger with Talmer Bancorp, Inc. On August 31, 2016, the Corporation completed a merger with Talmer Bancorp, Inc. ("Talmer") for total consideration of $1.61 billion . As a result of the merger, the Corporation issued 32.1 million shares of its common stock based on an exchange ratio where each Talmer shareholder received 0.4725 shares of the Corporation's common stock, and $1.61 in cash, for each share of Talmer common stock. In conjunction with the merger, the Corporation entered into and drew on a $125.0 million credit facility. The proceeds from the credit facility were used to pay off the Corporation's $25.0 million line-of-credit and a $37.5 million line-of-credit of Talmer, with the remaining proceeds used to partially fund the cash portion of the merger consideration. The Corporation incurred $4.6 million and $5.6 million of merger and acquisition-related transaction expenses during the six months ended June 30, 2017 and 2016 , respectively, primarily related to the merger with Talmer. As a result of the merger, Talmer Bank and Trust became a wholly-owned subsidiary of the Corporation. Talmer Bank and Trust was consolidated with and into Chemical Bank during the fourth quarter of 2016. The Corporation determined that the merger with Talmer constitutes a business combination as defined by ASC 805. Accordingly, the assets acquired and liabilities assumed were recorded at their fair values on the date of acquisition. Fair values were determined in accordance with the guidance provided in ASC Topic 820, Fair Value Measurements. In many cases the determination of the fair values required management to make estimates about discount rates, future expected cash flows, market conditions and other future events that are highly subjective in nature and subject to change. The following allocation is based on the information that was available to make preliminary estimates of the fair value and may change as additional information becomes available and additional analyses are completed. While the Corporation believes that information provided a reasonable basis for estimating the fair values, it expects that it could obtain additional information and evidence during the measurement period that may result in changes to the estimated fair value amounts. This measurement period ends on the earlier of one year after the merger date or the date we receive the information about the facts and circumstances that existed at the merger date. Subsequent adjustments, if necessary, will be reflected in future filings. These refinements include: (1) changes in the estimated fair value of loans acquired: (2) changes in the estimated fair value of intangible assets acquired: (3) changes in deferred tax assets related to fair value estimates and a change in the expected realization of items considered to be net operating loss carry forwards and (4) a change in the goodwill caused by the net effect of these adjustments. The following table presents the allocation of fair value at the merger date: (Dollars in thousands) Consideration paid: Stock $ 1,504,811 Cash 107,638 Total consideration 1,612,449 Fair value of identifiable assets acquired: Cash and cash equivalents 433,352 Investment securities: Available-for-sale 808,894 Held-to-maturity 1,657 Loans held-for-sale 244,916 Loans 4,882,402 Premises and equipment 38,793 Loan servicing rights 42,462 Other intangible assets 19,088 Interest receivable and other assets 395,119 Total identifiable assets acquired $ 6,866,683 Fair value of liabilities assumed: Noninterest-bearing deposits 1,236,902 Interest-bearing deposits 4,057,716 Interest payable and other liabilities 99,482 Securities sold under agreements to repurchase with customers 19,704 Short-term borrowings 387,500 Long-term borrowings 299,597 Total liabilities assumed $ 6,100,901 Fair value of net identifiable assets acquired $ 765,782 Goodwill resulting from acquisition $ 846,667 Information regarding loans accounted for under ASC 310-30 at the merger date is as follows: (Dollars in thousands) Accounted for under ASC 310-30: Contractual cash flows $ 5,968,488 Contractual cash flows not expected to be collected (nonaccretable difference) 223,959 Expected cash flows 5,744,529 Interest component of expected cash flows (accretable yield) 862,127 Fair value at acquisition $ 4,882,402 Unaudited Pro Forma Combined Results of Operations The following unaudited pro forma financial information presents the consolidated results of operation of the Corporation and Talmer as if the merger had occurred as of January 1, 2016. The unaudited pro forma combined results of operations are presented solely for information purposes and are not intended to represent or be indicative of the consolidated results of operations that Chemical would have reported had these transactions been completed as of the dates and for the periods presented, nor are they necessarily indicative of future results. In particular, no adjustments have been made to eliminate the amount of Talmer's provision for loan losses incurred prior to the acquisition date that would not have been necessary had the acquired loans been recorded at fair value as of the beginning of each period indicated. In accordance with Article 11 of SEC Regulation S-X, transaction costs directly attributable to the acquisitions have been excluded. Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) (1) 2017 2016 2017 2016 Net interest and other income $ 179,516 $ 168,130 $ 347,623 $ 326,100 Net Income 52,014 42,111 99,618 81,163 Earnings per share: Basic $ 0.73 $ 0.60 $ 1.41 $ 1.15 Diluted 0.73 0.59 1.39 1.14 (1) As the business combination was effective August 31, 2016, there were no proforma adjustments for the three and six months ended June 30, 2017 .

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2017
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 — available-for-sale, loans held-for-sale, loan servicing rights 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 1 valuations for the Corporation include U.S. Treasury securities that are traded by dealers or brokers in active over-the-counter markets. Valuations are obtained from a third-party pricing service for these investment securities. 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 sponsored agency securities, including securities issued by the Federal Home Loan Bank, 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, preferred stock 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 securities issued by certain state and political subdivisions, held-to-maturity trust preferred investment securities, impaired loans, goodwill, core deposit intangible assets, non-compete 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 classified as available-for-sale are recorded at fair value on a recurring basis. 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 has 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: Effective January 1, 2017, the Corporation elected to account for all LSRs under the fair value measurement method. LSRs acquired related to the merger with Talmer effective August 31, 2016 were also previously accounted for under the fair value measurement method based on accounting election. 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, 2017 and December 31, 2016 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 (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total June 30, 2017 Investment securities – available-for-sale: U.S. Treasury securities $ 5,793 $ — $ — $ 5,793 Government sponsored agencies — 247,474 — 247,474 State and political subdivisions — 292,035 — 292,035 Residential mortgage-backed securities — 292,912 — 292,912 Collateralized mortgage obligations — 733,187 — 733,187 Corporate bonds — 158,168 — 158,168 Preferred stock and trust preferred securities — 37,909 — 37,909 Total investment securities – available-for-sale 5,793 1,761,685 — 1,767,478 Loans held-for-sale — 65,371 — 65,371 Loan servicing rights — — 64,522 64,522 Derivative assets: Customer-initiated derivatives — 8,636 — 8,636 Forward contracts related to mortgage loans to be delivered for sale — 617 — 617 Interest rate lock commitments — 1,997 — 1,997 Power Equity CD — 2,062 — 2,062 Risk management derivatives — 224 — 224 Total derivatives — 13,536 — 13,536 Total assets at fair value $ 5,793 $ 1,840,592 $ 64,522 $ 1,910,907 Derivative liabilities: Customer-initiated derivatives — 9,152 — 9,152 Power Equity CD — 2,062 — 2,062 Risk management derivatives — 282 — 282 Total derivatives — 11,496 — 11,496 Total liabilities at fair value $ — $ 11,496 $ — $ 11,496 December 31, 2016 Investment securities – available-for-sale: U.S. Treasury securities $ 5,793 $ — $ — $ 5,793 Government sponsored agencies — 215,011 — 215,011 State and political subdivisions — 300,088 — 300,088 Residential mortgage-backed securities — 272,282 — 272,282 Collateralized mortgage obligations — 320,025 — 320,025 Corporate bonds — 89,474 — 89,474 Preferred stock and trust preferred securities — 32,291 — 32,291 Total investment securities – available-for-sale 5,793 1,229,171 — 1,234,964 Loans held-for-sale — 81,830 — 81,830 Loan servicing rights — — 48,085 48,085 Derivative assets: Customer-initiated derivatives — 4,406 — 4,406 Forward contracts related to mortgage loans to be delivered for sale — 635 — 635 Interest rate lock commitments — 956 — 956 Power Equity CD — 2,218 — 2,218 Total derivatives — 8,215 — 8,215 Total assets at fair value $ 5,793 $ 1,319,216 $ 48,085 $ 1,373,094 Derivative liabilities: Customer-initiated derivatives — 4,141 — 4,141 Power Equity CD — 2,218 — 2,218 Total derivatives — 6,359 — 6,359 Total liabilities at fair value $ — $ 6,359 $ — $ 6,359 There were no transfers between levels within the fair value hierarchy during the three or six months ended June 30, 2017 . The following table summarizes the changes in Level 3 assets measured at fair value on a recurring basis. Three Months Ended June 30, 2017 Six Months Ended June 30, 2017 (Dollars in thousands) Loan servicing rights Balance, beginning of period $ 64,604 $ 48,085 Transfer in based on new accounting policy election (1) — 15,891 Gains (losses): Recorded in earnings (realized): Recorded in "Net gain on sale of loans and other mortgage banking revenue" (2,466 ) (3,591 ) New originations 2,384 4,137 Balance, end of period $ 64,522 $ 64,522 (1) Refer to Note 1, Basis of Presentation and Significant Accounting Policies, for further details. 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, 2017 and December 31, 2016 . 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, 2017 December 31, 2016 Aggregate fair value $ 65,371 $ 81,830 Contractual balance 63,162 81,009 Unrealized gain (loss) 2,209 821 The total amount of gains (losses) from loans held-for-sale included in the Consolidated Statements of Income were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2017 2016 2017 2016 Interest income (1) $ 463 $ 20 $ 1,014 $ 39 Change in fair value (2) 787 — 1,388 — Net gain on sales of loans (2) 13,905 2,135 20,025 3,431 Total included in earnings $ 15,155 $ 2,155 $ 22,427 $ 3,470 (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. 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 appraised value, discounts ranging between 10% and 25% 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, 2017 and December 31, 2016 , no goodwill was impaired. Other intangible assets: Other intangible assets consist of core deposit intangible assets and non-compete intangible assets. These items are recorded at fair value when initially recorded. Subsequently, core deposit intangible assets and non-compete intangible assets are amortized primarily on an accelerated basis over periods ranging from ten to fifteen years for core deposit intangible assets and one year for non-compete intangible assets 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 or non-compete intangible asset impairment is identified, the Corporation classifies impaired core deposit intangible assets and impaired non-compete intangible assets subject to nonrecurring fair value measurements as Level 3 valuations. At June 30, 2017 and December 31, 2016 , there was no impairment identified for core deposit intangible assets or non-compete intangible assets. Loan servicing rights: Prior to January 1, 2017, LSRs originated by the Corporation and those acquired in acquisitions of other institutions prior to the merger with Talmer were accounted for under the amortization method. The fair value of these LSRs were initially estimated using a model that calculates the net present value of estimated future cash flows using various assumptions, including prepayment speeds, the discount rate and servicing costs. If the valuation model reflected a value less than the carrying value, LSRs were adjusted to fair value, as determined by the model, through a valuation allowance. The Corporation classified the LSRs subject to nonrecurring fair value measurements as Level 3 valuations. At December 31, 2016 , the Corporation recognized a valuation allowance of $8 thousand related to impairment within certain pools attributable to the Corporation's servicing portfolios. As a result, the LSRs related to these servicing portfolios were considered to be recorded at fair value on a nonrecurring basis as of December 31, 2016 . 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 10% and 25% 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 For assets measured at fair value on a nonrecurring basis, quantitative disclosures about fair value measurements for each major category of assets follows: (Dollars in thousands) Significant Unobservable Inputs (Level 3) Total June 30, 2017 Impaired originated loans $ 63,694 $ 63,694 Other real estate/repossessed assets 3,811 3,811 Total $ 67,505 $ 67,505 December 31, 2016 Impaired originated loans $ 62,184 $ 62,184 Other real estate/repossessed assets 1,386 1,386 Loan servicing rights 2 2 Total $ 63,572 $ 63,572 There were no liabilities recorded at fair value on a nonrecurring basis at June 30, 2017 and December 31, 2016 . 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 June 30, 2017 Valuation Technique Significant Unobservable Inputs Range Impaired originated loans $ 63,694 Appraisal of collateral Discount for type of collateral and age of appraisal 10%-25% Other real estate/repossessed assets 3,811 Appraisal of property Discount for type of property and age of appraisal 10%-25% 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. However, the method of estimating fair value for certain financial instruments, such as loans, that are not required to be measured on a recurring or nonrecurring basis, as prescribed by FASB ASC Topic 820, "Fair Value Measurement", does not incorporate the exit-price concept of fair value. 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 present value methods using unobservable inputs requiring management's judgment to estimate the fair values of its financial instruments, which are considered Level 3 valuations. These Level 3 valuations are affected by the assumptions made and, accordingly, do not necessarily indicate amounts that could 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. The methodologies for estimating the fair value of financial assets and financial liabilities on a recurring or nonrecurring basis are discussed above. At June 30, 2017 and December 31, 2016 , the estimated fair values of cash and cash equivalents, interest receivable and interest payable approximated their carrying values at those dates. The methodologies for other financial assets and financial liabilities follow. Investment securities — held-to-maturity : Fair value measurements for investment securities — held-to-maturity fair values are 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. Fair value measurements using Level 2 valuations of investment securities — held-to-maturity includes investment securities issued by state and political subdivisions. Level 3 valuations include trust preferred investment securities. Nonmarketable equity securities: Fair value measurements of nonmarketable equity securities, which consist of Federal Home Loan Bank (FHLB) and Federal Reserve Bank (FRB) stock, are based on their redeemable value, which is cost. The market for these securities is restricted to the issuer of the stock and subject to impairment evaluation. It is not practicable to determine the fair value of these securities within the fair value hierarchy due to the restrictions placed on their transferability. Loans: The fair values of loans that are not considered impaired are estimated using a discounted cash flow model. The cash flows take into consideration current portfolio interest rates and repricing characteristics as well as assumptions relating to prepayment speeds. The discount rates take into consideration the current market interest rate environment, a credit risk component based on the credit characteristics of each loan portfolio, and a liquidity premium reflecting the liquidity or illiquidity of the market. The fair value measurements for loans are Level 3 valuations. Bank-owned life insurance: Life insurance policies are held on certain officers. The carrying value of these policies approximates fair value as it is based on the cash surrender value adjusted for other charges or amounts due that are probable at settlement. As such, the Corporation classifies the estimated fair value of bank-owned life insurance as Level 2. Bank-owned life insurance is recorded within "Interest receivable and other assets." Deposits: The fair values of deposit accounts without defined maturities, such as interest- and noninterest-bearing checking, savings and money market accounts, are estimated to be the amounts payable on demand. The fair values for variable-interest rate time deposits with defined maturities approximate their carrying amounts. Fair value measurements for fixed-interest rate time deposits with defined maturities are based on the discounted value of contractual cash flows, using the Corporation’s interest rates currently being offered for deposits of similar maturities, and are therefore classified as Level 2 valuations. However, if the estimated fair value is less than the carrying value, the carrying value is reported as the fair value. Securities sold under agreements to repurchase: Fair value measurements are based on the present value of future estimated cash flows using current interest rates offered to the Corporation under similar terms and are Level 2 valuations. Short-term borrowings: Short-term borrowings consist of short-term FHLB advances. Fair value measurements for short-term borrowings are based on the present value of future estimated cash flows using current interest rates offered to the Corporation for debt with similar terms and are Level 2 valuations. Lon g -term borrowings: Long-term borrowings consist of long-term FHLB advances, securities sold under agreements to repurchase with an unaffiliated financial institution, a term line-of-credit and subordinated debt obligations. Fair value measurements for long-term borrowings are based on the present value of future estimated cash flows using current interest rates offered to the Corporation for debt with similar terms and are therefore classified as Level 2 valuations. Financial guarantees : The Corporation’s unused commitments to extend credit, standby letters of credit and loan commitments have no carrying amount and have been estimated to have no realizable fair value. Historically, a majority of the unused commitments to extend credit have not been drawn upon and, generally, the Corporation does not receive fees in connection with these commitments other than standby letter of credit fees, which are not significant. 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 was as follows: Level in Fair Value Measurement Hierarchy June 30, 2017 December 31, 2016 (Dollars in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial assets: Cash and cash equivalents Level 1 $ 619,241 $ 619,241 $ 474,402 $ 474,402 Investment securities: Held-to-maturity Level 2 645,105 639,683 622,927 608,221 Held-to-maturity Level 3 500 360 500 310 Nonmarketable equity securities Level 2 180,196 180,196 97,350 97,350 Net loans (1) Level 3 13,583,575 13,758,368 12,912,511 13,069,315 Interest receivable Level 2 45,832 45,832 42,235 42,235 Bank-owned life insurance Level 2 145,671 145,671 143,718 143,718 Financial liabilities: Deposits: Deposits without defined maturities Level 2 $ 10,217,235 $ 10,217,235 $ 9,862,755 $ 9,862,755 Time deposits Level 2 2,987,132 2,987,779 3,010,367 3,010,048 Total deposits 13,204,367 13,205,014 12,873,122 12,872,803 Interest payable Level 2 5,112 5,112 5,415 5,415 Securities sold under agreements to repurchase with customers Level 2 310,042 310,042 343,047 343,047 Short-term borrowings Level 2 2,050,000 2,048,744 825,000 825,000 Long-term borrowings Level 2 435,852 431,345 597,847 591,227 (1) Included $63.7 million and $62.2 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2017 and December 31, 2016 , respectively.

Investment Securities

Investment Securities	6 Months Ended
	Jun. 30, 2017
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 available-for-sale and investment securities held-to-maturity at June 30, 2017 and December 31, 2016 : Investment Securities Available-for-Sale (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2017 U.S. Treasury securities $ 5,795 $ — $ 2 $ 5,793 Government sponsored agencies 248,021 619 1,166 247,474 State and political subdivisions 297,560 114 5,639 292,035 Residential mortgage-backed securities 296,898 26 4,012 292,912 Collateralized mortgage obligations 737,963 173 4,949 733,187 Corporate bonds 158,828 276 936 158,168 Preferred stock and trust preferred securities 36,070 1,871 32 37,909 Total $ 1,781,135 $ 3,079 $ 16,736 $ 1,767,478 December 31, 2016 U.S. Treasury securities $ 5,788 $ 5 $ — $ 5,793 Government sponsored agencies 216,890 189 2,068 215,011 State and political subdivisions 311,704 163 11,779 300,088 Residential mortgage-backed securities 276,162 112 3,992 272,282 Collateralized mortgage obligations 323,965 63 4,003 320,025 Corporate bonds 90,859 16 1,401 89,474 Preferred stock and trust preferred securities 31,353 1,018 80 32,291 Total $ 1,256,721 $ 1,566 $ 23,323 $ 1,234,964 Investment Securities Held-to-Maturity (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2017 State and political subdivisions $ 645,105 $ 5,281 $ 10,703 $ 639,683 Trust preferred securities 500 — 140 360 Total $ 645,605 $ 5,281 $ 10,843 $ 640,043 December 31, 2016 State and political subdivisions $ 622,927 $ 2,648 $ 17,354 $ 608,221 Trust preferred securities 500 — 190 310 Total $ 623,427 $ 2,648 $ 17,544 $ 608,531 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 securities 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) 2017 2016 2017 2016 Proceeds $ 10,050 $ 4,356 $ 10,050 $ 5,000 Gross gains 77 18 167 37 The following is a summary of the amortized cost and fair value of investment securities at June 30, 2017 , by maturity, for both available-for-sale and held-to-maturity investment securities. 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, 2017 (Dollars in thousands) Amortized Cost Fair Value Investment Securities Available-for-Sale: Due in one year or less $ 345,833 $ 344,064 Due after one year through five years 731,523 726,231 Due after five years through ten years 488,832 485,107 Due after ten years 213,558 210,229 Preferred stock 1,389 1,847 Total $ 1,781,135 $ 1,767,478 Investment Securities Held-to-Maturity: Due in one year or less $ 85,434 $ 85,398 Due after one year through five years 253,002 251,488 Due after five years through ten years 143,396 141,140 Due after ten years 163,773 162,017 Total $ 645,605 $ 640,043 Securities with a carrying value of $1.05 billion and $794.0 million were pledged at June 30, 2017 and December 31, 2016 , respectively, to secure borrowings and deposits. At June 30, 2017 and December 31, 2016 , 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 both available-for-sale and held-to-maturity investment securities with gross unrealized losses at June 30, 2017 and December 31, 2016 , aggregated by category and length of time that individual securities have been in a continuous unrealized loss position. As of June 30, 2017 , the Corporation’s securities portfolio consisted of 2,336 securities, 1,351 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, 2017 U.S. Treasury securities $ 5,793 $ 2 $ — $ — $ 5,793 $ 2 Government sponsored agencies 104,655 1,042 10,816 124 115,471 1,166 State and political subdivisions 614,276 15,504 46,588 838 660,864 16,342 Residential mortgage-backed securities 284,277 4,012 — — 284,277 4,012 Collateralized mortgage obligations 627,054 4,765 11,061 184 638,115 4,949 Corporate bonds 111,931 935 1,499 1 113,430 936 Trust preferred securities 3,843 32 360 140 4,203 172 Total $ 1,751,829 $ 26,292 $ 70,324 $ 1,287 $ 1,822,153 $ 27,579 December 31, 2016 Government sponsored agencies $ 105,702 $ 1,707 $ 15,023 $ 361 $ 120,725 $ 2,068 State and political subdivisions 758,063 28,158 26,810 975 784,873 29,133 Residential mortgage-backed securities 244,239 3,992 — — 244,239 3,992 Collateralized mortgage obligations 279,001 3,778 14,754 225 293,755 4,003 Corporate bonds 80,536 1,401 — — 80,536 1,401 Trust preferred securities 10,699 80 310 190 11,009 270 Total $ 1,478,240 $ 39,116 $ 56,897 $ 1,751 $ 1,535,137 $ 40,867 An assessment is performed quarterly by the Corporation to determine whether unrealized losses in its investment 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 investment security, as of June 30, 2017 , represented 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 investment securities at June 30, 2017 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, 2017 , the Corporation did not have the intent to sell any of its impaired investment securities and believed that it was more-likely-than-not that the Corporation will not have to sell any such investment securities before a full recovery of amortized cost. Accordingly, at June 30, 2017 , the Corporation believed the impairments in its investment 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, 2017
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, non-owner occupied real estate leased to one or more tenants and vacant land that has been acquired for investment or future land development. 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, 2017 and December 31, 2016 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 personal watercraft and comprised primarily of indirect loans purchased from dealers. These loans 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. 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, 2017 Commercial loan portfolio: Commercial $ 2,184,283 $ 1,175,878 $ 3,360,161 Commercial real estate 2,405,772 1,918,551 4,324,323 Real estate construction and land development 349,395 97,283 446,678 Subtotal 4,939,450 3,191,712 8,131,162 Consumer loan portfolio: Residential mortgage 1,683,550 1,441,847 3,125,397 Consumer installment 1,429,088 124,879 1,553,967 Home equity 607,534 249,312 856,846 Subtotal 3,720,172 1,816,038 5,536,210 Total loans $ 8,659,622 $ 5,007,750 $ 13,667,372 (2) December 31, 2016 Commercial loan portfolio: Commercial $ 1,901,526 $ 1,315,774 $ 3,217,300 Commercial real estate 1,921,799 2,051,341 3,973,140 Real estate construction and land development 281,724 122,048 403,772 Subtotal 4,105,049 3,489,163 7,594,212 Consumer loan portfolio: Residential mortgage 1,475,342 1,611,132 3,086,474 Consumer installment 1,282,588 151,296 1,433,884 Home equity 595,422 280,787 876,209 Subtotal 3,353,352 2,043,215 5,396,567 Total loans $ 7,458,401 $ 5,532,378 $ 12,990,779 (2) (1) Acquired loans are accounted for under ASC 310-30. (2) Reported net of deferred costs totaling $20.0 million and $14.8 million at June 30, 2017 and December 31, 2016 , respectively. The Corporation acquired loans at fair value as of the acquisition date, which includes loans acquired in the acquisitions of Talmer, Lake Michigan Financial Corporation ("Lake Michigan"), Monarch Community Bancorp, Inc. ("Monarch"), Northwestern Bancorp, Inc. ("Northwestern") and O.A.K. Financial Corporation ("OAK"). Acquired loans are accounted for under ASC 310-30 which recognizes the expected shortfall of expected future cash flows, as compared to the contractual amount due, as nonaccretable discount. 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 discount is recognized over the expected remaining life of the acquired loans on a pool basis. Activity for the accretable yield, which includes contractually due interest 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, 2017 Balance at beginning of period $ 774,778 $ 113,211 $ 26,055 $ 64,897 $ 21,467 $ 1,000,408 Accretion recognized in interest income (45,091 ) (7,583 ) (1,159 ) (5,467 ) (3,314 ) (62,614 ) Net reclassification (to) from nonaccretable difference (1) 71,682 15,944 (626 ) 11,782 1,643 100,425 Balance at end of period $ 801,369 $ 121,572 $ 24,270 $ 71,212 $ 19,796 $ 1,038,219 Three Months Ended June 30, 2016 Balance at beginning of period $ — $ 137,975 $ 33,235 $ 76,368 $ 27,036 $ 274,614 Accretion recognized in interest income — (8,338 ) (1,385 ) (4,028 ) (3,727 ) (17,478 ) Net reclassification (to) from nonaccretable difference (1) — (4,294 ) (991 ) 1,406 3,283 (596 ) Balance at end of period $ — $ 125,343 $ 30,859 $ 73,746 $ 26,592 $ 256,540 Six Months Ended June 30, 2017 Balance at beginning of period $ 798,210 $ 121,416 $ 27,182 $ 69,847 $ 23,316 $ 1,039,971 Accretion recognized in interest income (89,662 ) (14,849 ) (2,340 ) (9,359 ) (6,591 ) (122,801 ) Net reclassification (to) from nonaccretable difference (1) 92,821 15,005 (572 ) 10,724 3,071 121,049 Balance at end of period $ 801,369 $ 121,572 $ 24,270 $ 71,212 $ 19,796 $ 1,038,219 Six Months Ended June 30, 2016 Balance at beginning of period $ — $ 152,999 $ 34,558 $ 82,623 $ 28,077 $ 298,257 Accretion recognized in interest income — (17,291 ) (2,836 ) (8,029 ) (6,284 ) (34,440 ) Net reclassification (to) from nonaccretable difference (1) — (10,365 ) (863 ) (848 ) 4,799 (7,277 ) Balance at end of period $ — $ 125,343 $ 30,859 $ 73,746 $ 26,592 $ 256,540 (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 and additional communities located within Northeast 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 $2.0 million requiring group loan authority approval, except for six executive and senior officers who have varying loan limits exceeding $2.0 million and up to $3.5 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 $2.0 million to $5.0 million , and a senior loan committee, consisting of certain executive and senior officers, that meets weekly to consider loans ranging in amounts from $5.0 million to $10.0 million , depending on risk rating and credit action required. A directors’ loan committee of Chemical Bank, consisting of eight independent directors of Chemical Bank, the chief executive officer of Chemical Bank and the chief credit officer of Chemical Bank, meets bi-weekly to consider loans in amounts over $10.0 million , and certain loans under $10.0 million depending on a loan’s risk rating and credit action required. Loans over $25.0 million 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, 2017 and December 31, 2016 : (Dollars in thousands) Pass Special Mention Substandard Doubtful Total June 30, 2017 Originated Portfolio: Commercial $ 2,101,781 $ 31,051 $ 47,871 $ 3,580 $ 2,184,283 Commercial real estate 2,341,493 29,840 33,390 1,049 2,405,772 Real estate construction and land development 349,339 — 56 — 349,395 Subtotal 4,792,613 60,891 81,317 4,629 4,939,450 Acquired Portfolio: Commercial 1,100,238 30,686 44,951 3 1,175,878 Commercial real estate 1,777,461 62,807 78,118 165 1,918,551 Real estate construction and land development 93,301 1,941 2,041 — 97,283 Subtotal 2,971,000 95,434 125,110 168 3,191,712 Total $ 7,763,613 $ 156,325 $ 206,427 $ 4,797 $ 8,131,162 December 31, 2016 Originated Portfolio: Commercial $ 1,803,750 $ 44,809 $ 51,898 $ 1,069 $ 1,901,526 Commercial real estate 1,849,315 36,981 35,502 1 1,921,799 Real estate construction and land development 280,968 157 599 — 281,724 Subtotal 3,934,033 81,947 87,999 1,070 4,105,049 Acquired Portfolio: Commercial 1,218,848 46,643 50,283 — 1,315,774 Commercial real estate 1,897,011 61,441 92,636 253 2,051,341 Real estate construction and land development 117,505 1,982 2,561 — 122,048 Subtotal 3,233,364 110,066 145,480 253 3,489,163 Total $ 7,167,397 $ 192,013 $ 233,479 $ 1,323 $ 7,594,212 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, 2017 and December 31, 2016 : (Dollars in thousands) Residential Mortgage Consumer Installment Home Equity Total Consumer June 30, 2017 Originated Loans: Performing $ 1,675,836 $ 1,428,331 $ 603,663 $ 3,707,830 Nonperforming 7,714 757 3,871 12,342 Subtotal 1,683,550 1,429,088 607,534 3,720,172 Acquired Loans 1,441,847 124,879 249,312 1,816,038 Total $ 3,125,397 $ 1,553,967 $ 856,846 $ 5,536,210 December 31, 2016 Originated Loans: Performing $ 1,468,373 $ 1,281,709 $ 592,071 $ 3,342,153 Nonperforming 6,969 879 3,351 11,199 Subtotal 1,475,342 1,282,588 595,422 3,353,352 Acquired Loans 1,611,132 151,296 280,787 2,043,215 Total $ 3,086,474 $ 1,433,884 $ 876,209 $ 5,396,567 Nonperforming Assets and Past Due Loans Nonperforming assets consist of loans for which the accrual of interest has been discounted, 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 loans follows: (Dollars in thousands) June 30, December 31, Nonperforming assets Nonaccrual loans: Commercial $ 18,773 $ 13,178 Commercial real estate 19,723 19,877 Real estate construction and land development 56 80 Residential mortgage 7,714 6,969 Consumer installment 757 879 Home equity 3,871 3,351 Total nonaccrual loans 50,894 44,334 Other real estate owned and repossessed assets 14,582 17,187 Total nonperforming assets $ 65,476 $ 61,521 Accruing loans contractually past due 90 days or more as to interest or principal payments, excluding acquired loans accounted for under ASC 310-30 Commercial 58 11 Commercial real estate 262 277 Home equity 2,026 995 Total accruing loans contractually past due 90 days or more as to interest or principal payments, excluding acquired loans accounted for under ASC 310-30 $ 2,346 $ 1,283 The Corporation’s nonaccrual loans at June 30, 2017 and December 31, 2016 included $25.7 million and $30.5 million , respectively, of nonaccrual TDRs. The Corporation had $4.6 million of residential mortgage loans that were in the process of foreclosure at June 30, 2017 , compared to $7.3 million at December 31, 2016 . Loan delinquency, excluding acquired loans accounted for under ASC 310-30, was as follows: (Dollars in thousands) 30-59 days past due 60-89 days past due 90 days or more past due Total past due Current Total loans 90 days or more past due and still accruing June 30, 2017 Originated Portfolio: Commercial $ 6,578 $ 5,408 $ 7,604 $ 19,590 $ 2,164,693 $ 2,184,283 $ 58 Commercial real estate 21,106 7,518 5,221 33,845 2,371,927 2,405,772 262 Real estate construction and land development — — — — 349,395 349,395 — Residential mortgage 411 2,607 1,418 4,436 1,679,114 1,683,550 — Consumer installment 2,553 363 156 3,072 1,426,016 1,429,088 — Home equity 3,798 1,095 2,775 7,668 599,866 607,534 2,026 Total $ 34,446 $ 16,991 $ 17,174 $ 68,611 $ 8,591,011 $ 8,659,622 $ 2,346 December 31, 2016 Originated Portfolio: Commercial $ 10,421 $ 4,842 $ 3,641 $ 18,904 $ 1,882,622 $ 1,901,526 $ 11 Commercial real estate 6,551 1,589 5,165 13,305 1,908,494 1,921,799 277 Real estate construction and land development 2,721 499 — 3,220 278,504 281,724 — Residential mortgage 3,147 62 1,752 4,961 1,470,381 1,475,342 — Consumer installment 3,991 675 238 4,904 1,277,684 1,282,588 — Home equity 3,097 893 2,349 6,339 589,083 595,422 995 Total $ 29,928 $ 8,560 $ 13,145 $ 51,633 $ 7,406,768 $ 7,458,401 $ 1,283 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, 2017 and December 31, 2016 : (Dollars in thousands) Recorded Investment Unpaid Principal Balance Related Valuation Allowance June 30, 2017 Impaired loans with a valuation allowance: Commercial $ 28,623 $ 31,419 $ 4,335 Commercial real estate 20,209 25,552 1,334 Real estate construction and land development 189 189 4 Residential mortgage 16,711 16,711 724 Consumer installment 851 851 88 Home equity 4,658 4,658 1,062 Subtotal 71,241 79,380 7,547 Impaired loans with no related valuation allowance: Commercial 7,677 9,761 — Commercial real estate 21,512 25,411 — Real estate construction and land development 56 56 — Residential mortgage 4,386 4,386 — Home equity 1,258 1,258 — Subtotal 34,889 40,872 — Total impaired loans: Commercial 36,300 41,180 4,335 Commercial real estate 41,721 50,963 1,334 Real estate construction and land development 245 245 4 Residential mortgage 21,097 21,097 724 Consumer installment 851 851 88 Home equity 5,916 5,916 1,062 Total $ 106,130 $ 120,252 $ 7,547 December 31, 2016 Impaired loans with a valuation allowance: Commercial $ 28,925 $ 33,209 $ 3,128 Commercial real estate 21,318 27,558 2,102 Real estate construction and land development 177 177 4 Residential mortgage 20,864 20,864 3,528 Consumer installment 879 879 240 Home equity 2,577 2,577 390 Subtotal 74,740 85,264 9,392 Impaired loans with no related valuation allowance: Commercial 7,435 11,153 — Commercial real estate 20,588 23,535 — Real estate construction and land development 80 80 — Residential mortgage 3,252 3,252 — Home equity 774 774 — Subtotal 32,129 38,794 — Total impaired loans: Commercial 36,360 44,362 3,128 Commercial real estate 41,906 51,093 2,102 Real estate construction and land development 257 257 4 Residential mortgage 24,116 24,116 3,528 Consumer installment 879 879 240 Home equity 3,351 3,351 390 Total $ 106,869 $ 124,058 $ 9,392 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, 2017 and 2016 , and the respective interest income amounts recognized: Three Months Ended June 30, 2017 Three Months Ended June 30, 2016 Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 (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 $ 24,493 $ 201 $ 3,867 $ — $ 25,103 $ 425 $ 7,209 $ — Commercial real estate 19,026 202 3,360 — 19,530 405 5,476 — Real estate construction and land development 141 3 — — 151 5 — — Residential mortgage 16,243 68 20,949 333 16,821 302 20,969 666 Consumer installment 682 1 — — 731 2 — — Home equity 4,024 16 — — 4,047 37 — — Subtotal $ 64,609 $ 491 $ 28,176 $ 333 $ 66,383 $ 1,176 $ 33,654 $ 666 Impaired loans with no related valuation allowance: Commercial $ 11,010 $ 48 $ 32,502 $ 310 $ 10,153 $ 78 $ 31,952 $ 587 Commercial real estate 25,183 99 45,679 312 24,329 203 45,708 692 Real estate construction and land development 106 — 860 2 93 — 889 8 Residential mortgage 4,581 10 5,094 — 4,194 17 5,121 — Consumer installment 142 — 281 — 179 — 311 — Home equity 1,162 5 1,984 — 1,021 6 2,186 — Subtotal $ 42,184 $ 162 $ 86,400 $ 624 $ 39,969 $ 304 $ 86,167 $ 1,287 Total impaired loans: Commercial $ 35,503 $ 249 $ 36,369 $ 310 $ 35,256 $ 503 $ 39,161 $ 587 Commercial real estate 44,209 301 49,039 312 43,859 608 51,184 692 Real estate construction and land development 247 3 860 2 244 5 889 8 Residential mortgage 20,824 78 26,043 333 21,015 319 26,090 666 Consumer installment 824 1 281 — 910 2 311 — Home equity 5,186 21 1,984 — 5,068 43 2,186 — Total $ 106,793 $ 653 $ 114,576 $ 957 $ 106,352 $ 1,480 $ 119,821 $ 1,953 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 $55.2 million and $62.5 million at June 30, 2017 and December 31, 2016 , 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, 2017 and 2016 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 Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2017 Commercial loan portfolio: Commercial $ 285 $ 266 $ — 7 $ 564 $ 551 Commercial real estate — 65 122 3 194 187 Subtotal 285 331 122 10 758 738 Consumer loan portfolio: Residential mortgage 37 261 — 5 316 298 Consumer installment 22 — — 4 24 22 Home equity 153 — — 4 160 153 Subtotal 212 261 — 13 500 473 Total loans $ 497 $ 592 $ 122 23 $ 1,258 $ 1,211 For the six months ended June 30, 2017 Commercial loan portfolio: Commercial $ 335 $ 1,367 $ 579 12 $ 2,303 $ 2,281 Commercial real estate 447 140 122 6 716 709 Subtotal 782 1,507 701 18 3,019 2,990 Consumer loan portfolio: Residential mortgage 135 261 — 6 414 396 Consumer installment 32 — — 6 35 32 Home equity 264 — — 5 325 264 Subtotal 431 261 — 17 774 692 Total loans $ 1,213 $ 1,768 $ 701 35 $ 3,793 $ 3,682 Concession type (Dollars in thousands) Principal Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2016 Commercial loan portfolio: Commercial $ 2,399 $ — $ 1,750 21 $ 4,149 $ 4,149 Commercial real estate 1,454 — — 2 1,454 1,454 Subtotal 3,853 — 1,750 23 5,603 5,603 Consumer loan portfolio: Residential mortgage 174 — — 2 174 174 Consumer installment 47 — — 8 47 47 Home equity 98 171 — 4 269 269 Subtotal 319 171 — 14 490 490 Total loans $ 4,172 $ 171 $ 1,750 37 $ 6,093 $ 6,093 For the six months ended June 30, 2016 Commercial loan portfolio: Commercial $ 6,231 $ — $ 1,750 28 $ 7,981 $ 7,981 Commercial real estate 2,441 — — 6 2,441 2,441 Subtotal 8,672 — 1,750 34 10,422 10,422 Consumer loan portfolio: Residential mortgage 279 — — 3 279 279 Consumer installment 80 — — 12 80 80 Home equity 127 208 — 6 335 335 Subtotal 486 208 — 21 694 694 Total loans $ 9,158 $ 208 $ 1,750 55 $ 11,116 $ 11,116 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, 2017 and December 31, 2016 : (Dollars in thousands) Accruing TDRs Nonaccrual TDRs Total June 30, 2017 Commercial loan portfolio $ 39,714 $ 21,296 $ 61,010 Consumer loan portfolio 15,522 4,409 19,931 Total $ 55,236 $ 25,705 $ 80,941 December 31, 2016 Commercial loan portfolio $ 45,388 $ 25,397 $ 70,785 Consumer loan portfolio 17,147 5,134 22,281 Total $ 62,535 $ 30,531 $ 93,066 The following schedule includes TDRs for which there was a payment default during the three and six months ended June 30, 2017 and 2016 , 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, 2017 For The Six Months Ended June 30, 2017 (Dollars in thousands) Number of loans Principal balance Number of loans Principal balance Commercial loan portfolio (commercial) 2 $ 997 5 $ 1,617 Consumer loan portfolio (residential mortgage) 3 58 5 163 Total 5 $ 1,055 10 $ 1,780 For The Three Months Ended June 30, 2016 For The Six Months Ended June 30, 2016 (Dollars in thousands) Number of loans Principal balance Number of loans Principal balance Commercial loan portfolio (commercial real estate) 1 $ 788 2 $ 1,721 Consumer loan portfolio (residential mortgage) 1 — 2 — Total 2 $ 788 4 $ 1,721 At June 30, 2017 , commitments to lend additional funds to borrowers whose terms have been modified in TDRs totaled $1.6 million . Allowance for Loan Losses The following schedule presents, by loan portfolio segment, the changes in the allowance for the three and six months ended June 30, 2017 and 2016 , and details regarding the balance in the allowance and the recorded investment in loans at June 30, 2017 by impairment evaluation method. (Dollars in thousands) Commercial Loan Portfolio Consumer Loan Portfolio Total Changes in allowance for loan losses for the three months ended June 30, 2017: Beginning balance $ 54,315 $ 24,459 $ 78,774 Provision for loan losses 4,084 2,145 6,229 Charge-offs (726 ) (1,578 ) (2,304 ) Recoveries 282 816 1,098 Ending balance $ 57,955 $ 25,842 $ 83,797 Changes in allowance for loan losses for the six months ended June 30, 2017: Beginning balance $ 51,201 $ 27,067 $ 78,268 Provision for loan losses 8,476 1,803 10,279 Charge-offs (3,417 ) (4,461 ) (7,878 ) Recoveries 1,695 1,433 3,128 Ending balance $ 57,955 $ 25,842 $ 83,797 Changes in allowance for loan losses for the three months ended June 30, 2016: Beginning balance $ 44,668 $ 25,650 $ 70,318 Provision for loan losses 900 2,100 3,000 Charge-offs (2,542 ) (1,078 ) (3,620 ) Recoveries 1,202 606 1,808 Ending balance $ 44,228 $ 27,278 $ 71,506 Changes in allowance for loan losses for the six months ended June 30, 2016: Beginning balance $ 47,234 $ 26,094 $ 73,328 Provision for loan losses 1,900 2,600 4,500 Charge-offs (6,438 ) (2,640 ) (9,078 ) Recoveries 1,532 1,224 2,756 Ending balance $ 44,228 $ 27,278 $ 71,506 Allowance for loan losses balance at June 30, 2017 attributable to: Loans individually evaluated for impairment $ 5,673 $ 1,874 $ 7,547 Loans collectively evaluated for impairment 52,282 23,968 76,250 Loans acquired with deteriorated credit quality — — — Total $ 57,955 $ 25,842 $ 83,797 Recorded investment (loan balance) at June 30, 2017: Loans individually evaluated for impairment $ 78,266 $ 27,864 $ 106,130 Loans collectively evaluated for impairment 4,861,184 3,692,308 8,553,492 Loans acquired with deteriorated credit quality 3,191,712 1,816,038 5,007,750 Total $ 8,131,162 $ 5,536,210 $ 13,667,372 The following schedule presents, by loan portfolio segment, details regarding the balance in the allowance and the recorded investment in loans at December 31, 2016 by impairment evaluation method. (Dollars in thousands) Commercial Loan Portfolio Consumer Loan Portfolio Total Allowance for loan losses balance at December 31, 2016 attributable to: Loans individually evaluated for i

Other Real Estate Owned and Rep

Other Real Estate Owned and Repossessed Assets	6 Months Ended
	Jun. 30, 2017
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, 2017 $ 16,812 $ 375 Other additions (1) 3,776 2,556 Net payments received (202 ) — Disposals (5,976 ) (1,986 ) Write-downs (773 ) — Balance at June 30, 2017 $ 13,637 $ 945 Balance at January 1, 2016 $ 9,716 $ 219 Other additions (1) 2,155 1,215 Net payments received (85 ) (764 ) Disposals (3,230 ) (556 ) Write-downs (230 ) — Balance at June 30, 2016 $ 8,326 $ 114 (1) Includes loans transferred to other real estate owned and other repossessed assets. At June 30, 2017 , the Corporation had $0.9 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 $4.6 million of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings are in process as of June 30, 2017 . Income and expenses related to other real estate owned and repossessed assets, recorded as a component of "Other expense" 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, 2017 Net gain (loss) on sale $ 768 $ (93 ) Write-downs (504 ) — Net operating expenses (710 ) (3 ) Total $ (446 ) $ (96 ) For the six months ended June 30, 2017 Net gain (loss) on sale $ 1,815 $ (171 ) Write-downs (773 ) — Net operating expenses (1,218 ) (6 ) Total $ (176 ) $ (177 ) For the three months ended June 30, 2016 Net gain (loss) on sale $ 1,320 $ 708 Write-downs (63 ) — Net operating expenses (260 ) 1 Total $ 997 $ 709 For the six months ended June 30, 2016 Net gain (loss) on sale $ 2,042 $ 700 Write-downs (230 ) — Net operating expenses (412 ) (3 ) Total $ 1,400 $ 697

Goodwill

Goodwill	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill	Goodwill Goodwill was $1.13 billion for both the periods ended June 30, 2017 and December 31, 2016 . Goodwill recorded is primarily attributable to the synergies and economies of scale expected from combining the operations of the Corporation and acquired organizations. The Corporation recorded goodwill in the amount of $846.7 million related to the merger with Talmer completed on August 31, 2016. Goodwill is not amortized but is evaluated at least annually for impairment. The Corporation’s most recent annual goodwill impairment review performed as of October 31, 2016 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, 2017 and that the Corporation's goodwill was no t impaired at June 30, 2017 .

Loan Servicing Rights

Loan Servicing Rights	6 Months Ended
	Jun. 30, 2017
Transfers and Servicing [Abstract]
Loan Servicing Rights	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 elected to account for LSRs acquired related to the merger with Talmer under the fair value measurement method. Prior to January 1, 2017, the Corporation accounted for all other LSRs at the lower of cost or fair value ("Amortized LSRs"). The Corporation elected as of January 1, 2017 to account for all previously Amortized LSRs under the fair value measurement method. This change in accounting policy resulted in a cumulative adjustment to retained earnings as of January 1, 2017 in the amount of $3.7 million . For further information on this election, refer to Note 1, Basis of Presentation and Significant Accounting Policies. 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, 2017 Fair value, beginning of period $ 320 $ 64,284 $ 64,604 Additions from loans sold with servicing retained 188 2,196 2,384 Changes in fair value due to: Reductions from pay-offs, pay downs and run-off (22 ) (642 ) (664 ) Changes in estimates of fair value (1) — (1,802 ) (1,802 ) Fair value, end of period $ 486 $ 64,036 $ 64,522 For the six months ended June 30, 2017 344 47741 48085 Fair value, beginning of period $ 344 $ 47,741 $ 48,085 Transfers based on new accounting policy election — 15,891 15,891 Additions from loans sold with servicing retained 188 3,949 4,137 Changes in fair value due to: 0 0 Reductions from pay-offs, pay downs and run-off (46 ) (1,224 ) (1,270 ) Changes in estimates of fair value (1) — (2,321 ) (2,321 ) Fair value, end of period $ 486 $ 64,036 $ 64,522 Principal balance of loans serviced for others that have servicing capitalized $ 47,349 $ 7,167,904 $ 7,215,253 (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. During the three and six months ended June 30, 2016 , the Corporation accounted for LSRs using the amortization method. Activity for LSRs and the related valuation allowance for the three and six months ended June 30, 2016 are as follows: (Dollars in thousands) For the Three Months Ended June 30, 2016 For the Six Months Ended June 30, 2016 Balance at beginning of period $ 10,478 $ 11,122 Additions 586 917 Amortization (975 ) (1,950 ) Change in valuation allowance (412 ) (412 ) Balance at end of period $ 9,677 $ 9,677 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, 2017 and December 31, 2016 . Mortgage As of June 30, 2017 Prepayment speed 0.0 - 35.7% Weighted average ("WA") discount rate 10.1 % Cost to service/per year $ 65 Ancillary income/per year $ 31 WA float range 1.2 % As of December 31, 2016 Prepayment speed 0.0 - 99.8% WA discount rate 10.1 % Cost to service/per year $65-$90 Ancillary income/per year $ 28 WA float range 1.0 % The Corporation realized total loan servicing fee income, included in "Net gain on sale of loans and other mortgage banking revenue" in the Consolidated Statements of Income, of $4.5 million and $1.3 million for the three months ended June 30, 2017 and 2016 , respectively, and $9.1 million and $2.6 million for the six months ended June 30, 2017 and 2016 , respectively.

Other Intangible Assets

Other Intangible Assets	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Other Intangible Assets	Other Intangible Assets The following table shows the net carrying value of the Corporation’s other intangible assets: (Dollars in thousands) June 30, December 31, Core deposit intangible assets $ 37,235 $ 40,211 Non-compete intangible assets 87 — Total other intangible assets $ 37,322 $ 40,211 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 $ 59,143 $ 59,143 Accumulated amortization 21,908 18,932 Net carrying amount $ 37,235 $ 40,211 Amortization expense recognized on core deposit intangible assets was $1.5 million and $1.1 million for the three months ended June 30, 2017 and 2016, respectively, and $3.0 million and $2.2 million for the six months ended June 30, 2017 and 2016, respectively. The estimated future amortization expense on core deposit intangible assets for periods ending after June 30, 2017 is as follows: 2017 — $3.0 million ; 2018 — $5.7 million ; 2019 — $5.4 million ; 2020 — $4.9 million ; 2021 — $4.5 million ; 2022 and thereafter — $13.8 million .

Derivative Instruments and Bala

Derivative Instruments and Balance Sheet Offsetting	6 Months Ended
	Jun. 30, 2017
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, customer-initiated derivatives, and, therefore, are not used for interest rate risk management purposes. 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. The Corporation utilizes interest rate swaps designated as cash flow hedges for risk management purposes to manage exposures that arise 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 effective portion of changes in fair value of derivatives designated and that qualify as cash flow hedges is recorded in accumulated other comprehensive income (loss) and is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. Any ineffective portion of the change in fair value of the derivatives is recognized directly in earnings. The Corporation's cash flow hedges had no amount of ineffectiveness included in net income during each period presented. The Corporation expects the hedges to remain fully 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, 2017 December 31, 2016 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 $ 400,000 $ 224 $ 282 $ — $ — $ — Total risk management purposes 400,000 224 282 — — — Customer-initiated and mortgage banking derivatives: Customer-initiated derivatives 1,055,917 8,636 9,152 600,598 4,406 4,141 Forward contracts related to mortgage loans to be delivered for sale 168,533 617 — 140,155 635 — Interest rate lock commitments 120,095 1,997 — 76,034 956 — Power Equity CD 38,540 2,062 2,062 36,807 2,218 2,218 Total customer-initiated and mortgage banking derivatives 1,383,085 13,312 11,214 853,594 8,215 6,359 Total gross derivatives $ 1,783,085 $ 13,536 $ 11,496 $ 853,594 $ 8,215 $ 6,359 (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 $538 thousand at June 30, 2017 and $99 thousand at December 31, 2016 . 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) 2017 2016 2017 2016 Forward contracts related to mortgage loans to be delivered for sale Net gain on sale of loans and other mortgage banking revenue $ 959 $ (409 ) $ (18 ) $ (642 ) Interest rate lock commitments Net gain on sale of loans and other mortgage banking revenue (181 ) 325 1,041 486 Customer-initiated derivatives Other noninterest income (551 ) — (781 ) — Total gain (loss) recognized in income $ 227 $ (84 ) $ 242 $ (156 ) 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, 2017 . (Dollars in thousands) Amount of gain (loss) recognized in other comprehensive income (Effective portion) Amount of gain (loss) reclassified from other comprehensive income to interest income or expense (Effective portion) Amount of gain (loss) recognized in other noninterest income (Ineffective portion) Three Months Ended June 30, 2017 Interest rate swaps designated as cash flow hedges $ (57 ) $ (409 ) $ — Six Months Ended June 30, 2017 Interest rate swaps designated as cash flow hedges $ (57 ) $ (409 ) $ — At June 30, 2017 , the Corporation expected $1.2 million of unrealized losses 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 (Dollars in thousands) Gross Gross amounts Net amounts Financial Collateral Net June 30, 2017 Offsetting derivative assets Derivative assets $ 8,838 $ — $ 8,838 $ — $ — $ 8,838 Offsetting derivative liabilities Derivative liabilities 9,434 — 9,434 — 9,037 397 December 31, 2016 Offsetting derivative assets Derivative assets $ 4,405 $ — $ 4,405 $ — $ — $ 4,405 Offsetting derivative liabilities Derivative liabilities 4,141 — 4,141 — 2,550 1,591

Investments in Qualified Afford

Investments in Qualified Affordable Housing Projects, Federal Historic Projects and New Market Tax Credits	6 Months Ended
	Jun. 30, 2017
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 are 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 $0.8 million and $0.6 million during the three months ended June 30, 2017 and 2016 , respectively, and $1.5 million and $1.2 million during the six months ended June 30, 2017 and 2016 , respectively. The Corporation's remaining investment in qualified affordable housing projects accounted for under the proportional amortization method totaled $36.2 million at June 30, 2017 and $29.5 million at December 31, 2016 . Under the equity method, the Corporation's share of the earnings or losses are included in "Other operating expenses" on the Consolidated Statements of Income. The Corporation's remaining investment in new market projects accounted for under the equity method totaled $20.2 million and $10.9 million at June 30, 2017 and December 31, 2016 , 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 $31.6 million and $16.0 million at June 30, 2017 and December 31, 2016 , 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. There were no impairment losses recognized as of June 30, 2017 or December 31, 2016 . 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 interests 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 Corporation's consolidated financial statements.

Commitments, Contingencies and

Commitments, Contingencies and Guarantees	6 Months Ended
	Jun. 30, 2017
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, 2017 and December 31, 2016 , the Corporation had $139.0 million and $118.9 million , respectively, of outstanding financial and performance standby letters of credit. The majority of these standby letters of credit are collateralized. The Corporation determined that there were no potential losses from standby letters of credit at June 30, 2017 and December 31, 2016 . 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, 2017 and December 31, 2016 , the Corporation had $2.93 billion and $2.70 billion , respectively, of commitments to extend credit. The Corporation had undisbursed loan commitments of $606.7 million and $578.2 million at June 30, 2017 and December 31, 2016 , 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 $1.1 million and $1.3 million at June 30, 2017 and December 31, 2016 , 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 Talmer, 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 $14.8 million and $16.9 million at June 30, 2017 and December 31, 2016 , 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 $14.2 million and $16.1 million at June 30, 2017 and December 31, 2016 , respectively. In the event of nonperformance, the Corporation has rights to the underlying collateral securing the loans. At both June 30, 2017 and December 31, 2016 , the Corporation had recorded a liability of $0.2 million in connection with the recourse agreements, recorded in "Interest payable and other liabilities" in the Consolidated Statements of Financial Position. Representations and Warranties In connection with the Corporation's mortgage banking loan sales, and the historical sales of Talmer, 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, 2017 and December 31, 2016 , respectively, the liability recorded in connection with these representations and warranties totaled $5.5 million and $6.5 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) 2017 2016 2017 2016 Reserve balance at beginning of period $ 5,689 $ 3,825 $ 6,459 $ 4,048 Reserve reduction (220 ) — (990 ) (150 ) Charge-offs — — — (73 ) Ending reserve balance $ 5,469 $ 3,825 $ 5,469 $ 3,825 (Dollars in thousands) June 30, 2017 December 31, 2016 Reserve balance Liability for specific claims $ 9 $ 730 General allowance 5,460 5,729 Total reserve balance $ 5,469 $ 6,459

Borrowings

Borrowings	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Borrowings	Borrowings A summary of the Corporation's short- and long-term borrowings follows: June 30, 2017 December 31, 2016 (Dollars in thousands) Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Securities sold under agreements to repurchase with customers: Securities sold under agreements to repurchase with customers $ 310,042 0.26 % $ 343,047 0.16 % Short-term borrowings: FHLB advances: 0.96% - 1.40% fixed-rate notes 2,050,000 1.02 825,000 0.65 Long-term borrowings: FHLB advances: 0.92% - 7.44% fixed-rate notes due 2017 to 2020 (2) 351,324 1.30 438,538 1.24 Securities sold under agreements to repurchase: 1.48% - 2.75% fixed-rate notes due in 2017 (3) 9,048 2.11 19,144 3.17 Line-of-credit: floating-rate based on one-month LIBOR plus 1.75% 59,854 2.80 124,625 2.52 Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035 (4) 11,354 3.42 11,285 3.14 Subordinated debt obligations: floating-rate based on three-month LIBOR plus 3.25% due in 2032 (5) 4,272 4.40 4,255 4.25 Total long-term borrowings 435,852 1.61 597,847 1.63 Total borrowings $ 2,795,894 1.03 % $ 1,765,894 0.89 % (1) Weighted average rate presented is the contractual rate which excludes premiums and discounts related to purchase accounting. (2) The June 30, 2017 balances include advances payable of $350.9 million and purchase accounting premiums of $0.5 million . The December 31, 2016 balance includes advances payable of $437.8 million and purchase accounting premiums of $0.7 million . (3) The June 30, 2017 balance includes advances payable of $9.0 million and purchase accounting premiums of $55 thousand . The December 31, 2016 balance includes advance payable of $19.0 million and purchase accounting premiums of $0.1 million . (4) The June 30, 2017 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.6 million . The December 31, 2016 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.7 million . (5) The June 30, 2017 balance includes advances payable of $5.0 million and purchase accounting discounts of $0.7 million . The December 31, 2016 balance includes advances payable of $5.0 million and purchase accounting discounts of $0.7 million . 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 $7.28 billion as of June 30, 2017 . 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 $50.0 million at June 30, 2017 . Securities sold under agreements to repurchase are with an unaffiliated financial institution and are secured by available for-sale-securities. The Corporation's securities sold under agreements to repurchase do not qualify as sales for accounting purposes. The remaining contractual maturity, excluding purchase accounting adjustments, of long-term securities under agreement to repurchase, is as follows: June 30, 2017 Remaining Contractual Maturities of the Agreements (Dollars in thousands) Overnight and continuous Up to 30 Days 30-90 Days Greater than 90 Days Total Securities sold under agreements to repurchase $ — $ — $ 4,000 $ 5,000 $ 9,000 Total borrowings $ — $ — $ 4,000 $ 5,000 $ 9,000 Amounts related to securities sold under agreements to repurchase not included in offsetting disclosure in Note 10 $ 9,000 The line-of-credit agreement contains certain restrictive covenants. The Corporation was in compliance with all of the covenants at June 30, 2017 .

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes The Corporation records its federal income tax expense using its estimate of the effective income tax rate expected for the full year and applies that rate on a year-to-date basis. The fluctuations in the Corporation's effective federal income tax rate reflect changes each period in the proportion of interest income exempt from federal taxation and other nondeductible expenses relative to pretax income and tax credits. A reconciliation of expected income tax expense at the federal statutory income tax rate and the amounts recorded in the Consolidated Financial Statements were as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 (Dollars in thousands) Amount Rate Amount Rate Amount Rate Amount Rate Tax at statutory rate $ 26,268 35.0 % $ 12,707 35.0 % $ 47,219 35.0 % $ 24,384 35.0 % Changes resulting from: Tax-exempt interest income (1,832 ) (2.4 ) (1,139 ) (3.1 ) (3,589 ) (2.7 ) (2,278 ) (3.3 ) State taxes, net of federal benefit 258 0.3 — — 470 0.4 — — Change in valuation allowance 38 — — — 49 — — — Bank-owned life insurance adjustments (335 ) (0.4 ) (287 ) (0.8 ) (679 ) (0.5 ) (355 ) (0.5 ) Income tax credits, net (1,102 ) (1.5 ) (834 ) (2.3 ) (1,797 ) (1.3 ) (1,631 ) (2.3 ) Tax benefits in excess of compensation costs on share-based payments (1) (248 ) (0.3 ) (68 ) (0.2 ) (6,382 ) (4.7 ) (411 ) (0.6 ) Other, net (11 ) — 153 0.4 2 — 580 0.8 Income tax expense $ 23,036 30.7 % $ 10,532 29.0 % $ 35,293 26.2 % $ 20,289 29.1 % (1) Represents excess tax benefits resulting from the exercise or settlement of share-based payment transactions.

Share-Based Compensation

Share-Based Compensation	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [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, 2017 and 2016 , share-based compensation expense related to share-based awards totaled $3.2 million and $1.0 million , respectively. During the six months ended June 30, 2017 and 2016 , share-based compensation expense related to share-based awards totaled $7.0 million and $1.8 million , respectively. The excess tax benefit realized from shared-based compensation transactions during the three months ended June 30, 2017 and 2016 was $248 thousand and $68 thousand , respectively, and during the six months ended June 30, 2017 and 2016 was $6.4 million and $411 thousand , respectively. During the six months ended June 30, 2017 , the Corporation granted options to purchase 126,691 shares of common stock, 162,771 restricted stock units and 13,500 shares of common stock to certain officers of the Corporation. On April 26, 2017, the shareholders of the Corporation approved the Stock Incentive Plan of 2017, which provides for 1,750,000 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, 2017 , there were 1,748,616 shares of common stock available for future grants under the Stock Incentive Plan of 2017. 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 2013 generally vest ratably over a three -year period. Stock options granted prior to 2016 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, 2017 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, 2016 407,939 $ 32.81 $ 6.15 2,453,395 $ 21.41 Granted 126,691 53.72 10.05 126,691 53.72 Exercised — — — (1,256,355 ) 16.19 Vested (81,584 ) 32.81 6.15 — — Forfeited/expired (10,337 ) 39.59 7.42 (10,337 ) 39.59 Outstanding at June 30, 2017 442,709 $ 38.64 $ 7.24 1,313,394 $ 29.39 Exercisable/vested at June 30, 2017 870,685 $ 24.68 The weighted-average remaining contractual terms were 6.8 years for all outstanding stock options and 5.7 years for exercisable stock options at June 30, 2017 . The intrinsic value of all outstanding in-the-money stock options and exercisable in-the-money stock options was $24.6 million and $20.7 million , respectively, at June 30, 2017 . The aggregate intrinsic values of outstanding and exercisable options at June 30, 2017 were calculated based on the closing market price of the Corporation’s common stock on June 30, 2017 of $48.41 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, 2016 was $11.2 million . Total cash received from options exercises during the six months ended June 30, 2017 and 2016 was $1.0 million and $0.7 million , respectively, resulting in the issuance of 511,144 shares and 47,758 shares, respectively. At June 30, 2017 , unrecognized compensation expense related to stock options totaled $3.0 million and is expected to be recognized over a remaining weighted average period of 4.1 years . The fair value of the stock options granted during the six months ended June 30, 2017 was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions. Expected dividend yield 3.32 % Risk-free interest rate 2.06 % Expected stock price volatility 26.9 % Expected life of options – in years 6.0 Weighted average fair value of options granted $ 10.05 The risk-free interest rate is based on the U.S. Treasury yield curve in effect at the time of grant and the expected life of the options granted. Expected stock volatility was based on historical volatility of the Corporation's common stock over the expected life of the option. The expected life of the options represents the period of time that options granted are expected to be outstanding and is based primarily upon historical experience, including option exercise behavior. Because of the unpredictability of the assumptions required, the Black-Scholes (or any other valuation) model is incapable of accurately predicting the Corporation's common stock price or of placing an accurate present value on options to purchase its stock. In addition, the Black-Scholes model was designed to approximate value for types of options that are very different from those issued by the Corporation. In spite of any theoretical value that may be placed on a stock option grant, no value is possible under options issued by the Corporation without an increase in the market price per share of the Corporation's common stock over the market price per share of the Corporation's common stock at the date of grant. Restricted Stock Units The Corporation grants restricted stock performance units and restricted stock service-based units (collectively referred to as restricted stock units) to certain officers from time to time. The restricted stock performance units vest based on the Corporation achieving certain performance target levels and the grantee completing the requisite service period. The restricted stock performance units 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 restricted stock performance units. The restricted stock service-based units vest upon satisfaction of a service condition. Upon achievement of the performance target level and/or satisfaction of a service condition, as applicable, the restricted stock units are converted into shares of the Corporation’s common stock on a one-to-one basis. Compensation expense related to restricted stock units is recognized over the expected requisite performance or service period, as applicable. A summary of the activity for restricted stock units as of and for the six months ended June 30, 2017 is presented below: Number of Units Weighted-average grant date fair value per unit Outstanding at December 31, 2016 298,357 $ 32.81 Granted 162,771 52.10 Converted into shares of common stock (40,141 ) 26.86 Forfeited/expired (3,529 ) 47.27 Outstanding at June 30, 2017 417,458 $ 40.79 At June 30, 2017 , unrecognized compensation expense related to restricted stock units totaled $11.5 million and is expected to be recognized over a remaining weighted average period of 3.2 years . Restricted Stock Awards The Corporation assumed restricted stock awards in the merger with Talmer that vest upon completion of future 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. If an individual awarded restricted stock awards terminates employment prior to the end of the vesting period, the unvested portion of the stock is forfeited, with certain exceptions. The following table provides information regarding nonvested restricted stock awards: Nonvested restricted stock awards Number of Awards Weighted-average acquisition-date Nonvested at January 1, 2017 365,891 $ 46.23 Vested (61,049 ) 46.23 Forfeited (3,657 ) 46.23 Nonvested at June 30, 2017 301,185 $ 46.23 At June 30, 2017 , unrecognized compensation expense related to nonvested restricted stock awards totaled $2.7 million and is expected to be recognized over a remaining weighted average period of 1.0 years.

Pension and Other Postretiremen

Pension and Other Postretirement Benefit Plans	6 Months Ended
	Jun. 30, 2017
Retirement Benefits [Abstract]
Pension and Other Postretirement Benefit Plans	Pension and Other Postretirement Benefit Plans The Corporation's retirement plans include a qualified pension plan, a nonqualified pension plan, a nonqualified postretirement benefit plan, a 401(k) savings plan, and a multi-employer defined benefit plan. Qualified and Nonqualified Pension Plans and Nonqualified Postretirement Benefit Plans 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) 2017 2016 2017 2016 Defined Benefit Pension Plans Service cost $ 234 $ 277 $ 467 $ 554 Interest cost 1,301 1,358 2,603 2,716 Expected return on plan assets (2,217 ) (2,140 ) (4,434 ) (4,281 ) Amortization of unrecognized net loss 579 572 1,157 1,144 Net periodic benefit cost (income) $ (103 ) $ 67 $ (207 ) $ 133 Postretirement Benefit Plan Service cost $ 1 $ 2 $ 2 $ 4 Interest cost 23 33 47 66 Amortization of prior service cost — 29 — 58 Amortization of unrecognized net gain (40 ) (25 ) (81 ) (49 ) Net periodic benefit cost (income) $ (16 ) $ 39 $ (32 ) $ 79 The Corporation did no t make a contribution to the pension plan during the three and six months ended June 30, 2017 or 2016 . The discount rates used to compute the Corporation's qualified and nonqualified pension plan expense are 4.22% and 3.63% , respectively, for 2017 . The discount rate used to compute the Corporation's nonqualified postretirement benefit plan for 2017 is 3.79% . 401(k) Savings Plan 401(k) Savings Plan expense for the Corporation’s match of participants’ base compensation contributions and a 4.0% of eligible pay contribution to employees who are not grandfathered under the pension plan was $2.4 million and $1.4 million for the three months ended June 30, 2017 and 2016 , respectively, and $5.0 million and $2.7 million for the six months ended June 30, 2017 and 2016 , respectively. The Corporation's base compensation match equals 50.0% of the participants' elective deferrals on the first 4.0% of the participants' base compensation up to the maximum amount allowed under the Internal Revenue Code. Multi-Employer Defined Benefit Plan In conjunction with the April 1, 2015 acquisition of Monarch, the Corporation acquired a participation in the Pentegra Defined Benefit Plan for Financial Institutions (Pentegra DB Plan), a qualified defined benefit pension plan. Employee benefits for Monarch employees under the Plan were frozen effective April 1, 2004. The Pentegra DB Plan operates as a multi-employer plan for accounting purposes and as a multiple-employer plan under the Employee Retirement Income Security Act of 1974 and the Internal Revenue Code (IRC). The Pentegra DB Plan is a single plan under IRC Section 413(c) and, as a result, all of the plan's assets stand behind all of the plan's liabilities. Accordingly, contributions made by a participating employer may be used to provide benefits to participants of other participating employers. No contributions were made by the Corporation to the Pentegra DB Plan for the three and six months ended June 30, 2017 and 2016 .

Regulatory Capital

Regulatory Capital	6 Months Ended
	Jun. 30, 2017
Banking and Thrift [Abstract]
Regulatory Capital	Regulatory Capital 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, 2017 , substantially all of the assets of Chemical Bank were restricted from transfer to the Corporation in the form of loans or advances. Dividends from the 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 the 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 Corporation’s consolidated financial statements. Management believes as of June 30, 2017 , 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 of the Corporation and Chemical Bank totaled $14.35 billion and $14.30 billion at June 30, 2017 , respectively, compared to $13.42 billion and $13.36 billion at December 31, 2016 , respectively. Effective January 1, 2015, the Corporation adopted the Basel III regulatory capital framework as approved by federal banking agencies, which is 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 is phased-in over a four-year period beginning January 1, 2016. The capital conservation buffer for 2017 is 1.25% and was 0.625% for 2016. The Corporation has elected to opt-out of including accumulated other comprehensive income in common equity tier 1 capital. At June 30, 2017 and December 31, 2016 , 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 Minimum Required for Capital Adequacy Purposes Plus 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 Capital Amount Ratio June 30, 2017 Total Capital to Risk-Weighted Assets Corporation $ 1,598,217 11.1 % $ 1,147,806 8.0 % $ 1,327,151 9.3 % N/A N/A Chemical Bank 1,608,525 11.2 1,144,292 8.0 1,323,088 9.3 $ 1,430,365 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,492,038 10.4 860,855 6.0 1,040,199 7.3 N/A N/A Chemical Bank 1,517,972 10.6 858,219 6.0 1,037,015 7.3 1,144,292 8.0 Common Equity Tier 1 Capital to Risk-Weighted Assets Corporation 1,492,038 10.4 645,641 4.5 824,986 5.8 N/A N/A Chemical Bank 1,517,972 10.6 643,664 4.5 822,460 5.8 929,737 6.5 Leverage Ratio Corporation 1,492,038 8.7 683,677 4.0 683,677 4.0 N/A N/A Chemical Bank 1,517,972 8.9 682,224 4.0 682,224 4.0 852,780 5.0 December 31, 2016 Total Capital to Risk-Weighted Assets Corporation $ 1,543,018 11.5 % $ 1,073,431 8.0 % $ 1,157,293 8.6 % N/A N/A Chemical Bank 1,608,980 12.0 1,068,560 8.0 1,152,041 8.6 $ 1,335,700 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,441,209 10.7 805,073 6.0 888,935 6.6 N/A N/A Chemical Bank 1,522,711 11.4 801,420 6.0 884,901 6.6 1,068,560 8.0 Common Equity Tier 1 Capital to Risk-Weighted Asset Corporation 1,441,209 10.7 603,805 4.5 687,667 5.1 N/A N/A Chemical Bank 1,522,711 11.4 601,065 4.5 684,546 5.1 868,205 6.5 Leverage Ratio Corporation 1,441,209 9.0 643,603 4.0 643,603 4.0 N/A N/A Chemical Bank 1,522,711 9.5 641,457 4.0 641,457 4.0 801,822 5.0 On July 19, 2017, a cash dividend on the Corporation's common stock of $0.28 per share was declared. The dividend will be paid on September 15, 2017 to shareholders of record as of September 1, 2017.

Earnings Per Common Share

Earnings Per Common Share	6 Months Ended
	Jun. 30, 2017
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) 2017 2016 2017 2016 Net income $ 52,014 $ 25,775 $ 99,618 $ 49,380 Net income allocated to participating securities 219 — 446 — Net income allocated to common shareholders (1) $ 51,795 $ 25,775 $ 99,172 $ 49,380 Weighted average common shares - issued 71,122 38,258 71,046 38,228 Average unvested restricted share awards (303 ) — (321 ) — Weighted average common shares outstanding - basic 70,819 38,258 70,725 38,228 Effect of dilutive securities Weighted average common stock equivalents 624 342 704 332 Weighted average common shares outstanding - diluted 71,443 38,600 71,429 38,560 EPS available to common shareholders Basic earnings per common share $ 0.73 $ 0.67 $ 1.41 $ 1.29 Diluted earnings per common share $ 0.73 $ 0.67 $ 1.39 $ 1.28 (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 and warrants 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 effect of dilutive securities, the assumed average stock valuation is $47.78 per share and $37.80 per share for the three months ended June 30, 2017 and 2016 , respectively and $49.78 and $35.55 for the six months ended June 30, 2017 and 2016 , respectively. The average number of exercisable employee stock options 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 125,782 and 90,537 for the three and six months ended June 30, 2017 and zero for both the three and six months ended June 30, 2016 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2017
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, 2017 , and 2016 : (Dollars in thousands) Unrealized gains Defined Benefit Pension Plans Unrealized gains (losses) on cash flow hedges, net of tax Total For the three months ended June 30, 2017 Beginning balance $ (12,420 ) $ (25,545 ) $ — $ (37,965 ) Other comprehensive income before reclassifications 3,593 — (466 ) 3,127 Amounts reclassified from accumulated other comprehensive income (50 ) 350 409 709 Net current period other comprehensive income 3,543 350 (57 ) 3,836 Ending balance $ (8,877 ) $ (25,195 ) $ (57 ) $ (34,129 ) For the three months ended June 30, 2016 Beginning balance $ 829 $ (27,519 ) $ — $ (26,690 ) Other comprehensive income before reclassifications 1,379 — — 1,379 Amounts reclassified from accumulated other comprehensive income (12 ) (375 ) — (387 ) Net current period other comprehensive income (loss) 1,367 (375 ) — 992 Ending balance $ 2,196 $ (27,894 ) $ — $ (25,698 ) For the six months ended June 30, 2017 Beginning balance $ (14,142 ) $ (25,894 ) $ — $ (40,036 ) Other comprehensive income (loss) before reclassifications 5,374 — (466 ) 4,908 Amounts reclassified from accumulated other comprehensive income (109 ) 699 409 999 Net current period other comprehensive income (loss) 5,265 699 (57 ) 5,907 Ending balance $ (8,877 ) $ (25,195 ) $ (57 ) $ (34,129 ) For the six months ended June 30, 2016 Beginning balance $ (1,888 ) $ (27,144 ) $ — $ (29,032 ) Other comprehensive income before reclassifications 4,108 — — 4,108 Amounts reclassified from accumulated other comprehensive income (24 ) (750 ) — (774 ) Net current period other comprehensive income 4,084 (750 ) — 3,334 Ending balance $ 2,196 $ (27,894 ) $ — $ (25,698 ) 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, 2017 , and 2016 : (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, 2017 2016 2017 2016 Gains and losses on available-for-sale securities $ 77 $ 18 $ 167 $ 37 Gain on sale of investment securities (noninterest income) (27 ) (6 ) (58 ) (13 ) Income tax (expense)/benefit $ 50 $ 12 $ 109 $ 24 Net Income Amortization of defined benefit pension plan items $ (539 ) $ 577 $ (1,076 ) $ 1,154 Salaries, wages and employee benefits (operating expenses) 189 (202 ) 377 (404 ) Income tax (expense)/benefit $ (350 ) $ 375 (699 ) $ 750 Net Income (loss) Gains and losses on cash flow hedges $ 409 $ — $ 409 $ — Interest on short-term borrowings (interest expense) $ (409 ) $ — $ (409 ) $ — Net Income (loss)

Basis of Presentation and Sig28

Basis of Presentation and Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2017
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 Midland, Michigan, that operates through one commercial bank, Chemical Bank. Chemical Bank operates within Michigan, Ohio and Indiana as a Michigan state-chartered commercial bank. Chemical Bank operates through an internal organizational structure of seven regional banking units and offers a full range of traditional banking and fiduciary products and services to the residents and business customers in the bank’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 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, 2016. 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. Operating results for the six months ended June 30, 2017 are not necessarily indicative of the results that may be expected for the year ending December 31, 2017 .
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, fair value amounts related to business combinations, income taxes, goodwill impairment and those assets and liabilities that require fair value measurement. 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 with the current presentation. The reclassification had no effect on net income or shareholders’ equity as previously reported.
Loan Servicing Rights	Loan Servicing Rights Effective January 1, 2017, the Corporation elected to account for all loan servicing rights ("LSRs") previously accounted for under the lower of cost or fair value method under the fair value method. The guidance in Accounting Standards Codification Subtopic 860-50, "Transfers and Servicing-Servicing Assets and Liabilities" provides that an entity may make an irrevocable decision to subsequently measure a class of servicing assets and servicing liabilities at fair value at the beginning of any fiscal year. The guidance allows for the Corporation to apply this election prospectively to all new and existing servicing assets and servicing liabilities. Management believes this election will provide more comparable results to peers as many of those within our industry group account for loan servicing rights under the fair value method. The change in accounting policy in the first quarter of 2017 results in a cumulative adjustment to increase retained earnings in the amount of $3.7 million , net of taxes.
Investment Securities	Investment Securities The Corporation has elected to early adopt Accounting Standards Update ("ASU") No. 2017-08, Receivables-Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities ("ASU 2017-08") during the second quarter of 2017. The guidance in ASU 2017-08 shortens the amortization period for certain callable debt securities that are held at a premium to the earliest call date. Debt securities held at a discount will continue to be amortized as a yield adjustment over the life of the instrument. The early adoption of ASU 2017-08 in the second quarter of 2017 did not have a material impact on the consolidated financial statements.

Mergers and Acquisitions (Table

Mergers and Acquisitions (Tables)	6 Months Ended
	Jun. 30, 2017
Business Combinations [Abstract]
Summary of assets acquired and liabilities assumed	The following allocation is based on the information that was available to make preliminary estimates of the fair value and may change as additional information becomes available and additional analyses are completed. While the Corporation believes that information provided a reasonable basis for estimating the fair values, it expects that it could obtain additional information and evidence during the measurement period that may result in changes to the estimated fair value amounts. This measurement period ends on the earlier of one year after the merger date or the date we receive the information about the facts and circumstances that existed at the merger date. Subsequent adjustments, if necessary, will be reflected in future filings. These refinements include: (1) changes in the estimated fair value of loans acquired: (2) changes in the estimated fair value of intangible assets acquired: (3) changes in deferred tax assets related to fair value estimates and a change in the expected realization of items considered to be net operating loss carry forwards and (4) a change in the goodwill caused by the net effect of these adjustments. The following table presents the allocation of fair value at the merger date: (Dollars in thousands) Consideration paid: Stock $ 1,504,811 Cash 107,638 Total consideration 1,612,449 Fair value of identifiable assets acquired: Cash and cash equivalents 433,352 Investment securities: Available-for-sale 808,894 Held-to-maturity 1,657 Loans held-for-sale 244,916 Loans 4,882,402 Premises and equipment 38,793 Loan servicing rights 42,462 Other intangible assets 19,088 Interest receivable and other assets 395,119 Total identifiable assets acquired $ 6,866,683 Fair value of liabilities assumed: Noninterest-bearing deposits 1,236,902 Interest-bearing deposits 4,057,716 Interest payable and other liabilities 99,482 Securities sold under agreements to repurchase with customers 19,704 Short-term borrowings 387,500 Long-term borrowings 299,597 Total liabilities assumed $ 6,100,901 Fair value of net identifiable assets acquired $ 765,782 Goodwill resulting from acquisition $ 846,667
Information regarding acquired loans accounted for under ASC 310-30	Information regarding loans accounted for under ASC 310-30 at the merger date is as follows: (Dollars in thousands) Accounted for under ASC 310-30: Contractual cash flows $ 5,968,488 Contractual cash flows not expected to be collected (nonaccretable difference) 223,959 Expected cash flows 5,744,529 Interest component of expected cash flows (accretable yield) 862,127 Fair value at acquisition $ 4,882,402
Pro forma financial information	The following unaudited pro forma financial information presents the consolidated results of operation of the Corporation and Talmer as if the merger had occurred as of January 1, 2016. The unaudited pro forma combined results of operations are presented solely for information purposes and are not intended to represent or be indicative of the consolidated results of operations that Chemical would have reported had these transactions been completed as of the dates and for the periods presented, nor are they necessarily indicative of future results. In particular, no adjustments have been made to eliminate the amount of Talmer's provision for loan losses incurred prior to the acquisition date that would not have been necessary had the acquired loans been recorded at fair value as of the beginning of each period indicated. In accordance with Article 11 of SEC Regulation S-X, transaction costs directly attributable to the acquisitions have been excluded. Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) (1) 2017 2016 2017 2016 Net interest and other income $ 179,516 $ 168,130 $ 347,623 $ 326,100 Net Income 52,014 42,111 99,618 81,163 Earnings per share: Basic $ 0.73 $ 0.60 $ 1.41 $ 1.15 Diluted 0.73 0.59 1.39 1.14 (1) As the business combination was effective August 31, 2016, there were no proforma adjustments for the three and six months ended June 30, 2017 .

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2017
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 (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Total June 30, 2017 Investment securities – available-for-sale: U.S. Treasury securities $ 5,793 $ — $ — $ 5,793 Government sponsored agencies — 247,474 — 247,474 State and political subdivisions — 292,035 — 292,035 Residential mortgage-backed securities — 292,912 — 292,912 Collateralized mortgage obligations — 733,187 — 733,187 Corporate bonds — 158,168 — 158,168 Preferred stock and trust preferred securities — 37,909 — 37,909 Total investment securities – available-for-sale 5,793 1,761,685 — 1,767,478 Loans held-for-sale — 65,371 — 65,371 Loan servicing rights — — 64,522 64,522 Derivative assets: Customer-initiated derivatives — 8,636 — 8,636 Forward contracts related to mortgage loans to be delivered for sale — 617 — 617 Interest rate lock commitments — 1,997 — 1,997 Power Equity CD — 2,062 — 2,062 Risk management derivatives — 224 — 224 Total derivatives — 13,536 — 13,536 Total assets at fair value $ 5,793 $ 1,840,592 $ 64,522 $ 1,910,907 Derivative liabilities: Customer-initiated derivatives — 9,152 — 9,152 Power Equity CD — 2,062 — 2,062 Risk management derivatives — 282 — 282 Total derivatives — 11,496 — 11,496 Total liabilities at fair value $ — $ 11,496 $ — $ 11,496 December 31, 2016 Investment securities – available-for-sale: U.S. Treasury securities $ 5,793 $ — $ — $ 5,793 Government sponsored agencies — 215,011 — 215,011 State and political subdivisions — 300,088 — 300,088 Residential mortgage-backed securities — 272,282 — 272,282 Collateralized mortgage obligations — 320,025 — 320,025 Corporate bonds — 89,474 — 89,474 Preferred stock and trust preferred securities — 32,291 — 32,291 Total investment securities – available-for-sale 5,793 1,229,171 — 1,234,964 Loans held-for-sale — 81,830 — 81,830 Loan servicing rights — — 48,085 48,085 Derivative assets: Customer-initiated derivatives — 4,406 — 4,406 Forward contracts related to mortgage loans to be delivered for sale — 635 — 635 Interest rate lock commitments — 956 — 956 Power Equity CD — 2,218 — 2,218 Total derivatives — 8,215 — 8,215 Total assets at fair value $ 5,793 $ 1,319,216 $ 48,085 $ 1,373,094 Derivative liabilities: Customer-initiated derivatives — 4,141 — 4,141 Power Equity CD — 2,218 — 2,218 Total derivatives — 6,359 — 6,359 Total liabilities at fair value $ — $ 6,359 $ — $ 6,359
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, 2017 Six Months Ended June 30, 2017 (Dollars in thousands) Loan servicing rights Balance, beginning of period $ 64,604 $ 48,085 Transfer in based on new accounting policy election (1) — 15,891 Gains (losses): Recorded in earnings (realized): Recorded in "Net gain on sale of loans and other mortgage banking revenue" (2,466 ) (3,591 ) New originations 2,384 4,137 Balance, end of period $ 64,522 $ 64,522 (1) Refer to Note 1, Basis of Presentation and Significant Accounting Policies, for further details.
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, 2017 December 31, 2016 Aggregate fair value $ 65,371 $ 81,830 Contractual balance 63,162 81,009 Unrealized gain (loss) 2,209 821
Amount of gains (losses) from loans held for sale included in the Consolidated Statements of Income	The total amount of gains (losses) from loans held-for-sale included in the Consolidated Statements of Income were as follows: Three Months Ended June 30, Six Months Ended June 30, (Dollars in thousands) 2017 2016 2017 2016 Interest income (1) $ 463 $ 20 $ 1,014 $ 39 Change in fair value (2) 787 — 1,388 — Net gain on sales of loans (2) 13,905 2,135 20,025 3,431 Total included in earnings $ 15,155 $ 2,155 $ 22,427 $ 3,470 (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.
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 follows: (Dollars in thousands) Significant Unobservable Inputs (Level 3) Total June 30, 2017 Impaired originated loans $ 63,694 $ 63,694 Other real estate/repossessed assets 3,811 3,811 Total $ 67,505 $ 67,505 December 31, 2016 Impaired originated loans $ 62,184 $ 62,184 Other real estate/repossessed assets 1,386 1,386 Loan servicing rights 2 2 Total $ 63,572 $ 63,572
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 June 30, 2017 Valuation Technique Significant Unobservable Inputs Range Impaired originated loans $ 63,694 Appraisal of collateral Discount for type of collateral and age of appraisal 10%-25% Other real estate/repossessed assets 3,811 Appraisal of property Discount for type of property and age of appraisal 10%-25%
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 was as follows: Level in Fair Value Measurement Hierarchy June 30, 2017 December 31, 2016 (Dollars in thousands) Carrying Amount Fair Value Carrying Amount Fair Value Financial assets: Cash and cash equivalents Level 1 $ 619,241 $ 619,241 $ 474,402 $ 474,402 Investment securities: Held-to-maturity Level 2 645,105 639,683 622,927 608,221 Held-to-maturity Level 3 500 360 500 310 Nonmarketable equity securities Level 2 180,196 180,196 97,350 97,350 Net loans (1) Level 3 13,583,575 13,758,368 12,912,511 13,069,315 Interest receivable Level 2 45,832 45,832 42,235 42,235 Bank-owned life insurance Level 2 145,671 145,671 143,718 143,718 Financial liabilities: Deposits: Deposits without defined maturities Level 2 $ 10,217,235 $ 10,217,235 $ 9,862,755 $ 9,862,755 Time deposits Level 2 2,987,132 2,987,779 3,010,367 3,010,048 Total deposits 13,204,367 13,205,014 12,873,122 12,872,803 Interest payable Level 2 5,112 5,112 5,415 5,415 Securities sold under agreements to repurchase with customers Level 2 310,042 310,042 343,047 343,047 Short-term borrowings Level 2 2,050,000 2,048,744 825,000 825,000 Long-term borrowings Level 2 435,852 431,345 597,847 591,227 (1) Included $63.7 million and $62.2 million of impaired loans recorded at fair value on a nonrecurring basis at June 30, 2017 and December 31, 2016 , respectively.

Investment Securities (Tables)

Investment Securities (Tables)	6 Months Ended
	Jun. 30, 2017
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 available-for-sale and investment securities held-to-maturity at June 30, 2017 and December 31, 2016 : Investment Securities Available-for-Sale (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2017 U.S. Treasury securities $ 5,795 $ — $ 2 $ 5,793 Government sponsored agencies 248,021 619 1,166 247,474 State and political subdivisions 297,560 114 5,639 292,035 Residential mortgage-backed securities 296,898 26 4,012 292,912 Collateralized mortgage obligations 737,963 173 4,949 733,187 Corporate bonds 158,828 276 936 158,168 Preferred stock and trust preferred securities 36,070 1,871 32 37,909 Total $ 1,781,135 $ 3,079 $ 16,736 $ 1,767,478 December 31, 2016 U.S. Treasury securities $ 5,788 $ 5 $ — $ 5,793 Government sponsored agencies 216,890 189 2,068 215,011 State and political subdivisions 311,704 163 11,779 300,088 Residential mortgage-backed securities 276,162 112 3,992 272,282 Collateralized mortgage obligations 323,965 63 4,003 320,025 Corporate bonds 90,859 16 1,401 89,474 Preferred stock and trust preferred securities 31,353 1,018 80 32,291 Total $ 1,256,721 $ 1,566 $ 23,323 $ 1,234,964
Held-to-maturity Securities	Investment Securities Held-to-Maturity (Dollars in thousands) Amortized Cost Unrealized Gains Unrealized Losses Fair Value June 30, 2017 State and political subdivisions $ 645,105 $ 5,281 $ 10,703 $ 639,683 Trust preferred securities 500 — 140 360 Total $ 645,605 $ 5,281 $ 10,843 $ 640,043 December 31, 2016 State and political subdivisions $ 622,927 $ 2,648 $ 17,354 $ 608,221 Trust preferred securities 500 — 190 310 Total $ 623,427 $ 2,648 $ 17,544 $ 608,531
Proceeds from sales of securities and the associated gains and losses recorded in earnings	Proceeds from sales of securities 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) 2017 2016 2017 2016 Proceeds $ 10,050 $ 4,356 $ 10,050 $ 5,000 Gross gains 77 18 167 37
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, 2017 , by maturity, for both available-for-sale and held-to-maturity investment securities. 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, 2017 (Dollars in thousands) Amortized Cost Fair Value Investment Securities Available-for-Sale: Due in one year or less $ 345,833 $ 344,064 Due after one year through five years 731,523 726,231 Due after five years through ten years 488,832 485,107 Due after ten years 213,558 210,229 Preferred stock 1,389 1,847 Total $ 1,781,135 $ 1,767,478 Investment Securities Held-to-Maturity: Due in one year or less $ 85,434 $ 85,398 Due after one year through five years 253,002 251,488 Due after five years through ten years 143,396 141,140 Due after ten years 163,773 162,017 Total $ 645,605 $ 640,043
Summary of continuous unrealized loss position of securities	The following schedule summarizes information for both available-for-sale and held-to-maturity investment securities with gross unrealized losses at June 30, 2017 and December 31, 2016 , aggregated by category and length of time that individual securities have been in a continuous unrealized loss position. As of June 30, 2017 , the Corporation’s securities portfolio consisted of 2,336 securities, 1,351 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, 2017 U.S. Treasury securities $ 5,793 $ 2 $ — $ — $ 5,793 $ 2 Government sponsored agencies 104,655 1,042 10,816 124 115,471 1,166 State and political subdivisions 614,276 15,504 46,588 838 660,864 16,342 Residential mortgage-backed securities 284,277 4,012 — — 284,277 4,012 Collateralized mortgage obligations 627,054 4,765 11,061 184 638,115 4,949 Corporate bonds 111,931 935 1,499 1 113,430 936 Trust preferred securities 3,843 32 360 140 4,203 172 Total $ 1,751,829 $ 26,292 $ 70,324 $ 1,287 $ 1,822,153 $ 27,579 December 31, 2016 Government sponsored agencies $ 105,702 $ 1,707 $ 15,023 $ 361 $ 120,725 $ 2,068 State and political subdivisions 758,063 28,158 26,810 975 784,873 29,133 Residential mortgage-backed securities 244,239 3,992 — — 244,239 3,992 Collateralized mortgage obligations 279,001 3,778 14,754 225 293,755 4,003 Corporate bonds 80,536 1,401 — — 80,536 1,401 Trust preferred securities 10,699 80 310 190 11,009 270 Total $ 1,478,240 $ 39,116 $ 56,897 $ 1,751 $ 1,535,137 $ 40,867

Loans (Tables)

Loans (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 Commercial loan portfolio: Commercial $ 2,184,283 $ 1,175,878 $ 3,360,161 Commercial real estate 2,405,772 1,918,551 4,324,323 Real estate construction and land development 349,395 97,283 446,678 Subtotal 4,939,450 3,191,712 8,131,162 Consumer loan portfolio: Residential mortgage 1,683,550 1,441,847 3,125,397 Consumer installment 1,429,088 124,879 1,553,967 Home equity 607,534 249,312 856,846 Subtotal 3,720,172 1,816,038 5,536,210 Total loans $ 8,659,622 $ 5,007,750 $ 13,667,372 (2) December 31, 2016 Commercial loan portfolio: Commercial $ 1,901,526 $ 1,315,774 $ 3,217,300 Commercial real estate 1,921,799 2,051,341 3,973,140 Real estate construction and land development 281,724 122,048 403,772 Subtotal 4,105,049 3,489,163 7,594,212 Consumer loan portfolio: Residential mortgage 1,475,342 1,611,132 3,086,474 Consumer installment 1,282,588 151,296 1,433,884 Home equity 595,422 280,787 876,209 Subtotal 3,353,352 2,043,215 5,396,567 Total loans $ 7,458,401 $ 5,532,378 $ 12,990,779 (2) (1) Acquired loans are accounted for under ASC 310-30. (2) Reported net of deferred costs totaling $20.0 million and $14.8 million at June 30, 2017 and December 31, 2016 , respectively.
Schedule of activity for accretable yield	Activity for the accretable yield, which includes contractually due interest 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, 2017 Balance at beginning of period $ 774,778 $ 113,211 $ 26,055 $ 64,897 $ 21,467 $ 1,000,408 Accretion recognized in interest income (45,091 ) (7,583 ) (1,159 ) (5,467 ) (3,314 ) (62,614 ) Net reclassification (to) from nonaccretable difference (1) 71,682 15,944 (626 ) 11,782 1,643 100,425 Balance at end of period $ 801,369 $ 121,572 $ 24,270 $ 71,212 $ 19,796 $ 1,038,219 Three Months Ended June 30, 2016 Balance at beginning of period $ — $ 137,975 $ 33,235 $ 76,368 $ 27,036 $ 274,614 Accretion recognized in interest income — (8,338 ) (1,385 ) (4,028 ) (3,727 ) (17,478 ) Net reclassification (to) from nonaccretable difference (1) — (4,294 ) (991 ) 1,406 3,283 (596 ) Balance at end of period $ — $ 125,343 $ 30,859 $ 73,746 $ 26,592 $ 256,540 Six Months Ended June 30, 2017 Balance at beginning of period $ 798,210 $ 121,416 $ 27,182 $ 69,847 $ 23,316 $ 1,039,971 Accretion recognized in interest income (89,662 ) (14,849 ) (2,340 ) (9,359 ) (6,591 ) (122,801 ) Net reclassification (to) from nonaccretable difference (1) 92,821 15,005 (572 ) 10,724 3,071 121,049 Balance at end of period $ 801,369 $ 121,572 $ 24,270 $ 71,212 $ 19,796 $ 1,038,219 Six Months Ended June 30, 2016 Balance at beginning of period $ — $ 152,999 $ 34,558 $ 82,623 $ 28,077 $ 298,257 Accretion recognized in interest income — (17,291 ) (2,836 ) (8,029 ) (6,284 ) (34,440 ) Net reclassification (to) from nonaccretable difference (1) — (10,365 ) (863 ) (848 ) 4,799 (7,277 ) Balance at end of period $ — $ 125,343 $ 30,859 $ 73,746 $ 26,592 $ 256,540 (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, 2017 and December 31, 2016 : (Dollars in thousands) Pass Special Mention Substandard Doubtful Total June 30, 2017 Originated Portfolio: Commercial $ 2,101,781 $ 31,051 $ 47,871 $ 3,580 $ 2,184,283 Commercial real estate 2,341,493 29,840 33,390 1,049 2,405,772 Real estate construction and land development 349,339 — 56 — 349,395 Subtotal 4,792,613 60,891 81,317 4,629 4,939,450 Acquired Portfolio: Commercial 1,100,238 30,686 44,951 3 1,175,878 Commercial real estate 1,777,461 62,807 78,118 165 1,918,551 Real estate construction and land development 93,301 1,941 2,041 — 97,283 Subtotal 2,971,000 95,434 125,110 168 3,191,712 Total $ 7,763,613 $ 156,325 $ 206,427 $ 4,797 $ 8,131,162 December 31, 2016 Originated Portfolio: Commercial $ 1,803,750 $ 44,809 $ 51,898 $ 1,069 $ 1,901,526 Commercial real estate 1,849,315 36,981 35,502 1 1,921,799 Real estate construction and land development 280,968 157 599 — 281,724 Subtotal 3,934,033 81,947 87,999 1,070 4,105,049 Acquired Portfolio: Commercial 1,218,848 46,643 50,283 — 1,315,774 Commercial real estate 1,897,011 61,441 92,636 253 2,051,341 Real estate construction and land development 117,505 1,982 2,561 — 122,048 Subtotal 3,233,364 110,066 145,480 253 3,489,163 Total $ 7,167,397 $ 192,013 $ 233,479 $ 1,323 $ 7,594,212
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, 2017 and December 31, 2016 : (Dollars in thousands) Residential Mortgage Consumer Installment Home Equity Total Consumer June 30, 2017 Originated Loans: Performing $ 1,675,836 $ 1,428,331 $ 603,663 $ 3,707,830 Nonperforming 7,714 757 3,871 12,342 Subtotal 1,683,550 1,429,088 607,534 3,720,172 Acquired Loans 1,441,847 124,879 249,312 1,816,038 Total $ 3,125,397 $ 1,553,967 $ 856,846 $ 5,536,210 December 31, 2016 Originated Loans: Performing $ 1,468,373 $ 1,281,709 $ 592,071 $ 3,342,153 Nonperforming 6,969 879 3,351 11,199 Subtotal 1,475,342 1,282,588 595,422 3,353,352 Acquired Loans 1,611,132 151,296 280,787 2,043,215 Total $ 3,086,474 $ 1,433,884 $ 876,209 $ 5,396,567
Summary of nonperforming loans	A summary of nonperforming loans follows: (Dollars in thousands) June 30, December 31, Nonperforming assets Nonaccrual loans: Commercial $ 18,773 $ 13,178 Commercial real estate 19,723 19,877 Real estate construction and land development 56 80 Residential mortgage 7,714 6,969 Consumer installment 757 879 Home equity 3,871 3,351 Total nonaccrual loans 50,894 44,334 Other real estate owned and repossessed assets 14,582 17,187 Total nonperforming assets $ 65,476 $ 61,521 Accruing loans contractually past due 90 days or more as to interest or principal payments, excluding acquired loans accounted for under ASC 310-30 Commercial 58 11 Commercial real estate 262 277 Home equity 2,026 995 Total accruing loans contractually past due 90 days or more as to interest or principal payments, excluding acquired loans accounted for under ASC 310-30 $ 2,346 $ 1,283
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: (Dollars in thousands) 30-59 days past due 60-89 days past due 90 days or more past due Total past due Current Total loans 90 days or more past due and still accruing June 30, 2017 Originated Portfolio: Commercial $ 6,578 $ 5,408 $ 7,604 $ 19,590 $ 2,164,693 $ 2,184,283 $ 58 Commercial real estate 21,106 7,518 5,221 33,845 2,371,927 2,405,772 262 Real estate construction and land development — — — — 349,395 349,395 — Residential mortgage 411 2,607 1,418 4,436 1,679,114 1,683,550 — Consumer installment 2,553 363 156 3,072 1,426,016 1,429,088 — Home equity 3,798 1,095 2,775 7,668 599,866 607,534 2,026 Total $ 34,446 $ 16,991 $ 17,174 $ 68,611 $ 8,591,011 $ 8,659,622 $ 2,346 December 31, 2016 Originated Portfolio: Commercial $ 10,421 $ 4,842 $ 3,641 $ 18,904 $ 1,882,622 $ 1,901,526 $ 11 Commercial real estate 6,551 1,589 5,165 13,305 1,908,494 1,921,799 277 Real estate construction and land development 2,721 499 — 3,220 278,504 281,724 — Residential mortgage 3,147 62 1,752 4,961 1,470,381 1,475,342 — Consumer installment 3,991 675 238 4,904 1,277,684 1,282,588 — Home equity 3,097 893 2,349 6,339 589,083 595,422 995 Total $ 29,928 $ 8,560 $ 13,145 $ 51,633 $ 7,406,768 $ 7,458,401 $ 1,283
Schedule of Impaired loans by classes	The following schedules present impaired loans by classes of loans at June 30, 2017 and December 31, 2016 : (Dollars in thousands) Recorded Investment Unpaid Principal Balance Related Valuation Allowance June 30, 2017 Impaired loans with a valuation allowance: Commercial $ 28,623 $ 31,419 $ 4,335 Commercial real estate 20,209 25,552 1,334 Real estate construction and land development 189 189 4 Residential mortgage 16,711 16,711 724 Consumer installment 851 851 88 Home equity 4,658 4,658 1,062 Subtotal 71,241 79,380 7,547 Impaired loans with no related valuation allowance: Commercial 7,677 9,761 — Commercial real estate 21,512 25,411 — Real estate construction and land development 56 56 — Residential mortgage 4,386 4,386 — Home equity 1,258 1,258 — Subtotal 34,889 40,872 — Total impaired loans: Commercial 36,300 41,180 4,335 Commercial real estate 41,721 50,963 1,334 Real estate construction and land development 245 245 4 Residential mortgage 21,097 21,097 724 Consumer installment 851 851 88 Home equity 5,916 5,916 1,062 Total $ 106,130 $ 120,252 $ 7,547 December 31, 2016 Impaired loans with a valuation allowance: Commercial $ 28,925 $ 33,209 $ 3,128 Commercial real estate 21,318 27,558 2,102 Real estate construction and land development 177 177 4 Residential mortgage 20,864 20,864 3,528 Consumer installment 879 879 240 Home equity 2,577 2,577 390 Subtotal 74,740 85,264 9,392 Impaired loans with no related valuation allowance: Commercial 7,435 11,153 — Commercial real estate 20,588 23,535 — Real estate construction and land development 80 80 — Residential mortgage 3,252 3,252 — Home equity 774 774 — Subtotal 32,129 38,794 — Total impaired loans: Commercial 36,360 44,362 3,128 Commercial real estate 41,906 51,093 2,102 Real estate construction and land development 257 257 4 Residential mortgage 24,116 24,116 3,528 Consumer installment 879 879 240 Home equity 3,351 3,351 390 Total $ 106,869 $ 124,058 $ 9,392
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, 2017 and 2016 , and the respective interest income amounts recognized: Three Months Ended June 30, 2017 Three Months Ended June 30, 2016 Six Months Ended June 30, 2017 Six Months Ended June 30, 2016 (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 $ 24,493 $ 201 $ 3,867 $ — $ 25,103 $ 425 $ 7,209 $ — Commercial real estate 19,026 202 3,360 — 19,530 405 5,476 — Real estate construction and land development 141 3 — — 151 5 — — Residential mortgage 16,243 68 20,949 333 16,821 302 20,969 666 Consumer installment 682 1 — — 731 2 — — Home equity 4,024 16 — — 4,047 37 — — Subtotal $ 64,609 $ 491 $ 28,176 $ 333 $ 66,383 $ 1,176 $ 33,654 $ 666 Impaired loans with no related valuation allowance: Commercial $ 11,010 $ 48 $ 32,502 $ 310 $ 10,153 $ 78 $ 31,952 $ 587 Commercial real estate 25,183 99 45,679 312 24,329 203 45,708 692 Real estate construction and land development 106 — 860 2 93 — 889 8 Residential mortgage 4,581 10 5,094 — 4,194 17 5,121 — Consumer installment 142 — 281 — 179 — 311 — Home equity 1,162 5 1,984 — 1,021 6 2,186 — Subtotal $ 42,184 $ 162 $ 86,400 $ 624 $ 39,969 $ 304 $ 86,167 $ 1,287 Total impaired loans: Commercial $ 35,503 $ 249 $ 36,369 $ 310 $ 35,256 $ 503 $ 39,161 $ 587 Commercial real estate 44,209 301 49,039 312 43,859 608 51,184 692 Real estate construction and land development 247 3 860 2 244 5 889 8 Residential mortgage 20,824 78 26,043 333 21,015 319 26,090 666 Consumer installment 824 1 281 — 910 2 311 — Home equity 5,186 21 1,984 — 5,068 43 2,186 — Total $ 106,793 $ 653 $ 114,576 $ 957 $ 106,352 $ 1,480 $ 119,821 $ 1,953
Schedule providing information on TDRs	The following schedule presents the Corporation's TDRs at June 30, 2017 and December 31, 2016 : (Dollars in thousands) Accruing TDRs Nonaccrual TDRs Total June 30, 2017 Commercial loan portfolio $ 39,714 $ 21,296 $ 61,010 Consumer loan portfolio 15,522 4,409 19,931 Total $ 55,236 $ 25,705 $ 80,941 December 31, 2016 Commercial loan portfolio $ 45,388 $ 25,397 $ 70,785 Consumer loan portfolio 17,147 5,134 22,281 Total $ 62,535 $ 30,531 $ 93,066 The following tables present the recorded investment of loans modified into TDRs during the three and six months ended June 30, 2017 and 2016 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 Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2017 Commercial loan portfolio: Commercial $ 285 $ 266 $ — 7 $ 564 $ 551 Commercial real estate — 65 122 3 194 187 Subtotal 285 331 122 10 758 738 Consumer loan portfolio: Residential mortgage 37 261 — 5 316 298 Consumer installment 22 — — 4 24 22 Home equity 153 — — 4 160 153 Subtotal 212 261 — 13 500 473 Total loans $ 497 $ 592 $ 122 23 $ 1,258 $ 1,211 For the six months ended June 30, 2017 Commercial loan portfolio: Commercial $ 335 $ 1,367 $ 579 12 $ 2,303 $ 2,281 Commercial real estate 447 140 122 6 716 709 Subtotal 782 1,507 701 18 3,019 2,990 Consumer loan portfolio: Residential mortgage 135 261 — 6 414 396 Consumer installment 32 — — 6 35 32 Home equity 264 — — 5 325 264 Subtotal 431 261 — 17 774 692 Total loans $ 1,213 $ 1,768 $ 701 35 $ 3,793 $ 3,682 Concession type (Dollars in thousands) Principal Interest Forbearance Total Pre-modification recorded investment Post-modification recorded investment For the three months ended June 30, 2016 Commercial loan portfolio: Commercial $ 2,399 $ — $ 1,750 21 $ 4,149 $ 4,149 Commercial real estate 1,454 — — 2 1,454 1,454 Subtotal 3,853 — 1,750 23 5,603 5,603 Consumer loan portfolio: Residential mortgage 174 — — 2 174 174 Consumer installment 47 — — 8 47 47 Home equity 98 171 — 4 269 269 Subtotal 319 171 — 14 490 490 Total loans $ 4,172 $ 171 $ 1,750 37 $ 6,093 $ 6,093 For the six months ended June 30, 2016 Commercial loan portfolio: Commercial $ 6,231 $ — $ 1,750 28 $ 7,981 $ 7,981 Commercial real estate 2,441 — — 6 2,441 2,441 Subtotal 8,672 — 1,750 34 10,422 10,422 Consumer loan portfolio: Residential mortgage 279 — — 3 279 279 Consumer installment 80 — — 12 80 80 Home equity 127 208 — 6 335 335 Subtotal 486 208 — 21 694 694 Total loans $ 9,158 $ 208 $ 1,750 55 $ 11,116 $ 11,116
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, 2017 and 2016 , 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, 2017 For The Six Months Ended June 30, 2017 (Dollars in thousands) Number of loans Principal balance Number of loans Principal balance Commercial loan portfolio (commercial) 2 $ 997 5 $ 1,617 Consumer loan portfolio (residential mortgage) 3 58 5 163 Total 5 $ 1,055 10 $ 1,780 For The Three Months Ended June 30, 2016 For The Six Months Ended June 30, 2016 (Dollars in thousands) Number of loans Principal balance Number of loans Principal balance Commercial loan portfolio (commercial real estate) 1 $ 788 2 $ 1,721 Consumer loan portfolio (residential mortgage) 1 — 2 — Total 2 $ 788 4 $ 1,721
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 three and six months ended June 30, 2017 and 2016 , and details regarding the balance in the allowance and the recorded investment in loans at June 30, 2017 by impairment evaluation method. (Dollars in thousands) Commercial Loan Portfolio Consumer Loan Portfolio Total Changes in allowance for loan losses for the three months ended June 30, 2017: Beginning balance $ 54,315 $ 24,459 $ 78,774 Provision for loan losses 4,084 2,145 6,229 Charge-offs (726 ) (1,578 ) (2,304 ) Recoveries 282 816 1,098 Ending balance $ 57,955 $ 25,842 $ 83,797 Changes in allowance for loan losses for the six months ended June 30, 2017: Beginning balance $ 51,201 $ 27,067 $ 78,268 Provision for loan losses 8,476 1,803 10,279 Charge-offs (3,417 ) (4,461 ) (7,878 ) Recoveries 1,695 1,433 3,128 Ending balance $ 57,955 $ 25,842 $ 83,797 Changes in allowance for loan losses for the three months ended June 30, 2016: Beginning balance $ 44,668 $ 25,650 $ 70,318 Provision for loan losses 900 2,100 3,000 Charge-offs (2,542 ) (1,078 ) (3,620 ) Recoveries 1,202 606 1,808 Ending balance $ 44,228 $ 27,278 $ 71,506 Changes in allowance for loan losses for the six months ended June 30, 2016: Beginning balance $ 47,234 $ 26,094 $ 73,328 Provision for loan losses 1,900 2,600 4,500 Charge-offs (6,438 ) (2,640 ) (9,078 ) Recoveries 1,532 1,224 2,756 Ending balance $ 44,228 $ 27,278 $ 71,506 Allowance for loan losses balance at June 30, 2017 attributable to: Loans individually evaluated for impairment $ 5,673 $ 1,874 $ 7,547 Loans collectively evaluated for impairment 52,282 23,968 76,250 Loans acquired with deteriorated credit quality — — — Total $ 57,955 $ 25,842 $ 83,797 Recorded investment (loan balance) at June 30, 2017: Loans individually evaluated for impairment $ 78,266 $ 27,864 $ 106,130 Loans collectively evaluated for impairment 4,861,184 3,692,308 8,553,492 Loans acquired with deteriorated credit quality 3,191,712 1,816,038 5,007,750 Total $ 8,131,162 $ 5,536,210 $ 13,667,372 The following schedule presents, by loan portfolio segment, details regarding the balance in the allowance and the recorded investment in loans at December 31, 2016 by impairment evaluation method. (Dollars in thousands) Commercial Loan Portfolio Consumer Loan Portfolio Total Allowance for loan losses balance at December 31, 2016 attributable to: Loans individually evaluated for impairment $ 5,234 $ 4,158 $ 9,392 Loans collectively evaluated for impairment 45,967 22,909 68,876 Loans acquired with deteriorated credit quality — — — Total $ 51,201 $ 27,067 $ 78,268 Recorded investment (loan balance) at December 31, 2016: Loans individually evaluated for impairment $ 78,523 $ 28,346 $ 106,869 Loans collectively evaluated for impairment 4,026,526 3,325,006 7,351,532 Loans acquired with deteriorated credit quality 3,489,163 2,043,215 5,532,378 Total $ 7,594,212 $ 5,396,567 $ 12,990,779

Other Real Estate Owned and R33

Other Real Estate Owned and Repossessed Assets (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 $ 16,812 $ 375 Other additions (1) 3,776 2,556 Net payments received (202 ) — Disposals (5,976 ) (1,986 ) Write-downs (773 ) — Balance at June 30, 2017 $ 13,637 $ 945 Balance at January 1, 2016 $ 9,716 $ 219 Other additions (1) 2,155 1,215 Net payments received (85 ) (764 ) Disposals (3,230 ) (556 ) Write-downs (230 ) — Balance at June 30, 2016 $ 8,326 $ 114 (1) Includes loans transferred to other real estate owned and other repossessed assets.
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 expense" 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, 2017 Net gain (loss) on sale $ 768 $ (93 ) Write-downs (504 ) — Net operating expenses (710 ) (3 ) Total $ (446 ) $ (96 ) For the six months ended June 30, 2017 Net gain (loss) on sale $ 1,815 $ (171 ) Write-downs (773 ) — Net operating expenses (1,218 ) (6 ) Total $ (176 ) $ (177 ) For the three months ended June 30, 2016 Net gain (loss) on sale $ 1,320 $ 708 Write-downs (63 ) — Net operating expenses (260 ) 1 Total $ 997 $ 709 For the six months ended June 30, 2016 Net gain (loss) on sale $ 2,042 $ 700 Write-downs (230 ) — Net operating expenses (412 ) (3 ) Total $ 1,400 $ 697

Loan Servicing Rights (Tables)

Loan Servicing Rights (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 Fair value, beginning of period $ 320 $ 64,284 $ 64,604 Additions from loans sold with servicing retained 188 2,196 2,384 Changes in fair value due to: Reductions from pay-offs, pay downs and run-off (22 ) (642 ) (664 ) Changes in estimates of fair value (1) — (1,802 ) (1,802 ) Fair value, end of period $ 486 $ 64,036 $ 64,522 For the six months ended June 30, 2017 344 47741 48085 Fair value, beginning of period $ 344 $ 47,741 $ 48,085 Transfers based on new accounting policy election — 15,891 15,891 Additions from loans sold with servicing retained 188 3,949 4,137 Changes in fair value due to: 0 0 Reductions from pay-offs, pay downs and run-off (46 ) (1,224 ) (1,270 ) Changes in estimates of fair value (1) — (2,321 ) (2,321 ) Fair value, end of period $ 486 $ 64,036 $ 64,522 Principal balance of loans serviced for others that have servicing capitalized $ 47,349 $ 7,167,904 $ 7,215,253 (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.
Activity for capitalized loan servicing rights	Activity for LSRs and the related valuation allowance for the three and six months ended June 30, 2016 are as follows: (Dollars in thousands) For the Three Months Ended June 30, 2016 For the Six Months Ended June 30, 2016 Balance at beginning of period $ 10,478 $ 11,122 Additions 586 917 Amortization (975 ) (1,950 ) Change in valuation allowance (412 ) (412 ) Balance at end of period $ 9,677 $ 9,677
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, 2017 and December 31, 2016 . Mortgage As of June 30, 2017 Prepayment speed 0.0 - 35.7% Weighted average ("WA") discount rate 10.1 % Cost to service/per year $ 65 Ancillary income/per year $ 31 WA float range 1.2 % As of December 31, 2016 Prepayment speed 0.0 - 99.8% WA discount rate 10.1 % Cost to service/per year $65-$90 Ancillary income/per year $ 28 WA float range 1.0 %

Other Intangible Assets (Tables

Other Intangible Assets (Tables)	6 Months Ended
	Jun. 30, 2017
Goodwill and Intangible Assets Disclosure [Abstract]
Net carrying value of intangible assets	The following table shows the net carrying value of the Corporation’s other intangible assets: (Dollars in thousands) June 30, December 31, Core deposit intangible assets $ 37,235 $ 40,211 Non-compete intangible assets 87 — Total other intangible assets $ 37,322 $ 40,211
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 $ 59,143 $ 59,143 Accumulated amortization 21,908 18,932 Net carrying amount $ 37,235 $ 40,211

Derivative Instruments and Ba36

Derivative Instruments and Balance Sheet Offsetting (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 December 31, 2016 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 $ 400,000 $ 224 $ 282 $ — $ — $ — Total risk management purposes 400,000 224 282 — — — Customer-initiated and mortgage banking derivatives: Customer-initiated derivatives 1,055,917 8,636 9,152 600,598 4,406 4,141 Forward contracts related to mortgage loans to be delivered for sale 168,533 617 — 140,155 635 — Interest rate lock commitments 120,095 1,997 — 76,034 956 — Power Equity CD 38,540 2,062 2,062 36,807 2,218 2,218 Total customer-initiated and mortgage banking derivatives 1,383,085 13,312 11,214 853,594 8,215 6,359 Total gross derivatives $ 1,783,085 $ 13,536 $ 11,496 $ 853,594 $ 8,215 $ 6,359 (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 $538 thousand at June 30, 2017 and $99 thousand at December 31, 2016 .
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) 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, 2017 . (Dollars in thousands) Amount of gain (loss) recognized in other comprehensive income (Effective portion) Amount of gain (loss) reclassified from other comprehensive income to interest income or expense (Effective portion) Amount of gain (loss) recognized in other noninterest income (Ineffective portion) Three Months Ended June 30, 2017 Interest rate swaps designated as cash flow hedges $ (57 ) $ (409 ) $ — Six Months Ended June 30, 2017 Interest rate swaps designated as cash flow hedges $ (57 ) $ (409 ) $ — 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) 2017 2016 2017 2016 Forward contracts related to mortgage loans to be delivered for sale Net gain on sale of loans and other mortgage banking revenue $ 959 $ (409 ) $ (18 ) $ (642 ) Interest rate lock commitments Net gain on sale of loans and other mortgage banking revenue (181 ) 325 1,041 486 Customer-initiated derivatives Other noninterest income (551 ) — (781 ) — Total gain (loss) recognized in income $ 227 $ (84 ) $ 242 $ (156 )
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 (Dollars in thousands) Gross Gross amounts Net amounts Financial Collateral Net June 30, 2017 Offsetting derivative assets Derivative assets $ 8,838 $ — $ 8,838 $ — $ — $ 8,838 Offsetting derivative liabilities Derivative liabilities 9,434 — 9,434 — 9,037 397 December 31, 2016 Offsetting derivative assets Derivative assets $ 4,405 $ — $ 4,405 $ — $ — $ 4,405 Offsetting derivative liabilities Derivative liabilities 4,141 — 4,141 — 2,550 1,591
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 (Dollars in thousands) Gross Gross amounts Net amounts Financial Collateral Net June 30, 2017 Offsetting derivative assets Derivative assets $ 8,838 $ — $ 8,838 $ — $ — $ 8,838 Offsetting derivative liabilities Derivative liabilities 9,434 — 9,434 — 9,037 397 December 31, 2016 Offsetting derivative assets Derivative assets $ 4,405 $ — $ 4,405 $ — $ — $ 4,405 Offsetting derivative liabilities Derivative liabilities 4,141 — 4,141 — 2,550 1,591

Commitments, Contingencies an37

Commitments, Contingencies and Guarantees (Tables)	6 Months Ended
	Jun. 30, 2017
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) 2017 2016 2017 2016 Reserve balance at beginning of period $ 5,689 $ 3,825 $ 6,459 $ 4,048 Reserve reduction (220 ) — (990 ) (150 ) Charge-offs — — — (73 ) Ending reserve balance $ 5,469 $ 3,825 $ 5,469 $ 3,825 (Dollars in thousands) June 30, 2017 December 31, 2016 Reserve balance Liability for specific claims $ 9 $ 730 General allowance 5,460 5,729 Total reserve balance $ 5,469 $ 6,459

Borrowings (Tables)

Borrowings (Tables)	6 Months Ended
	Jun. 30, 2017
Debt Disclosure [Abstract]
Schedule of Other Borrowings	A summary of the Corporation's short- and long-term borrowings follows: June 30, 2017 December 31, 2016 (Dollars in thousands) Amount Weighted Average Rate (1) Amount Weighted Average Rate (1) Securities sold under agreements to repurchase with customers: Securities sold under agreements to repurchase with customers $ 310,042 0.26 % $ 343,047 0.16 % Short-term borrowings: FHLB advances: 0.96% - 1.40% fixed-rate notes 2,050,000 1.02 825,000 0.65 Long-term borrowings: FHLB advances: 0.92% - 7.44% fixed-rate notes due 2017 to 2020 (2) 351,324 1.30 438,538 1.24 Securities sold under agreements to repurchase: 1.48% - 2.75% fixed-rate notes due in 2017 (3) 9,048 2.11 19,144 3.17 Line-of-credit: floating-rate based on one-month LIBOR plus 1.75% 59,854 2.80 124,625 2.52 Subordinated debt obligations: floating-rate based on three-month LIBOR plus 1.45% - 2.85% due 2034 to 2035 (4) 11,354 3.42 11,285 3.14 Subordinated debt obligations: floating-rate based on three-month LIBOR plus 3.25% due in 2032 (5) 4,272 4.40 4,255 4.25 Total long-term borrowings 435,852 1.61 597,847 1.63 Total borrowings $ 2,795,894 1.03 % $ 1,765,894 0.89 % (1) Weighted average rate presented is the contractual rate which excludes premiums and discounts related to purchase accounting. (2) The June 30, 2017 balances include advances payable of $350.9 million and purchase accounting premiums of $0.5 million . The December 31, 2016 balance includes advances payable of $437.8 million and purchase accounting premiums of $0.7 million . (3) The June 30, 2017 balance includes advances payable of $9.0 million and purchase accounting premiums of $55 thousand . The December 31, 2016 balance includes advance payable of $19.0 million and purchase accounting premiums of $0.1 million . (4) The June 30, 2017 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.6 million . The December 31, 2016 balance includes advances payable of $15.0 million and purchase accounting discounts of $3.7 million . (5) The June 30, 2017 balance includes advances payable of $5.0 million and purchase accounting discounts of $0.7 million . The December 31, 2016 balance includes advances payable of $5.0 million and purchase accounting discounts of $0.7 million .
Schedule of Securities Sold Under Agreements to Repurchase	The remaining contractual maturity, excluding purchase accounting adjustments, of long-term securities under agreement to repurchase, is as follows: June 30, 2017 Remaining Contractual Maturities of the Agreements (Dollars in thousands) Overnight and continuous Up to 30 Days 30-90 Days Greater than 90 Days Total Securities sold under agreements to repurchase $ — $ — $ 4,000 $ 5,000 $ 9,000 Total borrowings $ — $ — $ 4,000 $ 5,000 $ 9,000 Amounts related to securities sold under agreements to repurchase not included in offsetting disclosure in Note 10 $ 9,000

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2017
Income Tax Disclosure [Abstract]
Schedule of reconciliation of expected income tax expense (benefit) at the federal statutory rate to the Company’s provision for income taxes and effective tax rate	A reconciliation of expected income tax expense at the federal statutory income tax rate and the amounts recorded in the Consolidated Financial Statements were as follows: Three Months Ended June 30, Six Months Ended June 30, 2017 2016 2017 2016 (Dollars in thousands) Amount Rate Amount Rate Amount Rate Amount Rate Tax at statutory rate $ 26,268 35.0 % $ 12,707 35.0 % $ 47,219 35.0 % $ 24,384 35.0 % Changes resulting from: Tax-exempt interest income (1,832 ) (2.4 ) (1,139 ) (3.1 ) (3,589 ) (2.7 ) (2,278 ) (3.3 ) State taxes, net of federal benefit 258 0.3 — — 470 0.4 — — Change in valuation allowance 38 — — — 49 — — — Bank-owned life insurance adjustments (335 ) (0.4 ) (287 ) (0.8 ) (679 ) (0.5 ) (355 ) (0.5 ) Income tax credits, net (1,102 ) (1.5 ) (834 ) (2.3 ) (1,797 ) (1.3 ) (1,631 ) (2.3 ) Tax benefits in excess of compensation costs on share-based payments (1) (248 ) (0.3 ) (68 ) (0.2 ) (6,382 ) (4.7 ) (411 ) (0.6 ) Other, net (11 ) — 153 0.4 2 — 580 0.8 Income tax expense $ 23,036 30.7 % $ 10,532 29.0 % $ 35,293 26.2 % $ 20,289 29.1 % (1) Represents excess tax benefits resulting from the exercise or settlement of share-based payment transactions.

Share-Based Compensation (Table

Share-Based Compensation (Tables)	6 Months Ended
	Jun. 30, 2017
Disclosure of Compensation Related Costs, Share-based Payments [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, 2017 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, 2016 407,939 $ 32.81 $ 6.15 2,453,395 $ 21.41 Granted 126,691 53.72 10.05 126,691 53.72 Exercised — — — (1,256,355 ) 16.19 Vested (81,584 ) 32.81 6.15 — — Forfeited/expired (10,337 ) 39.59 7.42 (10,337 ) 39.59 Outstanding at June 30, 2017 442,709 $ 38.64 $ 7.24 1,313,394 $ 29.39 Exercisable/vested at June 30, 2017 870,685 $ 24.68
Assumptions of Black-Scholes option pricing model	The fair value of the stock options granted during the six months ended June 30, 2017 was estimated on the date of grant using the Black-Scholes option pricing model with the following assumptions. Expected dividend yield 3.32 % Risk-free interest rate 2.06 % Expected stock price volatility 26.9 % Expected life of options – in years 6.0 Weighted average fair value of options granted $ 10.05
Summary of activity for restricted stock units and awards	The following table provides information regarding nonvested restricted stock awards: Nonvested restricted stock awards Number of Awards Weighted-average acquisition-date Nonvested at January 1, 2017 365,891 $ 46.23 Vested (61,049 ) 46.23 Forfeited (3,657 ) 46.23 Nonvested at June 30, 2017 301,185 $ 46.23 A summary of the activity for restricted stock units as of and for the six months ended June 30, 2017 is presented below: Number of Units Weighted-average grant date fair value per unit Outstanding at December 31, 2016 298,357 $ 32.81 Granted 162,771 52.10 Converted into shares of common stock (40,141 ) 26.86 Forfeited/expired (3,529 ) 47.27 Outstanding at June 30, 2017 417,458 $ 40.79

Pension and Other Postretirem41

Pension and Other Postretirement Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2017
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) 2017 2016 2017 2016 Defined Benefit Pension Plans Service cost $ 234 $ 277 $ 467 $ 554 Interest cost 1,301 1,358 2,603 2,716 Expected return on plan assets (2,217 ) (2,140 ) (4,434 ) (4,281 ) Amortization of unrecognized net loss 579 572 1,157 1,144 Net periodic benefit cost (income) $ (103 ) $ 67 $ (207 ) $ 133 Postretirement Benefit Plan Service cost $ 1 $ 2 $ 2 $ 4 Interest cost 23 33 47 66 Amortization of prior service cost — 29 — 58 Amortization of unrecognized net gain (40 ) (25 ) (81 ) (49 ) Net periodic benefit cost (income) $ (16 ) $ 39 $ (32 ) $ 79

Regulatory Capital (Tables)

Regulatory Capital (Tables)	6 Months Ended
	Jun. 30, 2017
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 Minimum Required for Capital Adequacy Purposes Plus 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 Capital Amount Ratio June 30, 2017 Total Capital to Risk-Weighted Assets Corporation $ 1,598,217 11.1 % $ 1,147,806 8.0 % $ 1,327,151 9.3 % N/A N/A Chemical Bank 1,608,525 11.2 1,144,292 8.0 1,323,088 9.3 $ 1,430,365 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,492,038 10.4 860,855 6.0 1,040,199 7.3 N/A N/A Chemical Bank 1,517,972 10.6 858,219 6.0 1,037,015 7.3 1,144,292 8.0 Common Equity Tier 1 Capital to Risk-Weighted Assets Corporation 1,492,038 10.4 645,641 4.5 824,986 5.8 N/A N/A Chemical Bank 1,517,972 10.6 643,664 4.5 822,460 5.8 929,737 6.5 Leverage Ratio Corporation 1,492,038 8.7 683,677 4.0 683,677 4.0 N/A N/A Chemical Bank 1,517,972 8.9 682,224 4.0 682,224 4.0 852,780 5.0 December 31, 2016 Total Capital to Risk-Weighted Assets Corporation $ 1,543,018 11.5 % $ 1,073,431 8.0 % $ 1,157,293 8.6 % N/A N/A Chemical Bank 1,608,980 12.0 1,068,560 8.0 1,152,041 8.6 $ 1,335,700 10.0 % Tier 1 Capital to Risk-Weighted Assets Corporation 1,441,209 10.7 805,073 6.0 888,935 6.6 N/A N/A Chemical Bank 1,522,711 11.4 801,420 6.0 884,901 6.6 1,068,560 8.0 Common Equity Tier 1 Capital to Risk-Weighted Asset Corporation 1,441,209 10.7 603,805 4.5 687,667 5.1 N/A N/A Chemical Bank 1,522,711 11.4 601,065 4.5 684,546 5.1 868,205 6.5 Leverage Ratio Corporation 1,441,209 9.0 643,603 4.0 643,603 4.0 N/A N/A Chemical Bank 1,522,711 9.5 641,457 4.0 641,457 4.0 801,822 5.0

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2017
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) 2017 2016 2017 2016 Net income $ 52,014 $ 25,775 $ 99,618 $ 49,380 Net income allocated to participating securities 219 — 446 — Net income allocated to common shareholders (1) $ 51,795 $ 25,775 $ 99,172 $ 49,380 Weighted average common shares - issued 71,122 38,258 71,046 38,228 Average unvested restricted share awards (303 ) — (321 ) — Weighted average common shares outstanding - basic 70,819 38,258 70,725 38,228 Effect of dilutive securities Weighted average common stock equivalents 624 342 704 332 Weighted average common shares outstanding - diluted 71,443 38,600 71,429 38,560 EPS available to common shareholders Basic earnings per common share $ 0.73 $ 0.67 $ 1.41 $ 1.29 Diluted earnings per common share $ 0.73 $ 0.67 $ 1.39 $ 1.28 (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 and warrants 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 Comprehensi44

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2017
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, 2017 , and 2016 : (Dollars in thousands) Unrealized gains Defined Benefit Pension Plans Unrealized gains (losses) on cash flow hedges, net of tax Total For the three months ended June 30, 2017 Beginning balance $ (12,420 ) $ (25,545 ) $ — $ (37,965 ) Other comprehensive income before reclassifications 3,593 — (466 ) 3,127 Amounts reclassified from accumulated other comprehensive income (50 ) 350 409 709 Net current period other comprehensive income 3,543 350 (57 ) 3,836 Ending balance $ (8,877 ) $ (25,195 ) $ (57 ) $ (34,129 ) For the three months ended June 30, 2016 Beginning balance $ 829 $ (27,519 ) $ — $ (26,690 ) Other comprehensive income before reclassifications 1,379 — — 1,379 Amounts reclassified from accumulated other comprehensive income (12 ) (375 ) — (387 ) Net current period other comprehensive income (loss) 1,367 (375 ) — 992 Ending balance $ 2,196 $ (27,894 ) $ — $ (25,698 ) For the six months ended June 30, 2017 Beginning balance $ (14,142 ) $ (25,894 ) $ — $ (40,036 ) Other comprehensive income (loss) before reclassifications 5,374 — (466 ) 4,908 Amounts reclassified from accumulated other comprehensive income (109 ) 699 409 999 Net current period other comprehensive income (loss) 5,265 699 (57 ) 5,907 Ending balance $ (8,877 ) $ (25,195 ) $ (57 ) $ (34,129 ) For the six months ended June 30, 2016 Beginning balance $ (1,888 ) $ (27,144 ) $ — $ (29,032 ) Other comprehensive income before reclassifications 4,108 — — 4,108 Amounts reclassified from accumulated other comprehensive income (24 ) (750 ) — (774 ) Net current period other comprehensive income 4,084 (750 ) — 3,334 Ending balance $ 2,196 $ (27,894 ) $ — $ (25,698 )
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, 2017 , and 2016 : (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, 2017 2016 2017 2016 Gains and losses on available-for-sale securities $ 77 $ 18 $ 167 $ 37 Gain on sale of investment securities (noninterest income) (27 ) (6 ) (58 ) (13 ) Income tax (expense)/benefit $ 50 $ 12 $ 109 $ 24 Net Income Amortization of defined benefit pension plan items $ (539 ) $ 577 $ (1,076 ) $ 1,154 Salaries, wages and employee benefits (operating expenses) 189 (202 ) 377 (404 ) Income tax (expense)/benefit $ (350 ) $ 375 (699 ) $ 750 Net Income (loss) Gains and losses on cash flow hedges $ 409 $ — $ 409 $ — Interest on short-term borrowings (interest expense) $ (409 ) $ — $ (409 ) $ — Net Income (loss)

Basis of Presentation and Sig45

Basis of Presentation and Significant Accounting Policies (Details) $ in Thousands		6 Months Ended
		Jun. 30, 2017Bank	Dec. 31, 2016USD ($)
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		7
Business Acquisition
Cumulative effect adjustment of change in accounting policy, net of tax impact | $	[1]		$ 3,659
Retained earnings
Business Acquisition
Cumulative effect adjustment of change in accounting policy, net of tax impact | $	[1]		$ 3,659
[1]	Refer to Note 1, Basis of Presentation and Significant Accounting Policies and Note 8, Loan Servicing Rights, for further details on the changes in accounting policy.

Mergers and Acquisitions - Text

Mergers and Acquisitions - Textual (Details) $ / shares in Units, $ in Thousands, shares in Millions	Aug. 31, 2016USD ($)$ / sharesshares	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)	Jun. 30, 2016USD ($)
Business Acquisition
Repayments of lines of credit	$ 25,000
Merger and acquisition-related transaction expenses		$ 465	$ 3,054	$ 4,632	$ 5,648
Talmer
Business Acquisition
Acquisition purchase price	$ 1,612,449
Stock consideration given (in shares) | shares	32.1
Exchange ratio of common stock issued	0.4725
Share price (dollars per share) | $ / shares	$ 1.61
Credit facility used for acquisition	$ 125,000
Repayments of lines of credit	$ 37,500

Mergers and Acquisitions - Asse

Mergers and Acquisitions - Assets Acquired and Liabilities Assumed (Details) - Talmer Bank $ in Thousands	Aug. 31, 2016USD ($)
Consideration paid:
Stock	$ 1,504,811
Cash	107,638
Total consideration	1,612,449
Fair value of identifiable assets acquired:
Cash and cash equivalents	433,352
Investment securities:
Available-for-sale	808,894
Held-to-maturity	1,657
Loans held-for-sale	244,916
Loans	4,882,402
Premises and equipment	38,793
Loan servicing rights	42,462
Other intangible assets	19,088
Interest receivable and other assets	395,119
Total identifiable assets acquired	6,866,683
Fair value of liabilities assumed:
Noninterest-bearing deposits	1,236,902
Interest-bearing deposits	4,057,716
Interest payable and other liabilities	99,482
Securities sold under agreements to repurchase with customers	19,704
Short-term borrowings	387,500
Long-term borrowings	299,597
Total liabilities assumed	6,100,901
Fair value of net identifiable assets acquired	765,782
Goodwill resulting from acquisition	$ 846,667

Mergers and Acquisitions - Loan

Mergers and Acquisitions - Loans Accounted for Under ASC 310-30 (Details) - Talmer Bank $ in Thousands	Aug. 31, 2016USD ($)
Accounted for under ASC 310-30:
Contractual cash flows	$ 5,968,488
Contractual cash flows not expected to be collected (nonaccretable difference)	223,959
Expected cash flows	5,744,529
Interest component of expected cash flows (accretable yield)	862,127
Fair value at acquisition	$ 4,882,402

Mergers and Acquisitions - Pro

Mergers and Acquisitions - Pro Forma Information (Details) - Talmer Bank - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Business Acquisition
Net interest and other income	$ 179,516	$ 168,130	$ 347,623	$ 326,100
Net Income	$ 52,014	$ 42,111	$ 99,618	$ 81,163
Earnings per share:
Basic (dollars per share)	$ 0.73	$ 0.60	$ 1.41	$ 1.15
Diluted (dollars per share)	$ 0.73	$ 0.59	$ 1.39	$ 1.14

Fair Value Measurements - Asset

Fair Value Measurements - Assets on a Recurring Basis (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	$ 1,767,478		$ 1,234,964
Loan servicing rights	64,522	$ 64,604	48,085
U.S. Treasury securities
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,793		5,793
Government sponsored agencies
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	247,474		215,011
State and political subdivisions
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	292,035		300,088
Residential mortgage-backed securities
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	292,912		272,282
Collateralized mortgage obligations
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	733,187		320,025
Corporate bonds
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	158,168		89,474
Preferred stock and trust preferred securities
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	37,909		32,291
Recurring
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	1,767,478		1,234,964
Loans held-for-sale	65,371		81,830
Loan servicing rights	64,522		48,085
Total derivatives	13,536		8,215
Total assets measured at fair value on a recurring basis	1,910,907		1,373,094
Total derivatives	11,496		6,359
Total liabilities at fair value	11,496		6,359
Recurring | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,793		5,793
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	5,793		5,793
Total derivatives	0		0
Total liabilities at fair value	0		0
Recurring | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	1,761,685		1,229,171
Loans held-for-sale	65,371		81,830
Loan servicing rights	0		0
Total derivatives	13,536		8,215
Total assets measured at fair value on a recurring basis	1,840,592		1,319,216
Total derivatives	11,496		6,359
Total liabilities at fair value	11,496		6,359
Recurring | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Loans held-for-sale	0		0
Loan servicing rights	64,522		48,085
Total derivatives	0		0
Total assets measured at fair value on a recurring basis	64,522		48,085
Total derivatives	0		0
Total liabilities at fair value	0		0
Recurring | Customer-initiated derivatives
Summary of assets measured at fair value on a recurring basis
Total derivatives	8,636		4,406
Total derivatives	9,152		4,141
Recurring | 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
Recurring | Customer-initiated derivatives | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	8,636		4,406
Total derivatives	9,152		4,141
Recurring | 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
Recurring | Forward contracts related to mortgage loans to be delivered for sale
Summary of assets measured at fair value on a recurring basis
Total derivatives	617		635
Recurring | 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
Recurring | 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	617		635
Recurring | 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
Recurring | Interest rate lock commitments
Summary of assets measured at fair value on a recurring basis
Total derivatives	1,997		956
Recurring | 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
Recurring | Interest rate lock commitments | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	1,997		956
Recurring | Interest rate lock commitments | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0		0
Recurring | Power Equity CD
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,062		2,218
Total derivatives	2,062		2,218
Recurring | 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
Recurring | Power Equity CD | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	2,062		2,218
Total derivatives	2,062		2,218
Recurring | 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
Recurring | Risk management derivatives
Summary of assets measured at fair value on a recurring basis
Total derivatives	224
Total derivatives	282
Recurring | 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
Total derivatives	0
Recurring | Risk management derivatives | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Total derivatives	224
Total derivatives	282
Recurring | Risk management derivatives | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Total derivatives	0
Total derivatives	0
Recurring | U.S. Treasury securities
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,793		5,793
Recurring | U.S. Treasury securities | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	5,793		5,793
Recurring | U.S. Treasury securities | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | U.S. Treasury securities | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Government sponsored agencies
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	247,474		215,011
Recurring | Government sponsored agencies | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Government sponsored agencies | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	247,474		215,011
Recurring | Government sponsored agencies | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | State and political subdivisions
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	292,035		300,088
Recurring | 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
Available-for-sale, at fair value	0		0
Recurring | State and political subdivisions | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	292,035		300,088
Recurring | State and political subdivisions | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Residential mortgage-backed securities
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	292,912		272,282
Recurring | 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
Available-for-sale, at fair value	0		0
Recurring | Residential mortgage-backed securities | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	292,912		272,282
Recurring | Residential mortgage-backed securities | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Collateralized mortgage obligations
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	733,187		320,025
Recurring | Collateralized mortgage obligations | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Collateralized mortgage obligations | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	733,187		320,025
Recurring | Collateralized mortgage obligations | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Corporate bonds
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	158,168		89,474
Recurring | Corporate bonds | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Corporate bonds | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	158,168		89,474
Recurring | Corporate bonds | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Preferred stock and trust preferred securities
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	37,909		32,291
Recurring | Preferred stock and trust preferred securities | Quoted Prices In Active Markets for Identical Assets (Level 1)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	0		0
Recurring | Preferred stock and trust preferred securities | Significant Other Observable Inputs (Level 2)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	37,909		32,291
Recurring | Preferred stock and trust preferred securities | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a recurring basis
Available-for-sale, at fair value	$ 0		$ 0

Fair Value Measurements - Chang

Fair Value Measurements - Changes in Level 3 Assets (Details) - Recurring - Loan servicing rights - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Changes in Level 3 Assets Measured at Fair Value on a Recurring Basis
Balance, beginning of period	$ 64,604	$ 48,085
Transfer in based on new accounting policy election	0	15,891
Gains (losses): Recorded in earnings (realized):
Recorded in Net gain on sale of loans and other mortgage banking revenue	(2,466)	(3,591)
New originations	2,384	4,137
Balance, end of period	$ 64,522	$ 64,522

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, 2017	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Aggregate fair value	$ 65,371	$ 81,830
Contractual balance	63,162	81,009
Unrealized gain (loss)	$ 2,209	$ 821

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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	$ 15,155	$ 2,155	$ 22,427	$ 3,470
Interest income
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	463	20	1,014	39
Change in fair value
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	787	0	1,388	0
Net gain on sale of loans and other mortgage banking revenue
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Total included in earnings	$ 13,905	$ 2,135	$ 20,025	$ 3,431

Fair Value Measurements - Textu

Fair Value Measurements - Textual (Details) - USD ($)	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value Measurements (Textual) [Abstract]
Impairment of goodwill	$ 0	$ 0
Core deposit intangible assets
Fair Value Measurements (Textual) [Abstract]
Impairment valuation allowance	$ 0	0
Non-compete intangible assets
Fair Value Measurements (Textual) [Abstract]
Expected life of intangible assets	1 year
Loan servicing rights
Fair Value Measurements (Textual) [Abstract]
Impairment valuation allowance		8,000
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	10.00%
Total Impaired Loans | Maximum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	25.00%
Other Real Estate and Repossessed Assets | Minimum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	10.00%
Other Real Estate and Repossessed Assets | Maximum
Fair Value Measurements (Textual) [Abstract]
Percentage of discount factors used to determine fair value	25.00%
Measured on a Recurring Basis
Fair Value Measurements (Textual) [Abstract]
Liabilities recorded at fair value	$ 11,496,000	6,359,000
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 - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	$ 67,505	$ 63,572
Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	67,505	63,572
Impaired originated loans
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	63,694	62,184
Impaired originated loans | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	63,694	62,184
Other real estate/repossessed assets
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	3,811	1,386
Other real estate/repossessed assets | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis	$ 3,811	1,386
Loan servicing rights
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis		2
Loan servicing rights | Significant Unobservable Inputs (Level 3)
Summary of assets measured at fair value on a nonrecurring basis
Total assets measured at fair value on a nonrecurring basis		$ 2

Fair Value Measurements - Level

Fair Value Measurements - Level 3 Assets, Nonrecurring Basis (Details) - Nonrecurring - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total assets measured at fair value on a nonrecurring basis	$ 67,505	$ 63,572
Impaired originated loans
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total assets measured at fair value on a nonrecurring basis	63,694	62,184
Other real estate/repossessed assets
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total assets measured at fair value on a nonrecurring basis	3,811	1,386
Level 3
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total assets measured at fair value on a nonrecurring basis	67,505	63,572
Level 3 | Impaired originated loans
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total assets measured at fair value on a nonrecurring basis	$ 63,694	62,184
Level 3 | Impaired originated loans | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	10.00%
Level 3 | Impaired originated loans | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	25.00%
Level 3 | Other real estate/repossessed assets
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Total assets measured at fair value on a nonrecurring basis	$ 3,811	$ 1,386
Level 3 | Other real estate/repossessed assets | Minimum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	10.00%
Level 3 | Other real estate/repossessed assets | Maximum
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Discount rate	25.00%

Fair Value Measurements - Carry

Fair Value Measurements - Carrying Amounts and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investment securities:
Held-to-maturity	$ 640,043	$ 608,531
Nonrecurring
Deposits:
Assets, Fair Value Disclosure, Nonrecurring	67,505	63,572
Nonrecurring | Impaired originated loans
Deposits:
Assets, Fair Value Disclosure, Nonrecurring	63,694	62,184
Level 3 | Nonrecurring
Deposits:
Assets, Fair Value Disclosure, Nonrecurring	67,505	63,572
Level 3 | Nonrecurring | Impaired originated loans
Deposits:
Assets, Fair Value Disclosure, Nonrecurring	63,694	62,184
Carrying Amount | Level 1
Financial assets:
Cash and cash equivalents	619,241	474,402
Carrying Amount | Level 2
Investment securities:
Held-to-maturity	645,105	622,927
Nonmarketable equity securities	180,196	97,350
Interest receivable	45,832	42,235
Bank-owned life insurance	145,671	143,718
Deposits:
Deposits without defined maturities	10,217,235	9,862,755
Time deposits	2,987,132	3,010,367
Total deposits	13,204,367	12,873,122
Interest payable	5,112	5,415
Securities sold under agreements to repurchase with customers	310,042	343,047
Short-term borrowings	2,050,000	825,000
Long-term borrowings	435,852	597,847
Carrying Amount | Level 3
Investment securities:
Held-to-maturity	500	500
Net loans	13,583,575	12,912,511
Fair Value | Level 1
Financial assets:
Cash and cash equivalents	619,241	474,402
Fair Value | Level 2
Investment securities:
Held-to-maturity	639,683	608,221
Nonmarketable equity securities	180,196	97,350
Interest receivable	45,832	42,235
Bank-owned life insurance	145,671	143,718
Deposits:
Deposits without defined maturities	10,217,235	9,862,755
Time deposits	2,987,779	3,010,048
Total deposits	13,205,014	12,872,803
Interest payable	5,112	5,415
Securities sold under agreements to repurchase with customers	310,042	343,047
Short-term borrowings	2,048,744	825,000
Long-term borrowings	431,345	591,227
Fair Value | Level 3
Investment securities:
Held-to-maturity	360	310
Net loans	$ 13,758,368	$ 13,069,315

Investment Securities - Availab

Investment Securities - Available-For-Sale Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Available-for-sale Securities
Amortized Cost	$ 1,781,135	$ 1,256,721
Unrealized Gains	3,079	1,566
Unrealized Losses	16,736	23,323
Available-for-sale, at fair value	1,767,478	1,234,964
U.S. Treasury securities
Available-for-sale Securities
Amortized Cost	5,795	5,788
Unrealized Gains	0	5
Unrealized Losses	2	0
Available-for-sale, at fair value	5,793	5,793
Government sponsored agencies
Available-for-sale Securities
Amortized Cost	248,021	216,890
Unrealized Gains	619	189
Unrealized Losses	1,166	2,068
Available-for-sale, at fair value	247,474	215,011
State and political subdivisions
Available-for-sale Securities
Amortized Cost	297,560	311,704
Unrealized Gains	114	163
Unrealized Losses	5,639	11,779
Available-for-sale, at fair value	292,035	300,088
Residential mortgage-backed securities
Available-for-sale Securities
Amortized Cost	296,898	276,162
Unrealized Gains	26	112
Unrealized Losses	4,012	3,992
Available-for-sale, at fair value	292,912	272,282
Collateralized mortgage obligations
Available-for-sale Securities
Amortized Cost	737,963	323,965
Unrealized Gains	173	63
Unrealized Losses	4,949	4,003
Available-for-sale, at fair value	733,187	320,025
Corporate bonds
Available-for-sale Securities
Amortized Cost	158,828	90,859
Unrealized Gains	276	16
Unrealized Losses	936	1,401
Available-for-sale, at fair value	158,168	89,474
Preferred stock and trust preferred securities
Available-for-sale Securities
Amortized Cost	36,070	31,353
Unrealized Gains	1,871	1,018
Unrealized Losses	32	80
Available-for-sale, at fair value	$ 37,909	$ 32,291

Investment Securities - Held-To

Investment Securities - Held-To-Maturity Investment (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Held-to-maturity Securities
Amortized Cost	$ 645,605	$ 623,427
Unrealized Gains	5,281	2,648
Unrealized Losses	10,843	17,544
Held-to-maturity, fair value	640,043	608,531
State and political subdivisions
Held-to-maturity Securities
Amortized Cost	645,105	622,927
Unrealized Gains	5,281	2,648
Unrealized Losses	10,703	17,354
Held-to-maturity, fair value	639,683	608,221
Trust preferred securities
Held-to-maturity Securities
Amortized Cost	500	500
Unrealized Gains	0	0
Unrealized Losses	140	190
Held-to-maturity, fair value	$ 360	$ 310

Investment Securities - Gains a

Investment Securities - Gains and (Losses) Recognized in Earnings (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)security	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)security	Jun. 30, 2016USD ($)
Investments, Debt and Equity Securities [Abstract]
Securities in unrealized loss positions, qualitative disclosure, number of positions (in security) | security	1,351		1,351
Proceeds	$ 10,050	$ 4,356	$ 10,050	$ 5,000
Gross gains	$ 77	$ 18	$ 167	$ 37

Investment Securities - Maturit

Investment Securities - Maturities of Debt Securities (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Investment Securities Available-for-Sale: Amortized Cost
Due in one year or less	$ 345,833
Due after one year through five years	731,523
Due after five years through ten years	488,832
Due after ten years	213,558
Preferred stock	1,389
Total	1,781,135
Investment Securities Available-for-Sale: Fair Value
Due in one year or less	344,064
Due after one year through five years	726,231
Due after five years through ten years	485,107
Due after ten years	210,229
Preferred stock	1,847
Total	1,767,478
Investment Securities Held-to-Maturity: Amortized Cost
Due in one year or less	85,434
Due after one year through five years	253,002
Due after five years through ten years	143,396
Due after ten years	163,773
Total	645,605	$ 623,427
Investment Securities Held-to-Maturity: Fair Value
Due in one year or less	85,398
Due after one year through five years	251,488
Due after five years through ten years	141,140
Due after ten years	162,017
Total	640,043	608,531
Securities with amortized cost pledged to secure borrowings and deposits	$ 1,050,000	$ 794,000

Investment Securities - Gross U

Investment Securities - Gross Unrealized Losses (Details) $ in Thousands	Jun. 30, 2017USD ($)security	Dec. 31, 2016USD ($)
Schedule of Investments [Line Items]
Total number of securities, available-for-sale and held-to-maturity (in security) | security	2,336
Securities in unrealized loss positions, qualitative disclosure, number of positions (in security) | security	1,351
Fair Value
Less Than 12 Months	$ 1,751,829	$ 1,478,240
12 Months or More	70,324	56,897
Total	1,822,153	1,535,137
Gross Unrealized Losses
Less Than 12 Months	26,292	39,116
12 Months or More	1,287	1,751
Total	27,579	40,867
U.S. Treasury securities
Fair Value
Less Than 12 Months	5,793
12 Months or More	0
Total	5,793
Gross Unrealized Losses
Less Than 12 Months	2
12 Months or More	0
Total	2
Government sponsored agencies
Fair Value
Less Than 12 Months	104,655	105,702
12 Months or More	10,816	15,023
Total	115,471	120,725
Gross Unrealized Losses
Less Than 12 Months	1,042	1,707
12 Months or More	124	361
Total	1,166	2,068
State and political subdivisions
Fair Value
Less Than 12 Months	614,276	758,063
12 Months or More	46,588	26,810
Total	660,864	784,873
Gross Unrealized Losses
Less Than 12 Months	15,504	28,158
12 Months or More	838	975
Total	16,342	29,133
Residential mortgage-backed securities
Fair Value
Less Than 12 Months	284,277	244,239
12 Months or More	0	0
Total	284,277	244,239
Gross Unrealized Losses
Less Than 12 Months	4,012	3,992
12 Months or More	0	0
Total	4,012	3,992
Collateralized mortgage obligations
Fair Value
Less Than 12 Months	627,054	279,001
12 Months or More	11,061	14,754
Total	638,115	293,755
Gross Unrealized Losses
Less Than 12 Months	4,765	3,778
12 Months or More	184	225
Total	4,949	4,003
Corporate bonds
Fair Value
Less Than 12 Months	111,931	80,536
12 Months or More	1,499	0
Total	113,430	80,536
Gross Unrealized Losses
Less Than 12 Months	935	1,401
12 Months or More	1	0
Total	936	1,401
Trust preferred securities
Fair Value
Less Than 12 Months	3,843	10,699
12 Months or More	360	310
Total	4,203	11,009
Gross Unrealized Losses
Less Than 12 Months	32	80
12 Months or More	140	190
Total	$ 172	$ 270

Loans - Textual (Details)

Loans - Textual (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2017USD ($)segmenttenantdirectorclass_of_loanexecutive	Dec. 31, 2016USD ($)
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	$ 2,000
Maximum value of loan that requires regional loan committee approval	5,000
Total troubled debt restructurings	80,941	$ 93,066
Residential mortgage loans in process of foreclosure	4,600	7,300
Commitment to lend additional funds to borrowers whose terms have been modified in TDRs	1,600
Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	25,705	30,531
Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	55,236	62,535
Consumer loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	19,931	22,281
Consumer loan portfolio | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	4,409	5,134
Consumer loan portfolio | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	15,522	17,147
Commercial loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	61,010	70,785
Commercial loan portfolio | Nonperforming
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	21,296	25,397
Commercial loan portfolio | Performing
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total troubled debt restructurings	$ 39,714	$ 45,388
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	$ 2,000
Number of bank executives and senior officers with credit decision limits similar to group loan authorities (in executive) | executive	6
Minimum value of loan requires executive and senior officer approval	$ 2,000
Maximum value of loan requires executive and senior officer approval	3,500
Minimum value of loan requires group loan authority approval	5,000
Maximum value of loan requires group loan authority approval	$ 10,000
Number of members of the board of directors in loan committee (in director) | director	8
Commercial | Minimum | Commercial loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Minimum value of loans requiring only director loan committee approval	$ 10,000
Minimum value of loans depending on risk rating and requires credit action from board of directors	25,000
Commercial | Maximum | Commercial loan portfolio
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other loans requiring director loan committee approval depending on risk rating and credit action required	$ 10,000

Loans - Summary of Loans (Detai

Loans - Summary of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Summary of loans under portfolio
Total loans	$ 13,667,372	$ 12,990,779
Deferred income	20,000	14,800
Commercial loan portfolio
Summary of loans under portfolio
Total loans	8,131,162	7,594,212
Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	3,360,161	3,217,300
Commercial loan portfolio | Commercial real estate
Summary of loans under portfolio
Total loans	4,324,323	3,973,140
Commercial loan portfolio | Real estate construction and land development
Summary of loans under portfolio
Total loans	446,678	403,772
Consumer loan portfolio
Summary of loans under portfolio
Total loans	5,536,210	5,396,567
Consumer loan portfolio | Residential mortgage
Summary of loans under portfolio
Total loans	3,125,397	3,086,474
Consumer loan portfolio | Consumer installment
Summary of loans under portfolio
Total loans	1,553,967	1,433,884
Consumer loan portfolio | Home equity
Summary of loans under portfolio
Total loans	856,846	876,209
Originated
Summary of loans under portfolio
Total loans	8,659,622	7,458,401
Originated | Commercial
Summary of loans under portfolio
Total loans	2,184,283	1,901,526
Originated | Commercial real estate
Summary of loans under portfolio
Total loans	2,405,772	1,921,799
Originated | Real estate construction and land development
Summary of loans under portfolio
Total loans	349,395	281,724
Originated | Residential mortgage
Summary of loans under portfolio
Total loans	1,683,550	1,475,342
Originated | Consumer installment
Summary of loans under portfolio
Total loans	1,429,088	1,282,588
Originated | Home equity
Summary of loans under portfolio
Total loans	607,534	595,422
Originated | Commercial loan portfolio
Summary of loans under portfolio
Total loans	4,939,450	4,105,049
Originated | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	2,184,283	1,901,526
Originated | Commercial loan portfolio | Commercial real estate
Summary of loans under portfolio
Total loans	2,405,772	1,921,799
Originated | Commercial loan portfolio | Real estate construction and land development
Summary of loans under portfolio
Total loans	349,395	281,724
Originated | Consumer loan portfolio
Summary of loans under portfolio
Total loans	3,720,172	3,353,352
Originated | Consumer loan portfolio | Residential mortgage
Summary of loans under portfolio
Total loans	1,683,550	1,475,342
Originated | Consumer loan portfolio | Consumer installment
Summary of loans under portfolio
Total loans	1,429,088	1,282,588
Originated | Consumer loan portfolio | Home equity
Summary of loans under portfolio
Total loans	607,534	595,422
Acquired
Summary of loans under portfolio
Total loans	5,007,750	5,532,378
Acquired | Commercial loan portfolio
Summary of loans under portfolio
Total loans	3,191,712	3,489,163
Acquired | Commercial loan portfolio | Commercial
Summary of loans under portfolio
Total loans	1,175,878	1,315,774
Acquired | Commercial loan portfolio | Commercial real estate
Summary of loans under portfolio
Total loans	1,918,551	2,051,341
Acquired | Commercial loan portfolio | Real estate construction and land development
Summary of loans under portfolio
Total loans	97,283	122,048
Acquired | Consumer loan portfolio
Summary of loans under portfolio
Total loans	1,816,038	2,043,215
Acquired | Consumer loan portfolio | Residential mortgage
Summary of loans under portfolio
Total loans	1,441,847	1,611,132
Acquired | Consumer loan portfolio | Consumer installment
Summary of loans under portfolio
Total loans	124,879	151,296
Acquired | Consumer loan portfolio | Home equity
Summary of loans under portfolio
Total loans	$ 249,312	$ 280,787

Loans - Activity for Accretable

Loans - Activity for Accretable Yield (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Activity for accretable yield
Balance at beginning of period	$ 1,000,408	$ 274,614	$ 1,039,971	$ 298,257
Accretion recognized in interest income	(62,614)	(17,478)	(122,801)	(34,440)
Net reclassification (to) from nonaccretable difference	100,425	(596)	121,049	(7,277)
Balance at end of period	1,038,219	256,540	1,038,219	256,540
Talmer
Activity for accretable yield
Balance at beginning of period	774,778	0	798,210	0
Accretion recognized in interest income	(45,091)	0	(89,662)	0
Net reclassification (to) from nonaccretable difference	71,682	0	92,821	0
Balance at end of period	801,369	0	801,369	0
Lake Michigan
Activity for accretable yield
Balance at beginning of period	113,211	137,975	121,416	152,999
Accretion recognized in interest income	(7,583)	(8,338)	(14,849)	(17,291)
Net reclassification (to) from nonaccretable difference	15,944	(4,294)	15,005	(10,365)
Balance at end of period	121,572	125,343	121,572	125,343
Monarch
Activity for accretable yield
Balance at beginning of period	26,055	33,235	27,182	34,558
Accretion recognized in interest income	(1,159)	(1,385)	(2,340)	(2,836)
Net reclassification (to) from nonaccretable difference	(626)	(991)	(572)	(863)
Balance at end of period	24,270	30,859	24,270	30,859
North-western
Activity for accretable yield
Balance at beginning of period	64,897	76,368	69,847	82,623
Accretion recognized in interest income	(5,467)	(4,028)	(9,359)	(8,029)
Net reclassification (to) from nonaccretable difference	11,782	1,406	10,724	(848)
Balance at end of period	71,212	73,746	71,212	73,746
OAK
Activity for accretable yield
Balance at beginning of period	21,467	27,036	23,316	28,077
Accretion recognized in interest income	(3,314)	(3,727)	(6,591)	(6,284)
Net reclassification (to) from nonaccretable difference	1,643	3,283	3,071	4,799
Balance at end of period	$ 19,796	$ 26,592	$ 19,796	$ 26,592

Loans - Commercial Loans by Ris

Loans - Commercial Loans by Risk Rating Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 13,667,372	$ 12,990,779
Originated
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,659,622	7,458,401
Originated | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,184,283	1,901,526
Originated | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,405,772	1,921,799
Originated | Real estate construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	349,395	281,724
Acquired
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,007,750	5,532,378
Commercial loan portfolio
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,131,162	7,594,212
Commercial loan portfolio | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,763,613	7,167,397
Commercial loan portfolio | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	156,325	192,013
Commercial loan portfolio | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	206,427	233,479
Commercial loan portfolio | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,797	1,323
Commercial loan portfolio | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,360,161	3,217,300
Commercial loan portfolio | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,324,323	3,973,140
Commercial loan portfolio | Real estate construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	446,678	403,772
Commercial loan portfolio | Originated
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,939,450	4,105,049
Commercial loan portfolio | Originated | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,792,613	3,934,033
Commercial loan portfolio | Originated | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	60,891	81,947
Commercial loan portfolio | Originated | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	81,317	87,999
Commercial loan portfolio | Originated | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	4,629	1,070
Commercial loan portfolio | Originated | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,184,283	1,901,526
Commercial loan portfolio | Originated | Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,101,781	1,803,750
Commercial loan portfolio | Originated | Commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	31,051	44,809
Commercial loan portfolio | Originated | Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	47,871	51,898
Commercial loan portfolio | Originated | Commercial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,580	1,069
Commercial loan portfolio | Originated | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,405,772	1,921,799
Commercial loan portfolio | Originated | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,341,493	1,849,315
Commercial loan portfolio | Originated | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	29,840	36,981
Commercial loan portfolio | Originated | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	33,390	35,502
Commercial loan portfolio | Originated | Commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,049	1
Commercial loan portfolio | Originated | Real estate construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	349,395	281,724
Commercial loan portfolio | Originated | Real estate construction and land development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	349,339	280,968
Commercial loan portfolio | Originated | Real estate construction and land development | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	157
Commercial loan portfolio | Originated | Real estate construction and land development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	56	599
Commercial loan portfolio | Originated | Real estate construction and land development | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	0	0
Commercial loan portfolio | Acquired
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,191,712	3,489,163
Commercial loan portfolio | Acquired | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,971,000	3,233,364
Commercial loan portfolio | Acquired | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	95,434	110,066
Commercial loan portfolio | Acquired | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	125,110	145,480
Commercial loan portfolio | Acquired | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	168	253
Commercial loan portfolio | Acquired | Commercial
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,175,878	1,315,774
Commercial loan portfolio | Acquired | Commercial | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,100,238	1,218,848
Commercial loan portfolio | Acquired | Commercial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	30,686	46,643
Commercial loan portfolio | Acquired | Commercial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	44,951	50,283
Commercial loan portfolio | Acquired | Commercial | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	3	0
Commercial loan portfolio | Acquired | Commercial real estate
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,918,551	2,051,341
Commercial loan portfolio | Acquired | Commercial real estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,777,461	1,897,011
Commercial loan portfolio | Acquired | Commercial real estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	62,807	61,441
Commercial loan portfolio | Acquired | Commercial real estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	78,118	92,636
Commercial loan portfolio | Acquired | Commercial real estate | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	165	253
Commercial loan portfolio | Acquired | Real estate construction and land development
Financing Receivable, Recorded Investment [Line Items]
Total loans	97,283	122,048
Commercial loan portfolio | Acquired | Real estate construction and land development | Pass
Financing Receivable, Recorded Investment [Line Items]
Total loans	93,301	117,505
Commercial loan portfolio | Acquired | Real estate construction and land development | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,941	1,982
Commercial loan portfolio | Acquired | Real estate construction and land development | Substandard
Financing Receivable, Recorded Investment [Line Items]
Total loans	2,041	2,561
Commercial loan portfolio | Acquired | Real estate construction and land development | Doubtful
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 0	$ 0

Loans - Consumer Loans by Risk

Loans - Consumer Loans by Risk Rating Categories (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 13,667,372	$ 12,990,779
Originated
Financing Receivable, Recorded Investment [Line Items]
Total loans	8,659,622	7,458,401
Originated | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,683,550	1,475,342
Originated | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,429,088	1,282,588
Originated | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	607,534	595,422
Acquired
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,007,750	5,532,378
Consumer loan portfolio
Financing Receivable, Recorded Investment [Line Items]
Total loans	5,536,210	5,396,567
Consumer loan portfolio | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,125,397	3,086,474
Consumer loan portfolio | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,553,967	1,433,884
Consumer loan portfolio | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	856,846	876,209
Consumer loan portfolio | Originated
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,720,172	3,353,352
Consumer loan portfolio | Originated | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,683,550	1,475,342
Consumer loan portfolio | Originated | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,429,088	1,282,588
Consumer loan portfolio | Originated | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	607,534	595,422
Consumer loan portfolio | Originated | Performing
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,707,830	3,342,153
Consumer loan portfolio | Originated | Performing | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,675,836	1,468,373
Consumer loan portfolio | Originated | Performing | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,428,331	1,281,709
Consumer loan portfolio | Originated | Performing | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	603,663	592,071
Consumer loan portfolio | Originated | Nonperforming
Financing Receivable, Recorded Investment [Line Items]
Total loans	12,342	11,199
Consumer loan portfolio | Originated | Nonperforming | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	7,714	6,969
Consumer loan portfolio | Originated | Nonperforming | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Total loans	757	879
Consumer loan portfolio | Originated | Nonperforming | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	3,871	3,351
Consumer loan portfolio | Acquired
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,816,038	2,043,215
Consumer loan portfolio | Acquired | Residential mortgage
Financing Receivable, Recorded Investment [Line Items]
Total loans	1,441,847	1,611,132
Consumer loan portfolio | Acquired | Consumer installment
Financing Receivable, Recorded Investment [Line Items]
Total loans	124,879	151,296
Consumer loan portfolio | Acquired | Home equity
Financing Receivable, Recorded Investment [Line Items]
Total loans	$ 249,312	$ 280,787

Loans - Nonperforming Loans (De

Loans - Nonperforming Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Summary of nonperforming loans
Total accruing loans contractually past due 90 days or more as to interest or principal payments	$ 2,346	$ 1,283
Commercial
Summary of nonperforming loans
Total accruing loans contractually past due 90 days or more as to interest or principal payments	58	11
Commercial real estate
Summary of nonperforming loans
Total accruing loans contractually past due 90 days or more as to interest or principal payments	262	277
Home equity
Summary of nonperforming loans
Total accruing loans contractually past due 90 days or more as to interest or principal payments	2,026	995
Nonperforming
Summary of nonperforming loans
Total nonaccrual loans	50,894	44,334
Other real estate owned and repossessed assets	14,582	17,187
Total nonperforming assets	65,476	61,521
Nonperforming | Commercial
Summary of nonperforming loans
Total nonaccrual loans	18,773	13,178
Nonperforming | Commercial real estate
Summary of nonperforming loans
Total nonaccrual loans	19,723	19,877
Nonperforming | Real estate construction and land development
Summary of nonperforming loans
Total nonaccrual loans	56	80
Nonperforming | Residential mortgage
Summary of nonperforming loans
Total nonaccrual loans	7,714	6,969
Nonperforming | Consumer installment
Summary of nonperforming loans
Total nonaccrual loans	757	879
Nonperforming | Home equity
Summary of nonperforming loans
Total nonaccrual loans	$ 3,871	$ 3,351

Loans - Aging Status of Loans (

Loans - Aging Status of Loans (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Schedule representing the aging status of the recorded investment in loans by classes
Total loans	$ 13,667,372	$ 12,990,779
90 days or more past due and still accruing	2,346	1,283
Commercial
Schedule representing the aging status of the recorded investment in loans by classes
90 days or more past due and still accruing	58	11
Commercial real estate
Schedule representing the aging status of the recorded investment in loans by classes
90 days or more past due and still accruing	262	277
Home equity
Schedule representing the aging status of the recorded investment in loans by classes
90 days or more past due and still accruing	2,026	995
Originated Portfolio
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	68,611	51,633
Current	8,591,011	7,406,768
Total loans	8,659,622	7,458,401
90 days or more past due and still accruing	2,346	1,283
Originated Portfolio | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	34,446	29,928
Originated Portfolio | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	16,991	8,560
Originated Portfolio | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	17,174	13,145
Originated Portfolio | Commercial
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	19,590	18,904
Current	2,164,693	1,882,622
Total loans	2,184,283	1,901,526
90 days or more past due and still accruing	58	11
Originated Portfolio | Commercial | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	6,578	10,421
Originated Portfolio | Commercial | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	5,408	4,842
Originated Portfolio | Commercial | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	7,604	3,641
Originated Portfolio | Commercial real estate
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	33,845	13,305
Current	2,371,927	1,908,494
Total loans	2,405,772	1,921,799
90 days or more past due and still accruing	262	277
Originated Portfolio | Commercial real estate | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	21,106	6,551
Originated Portfolio | Commercial real estate | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	7,518	1,589
Originated Portfolio | Commercial real estate | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	5,221	5,165
Originated Portfolio | Real estate construction and land development
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	0	3,220
Current	349,395	278,504
Total loans	349,395	281,724
90 days or more past due and still accruing	0	0
Originated Portfolio | Real estate construction and land development | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	0	2,721
Originated Portfolio | Real estate construction and land development | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	0	499
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
Total past due	0	0
Originated Portfolio | Residential mortgage
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	4,436	4,961
Current	1,679,114	1,470,381
Total loans	1,683,550	1,475,342
90 days or more past due and still accruing	0	0
Originated Portfolio | Residential mortgage | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	411	3,147
Originated Portfolio | Residential mortgage | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	2,607	62
Originated Portfolio | Residential mortgage | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	1,418	1,752
Originated Portfolio | Consumer installment
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	3,072	4,904
Current	1,426,016	1,277,684
Total loans	1,429,088	1,282,588
90 days or more past due and still accruing	0	0
Originated Portfolio | Consumer installment | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	2,553	3,991
Originated Portfolio | Consumer installment | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	363	675
Originated Portfolio | Consumer installment | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	156	238
Originated Portfolio | Home equity
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	7,668	6,339
Current	599,866	589,083
Total loans	607,534	595,422
90 days or more past due and still accruing	2,026	995
Originated Portfolio | Home equity | 30-59 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	3,798	3,097
Originated Portfolio | Home equity | 60-89 days past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	1,095	893
Originated Portfolio | Home equity | 90 days or more past due
Schedule representing the aging status of the recorded investment in loans by classes
Total past due	$ 2,775	$ 2,349

Loans - Impaired Loans by Class

Loans - Impaired Loans by Class (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	$ 71,241	$ 74,740
Unpaid Principal Balance	79,380	85,264
Related Valuation Allowance	7,547	9,392
Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	34,889	32,129
Unpaid Principal Balance	40,872	38,794
Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	106,130	106,869
Unpaid Principal Balance	120,252	124,058
Related Valuation Allowance	7,547	9,392
Commercial | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	28,623	28,925
Unpaid Principal Balance	31,419	33,209
Related Valuation Allowance	4,335	3,128
Commercial | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	7,677	7,435
Unpaid Principal Balance	9,761	11,153
Commercial | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	36,300	36,360
Unpaid Principal Balance	41,180	44,362
Related Valuation Allowance	4,335	3,128
Commercial real estate | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	20,209	21,318
Unpaid Principal Balance	25,552	27,558
Related Valuation Allowance	1,334	2,102
Commercial real estate | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	21,512	20,588
Unpaid Principal Balance	25,411	23,535
Commercial real estate | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	41,721	41,906
Unpaid Principal Balance	50,963	51,093
Related Valuation Allowance	1,334	2,102
Real estate construction and land development | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	189	177
Unpaid Principal Balance	189	177
Related Valuation Allowance	4	4
Real estate construction and land development | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	56	80
Unpaid Principal Balance	56	80
Real estate construction and land development | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	245	257
Unpaid Principal Balance	245	257
Related Valuation Allowance	4	4
Residential mortgage | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	16,711	20,864
Unpaid Principal Balance	16,711	20,864
Related Valuation Allowance	724	3,528
Residential mortgage | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,386	3,252
Unpaid Principal Balance	4,386	3,252
Residential mortgage | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	21,097	24,116
Unpaid Principal Balance	21,097	24,116
Related Valuation Allowance	724	3,528
Consumer installment | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	851	879
Unpaid Principal Balance	851	879
Related Valuation Allowance	88	240
Consumer installment | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	851	879
Unpaid Principal Balance	851	879
Related Valuation Allowance	88	240
Home equity | Impaired loans with a valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	4,658	2,577
Unpaid Principal Balance	4,658	2,577
Related Valuation Allowance	1,062	390
Home equity | Impaired loans with no valuation allowance
Financing Receivable, Impaired [Line Items]
Recorded Investment	1,258	774
Unpaid Principal Balance	1,258	774
Home equity | Total Impaired Loans
Financing Receivable, Impaired [Line Items]
Recorded Investment	5,916	3,351
Unpaid Principal Balance	5,916	3,351
Related Valuation Allowance	$ 1,062	$ 390

Loans - Impaired Loans (Details

Loans - Impaired Loans (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Average recorded investment
Impaired loans with a valuation allowance	$ 64,609	$ 28,176	$ 66,383	$ 33,654
Impaired loans with no related valuation allowance	42,184	86,400	39,969	86,167
Total impaired loans	106,793	114,576	106,352	119,821
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	491	333	1,176	666
Impaired loans with no related valuation allowance	162	624	304	1,287
Total impaired loans	653	957	1,480	1,953
Commercial
Average recorded investment
Impaired loans with a valuation allowance	24,493	3,867	25,103	7,209
Impaired loans with no related valuation allowance	11,010	32,502	10,153	31,952
Total impaired loans	35,503	36,369	35,256	39,161
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	201	0	425	0
Impaired loans with no related valuation allowance	48	310	78	587
Total impaired loans	249	310	503	587
Commercial real estate
Average recorded investment
Impaired loans with a valuation allowance	19,026	3,360	19,530	5,476
Impaired loans with no related valuation allowance	25,183	45,679	24,329	45,708
Total impaired loans	44,209	49,039	43,859	51,184
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	202	0	405	0
Impaired loans with no related valuation allowance	99	312	203	692
Total impaired loans	301	312	608	692
Real estate construction and land development
Average recorded investment
Impaired loans with a valuation allowance	141	0	151	0
Impaired loans with no related valuation allowance	106	860	93	889
Total impaired loans	247	860	244	889
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	3	0	5	0
Impaired loans with no related valuation allowance	0	2	0	8
Total impaired loans	3	2	5	8
Residential mortgage
Average recorded investment
Impaired loans with a valuation allowance	16,243	20,949	16,821	20,969
Impaired loans with no related valuation allowance	4,581	5,094	4,194	5,121
Total impaired loans	20,824	26,043	21,015	26,090
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	68	333	302	666
Impaired loans with no related valuation allowance	10	0	17	0
Total impaired loans	78	333	319	666
Consumer installment
Average recorded investment
Impaired loans with a valuation allowance	682	0	731	0
Impaired loans with no related valuation allowance	142	281	179	311
Total impaired loans	824	281	910	311
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	1	0	2	0
Impaired loans with no related valuation allowance	0	0	0	0
Total impaired loans	1	0	2	0
Home equity
Average recorded investment
Impaired loans with a valuation allowance	4,024	0	4,047	0
Impaired loans with no related valuation allowance	1,162	1,984	1,021	2,186
Total impaired loans	5,186	1,984	5,068	2,186
Interest income recognized while on impaired status
Impaired loans with a valuation allowance	16	0	37	0
Impaired loans with no related valuation allowance	5	0	6	0
Total impaired loans	$ 21	$ 0	$ 43	$ 0

Loans - Loan Modifications by C

Loans - Loan Modifications by Concession Type (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)loan	Jun. 30, 2016USD ($)loan	Jun. 30, 2017USD ($)loan	Jun. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 1,211	$ 6,093	$ 3,682	$ 11,116
Total number of loans (in loan) | loan	23	37	35	55
Pre-modification recorded investment	$ 1,258	$ 6,093	$ 3,793	$ 11,116
Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	497	4,172	1,213	9,158
Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	592	171	1,768	208
Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	122	1,750	701	1,750
Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 738	$ 5,603	$ 2,990	$ 10,422
Total number of loans (in loan) | loan	10	23	18	34
Pre-modification recorded investment	$ 758	$ 5,603	$ 3,019	$ 10,422
Commercial loan portfolio | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	285	3,853	782	8,672
Commercial loan portfolio | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	331	0	1,507	0
Commercial loan portfolio | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	122	1,750	701	1,750
Commercial loan portfolio | Commercial
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 551	$ 4,149	$ 2,281	$ 7,981
Total number of loans (in loan) | loan	7	21	12	28
Pre-modification recorded investment	$ 564	$ 4,149	$ 2,303	$ 7,981
Commercial loan portfolio | Commercial | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	285	2,399	335	6,231
Commercial loan portfolio | Commercial | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	266	0	1,367	0
Commercial loan portfolio | Commercial | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	1,750	579	1,750
Commercial loan portfolio | Commercial real estate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 187	$ 1,454	$ 709	$ 2,441
Total number of loans (in loan) | loan	3	2	6	6
Pre-modification recorded investment	$ 194	$ 1,454	$ 716	$ 2,441
Commercial loan portfolio | Commercial real estate | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	1,454	447	2,441
Commercial loan portfolio | Commercial real estate | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	65	0	140	0
Commercial loan portfolio | Commercial real estate | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	122	0	122	0
Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 473	$ 490	$ 692	$ 694
Total number of loans (in loan) | loan	13	14	17	21
Pre-modification recorded investment	$ 500	$ 490	$ 774	$ 694
Consumer loan portfolio | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	212	319	431	486
Consumer loan portfolio | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	261	171	261	208
Consumer loan portfolio | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Residential mortgage
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 298	$ 174	$ 396	$ 279
Total number of loans (in loan) | loan	5	2	6	3
Pre-modification recorded investment	$ 316	$ 174	$ 414	$ 279
Consumer loan portfolio | Residential mortgage | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	37	174	135	279
Consumer loan portfolio | Residential mortgage | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	261	0	261	0
Consumer loan portfolio | Residential mortgage | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Consumer installment
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 22	$ 47	$ 32	$ 80
Total number of loans (in loan) | loan	4	8	6	12
Pre-modification recorded investment	$ 24	$ 47	$ 35	$ 80
Consumer loan portfolio | Consumer installment | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	22	47	32	80
Consumer loan portfolio | Consumer installment | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Consumer installment | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	0	0	0
Consumer loan portfolio | Home equity
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 153	$ 269	$ 264	$ 335
Total number of loans (in loan) | loan	4	4	5	6
Pre-modification recorded investment	$ 160	$ 269	$ 325	$ 335
Consumer loan portfolio | Home equity | Principal deferral
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	153	98	264	127
Consumer loan portfolio | Home equity | Interest rate
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	0	171	0	208
Consumer loan portfolio | Home equity | Forbearance agreement
Financing Receivable, Modifications [Line Items]
Post-modification recorded investment	$ 0	$ 0	$ 0	$ 0

Loans - Summary of TDRs (Detail

Loans - Summary of TDRs (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Financing Receivable, Modifications [Line Items]
Total TDRs	$ 80,941	$ 93,066
Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	61,010	70,785
Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	19,931	22,281
Accruing TDRs
Financing Receivable, Modifications [Line Items]
Total TDRs	55,236	62,535
Accruing TDRs | Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	39,714	45,388
Accruing TDRs | Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	15,522	17,147
Nonaccrual TDRs
Financing Receivable, Modifications [Line Items]
Total TDRs	25,705	30,531
Nonaccrual TDRs | Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	21,296	25,397
Nonaccrual TDRs | Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Total TDRs	$ 4,409	$ 5,134

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, 2017USD ($)loan	Jun. 30, 2016USD ($)loan	Jun. 30, 2017USD ($)loan	Jun. 30, 2016USD ($)loan
Financing Receivable, Modifications [Line Items]
Number of loans (in loan) | loan	5	2	10	4
Principal balance | $	$ 1,055	$ 788	$ 1,780	$ 1,721
Commercial loan portfolio
Financing Receivable, Modifications [Line Items]
Number of loans (in loan) | loan	2	1	5	2
Principal balance | $	$ 997	$ 788	$ 1,617	$ 1,721
Consumer loan portfolio
Financing Receivable, Modifications [Line Items]
Number of loans (in loan) | loan	3	1	5	2
Principal balance | $	$ 58	$ 0	$ 163	$ 0

Loans - Allowance for Loan Loss

Loans - Allowance for Loan Losses (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	$ 78,774	$ 70,318	$ 78,268	$ 73,328
Provision for loan losses	6,229	3,000	10,279	4,500
Charge-offs	(2,304)	(3,620)	(7,878)	(9,078)
Recoveries	1,098	1,808	3,128	2,756
Ending balance	83,797	71,506	83,797	71,506
Allowance for loan losses
Loans individually evaluated for impairment					$ 7,547	$ 9,392
Loans collectively evaluated for impairment					76,250	68,876
Loans acquired with deteriorated credit quality					0	0
Total allowance for loan losses	78,774	70,318	78,268	73,328	83,797	78,268
Recorded investment (loan balance)
Loans individually evaluated for impairment					106,130	106,869
Loans collectively evaluated for impairment					8,553,492	7,351,532
Loans acquired with deteriorated credit quality					5,007,750	5,532,378
Total loans					13,667,372	12,990,779
Commercial loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	54,315	44,668	51,201	47,234
Provision for loan losses	4,084	900	8,476	1,900
Charge-offs	(726)	(2,542)	(3,417)	(6,438)
Recoveries	282	1,202	1,695	1,532
Ending balance	57,955	44,228	57,955	44,228
Allowance for loan losses
Loans individually evaluated for impairment					5,673	5,234
Loans collectively evaluated for impairment					52,282	45,967
Loans acquired with deteriorated credit quality					0	0
Total allowance for loan losses	54,315	44,668	51,201	47,234	57,955	51,201
Recorded investment (loan balance)
Loans individually evaluated for impairment					78,266	78,523
Loans collectively evaluated for impairment					4,861,184	4,026,526
Loans acquired with deteriorated credit quality					3,191,712	3,489,163
Total loans					8,131,162	7,594,212
Consumer loan portfolio
Schedule of allowance and recorded investment related to financing receivables segregated by portfolio segment
Beginning balance	24,459	25,650	27,067	26,094
Provision for loan losses	2,145	2,100	1,803	2,600
Charge-offs	(1,578)	(1,078)	(4,461)	(2,640)
Recoveries	816	606	1,433	1,224
Ending balance	25,842	27,278	25,842	27,278
Allowance for loan losses
Loans individually evaluated for impairment					1,874	4,158
Loans collectively evaluated for impairment					23,968	22,909
Loans acquired with deteriorated credit quality					0	0
Total allowance for loan losses	$ 24,459	$ 25,650	$ 27,067	$ 26,094	25,842	27,067
Recorded investment (loan balance)
Loans individually evaluated for impairment					27,864	28,346
Loans collectively evaluated for impairment					3,692,308	3,325,006
Loans acquired with deteriorated credit quality					1,816,038	2,043,215
Total loans					$ 5,536,210	$ 5,396,567

Other Real Estate Owned and R76

Other Real Estate Owned and Repossessed Assets - Rollforward Tables (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Changes in other real estate owned
Balance at the beginning of the period	$ 16,812	$ 9,716
Other additions	3,776	2,155
Net payments received	(202)	(85)
Disposals	(5,976)	(3,230)
Write-downs	(773)	(230)
Balance at the end of the period	13,637	8,326
Changes in repossessed assets
Balance at the beginning of the period	375	219
Other additions	2,556	1,215
Net payments received	0	(764)
Disposals	(1,986)	(556)
Write-downs	0	0
Balance at the end of the period	$ 945	$ 114

Other Real Estate Owned and R77

Other Real Estate Owned and Repossessed Assets - Textual (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Other Real Estate [Abstract]
Other real estate owned and repossessed assets acquired in accordance with ASU 2014-04	$ 0.9
Residential mortgage loans in process of foreclosure	$ 4.6	$ 7.3

Other Real Estate Owned and R78

Other Real Estate Owned and Repossessed Assets - Income and Expense (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Income and expenses related to other real estate owned
Net gain (loss) on sale	$ 768	$ 1,320	$ 1,815	$ 2,042
Write-downs	(504)	(63)	(773)	(230)
Net operating expenses	(710)	(260)	(1,218)	(412)
Total	(446)	997	(176)	1,400
Income and expenses related to repossessed assets
Net gain (loss) on sale	(93)	708	(171)	700
Write-downs	0	0	0	0
Net operating expenses	(3)	1	(6)	(3)
Total	$ (96)	$ 709	$ (177)	$ 697

Goodwill (Details)

Goodwill (Details) - USD ($)	Aug. 31, 2016	Jun. 30, 2017	Dec. 31, 2016
Goodwill [Line Items]
Goodwill		$ 1,133,534,000	$ 1,133,534,000
Goodwill impairment		$ 0
Talmer
Goodwill [Line Items]
Goodwill acquired during period	$ 846,667,000

Loan Servicing Rights - LSRs Ac

Loan Servicing Rights - LSRs Activity (Details) - USD ($) $ in Thousands		3 Months Ended	6 Months Ended
		Jun. 30, 2017	Jun. 30, 2017	Dec. 31, 2016
Loan Servicing Rights
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]			$ 3,659
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period		$ 64,604	$ 48,085
Transfers based on new accounting policy election			15,891
Additions from loans sold with servicing retained		2,384	4,137
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off		(664)	(1,270)
Changes in estimates of fair value		(1,802)	(2,321)
Fair value, end of period		64,522	64,522
Principal balance of loans serviced for others that have servicing capitalized		7,215,253	7,215,253
Commercial Real Estate
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period		320	344
Transfers based on new accounting policy election			0
Additions from loans sold with servicing retained		188	188
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off		(22)	(46)
Changes in estimates of fair value		0	0
Fair value, end of period		486	486
Principal balance of loans serviced for others that have servicing capitalized		47,349	47,349
Mortgage
Activity for loan servicing rights and the related fair value changes
Fair value, beginning of period		64,284	47,741
Transfers based on new accounting policy election			15,891
Additions from loans sold with servicing retained		2,196	3,949
Changes in fair value due to:
Reductions from pay-offs, pay downs and run-off		(642)	(1,224)
Changes in estimates of fair value		(1,802)	(2,321)
Fair value, end of period		64,036	64,036
Principal balance of loans serviced for others that have servicing capitalized		$ 7,167,904	$ 7,167,904
Retained earnings
Loan Servicing Rights
Cumulative effect adjustment of change in accounting policy, net of tax impact	[1]			$ 3,659
[1]	Refer to Note 1, Basis of Presentation and Significant Accounting Policies and Note 8, Loan Servicing Rights, for further details on the changes in accounting policy.

Loan Servicing Rights - Activit

Loan Servicing Rights - Activity for Capitalized LSRs (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Activity for Capitalized LSRs
Balance at beginning of period		$ 40,211
Amortization		(3,039)	$ (4,339)
Balance at end of period		$ 37,322
Loan servicing rights
Activity for Capitalized LSRs
Balance at beginning of period	$ 10,478		11,122
Additions	586		917
Amortization	(975)		(1,950)
Change in valuation allowance	(412)		(412)
Balance at end of period	$ 9,677		$ 9,677

Loan Servicing Rights - Assumpt

Loan Servicing Rights - Assumptions Used in Determining Fair Value (Details) - USD ($)	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Loan servicing rights
Loan servicing fee income	$ 4,500,000	$ 1,300,000	$ 9,100,000	$ 2,600,000
Mortgage
Loan servicing rights
Cost to service/per year			65
Ancillary income/per year			$ 31		$ 28
WA float range			1.20%
Mortgage | Weighted Average
Loan servicing rights
Discount rate			10.10%		10.10%
WA float range					1.00%
Mortgage | Minimum
Loan servicing rights
Prepayment speed			0.00%		0.00%
Cost to service/per year					$ 65
Mortgage | Maximum
Loan servicing rights
Prepayment speed			35.70%		99.80%
Cost to service/per year					$ 90

Other Intangible Assets - Intan

Other Intangible Assets - Intangible Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Total intangible assets	$ 37,322	$ 40,211
Core deposit intangible assets
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Gross original amount	59,143	59,143
Accumulated amortization	21,908	18,932
Total intangible assets	37,235	40,211
Non-compete intangible assets
Carrying amount, accumulated amortization and amortization expense of core deposit intangible assets
Total intangible assets	$ 87	$ 0

Other Intangible Assets - Textu

Other Intangible Assets - Textual (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets			$ (3,039)	$ (4,339)
Core deposit intangible assets
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ (1,500)	$ (1,100)	(3,000)	$ (2,200)
Estimated Future Amortization Expense, Fiscal Year Maturity [Abstract]
Remainder of 2017	3,000		3,000
2,018	5,700		5,700
2,019	5,400		5,400
2,020	4,900		4,900
2,021	4,500		4,500
2022 and thereafter	$ 13,800		$ 13,800

Derivative Instruments and Ba85

Derivative Instruments and Balance Sheet Offsetting - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2017
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative instruments
Amount of gain (loss) recognized in other noninterest income (Ineffective portion)	$ 0	$ 0

Derivative Instruments and Ba86

Derivative Instruments and Balance Sheet Offsetting - Notional Amount and Fair Value (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Derivative instruments
Notional Amount	$ 1,783,085	$ 853,594
Gross Derivative Assets	13,536	8,215
Gross Derivative Liabilities	11,496	6,359
Credit valuation adjustments for counterparty credit risk	538	99
Derivatives designated as hedging instruments:
Derivative instruments
Notional Amount	400,000	0
Gross Derivative Assets	224	0
Gross Derivative Liabilities	282	0
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative instruments
Notional Amount	400,000	0
Gross Derivative Assets	224	0
Gross Derivative Liabilities	282	0
Derivatives not designated as hedging | Total customer-initiated and mortgage banking derivatives
Derivative instruments
Notional Amount	1,383,085	853,594
Gross Derivative Assets	13,312	8,215
Gross Derivative Liabilities	11,214	6,359
Derivatives not designated as hedging | Customer-initiated derivatives
Derivative instruments
Notional Amount	1,055,917	600,598
Gross Derivative Assets	8,636	4,406
Gross Derivative Liabilities	9,152	4,141
Derivatives not designated as hedging | Forward contracts related to mortgage loans to be delivered for sale
Derivative instruments
Notional Amount	168,533	140,155
Gross Derivative Assets	617	635
Gross Derivative Liabilities	0	0
Derivatives not designated as hedging | Interest rate lock commitments
Derivative instruments
Notional Amount	120,095	76,034
Gross Derivative Assets	1,997	956
Gross Derivative Liabilities	0	0
Derivatives not designated as hedging | Power Equity CD
Derivative instruments
Notional Amount	38,540	36,807
Gross Derivative Assets	2,062	2,218
Gross Derivative Liabilities	$ 2,062	$ 2,218

Derivative Instruments and Ba87

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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Derivative instruments
Total gain (loss) recognized in income	$ 227	$ (84)	$ 242	$ (156)
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	959	(409)	(18)	(642)
Interest rate lock commitments | Net gain on sale of loans and other mortgage banking revenue
Derivative instruments
Total gain (loss) recognized in income	(181)	325	1,041	486
Customer-initiated derivatives | Other noninterest income
Derivative instruments
Total gain (loss) recognized in income	$ (551)	$ 0	$ (781)	$ 0

Derivative Instruments and Ba88

Derivative Instruments and Balance Sheet Offsetting - Net Gains (Losses) Recorded in Other Comprehensive Income and the Income Statement (Details) $ in Thousands	3 Months Ended	6 Months Ended
	Jun. 30, 2017USD ($)	Jun. 30, 2017USD ($)
Derivative instruments
Unrealized losses on interest rate swaps expected to be reclassified during next twelve months	$ 1,200	$ 1,200
Interest rate swaps | Derivatives designated as hedging instruments:
Derivative instruments
Amount of gain (loss) recognized in other comprehensive income (Effective portion)	(57)	(57)
Amount of gain (loss) reclassified from other comprehensive income to interest income or expense (Effective portion)	(409)	(409)
Amount of gain (loss) recognized in other noninterest income (Ineffective portion)	$ 0	$ 0

Derivative Instruments and Ba89

Derivative Instruments and Balance Sheet Offsetting - Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Offsetting derivative assets
Gross amounts recognized	$ 13,536	$ 8,215
Offsetting derivative liabilities
Gross amounts recognized	11,496	6,359
Interest rate swaps and customer-initiated derivatives
Offsetting derivative assets
Gross amounts recognized	8,838	4,405
Gross amounts offset in the statements of financial condition	0	0
Net amounts presented in the statements of financial position	8,838	4,405
Gross amounts not offset in the statements of financial position
Financial instruments	0	0
Collateral (received)/posted	0	0
Net Amount	8,838	4,405
Offsetting derivative liabilities
Gross amounts recognized	9,434	4,141
Gross amounts offset in the statements of financial condition	0	0
Net amounts presented in the statements of financial position	9,434	4,141
Gross amounts not offset in the statements of financial position
Financial instruments	0	0
Collateral (received)/posted	9,037	2,550
Net Amount	$ 397	$ 1,591

Investments in Qualified Affo90

Investments in Qualified Affordable Housing Projects, Federal Historic Projects and New Market Tax Credits (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
Expense related to qualified affordable housing projects	$ 800,000	$ 600,000	$ 1,500,000	$ 1,200,000
Remaining investment in qualified affordable housing projects	36,200,000		36,200,000		$ 29,500,000
Equity method investments	20,200,000		20,200,000		10,900,000
Remaining unfunded equity contributions	31,600,000		31,600,000		16,000,000
Impairment on tax credit projects	$ 0		$ 0		$ 0

Commitments, Contingencies an91

Commitments, Contingencies and Guarantees - Commitments (Details) - USD ($)	Jun. 30, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Potential losses from standby letters of credit	$ 0	$ 0
Undisbursed loan commitments	606,700,000	578,200,000
Probable credit losses	1,100,000	1,300,000
Financial and Performance Standby Letters of Credit
Loss Contingencies [Line Items]
Letters of credit outstanding	139,000,000	118,900,000
Commitments to Extend Credit
Loss Contingencies [Line Items]
Loan commitments under financial guarantee	$ 2,930,000,000	$ 2,700,000,000

Commitments, Contingencies an92

Commitments, Contingencies and Guarantees - Contingencies and Guarantees (Details) - Performance Guarantee - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Loss Contingencies [Line Items]
Recorded liability	$ 14.8	$ 16.9
Maximum potential amount of undiscounted future payments	14.2	16.1
Recourse liability	$ 0.2	$ 0.2

Commitments, Contingencies an93

Commitments, Contingencies and Guarantees - Warranties (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2016
Changes in the activity related to liability recorded in connection with representations and warranties
Reserve balance at beginning of period	$ 5,689	$ 3,825	$ 6,459	$ 4,048
Reserve reduction	(220)	0	(990)	(150)
Charge-offs	0	0	0	(73)
Ending reserve balance	5,469	3,825	5,469	3,825
Reserve balance
Liability for specific claims					$ 9	$ 730
General allowance					5,460	5,729
Total reserve balance	$ 5,689	$ 3,825	$ 6,459	$ 4,048	$ 5,469	$ 6,459

Borrowings - Other Borrowings (

Borrowings - Other Borrowings (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2017	Dec. 31, 2016
Long-term borrowings:
Amount	$ 435,852	$ 597,847
Weighted Average Rate	1.61%	1.63%
Total borrowings	$ 2,795,894	$ 1,765,894
Total short-term and long-term borrowings, Weighted Average Rate	1.03%	0.89%
FHLB advances: 0.96% - 1.40% fixed-rate notes | Minimum
Long-term borrowings:
Stated interest rate	0.96%
FHLB advances: 0.96% - 1.40% fixed-rate notes | Maximum
Long-term borrowings:
Stated interest rate	1.40%
FHLB Advances | FHLB advances: 0.92% - 7.44% fixed-rate notes due 2017 to 2020
Long-term borrowings:
Amount	$ 351,324	$ 438,538
Weighted Average Rate	1.30%	1.24%
Advances payable from Federal Home Loan Banks	$ 350,900	$ 437,800
Purchase accounting premiums	$ 500	700
FHLB Advances | FHLB advances: 0.92% - 7.44% fixed-rate notes due 2017 to 2020 | Minimum
Long-term borrowings:
Stated interest rate	0.92%
FHLB Advances | FHLB advances: 0.92% - 7.44% fixed-rate notes due 2017 to 2020 | Maximum
Long-term borrowings:
Stated interest rate	7.44%
Securities sold under agreements to repurchase
Long-term borrowings:
Amount	$ 9,000
Securities sold under agreements to repurchase | Securities sold under agreements to repurchase: 1.48% - 2.75% fixed-rate notes due in 2017
Long-term borrowings:
Amount	$ 9,048	$ 19,144
Weighted Average Rate	2.11%	3.17%
Purchase accounting premiums	$ 55	$ 100
Advances payable	$ 9,000	19,000
Securities sold under agreements to repurchase | Securities sold under agreements to repurchase: 1.48% - 2.75% fixed-rate notes due in 2017 | Minimum
Long-term borrowings:
Stated interest rate	1.48%
Securities sold under agreements to repurchase | Securities sold under agreements to repurchase: 1.48% - 2.75% fixed-rate notes due in 2017 | Maximum
Long-term borrowings:
Stated interest rate	2.75%
Line of credit
Long-term borrowings:
Amount	$ 59,854	$ 124,625
Weighted Average Rate	2.80%	2.52%
Spread on variable rate	1.75%
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	$ 11,354	$ 11,285
Weighted Average Rate	3.42%	3.14%
Advances payable	$ 15,000	$ 15,000
Purchase accounting discounts	$ 3,600	3,700
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	$ 4,272	$ 4,255
Weighted Average Rate	4.40%	4.25%
Spread on variable rate	3.25%
Advances payable	$ 5,000	$ 5,000
Purchase accounting discounts	700	700
Securities sold under agreements to repurchase
Short-term borrowings:
Amount	$ 310,042	$ 343,047
Weighted Average Rate	0.26%	0.16%
FHLB Advances | FHLB advances: 0.96% - 1.40% fixed-rate notes
Short-term borrowings:
Amount	$ 2,050,000	$ 825,000
Weighted Average Rate	1.02%	0.65%

Borrowings - Textual (Details)

Borrowings - Textual (Details) $ in Millions	Jun. 30, 2017USD ($)
Debt Disclosure [Abstract]
FHLB advances	$ 7,280
Additional borrowing available through FHLB	$ 50

Borrowings - Securities Sold Un

Borrowings - Securities Sold Under Agreements to Repurchase (Details) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Total	$ 435,852	$ 597,847
Amounts related to securities sold under agreements to repurchase not included in offsetting disclosure in Note 10	9,000
Securities sold under agreements to repurchase
Debt Instrument [Line Items]
Overnight and continuous	0
Up to 30 Days	0
30-90 Days	4,000
Greater than 90 Days	5,000
Total	$ 9,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Amount
Tax at statutory rate	$ 26,268	$ 12,707	$ 47,219	$ 24,384
Changes resulting from:
Tax-exempt interest income	(1,832)	(1,139)	(3,589)	(2,278)
State taxes, net of federal benefit	258	0	470	0
Change in valuation allowance	38	0	49	0
Bank-owned life insurance adjustments	(335)	(287)	(679)	(355)
Income tax credits, net	(1,102)	(834)	(1,797)	(1,631)
Tax benefits in excess of compensation costs on share-based payments	(248)	(68)	(6,382)	(411)
Other, net	(11)	153	2	580
Income tax expense	$ 23,036	$ 10,532	$ 35,293	$ 20,289
Rate
Tax at statutory rate	35.00%	35.00%	35.00%	35.00%
Changes resulting from:
Tax-exempt interest income	(2.40%)	(3.10%)	(2.70%)	(3.30%)
State taxes, net of federal benefit	0.30%	0.00%	0.40%	0.00%
Change in valuation allowance	0.00%	0.00%	0.00%	0.00%
Bank-owned life insurance adjustments	(0.40%)	(0.80%)	(0.50%)	(0.50%)
Income tax credits, net	(1.50%)	(2.30%)	(1.30%)	(2.30%)
Tax benefits in excess of compensation costs on share-based payments	(0.30%)	(0.20%)	(4.70%)	(0.60%)
Other, net	0.00%	0.40%	0.00%	0.80%
Effective federal income tax rate	30.70%	29.00%	26.20%	29.10%

Share-Based Compensation - Text

Share-Based Compensation - Textual (Details) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017USD ($)$ / sharesshares	Jun. 30, 2016USD ($)	Jun. 30, 2017USD ($)$ / sharesshares	Jun. 30, 2016USD ($)shares	Apr. 26, 2017shares
Share-based Compensation Plans (Textual)
Share-based compensation expense	$ 3,200	$ 1,000	$ 7,000	$ 1,800
Excess tax benefit from share-based compensation	$ 248	68	6,400	411
Cash received from option exercises			$ 1,000	700
Certain officers
Share-based Compensation Plans (Textual)
Corporation granted shares of common stock (in shares) | shares			13,500
Stock Incentive Plan of 2015
Share-based Compensation Plans (Textual)
Common stock available for future grants under share-based compensation plans (in shares) | shares	1,748,616		1,748,616
Stock Incentive Plan of 2017
Share-based Compensation Plans (Textual)
Number of shares authorized under stock incentive plan (in shares) | shares					1,750,000
Stock Incentive Plans After 2012
Share-based Compensation Plans (Textual)
Vesting period			5 years
Stock Incentive Plans Prior To 2013
Share-based Compensation Plans (Textual)
Vesting period			3 years
Stock options
Share-based Compensation Plans (Textual)
Stock options granted (in shares) | shares			126,691
Corporation granted options to purchase common stock (in shares) | shares			126,691
Stock option award vesting period			10 years
Outstanding in-the-money stock options, intrinsic value		$ 11,200		$ 11,200
Stock issued from exercises (in shares) | shares			511,144	47,758
Restricted stock units
Share-based Compensation Plans (Textual)
Corporation granted options to purchase restricted stock performance units (in shares) | shares			162,771
Stock issued from exercises (in shares) | shares			40,141
Unrecognized compensation expense	$ 11,500		$ 11,500
Unrecognized compensation expense, period for recognition			3 years 2 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			6 years 10 months
Weighted-average remaining contractual terms for exercisable stock options			5 years 8 months
Outstanding in-the-money stock options, intrinsic value	24,600		$ 24,600
Exercisable in-the-money stock options, intrinsic value	$ 20,700		$ 20,700
Closing price of common stock (dollars per share) | $ / shares	$ 48.41		$ 48.41
Unrecognized compensation expense	$ 3,000		$ 3,000
Unrecognized compensation expense, period for recognition			4 years 1 month
Restricted stock awards
Share-based Compensation Plans (Textual)
Unrecognized compensation expense	$ 2,700		$ 2,700
Unrecognized compensation expense, period for recognition			1 year 15 days

Share-Based Compensation - Stoc

Share-Based Compensation - Stock Option Activity (Details)	6 Months Ended
	Jun. 30, 2017$ / sharesshares
Non-Vested Stock Options Outstanding, Weighted- Average Grant Date Fair Value Per Share
Granted (dollars per share)	$ 10.05
Stock Options
Non-Vested Stock Options Outstanding, Number of Options
Beginning balance (in shares) | shares	407,939
Granted (in shares) | shares	126,691
Vested (in shares) | shares	(81,584)
Forfeited/expired (in shares) | shares	(10,337)
Ending balance (in shares) | shares	442,709
Non-Vested Stock Options Outstanding, Weighted- Average Grant Date Fair Value Per Share
Beginning balance (dollars per share)	$ 6.15
Granted (dollars per share)	10.05
Vested (dollars per share)	6.15
Forfeited/expired (dollars per share)	7.42
Ending balance (dollars per share)	$ 7.24
Stock Options Outstanding, Number of Options
Beginning balance (in shares) | shares	2,453,395
Granted (in shares) | shares	126,691
Exercised (in shares) | shares	(1,256,355)
Forfeited/expired (in shares) | shares	(10,337)
Ending balance (in shares) | shares	1,313,394
Weighted- Average Exercise Price Per Share
Beginning balance, Weighted Average Exercise Price (dollars per share)	$ 21.41
Granted, Weighted Average Exercise Price (dollars per share)	53.72
Exercised, Weighted Average Exercise Price (dollars per share)	16.19
Forfeited/expired, Weighted Average Exercise Price (dollars per share)	39.59
Ending balance, Weighted Average Exercise Price (dollars per share)	$ 29.39
Exercisable/vested, Number of Options (in shares) | shares	870,685
Exercisable/vested, Weighted Average Exercise Price (dollars per share)	$ 24.68
Stock Options | Non Vested
Weighted- Average Exercise Price Per Share
Beginning balance, Weighted Average Exercise Price (dollars per share)	32.81
Granted, Weighted Average Exercise Price (dollars per share)	53.72
Vested, Weighted Average Exercise Price (dollars per share)	32.81
Forfeited/expired, Weighted Average Exercise Price (dollars per share)	39.59
Ending balance, Weighted Average Exercise Price (dollars per share)	$ 38.64

Share-Based Compensation - Blac

Share-Based Compensation - Black-Scholes Pricing Model Assumptions (Details)	6 Months Ended
	Jun. 30, 2017$ / shares
Assumptions of Black-Scholes option pricing model
Expected dividend yield	3.32%
Risk-free interest rate	2.06%
Expected stock price volatility	26.90%
Expected life of options – in years	6 years
Weighted average fair value of options granted	$ 10.05

Share-Based Compensation - Rest

Share-Based Compensation - Restricted Stock Unit and Award Activity (Details)	6 Months Ended
	Jun. 30, 2017$ / sharesshares
Restricted Stock Units
Number of Units/Awards
Beginning balance (in shares) | shares	298,357
Granted (in shares) | shares	162,771
Converted into shares of common stock (in shares) | shares	(40,141)
Forfeited/expired (in shares) | shares	(3,529)
Ending balance (in shares) | shares	417,458
Weighted-average grant-date fair value
Beginning balance (dollars per share) | $ / shares	$ 32.81
Granted (dollars per share) | $ / shares	52.10
Converted into shares of common stock (dollars per share) | $ / shares	26.86
Forfeited (dollars per share) | $ / shares	47.27
Ending balance (dollars per share) | $ / shares	$ 40.79
Restricted Stock Awards
Number of Units/Awards
Beginning balance (in shares) | shares	365,891
Vested (in shares) | shares	(61,049)
Forfeited/expired (in shares) | shares	(3,657)
Ending balance (in shares) | shares	301,185
Weighted-average grant-date fair value
Beginning balance (dollars per share) | $ / shares	$ 46.23
Vested (dollars per share) | $ / shares	46.23
Forfeited (dollars per share) | $ / shares	46.23
Ending balance (dollars per share) | $ / shares	$ 46.23

Pension and Other Postretire102

Pension and Other Postretirement Benefit Plans - Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
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
Service cost	$ 234	$ 277	$ 467	$ 554
Interest cost	1,301	1,358	2,603	2,716
Expected return on plan assets	(2,217)	(2,140)	(4,434)	(4,281)
Amortization of unrecognized net (gain) loss	579	572	1,157	1,144
Net periodic benefit cost (income)	(103)	67	(207)	133
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	1	2	2	4
Interest cost	23	33	47	66
Amortization of prior service cost	0	29	0	58
Amortization of unrecognized net (gain) loss	(40)	(25)	(81)	(49)
Net periodic benefit cost (income)	$ (16)	$ 39	$ (32)	$ 79

Pension and Other Postretire103

Pension and Other Postretirement Benefit Plans - Textual (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Defined Benefit Plan Disclosure [Line Items]
Percentage of eligible pay contribution to certain employees			4.00%
Employer total contribution amount	$ 2,400,000	$ 1,400,000	$ 5,000,000
Corporation match as a percentage of the participants' elective deferrals			50.00%
Maximum percent of participants' base compensation matched			4.00%
Employer contributions to Pentegra DB Plan	0	0	$ 0
Defined Benefit Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Contribution to defined benefit pension plan	$ 0	$ 0	$ 0	$ 0
Defined Benefit Pension Plans | Qualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for pension plan expense			4.22%
Defined Benefit Pension Plans | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for pension plan expense			3.63%
Postretirement Benefit Plan | Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Discount rate for pension plan expense			3.79%
Corporation
Defined Benefit Plan Disclosure [Line Items]
Employer total contribution amount				$ 2,700,000

Regulatory Capital (Details)

Regulatory Capital (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 19, 2017	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Leverage Ratio
Cash dividends declared per common share (dollars per share)		$ 0.27	$ 0.26	$ 0.54	$ 0.52
Subsequent Event
Leverage Ratio
Cash dividends declared per common share (dollars per share)	$ 0.28
Chemical Bank
Regulatory Capital
Risk weighted assets		$ 14,300,000		$ 14,300,000		$ 13,360,000
Total Capital to Risk-Weighted Assets
Actual Amount		$ 1,608,525		$ 1,608,525		$ 1,608,980
Actual Ratio		11.20%		11.20%		12.00%
For Capital Adequacy Purposes Amount		$ 1,144,292		$ 1,144,292		$ 1,068,560
For Capital Adequacy Purposes Ratio		8.00%		8.00%		8.00%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 1,323,088		$ 1,323,088		$ 1,152,041
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio		9.30%		9.30%		8.60%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 1,430,365		$ 1,430,365		$ 1,335,700
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		$ 1,517,972		$ 1,517,972		$ 1,522,711
Actual Ratio		10.60%		10.60%		11.40%
For Capital Adequacy Purposes Amount		$ 858,219		$ 858,219		$ 801,420
For Capital Adequacy Purposes Ratio		6.00%		6.00%		6.00%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 1,037,015		$ 1,037,015		$ 884,901
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio		7.30%		7.30%		6.60%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 1,144,292		$ 1,144,292		$ 1,068,560
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		$ 1,517,972		$ 1,517,972		$ 1,522,711
Actual Ratio		10.60%		10.60%		11.40%
For Capital Adequacy Purposes Amount		$ 643,664		$ 643,664		$ 601,065
For Capital Adequacy Purposes Ratio		4.50%		4.50%		4.50%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 822,460		$ 822,460		$ 684,546
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio		5.80%		5.80%		5.10%
To Be Well Capitalized Under Prompt Corrective Action Provisions Amount		$ 929,737		$ 929,737		$ 868,205
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio		6.50%		6.50%		6.50%
Leverage Ratio
Actual Amount		$ 1,517,972		$ 1,517,972		$ 1,522,711
Actual Ratio		8.90%		8.90%		9.50%
For Capital Adequacy Purposes Amount		$ 682,224		$ 682,224		$ 641,457
For Capital Adequacy Purposes Ratio		4.00%		4.00%		4.00%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 682,224		$ 682,224		$ 641,457
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		$ 852,780		$ 852,780		$ 801,822
To Be Well Capitalized Under Prompt Corrective Action Provisions Ratio		5.00%		5.00%		5.00%
Corporation
Regulatory Capital
Risk weighted assets		$ 14,350,000		$ 14,350,000		$ 13,420,000
Total Capital to Risk-Weighted Assets
Actual Amount		$ 1,598,217		$ 1,598,217		$ 1,543,018
Actual Ratio		11.10%		11.10%		11.50%
For Capital Adequacy Purposes Amount		$ 1,147,806		$ 1,147,806		$ 1,073,431
For Capital Adequacy Purposes Ratio		8.00%		8.00%		8.00%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 1,327,151		$ 1,327,151		$ 1,157,293
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio		9.30%		9.30%		8.60%
Tier 1 Capital to Risk-Weighted Assets
Actual Amount		$ 1,492,038		$ 1,492,038		$ 1,441,209
Actual Ratio		10.40%		10.40%		10.70%
For Capital Adequacy Purposes Amount		$ 860,855		$ 860,855		$ 805,073
For Capital Adequacy Purposes Ratio		6.00%		6.00%		6.00%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 1,040,199		$ 1,040,199		$ 888,935
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio		7.30%		7.30%		6.60%
Common Equity Tier 1 Capital to Risk-Weighted Assets
Actual Amount		$ 1,492,038		$ 1,492,038		$ 1,441,209
Actual Ratio		10.40%		10.40%		10.70%
For Capital Adequacy Purposes Amount		$ 645,641		$ 645,641		$ 603,805
For Capital Adequacy Purposes Ratio		4.50%		4.50%		4.50%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 824,986		$ 824,986		$ 687,667
For Capital Adequacy Purposes Plus Capital Conservation Buffer Ratio		5.80%		5.80%		5.10%
Leverage Ratio
Actual Amount		$ 1,492,038		$ 1,492,038		$ 1,441,209
Actual Ratio		8.70%		8.70%		9.00%
For Capital Adequacy Purposes Amount		$ 683,677		$ 683,677		$ 643,603
For Capital Adequacy Purposes Ratio		4.00%		4.00%		4.00%
For Capital Adequacy Purposes Plus Capital Conservation Buffer Amount		$ 683,677		$ 683,677		$ 643,603
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, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net income	$ 52,014	$ 25,775	$ 99,618	$ 49,380
Net income allocated to participating securities	219	0	446	0
Net income allocated to common shareholders	$ 51,795	$ 25,775	$ 99,172	$ 49,380
Weighted average common shares - issued (in shares)	71,122,000	38,258,000	71,046,000	38,228,000
Average unvested restricted share awards (in shares)	(303,000)	0	(321,000)	0
Weighted average common shares outstanding - basic (in shares)	70,819,000	38,258,000	70,725,000	38,228,000
Effect of dilutive securities
Weighted average common stock equivalents (in shares)	624,000	342,000	704,000	332,000
Weighted average common shares outstanding - diluted (in shares)	71,443,000	38,600,000	71,429,000	38,560,000
EPS available to common shareholders
Basic earnings per common share (dollars per share)	$ 0.73	$ 0.67	$ 1.41	$ 1.29
Diluted earnings per common share (dollars per share)	0.73	0.67	1.39	1.28
Average stock valuation (dollars per share)	$ 47.78	$ 37.80	$ 49.78	$ 35.55
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)	125,782	0	90,537	0

Accumulated Other Comprehens106

Accumulated Other Comprehensive Loss - Changes in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance			$ 2,581,526	$ 1,015,974
Other comprehensive income before reclassifications	$ 3,127	$ 1,379	4,908	4,108
Amounts reclassified from accumulated other comprehensive income	709	(387)	999	(774)
Other comprehensive income, net of tax	3,836	992	5,907	3,334
Ending balance	2,639,442	1,050,299	2,639,442	1,050,299
Unrealized gains (losses) on securities available-for-sale, net of tax
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance	(12,420)	829	(14,142)	(1,888)
Other comprehensive income before reclassifications	3,593	1,379	5,374	4,108
Amounts reclassified from accumulated other comprehensive income	(50)	(12)	(109)	(24)
Other comprehensive income, net of tax	3,543	1,367	5,265	4,084
Ending balance	(8,877)	2,196	(8,877)	2,196
Defined Benefit Pension Plans
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance	(25,545)	(27,519)	(25,894)	(27,144)
Other comprehensive income before reclassifications	0	0	0	0
Amounts reclassified from accumulated other comprehensive income	350	(375)	699	(750)
Other comprehensive income, net of tax	350	(375)	699	(750)
Ending balance	(25,195)	(27,894)	(25,195)	(27,894)
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	0	0	0	0
Other comprehensive income before reclassifications	(466)	0	(466)	0
Amounts reclassified from accumulated other comprehensive income	409	0	409	0
Other comprehensive income, net of tax	(57)	0	(57)	0
Ending balance	(57)	0	(57)	0
Total
Components of accumulated other comprehensive income (loss), net of related tax benefit/expense
Beginning balance	(37,965)	(26,690)	(40,036)	(29,032)
Ending balance	$ (34,129)	$ (25,698)	$ (34,129)	$ (25,698)

Accumulated Other Comprehens107

Accumulated Other Comprehensive Loss - Reclassifications (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of investment securities	$ 77	$ 18	$ 167	$ 37
Income tax (expense)/benefit	(23,036)	(10,532)	(35,293)	(20,289)
Net income	52,014	25,775	99,618	49,380
Interest on short-term borrowings (interest expense)	4,659	226	6,317	326
Gains and losses on available-for-sale securities | Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Gain on sale of investment securities	77	18	167	37
Income tax (expense)/benefit	(27)	(6)	(58)	(13)
Net income	50	12	109	24
Amortization of defined benefit pension plan items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Salaries, wages and employee benefits (operating expenses)	(539)	577	(1,076)	1,154
Income tax (expense)/benefit	189	(202)	377	(404)
Net Income (loss)	(350)	375	(699)	750
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	(409)	0	(409)	0
Interest on short-term borrowings (interest expense)	$ 409	$ 0	$ 409	$ 0