S&T Bancorp (STBA) 10-Q 2 Nov 16 2016 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2016	Oct. 31, 2016
Document And Entity Information [Abstract]
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q3
Entity Registrant Name	S&T BANCORP INC
Entity Central Index Key	719,220
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		34,913,023

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
ASSETS
Cash and due from banks, including interest-bearing deposits of $68,961 and $41,639 at September 30, 2016 and December 31, 2015	$ 125,163	$ 99,399
Securities available-for-sale, at fair value	671,128	660,963
Loans held for sale	11,694	35,321
Portfolio loans, net of unearned income	5,418,234	5,027,612
Allowance for loan losses	(53,793)	(48,147)
Portfolio loans, net	5,364,441	4,979,465
Bank owned life insurance	71,523	70,175
Premises and equipment, net	47,122	49,127
Federal Home Loan Bank and other restricted stock, at cost	28,331	23,032
Goodwill	291,670	291,764
Other intangible assets, net	5,282	6,525
Other assets	101,851	102,583
Total Assets	6,718,205	6,318,354
LIABILITIES
Noninterest-bearing demand	1,232,469	1,227,766
Interest-bearing demand	657,326	616,188
Money market	764,125	605,184
Savings	1,026,234	1,061,265
Certificates of deposit	1,465,277	1,366,208
Total Deposits	5,145,431	4,876,611
Securities sold under repurchase agreements	40,949	62,086
Short-term borrowings	565,000	356,000
Long-term borrowings	15,303	117,043
Junior subordinated debt securities	45,619	45,619
Other liabilities	67,196	68,758
Total Liabilities	5,879,498	5,526,117
SHAREHOLDERS’ EQUITY
Common stock ($2.50 par value) Authorized—50,000,000 shares Issued—36,130,480 shares at September 30, 2016 and December 31, 2015 Outstanding—34,913,023 shares at September 30, 2016 and 34,810,374 shares at December 31, 2015	90,326	90,326
Additional paid-in capital	212,407	210,545
Retained earnings	575,192	544,228
Accumulated other comprehensive (loss) income	(5,643)	(16,457)
Treasury stock (1,217,457 shares at September 30, 2016 and 1,320,106 shares at December 31, 2015, at cost)	(33,575)	(36,405)
Total Shareholders’ Equity	838,707	792,237
Total Liabilities and Shareholders’ Equity	$ 6,718,205	$ 6,318,354

Consolidated Balance Sheets (U3

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Cash and due from banks, interest-bearing amounts	$ 68,961	$ 41,639
Common stock, par value (in dollars per share)	$ 2.50	$ 2.50
Common stock, shares authorized (in shares)	50,000,000	50,000,000
Common stock, shares issued (in shares)	36,130,480	36,130,480
Common stock, shares outstanding (in shares)	34,913,023	34,810,374
Treasury stock, shares (in shares)	1,217,457	1,320,106

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
INTEREST INCOME
Loans, including fees	$ 53,956	$ 49,578	$ 157,133	$ 138,438
Investment Securities:
Taxable	2,570	2,522	7,704	7,298
Tax-exempt	907	988	2,764	3,006
Dividends	375	581	1,077	1,453
Total Interest Income	57,808	53,669	168,678	150,195
INTEREST EXPENSE
Deposits	5,119	3,275	14,403	9,333
Borrowings and junior subordinated debt securities	1,234	798	3,474	2,196
Total Interest Expense	6,353	4,073	17,877	11,529
NET INTEREST INCOME	51,455	49,596	150,801	138,666
Provision for loan losses	2,516	3,206	12,379	6,473
Net Interest Income After Provision for Loan Losses	48,939	46,390	138,422	132,193
NONINTEREST INCOME
Securities (losses) gains, net	0	0	0	(34)
Service charges on deposit accounts	3,208	3,069	9,272	8,529
Debit and credit card fees	3,163	2,996	8,818	8,732
Wealth management fees	2,565	2,814	7,947	8,667
Insurance fees	1,208	1,332	4,187	4,374
Mortgage banking	1,077	698	2,185	2,006
Gain on sale of credit card portfolio	0	0	2,066	0
Other	2,227	1,572	7,238	5,674
Total Noninterest Income	13,448	12,481	41,713	37,948
NONINTEREST EXPENSE
Salaries and employee benefits	19,011	16,789	57,539	51,024
Data processing	2,129	2,454	6,964	7,329
Net occupancy	2,776	2,744	8,413	8,014
Furniture and equipment	1,932	1,653	5,580	4,461
Marketing	896	895	2,872	2,905
Professional services and legal	1,041	946	3,035	2,270
FDIC insurance	1,005	990	2,938	2,493
Other taxes	1,080	719	3,076	2,721
Merger related expenses	0	0	0	3,167
Other	4,569	6,639	17,190	18,515
Total Noninterest Expense	34,439	33,829	107,607	102,899
Income Before Taxes	27,948	25,042	72,528	67,242
Provision for income taxes	7,367	6,407	18,795	17,584
Net Income	$ 20,581	$ 18,635	$ 53,733	$ 49,658
Earnings per share—basic (in dollars per share)	$ 0.59	$ 0.54	$ 1.55	$ 1.48
Earnings per share—diluted (in dollars per share)	0.59	0.54	1.54	1.48
Dividends declared per share (in dollars per share)	$ 0.19	$ 0.18	$ 0.57	$ 0.54
Comprehensive Income	$ 19,686	$ 22,420	$ 64,547	$ 53,755

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity (Unaudited) - USD ($) $ in Thousands	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive (Loss)/Income	Treasury Stock
Balance at Dec. 31, 2014	$ 608,389	$ 77,993	$ 78,818	$ 504,060	$ (13,833)	$ (38,649)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	49,658			49,658
Other comprehensive income (loss), net of tax	4,097				4,097
Cash dividends declared	(17,886)			(17,886)
Common stock issued in acquisition	142,469	12,333	130,136
Treasury stock issued for restricted awards	(111)			(2,390)		2,279
Recognition of restricted stock compensation expense	1,266		1,266
Tax benefit from stock-based compensation	53		53
Issuance costs	(132)		(132)
Balance at Sep. 30, 2015	787,803	90,326	210,141	533,442	(9,736)	(36,370)
Balance at Dec. 31, 2015	792,237	90,326	210,545	544,228	(16,457)	(36,405)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	53,733			53,733
Other comprehensive income (loss), net of tax	10,814				10,814
Cash dividends declared	(19,824)			(19,824)
Treasury stock issued for restricted awards	(115)			(2,945)		2,830
Recognition of restricted stock compensation expense	1,862		1,862
Balance at Sep. 30, 2016	$ 838,707	$ 90,326	$ 212,407	$ 575,192	$ (5,643)	$ (33,575)

Consolidated Statements of Cha6

Consolidated Statements of Changes in Shareholders' Equity (Unaudited) (Parenthetical) - $ / shares	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
Statement of Stockholders' Equity [Abstract]
Dividends declared per share (in dollars per share)	$ 0.57	$ 0.54
Common stock issued in acquisition (in shares)		4,933,115
Treasury stock issued for restricted awards, net of forfeitures (in shares)	110,643	87,841
Forfeitures of restricted stock (in shares)	5,717	5,717

Consolidated Statements of Cash

Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
OPERATING ACTIVITIES
Net income	$ 53,733	$ 49,658
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	12,379	6,473
Provision for unfunded loan commitments	90	687
Depreciation, amortization and accretion	2,858	(6)
Net amortization of discounts and premiums on securities	2,816	2,682
Stock-based compensation expense	1,862	1,158
Securities losses, net	0	34
Tax benefit from stock-based compensation	0	(53)
Mortgage loans originated for sale	(75,505)	(81,966)
Proceeds from the sale of mortgage loans	77,009	71,872
Gain on the sale of mortgage loans, net	(1,154)	(730)
Gain on the sale of credit card portfolio	(2,066)	0
Pension plan curtailment gain	(1,017)	0
Net increase in interest receivable	(4,019)	(2,280)
Net increase (decrease) in interest payable	1,117	(637)
Net decrease in other assets	702	13,216
Net increase in other liabilities	3,586	1,531
Net Cash Provided by Operating Activities	72,391	61,639
INVESTING ACTIVITIES
Purchases of securities available-for-sale	(53,282)	(54,465)
Proceeds from maturities, prepayments and calls of securities available-for-sale	52,049	36,680
Proceeds from sales of securities available-for-sale	0	11,119
Net purchases of Federal Home Loan Bank stock	(5,298)	(3,535)
Net increase in loans	(406,370)	(276,282)
Proceeds from sale of loans not originated for resale	8,433	2,804
Purchases of premises and equipment	(2,744)	(3,737)
Proceeds from the sale of premises and equipment	20	264
Proceeds from the sale of credit card portfolio	25,019	0
Net cash paid in excess of cash acquired from bank merger	0	(16,347)
Net Cash Used in Investing Activities	(382,173)	(303,499)
FINANCING ACTIVITIES
Net increase in deposits	169,751	259,725
Net increase (decrease) in certificates of deposit	99,612	(12,399)
Net (decrease) increase in securities sold under repurchase agreements	(21,138)	12,366
Net increase (decrease) in short-term borrowings	209,000	(78,660)
Proceeds from long-term borrowings	0	100,000
Repayments of long-term borrowings	(101,740)	(1,829)
Repayment of junior subordinated debt	0	(13,500)
Treasury shares issued-net	(115)	(111)
Common stock issuance costs	0	(132)
Cash dividends paid to common shareholders	(19,824)	(17,886)
Tax benefit from stock-based compensation	0	53
Net Cash Provided by Financing Activities	335,546	247,627
Net increase in cash and cash equivalents	25,764	5,767
Cash and cash equivalents at beginning of period	99,399	109,580
Cash and Cash Equivalents at End of Period	125,163	115,347
Supplemental Disclosures
Loans transferred from held for sale to portfolio	1,540	0
Interest paid	16,761	11,853
Income taxes paid, net of refunds	17,974	15,675
Net assets acquired from bank merger, excluding cash and cash equivalents	0	43,433
Transfers of loans to other real estate owned	$ 581	$ 628

Basis of Presentation

Basis of Presentation	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Basis of Presentation	BASIS OF PRESENTATION Principles of Consolidation The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc., or S&T, and its wholly owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. Investments of 20 percent to 50 percent of the outstanding common stock of investees are accounted for using the equity method of accounting. Basis of Presentation The accompanying unaudited interim Consolidated Financial Statements of S&T have been prepared in accordance with generally accepted accounting principles, or GAAP, in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our annual report on Form 10-K for the year ended December 31, 2015 , filed with the Securities and Exchange Commission, or SEC, on February 23, 2016. In the opinion of management, the accompanying interim financial information reflects all adjustments, including normal recurring adjustments, necessary to present fairly our financial position and the results of operations for each of the interim periods presented. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year or any future period. Reclassification A mounts in prior period financial statements and footnotes are reclassified whenever necessary to conform to the current period presentation. Reclassifications had no effect on our results of operations or financial condition. Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates. Recently Adopted Accounting Standards Updates, or ASU Business Combinations - Simplifying the Accounting for Measurement Period Adjustments In September 2015, the Financial Accounting Standards Board, or FASB, issued ASU No. 2015-16, Business Combinations - Simplifying the Accounting for Measurement Period Adjustments (Topic 805). The amendments in this ASU No. 2015-16 eliminate the requirement to retrospectively adjust the financial statements for measurement-period adjustments as if they were known at the acquisition date, but are recognized in the reporting period in which they are determined. Additional disclosures are required about the impact on current-period income statement line items of adjustments that would have been recognized in prior periods if that information had been revised. The measurement period is a reasonable time period after the acquisition date when the acquirer may adjust the provisional amounts recognized for a business combination if the necessary information is not available by the end of the reporting period in which the acquisition occurs. The measurement periods cannot continue for more than one year from the acquisition date. The standard is effective for annual periods and interim periods beginning after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Intangibles - Goodwill and Other - Internal-Use Software: Customer's Accounting for Fees Paid in a Cloud Computing Arrangement In April 2015, the FASB issued ASU No. 2015-05, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement. The main provisions of ASU No. 2015-05 provide a basis for evaluating whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, then the arrangement should be accounted for as a service contract. The standard is effective for annual periods and interim periods beginning after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Interest - Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The standard is required to be adopted by public business entities in annual periods beginning on or after December 15, 2015. In September 2015, the FASB issued ASU No. 2015-15, Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements. ASU No. 2015-15 amends the SEC Content in Subtopic 835-30 by adding SEC paragraph 835-30-S35-1, Interest-Imputation of Interest Subsequent Measurement and paragraph 830-30-S45-1, Other Presentation Matters. These paragraphs were added because ASU No. 2015-03 issued in April 2015 does not address presentation or subsequent measurement of debt issuance costs related to "line-of-credit arrangements." The adoption of this ASU had no material impact on our results of operations or financial position. Consolidation: Amendments to the Consolidation Analysis In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis. The amendments in this ASU affect reporting entities that are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the revised consolidation model. Specifically, the amendments: 1. modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities, or VIEs, or voting interest entities; 2. eliminate the presumption that a general partner should consolidate a limited partnership; 3. affect the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships; and 4. provide a scope exception from consolidation guidance for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements that are similar to those in Rule 2A-7 of the Investment Company Act of 1940 for registered money market funds. The amendments in this ASU are effective for public business entities for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Income Statement - Extraordinary and Unusual Items: Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary In January 2015, the FASB issued ASU No. 2015-01, Income Statement - Extraordinary and Unusual Items (Subtopic 225-20): Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary. The amendments in this ASU No. 2015-01 eliminate from GAAP the concept of extraordinary items and eliminate the requirements for reporting entities to consider whether an underlying event or transaction is extraordinary. The presentation and disclosure guidance for items that are unusual in nature or occur infrequently will be retained and will be expanded to include items that are both unusual in nature and infrequently occurring. The standard is required to be adopted by public business entities in annual periods beginning on or after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Recently Issued Accounting Standards Updates not yet Adopted Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments. The main objective of this ASU is to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The amendments in this Update provide guidance on the following eight specific cash flow issues: Debt prepayment or debt extinguishments costs, Settlement of zero-coupon debt instruments, Contingent consideration payments made after a business combination, Proceeds from the settlement of insurance claims, Proceeds from the settlement of bank-owned life insurance (BOLI) policies, Distributions received from equity method investments, Beneficial interests in securitization transactions, and Separately identifiable cash flows and application of the predominance principle. This Update is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. Early adoption is permitted, provided that all of the amendments are adopted in the same period. We are evaluating the provisions of this ASU to determine the potential impact on our results of operations and financial position. Financial Instruments - Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments. The main objective of this ASU is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The amendments of this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The collective changes to the recognition and measurement accounting standards for financial instruments and their anticipated impact on the allowance for credit losses modeling have been universally referred to as the CECL, or current expected credit loss, model. This Update is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2019. Early adoption is permitted as of fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are evaluating the provisions of this ASU to determine the potential impact on our results of operations and financial position. Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The new revenue pronouncement creates a single source of revenue guidance for all companies in all industries and is more principles-based than current revenue guidance. The pronouncement provides a five-step model for a company to recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The five steps are: 1. identify the contract with the customer; 2. identify the separate performance obligations in the contract; 3. determine the transaction price; 4. allocate the transaction price to the separate performance obligations; and 5. recognize revenue when each performance obligation is satisfied. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date. This ASU defers the effective date of ASU No. 2014-09 for all entities by one year. In March 2016, the FASB issued ASU No. 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), as an amendment to ASU No. 2014-09 to improve Topic 606, Revenue from Contracts with Customers by reducing: 1. The potential for diversity in practice arising from inconsistent and application of the principal versus agent guidance, and 2. The cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In April 2016, the FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing, as an amendment to ASU No. 2014-09 to improve Topic 606, Revenue from Contracts with Customers, by reducing: 1. The potential for diversity in practice at initial application, and 2. The cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In May 2016, the FASB issued ASU No. 2016-12, Narrow-scope Improvements and Practical Expedients. The amendments in this ASU do not change the core principles of Topic 606, Revenue from Contracts with Customers. These amendments affect only the narrow aspects of Topic 606: 1. Collectibility Criterion, 2. Presentation of Sales Taxes and Other Similar Taxes Collected from Customers, 3. Noncash Consideration, 4. Contract Modifications at Transition, and 5. Completed Contracts at Transition. ASU 2014-09, including transition requirements for all amendments, is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. Early adoption is permitted as of the original effective date for interim and annual reporting periods in fiscal years beginning after December 15, 2016. We are evaluating the provisions of these ASUs to determine the potential impact to our results of operations and financial position. Stock Compensation - Improvements to Employee Share-Based Payment Accounting On March 31, 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting, which is intended to improve the accounting for share-based payment transactions as part of the FASB's simplification initiative. The ASU changes seven aspects of the accounting for share-based payment award transactions, including; 1. accounting for income taxes; 2. classification of excess tax benefits on the statement of cash flows; 3. forfeitures; 4. minimum statutory tax withholding requirements; 5. classification of employee taxes paid on the statement of cash flows when an employer withholds shares for tax-withholding purposes; 6. practical expedient -- expected term (nonpublic only); and 7. intrinsic value (nonpublic only). This ASU is effective for fiscal years beginning after December 15, 2016 and interim periods within those years for public business entities. Early adoption is permitted in any interim or annual period provided that the entire ASU is adopted. We do not expect that this ASU will have a material impact on our results of operations and financial position. Equity Method and Joint Ventures - Simplifying the Transition to the Equity Method of Accounting In March 2016, the FASB issued ASU No. 2016-07, Simplifying the Transition to the Equity Method of Accounting, which eliminates the requirement for an investor to retroactively apply the equity method when its increase in ownership interest (or degree of influence) in an investee triggers equity method accounting. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2016. The amendments should be applied prospectively upon their effective date to increases in the level of ownership interest or degree of influence that result in the adoption of the equity method. Earlier application is permitted. We do not expect that this ASU will have a material impact on our results of operations and financial position. Leases - Section A-Amendments to the FASB Accounting Standards Codification, Section B-Conforming Amendments Related to Leases and Section C-Background Information and Basis for Conclusions In February 2016, the FASB issued ASU No. 2016-02, Leases, which requires lessees to recognize a right-to-use asset and a lease obligation for all leases on the balance sheet. Lessor accounting remains substantially similar to current GAAP. ASU 2016-02 supersedes Topic 840, Leases. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2018. ASU 2016-02 mandates a modified retrospective transition method for all entities. Early adoption of this ASU is permitted. We anticipate that this ASU will impact our financial statements as it relates to the recognition of right-to-use assets and lease obligations on our Consolidated Balance Sheet. However, we do not expect that this ASU will have a material impact on our Consolidated Statement of Comprehensive Income. Accounting for Financial Instruments - Overall: Classification and Measurement In January 2016, the FASB issued ASU No. 2016-01, Accounting for Financial Instruments - Overall: Classification and Measurement (Subtopic 825-10). The amendments in this ASU No. 2016-01 address the following: 1. require equity investments to be measured at fair value with changes in fair value recognized in net income; 2. simplify the impairment assessment of equity investments without readily-determinable fair values by requiring a qualitative assessment to identify impairment; 3. eliminate the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; 4. require entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; 5. require separate presentation in other comprehensive income for the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; 6. require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; and 7. clarify that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity's other deferred tax assets. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2017. We anticipate that this ASU will have a significant impact on our financial statements and disclosures primarily as it relates to recognizing the fair value changes for equity securities in net income rather than an adjustment to equity through other comprehensive income.

Business Combinations

Business Combinations	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Business Combinations	On March 4, 2015, S&T acquired 100 percent of the voting shares of Integrity Bancshares, Inc., or Integrity, located in Camp Hill, Pennsylvania, through a tax-free reorganization transaction structured as a merger of Integrity with and into S&T, with S&T being the surviving entity. As a result of the Integrity merger, or the Merger, Integrity Bank, the wholly owned subsidiary bank of Integrity, became a separate wholly owned subsidiary bank of S&T. The merger of Integrity Bank into S&T Bank, with S&T Bank surviving the merger, and the related system conversion occurred on May 8, 2015. Integrity shareholders were entitled to elect to receive for each share of Integrity common stock either $52.50 in cash or 2.0627 shares of S&T common stock subject to allocation and proration procedures in the merger agreement. The total purchase price was approximately $172.0 million , which included $29.5 million of cash and 4,933,115 S&T common shares at a fair value of $28.88 per share. The fair value of $28.88 per share of S&T common stock was based on the March 4, 2015 closing price. The Merger was accounted for under the acquisition method of accounting and our Consolidated Financial Statements include all Integrity Bank transactions from March 4, 2015, until it was merged into S&T Bank on May 8, 2015. The assets acquired and liabilities assumed were recorded at their respective fair values and represent management’s estimates based on available information. Purchase accounting guidance allows for a reasonable period of time following an acquisition for the acquirer to obtain the information necessary to complete the accounting for a business combination. This period is known as the measurement period. At the end of the measurement period, $1.1 million in purchase accounting adjustments were recognized that increased goodwill. The measurement period adjustments primarily related to changes to provisional amounts, a $0.8 million reduction in the fair value of land and $0.3 million in deferred taxes. Goodwill of $115.9 million was calculated as the excess of the consideration exchanged over the fair value of the identifiable net assets acquired. The goodwill arising from the Merger consists largely of the synergies and economies of scale expected from combining the operations of S&T and Integrity. All of the goodwill was assigned to our Community Banking segment. The goodwill recognized will not be deductible for tax purposes. The following table summarizes total consideration, assets acquired and liabilities assumed from the Merger: (dollars in thousands) Consideration Paid Cash $ 29,510 Common stock 142,469 Fair Value of Total Consideration $ 171,979 Fair Value of Assets Acquired Cash and cash equivalents $ 13,163 Securities and other investments 11,502 Loans 788,687 Bank owned life insurance 15,974 Premises and equipment 10,855 Core deposit intangible 5,713 Other assets 19,088 Total Assets Acquired 864,982 Fair Value of Liabilities Assumed Deposits 722,308 Borrowings 82,286 Other liabilities 4,259 Total Liabilities Assumed 808,853 Total Fair Value of Identifiable Net Assets 56,129 Goodwill $ 115,850 Loans acquired in the Merger were recorded at fair value with no carryover of the related Allowance for Loan Losses, or ALL. Determining the fair value of the loans involves estimating the amount and timing of principal and interest cash flows expected to be collected on the loans and discounting those cash flows at a market rate of interest. The fair value of the loans acquired was $788.7 million net of a $14.8 million discount. The discount is accreted to interest income over the remaining contractual life of the loans. At March 4, 2015, acquired loans included $331.6 million of Commercial Real Estate, or CRE, $184.2 million of Commercial and Industrial, or C&I, $92.4 million of commercial construction, $116.9 million of residential mortgage, $25.6 million of home equity, $36.1 million of installment and other consumer and $1.9 million of consumer construction. Direct costs related to the Merger were expensed as incurred. No merger related expenses were recognized during the three month and nine month periods ended September 30, 2016 compared to no merger related expenses for the three month period and $3.2 million of Merger related expenses for the nine months ended September 30, 2015.

Earnings Per Share

Earnings Per Share	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Earnings Per Share	EARNINGS PER SHARE The following table reconciles the numerators and denominators of basic and diluted earnings per share for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except shares and per share data) 2016 2015 2016 2015 Numerator for Earnings per Share—Basic: Net income $ 20,581 $ 18,635 $ 53,733 $ 49,658 Less: Income allocated to participating shares 68 81 167 204 Net Income Allocated to Shareholders $ 20,513 $ 18,554 $ 53,566 $ 49,454 Numerator for Earnings per Share—Diluted: Net income $ 20,581 $ 18,635 $ 53,733 $ 49,658 Net Income Available to Shareholders $ 20,581 $ 18,635 $ 53,733 $ 49,658 Denominators for Earnings per Share: Weighted Average Shares Outstanding—Basic 34,687,487 34,660,007 34,674,453 33,527,549 Add: Potentially dilutive shares 81,018 32,985 72,724 33,980 Denominator for Treasury Stock Method—Diluted 34,768,505 34,692,992 34,747,177 33,561,529 Weighted Average Shares Outstanding—Basic 34,687,487 34,660,007 34,674,453 33,527,549 Add: Average participating shares outstanding 114,746 151,972 108,414 138,441 Denominator for Two-Class Method—Diluted 34,802,233 34,811,979 34,782,867 33,665,990 Earnings per share—basic $ 0.59 $ 0.54 $ 1.55 $ 1.48 Earnings per share—diluted $ 0.59 $ 0.54 $ 1.54 $ 1.48 Warrants considered anti-dilutive excluded from potentially dilutive shares - exercise price $31.53 per share, expire January 2019 517,012 517,012 517,012 517,012 Stock options considered anti-dilutive excluded from potentially dilutive shares - expired in December 2015 — 155,500 — 155,500 Restricted stock considered anti-dilutive excluded from potentially dilutive shares 146,695 118,987 134,983 104,461

Fair Value Measurement

Fair Value Measurement	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Fair Value Measurements	We use fair value measurements when recording and disclosing certain financial assets and liabilities. Securities available-for-sale, trading assets and derivative financial instruments are recorded at fair value on a recurring basis. Additionally, from time to time, we may be required to record other assets at fair value on a nonrecurring basis, such as loans held for sale, impaired loans, other real estate owned, or OREO, and other repossessed assets, mortgage servicing rights, or MSRs, and certain other assets. Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants at the measurement date. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets or liabilities; it is not a forced transaction. In determining fair value, we use various valuation approaches, including market, income and cost approaches. The fair value standard establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing an asset or liability, which is developed, based on market data we have obtained from independent sources. Unobservable inputs reflect our estimates of assumptions that market participants would use in pricing an asset or liability, which are developed based on the best information available in the circumstances. The fair value hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The fair value hierarchy is broken down into three levels based on the reliability of inputs as follows: Level 1: valuation is based upon unadjusted quoted market prices for identical instruments traded in active markets. Level 2: valuation is based upon quoted market prices for similar instruments traded in active markets, quoted market prices for identical or similar instruments traded in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by market data. Level 3: valuation is derived from other valuation methodologies, including discounted cash flow models and similar techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in determining fair value. A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our policy is to recognize transfers between any of the fair value hierarchy levels at the end of the reporting period in which the transfer occurred. The following are descriptions of the valuation methodologies that we use for financial instruments recorded at fair value on either a recurring or nonrecurring basis. Recurring Basis Securities Available-for-Sale Securities available-for-sale include both debt and equity securities. We obtain fair values for debt securities from a third-party pricing service which utilizes several sources for valuing fixed-income securities. We validate prices received from our pricing service through comparison to a secondary pricing service and broker quotes. We review the methodologies of the pricing service which provides us with a sufficient understanding of the valuation models, assumptions, inputs and pricing to reasonably measure the fair value of our debt securities. The market evaluation sources for debt securities include observable inputs rather than significant unobservable inputs and are classified as Level 2. The service provider utilizes pricing models that vary by asset class and include available trade, bid and other market information. Generally, the methodologies include broker quotes, proprietary models and vast descriptive terms and conditions databases, as well as extensive quality control programs. Marketable equity securities that have an active, quotable market are classified as Level 1. Marketable equity securities that are quotable, but are thinly traded or inactive, are classified as Level 2. Marketable equity securities that are not readily traded and do not have a quotable market are classified as Level 3. Trading Assets We use quoted market prices to determine the fair value of our trading assets. Our trading assets are held in a Rabbi Trust under a deferred compensation plan and are invested in readily quoted mutual funds. Accordingly, these assets are classified as Level 1. Derivative Financial Instruments We use derivative instruments, including interest rate swaps for commercial loans with our customers, interest rate lock commitments and the sale of mortgage loans in the secondary market. We calculate the fair value for derivatives using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. Each valuation considers the contractual terms of the derivative, including the period to maturity, and uses observable market based inputs, such as interest rate curves and implied volatilities. Accordingly, derivatives are classified as Level 2. We incorporate credit valuation adjustments into the valuation models to appropriately reflect both our own nonperformance risk and the respective counterparties' nonperformance risk in calculating fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements and collateral postings. Nonrecurring Basis Loans Held for Sale Loans held for sale consist of 1-4 family residential loans originated for sale in the secondary market and, from time to time, certain loans transferred from the loan portfolio to loans held for sale, all of which are carried at the lower of cost or fair value. The fair value of 1-4 family residential loans is based on the principal or most advantageous market currently offered for similar loans using observable market data. The fair value of the loans transferred from the loan portfolio is based on the amounts offered for these loans in currently pending sales transactions. Loans held for sale carried at fair value are classified as Level 3. Impaired Loans Impaired loans are carried at the lower of carrying value or fair value. Fair value is determined as the recorded investment balance less any specific reserve. We establish specific reserves based on the following three impairment methods: 1) the present value of expected future cash flows discounted at the loan’s original effective interest rate; 2) the loan’s observable market price; or 3) the fair value of the collateral less estimated selling costs when the loan is collateral dependent and we expect to liquidate the collateral. However, if repayment is expected to come from the operation of the collateral, rather than liquidation, then we do not consider estimated selling costs in determining the fair value of the collateral. Collateral values are generally based upon appraisals by approved, independent state certified appraisers. Appraisals may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or our knowledge of the borrower and the borrower’s business. Impaired loans carried at fair value are classified as Level 3. OREO and Other Repossessed Assets OREO and other repossessed assets obtained in partial or total satisfaction of a loan are recorded at the lower of recorded investment in the loan or fair value less cost to sell. Subsequent to foreclosure, these assets are carried at the lower of the amount recorded at acquisition date or fair value less cost to sell. Accordingly, it may be necessary to record nonrecurring fair value adjustments. Fair value, when recorded, is generally based upon appraisals by approved, independent state certified appraisers. Like impaired loans, appraisals on OREO may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or other information available to us. OREO and other repossessed assets carried at fair value are classified as Level 3. Mortgage Servicing Rights The fair value of MSRs is determined by calculating the present value of estimated future net servicing cash flows, considering expected mortgage loan prepayment rates, discount rates, servicing costs and other economic factors, which are determined based on current market conditions. The expected rate of mortgage loan prepayments is the most significant factor driving the value of MSRs. MSRs are considered impaired if the carrying value exceeds fair value. The valuation model includes significant unobservable inputs; therefore, MSRs are classified as Level 3. Other Assets We measure certain other assets at fair value on a nonrecurring basis. Fair value is based on the application of lower of cost or fair value accounting, or write-downs of individual assets. Valuation methodologies used to measure fair value are consistent with overall principles of fair value accounting and consistent with those described above. Financial Instruments In addition to financial instruments recorded at fair value in our financial statements, fair value accounting guidance requires disclosure of the fair value of all of an entity’s assets and liabilities that are considered financial instruments. The majority of our assets and liabilities are considered financial instruments. Many of these instruments lack an available trading market as characterized by a willing buyer and willing seller engaged in an exchange transaction. Also, it is our general practice and intent to hold our financial instruments to maturity and to not engage in trading or sales activities with respect to such financial instruments. For fair value disclosure purposes, we substantially utilize the fair value measurement criteria as required and explained above. In cases where quoted fair values are not available, we use present value methods to determine the fair value of our financial instruments. Cash and Cash Equivalents The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks, including interest-bearing deposits, approximate fair value. Loans The fair value of variable rate performing loans that may reprice frequently at short-term market rates is based on carrying values adjusted for credit risk. The fair value of variable rate performing loans that reprice at intervals of one year or longer, such as adjustable rate mortgage products, is estimated using discounted cash flow analyses that utilize interest rates currently being offered for similar loans and adjusted for credit risk. The fair value of fixed rate performing loans is estimated using a discounted cash flow analysis that utilizes interest rates currently being offered for similar loans and adjusted for credit risk. The fair value of nonperforming loans is the carrying value less any specific reserve on the loan if it is impaired. The carrying amount of accrued interest approximates fair value. Bank Owned Life Insurance Fair value approximates net cash surrender value of bank owned life insurance. Federal Home Loan Bank, or FHLB, and Other Restricted Stock It is not practical to determine the fair value of our FHLB and other restricted stock due to the restrictions placed on the transferability of these stocks; it is presented at carrying value. Deposits The fair values disclosed for deposits without defined maturities (e.g., noninterest and interest-bearing demand, money market and savings accounts) are by definition equal to the amounts payable on demand. The carrying amounts for variable rate, fixed-term time deposits approximate their fair values. Estimated fair values for fixed rate and other time deposits are based on discounted cash flow analysis using interest rates currently offered for time deposits with similar terms. The carrying amount of accrued interest approximates fair value. Short-Term Borrowings The carrying amounts of securities sold under repurchase agreements, or REPOs, and other short-term borrowings approximate their fair values. Long-Term Borrowings The fair values disclosed for fixed rate long-term borrowings are determined by discounting their contractual cash flows using current interest rates for long-term borrowings of similar remaining maturities. The carrying amounts of variable rate long-term borrowings approximate their fair values. Junior Subordinated Debt Securities The interest rate on the variable rate junior subordinated debt securities is reset quarterly; therefore, the carrying values approximate their fair values. Loan Commitments and Standby Letters of Credit Off-balance sheet financial instruments consist of commitments to extend credit and letters of credit. Except for interest rate lock commitments, estimates of the fair value of these off-balance sheet items are not made because of the short-term nature of these arrangements and the credit standing of the counterparties. Other Estimates of fair value are not made for items that are not defined as financial instruments, including such items as our core deposit intangibles and the value of our trust operations. Assets and Liabilities Recorded at Fair Value on a Recurring Basis The following tables present our assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at September 30, 2016 and December 31, 2015 . There were no transfers between Level 1 and Level 2 for items measured at fair value on a recurring basis during the periods presented. September 30, 2016 (dollars in thousands) Level 1 Level 2 Level 3 Total ASSETS Securities available-for-sale: U.S. Treasury securities $ — $ 15,056 $ — $ 15,056 Obligations of U.S. government corporations and agencies — 250,924 — 250,924 Collateralized mortgage obligations of U.S. government corporations and agencies — 137,460 — 137,460 Residential mortgage-backed securities of U.S. government corporations and agencies — 36,285 — 36,285 Commercial mortgage-backed securities of U.S. government corporations and agencies — 88,499 — 88,499 Obligations of states and political subdivisions — 132,536 — 132,536 Marketable equity securities — 10,368 — 10,368 Total securities available-for-sale — 671,128 — 671,128 Trading securities held in a Rabbi Trust 4,312 — — 4,312 Total securities 4,312 671,128 — 675,440 Derivative financial assets: Interest rate swap contracts - commercial loans — 15,255 — 15,255 Interest rate lock commitments - mortgage loans — 739 — 739 Total Assets $ 4,312 $ 687,122 $ — $ 691,434 LIABILITIES Derivative financial liabilities: Interest rate swap contracts - commercial loans $ — $ 15,202 $ — $ 15,202 Forward sale contracts - mortgage loans — 98 — 98 Total Liabilities $ — $ 15,300 $ — $ 15,300 December 31, 2015 (dollars in thousands) Level 1 Level 2 Level 3 Total ASSETS Securities available-for-sale: U.S. Treasury securities $ — $ 14,941 $ — $ 14,941 Obligations of U.S. government corporations and agencies — 263,303 — 263,303 Collateralized mortgage obligations of U.S. government corporations and agencies — 128,835 — 128,835 Residential mortgage-backed securities of U.S. government corporations and agencies — 40,125 — 40,125 Commercial mortgage-backed securities of U.S. government corporations and agencies — 69,204 — 69,204 Obligations of states and political subdivisions — 134,886 — 134,886 Marketable equity securities — 9,669 — 9,669 Total securities available-for-sale — 660,963 — 660,963 Trading securities held in a Rabbi Trust 4,021 — — 4,021 Total securities 4,021 660,963 — 664,984 Derivative financial assets: Interest rate swap contracts - commercial loans — 11,295 — 11,295 Interest rate lock commitments - mortgage loans — 261 — 261 Total Assets $ 4,021 $ 672,519 $ — $ 676,540 LIABILITIES Derivative financial liabilities: Interest rate swap contracts - commercial loans $ — $ 11,276 $ — $ 11,276 Forward sale contracts - mortgage loans — 5 — 5 Total Liabilities $ — $ 11,281 $ — $ 11,281 We may be required to measure certain assets and liabilities at fair value on a nonrecurring basis. Nonrecurring assets are recorded at the lower of cost or fair value in our financial statements. There were no liabilities measured at fair value on a nonrecurring basis at either September 30, 2016 or December 31, 2015 . The following table presents our assets that are measured at fair value on a nonrecurring basis by the fair value hierarchy level as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ASSETS (1) Impaired loans — — 9,000 9,000 — — 9,373 9,373 Other real estate owned — — 181 181 — — 158 158 Mortgage servicing rights — — 3,253 3,253 — — 3,396 3,396 Total Assets $ — $ — $ 12,434 $ 12,434 $ — $ — $ 12,927 $ 12,927 (1) This table presents only the nonrecurring items that are recorded at fair value in our financial statements. The carrying values and fair values of our financial instruments at September 30, 2016 and December 31, 2015 are presented in the following tables: Carrying Value (1) Fair Value Measurements at September 30, 2016 (dollars in thousands) Total Level 1 Level 2 Level 3 ASSETS Cash and due from banks, including interest-bearing deposits $ 125,163 $ 125,163 $ 125,163 $ — $ — Securities available-for-sale 671,128 671,128 — 671,128 — Loans held for sale 11,695 12,176 — — 12,176 Portfolio loans, net of unearned income 5,418,234 5,406,298 — — 5,406,298 Bank owned life insurance 71,523 71,523 — 71,523 — FHLB and other restricted stock 28,331 28,331 — — 28,331 Trading securities held in a Rabbi Trust 4,312 4,312 4,312 — — Mortgage servicing rights 3,252 3,253 — — 3,253 Interest rate swap contracts - commercial loans 15,255 15,255 — 15,255 — Interest rate lock commitments - mortgage loans 739 739 — 739 — LIABILITIES Deposits $ 5,145,431 $ 5,151,031 $ — $ — $ 5,151,031 Securities sold under repurchase agreements 40,949 40,949 — — 40,949 Short-term borrowings 565,000 565,000 — — 565,000 Long-term borrowings 15,303 16,111 — — 16,111 Junior subordinated debt securities 45,619 45,619 — — 45,619 Interest rate swap contracts - commercial loans 15,202 15,202 — 15,202 — Forward sale contracts - mortgage loans 98 98 — 98 — (1) As reported in the Consolidated Balance Sheets Carrying Value (1) Fair Value Measurements at December 31, 2015 (dollars in thousands) Total Level 1 Level 2 Level 3 ASSETS Cash and due from banks, including interest-bearing deposits $ 99,399 $ 99,399 $ 99,399 $ — $ — Securities available-for-sale 660,963 660,963 — 660,963 — Loans held for sale 35,321 35,500 — — 35,500 Portfolio loans, net of unearned income 5,027,612 5,001,004 — — 5,001,004 Bank owned life insurance 70,175 70,175 — 70,175 — FHLB and other restricted stock 23,032 23,032 — — 23,032 Trading securities held in a Rabbi Trust 4,021 4,021 4,021 — — Mortgage servicing rights 3,237 3,396 — — 3,396 Interest rate swap contracts - commercial loans 11,295 11,295 — 11,295 — Interest rate lock commitments - mortgage loans 261 261 — 261 — LIABILITIES Deposits $ 4,876,611 $ 4,881,718 $ — $ — $ 4,881,718 Securities sold under repurchase agreements 62,086 62,086 — — 62,086 Short-term borrowings 356,000 356,000 — — 356,000 Long-term borrowings 117,043 117,859 — — 117,859 Junior subordinated debt securities 45,619 45,619 — — 45,619 Interest rate swap contracts - commercial loans 11,276 11,276 — 11,276 — Forward sale contracts - mortgage loans 5 5 — 5 — (1) As reported in the Consolidated Balance Sheets

Securities Available-for-Sale

Securities Available-for-Sale	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Securities Available-for-Sale	The following tables present the amortized cost and fair value of available-for-sale securities as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. treasury securities $ 14,944 $ 112 $ — $ 15,056 $ 14,914 $ 27 $ — $ 14,941 Obligations of U.S. government corporations and agencies 246,259 4,665 — 250,924 262,045 1,825 (567 ) 263,303 Collateralized mortgage obligations of U.S. government corporations and agencies 134,675 2,785 — 137,460 128,458 693 (316 ) 128,835 Residential mortgage-backed securities of U.S. government corporations and agencies 34,685 1,600 — 36,285 39,185 1,091 (151 ) 40,125 Commercial mortgage-backed securities of U.S. government corporations and agencies 86,827 1,680 (8 ) 88,499 69,697 183 (676 ) 69,204 Obligations of states and political subdivisions 124,229 8,307 — 132,536 128,904 5,988 (6 ) 134,886 Debt Securities 641,619 19,149 (8 ) 660,760 643,203 9,807 (1,716 ) 651,294 Marketable equity securities 7,579 2,789 — 10,368 7,579 2,090 — 9,669 Total $ 649,198 $ 21,938 $ (8 ) $ 671,128 $ 650,782 $ 11,897 $ (1,716 ) $ 660,963 The following tables present the fair value and the age of gross unrealized losses by investment category as of the dates presented: September 30, 2016 Less Than 12 Months 12 Months or More Total (dollars in thousands) Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized U.S. Treasury securities — $ — $ — — $ — $ — — $ — $ — Obligations of U.S. government corporations and agencies — — — — — — — — — Collateralized mortgage obligations of U.S. government corporations and agencies — — — — — — — — — Residential mortgage-backed securities of U.S. government corporations and agencies — — — — — — — — — Commercial mortgage-backed securities of U.S. government corporations and agencies 1 7,841 (8 ) — — — 1 7,841 (8 ) Obligations of states and political subdivisions — — — — — — — — — Debt Securities 1 7,841 (8 ) — — — 1 7,841 (8 ) Marketable equity securities 1 71 — — — — 1 71 — Total Temporarily Impaired Securities 2 $ 7,912 $ (8 ) — $ — $ — 2 $ 7,912 $ (8 ) December 31, 2015 Less Than 12 Months 12 Months or More Total (dollars in thousands) Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized U.S. Treasury securities — $ — $ — — $ — $ — — $ — $ — Obligations of U.S. government corporations and agencies 10 88,584 (379 ) 2 14,542 (188 ) 12 103,126 (567 ) Collateralized mortgage obligations of U.S. government corporations and agencies 6 61,211 (316 ) — — — 6 61,211 (316 ) Residential mortgage-backed securities of U.S. government corporations and agencies 1 7,993 (151 ) — — — 1 7,993 (151 ) Commercial mortgage-backed securities of U.S. government corporations and agencies 5 50,839 (450 ) 1 9,472 (226 ) 6 60,311 (676 ) Obligations of states and political subdivisions 1 5,370 (6 ) — — — 1 5,370 (6 ) Debt Securities 23 213,997 (1,302 ) 3 24,014 (414 ) 26 238,011 (1,716 ) Marketable equity securities — — — — — — — — — Total Temporarily Impaired Securities 23 $ 213,997 $ (1,302 ) 3 $ 24,014 $ (414 ) 26 $ 238,011 $ (1,716 ) We do not believe any individual unrealized loss as of September 30, 2016 represents an other than temporary impairment. As of September 30, 2016 , one debt security and one marketable equity security were in an unrealized loss position compared to unrealized losses on 26 debt securities at December 31, 2015. There were no unrealized losses on marketable equity securities at December 31, 2015. These unrealized losses were primarily attributable to changes in interest rates and not related to the credit quality of these securities. All debt securities are determined to be investment grade and are paying principal and interest according to the contractual terms of the security. We do not intend to sell and it is not more likely than not that we will be required to sell any of the securities in an unrealized loss position before recovery of their amortized cost. The following table displays net unrealized gains and losses, net of tax on securities available for sale included in accumulated other comprehensive (loss)/income, for the periods presented: September 30, 2016 December 31, 2015 (dollars in thousands) Gross Unrealized Gains Gross Unrealized Losses Net Unrealized Gains/ (Losses) Gross Unrealized Gains Gross Unrealized Losses Net Unrealized Gains/ (Losses) Total unrealized gains/(losses) on securities available-for-sale $ 21,938 $ (8 ) $ 21,930 $ 11,897 $ (1,716 ) $ 10,181 Income tax expense/(benefit) 7,678 (3 ) 7,675 4,164 (601 ) 3,563 Net unrealized gains/(losses), net of tax included in accumulated other comprehensive income/(loss) $ 14,260 $ (5 ) $ 14,255 $ 7,733 $ (1,115 ) $ 6,618 The amortized cost and fair value of securities available-for-sale at September 30, 2016 by contractual maturity are included in the table below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2016 (dollars in thousands) Amortized Cost Fair Value Obligations of the U.S. Treasury, U.S. government corporations and agencies, and obligations of states and political subdivisions Due in one year or less $ 52,302 $ 52,439 Due after one year through five years 216,729 222,114 Due after five years through ten years 55,893 58,699 Due after ten years 60,508 65,264 385,432 398,516 Collateralized mortgage obligations of U.S. government corporations and agencies 134,675 137,460 Residential mortgage-backed securities of U.S. government corporations and agencies 34,685 36,285 Commercial mortgage-backed securities of U.S. government corporations and agencies 86,827 88,499 Debt Securities 641,619 660,760 Marketable equity securities 7,579 10,368 Total $ 649,198 $ 671,128 At September 30, 2016 and December 31, 2015 , securities with carrying values of $ 291.4 million and $278.4 million were pledged for various regulatory and legal requirements.

Loans and Loans Held for Sale

Loans and Loans Held for Sale	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Loans and Loans Held for Sale	Loans are presented net of unearned income of $4.6 million and $3.2 million at September 30, 2016 and December 31, 2015 and net of a discount related to purchase accounting fair value adjustments of $8.2 million and $10.9 million at September 30, 2016 and December 31, 2015 . The following table indicates the composition of loans as of the dates presented: (dollars in thousands) September 30, 2016 December 31, 2015 Commercial Commercial real estate $ 2,427,164 $ 2,166,603 Commercial and industrial 1,344,297 1,256,830 Commercial construction 402,124 413,444 Total Commercial Loans 4,173,585 3,836,877 Consumer Residential mortgage 692,574 639,372 Home equity 483,935 470,845 Installment and other consumer 62,288 73,939 Consumer construction 5,852 6,579 Total Consumer Loans 1,244,649 1,190,735 Total Portfolio Loans 5,418,234 5,027,612 Loans held for sale 11,694 35,321 Total Loans $ 5,429,928 $ 5,062,933 We attempt to limit our exposure to credit risk by diversifying our loan portfolio by segment, geography, collateral and industry and actively managing concentrations. When concentrations exist in certain segments, we monitor this risk by reviewing the relevant economic indicators and internal risk rating trends and through stress testing of the loans in these segments. Total commercial loans represented 77 percent of total portfolio loans at September 30, 2016 and 76 percent of total portfolio loans at December 31, 2015 . Within our commercial portfolio, the CRE and Commercial Construction portfolios combined comprised $2.8 billion or 68 percent of total commercial loans and 52 percent of total portfolio loans at September 30, 2016 and comprised of $2.6 billion or 67 percent of total commercial loans and 51 percent of total portfolio loans at December 31, 2015 . Further segmentation of the CRE and Commercial Construction portfolios by collateral type reveals no concentration in excess of seven percent of total loans at September 30, 2016 and December 31, 2015 . Our market area includes Pennsylvania and the contiguous states of Ohio, West Virginia, New York and Maryland. The majority of our commercial and consumer loans are made to businesses and individuals in this market area, resulting in a geographic concentration. We believe our knowledge and familiarity with customers and conditions locally outweighs this geographic concentration risk. The conditions of the local and regional economies are monitored closely through publicly available data as well as information supplied by our customers. Our CRE and Commercial Construction portfolios have out-of-market exposure of 5.4 percent of the combined portfolio and 2.8 percent of total loans at September 30, 2016 and 5.8 percent of the combined portfolio and 3.0 percent of total loans at December 31, 2015 . The decrease in loans held for sale of $23.6 million primarily related to the sale of our credit card portfolio, which was sold for $25.0 million and resulted in a $2.1 million gain for the nine months ended September 30, 2016 . Troubled debt restructurings, or TDRs, are loans where we, for economic or legal reasons related to a borrower’s financial difficulties, grant a concession to the borrower. We strive to identify borrowers with financial difficulty early and work with them to come to a mutual resolution to modify the terms of their loan before the loan goes nonaccrual. These modified terms generally include extensions of maturity dates at a stated interest rate lower than the current market rate for a new loan with similar risk characteristics, reductions in contractual interest rates or principal deferment. While unusual, there may be instances of principal forgiveness. These modifications are generally for longer term periods that would not be considered insignificant. Additionally, we classify loans where the debt obligation has been discharged through a Chapter 7 Bankruptcy and not reaffirmed as TDRs. We individually evaluate all substandard commercial loans that have experienced a forbearance or change in terms agreement, as well as all substandard consumer and residential mortgage loans that entered into an agreement to modify their existing loan to determine if they should be designated as TDRs. All TDRs are considered to be impaired loans and will be reported as impaired loans for the remaining life of the loan, unless the restructuring agreement specifies an interest rate equal to or greater than the rate that would be accepted at the time of the restructuring for a new loan with comparable risk and it is fully expected that the remaining principal and interest will be collected according to the restructured agreement. Further, all impaired loans are reported as nonaccrual loans unless the loan is a TDR that has met the requirements to be returned to accruing status. TDRs can be returned to accruing status if the ultimate collectability of all contractual amounts due, according to the restructured agreement, is not in doubt and there is a period of a minimum of six months of satisfactory payment performance by the borrower either immediately before or after the restructuring. The following table summarizes the restructured loans as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Performing TDRs Nonperforming TDRs Total TDRs Performing TDRs Nonperforming TDRs Total TDRs Commercial real estate $ 3,054 $ 866 $ 3,920 $ 6,822 $ 3,548 $ 10,370 Commercial and industrial 863 7,007 7,870 6,321 1,570 7,891 Commercial construction 3,460 992 4,452 5,013 1,265 6,278 Residential mortgage 2,453 5,248 7,701 2,590 665 3,255 Home equity 3,084 973 4,057 3,184 523 3,707 Installment and other consumer 22 9 31 25 88 113 Total $ 12,936 $ 15,095 $ 28,031 $ 23,955 $ 7,659 $ 31,614 There were no TDRs returned to accruing status during the three and nine months ended September 30, 2016 and there were six TDRs that returned to accruing status totaling $0.3 million during the three and nine months ended September 30, 2015 . The following tables present the restructured loans during the periods presented: Three Months Ended September 30, 2016 Three Months Ended September 30, 2015 (dollars in thousands) Number of Loans Pre-Modification Outstanding Recorded Investment ( 1) Post-Modification Outstanding Recorded Investment (1) Total Difference in Recorded Investment Number of Loans Pre-Modification Outstanding Recorded Investment (1) Post-Modification Outstanding Recorded Investment (1) Total Difference in Recorded Investment Commercial real estate Interest rate reduction 1 $ 250 $ 248 $ (2 ) — $ — $ — $ — Maturity date extension — — — — 1 264 260 (4 ) Commercial and industrial Maturity date extension 2 4,105 4,162 57 — — — — Commercial Construction Maturity date extension — — — — 2 813 812 (1 ) Residential mortgage Chapter 7 bankruptcy (2) 3 153 152 (1 ) 2 74 74 — Maturity date extension — — — — 1 180 180 — Maturity date extension and interest rate reduction 1 280 280 — — — — — Home equity Chapter 7 bankruptcy (2) 7 163 161 (2 ) 5 115 110 (5 ) Maturity date extension and interest rate reduction — — — — 2 138 138 — Installment and other consumer Chapter 7 bankruptcy (2) — — — — 1 9 4 (5 ) Total by Concession Type Chapter 7 bankruptcy (2) 10 $ 316 $ 313 $ (3 ) 8 $ 198 $ 188 $ (10 ) Interest rate reduction 1 250 248 (2 ) — — — — Maturity date extension and interest rate reduction 1 280 280 — 2 138 138 — Maturity date extension 2 4,105 4,162 57 4 1,257 1,252 (5 ) Total 14 $ 4,951 $ 5,003 $ 52 14 $ 1,593 $ 1,578 $ (15 ) (1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end. (2) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed. Nine Months Ended September 30, 2016 Nine Months Ended September 30, 2015 (dollars in thousands) Number of Pre-Modification (1) Post-Modification (1) Total Difference Number of Pre-Modification ( 1) Post-Modification (1) Total Difference Commercial real estate Principal deferral 1 $ 4,721 $ 2,270 $ (2,451 ) 2 $ 2,851 $ 1,841 $ (1,010 ) Chapter 7 bankruptcy (2) 1 709 681 (28 ) — — — — Interest rate reduction 1 250 248 (2 ) — — — — Maturity date extension — — — — 1 264 260 (4 ) Commercial and industrial Principal forgiveness — — — — 1 400 273 (127 ) Principal deferral 5 985 985 — 6 661 363 (298 ) Chapter 7 bankruptcy (2) — — — — 1 3 — (3 ) Maturity date extension 5 4,860 4,891 31 1 780 720 (60 ) Commercial Construction Principal deferral — — — — 1 104 — (104 ) Maturity date extension 5 1,357 1,302 (55 ) 2 813 812 (1 ) Residential mortgage Principal deferral 1 3,273 3,273 — — — — — Chapter 7 bankruptcy (2) 7 439 433 (6 ) 2 74 74 — Maturity date extension 1 483 483 — 1 180 180 — Maturity date extension and interest rate reduction 1 280 280 — 2 225 229 4 Home equity Principal deferral 1 47 46 (1 ) — — — — Chapter 7 bankruptcy (2) 16 481 470 (11 ) 17 428 389 (39 ) Maturity date extension and interest rate reduction 1 130 128 (2 ) 2 138 138 — Maturity date extension 4 274 272 (2 ) 1 71 70 (1 ) Installment and other consumer Chapter 7 bankruptcy (2) 2 16 13 (3 ) 1 9 4 (5 ) Total by Concession Type Principal forgiveness — $ — $ — $ — 1 $ 400 $ 273 $ (127 ) Principal deferral 8 9,026 6,574 (2,452 ) 9 3,616 2,204 (1,412 ) Chapter 7 bankruptcy (2) 26 1,645 1,597 (48 ) 21 514 467 (47 ) Interest rate reduction 1 250 248 (2 ) — Maturity date extension and interest rate reduction 2 410 408 (2 ) 4 363 367 4 Maturity date extension 15 6,974 6,948 (26 ) 6 2,108 2,042 (66 ) Total 52 $ 18,305 $ 15,775 $ (2,530 ) 41 $ 7,001 $ 5,353 $ (1,648 ) (1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end. (2) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed. For the three months ended September 30, 2016 , we modified 12 C&I loan totaling $16.9 million and one CRE loan totaling $ 1.9 million that were not considered to be TDRs. For the nine months ended September 30, 2016, we modified 15 C&I loans totaling $25.6 million and two CRE loans totaling $2.5 million that were not considered to be TDRs. The modifications were administrat ive extensions of maturity dates that were determined not to be a concession. As of September 30, 2016 , we have $0.3 million of commitments to lend additional funds on TDRs. Defaulted TDRs are defined as loans having a payment default of 90 days or more after the restructuring takes place. The following tables present a summary of TDRs which defaulted during the periods presented that had been restructured within the last 12 months prior to defaulting: Defaulted TDRs Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 (dollars in thousands) Number of Defaults Recorded Investment Number of Defaults Recorded Investment Number of Recorded Number of Recorded Commercial real estate — $ — — $ — — $ — — $ — Commercial and Industrial — — — — — — — — Commercial construction — — — — — — — — Residential mortgage — — — — — — 1 183 Home equity — — — — — — 3 124 Installment and other consumer — — — — — — — — Consumer construction — — — — — — — — Total — $ — — $ — — $ — 4 $ 307 The following table is a summary of nonperforming assets as of the dates presented: Nonperforming Assets (dollars in thousands) September 30, 2016 December 31, 2015 Nonperforming Assets Nonaccrual loans $ 25,398 $ 27,723 Nonaccrual TDRs 15,095 7,659 Total nonaccrual loans 40,493 35,382 OREO 512 354 Total Nonperforming Assets $ 41,005 $ 35,736

Allowance for Loan Losses

Allowance for Loan Losses	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Allowance for Loan Losses	We maintain an allowance for loan losses, or ALL, at a level determined to be adequate to absorb estimated probable credit losses inherent in the loan portfolio as of the balance sheet date. We develop and document a systematic ALL methodology based on the following portfolio segments: 1) CRE, 2) C&I, 3) Commercial Construction, 4) Consumer Real Estate and 5) Other Consumer. The following are key risks within each portfolio segment: CRE —Loans secured by commercial purpose real estate, including both owner occupied properties and investment properties, for various purposes such as hotels, strip malls and apartments. Operations of the individual projects as well as global cash flows of the debtors are the primary sources of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type as well as the business prospects of the lessee, if the project is not owner occupied. C&I —Loans made to operating companies or manufacturers for the purpose of production, operating capacity, accounts receivable, inventory or equipment financing. Cash flow from the operations of the company is the primary source of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the industry of the company. Collateral for these types of loans often does not have sufficient value in a distressed or liquidation scenario to satisfy the outstanding debt. Commercial Construction —Loans made to finance construction of buildings or other structures, as well as to finance the acquisition and development of raw land for various purposes. While the risk of these loans is generally confined to the construction period, if there are problems, the project may not be completed, and as such, may not provide sufficient cash flow on its own to service the debt or have sufficient value in a liquidation to cover the outstanding principal. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the type of project and the experience and resources of the developer. Consumer Real Estate —Loans secured by first and second liens such as home equity loans, home equity lines of credit and 1-4 family residential mortgages, including purchase money mortgages. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The state of the local housing market can also have a significant impact on this segment because low demand and/or declining home values can limit the ability of borrowers to sell a property and satisfy the debt. Other Consumer —Loans made to individuals that may be secured by assets other than 1-4 family residences, as well as unsecured loans. This segment includes auto loans, unsecured loans and lines and credit cards. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The value of the collateral, if there is any, is less likely to be a source of repayment due to less certain collateral values. We further assess risk within each portfolio segment by pooling loans with similar risk characteristics. For the commercial loan classes, the most important indicator of risk is the internally assigned risk rating, including pass, special mention and substandard. Consumer loans are pooled by type of collateral, lien position and loan to value, or LTV, ratio for Consumer Real Estate loans. Historical loss rates are applied to these loan pools to determine the reserve for loans collectively evaluated for impairment. The ALL methodology for groups of loans collectively evaluated for impairment is comprised of both a quantitative and qualitative analysis. A key assumption in the quantitative component of the reserve is the loss emergence period, or LEP. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is confirmed. Another key assumption is the look-back period, or LBP, which represents the historical data period utilized to calculate loss rates. Management monitors various credit quality indicators for both the commercial and consumer loan portfolios, including delinquency, nonperforming status and changes in risk ratings on a monthly basis. The following tables present the age analysis of past due loans segregated by class of loans as of the dates presented: September 30, 2016 (dollars in thousands) Current 30-59 Days Past Due 60-89 Days Past Due Nonaccrual Total Past Due Total Loans Commercial real estate $ 2,413,004 $ 3,286 $ 3,323 $ 7,551 $ 14,160 $ 2,427,164 Commercial and industrial 1,327,898 3,536 973 11,890 16,399 1,344,297 Commercial construction 394,812 456 203 6,653 7,312 402,124 Residential mortgage 679,237 585 1,352 11,400 13,337 692,574 Home equity 478,389 2,321 270 2,955 5,546 483,935 Installment and other consumer 61,954 205 85 44 334 62,288 Consumer construction 5,852 — — — — 5,852 Loans held for sale 11,694 — — — — 11,694 Total $ 5,372,840 $ 10,389 $ 6,206 $ 40,493 $ 57,088 $ 5,429,928 December 31, 2015 (dollars in thousands) Current 30-59 Days Past Due 60-89 Days Past Due Nonaccrual Total Past Due Total Loans Commercial real estate $ 2,145,655 $ 11,602 $ 627 $ 8,719 $ 20,948 $ 2,166,603 Commercial and industrial 1,244,802 2,453 296 9,279 12,028 1,256,830 Commercial construction 401,084 3,517 90 8,753 12,360 413,444 Residential mortgage 631,085 1,728 930 5,629 8,287 639,372 Home equity 465,055 2,365 523 2,902 5,790 470,845 Installment and other consumer 73,486 242 111 100 453 73,939 Consumer construction 6,579 — — — — 6,579 Loans held for sale 35,179 94 48 — 142 35,321 Total $ 5,002,925 $ 22,001 $ 2,625 $ 35,382 $ 60,008 $ 5,062,933 We continually monitor the commercial loan portfolio through an internal risk rating system. Loan risk ratings are assigned based upon the creditworthiness of the borrower and are reviewed on an ongoing basis according to our internal policies. Loans within the pass rating generally have a lower risk of loss than loans risk rated as special mention or substandard. Our risk ratings are consistent with regulatory guidance and are as follows: Pass —The loan is currently performing and is of high quality. Special Mention —A special mention loan has potential weaknesses that warrant management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects or in the strength of our credit position at some future date. Economic and market conditions, beyond the borrower’s control, may in the future necessitate this classification. Substandard —A substandard loan is not adequately protected by the net worth and/or paying capacity of the borrower or by the collateral pledged, if any. Substandard loans have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. These loans are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected. The following tables present the recorded investment in commercial loan classes by internally assigned risk ratings as of the dates presented: September 30, 2016 (dollars in thousands) Commercial Real Estate % of Total Commercial and Industrial % of Total Commercial Construction % of Total Total % of Total Pass $ 2,346,848 96.7 % $ 1,253,411 93.2 % $ 375,006 93.2 % $ 3,975,265 95.2 % Special mention 30,050 1.2 % 37,079 2.8 % 14,335 3.6 % 81,464 2.0 % Substandard 50,266 2.1 % 53,807 4.0 % 12,783 3.2 % 116,856 2.8 % Total $ 2,427,164 100.0 % $ 1,344,297 100.0 % $ 402,124 100.0 % $ 4,173,585 100.0 % December 31, 2015 (dollars in thousands) Commercial Real Estate % of Total Commercial and Industrial % of Total Commercial Construction % of Total Total % of Total Pass $ 2,094,851 96.7 % $ 1,182,685 94.1 % $ 375,808 90.9 % $ 3,653,344 95.2 % Special mention 19,938 0.9 % 43,896 3.5 % 19,846 4.8 % 83,680 2.2 % Substandard 51,814 2.4 % 30,249 2.4 % 17,790 4.3 % 99,853 2.6 % Total $ 2,166,603 100.0 % $ 1,256,830 100.0 % $ 413,444 100.0 % $ 3,836,877 100.0 % We monitor the delinquent status of the consumer portfolio on a monthly basis. Loans are considered nonperforming when interest and principal are 90 days or more past due or management has determined that a material deterioration in the borrower’s financial condition exists. The risk of loss is generally highest for nonperforming loans. The following tables present the recorded investment in consumer loan classes by performing and nonperforming status as of the dates presented: September 30, 2016 (dollars in thousands) Residential Mortgage % of Total Home Equity % of Total Installment and other consumer % of Total Consumer Construction % of Total Total % of Total Performing $ 681,174 98.4 % $ 480,980 99.4 % $ 62,244 99.9 % $ 5,852 100.0 % $ 1,230,250 98.8 % Nonperforming 11,400 1.6 % 2,955 0.6 % 44 0.1 % — — % 14,399 1.2 % Total $ 692,574 100.0 % $ 483,935 100.0 % $ 62,288 100.0 % $ 5,852 100.0 % $ 1,244,649 100.0 % December 31, 2015 (dollars in thousands) Residential Mortgage % of Total Home Equity % of Total Installment and other consumer % of Total Consumer Construction % of Total Total % of Total Performing $ 633,743 99.1 % $ 467,943 99.4 % $ 73,839 99.8 % $ 6,579 100.0 % $ 1,182,104 99.3 % Nonperforming 5,629 0.9 % 2,902 0.6 % 100 0.2 % — — % 8,631 0.7 % Total $ 639,372 100.0 % $ 470,845 100.0 % $ 73,939 100.0 % $ 6,579 100.0 % $ 1,190,735 100.0 % We individually evaluate all substandard and nonaccrual commercial loans greater than $0.5 million for impairment. Loans are considered to be impaired when based upon current information and events it is probable that we will be unable to collect all principal and interest payments due according to the original contractual terms of the loan agreement. All TDRs will be reported as an impaired loan for the remaining life of the loan, unless the restructuring agreement specifies an interest rate equal to or greater than the rate that would be accepted at the time of the restructuring for a new loan with comparable risk and it is expected that the remaining principal and interest will be fully collected according to the restructured agreement. For all TDRs, regardless of size, as well as all other impaired loans, we conduct further analysis to determine the probable loss and assign a specific reserve to the loan if deemed appropriate. The following tables summarize investments in loans considered to be impaired and related information on those impaired loans as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance Without a related allowance recorded: Commercial real estate $ 7,589 $ 7,818 $ — $ 12,661 $ 13,157 $ — Commercial and industrial 8,261 9,730 — 14,417 15,220 — Commercial construction 7,987 11,547 — 10,998 14,200 — Consumer real estate 11,731 12,434 — 6,845 7,521 — Other consumer 29 36 — 111 188 — Total without a Related Allowance Recorded 35,597 41,565 — 45,032 50,286 — With a related allowance recorded: Commercial real estate — — — — — — Commercial and industrial 2,433 2,433 2,206 — — — Commercial construction — — — 500 1,350 3 Consumer real estate 27 27 27 116 116 32 Other consumer 2 2 2 2 2 2 Total with a Related Allowance Recorded 2,462 2,462 2,235 618 1,468 37 Total: Commercial real estate 7,589 7,818 — 12,661 13,157 — Commercial and industrial 10,694 12,163 2,206 14,417 15,220 — Commercial construction 7,987 11,547 — 11,498 15,550 3 Consumer real estate 11,758 12,461 27 6,961 7,637 32 Other consumer 31 38 2 113 190 2 Total $ 38,059 $ 44,027 $ 2,235 $ 45,650 $ 51,754 $ 37 As of September 30, 2016 , we had $38.1 million of impaired loans which included $14.4 million of acquired loans from the Merger that experienced credit deterioration since the acquisition date. The following tables summarize investments in loans considered to be impaired and related information on those impaired loans for the periods presented: For the Three Months Ended September 30, 2016 September 30, 2015 (dollars in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Without a related allowance recorded: Commercial real estate $ 7,582 $ 38 $ 14,101 $ 352 Commercial and industrial 7,326 52 8,993 44 Commercial construction 8,039 49 11,034 67 Consumer real estate 11,686 159 6,829 92 Other consumer 32 — 183 — Total without a Related Allowance Recorded 34,665 298 41,140 555 With a related allowance recorded: Commercial real estate — — — — Commercial and industrial 2,437 37 1,977 7 Commercial construction — — — — Consumer real estate 28 — 119 2 Other consumer 2 — 2 — Total with a Related Allowance Recorded 2,467 37 2,098 9 Total: Commercial real estate 7,582 38 14,101 352 Commercial and industrial 9,763 89 10,970 51 Commercial construction 8,039 49 11,034 67 Consumer real estate 11,714 159 6,948 94 Other consumer 34 — 185 — Total $ 37,132 $ 335 $ 43,238 $ 564 For the Nine Months Ended September 30, 2016 September 30, 2015 (dollars in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Without a related allowance recorded: Commercial real estate $ 7,551 $ 106 $ 14,994 $ 731 Commercial and industrial 7,447 156 9,742 131 Commercial construction 8,498 143 8,920 200 Consumer real estate 11,831 400 6,856 279 Other consumer 38 1 119 1 Total without a Related Allowance Recorded 35,365 806 40,631 1,342 With a related allowance recorded: Commercial real estate — — — — Commercial and industrial 2,492 100 1,980 42 Commercial construction — — — — Consumer real estate 29 2 121 5 Other consumer 2 — 2 — Total with a Related Allowance Recorded 2,523 102 2,103 47 Total: Commercial real estate 7,551 106 14,994 731 Commercial and industrial 9,939 256 11,722 173 Commercial construction 8,498 143 8,920 200 Consumer real estate 11,860 402 6,977 284 Other consumer 40 1 121 1 Total $ 37,888 $ 908 $ 42,734 $ 1,389 The following tables detail activity in the ALL for the periods presented: Three Months Ended September 30, 2016 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 15,978 $ 14,771 $ 11,701 $ 8,418 $ 1,345 $ 52,213 Charge-offs (93 ) (414 ) (163 ) (369 ) (461 ) (1,500 ) Recoveries 264 169 17 44 70 564 Net (Charge-offs)/ Recoveries 171 (245 ) (146 ) (325 ) (391 ) (936 ) Provision for loan losses 4,244 (2,232 ) 1,356 (1,760 ) 908 2,516 Balance at End of Period $ 20,393 $ 12,294 $ 12,911 $ 6,333 $ 1,862 $ 53,793 Three Months Ended September 30, 2015 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 19,018 $ 13,308 $ 7,671 $ 7,027 $ 1,790 $ 48,814 Charge-offs (2,361 ) (1,121 ) (1,247 ) (445 ) (467 ) (5,641 ) Recoveries 2,896 272 129 132 99 3,528 Net (Charge-offs)/ Recoveries 535 (849 ) (1,118 ) (313 ) (368 ) (2,113 ) Provision for loan losses (2,575 ) 12 4,983 302 484 3,206 Balance at End of Period $ 16,978 $ 12,471 $ 11,536 $ 7,016 $ 1,906 $ 49,907 Nine Months Ended September 30, 2016 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 15,043 $ 10,853 $ 12,625 $ 8,400 $ 1,226 $ 48,147 Charge-offs (1,808 ) (3,244 ) (1,108 ) (891 ) (1,572 ) (8,623 ) Recoveries 662 589 20 342 277 1,890 Net (Charge-offs)/Recoveries (1,146 ) (2,655 ) (1,088 ) (549 ) (1,295 ) (6,733 ) Provision for loan losses 6,496 4,096 1,374 (1,518 ) 1,931 12,379 Balance at End of Period $ 20,393 $ 12,294 $ 12,911 $ 6,333 $ 1,862 $ 53,793 Nine Months Ended September 30, 2015 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 20,164 $ 13,668 $ 6,093 $ 6,333 $ 1,653 $ 47,911 Charge-offs (2,738 ) (2,819 ) (1,247 ) (997 ) (1,046 ) (8,847 ) Recoveries 3,072 475 132 379 312 4,370 Net (Charge-offs)/Recoveries 334 (2,344 ) (1,115 ) (618 ) (734 ) (4,477 ) Provision for loan losses (3,520 ) 1,147 6,558 1,301 987 6,473 Balance at End of Period $ 16,978 $ 12,471 $ 11,536 $ 7,016 $ 1,906 $ 49,907 The following tables present the ALL and recorded investments in loans by category as of the periods presented: September 30, 2016 Allowance for Loan Losses Portfolio Loans (dollars in thousands) Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Commercial real estate $ — $ 20,393 $ 20,393 $ 7,589 $ 2,419,575 $ 2,427,164 Commercial and industrial 2,206 10,088 12,294 10,694 1,333,603 1,344,297 Commercial construction — 12,911 12,911 7,987 394,137 402,124 Consumer real estate 27 6,306 6,333 11,758 1,170,603 1,182,361 Other consumer 2 1,860 1,862 31 62,257 62,288 Total $ 2,235 $ 51,558 $ 53,793 $ 38,059 $ 5,380,175 $ 5,418,234 December 31, 2015 Allowance for Loan Losses Portfolio Loans (dollars in thousands) Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Commercial real estate $ — $ 15,043 $ 15,043 $ 12,661 $ 2,153,942 $ 2,166,603 Commercial and industrial — 10,853 10,853 14,417 1,242,413 1,256,830 Commercial construction 3 12,622 12,625 11,498 401,946 413,444 Consumer real estate 32 8,368 8,400 6,961 1,109,835 1,116,796 Other consumer 2 1,224 1,226 113 73,826 73,939 Total $ 37 $ 48,110 $ 48,147 $ 45,650 $ 4,981,962 $ 5,027,612

Derivative Instruments and Hedg

Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Instruments and Hedging Activities	Interest Rate Swaps In accordance with applicable accounting guidance for derivatives and hedging, all derivatives are recognized as either assets or liabilities on the balance sheet at fair value. Interest rate swaps are contracts in which a series of interest rate flows (fixed and variable) are exchanged over a prescribed period. The notional amounts on which the interest payments are based are not exchanged. These derivative positions relate to transactions in which we enter into an interest rate swap with a commercial customer while at the same time entering into an offsetting interest rate swap with another financial institution. In connection with each transaction, we agree to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on the same notional amount at a fixed rate. At the same time, we agree to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows our customer to effectively convert a variable rate loan to a fixed rate loan with us receiving a variable rate. These agreements could have floors or caps on the contracted interest rates. Pursuant to our agreements with various financial institutions, we may receive collateral or may be required to post collateral based upon mark-to-market positions. Beyond unsecured threshold levels, collateral in the form of cash or securities may be made available to counterparties of interest rate swap transactions. Based upon our current positions and related future collateral requirements relating to them, we believe any effect on our cash flow or liquidity position to be immaterial. Derivatives contain an element of credit risk, the possibility that we will incur a loss because a counterparty, which may be a financial institution or a customer, fails to meet its contractual obligations. All derivative contracts with financial institutions may be executed only with counterparties approved by our Asset and Liability Committee, or ALCO, and derivatives with customers may only be executed with customers within credit exposure limits approved by our Senior Loan Committee. Interest rate swaps are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the estimated fair value of the derivatives are recorded in current earnings and included in other noninterest income in the Consolidated Statements of Net Income. Interest Rate Lock Commitments and Forward Sale Contracts In the normal course of business, we sell originated mortgage loans into the secondary mortgage loan market. We also offer interest rate lock commitments to potential borrowers. The commitments are generally for a period of 60 days and guarantee a specified interest rate for a loan if underwriting standards are met, but the commitment does not obligate the potential borrower to close on the loan. Accordingly, some commitments expire prior to becoming loans. We may encounter pricing risks if interest rates increase significantly before the loan can be closed and sold. We may utilize forward sale contracts in order to mitigate this pricing risk. Whenever a customer desires these products, a mortgage originator quotes a secondary market rate guaranteed for that day by the investor. The rate lock is executed between the mortgagee and us and in turn a forward sale contract may be executed between us and the investor. Both the rate lock commitment and the corresponding forward sale contract for each customer are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the estimated fair value of the derivatives during the commitment period are recorded in current earnings and included in mortgage banking in the Consolidated Statements of Net Income. The following table indicates the amounts representing the value of derivative assets and derivative liabilities as of the dates presented: Derivatives (included in Other Assets) Derivatives (included in Other Liabilities) (dollars in thousands) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Derivatives not Designated as Hedging Instruments: Interest Rate Swap Contracts- Commercial Loans Fair value $ 15,255 $ 11,295 $ 15,202 $ 11,276 Notional amount 264,655 245,595 264,655 245,595 Collateral posted — — 14,542 12,753 Interest Rate Lock Commitments- Mortgage Loans Fair value 739 261 — — Notional amount 21,699 9,894 — — Forward Sale Contracts- Mortgage Loans Fair value — — 98 5 Notional amount $ — $ — $ 16,892 $ 9,800 Presenting offsetting derivatives that are subject to legally enforceable netting arrangements with the same party is permitted. For example, we may have a derivative asset as well as a derivative liability with the same counterparty to a swap transaction and are permitted to offset the asset position and the liability position resulting in a net presentation. The following table indicates the gross amounts of commercial loan swap derivative assets and derivative liabilities, the amounts offset and the carrying values in the Consolidated Balance Sheets as of the dates presented: Derivatives (included in Other Assets) Derivatives (included in Other Liabilities) (dollars in thousands) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Derivatives not Designated as Hedging Instruments: Gross amounts recognized $ 15,255 $ 11,295 $ 15,202 $ 11,276 Gross amounts offset — — — — Net amounts presented in the Consolidated Balance Sheets 15,255 11,295 15,202 11,276 Gross amounts not offset (1) — — (14,542 ) (12,573 ) Net Amount $ 15,255 $ 11,295 $ 660 $ (1,297 ) (1) Amounts represent posted collateral. The following table indicates the gain or loss recognized in income on derivatives for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Derivatives not Designated as Hedging Instruments Interest rate swap contracts—commercial loans $ (87 ) $ 29 $ 34 $ 20 Interest rate lock commitments—mortgage loans 97 208 478 339 Forward sale contracts—mortgage loans 106 (143 ) (93 ) (69 ) Total Derivatives Gain $ 116 $ 94 $ 419 $ 290

Borrowings

Borrowings	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Borrowings	Short-term borrowings are for terms under one year and were comprised of REPOs and FHLB advances. All REPOs are overnight short-term investments and are not insured by the Federal Deposit Insurance Corporation. Securities pledged as collateral under these REPO financing arrangements cannot be sold or repledged by the secured party and are therefore accounted for as a secured borrowing. Mortgage-backed securities with a total carrying value of $47.4 million at September 30, 2016 and $67.0 million at December 31, 2015 were pledged as collateral for these secured transactions. The pledged securities are held in safekeeping at the Federal Reserve. Due to the overnight short-term nature of REPOs, potential risk due to a decline in the value of the pledged collateral is low. Collateral pledging requirements with REPOs are monitored daily. FHLB advances are for various terms and are secured by a blanket lien on residential mortgages and other real estate secured loans. Long-term borrowings are for original terms greater than or equal to one year and were comprised of FHLB advances, a capital lease and junior subordinated debt securities. Long-term FHLB advances are secured by the same loans as short-term FHLB advances. We had total long-term borrowings outstanding of $12.1 million at a fixed rate and $3.1 million at a variable rate at September 30, 2016 , excluding our capital lease of $0.1 million . On March 4, 2015 we assumed $13.5 million of junior subordinated debt in connection with the Merger. On March 5, 2015, we paid off $8.5 million and on June 18, 2015, we paid off the remaining $5.0 million . Information pertaining to borrowings is summarized in the table below as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Balance Weighted Average Rate Balance Weighted Average Rate Short-term borrowings Securities sold under repurchase agreements $ 40,949 0.01 % $ 62,086 0.01 % Short-term borrowings 565,000 0.60 % 356,000 0.52 % Total short-term borrowings 605,949 0.56 % 418,086 0.44 % Long-term borrowings Other long-term borrowings 15,303 2.91 % 117,043 0.81 % Junior subordinated debt securities 45,619 3.11 % 45,619 2.89 % Total long-term borrowings 60,922 3.06 % 162,662 1.39 % Total Borrowings $ 666,871 0.79 % $ 580,748 0.71 % We had total borrowings at September 30, 2016 and December 31, 2015 at the FHLB of Pittsburgh of $580.2 million and $473.0 million . The $580.2 million at September 30, 2016 consisted of $565.0 million in short-term borrowings and $15.2 million in long-term borrowings. Our maximum borrowing capacity with the FHLB of Pittsburgh was $2.2 billion at September 30, 2016 . Our remaining borrowing availability is $1.4 billion . We utilized $802.1 million of our borrowing capacity at September 30, 2016 consisting of $580.2 million for borrowings and $221.9 million for letters of credit to collateralize public funds.

Commitments and Contingencies

Commitments and Contingencies	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments In the normal course of business, we offer off-balance sheet credit arrangements to enable our customers to meet their financing objectives. These instruments involve, to varying degrees, elements of credit and interest rate risk in excess of the amount recognized in the financial statements. Our exposure to credit loss, in the event the customer does not satisfy the terms of the agreement, equals the contractual amount of the obligation less the value of any collateral. We apply the same credit policies in making commitments and standby letters of credit that are used for the underwriting of loans to customers. Commitments generally have fixed expiration dates, annual renewals or other termination clauses and may require payment of a fee. Because many of the commitments are expected to expire without being drawn upon, the total commitment amounts do not necessarily represent future cash requirements. Our allowance for unfunded commitments totaled $2.6 million at September 30, 2016 and $2.5 million at December 31, 2015 . The allowance for unfunded commitments is included in other liabilities in the Consolidated Balance Sheets. The allowance for unfunded commitments is determined using a similar methodology as our ALL methodology. The reserve is calculated by applying historical loss rates and qualitative adjustments to our unfunded commitments. Estimates of the fair value of these off-balance sheet items were not made because of the short-term nature of these arrangements and the credit standing of the counterparties. The following table sets forth our commitments and letters of credit as of the dates presented: (dollars in thousands) September 30, 2016 December 31, 2015 Commitments to extend credit $ 1,546,164 $ 1,619,854 Standby letters of credit 80,181 97,676 Total $ 1,626,345 $ 1,717,530 Litigation In the normal course of business, we are subject to various legal and administrative proceedings and claims. While any type of litigation contains a level of uncertainty, we believe that no outcome of any such proceedings or claims pending will have a material adverse effect on our consolidated financial position or results of operations.

Other Comprehensive Income

Other Comprehensive Income	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Other Comprehensive Income	The following table represents the change in components of other comprehensive income (loss) for the periods presented, net of tax effects. Three Months Ended September 30, 2016 Three Months Ended September 30, 2015 (dollars in thousands) Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Change in net unrealized gains/(losses) on securities available-for-sale $ (1,921 ) $ 672 $ (1,249 ) $ 5,177 $ (1,812 ) $ 3,365 Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income (1) — — — — — — Adjustment to funded status of employee benefit plans 544 (190 ) 354 647 (227 ) 420 Other Comprehensive Income/(Loss) $ (1,377 ) $ 482 $ (895 ) $ 5,824 $ (2,039 ) $ 3,785 (1) Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income/(loss) and have affected certain lines in the Consolidated Statements of Comprehensive Income as follows; the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income. Nine Months Ended September 30, 2016 Nine Months Ended September 30, 2015 (dollars in thousands) Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Change in net unrealized gains/(losses) on securities available-for-sale $ 11,748 $ (4,112 ) $ 7,636 $ 4,288 $ (1,501 ) $ 2,787 Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income (1) — — — 34 (12 ) 22 Adjustment to funded status of employee benefit plans 4,889 (1,711 ) 3,178 1,839 (551 ) 1,288 Other Comprehensive Income $ 16,637 $ (5,823 ) $ 10,814 $ 6,161 $ (2,064 ) $ 4,097 (1) Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.

Employee Benefits

Employee Benefits	9 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefits	Effective March 31, 2016, the qualified and nonqualified defined benefit plans were amended to freeze benefit accruals for all persons entitled to benefits under the plan. We recorded a curtailment gain in the first quarter of 2016 resulting from the amendment. The curtailment gain totaled $1.0 million and represented the unrecognized benefits associated with prior plan amendments that would have been amortized into income over the next seven years . The qualified plan was previously closed to new participants effective December 31, 2007. We will continue recording pension expense related to this plan, primarily representing interest costs on the accumulated benefit obligation and amortization of actuarial losses accumulated in the plan, as well as income from expected investment returns on pension assets. Prior to March 31, 2016, the accrued benefits were based on years of service and the employee’s compensation for the highest five consecutive years in the last ten years . Contributions were intended to provide for benefits attributed to employee service to date and for those benefits expected to be earned in the future. The expected long-term rate of return on plan assets is 7.50 percent . Effective January 1, 2015, the plan was amended to provide unmarried participants with the ability to name a beneficiary to receive a lump sum death benefit equal to 80 percent of the participant’s accrued benefit payable at normal retirement age, in the event the participant dies while employed by S&T. The following table summarizes the components of net periodic pension cost for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Components of Net Periodic Pension Cost Service cost—benefits earned during the period $ (6 ) $ 606 $ 469 $ 1,951 Interest cost on projected benefit obligation 1,099 1,120 3,200 3,319 Expected return on plan assets (1,444 ) (1,772 ) (4,337 ) (5,385 ) Amortization of prior service credit 29 (34 ) (41 ) (104 ) Recognized net actuarial loss 638 586 1,708 1,521 Net Periodic Pension Expense $ 316 $ 506 $ 999 $ 1,302

Segments

Segments	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Segments	We operate three reportable operating segments: Community Banking, Insurance and Wealth Management. • Our Community Banking segment offers services which include accepting time and demand deposits and originating commercial and consumer loans. • Our Insurance segment includes a full-service insurance agency offering commercial property and casualty insurance, group life and health coverage, employee benefit solutions and personal insurance lines. • Our Wealth Management segment offers discount brokerage services, services as executor and trustee under wills and deeds, guardian and custodian of employee benefits and other trust and brokerage services, as well as a registered investment advisor that manages private investment accounts for individuals and institutions. The following table represents total assets by reportable operating segment as of the dates presented: (dollars in thousands) September 30, 2016 December 31, 2015 Community Banking $ 6,706,383 $ 6,305,046 Insurance 8,050 9,619 Wealth Management 3,772 3,689 Total Assets $ 6,718,205 $ 6,318,354 The following tables provide financial information for our three operating segments for the three and nine month periods ended September 30, 2016 and 2015 . The financial results of the business segments include allocations for shared services based on an internal analysis that supports line of business and branch performance measurements. Shared services include expenses such as employee benefits, occupancy expense, computer support and other corporate overhead. Even with these allocations, the financial results are not necessarily indicative of the business segments’ financial condition and results of operations as if they existed as independent entities. The information provided under the caption “Eliminations” represents operations not considered to be reportable segments and/or general operating expenses and eliminations and adjustments, which are necessary for purposes of reconciling to the Consolidated Financial Statements. Three Months Ended September 30, 2016 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 57,804 $ 1 $ 98 $ (95 ) $ 57,808 Interest expense 6,433 — — (80 ) 6,353 Net interest income 51,371 1 98 (15 ) 51,455 Provision for loan losses 2,516 — — — 2,516 Noninterest income 9,548 1,119 2,563 218 13,448 Noninterest expense 28,889 1,097 2,591 203 32,780 Depreciation expense 1,269 11 4 — 1,284 Amortization of intangible assets 359 12 4 — 375 Provision for income taxes 7,347 (1 ) 21 — 7,367 Net Income $ 20,539 $ 1 $ 41 $ — $ 20,581 Three Months Ended September 30, 2015 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 53,625 $ 1 $ 108 $ (65 ) $ 53,669 Interest expense 4,200 — — (127 ) 4,073 Net interest income 49,425 1 108 62 49,596 Provision for loan losses 3,206 — — — 3,206 Noninterest income 8,651 1,197 2,806 (173 ) 12,481 Noninterest expense 28,941 1,098 2,210 (111 ) 32,138 Depreciation expense 1,192 13 6 — 1,211 Amortization of intangible assets 460 13 7 — 480 Provision for income taxes 6,139 26 242 — 6,407 Net Income $ 18,138 $ 48 $ 449 $ — $ 18,635 Nine Months Ended September 30, 2016 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 168,661 $ 2 $ 343 $ (328 ) $ 168,678 Interest expense 18,085 — — (208 ) 17,877 Net interest income 150,576 2 343 (120 ) 150,801 Provision for loan losses 12,379 — — — 12,379 Noninterest income 28,468 3,836 7,936 1,473 41,713 Noninterest expense 90,499 3,455 7,334 1,353 102,641 Depreciation expense 3,678 33 12 — 3,723 Amortization of intangible assets 1,189 37 17 — 1,243 Provision for income taxes 18,364 110 321 — 18,795 Net Income $ 52,935 $ 203 $ 595 $ — $ 53,733 Nine Months Ended September 30, 2015 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 150,108 $ 2 $ 406 $ (321 ) $ 150,195 Interest expense 12,144 — — (615 ) 11,529 Net interest income 137,964 2 406 294 138,666 Provision for loan losses 6,473 — — — 6,473 Noninterest income 25,056 4,079 8,639 174 37,948 Noninterest expense 87,542 3,288 6,716 468 98,014 Depreciation expense 3,482 39 19 — 3,540 Amortization of intangible assets 1,283 38 24 — 1,345 Provision for income taxes 16,534 250 800 — 17,584 Net Income $ 47,706 $ 466 $ 1,486 $ — $ 49,658

Qualified Affordable Housing Pr

Qualified Affordable Housing Projects	9 Months Ended
	Sep. 30, 2016
Investments in Affordable Housing Projects [Abstract]
Qualified Affordable Housing Projects	We invest in affordable housing projects primarily to satisfy our Community Reinvestment Act requirements. As a limited partner in these operating partnerships, we receive tax credits and tax deductions for losses incurred by the underlying properties. We use the cost method to account for these partnerships. Our total investment in qualified affordable housing projects was $12.6 million at September 30, 2016 and $15.0 million at December 31, 2015 . We had no open commitments to fund current or future investments in qualified affordable housing projects at September 30, 2016 or December 31, 2015 . Amortization expense, included in other noninterest expense in the Consolidated Statements of Net Income, was $0.8 million and $2.5 million for the three and nine months ended September 30, 2016 and $0.9 million and $2.8 million for the three and nine months ended September 30, 2015 . The amortization expense was offset by tax credits of $0.9 million and $2.7 million for the three and nine months ended September 30, 2016 and $1.0 million and $3.0 million for the three and nine months ended September 30, 2015 as a reduction to our federal tax provision.

Basis of Presentation (Policies

Basis of Presentation (Policies)	9 Months Ended
	Sep. 30, 2016
Accounting Policies [Abstract]
Principles of Consolidation	Principles of Consolidation The interim Consolidated Financial Statements include the accounts of S&T Bancorp, Inc., or S&T, and its wholly owned subsidiaries. All significant intercompany transactions have been eliminated in consolidation. Investments of 20 percent to 50 percent of the outstanding common stock of investees are accounted for using the equity method of accounting.
Basis of Presentation	Basis of Presentation The accompanying unaudited interim Consolidated Financial Statements of S&T have been prepared in accordance with generally accepted accounting principles, or GAAP, in the United States for interim financial information and with the instructions to Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements and should be read in conjunction with our annual report on Form 10-K for the year ended December 31, 2015 , filed with the Securities and Exchange Commission, or SEC, on February 23, 2016. In the opinion of management, the accompanying interim financial information reflects all adjustments, including normal recurring adjustments, necessary to present fairly our financial position and the results of operations for each of the interim periods presented. Results of operations for interim periods are not necessarily indicative of the results of operations that may be expected for a full year or any future period.
Reclassification	Reclassification A mounts in prior period financial statements and footnotes are reclassified whenever necessary to conform to the current period presentation. Reclassifications had no effect on our results of operations or financial condition.
Use of Estimates	Use of Estimates The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosures of contingent assets and liabilities at the date of the financial statements. Actual results could differ from those estimates.
Recently Adopted Accounting Standards Updates, or ASU, and Recently Issued Accounting Standards Updates not yet Adopted	Recently Adopted Accounting Standards Updates, or ASU Business Combinations - Simplifying the Accounting for Measurement Period Adjustments In September 2015, the Financial Accounting Standards Board, or FASB, issued ASU No. 2015-16, Business Combinations - Simplifying the Accounting for Measurement Period Adjustments (Topic 805). The amendments in this ASU No. 2015-16 eliminate the requirement to retrospectively adjust the financial statements for measurement-period adjustments as if they were known at the acquisition date, but are recognized in the reporting period in which they are determined. Additional disclosures are required about the impact on current-period income statement line items of adjustments that would have been recognized in prior periods if that information had been revised. The measurement period is a reasonable time period after the acquisition date when the acquirer may adjust the provisional amounts recognized for a business combination if the necessary information is not available by the end of the reporting period in which the acquisition occurs. The measurement periods cannot continue for more than one year from the acquisition date. The standard is effective for annual periods and interim periods beginning after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Intangibles - Goodwill and Other - Internal-Use Software: Customer's Accounting for Fees Paid in a Cloud Computing Arrangement In April 2015, the FASB issued ASU No. 2015-05, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer's Accounting for Fees Paid in a Cloud Computing Arrangement. The main provisions of ASU No. 2015-05 provide a basis for evaluating whether a cloud computing arrangement includes a software license. If a cloud computing arrangement includes a software license, then the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses. If a cloud computing arrangement does not include a software license, then the arrangement should be accounted for as a service contract. The standard is effective for annual periods and interim periods beginning after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Interest - Imputation of Interest: Simplifying the Presentation of Debt Issuance Costs In April 2015, the FASB issued ASU No. 2015-03, Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs. The amendments in this ASU require that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. The standard is required to be adopted by public business entities in annual periods beginning on or after December 15, 2015. In September 2015, the FASB issued ASU No. 2015-15, Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements. ASU No. 2015-15 amends the SEC Content in Subtopic 835-30 by adding SEC paragraph 835-30-S35-1, Interest-Imputation of Interest Subsequent Measurement and paragraph 830-30-S45-1, Other Presentation Matters. These paragraphs were added because ASU No. 2015-03 issued in April 2015 does not address presentation or subsequent measurement of debt issuance costs related to "line-of-credit arrangements." The adoption of this ASU had no material impact on our results of operations or financial position. Consolidation: Amendments to the Consolidation Analysis In February 2015, the FASB issued ASU No. 2015-02, Consolidation (Topic 810): Amendments to the Consolidation Analysis. The amendments in this ASU affect reporting entities that are required to evaluate whether they should consolidate certain legal entities. All legal entities are subject to reevaluation under the revised consolidation model. Specifically, the amendments: 1. modify the evaluation of whether limited partnerships and similar legal entities are variable interest entities, or VIEs, or voting interest entities; 2. eliminate the presumption that a general partner should consolidate a limited partnership; 3. affect the consolidation analysis of reporting entities that are involved with VIEs, particularly those that have fee arrangements and related party relationships; and 4. provide a scope exception from consolidation guidance for reporting entities with interests in legal entities that are required to comply with or operate in accordance with requirements that are similar to those in Rule 2A-7 of the Investment Company Act of 1940 for registered money market funds. The amendments in this ASU are effective for public business entities for fiscal years, and for interim periods within those fiscal years, beginning after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Income Statement - Extraordinary and Unusual Items: Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary In January 2015, the FASB issued ASU No. 2015-01, Income Statement - Extraordinary and Unusual Items (Subtopic 225-20): Simplifying Income Statement Presentation by Eliminating the Concept of Extraordinary. The amendments in this ASU No. 2015-01 eliminate from GAAP the concept of extraordinary items and eliminate the requirements for reporting entities to consider whether an underlying event or transaction is extraordinary. The presentation and disclosure guidance for items that are unusual in nature or occur infrequently will be retained and will be expanded to include items that are both unusual in nature and infrequently occurring. The standard is required to be adopted by public business entities in annual periods beginning on or after December 15, 2015. The adoption of this ASU had no impact on our results of operations or financial position. Recently Issued Accounting Standards Updates not yet Adopted Statement of Cash Flows - Classification of Certain Cash Receipts and Cash Payments In August 2016, the FASB issued ASU No. 2016-15, Classification of Certain Cash Receipts and Cash Payments. The main objective of this ASU is to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The amendments in this Update provide guidance on the following eight specific cash flow issues: Debt prepayment or debt extinguishments costs, Settlement of zero-coupon debt instruments, Contingent consideration payments made after a business combination, Proceeds from the settlement of insurance claims, Proceeds from the settlement of bank-owned life insurance (BOLI) policies, Distributions received from equity method investments, Beneficial interests in securitization transactions, and Separately identifiable cash flows and application of the predominance principle. This Update is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. Early adoption is permitted, provided that all of the amendments are adopted in the same period. We are evaluating the provisions of this ASU to determine the potential impact on our results of operations and financial position. Financial Instruments - Credit Losses In June 2016, the FASB issued ASU No. 2016-13, Measurement of Credit Losses on Financial Instruments. The main objective of this ASU is to provide financial statement users with more decision-useful information about the expected credit losses on financial instruments and other commitments to extend credit held by a reporting entity at each reporting date. The amendments of this update replace the incurred loss impairment methodology in current GAAP with a methodology that reflects expected credit losses and requires consideration of a broader range of reasonable and supportable information to inform credit loss estimates. The collective changes to the recognition and measurement accounting standards for financial instruments and their anticipated impact on the allowance for credit losses modeling have been universally referred to as the CECL, or current expected credit loss, model. This Update is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2019. Early adoption is permitted as of fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. We are evaluating the provisions of this ASU to determine the potential impact on our results of operations and financial position. Revenue from Contracts with Customers In May 2014, the FASB issued ASU No. 2014-09, Revenue from Contracts with Customers (Topic 606). The new revenue pronouncement creates a single source of revenue guidance for all companies in all industries and is more principles-based than current revenue guidance. The pronouncement provides a five-step model for a company to recognize revenue when it transfers control of goods or services to customers at an amount that reflects the consideration to which it expects to be entitled in exchange for those goods or services. The five steps are: 1. identify the contract with the customer; 2. identify the separate performance obligations in the contract; 3. determine the transaction price; 4. allocate the transaction price to the separate performance obligations; and 5. recognize revenue when each performance obligation is satisfied. In August 2015, the FASB issued ASU No. 2015-14, Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date. This ASU defers the effective date of ASU No. 2014-09 for all entities by one year. In March 2016, the FASB issued ASU No. 2016-08, Principal versus Agent Considerations (Reporting Revenue Gross versus Net), as an amendment to ASU No. 2014-09 to improve Topic 606, Revenue from Contracts with Customers by reducing: 1. The potential for diversity in practice arising from inconsistent and application of the principal versus agent guidance, and 2. The cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In April 2016, the FASB issued ASU No. 2016-10, Identifying Performance Obligations and Licensing, as an amendment to ASU No. 2014-09 to improve Topic 606, Revenue from Contracts with Customers, by reducing: 1. The potential for diversity in practice at initial application, and 2. The cost and complexity of applying Topic 606 both at transition and on an ongoing basis. In May 2016, the FASB issued ASU No. 2016-12, Narrow-scope Improvements and Practical Expedients. The amendments in this ASU do not change the core principles of Topic 606, Revenue from Contracts with Customers. These amendments affect only the narrow aspects of Topic 606: 1. Collectibility Criterion, 2. Presentation of Sales Taxes and Other Similar Taxes Collected from Customers, 3. Noncash Consideration, 4. Contract Modifications at Transition, and 5. Completed Contracts at Transition. ASU 2014-09, including transition requirements for all amendments, is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. Early adoption is permitted as of the original effective date for interim and annual reporting periods in fiscal years beginning after December 15, 2016. We are evaluating the provisions of these ASUs to determine the potential impact to our results of operations and financial position. Stock Compensation - Improvements to Employee Share-Based Payment Accounting On March 31, 2016, the FASB issued ASU No. 2016-09, Improvements to Employee Share-Based Payment Accounting, which is intended to improve the accounting for share-based payment transactions as part of the FASB's simplification initiative. The ASU changes seven aspects of the accounting for share-based payment award transactions, including; 1. accounting for income taxes; 2. classification of excess tax benefits on the statement of cash flows; 3. forfeitures; 4. minimum statutory tax withholding requirements; 5. classification of employee taxes paid on the statement of cash flows when an employer withholds shares for tax-withholding purposes; 6. practical expedient -- expected term (nonpublic only); and 7. intrinsic value (nonpublic only). This ASU is effective for fiscal years beginning after December 15, 2016 and interim periods within those years for public business entities. Early adoption is permitted in any interim or annual period provided that the entire ASU is adopted. We do not expect that this ASU will have a material impact on our results of operations and financial position. Equity Method and Joint Ventures - Simplifying the Transition to the Equity Method of Accounting In March 2016, the FASB issued ASU No. 2016-07, Simplifying the Transition to the Equity Method of Accounting, which eliminates the requirement for an investor to retroactively apply the equity method when its increase in ownership interest (or degree of influence) in an investee triggers equity method accounting. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2016. The amendments should be applied prospectively upon their effective date to increases in the level of ownership interest or degree of influence that result in the adoption of the equity method. Earlier application is permitted. We do not expect that this ASU will have a material impact on our results of operations and financial position. Leases - Section A-Amendments to the FASB Accounting Standards Codification, Section B-Conforming Amendments Related to Leases and Section C-Background Information and Basis for Conclusions In February 2016, the FASB issued ASU No. 2016-02, Leases, which requires lessees to recognize a right-to-use asset and a lease obligation for all leases on the balance sheet. Lessor accounting remains substantially similar to current GAAP. ASU 2016-02 supersedes Topic 840, Leases. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2018. ASU 2016-02 mandates a modified retrospective transition method for all entities. Early adoption of this ASU is permitted. We anticipate that this ASU will impact our financial statements as it relates to the recognition of right-to-use assets and lease obligations on our Consolidated Balance Sheet. However, we do not expect that this ASU will have a material impact on our Consolidated Statement of Comprehensive Income. Accounting for Financial Instruments - Overall: Classification and Measurement In January 2016, the FASB issued ASU No. 2016-01, Accounting for Financial Instruments - Overall: Classification and Measurement (Subtopic 825-10). The amendments in this ASU No. 2016-01 address the following: 1. require equity investments to be measured at fair value with changes in fair value recognized in net income; 2. simplify the impairment assessment of equity investments without readily-determinable fair values by requiring a qualitative assessment to identify impairment; 3. eliminate the requirement to disclose the method(s) and significant assumptions used to estimate the fair value that is required to be disclosed for financial instruments measured at amortized cost on the balance sheet; 4. require entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes; 5. require separate presentation in other comprehensive income for the portion of the total change in the fair value of a liability resulting from a change in the instrument-specific credit risk when the entity has elected to measure the liability at fair value in accordance with the fair value option for financial instruments; 6. require separate presentation of financial assets and financial liabilities by measurement category and form of financial asset (that is, securities or loans and receivables) on the balance sheet or the accompanying notes to the financial statements; and 7. clarify that an entity should evaluate the need for a valuation allowance on a deferred tax asset related to available-for-sale securities in combination with the entity's other deferred tax assets. This ASU is effective for annual and interim periods in fiscal years beginning after December 15, 2017. We anticipate that this ASU will have a significant impact on our financial statements and disclosures primarily as it relates to recognizing the fair value changes for equity securities in net income rather than an adjustment to equity through other comprehensive income.
Fair Value Measurements	We use fair value measurements when recording and disclosing certain financial assets and liabilities. Securities available-for-sale, trading assets and derivative financial instruments are recorded at fair value on a recurring basis. Additionally, from time to time, we may be required to record other assets at fair value on a nonrecurring basis, such as loans held for sale, impaired loans, other real estate owned, or OREO, and other repossessed assets, mortgage servicing rights, or MSRs, and certain other assets. Fair value is the price that would be received to sell an asset or paid to transfer a liability in the principal or most advantageous market in an orderly transaction between market participants at the measurement date. An orderly transaction is a transaction that assumes exposure to the market for a period prior to the measurement date to allow for marketing activities that are usual and customary for transactions involving such assets or liabilities; it is not a forced transaction. In determining fair value, we use various valuation approaches, including market, income and cost approaches. The fair value standard establishes a hierarchy for inputs used in measuring fair value that maximizes the use of observable inputs and minimizes the use of unobservable inputs by requiring that observable inputs be used when available. Observable inputs are inputs that market participants would use in pricing an asset or liability, which is developed, based on market data we have obtained from independent sources. Unobservable inputs reflect our estimates of assumptions that market participants would use in pricing an asset or liability, which are developed based on the best information available in the circumstances. The fair value hierarchy gives the highest priority to unadjusted quoted market prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to unobservable inputs (Level 3 measurement). The fair value hierarchy is broken down into three levels based on the reliability of inputs as follows: Level 1: valuation is based upon unadjusted quoted market prices for identical instruments traded in active markets. Level 2: valuation is based upon quoted market prices for similar instruments traded in active markets, quoted market prices for identical or similar instruments traded in markets that are not active and model-based valuation techniques for which all significant assumptions are observable in the market or can be corroborated by market data. Level 3: valuation is derived from other valuation methodologies, including discounted cash flow models and similar techniques that use significant assumptions not observable in the market. These unobservable assumptions reflect estimates of assumptions that market participants would use in determining fair value. A financial instrument’s level within the fair value hierarchy is based on the lowest level of input that is significant to the fair value measurement. Our policy is to recognize transfers between any of the fair value hierarchy levels at the end of the reporting period in which the transfer occurred. The following are descriptions of the valuation methodologies that we use for financial instruments recorded at fair value on either a recurring or nonrecurring basis. Recurring Basis Securities Available-for-Sale Securities available-for-sale include both debt and equity securities. We obtain fair values for debt securities from a third-party pricing service which utilizes several sources for valuing fixed-income securities. We validate prices received from our pricing service through comparison to a secondary pricing service and broker quotes. We review the methodologies of the pricing service which provides us with a sufficient understanding of the valuation models, assumptions, inputs and pricing to reasonably measure the fair value of our debt securities. The market evaluation sources for debt securities include observable inputs rather than significant unobservable inputs and are classified as Level 2. The service provider utilizes pricing models that vary by asset class and include available trade, bid and other market information. Generally, the methodologies include broker quotes, proprietary models and vast descriptive terms and conditions databases, as well as extensive quality control programs. Marketable equity securities that have an active, quotable market are classified as Level 1. Marketable equity securities that are quotable, but are thinly traded or inactive, are classified as Level 2. Marketable equity securities that are not readily traded and do not have a quotable market are classified as Level 3. Trading Assets We use quoted market prices to determine the fair value of our trading assets. Our trading assets are held in a Rabbi Trust under a deferred compensation plan and are invested in readily quoted mutual funds. Accordingly, these assets are classified as Level 1. Derivative Financial Instruments We use derivative instruments, including interest rate swaps for commercial loans with our customers, interest rate lock commitments and the sale of mortgage loans in the secondary market. We calculate the fair value for derivatives using widely accepted valuation techniques, including discounted cash flow analysis on the expected cash flows of each derivative. Each valuation considers the contractual terms of the derivative, including the period to maturity, and uses observable market based inputs, such as interest rate curves and implied volatilities. Accordingly, derivatives are classified as Level 2. We incorporate credit valuation adjustments into the valuation models to appropriately reflect both our own nonperformance risk and the respective counterparties' nonperformance risk in calculating fair value measurements. In adjusting the fair value of our derivative contracts for the effect of nonperformance risk, we have considered the impact of netting and any applicable credit enhancements and collateral postings. Nonrecurring Basis Loans Held for Sale Loans held for sale consist of 1-4 family residential loans originated for sale in the secondary market and, from time to time, certain loans transferred from the loan portfolio to loans held for sale, all of which are carried at the lower of cost or fair value. The fair value of 1-4 family residential loans is based on the principal or most advantageous market currently offered for similar loans using observable market data. The fair value of the loans transferred from the loan portfolio is based on the amounts offered for these loans in currently pending sales transactions. Loans held for sale carried at fair value are classified as Level 3. Impaired Loans Impaired loans are carried at the lower of carrying value or fair value. Fair value is determined as the recorded investment balance less any specific reserve. We establish specific reserves based on the following three impairment methods: 1) the present value of expected future cash flows discounted at the loan’s original effective interest rate; 2) the loan’s observable market price; or 3) the fair value of the collateral less estimated selling costs when the loan is collateral dependent and we expect to liquidate the collateral. However, if repayment is expected to come from the operation of the collateral, rather than liquidation, then we do not consider estimated selling costs in determining the fair value of the collateral. Collateral values are generally based upon appraisals by approved, independent state certified appraisers. Appraisals may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or our knowledge of the borrower and the borrower’s business. Impaired loans carried at fair value are classified as Level 3. OREO and Other Repossessed Assets OREO and other repossessed assets obtained in partial or total satisfaction of a loan are recorded at the lower of recorded investment in the loan or fair value less cost to sell. Subsequent to foreclosure, these assets are carried at the lower of the amount recorded at acquisition date or fair value less cost to sell. Accordingly, it may be necessary to record nonrecurring fair value adjustments. Fair value, when recorded, is generally based upon appraisals by approved, independent state certified appraisers. Like impaired loans, appraisals on OREO may be discounted based on our historical knowledge, changes in market conditions from the time of appraisal or other information available to us. OREO and other repossessed assets carried at fair value are classified as Level 3. Mortgage Servicing Rights The fair value of MSRs is determined by calculating the present value of estimated future net servicing cash flows, considering expected mortgage loan prepayment rates, discount rates, servicing costs and other economic factors, which are determined based on current market conditions. The expected rate of mortgage loan prepayments is the most significant factor driving the value of MSRs. MSRs are considered impaired if the carrying value exceeds fair value. The valuation model includes significant unobservable inputs; therefore, MSRs are classified as Level 3. Other Assets We measure certain other assets at fair value on a nonrecurring basis. Fair value is based on the application of lower of cost or fair value accounting, or write-downs of individual assets. Valuation methodologies used to measure fair value are consistent with overall principles of fair value accounting and consistent with those described above. Financial Instruments In addition to financial instruments recorded at fair value in our financial statements, fair value accounting guidance requires disclosure of the fair value of all of an entity’s assets and liabilities that are considered financial instruments. The majority of our assets and liabilities are considered financial instruments. Many of these instruments lack an available trading market as characterized by a willing buyer and willing seller engaged in an exchange transaction. Also, it is our general practice and intent to hold our financial instruments to maturity and to not engage in trading or sales activities with respect to such financial instruments. For fair value disclosure purposes, we substantially utilize the fair value measurement criteria as required and explained above. In cases where quoted fair values are not available, we use present value methods to determine the fair value of our financial instruments. Cash and Cash Equivalents The carrying amounts reported in the Consolidated Balance Sheets for cash and due from banks, including interest-bearing deposits, approximate fair value. Loans The fair value of variable rate performing loans that may reprice frequently at short-term market rates is based on carrying values adjusted for credit risk. The fair value of variable rate performing loans that reprice at intervals of one year or longer, such as adjustable rate mortgage products, is estimated using discounted cash flow analyses that utilize interest rates currently being offered for similar loans and adjusted for credit risk. The fair value of fixed rate performing loans is estimated using a discounted cash flow analysis that utilizes interest rates currently being offered for similar loans and adjusted for credit risk. The fair value of nonperforming loans is the carrying value less any specific reserve on the loan if it is impaired. The carrying amount of accrued interest approximates fair value. Bank Owned Life Insurance Fair value approximates net cash surrender value of bank owned life insurance. Federal Home Loan Bank, or FHLB, and Other Restricted Stock It is not practical to determine the fair value of our FHLB and other restricted stock due to the restrictions placed on the transferability of these stocks; it is presented at carrying value. Deposits The fair values disclosed for deposits without defined maturities (e.g., noninterest and interest-bearing demand, money market and savings accounts) are by definition equal to the amounts payable on demand. The carrying amounts for variable rate, fixed-term time deposits approximate their fair values. Estimated fair values for fixed rate and other time deposits are based on discounted cash flow analysis using interest rates currently offered for time deposits with similar terms. The carrying amount of accrued interest approximates fair value. Short-Term Borrowings The carrying amounts of securities sold under repurchase agreements, or REPOs, and other short-term borrowings approximate their fair values. Long-Term Borrowings The fair values disclosed for fixed rate long-term borrowings are determined by discounting their contractual cash flows using current interest rates for long-term borrowings of similar remaining maturities. The carrying amounts of variable rate long-term borrowings approximate their fair values. Junior Subordinated Debt Securities The interest rate on the variable rate junior subordinated debt securities is reset quarterly; therefore, the carrying values approximate their fair values. Loan Commitments and Standby Letters of Credit Off-balance sheet financial instruments consist of commitments to extend credit and letters of credit. Except for interest rate lock commitments, estimates of the fair value of these off-balance sheet items are not made because of the short-term nature of these arrangements and the credit standing of the counterparties. Other Estimates of fair value are not made for items that are not defined as financial instruments, including such items as our core deposit intangibles and the value of our trust operations.
Allowance for Loans Losses by Portfolio	We maintain an allowance for loan losses, or ALL, at a level determined to be adequate to absorb estimated probable credit losses inherent in the loan portfolio as of the balance sheet date. We develop and document a systematic ALL methodology based on the following portfolio segments: 1) CRE, 2) C&I, 3) Commercial Construction, 4) Consumer Real Estate and 5) Other Consumer. The following are key risks within each portfolio segment: CRE —Loans secured by commercial purpose real estate, including both owner occupied properties and investment properties, for various purposes such as hotels, strip malls and apartments. Operations of the individual projects as well as global cash flows of the debtors are the primary sources of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the collateral type as well as the business prospects of the lessee, if the project is not owner occupied. C&I —Loans made to operating companies or manufacturers for the purpose of production, operating capacity, accounts receivable, inventory or equipment financing. Cash flow from the operations of the company is the primary source of repayment for these loans. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the industry of the company. Collateral for these types of loans often does not have sufficient value in a distressed or liquidation scenario to satisfy the outstanding debt. Commercial Construction —Loans made to finance construction of buildings or other structures, as well as to finance the acquisition and development of raw land for various purposes. While the risk of these loans is generally confined to the construction period, if there are problems, the project may not be completed, and as such, may not provide sufficient cash flow on its own to service the debt or have sufficient value in a liquidation to cover the outstanding principal. The condition of the local economy is an important indicator of risk, but there are also more specific risks depending on the type of project and the experience and resources of the developer. Consumer Real Estate —Loans secured by first and second liens such as home equity loans, home equity lines of credit and 1-4 family residential mortgages, including purchase money mortgages. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The state of the local housing market can also have a significant impact on this segment because low demand and/or declining home values can limit the ability of borrowers to sell a property and satisfy the debt. Other Consumer —Loans made to individuals that may be secured by assets other than 1-4 family residences, as well as unsecured loans. This segment includes auto loans, unsecured loans and lines and credit cards. The primary source of repayment for these loans is the income and assets of the borrower. The condition of the local economy, in particular the unemployment rate, is an important indicator of risk for this segment. The value of the collateral, if there is any, is less likely to be a source of repayment due to less certain collateral values. We further assess risk within each portfolio segment by pooling loans with similar risk characteristics. For the commercial loan classes, the most important indicator of risk is the internally assigned risk rating, including pass, special mention and substandard. Consumer loans are pooled by type of collateral, lien position and loan to value, or LTV, ratio for Consumer Real Estate loans. Historical loss rates are applied to these loan pools to determine the reserve for loans collectively evaluated for impairment. The ALL methodology for groups of loans collectively evaluated for impairment is comprised of both a quantitative and qualitative analysis. A key assumption in the quantitative component of the reserve is the loss emergence period, or LEP. The LEP is an estimate of the average amount of time from the point at which a loss is incurred on a loan to the point at which the loss is confirmed. Another key assumption is the look-back period, or LBP, which represents the historical data period utilized to calculate loss rates. Management monitors various credit quality indicators for both the commercial and consumer loan portfolios, including delinquency, nonperforming status and changes in risk ratings on a monthly basis.
Loans Credit Risk Rating	We continually monitor the commercial loan portfolio through an internal risk rating system. Loan risk ratings are assigned based upon the creditworthiness of the borrower and are reviewed on an ongoing basis according to our internal policies. Loans within the pass rating generally have a lower risk of loss than loans risk rated as special mention or substandard. Our risk ratings are consistent with regulatory guidance and are as follows: Pass —The loan is currently performing and is of high quality. Special Mention —A special mention loan has potential weaknesses that warrant management’s close attention. If left uncorrected, these potential weaknesses may result in deterioration of the repayment prospects or in the strength of our credit position at some future date. Economic and market conditions, beyond the borrower’s control, may in the future necessitate this classification. Substandard —A substandard loan is not adequately protected by the net worth and/or paying capacity of the borrower or by the collateral pledged, if any. Substandard loans have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. These loans are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected.
Derivative Financial Instruments	Interest Rate Swaps In accordance with applicable accounting guidance for derivatives and hedging, all derivatives are recognized as either assets or liabilities on the balance sheet at fair value. Interest rate swaps are contracts in which a series of interest rate flows (fixed and variable) are exchanged over a prescribed period. The notional amounts on which the interest payments are based are not exchanged. These derivative positions relate to transactions in which we enter into an interest rate swap with a commercial customer while at the same time entering into an offsetting interest rate swap with another financial institution. In connection with each transaction, we agree to pay interest to the customer on a notional amount at a variable interest rate and receive interest from the customer on the same notional amount at a fixed rate. At the same time, we agree to pay another financial institution the same fixed interest rate on the same notional amount and receive the same variable interest rate on the same notional amount. The transaction allows our customer to effectively convert a variable rate loan to a fixed rate loan with us receiving a variable rate. These agreements could have floors or caps on the contracted interest rates. Pursuant to our agreements with various financial institutions, we may receive collateral or may be required to post collateral based upon mark-to-market positions. Beyond unsecured threshold levels, collateral in the form of cash or securities may be made available to counterparties of interest rate swap transactions. Based upon our current positions and related future collateral requirements relating to them, we believe any effect on our cash flow or liquidity position to be immaterial. Derivatives contain an element of credit risk, the possibility that we will incur a loss because a counterparty, which may be a financial institution or a customer, fails to meet its contractual obligations. All derivative contracts with financial institutions may be executed only with counterparties approved by our Asset and Liability Committee, or ALCO, and derivatives with customers may only be executed with customers within credit exposure limits approved by our Senior Loan Committee. Interest rate swaps are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the estimated fair value of the derivatives are recorded in current earnings and included in other noninterest income in the Consolidated Statements of Net Income. Interest Rate Lock Commitments and Forward Sale Contracts In the normal course of business, we sell originated mortgage loans into the secondary mortgage loan market. We also offer interest rate lock commitments to potential borrowers. The commitments are generally for a period of 60 days and guarantee a specified interest rate for a loan if underwriting standards are met, but the commitment does not obligate the potential borrower to close on the loan. Accordingly, some commitments expire prior to becoming loans. We may encounter pricing risks if interest rates increase significantly before the loan can be closed and sold. We may utilize forward sale contracts in order to mitigate this pricing risk. Whenever a customer desires these products, a mortgage originator quotes a secondary market rate guaranteed for that day by the investor. The rate lock is executed between the mortgagee and us and in turn a forward sale contract may be executed between us and the investor. Both the rate lock commitment and the corresponding forward sale contract for each customer are considered derivatives, but are not accounted for using hedge accounting. As such, changes in the estimated fair value of the derivatives during the commitment period are recorded in current earnings and included in mortgage banking in the Consolidated Statements of Net Income.

Business Combinations (Tables)

Business Combinations (Tables)	9 Months Ended
	Sep. 30, 2016
Business Combinations [Abstract]
Summary of Consideration, Assets Acquired and Liabilities Assumed	The following table summarizes total consideration, assets acquired and liabilities assumed from the Merger: (dollars in thousands) Consideration Paid Cash $ 29,510 Common stock 142,469 Fair Value of Total Consideration $ 171,979 Fair Value of Assets Acquired Cash and cash equivalents $ 13,163 Securities and other investments 11,502 Loans 788,687 Bank owned life insurance 15,974 Premises and equipment 10,855 Core deposit intangible 5,713 Other assets 19,088 Total Assets Acquired 864,982 Fair Value of Liabilities Assumed Deposits 722,308 Borrowings 82,286 Other liabilities 4,259 Total Liabilities Assumed 808,853 Total Fair Value of Identifiable Net Assets 56,129 Goodwill $ 115,850

Earnings Per Share (Tables)

Earnings Per Share (Tables)	9 Months Ended
	Sep. 30, 2016
Earnings Per Share [Abstract]
Reconciles Numerators and Denominators of Basic Earnings Per Share with Diluted Earnings Per Share	The following table reconciles the numerators and denominators of basic and diluted earnings per share for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, (in thousands, except shares and per share data) 2016 2015 2016 2015 Numerator for Earnings per Share—Basic: Net income $ 20,581 $ 18,635 $ 53,733 $ 49,658 Less: Income allocated to participating shares 68 81 167 204 Net Income Allocated to Shareholders $ 20,513 $ 18,554 $ 53,566 $ 49,454 Numerator for Earnings per Share—Diluted: Net income $ 20,581 $ 18,635 $ 53,733 $ 49,658 Net Income Available to Shareholders $ 20,581 $ 18,635 $ 53,733 $ 49,658 Denominators for Earnings per Share: Weighted Average Shares Outstanding—Basic 34,687,487 34,660,007 34,674,453 33,527,549 Add: Potentially dilutive shares 81,018 32,985 72,724 33,980 Denominator for Treasury Stock Method—Diluted 34,768,505 34,692,992 34,747,177 33,561,529 Weighted Average Shares Outstanding—Basic 34,687,487 34,660,007 34,674,453 33,527,549 Add: Average participating shares outstanding 114,746 151,972 108,414 138,441 Denominator for Two-Class Method—Diluted 34,802,233 34,811,979 34,782,867 33,665,990 Earnings per share—basic $ 0.59 $ 0.54 $ 1.55 $ 1.48 Earnings per share—diluted $ 0.59 $ 0.54 $ 1.54 $ 1.48 Warrants considered anti-dilutive excluded from potentially dilutive shares - exercise price $31.53 per share, expire January 2019 517,012 517,012 517,012 517,012 Stock options considered anti-dilutive excluded from potentially dilutive shares - expired in December 2015 — 155,500 — 155,500 Restricted stock considered anti-dilutive excluded from potentially dilutive shares 146,695 118,987 134,983 104,461

Fair Value Measurement (Tables)

Fair Value Measurement (Tables)	9 Months Ended
	Sep. 30, 2016
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on Recurring Basis	The following tables present our assets and liabilities that are measured at fair value on a recurring basis by fair value hierarchy level at September 30, 2016 and December 31, 2015 . There were no transfers between Level 1 and Level 2 for items measured at fair value on a recurring basis during the periods presented. September 30, 2016 (dollars in thousands) Level 1 Level 2 Level 3 Total ASSETS Securities available-for-sale: U.S. Treasury securities $ — $ 15,056 $ — $ 15,056 Obligations of U.S. government corporations and agencies — 250,924 — 250,924 Collateralized mortgage obligations of U.S. government corporations and agencies — 137,460 — 137,460 Residential mortgage-backed securities of U.S. government corporations and agencies — 36,285 — 36,285 Commercial mortgage-backed securities of U.S. government corporations and agencies — 88,499 — 88,499 Obligations of states and political subdivisions — 132,536 — 132,536 Marketable equity securities — 10,368 — 10,368 Total securities available-for-sale — 671,128 — 671,128 Trading securities held in a Rabbi Trust 4,312 — — 4,312 Total securities 4,312 671,128 — 675,440 Derivative financial assets: Interest rate swap contracts - commercial loans — 15,255 — 15,255 Interest rate lock commitments - mortgage loans — 739 — 739 Total Assets $ 4,312 $ 687,122 $ — $ 691,434 LIABILITIES Derivative financial liabilities: Interest rate swap contracts - commercial loans $ — $ 15,202 $ — $ 15,202 Forward sale contracts - mortgage loans — 98 — 98 Total Liabilities $ — $ 15,300 $ — $ 15,300 December 31, 2015 (dollars in thousands) Level 1 Level 2 Level 3 Total ASSETS Securities available-for-sale: U.S. Treasury securities $ — $ 14,941 $ — $ 14,941 Obligations of U.S. government corporations and agencies — 263,303 — 263,303 Collateralized mortgage obligations of U.S. government corporations and agencies — 128,835 — 128,835 Residential mortgage-backed securities of U.S. government corporations and agencies — 40,125 — 40,125 Commercial mortgage-backed securities of U.S. government corporations and agencies — 69,204 — 69,204 Obligations of states and political subdivisions — 134,886 — 134,886 Marketable equity securities — 9,669 — 9,669 Total securities available-for-sale — 660,963 — 660,963 Trading securities held in a Rabbi Trust 4,021 — — 4,021 Total securities 4,021 660,963 — 664,984 Derivative financial assets: Interest rate swap contracts - commercial loans — 11,295 — 11,295 Interest rate lock commitments - mortgage loans — 261 — 261 Total Assets $ 4,021 $ 672,519 $ — $ 676,540 LIABILITIES Derivative financial liabilities: Interest rate swap contracts - commercial loans $ — $ 11,276 $ — $ 11,276 Forward sale contracts - mortgage loans — 5 — 5 Total Liabilities $ — $ 11,281 $ — $ 11,281
Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy	The following table presents our assets that are measured at fair value on a nonrecurring basis by the fair value hierarchy level as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Level 1 Level 2 Level 3 Total Level 1 Level 2 Level 3 Total ASSETS (1) Impaired loans — — 9,000 9,000 — — 9,373 9,373 Other real estate owned — — 181 181 — — 158 158 Mortgage servicing rights — — 3,253 3,253 — — 3,396 3,396 Total Assets $ — $ — $ 12,434 $ 12,434 $ — $ — $ 12,927 $ 12,927 (1) This table presents only the nonrecurring items that are recorded at fair value in our financial statements.
Carrying Values and Fair Values of Financial Instruments	The carrying values and fair values of our financial instruments at September 30, 2016 and December 31, 2015 are presented in the following tables: Carrying Value (1) Fair Value Measurements at September 30, 2016 (dollars in thousands) Total Level 1 Level 2 Level 3 ASSETS Cash and due from banks, including interest-bearing deposits $ 125,163 $ 125,163 $ 125,163 $ — $ — Securities available-for-sale 671,128 671,128 — 671,128 — Loans held for sale 11,695 12,176 — — 12,176 Portfolio loans, net of unearned income 5,418,234 5,406,298 — — 5,406,298 Bank owned life insurance 71,523 71,523 — 71,523 — FHLB and other restricted stock 28,331 28,331 — — 28,331 Trading securities held in a Rabbi Trust 4,312 4,312 4,312 — — Mortgage servicing rights 3,252 3,253 — — 3,253 Interest rate swap contracts - commercial loans 15,255 15,255 — 15,255 — Interest rate lock commitments - mortgage loans 739 739 — 739 — LIABILITIES Deposits $ 5,145,431 $ 5,151,031 $ — $ — $ 5,151,031 Securities sold under repurchase agreements 40,949 40,949 — — 40,949 Short-term borrowings 565,000 565,000 — — 565,000 Long-term borrowings 15,303 16,111 — — 16,111 Junior subordinated debt securities 45,619 45,619 — — 45,619 Interest rate swap contracts - commercial loans 15,202 15,202 — 15,202 — Forward sale contracts - mortgage loans 98 98 — 98 — (1) As reported in the Consolidated Balance Sheets Carrying Value (1) Fair Value Measurements at December 31, 2015 (dollars in thousands) Total Level 1 Level 2 Level 3 ASSETS Cash and due from banks, including interest-bearing deposits $ 99,399 $ 99,399 $ 99,399 $ — $ — Securities available-for-sale 660,963 660,963 — 660,963 — Loans held for sale 35,321 35,500 — — 35,500 Portfolio loans, net of unearned income 5,027,612 5,001,004 — — 5,001,004 Bank owned life insurance 70,175 70,175 — 70,175 — FHLB and other restricted stock 23,032 23,032 — — 23,032 Trading securities held in a Rabbi Trust 4,021 4,021 4,021 — — Mortgage servicing rights 3,237 3,396 — — 3,396 Interest rate swap contracts - commercial loans 11,295 11,295 — 11,295 — Interest rate lock commitments - mortgage loans 261 261 — 261 — LIABILITIES Deposits $ 4,876,611 $ 4,881,718 $ — $ — $ 4,881,718 Securities sold under repurchase agreements 62,086 62,086 — — 62,086 Short-term borrowings 356,000 356,000 — — 356,000 Long-term borrowings 117,043 117,859 — — 117,859 Junior subordinated debt securities 45,619 45,619 — — 45,619 Interest rate swap contracts - commercial loans 11,276 11,276 — 11,276 — Forward sale contracts - mortgage loans 5 5 — 5 — (1) As reported in the Consolidated Balance Sheets

Securities Available-for-Sale (

Securities Available-for-Sale (Tables)	9 Months Ended
	Sep. 30, 2016
Investments, Debt and Equity Securities [Abstract]
Composition of Securities Available-for-Sale	The following tables present the amortized cost and fair value of available-for-sale securities as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value Amortized Cost Gross Unrealized Gains Gross Unrealized Losses Fair Value U.S. treasury securities $ 14,944 $ 112 $ — $ 15,056 $ 14,914 $ 27 $ — $ 14,941 Obligations of U.S. government corporations and agencies 246,259 4,665 — 250,924 262,045 1,825 (567 ) 263,303 Collateralized mortgage obligations of U.S. government corporations and agencies 134,675 2,785 — 137,460 128,458 693 (316 ) 128,835 Residential mortgage-backed securities of U.S. government corporations and agencies 34,685 1,600 — 36,285 39,185 1,091 (151 ) 40,125 Commercial mortgage-backed securities of U.S. government corporations and agencies 86,827 1,680 (8 ) 88,499 69,697 183 (676 ) 69,204 Obligations of states and political subdivisions 124,229 8,307 — 132,536 128,904 5,988 (6 ) 134,886 Debt Securities 641,619 19,149 (8 ) 660,760 643,203 9,807 (1,716 ) 651,294 Marketable equity securities 7,579 2,789 — 10,368 7,579 2,090 — 9,669 Total $ 649,198 $ 21,938 $ (8 ) $ 671,128 $ 650,782 $ 11,897 $ (1,716 ) $ 660,963
Fair Value and Age of Gross Unrealized Losses by Investment Category	The following tables present the fair value and the age of gross unrealized losses by investment category as of the dates presented: September 30, 2016 Less Than 12 Months 12 Months or More Total (dollars in thousands) Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized U.S. Treasury securities — $ — $ — — $ — $ — — $ — $ — Obligations of U.S. government corporations and agencies — — — — — — — — — Collateralized mortgage obligations of U.S. government corporations and agencies — — — — — — — — — Residential mortgage-backed securities of U.S. government corporations and agencies — — — — — — — — — Commercial mortgage-backed securities of U.S. government corporations and agencies 1 7,841 (8 ) — — — 1 7,841 (8 ) Obligations of states and political subdivisions — — — — — — — — — Debt Securities 1 7,841 (8 ) — — — 1 7,841 (8 ) Marketable equity securities 1 71 — — — — 1 71 — Total Temporarily Impaired Securities 2 $ 7,912 $ (8 ) — $ — $ — 2 $ 7,912 $ (8 ) December 31, 2015 Less Than 12 Months 12 Months or More Total (dollars in thousands) Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized Number of Securities Fair Value Unrealized U.S. Treasury securities — $ — $ — — $ — $ — — $ — $ — Obligations of U.S. government corporations and agencies 10 88,584 (379 ) 2 14,542 (188 ) 12 103,126 (567 ) Collateralized mortgage obligations of U.S. government corporations and agencies 6 61,211 (316 ) — — — 6 61,211 (316 ) Residential mortgage-backed securities of U.S. government corporations and agencies 1 7,993 (151 ) — — — 1 7,993 (151 ) Commercial mortgage-backed securities of U.S. government corporations and agencies 5 50,839 (450 ) 1 9,472 (226 ) 6 60,311 (676 ) Obligations of states and political subdivisions 1 5,370 (6 ) — — — 1 5,370 (6 ) Debt Securities 23 213,997 (1,302 ) 3 24,014 (414 ) 26 238,011 (1,716 ) Marketable equity securities — — — — — — — — — Total Temporarily Impaired Securities 23 $ 213,997 $ (1,302 ) 3 $ 24,014 $ (414 ) 26 $ 238,011 $ (1,716 )
Unrealized Gains and Losses, Net of Tax on Securities Available for Sale	The following table displays net unrealized gains and losses, net of tax on securities available for sale included in accumulated other comprehensive (loss)/income, for the periods presented: September 30, 2016 December 31, 2015 (dollars in thousands) Gross Unrealized Gains Gross Unrealized Losses Net Unrealized Gains/ (Losses) Gross Unrealized Gains Gross Unrealized Losses Net Unrealized Gains/ (Losses) Total unrealized gains/(losses) on securities available-for-sale $ 21,938 $ (8 ) $ 21,930 $ 11,897 $ (1,716 ) $ 10,181 Income tax expense/(benefit) 7,678 (3 ) 7,675 4,164 (601 ) 3,563 Net unrealized gains/(losses), net of tax included in accumulated other comprehensive income/(loss) $ 14,260 $ (5 ) $ 14,255 $ 7,733 $ (1,115 ) $ 6,618
Amortized Cost and Fair Value of Available-for-Sale Securities	The amortized cost and fair value of securities available-for-sale at September 30, 2016 by contractual maturity are included in the table below. Actual maturities may differ from contractual maturities because issuers may have the right to call or prepay obligations with or without call or prepayment penalties. September 30, 2016 (dollars in thousands) Amortized Cost Fair Value Obligations of the U.S. Treasury, U.S. government corporations and agencies, and obligations of states and political subdivisions Due in one year or less $ 52,302 $ 52,439 Due after one year through five years 216,729 222,114 Due after five years through ten years 55,893 58,699 Due after ten years 60,508 65,264 385,432 398,516 Collateralized mortgage obligations of U.S. government corporations and agencies 134,675 137,460 Residential mortgage-backed securities of U.S. government corporations and agencies 34,685 36,285 Commercial mortgage-backed securities of U.S. government corporations and agencies 86,827 88,499 Debt Securities 641,619 660,760 Marketable equity securities 7,579 10,368 Total $ 649,198 $ 671,128

Loans and Loans Held for Sale (

Loans and Loans Held for Sale (Tables)	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Composition of Loans	The following table indicates the composition of loans as of the dates presented: (dollars in thousands) September 30, 2016 December 31, 2015 Commercial Commercial real estate $ 2,427,164 $ 2,166,603 Commercial and industrial 1,344,297 1,256,830 Commercial construction 402,124 413,444 Total Commercial Loans 4,173,585 3,836,877 Consumer Residential mortgage 692,574 639,372 Home equity 483,935 470,845 Installment and other consumer 62,288 73,939 Consumer construction 5,852 6,579 Total Consumer Loans 1,244,649 1,190,735 Total Portfolio Loans 5,418,234 5,027,612 Loans held for sale 11,694 35,321 Total Loans $ 5,429,928 $ 5,062,933
Restructured Loans for Periods Presented	The following table summarizes the restructured loans as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Performing TDRs Nonperforming TDRs Total TDRs Performing TDRs Nonperforming TDRs Total TDRs Commercial real estate $ 3,054 $ 866 $ 3,920 $ 6,822 $ 3,548 $ 10,370 Commercial and industrial 863 7,007 7,870 6,321 1,570 7,891 Commercial construction 3,460 992 4,452 5,013 1,265 6,278 Residential mortgage 2,453 5,248 7,701 2,590 665 3,255 Home equity 3,084 973 4,057 3,184 523 3,707 Installment and other consumer 22 9 31 25 88 113 Total $ 12,936 $ 15,095 $ 28,031 $ 23,955 $ 7,659 $ 31,614 he following tables present the restructured loans during the periods presented: Three Months Ended September 30, 2016 Three Months Ended September 30, 2015 (dollars in thousands) Number of Loans Pre-Modification Outstanding Recorded Investment ( 1) Post-Modification Outstanding Recorded Investment (1) Total Difference in Recorded Investment Number of Loans Pre-Modification Outstanding Recorded Investment (1) Post-Modification Outstanding Recorded Investment (1) Total Difference in Recorded Investment Commercial real estate Interest rate reduction 1 $ 250 $ 248 $ (2 ) — $ — $ — $ — Maturity date extension — — — — 1 264 260 (4 ) Commercial and industrial Maturity date extension 2 4,105 4,162 57 — — — — Commercial Construction Maturity date extension — — — — 2 813 812 (1 ) Residential mortgage Chapter 7 bankruptcy (2) 3 153 152 (1 ) 2 74 74 — Maturity date extension — — — — 1 180 180 — Maturity date extension and interest rate reduction 1 280 280 — — — — — Home equity Chapter 7 bankruptcy (2) 7 163 161 (2 ) 5 115 110 (5 ) Maturity date extension and interest rate reduction — — — — 2 138 138 — Installment and other consumer Chapter 7 bankruptcy (2) — — — — 1 9 4 (5 ) Total by Concession Type Chapter 7 bankruptcy (2) 10 $ 316 $ 313 $ (3 ) 8 $ 198 $ 188 $ (10 ) Interest rate reduction 1 250 248 (2 ) — — — — Maturity date extension and interest rate reduction 1 280 280 — 2 138 138 — Maturity date extension 2 4,105 4,162 57 4 1,257 1,252 (5 ) Total 14 $ 4,951 $ 5,003 $ 52 14 $ 1,593 $ 1,578 $ (15 ) (1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end. (2) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed. Nine Months Ended September 30, 2016 Nine Months Ended September 30, 2015 (dollars in thousands) Number of Pre-Modification (1) Post-Modification (1) Total Difference Number of Pre-Modification ( 1) Post-Modification (1) Total Difference Commercial real estate Principal deferral 1 $ 4,721 $ 2,270 $ (2,451 ) 2 $ 2,851 $ 1,841 $ (1,010 ) Chapter 7 bankruptcy (2) 1 709 681 (28 ) — — — — Interest rate reduction 1 250 248 (2 ) — — — — Maturity date extension — — — — 1 264 260 (4 ) Commercial and industrial Principal forgiveness — — — — 1 400 273 (127 ) Principal deferral 5 985 985 — 6 661 363 (298 ) Chapter 7 bankruptcy (2) — — — — 1 3 — (3 ) Maturity date extension 5 4,860 4,891 31 1 780 720 (60 ) Commercial Construction Principal deferral — — — — 1 104 — (104 ) Maturity date extension 5 1,357 1,302 (55 ) 2 813 812 (1 ) Residential mortgage Principal deferral 1 3,273 3,273 — — — — — Chapter 7 bankruptcy (2) 7 439 433 (6 ) 2 74 74 — Maturity date extension 1 483 483 — 1 180 180 — Maturity date extension and interest rate reduction 1 280 280 — 2 225 229 4 Home equity Principal deferral 1 47 46 (1 ) — — — — Chapter 7 bankruptcy (2) 16 481 470 (11 ) 17 428 389 (39 ) Maturity date extension and interest rate reduction 1 130 128 (2 ) 2 138 138 — Maturity date extension 4 274 272 (2 ) 1 71 70 (1 ) Installment and other consumer Chapter 7 bankruptcy (2) 2 16 13 (3 ) 1 9 4 (5 ) Total by Concession Type Principal forgiveness — $ — $ — $ — 1 $ 400 $ 273 $ (127 ) Principal deferral 8 9,026 6,574 (2,452 ) 9 3,616 2,204 (1,412 ) Chapter 7 bankruptcy (2) 26 1,645 1,597 (48 ) 21 514 467 (47 ) Interest rate reduction 1 250 248 (2 ) — Maturity date extension and interest rate reduction 2 410 408 (2 ) 4 363 367 4 Maturity date extension 15 6,974 6,948 (26 ) 6 2,108 2,042 (66 ) Total 52 $ 18,305 $ 15,775 $ (2,530 ) 41 $ 7,001 $ 5,353 $ (1,648 ) (1) Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end. (2) Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.
Summary of Nonperforming Assets of Defaulted TDRs	The following tables present a summary of TDRs which defaulted during the periods presented that had been restructured within the last 12 months prior to defaulting: Defaulted TDRs Three Months Ended September 30, Nine Months Ended September 30, 2016 2015 2016 2015 (dollars in thousands) Number of Defaults Recorded Investment Number of Defaults Recorded Investment Number of Recorded Number of Recorded Commercial real estate — $ — — $ — — $ — — $ — Commercial and Industrial — — — — — — — — Commercial construction — — — — — — — — Residential mortgage — — — — — — 1 183 Home equity — — — — — — 3 124 Installment and other consumer — — — — — — — — Consumer construction — — — — — — — — Total — $ — — $ — — $ — 4 $ 307
Summary of Nonperforming Assets	The following table is a summary of nonperforming assets as of the dates presented: Nonperforming Assets (dollars in thousands) September 30, 2016 December 31, 2015 Nonperforming Assets Nonaccrual loans $ 25,398 $ 27,723 Nonaccrual TDRs 15,095 7,659 Total nonaccrual loans 40,493 35,382 OREO 512 354 Total Nonperforming Assets $ 41,005 $ 35,736

Allowance for Loan Losses (Tabl

Allowance for Loan Losses (Tables)	9 Months Ended
	Sep. 30, 2016
Receivables [Abstract]
Age Analysis of Past Due Loans Segregated by Class of Loans	The following tables present the age analysis of past due loans segregated by class of loans as of the dates presented: September 30, 2016 (dollars in thousands) Current 30-59 Days Past Due 60-89 Days Past Due Nonaccrual Total Past Due Total Loans Commercial real estate $ 2,413,004 $ 3,286 $ 3,323 $ 7,551 $ 14,160 $ 2,427,164 Commercial and industrial 1,327,898 3,536 973 11,890 16,399 1,344,297 Commercial construction 394,812 456 203 6,653 7,312 402,124 Residential mortgage 679,237 585 1,352 11,400 13,337 692,574 Home equity 478,389 2,321 270 2,955 5,546 483,935 Installment and other consumer 61,954 205 85 44 334 62,288 Consumer construction 5,852 — — — — 5,852 Loans held for sale 11,694 — — — — 11,694 Total $ 5,372,840 $ 10,389 $ 6,206 $ 40,493 $ 57,088 $ 5,429,928 December 31, 2015 (dollars in thousands) Current 30-59 Days Past Due 60-89 Days Past Due Nonaccrual Total Past Due Total Loans Commercial real estate $ 2,145,655 $ 11,602 $ 627 $ 8,719 $ 20,948 $ 2,166,603 Commercial and industrial 1,244,802 2,453 296 9,279 12,028 1,256,830 Commercial construction 401,084 3,517 90 8,753 12,360 413,444 Residential mortgage 631,085 1,728 930 5,629 8,287 639,372 Home equity 465,055 2,365 523 2,902 5,790 470,845 Installment and other consumer 73,486 242 111 100 453 73,939 Consumer construction 6,579 — — — — 6,579 Loans held for sale 35,179 94 48 — 142 35,321 Total $ 5,002,925 $ 22,001 $ 2,625 $ 35,382 $ 60,008 $ 5,062,933
Recorded Investment in Commercial Loan Classes by Internally Assigned Risk Ratings	The following tables present the recorded investment in commercial loan classes by internally assigned risk ratings as of the dates presented: September 30, 2016 (dollars in thousands) Commercial Real Estate % of Total Commercial and Industrial % of Total Commercial Construction % of Total Total % of Total Pass $ 2,346,848 96.7 % $ 1,253,411 93.2 % $ 375,006 93.2 % $ 3,975,265 95.2 % Special mention 30,050 1.2 % 37,079 2.8 % 14,335 3.6 % 81,464 2.0 % Substandard 50,266 2.1 % 53,807 4.0 % 12,783 3.2 % 116,856 2.8 % Total $ 2,427,164 100.0 % $ 1,344,297 100.0 % $ 402,124 100.0 % $ 4,173,585 100.0 % December 31, 2015 (dollars in thousands) Commercial Real Estate % of Total Commercial and Industrial % of Total Commercial Construction % of Total Total % of Total Pass $ 2,094,851 96.7 % $ 1,182,685 94.1 % $ 375,808 90.9 % $ 3,653,344 95.2 % Special mention 19,938 0.9 % 43,896 3.5 % 19,846 4.8 % 83,680 2.2 % Substandard 51,814 2.4 % 30,249 2.4 % 17,790 4.3 % 99,853 2.6 % Total $ 2,166,603 100.0 % $ 1,256,830 100.0 % $ 413,444 100.0 % $ 3,836,877 100.0 %
Recorded Investment in Consumer Loan Classes by Performing and Nonperforming Status	The following tables present the recorded investment in consumer loan classes by performing and nonperforming status as of the dates presented: September 30, 2016 (dollars in thousands) Residential Mortgage % of Total Home Equity % of Total Installment and other consumer % of Total Consumer Construction % of Total Total % of Total Performing $ 681,174 98.4 % $ 480,980 99.4 % $ 62,244 99.9 % $ 5,852 100.0 % $ 1,230,250 98.8 % Nonperforming 11,400 1.6 % 2,955 0.6 % 44 0.1 % — — % 14,399 1.2 % Total $ 692,574 100.0 % $ 483,935 100.0 % $ 62,288 100.0 % $ 5,852 100.0 % $ 1,244,649 100.0 % December 31, 2015 (dollars in thousands) Residential Mortgage % of Total Home Equity % of Total Installment and other consumer % of Total Consumer Construction % of Total Total % of Total Performing $ 633,743 99.1 % $ 467,943 99.4 % $ 73,839 99.8 % $ 6,579 100.0 % $ 1,182,104 99.3 % Nonperforming 5,629 0.9 % 2,902 0.6 % 100 0.2 % — — % 8,631 0.7 % Total $ 639,372 100.0 % $ 470,845 100.0 % $ 73,939 100.0 % $ 6,579 100.0 % $ 1,190,735 100.0 %
Investments in Loans Considered to be Impaired and Related Information on Impaired Loans	For the Nine Months Ended September 30, 2016 September 30, 2015 (dollars in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Without a related allowance recorded: Commercial real estate $ 7,551 $ 106 $ 14,994 $ 731 Commercial and industrial 7,447 156 9,742 131 Commercial construction 8,498 143 8,920 200 Consumer real estate 11,831 400 6,856 279 Other consumer 38 1 119 1 Total without a Related Allowance Recorded 35,365 806 40,631 1,342 With a related allowance recorded: Commercial real estate — — — — Commercial and industrial 2,492 100 1,980 42 Commercial construction — — — — Consumer real estate 29 2 121 5 Other consumer 2 — 2 — Total with a Related Allowance Recorded 2,523 102 2,103 47 Total: Commercial real estate 7,551 106 14,994 731 Commercial and industrial 9,939 256 11,722 173 Commercial construction 8,498 143 8,920 200 Consumer real estate 11,860 402 6,977 284 Other consumer 40 1 121 1 Total $ 37,888 $ 908 $ 42,734 $ 1,389 The following tables summarize investments in loans considered to be impaired and related information on those impaired loans as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Recorded Investment Unpaid Principal Balance Related Allowance Recorded Investment Unpaid Principal Balance Related Allowance Without a related allowance recorded: Commercial real estate $ 7,589 $ 7,818 $ — $ 12,661 $ 13,157 $ — Commercial and industrial 8,261 9,730 — 14,417 15,220 — Commercial construction 7,987 11,547 — 10,998 14,200 — Consumer real estate 11,731 12,434 — 6,845 7,521 — Other consumer 29 36 — 111 188 — Total without a Related Allowance Recorded 35,597 41,565 — 45,032 50,286 — With a related allowance recorded: Commercial real estate — — — — — — Commercial and industrial 2,433 2,433 2,206 — — — Commercial construction — — — 500 1,350 3 Consumer real estate 27 27 27 116 116 32 Other consumer 2 2 2 2 2 2 Total with a Related Allowance Recorded 2,462 2,462 2,235 618 1,468 37 Total: Commercial real estate 7,589 7,818 — 12,661 13,157 — Commercial and industrial 10,694 12,163 2,206 14,417 15,220 — Commercial construction 7,987 11,547 — 11,498 15,550 3 Consumer real estate 11,758 12,461 27 6,961 7,637 32 Other consumer 31 38 2 113 190 2 Total $ 38,059 $ 44,027 $ 2,235 $ 45,650 $ 51,754 $ 37 The following tables summarize investments in loans considered to be impaired and related information on those impaired loans for the periods presented: For the Three Months Ended September 30, 2016 September 30, 2015 (dollars in thousands) Average Recorded Investment Interest Income Recognized Average Recorded Investment Interest Income Recognized Without a related allowance recorded: Commercial real estate $ 7,582 $ 38 $ 14,101 $ 352 Commercial and industrial 7,326 52 8,993 44 Commercial construction 8,039 49 11,034 67 Consumer real estate 11,686 159 6,829 92 Other consumer 32 — 183 — Total without a Related Allowance Recorded 34,665 298 41,140 555 With a related allowance recorded: Commercial real estate — — — — Commercial and industrial 2,437 37 1,977 7 Commercial construction — — — — Consumer real estate 28 — 119 2 Other consumer 2 — 2 — Total with a Related Allowance Recorded 2,467 37 2,098 9 Total: Commercial real estate 7,582 38 14,101 352 Commercial and industrial 9,763 89 10,970 51 Commercial construction 8,039 49 11,034 67 Consumer real estate 11,714 159 6,948 94 Other consumer 34 — 185 — Total $ 37,132 $ 335 $ 43,238 $ 564
Summary of Allowance for Loan Losses	The following tables detail activity in the ALL for the periods presented: Three Months Ended September 30, 2016 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 15,978 $ 14,771 $ 11,701 $ 8,418 $ 1,345 $ 52,213 Charge-offs (93 ) (414 ) (163 ) (369 ) (461 ) (1,500 ) Recoveries 264 169 17 44 70 564 Net (Charge-offs)/ Recoveries 171 (245 ) (146 ) (325 ) (391 ) (936 ) Provision for loan losses 4,244 (2,232 ) 1,356 (1,760 ) 908 2,516 Balance at End of Period $ 20,393 $ 12,294 $ 12,911 $ 6,333 $ 1,862 $ 53,793 Three Months Ended September 30, 2015 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 19,018 $ 13,308 $ 7,671 $ 7,027 $ 1,790 $ 48,814 Charge-offs (2,361 ) (1,121 ) (1,247 ) (445 ) (467 ) (5,641 ) Recoveries 2,896 272 129 132 99 3,528 Net (Charge-offs)/ Recoveries 535 (849 ) (1,118 ) (313 ) (368 ) (2,113 ) Provision for loan losses (2,575 ) 12 4,983 302 484 3,206 Balance at End of Period $ 16,978 $ 12,471 $ 11,536 $ 7,016 $ 1,906 $ 49,907 Nine Months Ended September 30, 2016 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 15,043 $ 10,853 $ 12,625 $ 8,400 $ 1,226 $ 48,147 Charge-offs (1,808 ) (3,244 ) (1,108 ) (891 ) (1,572 ) (8,623 ) Recoveries 662 589 20 342 277 1,890 Net (Charge-offs)/Recoveries (1,146 ) (2,655 ) (1,088 ) (549 ) (1,295 ) (6,733 ) Provision for loan losses 6,496 4,096 1,374 (1,518 ) 1,931 12,379 Balance at End of Period $ 20,393 $ 12,294 $ 12,911 $ 6,333 $ 1,862 $ 53,793 Nine Months Ended September 30, 2015 (dollars in thousands) Commercial Real Estate Commercial and Industrial Commercial Construction Consumer Real Estate Other Consumer Total Loans Balance at beginning of period $ 20,164 $ 13,668 $ 6,093 $ 6,333 $ 1,653 $ 47,911 Charge-offs (2,738 ) (2,819 ) (1,247 ) (997 ) (1,046 ) (8,847 ) Recoveries 3,072 475 132 379 312 4,370 Net (Charge-offs)/Recoveries 334 (2,344 ) (1,115 ) (618 ) (734 ) (4,477 ) Provision for loan losses (3,520 ) 1,147 6,558 1,301 987 6,473 Balance at End of Period $ 16,978 $ 12,471 $ 11,536 $ 7,016 $ 1,906 $ 49,907
Summary of Allowance for Loan Losses and Recorded Investments	The following tables present the ALL and recorded investments in loans by category as of the periods presented: September 30, 2016 Allowance for Loan Losses Portfolio Loans (dollars in thousands) Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Commercial real estate $ — $ 20,393 $ 20,393 $ 7,589 $ 2,419,575 $ 2,427,164 Commercial and industrial 2,206 10,088 12,294 10,694 1,333,603 1,344,297 Commercial construction — 12,911 12,911 7,987 394,137 402,124 Consumer real estate 27 6,306 6,333 11,758 1,170,603 1,182,361 Other consumer 2 1,860 1,862 31 62,257 62,288 Total $ 2,235 $ 51,558 $ 53,793 $ 38,059 $ 5,380,175 $ 5,418,234 December 31, 2015 Allowance for Loan Losses Portfolio Loans (dollars in thousands) Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Individually Evaluated for Impairment Collectively Evaluated for Impairment Total Commercial real estate $ — $ 15,043 $ 15,043 $ 12,661 $ 2,153,942 $ 2,166,603 Commercial and industrial — 10,853 10,853 14,417 1,242,413 1,256,830 Commercial construction 3 12,622 12,625 11,498 401,946 413,444 Consumer real estate 32 8,368 8,400 6,961 1,109,835 1,116,796 Other consumer 2 1,224 1,226 113 73,826 73,939 Total $ 37 $ 48,110 $ 48,147 $ 45,650 $ 4,981,962 $ 5,027,612

Derivative Instruments and He29

Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Value of Derivative Assets and Derivative Liabilities	The following table indicates the amounts representing the value of derivative assets and derivative liabilities as of the dates presented: Derivatives (included in Other Assets) Derivatives (included in Other Liabilities) (dollars in thousands) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Derivatives not Designated as Hedging Instruments: Interest Rate Swap Contracts- Commercial Loans Fair value $ 15,255 $ 11,295 $ 15,202 $ 11,276 Notional amount 264,655 245,595 264,655 245,595 Collateral posted — — 14,542 12,753 Interest Rate Lock Commitments- Mortgage Loans Fair value 739 261 — — Notional amount 21,699 9,894 — — Forward Sale Contracts- Mortgage Loans Fair value — — 98 5 Notional amount $ — $ — $ 16,892 $ 9,800
Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities	The following table indicates the gross amounts of commercial loan swap derivative assets and derivative liabilities, the amounts offset and the carrying values in the Consolidated Balance Sheets as of the dates presented: Derivatives (included in Other Assets) Derivatives (included in Other Liabilities) (dollars in thousands) September 30, 2016 December 31, 2015 September 30, 2016 December 31, 2015 Derivatives not Designated as Hedging Instruments: Gross amounts recognized $ 15,255 $ 11,295 $ 15,202 $ 11,276 Gross amounts offset — — — — Net amounts presented in the Consolidated Balance Sheets 15,255 11,295 15,202 11,276 Gross amounts not offset (1) — — (14,542 ) (12,573 ) Net Amount $ 15,255 $ 11,295 $ 660 $ (1,297 ) (1) Amounts represent posted collateral.
Amount of Gain or Loss Recognized in Income on Derivatives	The following table indicates the gain or loss recognized in income on derivatives for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Derivatives not Designated as Hedging Instruments Interest rate swap contracts—commercial loans $ (87 ) $ 29 $ 34 $ 20 Interest rate lock commitments—mortgage loans 97 208 478 339 Forward sale contracts—mortgage loans 106 (143 ) (93 ) (69 ) Total Derivatives Gain $ 116 $ 94 $ 419 $ 290

Borrowings (Tables)

Borrowings (Tables)	9 Months Ended
	Sep. 30, 2016
Debt Disclosure [Abstract]
Summary of Information Pertaining to Borrowings	Information pertaining to borrowings is summarized in the table below as of the dates presented: September 30, 2016 December 31, 2015 (dollars in thousands) Balance Weighted Average Rate Balance Weighted Average Rate Short-term borrowings Securities sold under repurchase agreements $ 40,949 0.01 % $ 62,086 0.01 % Short-term borrowings 565,000 0.60 % 356,000 0.52 % Total short-term borrowings 605,949 0.56 % 418,086 0.44 % Long-term borrowings Other long-term borrowings 15,303 2.91 % 117,043 0.81 % Junior subordinated debt securities 45,619 3.11 % 45,619 2.89 % Total long-term borrowings 60,922 3.06 % 162,662 1.39 % Total Borrowings $ 666,871 0.79 % $ 580,748 0.71 %

Commitments and Contingencies (

Commitments and Contingencies (Tables)	9 Months Ended
	Sep. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Letters of Credit	The following table sets forth our commitments and letters of credit as of the dates presented: (dollars in thousands) September 30, 2016 December 31, 2015 Commitments to extend credit $ 1,546,164 $ 1,619,854 Standby letters of credit 80,181 97,676 Total $ 1,626,345 $ 1,717,530

Other Comprehensive Income (Tab

Other Comprehensive Income (Tables)	9 Months Ended
	Sep. 30, 2016
Equity [Abstract]
Tax Effects of Components of Other Comprehensive Income	The following table represents the change in components of other comprehensive income (loss) for the periods presented, net of tax effects. Three Months Ended September 30, 2016 Three Months Ended September 30, 2015 (dollars in thousands) Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Change in net unrealized gains/(losses) on securities available-for-sale $ (1,921 ) $ 672 $ (1,249 ) $ 5,177 $ (1,812 ) $ 3,365 Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income (1) — — — — — — Adjustment to funded status of employee benefit plans 544 (190 ) 354 647 (227 ) 420 Other Comprehensive Income/(Loss) $ (1,377 ) $ 482 $ (895 ) $ 5,824 $ (2,039 ) $ 3,785 (1) Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income/(loss) and have affected certain lines in the Consolidated Statements of Comprehensive Income as follows; the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income. Nine Months Ended September 30, 2016 Nine Months Ended September 30, 2015 (dollars in thousands) Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Pre-Tax Amount Tax (Expense) Benefit Net of Tax Amount Change in net unrealized gains/(losses) on securities available-for-sale $ 11,748 $ (4,112 ) $ 7,636 $ 4,288 $ (1,501 ) $ 2,787 Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income (1) — — — 34 (12 ) 22 Adjustment to funded status of employee benefit plans 4,889 (1,711 ) 3,178 1,839 (551 ) 1,288 Other Comprehensive Income $ 16,637 $ (5,823 ) $ 10,814 $ 6,161 $ (2,064 ) $ 4,097 (1) Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.

Employee Benefits (Tables)

Employee Benefits (Tables)	9 Months Ended
	Sep. 30, 2016
Compensation and Retirement Disclosure [Abstract]
Components of Net Periodic Pension Cost and Other Changes in Plan Assets and Benefit	The following table summarizes the components of net periodic pension cost for the periods presented: Three Months Ended September 30, Nine Months Ended September 30, (dollars in thousands) 2016 2015 2016 2015 Components of Net Periodic Pension Cost Service cost—benefits earned during the period $ (6 ) $ 606 $ 469 $ 1,951 Interest cost on projected benefit obligation 1,099 1,120 3,200 3,319 Expected return on plan assets (1,444 ) (1,772 ) (4,337 ) (5,385 ) Amortization of prior service credit 29 (34 ) (41 ) (104 ) Recognized net actuarial loss 638 586 1,708 1,521 Net Periodic Pension Expense $ 316 $ 506 $ 999 $ 1,302

Segments (Tables)

Segments (Tables)	9 Months Ended
	Sep. 30, 2016
Segment Reporting [Abstract]
Total Assets by Reportable Operating Segment	The following table represents total assets by reportable operating segment as of the dates presented: (dollars in thousands) September 30, 2016 December 31, 2015 Community Banking $ 6,706,383 $ 6,305,046 Insurance 8,050 9,619 Wealth Management 3,772 3,689 Total Assets $ 6,718,205 $ 6,318,354
Financial Information of Segments	The following tables provide financial information for our three operating segments for the three and nine month periods ended September 30, 2016 and 2015 . The financial results of the business segments include allocations for shared services based on an internal analysis that supports line of business and branch performance measurements. Shared services include expenses such as employee benefits, occupancy expense, computer support and other corporate overhead. Even with these allocations, the financial results are not necessarily indicative of the business segments’ financial condition and results of operations as if they existed as independent entities. The information provided under the caption “Eliminations” represents operations not considered to be reportable segments and/or general operating expenses and eliminations and adjustments, which are necessary for purposes of reconciling to the Consolidated Financial Statements. Three Months Ended September 30, 2016 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 57,804 $ 1 $ 98 $ (95 ) $ 57,808 Interest expense 6,433 — — (80 ) 6,353 Net interest income 51,371 1 98 (15 ) 51,455 Provision for loan losses 2,516 — — — 2,516 Noninterest income 9,548 1,119 2,563 218 13,448 Noninterest expense 28,889 1,097 2,591 203 32,780 Depreciation expense 1,269 11 4 — 1,284 Amortization of intangible assets 359 12 4 — 375 Provision for income taxes 7,347 (1 ) 21 — 7,367 Net Income $ 20,539 $ 1 $ 41 $ — $ 20,581 Three Months Ended September 30, 2015 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 53,625 $ 1 $ 108 $ (65 ) $ 53,669 Interest expense 4,200 — — (127 ) 4,073 Net interest income 49,425 1 108 62 49,596 Provision for loan losses 3,206 — — — 3,206 Noninterest income 8,651 1,197 2,806 (173 ) 12,481 Noninterest expense 28,941 1,098 2,210 (111 ) 32,138 Depreciation expense 1,192 13 6 — 1,211 Amortization of intangible assets 460 13 7 — 480 Provision for income taxes 6,139 26 242 — 6,407 Net Income $ 18,138 $ 48 $ 449 $ — $ 18,635 Nine Months Ended September 30, 2016 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 168,661 $ 2 $ 343 $ (328 ) $ 168,678 Interest expense 18,085 — — (208 ) 17,877 Net interest income 150,576 2 343 (120 ) 150,801 Provision for loan losses 12,379 — — — 12,379 Noninterest income 28,468 3,836 7,936 1,473 41,713 Noninterest expense 90,499 3,455 7,334 1,353 102,641 Depreciation expense 3,678 33 12 — 3,723 Amortization of intangible assets 1,189 37 17 — 1,243 Provision for income taxes 18,364 110 321 — 18,795 Net Income $ 52,935 $ 203 $ 595 $ — $ 53,733 Nine Months Ended September 30, 2015 (dollars in thousands) Community Banking Insurance Wealth Management Eliminations Consolidated Interest income $ 150,108 $ 2 $ 406 $ (321 ) $ 150,195 Interest expense 12,144 — — (615 ) 11,529 Net interest income 137,964 2 406 294 138,666 Provision for loan losses 6,473 — — — 6,473 Noninterest income 25,056 4,079 8,639 174 37,948 Noninterest expense 87,542 3,288 6,716 468 98,014 Depreciation expense 3,482 39 19 — 3,540 Amortization of intangible assets 1,283 38 24 — 1,345 Provision for income taxes 16,534 250 800 — 17,584 Net Income $ 47,706 $ 466 $ 1,486 $ — $ 49,658

Basis of Presentation - Additio

Basis of Presentation - Additional Information (Details)	Sep. 30, 2016
Minimum
Schedule of Equity Method Investments [Line Items]
Percentage of outstanding common stock of investees accounted for using equity method of accounting	20.00%
Maximum
Schedule of Equity Method Investments [Line Items]
Percentage of outstanding common stock of investees accounted for using equity method of accounting	50.00%

Business Combinations - Additio

Business Combinations - Additional Information (Details) - USD ($)	Mar. 04, 2015	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Mar. 04, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill		$ 291,670,000		$ 291,670,000			$ 291,764,000
Merger related expenses		0	$ 0	0	$ 3,167,000
Integrity Bancshares, Inc.
Business Acquisition [Line Items]
Business acquisition, percentage of voting interests acquired	100.00%
Business acquisition, cash per share offered in exchange of share (in dollars per share)	$ 52.50
Shares of S&T offered for each share of Integrity (shares)	2.0627
Fair value of total consideration	$ 172,000,000					$ 171,979,000
Cash	$ 29,500,000					29,510,000
S&T common shares issued (shares)	4,933,115
S&T common shares issued, fair value (in dollars per share)	$ 28.88
Purchase accounting adjustments, increase to goodwill						1,100,000
Purchase accounting adjustments, decrease to deferred taxes						300,000
Goodwill						115,850,000
Carryover of allowance for loan losses	$ 0
Fair value of loans acquired	788,700,000					788,687,000
Discount on loans acquired	14,800,000
Merger related expenses		$ 0	$ 0	$ 0	$ 3,200,000
Integrity Bancshares, Inc. | Commercial and Industrial
Business Acquisition [Line Items]
Fair value of loans acquired	184,200,000
Integrity Bancshares, Inc. | Commercial Real Estate
Business Acquisition [Line Items]
Fair value of loans acquired	331,600,000
Integrity Bancshares, Inc. | Commercial Construction
Business Acquisition [Line Items]
Fair value of loans acquired	92,400,000
Integrity Bancshares, Inc. | Residential Mortgage
Business Acquisition [Line Items]
Fair value of loans acquired	116,900,000
Integrity Bancshares, Inc. | Home Equity
Business Acquisition [Line Items]
Fair value of loans acquired	25,600,000
Integrity Bancshares, Inc. | Installment and Other Consumer
Business Acquisition [Line Items]
Fair value of loans acquired	36,100,000
Integrity Bancshares, Inc. | Consumer Construction
Business Acquisition [Line Items]
Fair value of loans acquired	$ 1,900,000
Integrity Bancshares, Inc. | Land
Business Acquisition [Line Items]
Purchase accounting adjustments, decrease to land						$ 800,000

Business Combinations - Conside

Business Combinations - Consideration, Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 04, 2015	Mar. 04, 2016	Sep. 30, 2016	Dec. 31, 2015
Fair Value of Liabilities Assumed
Goodwill			$ 291,670	$ 291,764
Integrity Bancshares, Inc.
Business Acquisition [Line Items]
Cash	$ 29,500	$ 29,510
Common stock		142,469
Fair Value of Total Consideration	172,000	171,979
Fair Value of Assets Acquired
Cash and cash equivalents		13,163
Securities and other investments		11,502
Loans	$ 788,700	788,687
Bank owned life insurance		15,974
Premises and equipment		10,855
Core deposit intangible		5,713
Other assets		19,088
Total Assets Acquired		864,982
Fair Value of Liabilities Assumed
Deposits		722,308
Borrowings		82,286
Other liabilities		4,259
Total Liabilities Assumed		808,853
Total Fair Value of Identifiable Net Assets		56,129
Goodwill		$ 115,850

Earnings Per Share - Reconciles

Earnings Per Share - Reconciles Numerators and Denominators of Basic Earnings Per Share with Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Numerator for Earnings per Share-Basic:
Net income	$ 20,581	$ 18,635	$ 53,733	$ 49,658
Less: Income allocated to participating shares	68	81	167	204
Net Income Allocated to Shareholders	20,513	18,554	53,566	49,454
Net Income (Loss) Available to Common Stockholders, Diluted	$ 20,581	$ 18,635	$ 53,733	$ 49,658
Denominators:
Weighted Average Shares Outstanding-Basic	34,687,487	34,660,007	34,674,453	33,527,549
Add: Potentially dilutive shares	81,018	32,985	72,724	33,980
Denominator for Treasury Stock Method-Diluted (in shares)	34,768,505	34,692,992	34,747,177	33,561,529
Weighted Average Shares Outstanding-Basic	34,687,487	34,660,007	34,674,453	33,527,549
Add: Average participating shares outstanding	114,746	151,972	108,414	138,441
Denominator for Two-Class Method-Diluted (in shares)	34,802,233	34,811,979	34,782,867	33,665,990
Earnings per share—basic (in dollars per share)	$ 0.59	$ 0.54	$ 1.55	$ 1.48
Earnings per share—diluted (in dollars per share)	0.59	0.54	1.54	1.48
Anti-dilutive warrants - exercise price (in dollars per share)	$ 31.53	$ 31,530	$ 31.53	$ 31,530
Warrants
Denominators:
Anti-dilutive excluded from potentially dilutive shares	517,012	517,012	517,012	517,012
Stock Options
Denominators:
Anti-dilutive excluded from potentially dilutive shares	0	155,500	0	155,500
Restricted Stock
Denominators:
Anti-dilutive excluded from potentially dilutive shares	146,695	118,987	134,983	104,461

Fair Value Measurement - Assets

Fair Value Measurement - Assets and Liabilities Measured at Fair Value on Recurring Basis (Detail) - USD ($)	Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Transfers between Level 1 to Level 2	$ 0
ASSETS
Total securities available-for-sale	671,128,000	$ 660,963,000
US Treasury Securities
ASSETS
Total securities available-for-sale	15,056,000	14,941,000
Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	250,924,000	263,303,000
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	137,460,000	128,835,000
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	36,285,000	40,125,000
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	88,499,000	69,204,000
Obligations of States and Political Subdivisions
ASSETS
Total securities available-for-sale	132,536,000	134,886,000
Marketable Equity Securities
ASSETS
Total securities available-for-sale	10,368,000	9,669,000
Fair Value Measurements, Recurring
ASSETS
Total securities available-for-sale	671,128,000	660,963,000
Trading securities held in a Rabbi Trust	4,312,000	4,021,000
Total securities	675,440,000	664,984,000
Total Assets	691,434,000	676,540,000
LIABILITIES
Total Liabilities	15,300,000	11,281,000
Fair Value Measurements, Recurring | Interest Rate Swaps
ASSETS
Derivative financial assets	15,255,000	11,295,000
LIABILITIES
Derivative financial liabilities	15,202,000	11,276,000
Fair Value Measurements, Recurring | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	739,000	261,000
Fair Value Measurements, Recurring | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	98,000	5,000
Fair Value Measurements, Recurring | US Treasury Securities
ASSETS
Total securities available-for-sale	15,056,000	14,941,000
Fair Value Measurements, Recurring | Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	250,924,000	263,303,000
Fair Value Measurements, Recurring | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	137,460,000	128,835,000
Fair Value Measurements, Recurring | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	36,285,000	40,125,000
Fair Value Measurements, Recurring | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	88,499,000	69,204,000
Fair Value Measurements, Recurring | Obligations of States and Political Subdivisions
ASSETS
Total securities available-for-sale	132,536,000	134,886,000
Fair Value Measurements, Recurring | Marketable Equity Securities
ASSETS
Total securities available-for-sale	10,368,000	9,669,000
Fair Value Measurements, Recurring | Level 1
ASSETS
Total securities available-for-sale	0	0
Trading securities held in a Rabbi Trust	4,312,000	4,021,000
Total securities	4,312,000	4,021,000
Total Assets	4,312,000	4,021,000
LIABILITIES
Total Liabilities	0	0
Fair Value Measurements, Recurring | Level 1 | Interest Rate Swaps
ASSETS
Derivative financial assets	0	0
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring | Level 1 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	0	0
Fair Value Measurements, Recurring | Level 1 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring | Level 1 | US Treasury Securities
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 1 | Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 1 | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 1 | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 1 | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 1 | Obligations of States and Political Subdivisions
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 1 | Marketable Equity Securities
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 2
ASSETS
Total securities available-for-sale	671,128,000	660,963,000
Trading securities held in a Rabbi Trust	0	0
Total securities	671,128,000	660,963,000
Total Assets	687,122,000	672,519,000
LIABILITIES
Total Liabilities	15,300,000	11,281,000
Fair Value Measurements, Recurring | Level 2 | Interest Rate Swaps
ASSETS
Derivative financial assets	15,255,000	11,295,000
LIABILITIES
Derivative financial liabilities	15,202,000	11,276,000
Fair Value Measurements, Recurring | Level 2 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	739,000	261,000
Fair Value Measurements, Recurring | Level 2 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	98,000	5,000
Fair Value Measurements, Recurring | Level 2 | US Treasury Securities
ASSETS
Total securities available-for-sale	15,056,000	14,941,000
Fair Value Measurements, Recurring | Level 2 | Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	250,924,000	263,303,000
Fair Value Measurements, Recurring | Level 2 | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	137,460,000	128,835,000
Fair Value Measurements, Recurring | Level 2 | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	36,285,000	40,125,000
Fair Value Measurements, Recurring | Level 2 | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	88,499,000	69,204,000
Fair Value Measurements, Recurring | Level 2 | Obligations of States and Political Subdivisions
ASSETS
Total securities available-for-sale	132,536,000	134,886,000
Fair Value Measurements, Recurring | Level 2 | Marketable Equity Securities
ASSETS
Total securities available-for-sale	10,368,000	9,669,000
Fair Value Measurements, Recurring | Level 3
ASSETS
Total securities available-for-sale	0	0
Trading securities held in a Rabbi Trust	0	0
Total securities	0	0
Total Assets	0	0
LIABILITIES
Total Liabilities	0	0
Fair Value Measurements, Recurring | Level 3 | Interest Rate Swaps
ASSETS
Derivative financial assets	0	0
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring | Level 3 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	0	0
Fair Value Measurements, Recurring | Level 3 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	0	0
Fair Value Measurements, Recurring | Level 3 | US Treasury Securities
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 3 | Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 3 | Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 3 | Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 3 | Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 3 | Obligations of States and Political Subdivisions
ASSETS
Total securities available-for-sale	0	0
Fair Value Measurements, Recurring | Level 3 | Marketable Equity Securities
ASSETS
Total securities available-for-sale	$ 0	$ 0

Fair Value Measurement - Asse40

Fair Value Measurement - Assets Measured at Estimated Fair Value on Nonrecurring Basis by Fair Value Hierarchy (Detail) - Fair Value, Measurements, Nonrecurring - USD ($)		Sep. 30, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Liabilities measured at fair value on a nonrecurring basis		$ 0	$ 0
ASSETS
Impaired loans	[1]	9,000,000	9,373,000
Other real estate owned	[1]	181,000	158,000
Mortgage servicing rights	[1]	3,253,000	3,396,000
Total Assets	[1]	12,434,000	12,927,000
Level 1
ASSETS
Impaired loans	[1]	0	0
Other real estate owned	[1]	0	0
Mortgage servicing rights	[1]	0	0
Total Assets	[1]	0	0
Level 2
ASSETS
Impaired loans	[1]	0	0
Other real estate owned	[1]	0	0
Mortgage servicing rights	[1]	0	0
Total Assets	[1]	0	0
Level 3
ASSETS
Impaired loans	[1]	9,000,000	9,373,000
Other real estate owned	[1]	181,000	158,000
Mortgage servicing rights	[1]	3,253,000	3,396,000
Total Assets	[1]	$ 12,434,000	$ 12,927,000
[1]	This table represents only the nonrecurring items that are recorded at fair value in our financial statements.

Fair Value Measurement - Carryi

Fair Value Measurement - Carrying Values and Fair Values of Financial Instruments (Detail) - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
ASSETS
Securities available-for-sale		$ 671,128	$ 660,963
FHLB and other restricted stock		28,331	23,032
LIABILITIES
Junior subordinated debt securities		45,619	45,619
Carrying Value
ASSETS
Cash and due from banks, including interest-bearing deposits	[1]	125,163	99,399
Securities available-for-sale	[1]	671,128	660,963
Loans held for sale	[1]	11,695	35,321
Portfolio loans, net of unearned income	[1]	5,418,234	5,027,612
Bank owned life insurance	[1]	71,523	70,175
FHLB and other restricted stock	[1]	28,331	23,032
Trading securities held in a Rabbi Trust	[1]	4,312	4,021
Mortgage servicing rights	[1]	3,252	3,237
LIABILITIES
Deposits	[1]	5,145,431	4,876,611
Securities sold under repurchase agreements	[1]	40,949	62,086
Short-term borrowings	[1]	565,000	356,000
Long-term borrowings	[1]	15,303	117,043
Junior subordinated debt securities	[1]	45,619	45,619
Carrying Value | Interest Rate Swaps
ASSETS
Derivative financial assets	[1]	15,255	11,295
LIABILITIES
Derivative financial liabilities	[1]	15,202	11,276
Carrying Value | Interest Rate Lock Commitments
ASSETS
Derivative financial assets	[1]	739	261
Carrying Value | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities	[1]	98	5
Fair Value Measurements
ASSETS
Cash and due from banks, including interest-bearing deposits		125,163	99,399
Securities available-for-sale		671,128	660,963
Loans held for sale		12,176	35,500
Portfolio loans, net of unearned income		5,406,298	5,001,004
Bank owned life insurance		71,523	70,175
FHLB and other restricted stock		28,331	23,032
Trading securities held in a Rabbi Trust		4,312	4,021
Mortgage servicing rights		3,253	3,396
LIABILITIES
Deposits		5,151,031	4,881,718
Securities sold under repurchase agreements		40,949	62,086
Short-term borrowings		565,000	356,000
Long-term borrowings		16,111	117,859
Junior subordinated debt securities		45,619	45,619
Fair Value Measurements | Interest Rate Swaps
ASSETS
Derivative financial assets		15,255	11,295
LIABILITIES
Derivative financial liabilities		15,202	11,276
Fair Value Measurements | Interest Rate Lock Commitments
ASSETS
Derivative financial assets		739	261
Fair Value Measurements | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities		98	5
Fair Value Measurements | Level 1
ASSETS
Cash and due from banks, including interest-bearing deposits		125,163	99,399
Securities available-for-sale		0	0
Loans held for sale		0	0
Portfolio loans, net of unearned income		0	0
Bank owned life insurance		0	0
FHLB and other restricted stock		0	0
Trading securities held in a Rabbi Trust		4,312	4,021
Mortgage servicing rights		0	0
LIABILITIES
Deposits		0	0
Securities sold under repurchase agreements		0	0
Short-term borrowings		0	0
Long-term borrowings		0	0
Junior subordinated debt securities		0	0
Fair Value Measurements | Level 1 | Interest Rate Swaps
ASSETS
Derivative financial assets		0	0
LIABILITIES
Derivative financial liabilities		0	0
Fair Value Measurements | Level 1 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets		0	0
Fair Value Measurements | Level 1 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities		0	0
Fair Value Measurements | Level 2
ASSETS
Cash and due from banks, including interest-bearing deposits		0	0
Securities available-for-sale		671,128	660,963
Loans held for sale		0	0
Portfolio loans, net of unearned income		0	0
Bank owned life insurance		71,523	70,175
FHLB and other restricted stock		0	0
Trading securities held in a Rabbi Trust		0	0
Mortgage servicing rights		0	0
LIABILITIES
Deposits		0	0
Securities sold under repurchase agreements		0	0
Short-term borrowings		0	0
Long-term borrowings		0	0
Junior subordinated debt securities		0	0
Fair Value Measurements | Level 2 | Interest Rate Swaps
ASSETS
Derivative financial assets		15,255	11,295
LIABILITIES
Derivative financial liabilities		15,202	11,276
Fair Value Measurements | Level 2 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets		739	261
Fair Value Measurements | Level 2 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities		98	5
Fair Value Measurements | Level 3
ASSETS
Cash and due from banks, including interest-bearing deposits		0	0
Securities available-for-sale		0	0
Loans held for sale		12,176	35,500
Portfolio loans, net of unearned income		5,406,298	5,001,004
Bank owned life insurance		0	0
FHLB and other restricted stock		28,331	23,032
Trading securities held in a Rabbi Trust		0	0
Mortgage servicing rights		3,253	3,396
LIABILITIES
Deposits		5,151,031	4,881,718
Securities sold under repurchase agreements		40,949	62,086
Short-term borrowings		565,000	356,000
Long-term borrowings		16,111	117,859
Junior subordinated debt securities		45,619	45,619
Fair Value Measurements | Level 3 | Interest Rate Swaps
ASSETS
Derivative financial assets		0	0
LIABILITIES
Derivative financial liabilities		0	0
Fair Value Measurements | Level 3 | Interest Rate Lock Commitments
ASSETS
Derivative financial assets		0	0
Fair Value Measurements | Level 3 | Forward Sale Contracts
LIABILITIES
Derivative financial liabilities		$ 0	$ 0
[1]	As reported in the Consolidated Balance Sheets.

Securities Available-for-Sale -

Securities Available-for-Sale - Composition of Securities Available-for-Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 649,198	$ 650,782
Gross Unrealized Gains	21,938	11,897
Gross Unrealized Losses	(8)	(1,716)
Fair Value	671,128	660,963
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	14,944	14,914
Gross Unrealized Gains	112	27
Gross Unrealized Losses		0
Fair Value	15,056	14,941
Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	246,259	262,045
Gross Unrealized Gains	4,665	1,825
Gross Unrealized Losses	0	(567)
Fair Value	250,924	263,303
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	134,675	128,458
Gross Unrealized Gains	2,785	693
Gross Unrealized Losses	0	(316)
Fair Value	137,460	128,835
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	34,685	39,185
Gross Unrealized Gains	1,600	1,091
Gross Unrealized Losses	0	(151)
Fair Value	36,285	40,125
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	86,827	69,697
Gross Unrealized Gains	1,680	183
Gross Unrealized Losses	(8)	(676)
Fair Value	88,499	69,204
Obligations of States and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	124,229	128,904
Gross Unrealized Gains	8,307	5,988
Gross Unrealized Losses	0	(6)
Fair Value	132,536	134,886
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	641,619	643,203
Gross Unrealized Gains	19,149	9,807
Gross Unrealized Losses	(8)	(1,716)
Fair Value	660,760	651,294
Marketable Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,579	7,579
Gross Unrealized Gains	2,789	2,090
Gross Unrealized Losses	0	0
Fair Value	$ 10,368	$ 9,669

Securities Available-for-Sale43

Securities Available-for-Sale - Fair Value and Age of Gross Unrealized Losses by Investment Category (Detail) $ in Thousands	Sep. 30, 2016USD ($)security	Dec. 31, 2015USD ($)security
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	2	23
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 7,912	$ 213,997
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (8)	$ (1,302)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	3
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 24,014
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ (414)
Available-for-sale, Securities, Number of Positions | security	2	26
Available-for-sale Securities, Fair Value, Total	$ 7,912	$ 238,011
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (8)	$ (1,716)
US Treasury Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	0	0
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 0	$ 0
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions | security	0	0
Available-for-sale Securities, Fair Value, Total	$ 0	$ 0
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ 0
Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	0	10
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 0	$ 88,584
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0	$ (379)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	2
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 14,542
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ (188)
Available-for-sale, Securities, Number of Positions | security	0	12
Available-for-sale Securities, Fair Value, Total	$ 0	$ 103,126
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ (567)
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	0	6
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 0	$ 61,211
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0	$ (316)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions | security	0	6
Available-for-sale Securities, Fair Value, Total	$ 0	$ 61,211
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ (316)
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	0	1
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 0	$ 7,993
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0	$ (151)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions | security	0	1
Available-for-sale Securities, Fair Value, Total	$ 0	$ 7,993
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ (151)
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	1	5
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 7,841	$ 50,839
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (8)	$ (450)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	1
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 9,472
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ (226)
Available-for-sale, Securities, Number of Positions | security	1	6
Available-for-sale Securities, Fair Value, Total	$ 7,841	$ 60,311
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (8)	$ (676)
Obligations of States and Political Subdivisions
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	0	1
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 0	$ 5,370
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0	$ (6)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ 0
Available-for-sale, Securities, Number of Positions | security	0	1
Available-for-sale Securities, Fair Value, Total	$ 0	$ 5,370
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0	$ (6)
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	1	23
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 7,841	$ 213,997
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ (8)	$ (1,302)
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0	3
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0	$ 24,014
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0	$ (414)
Available-for-sale, Securities, Number of Positions | security	1	26
Available-for-sale Securities, Fair Value, Total	$ 7,841	$ 238,011
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ (8)	$ (1,716)
Marketable Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Available-for-sale, Securities, Less Than 12 Months, Number of Positions | security	1
Available-for-sale Securities, Less Than 12 Months, Fair Value	$ 71
Available-for-sale Securities, Less Than 12 Months, Unrealized Losses	$ 0
Available-for-sale, Securities, 12 Months or More, Number of Positions | security	0
Available-for-sale Securities, 12 Months or More, Fair Value	$ 0
Available-for-sale Securities, 12 Months or More, Unrealized Losses	$ 0
Available-for-sale, Securities, Number of Positions | security	1	0
Available-for-sale Securities, Fair Value, Total	$ 71
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	$ 0

Securities Available-for-Sale44

Securities Available-for-Sale - Additional Information (Detail) $ in Millions	Sep. 30, 2016USD ($)security	Dec. 31, 2015USD ($)security
Schedule of Available-for-sale Securities [Line Items]
Number of securities in unrealized loss position	2	26
Carrying values of pledged securities | $	$ 291.4	$ 278.4
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities in unrealized loss position	1	26
Marketable Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Number of securities in unrealized loss position	1	0

Securities Available-for-Sale45

Securities Available-for-Sale - Unrealized Gains (Losses) (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]
Total unrealized gains/(losses) on securities available for sale, Gross Unrealized Gains	$ 21,938	$ 11,897
Total unrealized gains/(losses) on securities available for sale, Gross Unrealized Losses	(8)	(1,716)
Total unrealized gains/(losses) on securities available for sale, Net Unrealized Gains/(Losses)	21,930	10,181
Income tax expense/(benefit), Gross Unrealized Gains	7,678	4,164
Income tax expense/(benefit), Gross Unrealized Losses	(3)	(601)
Income tax expense/(benefit), Net Unrealized Gains/(Losses)	7,675	3,563
Net unrealized gains/(losses), net of tax included in accumulated other comprehensive income/(loss), Gross Unrealized Gains	14,260	7,733
Net unrealized gains/(losses), net of tax included in accumulated other comprehensive income/(loss), Gross Unrealized Losses	(5)	(1,115)
Net unrealized gains/(losses), net of tax included in accumulated other comprehensive income/(loss), Net Unrealized Gains/(Losses)	$ 14,255	$ 6,618

Securities Available-for-Sale46

Securities Available-for-Sale - Amortized Cost and Fair Value of Available-for-Sale Securities (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	$ 649,198	$ 650,782
Fair Value	671,128	660,963
Obligations of the U.S. Treasury, U.S. government corporations and agencies, and obligations of states and political subdivisions
Schedule of Available-for-sale Securities [Line Items]
Due in one year or less, Amortized Cost	52,302
Due after one year through five years, Amortized Cost	216,729
Due after five years through ten years, Amortized Cost	55,893
Due after ten years, Amortized Cost	60,508
Available-for-sale Securities, Debt Maturities, Amortized Cost	385,432
Due in one year or less, Fair Value	52,439
Due after one year through five years, Fair Value	222,114
Due after five years through ten years, Fair Value	58,699
Due after ten years, Fair Value	65,264
Fair Value, Debt securities	398,516
Collateralized Mortgage Obligations of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	134,675	128,458
Fair Value	137,460	128,835
Residential Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	34,685	39,185
Fair Value	36,285	40,125
Commercial Mortgage-Backed Securities of U.S. Government Corporations and Agencies
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	86,827	69,697
Fair Value	88,499	69,204
Debt Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	641,619	643,203
Fair Value	660,760	651,294
Marketable Equity Securities
Schedule of Available-for-sale Securities [Line Items]
Amortized Cost	7,579	7,579
Fair Value	$ 10,368	$ 9,669

Loans and Loans Held for Sale -

Loans and Loans Held for Sale - Additional Information (Detail) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2016USD ($)contract	Sep. 30, 2015USD ($)	Sep. 30, 2016USD ($)contract	Sep. 30, 2015USD ($)	Dec. 31, 2015USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans, net of unearned income	$ 4,600		$ 4,600		$ 3,200
Loans, net of discount related to purchase accounting adjustments	8,200		8,200		$ 10,900
Maximum concentration of commercial real estate and commercial construction portfolio in loans (in excess of)					7.00%
Decrease in loans held for sale during the period			23,600
Gain on sale of credit card portfolio	0	$ 0	2,066	$ 0
Commitment to lend additional funds on troubled debt restructuring	$ 300		$ 300
Minimum period of loan payment defaults following restructure for TDRs to be in default			90 days
Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans modified not considered to be troubled debt restructuring | contract	12		15
Loans modified not considered to be troubled debt restructuring	$ 16,900		$ 25,600
Installment and Other Consumer
Accounts, Notes, Loans and Financing Receivable [Line Items]
Decrease in loans held for sale during the period			25,000
Gain on sale of credit card portfolio			$ 2,100
Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans modified not considered to be troubled debt restructuring | contract	1		2
Loans modified not considered to be troubled debt restructuring	$ 1,900		$ 2,500
Commercial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Percentage of commercial loans in total portfolio loans	77.00%		77.00%		76.00%
Commercial Loans	$ 4,173,585		$ 4,173,585		$ 3,836,877
Maximum concentration of commercial real estate and commercial construction portfolio in loans (in excess of)	7.00%		7.00%		7.00%
Commercial | Commercial and Industrial
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans	$ 1,344,297		$ 1,344,297		$ 1,256,830
Commercial | Commercial Real Estate and Commercial Construction
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans	$ 2,800,000		$ 2,800,000		$ 2,600,000
Combined percentage of commercial real estate and commercial construction in total commercial loans	68.00%		68.00%		67.00%
Combined percentage of commercial real estate and commercial construction in total portfolio loans	52.00%		52.00%		51.00%
Concentration risk percentage of commercial real estate and commercial construction			0.00%		0.00%
Out of market exposure of combined portfolio (percent)	5.40%		5.40%		5.80%
Percentage of total loans out-of-state excluding contiguous states	2.80%		2.80%		3.00%
Commercial | Commercial Real Estate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Commercial Loans	$ 2,427,164		$ 2,427,164		$ 2,166,603

Loans and Loans Held for Sale48

Loans and Loans Held for Sale - Composition of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Composition of the loans
Portfolio loans, net of unearned income	$ 5,418,234	$ 5,027,612
Loans held for sale	11,694	35,321
Total Loans	5,429,928	5,062,933
Commercial and Industrial
Composition of the loans
Portfolio loans, net of unearned income	1,344,297	1,256,830
Total Loans	1,344,297	1,256,830
Commercial Real Estate
Composition of the loans
Portfolio loans, net of unearned income	2,427,164	2,166,603
Total Loans	2,427,164	2,166,603
Commercial Construction
Composition of the loans
Portfolio loans, net of unearned income	402,124	413,444
Total Loans	402,124	413,444
Residential Mortgage
Composition of the loans
Total Loans	692,574	639,372
Home Equity
Composition of the loans
Total Loans	483,935	470,845
Installment and Other Consumer
Composition of the loans
Total Loans	62,288	73,939
Commercial
Composition of the loans
Portfolio loans, net of unearned income	4,173,585	3,836,877
Commercial | Commercial and Industrial
Composition of the loans
Portfolio loans, net of unearned income	1,344,297	1,256,830
Commercial | Commercial Real Estate
Composition of the loans
Portfolio loans, net of unearned income	2,427,164	2,166,603
Commercial | Commercial Construction
Composition of the loans
Portfolio loans, net of unearned income	402,124	413,444
Consumer
Composition of the loans
Portfolio loans, net of unearned income	1,244,649	1,190,735
Consumer | Commercial Construction
Composition of the loans
Portfolio loans, net of unearned income	5,852	6,579
Consumer | Residential Mortgage
Composition of the loans
Portfolio loans, net of unearned income	692,574	639,372
Consumer | Home Equity
Composition of the loans
Portfolio loans, net of unearned income	483,935	470,845
Consumer | Installment and Other Consumer
Composition of the loans
Portfolio loans, net of unearned income	$ 62,288	$ 73,939

Loans and Loans Held for Sale49

Loans and Loans Held for Sale - Summary of Restructured Loans (Detail) $ in Thousands		3 Months Ended		9 Months Ended		12 Months Ended
		Sep. 30, 2016USD ($)tdr	Sep. 30, 2015USD ($)tdr	Sep. 30, 2016USD ($)tdr	Sep. 30, 2015USD ($)tdr	Dec. 31, 2015USD ($)
Receivables [Abstract]
Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Period Increase (Decrease)				$ 23,600
Gain on sale of credit card portfolio		$ 0	$ 0	$ 2,066	$ 0
Financing Receivable, Modifications [Line Items]
Threshold period of satisfactory performance for troubled debt restructuring to be restored to accruing status				6 months
Restructured loans	[1]	$ 5,003	$ 1,578	$ 15,775	$ 5,353
Number of troubled debt restructuring loans returned back to accruing status | tdr		0	6	0	6
Amount of troubled debt restructuring loans returned back to accruing status			$ 300		$ 300
Installment and Other Consumer
Receivables [Abstract]
Loans Receivable Held-for-sale, Reconciliation to Cash Flow, Period Increase (Decrease)				$ 25,000
Gain on sale of credit card portfolio				2,100
Financing Receivable
Financing Receivable, Modifications [Line Items]
Restructured loans				28,031		$ 31,614
Financing Receivable | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Restructured loans				7,870		7,891
Financing Receivable | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Restructured loans				3,920		10,370
Financing Receivable | Commercial Construction
Financing Receivable, Modifications [Line Items]
Restructured loans				4,452		6,278
Financing Receivable | Residential Mortgage
Financing Receivable, Modifications [Line Items]
Restructured loans				7,701		3,255
Financing Receivable | Home Equity
Financing Receivable, Modifications [Line Items]
Restructured loans				4,057		3,707
Financing Receivable | Installment and Other Consumer
Financing Receivable, Modifications [Line Items]
Restructured loans				31		113
Performing Financial Instruments
Financing Receivable, Modifications [Line Items]
Restructured loans				12,936		23,955
Performing Financial Instruments | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Restructured loans				863		6,321
Performing Financial Instruments | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Restructured loans				3,054		6,822
Performing Financial Instruments | Commercial Construction
Financing Receivable, Modifications [Line Items]
Restructured loans				3,460		5,013
Performing Financial Instruments | Residential Mortgage
Financing Receivable, Modifications [Line Items]
Restructured loans				2,453		2,590
Performing Financial Instruments | Home Equity
Financing Receivable, Modifications [Line Items]
Restructured loans				3,084		3,184
Performing Financial Instruments | Installment and Other Consumer
Financing Receivable, Modifications [Line Items]
Restructured loans				22		25
Nonperforming Financial Instruments
Financing Receivable, Modifications [Line Items]
Restructured loans				15,095		7,659
Nonperforming Financial Instruments | Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Restructured loans				7,007		1,570
Nonperforming Financial Instruments | Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Restructured loans				866		3,548
Nonperforming Financial Instruments | Commercial Construction
Financing Receivable, Modifications [Line Items]
Restructured loans				992		1,265
Nonperforming Financial Instruments | Residential Mortgage
Financing Receivable, Modifications [Line Items]
Restructured loans				5,248		665
Nonperforming Financial Instruments | Home Equity
Financing Receivable, Modifications [Line Items]
Restructured loans				973		523
Nonperforming Financial Instruments | Installment and Other Consumer
Financing Receivable, Modifications [Line Items]
Restructured loans				$ 9		$ 88
[1]	Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.

Loans and Loans Held for Sale50

Loans and Loans Held for Sale - Restructured Loans During Periods Presented (Detail) $ in Thousands		3 Months Ended				9 Months Ended
		Sep. 30, 2016USD ($)contract		Sep. 30, 2015USD ($)contract		Sep. 30, 2016USD ($)contract		Sep. 30, 2015USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		14		14		52		41
Pre-Modification Outstanding Recorded Investment	[1]	$ 4,951		$ 1,593		$ 18,305		$ 7,001
Post-Modification Outstanding Recorded Investment	[1]	5,003		1,578		15,775		5,353
Total Difference in Recorded Investment		$ 52		$ (15)		$ (2,530)		$ (1,648)
Interest rate reduction
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		1		0		1
Pre-Modification Outstanding Recorded Investment	[1]	$ 250				$ 250
Post-Modification Outstanding Recorded Investment	[1]	248		$ 0		248
Total Difference in Recorded Investment		$ (2)		$ 0		$ (2)		$ 0
Maturity date extension
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		2		4		15		6
Pre-Modification Outstanding Recorded Investment	[1]	$ 4,105		$ 1,257		$ 6,974		$ 2,108
Post-Modification Outstanding Recorded Investment	[1]	4,162		1,252		6,948		2,042
Total Difference in Recorded Investment		$ 57		$ (5)		$ (26)		$ (66)
Principal forgiveness
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						0		1
Pre-Modification Outstanding Recorded Investment	[1]					$ 0		$ 400
Post-Modification Outstanding Recorded Investment	[1]					0		273
Total Difference in Recorded Investment						$ 0		$ (127)
Principal deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						8		9
Pre-Modification Outstanding Recorded Investment	[1]					$ 9,026		$ 3,616
Post-Modification Outstanding Recorded Investment	[1]					6,574		2,204
Total Difference in Recorded Investment						$ (2,452)		$ (1,412)
Chapter 7 bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | contract	[2]	10		8		26		21
Pre-Modification Outstanding Recorded Investment	[1],[2]	$ 316		$ 198		$ 1,645		$ 514
Post-Modification Outstanding Recorded Investment	[1],[2]	313		188		1,597		467
Total Difference in Recorded Investment	[2]	$ (3)		$ (10)		$ (48)		$ (47)
Maturity date extension and interest rate reduction
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		1		2		2		4
Pre-Modification Outstanding Recorded Investment	[1]	$ 280		$ 138		$ 410		$ 363
Post-Modification Outstanding Recorded Investment	[1]	280		138		408		367
Total Difference in Recorded Investment		$ 0		$ 0		$ (2)		$ 4
Commercial and Industrial | Maturity date extension
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		2		0		5		1
Pre-Modification Outstanding Recorded Investment	[1]	$ 4,105		$ 0		$ 4,860		$ 780
Post-Modification Outstanding Recorded Investment	[1]	4,162		0		4,891		720
Total Difference in Recorded Investment		$ 57		$ 0		$ 31		$ (60)
Commercial and Industrial | Principal forgiveness
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						0		1
Pre-Modification Outstanding Recorded Investment	[1]					$ 0		$ 400
Post-Modification Outstanding Recorded Investment	[1]					0		273
Total Difference in Recorded Investment						$ 0		$ (127)
Commercial and Industrial | Principal deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						5		6
Pre-Modification Outstanding Recorded Investment	[1]					$ 985		$ 661
Post-Modification Outstanding Recorded Investment	[1]					985		363
Total Difference in Recorded Investment						$ 0		$ (298)
Commercial and Industrial | Chapter 7 bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | contract	[2]					0		1
Pre-Modification Outstanding Recorded Investment	[1],[2]					$ 0		$ 3
Post-Modification Outstanding Recorded Investment	[1],[2]					0		0
Total Difference in Recorded Investment	[2]					$ 0		$ (3)
Commercial Real Estate | Interest rate reduction
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		1		0		1		0
Pre-Modification Outstanding Recorded Investment		$ 250	[1]	$ 0	[1]	$ 250	[1]	$ 0
Post-Modification Outstanding Recorded Investment		248	[1]	0	[1]	248	[1]	0
Total Difference in Recorded Investment		$ (2)		$ 0		$ (2)		$ 0
Commercial Real Estate | Maturity date extension
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		0		1		0		1
Pre-Modification Outstanding Recorded Investment	[1]	$ 0		$ 264		$ 0		$ 264
Post-Modification Outstanding Recorded Investment	[1]	0		260		0		260
Total Difference in Recorded Investment		$ 0		$ (4)		$ 0		$ (4)
Commercial Real Estate | Principal deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						1		2
Pre-Modification Outstanding Recorded Investment	[1]					$ 4,721		$ 2,851
Post-Modification Outstanding Recorded Investment	[1]					2,270		1,841
Total Difference in Recorded Investment						$ (2,451)		$ (1,010)
Commercial Real Estate | Chapter 7 bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | contract	[2]					1		0
Pre-Modification Outstanding Recorded Investment	[1],[2]					$ 709		$ 0
Post-Modification Outstanding Recorded Investment	[1],[2]					681		0
Total Difference in Recorded Investment	[2]					$ (28)		$ 0
Commercial Construction | Maturity date extension
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		0		2		5		2
Pre-Modification Outstanding Recorded Investment	[1]	$ 0		$ 813		$ 1,357		$ 813
Post-Modification Outstanding Recorded Investment	[1]	0		812		1,302		812
Total Difference in Recorded Investment		$ 0		$ (1)		$ (55)		$ (1)
Commercial Construction | Principal deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						0		1
Pre-Modification Outstanding Recorded Investment	[1]					$ 0		$ 104
Post-Modification Outstanding Recorded Investment	[1]					0		0
Total Difference in Recorded Investment						$ 0		$ (104)
Residential Mortgage | Maturity date extension
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		0		1		1		1
Pre-Modification Outstanding Recorded Investment	[1]	$ 0		$ 180		$ 483		$ 180
Post-Modification Outstanding Recorded Investment	[1]	0		180		483		180
Total Difference in Recorded Investment		$ 0		$ 0		$ 0		$ 0
Residential Mortgage | Principal deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						1		0
Pre-Modification Outstanding Recorded Investment	[1]					$ 3,273		$ 0
Post-Modification Outstanding Recorded Investment	[1]					3,273		0
Total Difference in Recorded Investment						$ 0		$ 0
Residential Mortgage | Chapter 7 bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		3	[1]	2	[2]	7	[2]	2	[2]
Pre-Modification Outstanding Recorded Investment	[1],[2]	$ 153		$ 74		$ 439		$ 74
Post-Modification Outstanding Recorded Investment	[1],[2]	152		74		433		74
Total Difference in Recorded Investment	[2]	$ (1)		$ 0		$ (6)		$ 0
Residential Mortgage | Maturity date extension and interest rate reduction
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		1		0		1		2
Pre-Modification Outstanding Recorded Investment	[1]	$ 280		$ 0		$ 280		$ 225
Post-Modification Outstanding Recorded Investment	[1]	280		0		280		229
Total Difference in Recorded Investment		$ 0		$ 0		$ 0		$ 4
Home Equity | Maturity date extension
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						4		1
Pre-Modification Outstanding Recorded Investment	[1]					$ 274		$ 71
Post-Modification Outstanding Recorded Investment	[1]					272		70
Total Difference in Recorded Investment						$ (2)		$ (1)
Home Equity | Principal deferral
Financing Receivable, Modifications [Line Items]
Number of Loans | contract						1		0
Pre-Modification Outstanding Recorded Investment	[1]					$ 47		$ 0
Post-Modification Outstanding Recorded Investment	[1]					46		0
Total Difference in Recorded Investment						$ (1)		$ 0
Home Equity | Chapter 7 bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | contract	[2]	7		5		16		17
Pre-Modification Outstanding Recorded Investment	[1],[2]	$ 163		$ 115		$ 481		$ 428
Post-Modification Outstanding Recorded Investment	[1],[2]	161		110		470		389
Total Difference in Recorded Investment	[2]	$ (2)		$ (5)		$ (11)		$ (39)
Home Equity | Maturity date extension and interest rate reduction
Financing Receivable, Modifications [Line Items]
Number of Loans | contract		0		2		1		2
Pre-Modification Outstanding Recorded Investment	[1]	$ 0		$ 138		$ 130		$ 138
Post-Modification Outstanding Recorded Investment	[1]	0		138		128		138
Total Difference in Recorded Investment		$ 0		$ 0		$ (2)		$ 0
Installment and Other Consumer | Chapter 7 bankruptcy
Financing Receivable, Modifications [Line Items]
Number of Loans | contract	[2]			1		2		1
Pre-Modification Outstanding Recorded Investment	[1],[2]			$ 9		$ 16		$ 9
Post-Modification Outstanding Recorded Investment	[1],[2]			4		13		4
Total Difference in Recorded Investment	[2]			$ (5)		$ (3)		$ (5)
[1]	Excludes loans that were fully paid off or fully charged-off by period end. The pre-modification balance represents the balance outstanding prior to modification. The post-modification balance represents the outstanding balance at period end.
[2]	Chapter 7 bankruptcy loans where the debt has been legally discharged through the bankruptcy court and not reaffirmed.

Loans and Loans Held for Sale51

Loans and Loans Held for Sale - Summary of Nonperforming Assets of Defaulted TDRs (Detail) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016USD ($)contract	Sep. 30, 2015USD ($)contract	Sep. 30, 2016USD ($)contract	Sep. 30, 2015USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	4
Recorded Investment | $	$ 0	$ 0	$ 0	$ 307
Commercial and Industrial
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	0
Recorded Investment | $	$ 0	$ 0	$ 0	$ 0
Commercial Real Estate
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	0
Recorded Investment | $	$ 0	$ 0	$ 0	$ 0
Commercial Construction
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	0
Recorded Investment | $	$ 0	$ 0	$ 0	$ 0
Residential Real Estate
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	1
Recorded Investment | $	$ 0	$ 0	$ 0	$ 183
Home Equity
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	3
Recorded Investment | $	$ 0	$ 0	$ 0	$ 124
Installment and Other Consumer
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	0
Recorded Investment | $	$ 0	$ 0	$ 0	$ 0
Consumer Construction
Financing Receivable, Modifications [Line Items]
Number of Defaults | contract	0	0	0	0
Recorded Investment | $	$ 0	$ 0	$ 0	$ 0

Loans and Loans Held for Sale52

Loans and Loans Held for Sale - Summary of Nonperforming Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Nonperforming Assets
Nonaccrual loans	$ 25,398	$ 27,723
Nonaccrual TDRs	15,095	7,659
Total nonaccrual loans	40,493	35,382
OREO	512	354
Total Nonperforming Assets	$ 41,005	$ 35,736

Allowance for Loan Losses - Age

Allowance for Loan Losses - Age Analysis of Past Due Loans Segregated by Class of Loans (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	$ 5,372,840	$ 5,002,925
Total nonaccrual loans	40,493	35,382
Total past due	57,088	60,008
Total Loans	5,429,928	5,062,933
Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	1,327,898	1,244,802
Total nonaccrual loans	11,890	9,279
Total past due	16,399	12,028
Total Loans	1,344,297	1,256,830
Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	2,413,004	2,145,655
Total nonaccrual loans	7,551	8,719
Total past due	14,160	20,948
Total Loans	2,427,164	2,166,603
Commercial Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	394,812	401,084
Total nonaccrual loans	6,653	8,753
Total past due	7,312	12,360
Total Loans	402,124	413,444
Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	679,237	631,085
Total nonaccrual loans	11,400	5,629
Total past due	13,337	8,287
Total Loans	692,574	639,372
Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	478,389	465,055
Total nonaccrual loans	2,955	2,902
Total past due	5,546	5,790
Total Loans	483,935	470,845
Installment and Other Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	61,954	73,486
Total nonaccrual loans	44	100
Total past due	334	453
Total Loans	62,288	73,939
Consumer Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	5,852	6,579
Total nonaccrual loans	0	0
Total past due	0	0
Total Loans	5,852	6,579
Loans Held for Sale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Loans, Current	11,694	35,179
Total nonaccrual loans	0	0
Total past due	0	142
Total Loans	11,694	35,321
30 to 59 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	10,389	22,001
30 to 59 Days Past Due | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3,536	2,453
30 to 59 Days Past Due | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3,286	11,602
30 to 59 Days Past Due | Commercial Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	456	3,517
30 to 59 Days Past Due | Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	585	1,728
30 to 59 Days Past Due | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	2,321	2,365
30 to 59 Days Past Due | Installment and Other Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	205	242
30 to 59 Days Past Due | Consumer Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
30 to 59 Days Past Due | Loans Held for Sale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	94
60 to 89 Days Past Due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	6,206	2,625
60 to 89 Days Past Due | Commercial and Industrial
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	973	296
60 to 89 Days Past Due | Commercial Real Estate
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	3,323	627
60 to 89 Days Past Due | Commercial Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	203	90
60 to 89 Days Past Due | Residential Mortgage
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	1,352	930
60 to 89 Days Past Due | Home Equity
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	270	523
60 to 89 Days Past Due | Installment and Other Consumer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	85	111
60 to 89 Days Past Due | Consumer Construction
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	0	0
60 to 89 Days Past Due | Loans Held for Sale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Total past due	$ 0	$ 48

Allowance for Loan Losses - Rec

Allowance for Loan Losses - Recorded Investment in Commercial Loan Classes by Internally Assigned Risk Ratings (Detail) - Commercial - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 4,173,585	$ 3,836,877
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 3,975,265	$ 3,653,344
Total percentage of recorded investment in commercial loan	95.20%	95.20%
Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 81,464	$ 83,680
Total percentage of recorded investment in commercial loan	2.00%	2.20%
Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 116,856	$ 99,853
Total percentage of recorded investment in commercial loan	2.80%	2.60%
Commercial and Industrial
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 1,344,297	$ 1,256,830
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Commercial and Industrial | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 1,253,411	$ 1,182,685
Total percentage of recorded investment in commercial loan	93.20%	94.10%
Commercial and Industrial | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 37,079	$ 43,896
Total percentage of recorded investment in commercial loan	2.80%	3.50%
Commercial and Industrial | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 53,807	$ 30,249
Total percentage of recorded investment in commercial loan	4.00%	2.40%
Commercial Real Estate
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 2,427,164	$ 2,166,603
Total percentage of recorded investment in commercial loan	100.00%	100.00%
Commercial Real Estate | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 2,346,848	$ 2,094,851
Total percentage of recorded investment in commercial loan	96.70%	96.70%
Commercial Real Estate | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 30,050	$ 19,938
Total percentage of recorded investment in commercial loan	1.20%	0.90%
Commercial Real Estate | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 50,266	$ 51,814
Total percentage of recorded investment in commercial loan	2.10%	2.40%
Commercial Construction
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 402,124	$ 413,444
Total percentage of recorded investment in commercial loan	99.99%	100.00%
Commercial Construction | Pass
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 375,006	$ 375,808
Total percentage of recorded investment in commercial loan	93.20%	90.90%
Commercial Construction | Special Mention
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 14,335	$ 19,846
Total percentage of recorded investment in commercial loan	3.60%	4.80%
Commercial Construction | Substandard
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 12,783	$ 17,790
Total percentage of recorded investment in commercial loan	3.20%	4.30%

Allowance for Loan Losses - Add

Allowance for Loan Losses - Additional Information (Detail) - USD ($)	9 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Loans considered nonperforming (in days)	90 days
Evaluation for impairment of substandard and nonaccrual commercial loans	$ 500,000
Impaired fiinancing receivables	38,059,000	$ 45,650,000
Integrity Bancshares, Inc.
Financing Receivable, Impaired [Line Items]
Acquired loans that experienced credit deterioration since acquisition	$ 14,400,000

Allowance for Loan Losses - R56

Allowance for Loan Losses - Recorded Investment in Consumer Loan Classes by Performing and Nonperforming Status (Detail) - Consumer - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 1,244,649	$ 1,190,735
Percentage of Total	100.00%	100.00%
Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 1,230,250	$ 1,182,104
Percentage of Total	98.80%	99.30%
Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 14,399	$ 8,631
Percentage of Total	1.20%	0.70%
Residential Mortgage
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 692,574	$ 639,372
Percentage of Total	100.00%	100.00%
Residential Mortgage | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 681,174	$ 633,743
Percentage of Total	98.40%	99.10%
Residential Mortgage | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 11,400	$ 5,629
Percentage of Total	1.60%	0.90%
Home Equity
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 483,935	$ 470,845
Percentage of Total	100.00%	100.00%
Home Equity | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 480,980	$ 467,943
Percentage of Total	99.40%	99.40%
Home Equity | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 2,955	$ 2,902
Percentage of Total	0.60%	0.60%
Installment and Other Consumer
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 62,288	$ 73,939
Percentage of Total	100.00%	100.00%
Installment and Other Consumer | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 62,244	$ 73,839
Percentage of Total	99.90%	99.80%
Installment and Other Consumer | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 44	$ 100
Percentage of Total	0.10%	0.20%
Consumer Construction
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 5,852	$ 6,579
Percentage of Total	100.00%	100.00%
Consumer Construction | Performing Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 5,852	$ 6,579
Percentage of Total	100.00%	100.00%
Consumer Construction | Nonperforming Financing Receivable
Financing Receivable, Recorded Investment [Line Items]
Loans and leases receivables, recorded investment	$ 0	$ 0
Percentage of Total	0.00%	0.00%

Allowance for Loan Losses - Inv

Allowance for Loan Losses - Investments in Loans Considered to be Impaired and Related Information on Impaired Loans (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Financing Receivable, Impaired [Line Items]
Without a related allowance recorded, Recorded Investment	$ 35,597		$ 35,597		$ 45,032
Without a related allowance, Unpaid Principal Balance	41,565		41,565		50,286
Without a related allowance recorded, Related Allowance	0		0		0
With a related allowance recorded, Recorded Investment	2,462		2,462		618
With a related allowance recorded, Unpaid Principal Balance	2,462		2,462		1,468
Impaired Financing Receivable, Recorded Investment	38,059		38,059		45,650
Impaired Financing Receivable, Unpaid Principal Balance, Total	44,027		44,027		51,754
Impaired Financing Receivable, Related Allowance	2,235		2,235		37
Without a related allowance recorded, Average Recorded Investment	34,665	$ 41,140	35,365	$ 40,631
Without a related allowance recorded, Interest Income Recognized	298	555	806	1,342
With a related allowance recorded, Average Recorded Investment	2,467	2,098	2,523	2,103
With a related allowance recorded, Interest Income Recognized	37	9	102	47
Impaired Financing Receivable, Average Recorded Investment, Total	37,132	43,238	37,888	42,734
Impaired Financing Receivable, Interest Income Recognized, Total	335	564	908	1,389
Commercial and Industrial
Financing Receivable, Impaired [Line Items]
Without a related allowance recorded, Recorded Investment	8,261		8,261		14,417
Without a related allowance, Unpaid Principal Balance	9,730		9,730		15,220
Without a related allowance recorded, Related Allowance	0		0		0
With a related allowance recorded, Recorded Investment	2,433		2,433		0
With a related allowance recorded, Unpaid Principal Balance	2,433		2,433		0
Impaired Financing Receivable, Recorded Investment	10,694		10,694		14,417
Impaired Financing Receivable, Unpaid Principal Balance, Total	12,163		12,163		15,220
Impaired Financing Receivable, Related Allowance	2,206		2,206		0
Without a related allowance recorded, Average Recorded Investment	7,326	8,993	7,447	9,742
Without a related allowance recorded, Interest Income Recognized	52	44	156	131
With a related allowance recorded, Average Recorded Investment	2,437	1,977	2,492	1,980
With a related allowance recorded, Interest Income Recognized	37	7	100	42
Impaired Financing Receivable, Average Recorded Investment, Total	9,763	10,970	9,939	11,722
Impaired Financing Receivable, Interest Income Recognized, Total	89	51	256	173
Commercial Real Estate
Financing Receivable, Impaired [Line Items]
Without a related allowance recorded, Recorded Investment	7,589		7,589		12,661
Without a related allowance, Unpaid Principal Balance	7,818		7,818		13,157
Without a related allowance recorded, Related Allowance	0		0		0
With a related allowance recorded, Recorded Investment	0		0		0
With a related allowance recorded, Unpaid Principal Balance	0		0		0
Impaired Financing Receivable, Recorded Investment	7,589		7,589		12,661
Impaired Financing Receivable, Unpaid Principal Balance, Total	7,818		7,818		13,157
Impaired Financing Receivable, Related Allowance	0		0		0
Without a related allowance recorded, Average Recorded Investment	7,582	14,101	7,551	14,994
Without a related allowance recorded, Interest Income Recognized	38	352	106	731
With a related allowance recorded, Average Recorded Investment	0	0	0	0
With a related allowance recorded, Interest Income Recognized	0	0	0	0
Impaired Financing Receivable, Average Recorded Investment, Total	7,582	14,101	7,551	14,994
Impaired Financing Receivable, Interest Income Recognized, Total	38	352	106	731
Commercial Construction
Financing Receivable, Impaired [Line Items]
Without a related allowance recorded, Recorded Investment	7,987		7,987		10,998
Without a related allowance, Unpaid Principal Balance	11,547		11,547		14,200
Without a related allowance recorded, Related Allowance	0		0		0
With a related allowance recorded, Recorded Investment	0		0		500
With a related allowance recorded, Unpaid Principal Balance	0		0		1,350
Impaired Financing Receivable, Recorded Investment	7,987		7,987		11,498
Impaired Financing Receivable, Unpaid Principal Balance, Total	11,547		11,547		15,550
Impaired Financing Receivable, Related Allowance	0		0		3
Without a related allowance recorded, Average Recorded Investment	8,039	11,034	8,498	8,920
Without a related allowance recorded, Interest Income Recognized	49	67	143	200
With a related allowance recorded, Average Recorded Investment	0	0		0
With a related allowance recorded, Interest Income Recognized	0	0		0
Impaired Financing Receivable, Average Recorded Investment, Total	8,039	11,034	8,498	8,920
Impaired Financing Receivable, Interest Income Recognized, Total	49	67	143	200
Consumer Real Estate
Financing Receivable, Impaired [Line Items]
Without a related allowance recorded, Recorded Investment	11,731		11,731		6,845
Without a related allowance, Unpaid Principal Balance	12,434		12,434		7,521
Without a related allowance recorded, Related Allowance	0		0		0
With a related allowance recorded, Recorded Investment	27		27		116
With a related allowance recorded, Unpaid Principal Balance	27		27		116
Impaired Financing Receivable, Recorded Investment	11,758		11,758		6,961
Impaired Financing Receivable, Unpaid Principal Balance, Total	12,461		12,461		7,637
Impaired Financing Receivable, Related Allowance	27		27		32
Without a related allowance recorded, Average Recorded Investment	11,686	6,829	11,831	6,856
Without a related allowance recorded, Interest Income Recognized	159	92	400	279
With a related allowance recorded, Average Recorded Investment	28	119	29	121
With a related allowance recorded, Interest Income Recognized	0	2	2	5
Impaired Financing Receivable, Average Recorded Investment, Total	11,714	6,948	11,860	6,977
Impaired Financing Receivable, Interest Income Recognized, Total	159	94	402	284
Other Consumer
Financing Receivable, Impaired [Line Items]
Without a related allowance recorded, Recorded Investment	29		29		111
Without a related allowance, Unpaid Principal Balance	36		36		188
Without a related allowance recorded, Related Allowance	0		0		0
With a related allowance recorded, Recorded Investment	2		2		2
With a related allowance recorded, Unpaid Principal Balance	2		2		2
Impaired Financing Receivable, Recorded Investment	31		31		113
Impaired Financing Receivable, Unpaid Principal Balance, Total	38		38		190
Impaired Financing Receivable, Related Allowance	2		2		$ 2
Without a related allowance recorded, Average Recorded Investment	32	183	38	119
Without a related allowance recorded, Interest Income Recognized	0	0	1	1
With a related allowance recorded, Average Recorded Investment	2	2	2	2
With a related allowance recorded, Interest Income Recognized	0	0	0	0
Impaired Financing Receivable, Average Recorded Investment, Total	34	185	40	121
Impaired Financing Receivable, Interest Income Recognized, Total	$ 0	$ 0	$ 1	$ 1

Allowance for Loan Losses - Sum

Allowance for Loan Losses - Summary of Allowance for Loan Losses (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	$ 52,213	$ 48,814	$ 48,147	$ 47,911
Charge-offs	(1,500)	(5,641)	(8,623)	(8,847)
Recoveries	564	3,528	1,890	4,370
Net (Charge-offs)/ Recoveries	(936)	(2,113)	(6,733)	(4,477)
Provision for loan losses	2,516	3,206	12,379	6,473
Balance at End of Period	53,793	49,907	53,793	49,907
Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	14,771	13,308	10,853	13,668
Charge-offs	(414)	(1,121)	(3,244)	(2,819)
Recoveries	169	272	589	475
Net (Charge-offs)/ Recoveries	(245)	(849)	(2,655)	(2,344)
Provision for loan losses	(2,232)	12	4,096	1,147
Balance at End of Period	12,294	12,471	12,294	12,471
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	15,978	19,018	15,043	20,164
Charge-offs	(93)	(2,361)	(1,808)	(2,738)
Recoveries	264	2,896	662	3,072
Net (Charge-offs)/ Recoveries	171	535	(1,146)	334
Provision for loan losses	4,244	(2,575)	6,496	(3,520)
Balance at End of Period	20,393	16,978	20,393	16,978
Commercial Construction
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	11,701	7,671	12,625	6,093
Charge-offs	(163)	(1,247)	(1,108)	(1,247)
Recoveries	17	129	20	132
Net (Charge-offs)/ Recoveries	(146)	(1,118)	(1,088)	(1,115)
Provision for loan losses	1,356	4,983	1,374	6,558
Balance at End of Period	12,911	11,536	12,911	11,536
Consumer Real Estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	8,418	7,027	8,400	6,333
Charge-offs	(369)	(445)	(891)	(997)
Recoveries	44	132	342	379
Net (Charge-offs)/ Recoveries	(325)	(313)	(549)	(618)
Provision for loan losses	(1,760)	302	(1,518)	1,301
Balance at End of Period	6,333	7,016	6,333	7,016
Other Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Balance at beginning of period	1,345	1,790	1,226	1,653
Charge-offs	(461)	(467)	(1,572)	(1,046)
Recoveries	70	99	277	312
Net (Charge-offs)/ Recoveries	(391)	(368)	(1,295)	(734)
Provision for loan losses	908	484	1,931	987
Balance at End of Period	$ 1,862	$ 1,906	$ 1,862	$ 1,906

Allowance for Loan Losses - S59

Allowance for Loan Losses - Summary of Allowance for Loan Losses and Recorded Investments (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Jun. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Dec. 31, 2014
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	$ 2,235		$ 37
Allowance for Loan Losses, Collectively Evaluated for Impairment	51,558		48,110
Total Allowance for Loan Losses	53,793	$ 52,213	48,147	$ 49,907	$ 48,814	$ 47,911
Portfolio Loans, Individually Evaluated for Impairment	38,059		45,650
Portfolio Loans, Collectively Evaluated for Impairment	5,380,175		4,981,962
Total Portfolio Loans	5,418,234		5,027,612
Commercial and Industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	2,206		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	10,088		10,853
Total Allowance for Loan Losses	12,294	14,771	10,853	12,471	13,308	13,668
Portfolio Loans, Individually Evaluated for Impairment	10,694		14,417
Portfolio Loans, Collectively Evaluated for Impairment	1,333,603		1,242,413
Total Portfolio Loans	1,344,297		1,256,830
Commercial Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		0
Allowance for Loan Losses, Collectively Evaluated for Impairment	20,393		15,043
Total Allowance for Loan Losses	20,393	15,978	15,043	16,978	19,018	20,164
Portfolio Loans, Individually Evaluated for Impairment	7,589		12,661
Portfolio Loans, Collectively Evaluated for Impairment	2,419,575		2,153,942
Total Portfolio Loans	2,427,164		2,166,603
Commercial Construction
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	0		3
Allowance for Loan Losses, Collectively Evaluated for Impairment	12,911		12,622
Total Allowance for Loan Losses	12,911	11,701	12,625	11,536	7,671	6,093
Portfolio Loans, Individually Evaluated for Impairment	7,987		11,498
Portfolio Loans, Collectively Evaluated for Impairment	394,137		401,946
Total Portfolio Loans	402,124		413,444
Consumer Real Estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	27		32
Allowance for Loan Losses, Collectively Evaluated for Impairment	6,306		8,368
Total Allowance for Loan Losses	6,333	8,418	8,400	7,016	7,027	6,333
Portfolio Loans, Individually Evaluated for Impairment	11,758		6,961
Portfolio Loans, Collectively Evaluated for Impairment	1,170,603		1,109,835
Total Portfolio Loans	1,182,361		1,116,796
Other Consumer
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for Loan Losses, Individually Evaluated for Impairment	2		2
Allowance for Loan Losses, Collectively Evaluated for Impairment	1,860		1,224
Total Allowance for Loan Losses	1,862	$ 1,345	1,226	$ 1,906	$ 1,790	$ 1,653
Portfolio Loans, Individually Evaluated for Impairment	31		113
Portfolio Loans, Collectively Evaluated for Impairment	62,257		73,826
Total Portfolio Loans	$ 62,288		$ 73,939

Derivative Instruments and He60

Derivative Instruments and Hedging Activities - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Period for commitments	60 days

Derivative Instruments and He61

Derivative Instruments and Hedging Activities - Value of Derivative Assets and Derivative Liabilities (Detail) - Not Designated as Hedging Instruments - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Other Assets
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)		$ 15,255	$ 11,295
Collateral posted, Derivatives	[1]	0	0
Other Assets | Interest Rate Swaps
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)		15,255	11,295
Notional amount, Derivatives (included in Other Assets)		264,655	245,595
Collateral posted, Derivatives		0	0
Other Assets | Interest Rate Lock Commitments
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)		739	261
Notional amount, Derivatives (included in Other Assets)		21,699	9,894
Other Assets | Forward Sale Contracts
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Assets)		0	0
Notional amount, Derivatives (included in Other Assets)		0	0
Other Liabilities
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)		15,202	11,276
Collateral posted, Derivatives	[1]	14,542	12,573
Other Liabilities | Interest Rate Swaps
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)		15,202	11,276
Notional amount, Derivatives (included in Other Liabilities)		264,655	245,595
Collateral posted, Derivatives		14,542	12,753
Other Liabilities | Interest Rate Lock Commitments
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)		0	0
Notional amount, Derivatives (included in Other Liabilities)		0	0
Other Liabilities | Forward Sale Contracts
Derivatives not Designated as Hedging Instruments
Fair value, Derivatives (included in Other Liabilities)		98	5
Notional amount, Derivatives (included in Other Liabilities)		$ 16,892	$ 9,800
[1]	Amounts represent posted collateral.

Derivative Instruments and He62

Derivative Instruments and Hedging Activities - Schedule of Gross Amounts of Derivative Assets and Derivative Liabilities (Detail) - Not Designated as Hedging Instruments - USD ($) $ in Thousands		Sep. 30, 2016	Dec. 31, 2015
Other Assets
Derivative Asset [Abstract]
Gross amounts recognized		$ 15,255	$ 11,295
Gross amounts offset		0	0
Net amounts presented in the Consolidated Balance Sheets		15,255	11,295
Net Amount		15,255	11,295
Derivative Liability [Abstract]
Gross amounts not offset	[1]	0	0
Other Liabilities
Derivative Liability [Abstract]
Gross amounts recognized		15,202	11,276
Gross amounts offset		0	0
Net amounts presented in the Consolidated Balance Sheets		15,202	11,276
Gross amounts not offset	[1]	(14,542)	(12,573)
Net Amount		$ 660	$ (1,297)
[1]	Amounts represent posted collateral.

Derivative Instruments and He63

Derivative Instruments and Hedging Activities - Amount of Gain or Loss Recognized in Income on Derivatives (Detail) - Not Designated as Hedging Instruments - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivatives Gain	$ 116	$ 94	$ 419	$ 290
Interest Rate Swap Contracts - Commercial Loans
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivatives Gain	(87)	29	34	20
Interest Rate Lock Commitments - Mortgage Loans
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivatives Gain	97	208	478	339
Forward Sale Contracts - Mortgage Loans
Derivative Instruments, Gain (Loss) [Line Items]
Total Derivatives Gain	$ 106	$ (143)	$ (93)	$ (69)

Borrowings - Additional Informa

Borrowings - Additional Information (Detail) - USD ($)	Jun. 18, 2015	Mar. 05, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015	Mar. 04, 2015
Long Term And Short Term Debt [Line Items]
Total long-term debt outstanding at a fixed rate			$ 12,100,000
Total long-term debt outstanding at a variable rate			3,100,000
Capital lease			100,000
Repayment of junior subordinated debt			0	$ 13,500,000
Federal Home Loan Bank Advance
Long Term And Short Term Debt [Line Items]
Total borrowings			580,200,000		$ 473,000,000
Short-term borrowings			565,000,000
Long-term borrowings			15,200,000
Maximum borrowing capacity			2,200,000,000
Remaining borrowing capacity			1,400,000,000
Borrowing capacity utilized			802,100,000
Letter of credit to collateralize public funds			221,900,000
Junior Subordinated Debt
Long Term And Short Term Debt [Line Items]
Repayment of junior subordinated debt	$ 5,000,000	$ 8,500,000
Integrity Bancshares, Inc. | Junior Subordinated Debt
Long Term And Short Term Debt [Line Items]
Debt assumed in acquisition						$ 13,500,000
Mortgage Backed Securities
Long Term And Short Term Debt [Line Items]
Mortgage backed securities pledged as collateral			$ 47,400,000		$ 67,000,000

Borrowings - Summary of Informa

Borrowings - Summary of Information Pertaining to Borrowings (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Long Term And Short Term Debt [Line Items]
Short-term borrowings	$ 605,949	$ 418,086
Long-term borrowings	60,922	162,662
Total Borrowings	$ 666,871	$ 580,748
Short-term borrowings, Weighted Average Rate	0.56%	0.44%
Long-term borrowings, Weighted Average Rate	3.06%	1.39%
Total Borrowings, Weighted Average Rate	0.79%	0.71%
Securities Sold under Repurchase Agreements
Long Term And Short Term Debt [Line Items]
Short-term borrowings	$ 40,949	$ 62,086
Short-term borrowings, Weighted Average Rate	0.01%	0.01%
Short-Term Borrowings
Long Term And Short Term Debt [Line Items]
Short-term borrowings	$ 565,000	$ 356,000
Short-term borrowings, Weighted Average Rate	0.60%	0.52%
Other Long-Term Borrowings
Long Term And Short Term Debt [Line Items]
Long-term borrowings	$ 15,303	$ 117,043
Long-term borrowings, Weighted Average Rate	2.91%	0.81%
Junior Subordinated Debt Securities
Long Term And Short Term Debt [Line Items]
Long-term borrowings	$ 45,619	$ 45,619
Long-term borrowings, Weighted Average Rate	3.11%	2.89%

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Detail) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Allowance for unfunded commitments	$ 2.6	$ 2.5

Commitments and Contingencies67

Commitments and Contingencies - Commitments and Letters of Credit (Detail) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2016	Dec. 31, 2015
Other Commitments [Line Items]
Commitments and letters of credit	$ 1,626,345	$ 1,717,530
Commitments to Extend Credit
Other Commitments [Line Items]
Commitments and letters of credit	1,546,164	1,619,854
Standby Letters of Credit
Other Commitments [Line Items]
Commitments and letters of credit	$ 80,181	$ 97,676

Other Comprehensive Income (Det

Other Comprehensive Income (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Pre-Tax Amount
Change in net unrealized gains/(losses) on securities available-for-sale		$ (1,921)	$ 5,177	$ 11,748	$ 4,288
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	0	0	0	34
Adjustment to funded status of employee benefit plans		544	647	4,889	1,839
Other Comprehensive Income/(Loss)		(1,377)	5,824	16,637	6,161
Tax (Expense) Benefit
Change in net unrealized gains/(losses) on securities available-for-sale		672	(1,812)	(4,112)	(1,501)
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	0	0	0	(12)
Adjustment to funded status of employee benefit plans		(190)	(227)	(1,711)	(551)
Other Comprehensive (Loss)/Income		482	(2,039)	(5,823)	(2,064)
Net of Tax Amount
Change in net unrealized gains/(losses) on securities available-for-sale		(1,249)	3,365	7,636	2,787
Reclassification adjustment for net (gains)/losses on securities available-for-sale included in net income	[1]	0	0	0	22
Adjustment to funded status of employee benefit plans		354	420	3,178	1,288
Other Comprehensive Income/(Loss)		$ (895)	$ 3,785	$ 10,814	$ 4,097
[1]	Reclassification adjustments are comprised of realized security gains or losses. The realized gains or losses have been reclassified out of accumulated other comprehensive income and have affected certain lines in the consolidated statement of comprehensive income as follows; the pre-tax amount is included in securities gains/losses-net, the tax expense amount is included in the provision for income taxes and the net of tax amount is included in net income.

Employee Benefits - Additional

Employee Benefits - Additional Information (Detail) - USD ($) $ in Millions	Jan. 01, 2015	Mar. 31, 2016	Dec. 31, 2015
Compensation and Retirement Disclosure [Abstract]
Pension plan curtailment gain		$ 1
Period of unrecognized benefits associated with prior year plan amendments that would have been amortized into income		7 years
Number of consecutive years of employee's compensation			5 years
Number of total years of employee's compensation			10 years
Expected long-term rate of return on plan assets			7.50%
Lump sum death benefit to unmarried beneficiary as percent of accrued benefit payable (percent)	80.00%

Employee Benefits - Components

Employee Benefits - Components of Net Periodic Pension Cost and Other Changes in Plan Assets and Benefit (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Components of Net Periodic Pension Cost
Service cost—benefits earned during the period	$ (6)	$ 606	$ 469	$ 1,951
Interest cost on projected benefit obligation	1,099	1,120	3,200	3,319
Expected return on plan assets	(1,444)	(1,772)	(4,337)	(5,385)
Amortization of prior service credit	29	(34)	(41)	(104)
Recognized net actuarial loss	638	586	1,708	1,521
Net Periodic Pension Expense	$ 316	$ 506	$ 999	$ 1,302

Segments - Additional Informati

Segments - Additional Information (Detail)	9 Months Ended
	Sep. 30, 2016segment
Segment Reporting [Abstract]
Number of reportable segments	3
Number of operating segments	3

Segments - Total Assets by Repo

Segments - Total Assets by Reportable Operating Segment (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	$ 6,718,205	$ 6,318,354
Operating Segments | Community Banking
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	6,706,383	6,305,046
Operating Segments | Insurance
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	8,050	9,619
Operating Segments | Wealth Management
Segment Reporting, Asset Reconciling Item [Line Items]
Total Assets	$ 3,772	$ 3,689

Segments - Financial Informatio

Segments - Financial Information of Segments (Detail) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	$ 57,808	$ 53,669	$ 168,678	$ 150,195
Interest expense	6,353	4,073	17,877	11,529
NET INTEREST INCOME	51,455	49,596	150,801	138,666
Provision for loan losses	2,516	3,206	12,379	6,473
Noninterest income	13,448	12,481	41,713	37,948
Noninterest expense	32,780	32,138	102,641	98,014
Depreciation expense	1,284	1,211	3,723	3,540
Amortization of intangible assets	375	480	1,243	1,345
Provision for income taxes	7,367	6,407	18,795	17,584
Net Income	20,581	18,635	53,733	49,658
Operating Segments | Community Banking
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	57,804	53,625	168,661	150,108
Interest expense	6,433	4,200	18,085	12,144
NET INTEREST INCOME	51,371	49,425	150,576	137,964
Provision for loan losses	2,516	3,206	12,379	6,473
Noninterest income	9,548	8,651	28,468	25,056
Noninterest expense	28,889	28,941	90,499	87,542
Depreciation expense	1,269	1,192	3,678	3,482
Amortization of intangible assets	359	460	1,189	1,283
Provision for income taxes	7,347	6,139	18,364	16,534
Net Income	20,539	18,138	52,935	47,706
Operating Segments | Insurance
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	1	1	2	2
NET INTEREST INCOME	1	1	2	2
Noninterest income	1,119	1,197	3,836	4,079
Noninterest expense	1,097	1,098	3,455	3,288
Depreciation expense	11	13	33	39
Amortization of intangible assets	12	13	37	38
Provision for income taxes	(1)	26	110	250
Net Income	1	48	203	466
Operating Segments | Wealth Management
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	98	108	343	406
NET INTEREST INCOME	98	108	343	406
Noninterest income	2,563	2,806	7,936	8,639
Noninterest expense	2,591	2,210	7,334	6,716
Depreciation expense	4	6	12	19
Amortization of intangible assets	4	7	17	24
Provision for income taxes	21	242	321	800
Net Income	41	449	595	1,486
Eliminations
Segment Reporting, Asset Reconciling Item [Line Items]
Interest income	(95)	(65)	(328)	(321)
Interest expense	(80)	(127)	(208)	(615)
NET INTEREST INCOME	(15)	62	(120)	294
Noninterest income	218	(173)	1,473	174
Noninterest expense	$ 203	$ (111)	$ 1,353	$ 468

Qualified Affordable Housing 74

Qualified Affordable Housing Projects (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Investments in Affordable Housing Projects [Abstract]
Investment in qualified affordable housing projects	$ 12,600,000		$ 12,600,000		$ 15,000,000
Open commitments	0		0		$ 0
Amortization expense included in noninterest expense	800,000	$ 900,000	2,500,000	$ 2,800,000
Tax credits	$ 900,000	$ 1,000,000	$ 2,700,000	$ 3,000,000