Northwest Bancshares (NWBI) 10-K 1 Mar 17 2016 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Feb. 15, 2017	Jun. 30, 2016
Document and Entity Information
Entity Registrant Name	Northwest Bancshares, Inc.
Entity Central Index Key	1,471,265
Current Fiscal Year End Date	--12-31
Entity Filer Category	Large Accelerated Filer
Document Type	10-K
Document Period End Date	Dec. 31, 2016
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		101,824,211
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 1,520

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 119,403	$ 92,263
Interest-earning deposits in other financial institutions	266,902	74,510
Federal funds sold and other short-term investments	3,562	635
Marketable securities available-for-sale (amortized cost of $825,552 and $868,956)	826,200	874,405
Marketable securities held-to-maturity (fair value of $20,426 and $32,552)	19,978	31,689
Loans receivable, net of allowance for loan losses of $60,939 and $62,672	7,496,408	7,159,449
Disposal Group, Including Discontinued Operation, Assets	152,528	0
Accrued interest receivable	21,699	21,072
Real estate owned, net	4,889	8,725
Federal Home Loan Bank stock, at cost	7,390	40,903
Premises and equipment, net	161,185	154,351
Bank owned life insurance	171,449	168,509
Goodwill	307,420	261,736
Other intangible assets	32,433	8,982
Other assets	32,194	54,670
Total assets	9,623,640	8,951,899
Liabilities:
Deposits	7,882,321	6,612,581
Disposal Group, Including Discontinued Operation, Liabilities	215,657	0
Borrowed funds	142,899	975,007
Advances by borrowers for taxes and insurance	36,879	33,735
Accrued interest payable	635	1,993
Other liabilities	63,373	54,207
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	111,213	111,213
Total liabilities	8,452,977	7,788,736
Shareholders’ equity:
Preferred stock, $0.01 par value: 50,000,000 authorized, no shares issued	0	0
Common stock, $0.01 par value: 500,000,000 shares authorized, 101,699,406 and 101,871,737 shares issued, respectively	1,017	1,019
Paid-in capital	718,834	717,603
Retained earnings	478,803	489,292
Unallocated common stock of employee stock ownership plan	0	(20,216)
Accumulated other comprehensive loss	(27,991)	(24,535)
Total shareholders' equity	1,170,663	1,163,163
Total liabilities and shareholders’ equity	$ 9,623,640	$ 8,951,899

CONSOLIDATED STATEMENTS OF FIN3

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Marketable securities available-for-sale, amortized cost	$ 825,552	$ 868,956
Marketable securities held-to-maturity, fair value	20,426	32,552
Allowance for loan losses	$ 60,939	$ 62,672
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	50,000,000	50,000,000
Preferred stock, shares issued	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	500,000,000	500,000,000
Common stock, shares issued	101,699,406	101,871,737

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Interest income:
Loans receivable	$ 329,039	$ 298,665	$ 282,050
Mortgage-backed securities	8,540	8,823	10,320
Taxable investment securities	3,409	4,520	4,130
Tax-free investment securities	2,732	4,313	6,281
FHLB dividends	1,371	2,828	1,809
Interest-earning deposits	543	431	837
Total interest income	345,634	319,580	305,427
Interest expense:
Deposits	23,465	24,055	25,322
Borrowed funds	14,834	32,272	31,265
Total interest expense	38,299	56,327	56,587
Net interest income	307,335	263,253	248,840
Provision for loan losses	13,542	9,712	20,314
Net interest income after provision for loan losses	293,793	253,541	228,526
Noninterest income:
Gain on sale of investments, net	625	1,037	4,930
Service charges and fees	44,113	38,362	36,383
Trust and other financial services income	14,103	12,342	12,369
Insurance commission income	10,522	9,526	8,760
Loss on real estate owned, net	(39)	(1,989)	(967)
Income from bank owned life insurance	5,361	4,338	4,191
Mortgage banking income	4,894	933	1,022
Other operating income	5,781	4,287	4,078
Total noninterest income	85,360	68,836	70,766
Noninterest expense:
Compensation and employee benefits	140,927	119,818	115,967
Premises and occupancy costs	26,134	24,641	23,455
Office operations	14,898	12,337	11,710
Collections expense	2,431	3,247	3,011
Processing expenses	34,859	30,780	26,671
Professional services	7,865	6,906	7,661
Amortization of other intangible assets	4,259	1,688	1,323
Marketing expenses	8,852	8,499	8,213
Real estate owned expense	1,004	2,070	2,140
Federal deposit insurance premiums	4,404	5,109	5,193
Restructuring/ acquisition expense	12,213	9,751	394
FHLB prepayment penalty	36,978	0	0
Other expenses	13,014	9,031	9,797
Total noninterest expense	307,838	233,877	215,535
Income before income taxes	71,315	88,500	83,757
Provision for income taxes:
Federal	20,313	24,010	19,656
State	1,335	3,950	2,139
Total provision for income taxes	21,648	27,960	21,795
Net income	$ 49,667	$ 60,540	$ 61,962
Basic earnings per share (in dollars per share)	$ 0.50	$ 0.64	$ 0.68
Diluted earnings per share (in dollars per share)	$ 0.49	$ 0.64	$ 0.67

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 49,667	$ 60,540	$ 61,962
Net unrealized holding gains/ (losses) on marketable securities:
Unrealized holding gains/ (losses), net of tax of $1,742, $(204) and $(5,787), respectively	(2,728)	315	9,042
Reclassification adjustment for gains included in net income, net of tax of $129, $289 and $1,501, respectively	(202)	(451)	(2,348)
Net unrealized holding gains/ (losses) on marketable securities	(2,930)	(136)	6,694
Change in fair value of interest rate swaps, net of tax of $(539), $(699) and $(618), respectively	1,001	1,299	1,146
Defined benefit plans:
Net loss, net of tax of $3,061, $1,408 and $12,650, respectively	(2,399)	(2,203)	(19,758)
Amortization of prior service costs, net of tax of $(606), $(560) and $335, respectively	872	875	(552)
Net loss on defined benefit plans	(1,527)	(1,328)	(20,310)
Other comprehensive loss	(3,456)	(165)	(12,470)
Total comprehensive income	$ 46,211	$ 60,375	$ 49,492

CONSOLIDATED STATEMENTS OF COM6

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Unrealized holding gains/(losses), tax	$ 1,742	$ (204)	$ (5,787)
Reclassification adjustment for gains included in net income, tax	129	289	1,501
Change in fair value of interest rate swaps, tax	(539)	(699)	(618)
Net loss on defined benefit plans, tax	3,061	1,408	12,650
Amortization of prior service costs included in net income, tax	$ (606)	$ (560)	$ 335

CONSOLIDATED STATEMENTS OF CHAN

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Stock	Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income/ (Loss)	Unallocated Common Stock of ESOP
Balance at beginning of the period at Dec. 31, 2013	$ 1,155,185	$ 943	$ 619,678	$ 569,547	$ (11,900)	$ (23,083)
Comprehensive income:
Net Income	61,962			61,962
Other comprehensive loss, net of tax of $234, $8,081, and $559 for the year ended December 31, 2016, 2015 and 2014, respectively	(12,470)				(12,470)
Total comprehensive income	49,492			61,962	(12,470)
Exercise of stock options	6,519	6	6,513
Share repurchases	(5,273)	(4)	(5,269)
Stock-based compensation expense including tax benefits of $332, $945, and $635 for the year ended December 31, 2016, 2015 and 2014, respectively	6,656	2	5,212			1,442
Dividends paid ($0.56, $1.62, and $0.50 per share for the year ended December 31, 2016, 2015 and 2014, respectively)	(149,932)			(149,932)
Balance at end of the period at Dec. 31, 2014	1,062,647	947	626,134	481,577	(24,370)	(21,641)
Comprehensive income:
Net Income	60,540			60,540
Other comprehensive loss, net of tax of $234, $8,081, and $559 for the year ended December 31, 2016, 2015 and 2014, respectively	(165)				(165)
Total comprehensive income	60,375			60,540	(165)
ESOP termination	90,608	70	90,538
Exercise of stock options	4,303	5	4,298
Share repurchases	(7,847)	(6)	(7,841)
Stock-based compensation expense including tax benefits of $332, $945, and $635 for the year ended December 31, 2016, 2015 and 2014, respectively	5,902	3	4,474	0		1,425
Dividends paid ($0.56, $1.62, and $0.50 per share for the year ended December 31, 2016, 2015 and 2014, respectively)	(52,825)			(52,825)
Balance at end of the period at Dec. 31, 2015	1,163,163	1,019	717,603	489,292	(24,535)	(20,216)
Comprehensive income:
Net Income	49,667			49,667
Other comprehensive loss, net of tax of $234, $8,081, and $559 for the year ended December 31, 2016, 2015 and 2014, respectively	(3,456)				(3,456)
Total comprehensive income	46,211			49,667	(3,456)
ESOP termination	0	(14)	(13,896)			13,910
Exercise of stock options	10,856	11	10,845
Share repurchases	(1,752)	(2)	(1,750)
Stock-based compensation expense including tax benefits of $332, $945, and $635 for the year ended December 31, 2016, 2015 and 2014, respectively	12,341	3	6,032			6,306
Dividends paid ($0.56, $1.62, and $0.50 per share for the year ended December 31, 2016, 2015 and 2014, respectively)	(60,156)			(60,156)
Balance at end of the period at Dec. 31, 2016	$ 1,170,663	$ 1,017	$ 718,834	$ 478,803	$ (27,991)	$ 0

CONSOLIDATED STATEMENTS OF CHA8

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Other comprehensive income, tax	$ 3,787	$ 234	$ 8,081
Stock-based compensation expense, tax benefits	$ 1,425	$ 332	$ 945
Dividends paid, per share (in dollars per share)	$ 0.60	$ 0.56	$ 1.62

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net Income	$ 49,667	$ 60,540	$ 61,962
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	13,542	9,712	20,314
Net gain on sale of assets	(4,499)	(921)	(5,236)
Net depreciation, amortization and accretion	15,424	8,958	9,868
Decrease in other assets	25,953	37,969	9,241
Increase/ (decrease) in other liabilities	4,801	(18,998)	(22,857)
Net amortization of premium on marketable securities	2,139	1,149	383
Noncash compensation expense related to stock benefit plans	10,916	5,570	5,711
Noncash impairment of real estate owned	1,481	2,923	2,318
Deferred income tax expense	2,734	6,290	8,595
FHLB prepayment penalty	24,520	0	0
Origination of loans held for sale	(252,204)	(2,504)	(1,042)
Proceeds from sale of loans held for sale	242,428	2,514	1,315
Net cash provided by operating activities	136,902	113,202	90,572
Investing activities:
Purchase of marketable securities available-for-sale	(238,673)	(59,980)	(49,996)
Proceeds from maturities and principal reductions of marketable securities held-to-maturity	11,700	72,265	17,673
Proceeds from maturities and principal reductions of marketable securities available-for-sale	278,621	280,277	162,007
Proceeds from sale of marketable securities available-for-sale	1,951	1,246	7,910
Loan originations	(2,706,358)	(2,319,800)	(1,944,677)
Proceeds from loan maturities and principal reductions	2,672,924	2,000,712	1,730,603
(Purchases)/ redemptions of Federal Home Loan Bank stock	33,513	(3,770)	10,422
Proceeds from sale of real estate owned	8,113	13,961	10,216
Sale of real estate owned for investment, net	607	608	607
Purchases of premises and equipment	(15,227)	(13,223)	(9,968)
Acquisitions, net of cash received	1,102,237	(61,108)	(2,792)
Net cash provided by/ (used in) investing activities	1,149,408	(88,812)	(67,995)
Financing activities:
Decrease in deposits, net	(157,457)	(60,236)	(36,337)
Proceeds from long-term borrowings	0	135,000	0
Repayments of long-term borrowings	(774,863)	(172,552)	(52)
Net increase/ (decrease) in short-term borrowings	(81,765)	61,281	6,516
Increase/ (decrease) in advances by borrowers for taxes and insurance	(139)	2,975	3,838
Redemption of Junior subordinated debentures	0	(8,119)	0
Share repurchases	(1,752)	(7,847)	(5,273)
Cash dividends paid on common stock	(60,156)	(52,825)	(149,932)
Proceeds from stock options exercised	10,856	4,303	6,519
Excess tax benefit from stock-based compensation	1,425	332	945
Net cash used in financing activities	(1,063,851)	(97,688)	(173,776)
Net increase/ (decrease) in cash and cash equivalents	222,459	(73,298)	(151,199)
Cash and cash equivalents at beginning of period	167,408	240,706	391,905
Net decrease in cash and cash equivalents	222,459	(73,298)	(151,199)
Cash and cash equivalents at end of period	389,867	167,408	240,706
Cash and cash equivalents:
Total cash and cash equivalents	167,408	240,706	391,905
Cash paid during the period for:
Interest on deposits and borrowings (including interest credited to deposit accounts of $22,213, $21,949 and $22,783, respectively)	39,649	55,270	56,539
Income taxes	9,710	16,719	26,042
Business acquisitions:
Fair value of assets acquired	546,247	1,160,190	2,798
Net cash (paid)/ received	1,102,237	(61,108)	(2,792)
Liabilities assumed	1,648,484	1,099,082	6
Loan foreclosures and repossessions	6,252	7,633	10,820
Sale of real estate owned financed by the Company	$ 420	$ 2,264	$ 486

CONSOLIDATED STATEMENTS OF CA10

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Cash Flows [Abstract]
Interest on deposits and borrowings, interest credited to deposit accounts	$ 22,213	$ 21,949	$ 22,783

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies (a) Nature of Operations Northwest Bancshares, Inc., a Maryland corporation headquartered in Warren, Pennsylvania, is the federal savings and loan holding company for its wholly owned subsidiary, Northwest Bank. Northwest Bank, a Pennsylvania chartered savings bank, offers personal and business deposit and loan products as well as investment management and insurance services through its 176 banking locations in Pennsylvania, New York, Ohio and Maryland. Northwest Bank, through its subsidiary Northwest Consumer Discount Company, also offers personal loan products through 49 consumer finance offices in Pennsylvania. (b) Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries after elimination of all intercompany accounts and transactions. (c) Cash and Cash Equivalents For purposes of the statement of cash flows, cash and cash equivalents include cash and amounts due from banks, interest-bearing deposits in other financial institutions, federal funds sold, and other short-term investments with original maturities of three months or less. (d) Investment Securities We classify marketable securities at the time of purchase as held-to-maturity, available-for-sale, or trading securities. Securities for which management has the intent and ability to hold until maturity are classified as held-to-maturity and are carried at cost, adjusted for amortization of premiums and accretion of discounts on a level yield basis (amortized cost). If it is management’s intent at the time of purchase to hold securities for an indefinite period of time and/or to use such securities as part of its asset/liability management strategy, the securities are classified as available-for-sale and are carried at fair value, with unrealized gains and losses reported as accumulated other comprehensive income/ (loss), a separate component of shareholders’ equity, net of tax. Securities classified as available-for-sale include securities that may be sold in response to changes in interest rates, resultant prepayment risk, or other market factors. Securities that are bought and held principally for the purpose of selling them in the near term are classified as trading and are reported at fair value, with changes in fair value included in earnings. The cost of securities sold is determined on a specific identification basis. We held no securities classified as trading at or for the years ended December 31, 2016 and 2015 . On at least a quarterly basis, we review our investments for other-than-temporary impairment (“OTTI”). An investment security is deemed impaired if the fair value of the investment is less than its amortized cost. If an investment security is determined to be impaired, we evaluate whether the decline in value is other-than-temporary. We consider whether or not we expect to receive all of the contractual cash flows from the investment security based on factors that include, but are not limited to the creditworthiness of the issuer and the historical and projected performance of the underlying collateral. Also, we may evaluate the business and financial outlook of the issuer, as well as broader economic performance indicators. We consider both our intent to sell and the likelihood that we will not have to sell the investment securities before recovery of their cost basis during our evaluation. Impairment that is deemed credit related is recognized in earnings while impairment deemed noncredit related is recorded in accumulated other comprehensive income, if we do not intend to sell nor it is not likely we will be required to sell the investment security. If we intend to sell the investment security or if it is more likely than not that we will be required to sell the investment security, the entire impairment is recorded in earnings. Federal law requires a member institution of the Federal Home Loan Bank ("FHLB") system to hold stock of its district FHLB according to a predetermined formula. This stock is recorded at cost. Quarterly, we evaluate our investment in the FHLB of Pittsburgh for impairment. We evaluate recent and long-term operating performance, liquidity, funding and capital positions, stock repurchase history, dividend history and impact of legislative and regulatory changes. Based on our most recent evaluation, we have determined that no impairment write-downs are currently required. (e) Loans Receivable Our loan portfolio segments consist of Personal Banking and Business Banking loans. Personal Banking loans include the following classes: residential mortgage loans, home equity loans and other consumer loans. Business Banking loans include the following classes: commercial real estate loans and commercial loans. All classes of originated loans are carried at their unpaid principal balance net of any deferred origination fees or costs and the allowance for loan losses. Interest income on loans is credited to income as earned. Interest earned on loans for which no payments were received during the month is accrued at month end. Accrued interest on loans more than 90 days delinquent is reversed and such loans are placed on nonaccrual status. All loans are placed on nonaccrual status when principal or interest is 90 days or more delinquent or when there is reasonable doubt that interest or principal will not be collected in accordance with the contractual terms. Interest receipts on all nonaccrual and impaired loans are recognized as interest revenue when it has been determined that all principal and interest will be collected or are applied to principal when collectability of principal is in doubt. Nonaccrual loans generally are restored to an accrual basis when principal and interest become current and a period of performance has been established in accordance with the contractual terms, typically six months . A loan is considered to be a troubled debt restructured loan ("TDR") when the restructuring constitutes a concession and the borrower is experiencing financial difficulties. TDRs may include modifications of terms of loans, receipts of assets from borrowers in partial or full satisfaction of loans, or a combination thereof. TDRs are impaired loans. A modified loan is determined to be a TDR based on the contractual terms as specified by the original loan agreement or the most recent modification. Once classified a TDR, a loan is removed from such classification under three circumstances: (1) the loan is paid off, (2) the loan is charged off, or (3) if, at the beginning of the current fiscal year, the loan has performed in accordance with the modified terms for a minimum of six consecutive months and at the time of modification the loan’s interest rate represented a then current market interest rate for a loan of similar risk. Loan delinquency is measured based on the number of days since the payment due date. Past due status is measured using the loan’s contractual maturity date. Loan fees and certain direct loan origination costs are deferred and the net deferred fee or cost is then recognized using the level-yield method over the contractual life of the loan as an adjustment to interest income. We identify certain residential mortgage loans which will be sold prior to maturity, as loans held for sale. These loans are recorded at the lower of amortized cost or fair value less estimated cost to sell. At December 31, 2016 and 2015 , there were $36.0 million and $0 residential mortgage loans classified as held for sale, respectively. Acquired loans are recorded at fair value with no carryover of the related allowance for loan losses. 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 excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable discount and is recognized into interest income over the remaining life of the loan. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable discount. The nonaccretable discount represents estimated future credit losses expected to be incurred over the life of the loan. Subsequent decreases to the expected cash flows require us to evaluate the need for an allowance for loan losses. Subsequent improvements in expected cash flows result in the reversal of a corresponding amount of the nonaccretable discount which we then reclassify as accretable discount that is recognized into interest income over the remaining life of the loan using the interest method. Charge-offs of the principal amount on acquired loans would be first applied to the nonaccretable discount portion of the fair value adjustment. Acquired loans that met the criteria for nonaccrual of interest prior to the acquisition may be considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of the expected cash flows on such loans and if we expect to fully collect the new carrying value of the loans. As such, we may no longer consider the loan to be nonaccrual or nonperforming and may accrue interest on these loans, including the impact of any accretable discount. We have determined that we can reasonably estimate future cash flows on our current portfolio of acquired loans that are past due 90 days or more and on which we are accruing interest and we expect to fully collect the carrying value of the loans. (f) Allowance for Loan Losses and Provision for Loan Losses Provisions for estimated loan losses and the amount of the allowance for loan losses are based on losses inherent in the loan portfolio that are both probable and can be reasonably estimated at the date of the financial statements. We consider a loan to be impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. In evaluating whether a loan is impaired, we consider not only the amount that we expect to collect but also the timing of collection. Generally, if a delay in payment is insignificant (e.g., less than 30 days ), a loan is not deemed to be impaired. Business Banking loans greater than or equal to $1.0 million are reviewed to determine if they should be individually evaluated for impairment. Smaller balance, homogeneous loans (e.g., primarily residential mortgage, home equity and consumer loans) are evaluated collectively for impairment. When a loan is considered to be impaired, the amount of impairment is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s market price, or fair value of the collateral, less estimated cost to sell, if the loan is collateral dependent. Impairment losses are included in the allowance for loan losses. Impaired loans are charged-off or charged down when we believe that the ultimate collectability of a loan is not likely or the collateral value no longer supports the carrying value of the loan. Interest income on non-performing loans is recognized using the cash basis method. For non-performing loans interest collected is credited to income in the period of recovery or applied to reduce principal if there is sufficient doubt about the collectability of principal. The allowance for loan losses is shown as a valuation allowance to loans. The accounting policy for the determination of the adequacy of the allowance by portfolio segment requires us to make numerous complex and subjective estimates and assumptions relating to amounts which are inherently uncertain. The allowance for loan losses is maintained to absorb losses inherent in the loan portfolio as of the balance sheet date. The methodology used to determine the allowance for loan losses is designed to provide procedural discipline in assessing the appropriateness of the allowance for loan losses. Losses are charged against and recoveries are added to the allowance for loan losses. For Business Banking loans the allowance for loan losses consists of: • An allowance for impaired loans; • An allowance for homogenous loans based on historical losses; and • An allowance for homogenous loans based on environmental factors. The allowance for impaired loans is based on individual analysis of all nonperforming loans greater than or equal to $1.0 million . The allowance is measured by the difference between the recorded value of impaired loans and their impaired value. The impaired value is either the present value of the expected future cash flows from the borrower, the market value of the loan, or the fair value of the collateral, less estimated cost to sell. The allowance for homogeneous loans based on historical factors is a rolling three -year average of actual losses incurred, adjusted for a loss realization period (the period of time from the event of loss to loss realization), applied to homogenous pools of loans categorized by similar risk characteristics, not including loans evaluated individually for impairment. The allowance for homogeneous loans based on environmental factors augments the historical loss factors for changes in: economic conditions, lending policies and procedures, the nature and volume of the loan portfolio, management, delinquency trends, loan administration, collateral values, concentrations of credit, and other external factors including legal and regulatory factors. For Personal Banking loans the allowance for loan losses consists of: • An allowance for loans 90 days or more delinquent; • An allowance for homogenous loans based on historical losses; and • An allowance for homogenous loans based on environmental factors. The allowance for loans 90 days or more delinquent is based on the loss history of loans that have become 90 days or more delinquent. We apply a historical loss factor to homogeneous pools of loans that are 90 days or more delinquent. The allowance for homogeneous loans based on historical losses is a rolling three -year average of actual losses incurred, adjusted for a loss realization period, applied to homogenous pools of loans categorized by similar risk characteristics, not including loans that are 90 days or more delinquent. The allocation of the allowance for loan losses is inherently subjective, and the entire allowance for loan losses is available to absorb loan losses regardless of the nature of the loss. Personal Banking loans are charged-off or charged down when they become 180 days delinquent, unless the borrower has filed for bankruptcy. Business Banking loans are charged-off or charged down when, in our opinion, they are no longer collectible or when it has been determined that the collateral value no longer supports the carrying value of the loan, for loans that are collateral dependent. We have not made any material changes to our methodology for the calculation of the allowance for loan losses during the current year. (g) Real Estate Owned Real estate owned is comprised of property either acquired through foreclosure or voluntarily conveyed by borrowers. These assets are recorded on the date acquired at the lower of the loan balance or fair value of the collateral, less estimated disposition costs, with the fair value being determined by an appraisal. Any initial write-down is charged to the allowance for loan losses. Subsequently, foreclosed assets are valued at the lower of the amount recorded at acquisition date or the current fair value, less estimated disposition costs. Any subsequent write-down or gains or losses realized from the disposition of such property are credited or charged to noninterest income. (h) Premises and Equipment Premises and equipment are carried at cost, less accumulated depreciation and amortization. Depreciation is accumulated on a straight-line basis over the estimated useful lives of the related assets. Estimated lives range from three to 39 years . Amortization of leasehold improvements is accumulated on a straight-line basis over the terms of the related leases or the useful lives of the related assets, whichever is shorter. (i) Goodwill Goodwill is generated from the premium paid for an acquisition and is allocated to reporting units, which are either the Company’s reportable segments or one level below. Goodwill is not subject to amortization but is tested for impairment at least annually and possibly more frequently if certain events occur or changes in circumstances arise. Impairment testing requires that the fair value of each reporting unit be compared to its carrying amount, including goodwill. Reporting units are identified based upon analyzing each individual operating segment. A reporting unit is defined as a distinct, separately identifiable component of an operating segment for which complete, discrete financial information is available that management regularly reviews. Determining the fair value of a reporting unit requires a high degree of subjective judgment, including developing cash flow projections, selecting appropriate discount rates, identifying relevant market comparables, incorporating general economic and market conditions and selecting an appropriate control premium. The selection and weighting of the various fair value techniques may result in a higher or lower fair value. Judgment is applied in determining the weightings that are most representative of fair value. We conducted our annual goodwill impairment assessment as of June 30 th through the assistance of an independent third party. We valued each reporting unit by using a weighted average of four valuation methodologies; comparable transaction approach, control premium approach, public market peers approach and discounted cash flow approach. Declines in fair value could result in impairment being identified. At June 30, 2016 and 2015 , we did not identify any individual reporting unit where the fair value was less than the carrying value and no other events have occurred since that date that would warrant an updated valuation. Future changes in the economic environment or the operations of the operating units could cause changes to the variables used, which could give rise to declines in the estimated fair value of the reporting units. There were no changes in our operations that would cause us to update the goodwill impairment tests performed as of June 30, 2016 and 2015 . Accordingly, we have determined that goodwill is not impaired as of December 31, 2016 and 2015 . (j) Core Deposit Intangibles and Other Identifiable Intangibles Through the assistance of an independent third party, we analyze and prepare a core deposit study for all bank acquisitions or other identifiable intangible asset study, such as customer lists, for all non-bank acquisitions. The core deposit study reflects the cumulative present value benefit of acquiring deposits versus an alternative source of funding. The other identifiable intangible asset study reflects the cumulative present value benefit of acquiring the income stream from an existing customer base versus developing new business relationships. Based upon analysis, the amount of the premium related to the core deposits or other identifiable intangibles of the business purchased is calculated along with the estimated life of the intangible. The intangible, which is recorded in other intangible assets, is then amortized to expense on an accelerated basis over an approximate life of typically between 7 years to 11 years . (k) Bank-Owned Life Insurance We own insurance on the lives of a certain group of key employees and directors. The policies were purchased to help offset the increase in the costs of various benefit plans, including healthcare, as well as the directors deferred compensation plan. The cash surrender value of these policies is included as an asset on the consolidated statements of financial condition, and any increases in the cash surrender value are recorded as tax-free noninterest income on the consolidated statements of income. In the event of the death of an insured individual under these policies, after distribution to the insured’s beneficiaries, if any, we receive a tax-free death benefit, which is recorded as noninterest income. (l) Deposits Interest on deposits is accrued and charged to expense monthly and is paid or credited in accordance with the terms of the accounts. (m) Pension Plans We maintain multiple noncontributory defined benefit pension plans for substantially all of our employees. The net periodic pension cost has been calculated using service cost, interest cost, expected returns on plan assets and net amortization. (n) Income Taxes We join with our wholly owned subsidiaries in filing a consolidated federal income tax return. In accordance with an intercompany tax allocation agreement, the applicable federal income tax expense or benefit is allocated to each subsidiary based upon taxable income or loss calculated on a separate company basis. Each subsidiary is responsible for payment of its own federal income tax liability or receives reimbursement of federal income tax benefit. In addition, deferred taxes are calculated and maintained on a separate company basis. We account for income taxes under the asset and liability method. The objective of the asset and liability method is to establish deferred tax assets and liabilities for temporary differences between the financial reporting and tax basis of our assets and liabilities based on the tax rates expected to be in effect when such amounts are realized or settled. (o) Stock-Related Compensation We determine the fair value of each option award, estimated on the grant date, using the Black-Scholes-Merton option-pricing model. The Black-Scholes-Merton option-pricing model uses variables including; expected volatilities, expected term, risk-free discount rate and annual rate of quarterly dividends. Expected volatilities are based on historical volatility of the Company’s stock. The expected terms are based upon actual exercise and forfeiture experience of previous option grants. The risk-free rate is based on yields on U.S. Treasury securities of a similar maturity to the expected term of the options. During the year ended December 31, 2016 , we awarded 660,600 stock options to employees and 64,800 stock options to directors. Option awards are generally granted with an exercise price equal to the closing market price of the Company’s stock on the day before the grant date. The options granted in 2016 vest over a ten -year period, with the first vesting occurring on the grant date. New shares are issued when options are exercised. During the year ended December 31, 2016 , we awarded 310,160 common shares to employees and 24,300 common shares to directors. The common share awards granted in 2016 vest over a ten -year period, with the first vesting occurring on the grant date. For additional information regarding grants of stock options and common shares and ESOP distributions see Note 15. On September 30, 2016, the Northwest Savings Bank Employee Stock Ownership Plan ("ESOP") was terminated. As a result, 1,366,574 unallocated ESOP shares were retired to pay-off the ESOP loan due to the Company. The remaining 401,356 unallocated ESOP shares were distributed into the employees' Northwest Savings Bank 401(k) Plan accounts. This distribution resulted in stock-based compensation expense of $6.3 million for the year ended December 31, 2016. Stock-based employee compensation expense related to common share awards of $3.5 million , $3.0 million and $3.0 million was included in income before income taxes during the years ended December 31, 2016 , 2015 and 2014 , respectively. The effect on net income for the years ended December 31, 2016 , 2015 and 2014 was a reduction of $2.2 million , $1.8 million and $1.8 million , respectively. Total compensation expense for unvested stock options of $4.1 million has yet to be recognized as of December 31, 2016 . The weighted average period over which this remaining stock option expense will be recognized is approximately 4.05 years . The fair value of each option grant is estimated on the date of grant using the Black-Scholes-Merton option-pricing model with the following weighted average assumptions: (1) annual rate of quarterly dividends ranging from 3.2% to 5.1% based on historical dividends and market prices; (2) expected volatility of 17.0% to 22.0% based on historical average montly volatility; (3) risk-free discount rates ranging from 1.7% to 3.1% ; and (4) expected lives of seven to nine years based on previous grants. (p) Segment Reporting We have 2 reportable segments, Community Banking and Consumer Finance. See note 22 for related disclosures. (q) Derivative financial instruments — interest rate swaps We recognize all derivative financial instruments as either assets or liabilities in the balance sheet and measure those instruments at fair value. The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. An entity that elects to use hedge accounting is required, at inception, to establish the method it will use for assessing the effectiveness of the hedging derivative and the measurement approach for determining the ineffective aspect of the hedge. Those methods must be consistent with our approach to managing risk. We utilize interest rate swap agreements as part of the management of interest rate risk to hedge the interest rate risk on our trust preferred debentures. Amounts receivable or payable are recognized as accrued under the terms of the agreements and the differential is recorded as an adjustment to interest expense. The interest rate swaps are designated as cash flow hedges, with the effective portion of the derivative’s unrealized gain or loss recorded as a component of other comprehensive income. The ineffective portion of the unrealized gain or loss, if any, would be recorded in other expense. See note 23 for related disclosures. (r) Off-Balance-Sheet Instruments In the normal course of business, we extend credit in the form of loan commitments, undisbursed lines of credit, and standby letters of credit. These off-balance-sheet instruments involve, to various degrees, elements of credit and interest rate risk not reported in the consolidated statement of financial condition. We utilize the same underwriting standards for these instruments as other extensions of credit. (s) Use of Estimates The preparation of financial statements, in conformity with accounting principles generally accepted in the United States of America, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amount of revenues and expenses during the reporting period. The estimates and assumptions that we deem important to our financial statements relate to the allowance for loan losses, the accounting treatment and valuation of our investment securities portfolio, the analysis of the carrying value of goodwill and income taxes. These estimates and assumptions are based on management’s best estimates and judgment and we evaluate them using historical experience and other factors, including the current economic environment. We adjust our estimates and assumptions when facts and circumstances dictate. As future events cannot be determined, actual results could differ significantly from our estimates. (t) Reclassification of Prior Years’ Statements Certain items previously reported have been reclassified to conform with the current year’s reporting format.

Recent Accounting Pronouncement

Recent Accounting Pronouncements	12 Months Ended
	Dec. 31, 2016
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-9, “Revenue from Contracts with Customers (Topic 606)”. This guidance supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance. The core principle of this guidance requires an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services and provides five steps to be analyzed to accomplish the core principle. This guidance is effective retrospectively for annual reporting periods beginning after December 15, 2017, including interim periods within those years and early adoption is not permitted. We are currently evaluating the impact this standard will have on our results of operations and financial position. In January 2016 the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10)” . This guidance requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. Additionally, this guidance requires entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes and eliminates the requirement for public business entities 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. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We are currently evaluating the impact this standard will have on our results of operations and financial position. In February 2016 the FASB issued ASU 2016-2, “Leases” . This guidance requires a lessee to recognize in the statement of financial condition a liability to make lease payments and a right-of-use asset representing the right to use the underlying asset for the term of the lease. Optional periods should only be recognized if the lessee is reasonably certain to exercise the option. For leases with a term of twelve months or less, the lessee is permitted not to recognize lease assets and lease liabilities and should recognize lease expense for such leases generally on a straight-line basis over the term of the lease. This guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those years and early adoption is permitted. We are currently evaluating the impact this standard will have on our results of operations and financial position. In March 2016 the FASB issued ASU 2016-08, “Principal Versus Agent Considerations” . This guidance clarifies the implementation guidance on principal versus agent considerations of ASU 2014-09 "Revenue from Contracts with Customers (Topic 606)" . When another party is involved in providing goods or services to a customer, an entity is required to determine whether the nature of its promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for that good or service to be provided by the other party (that is, the entity is an agent). When (or as) an entity that is a principal satisfies a performance obligation, the entity recognizes revenue in the gross amount of consideration to which it expects to be entitled in exchange for the specified good or service transferred to the customer. When (or as) an entity that is an agent satisfies a performance obligation, the entity recognizes revenue in the amount of any fee or commission to which it expects to be entitled in exchange for arranging for the specified good or service to be provided by the other party. This guidance is effective retrospectively for annual reporting periods beginning after December 15, 2017, including interim periods within those years and early adoption is not permitted. We are currently evaluating the impact this standard will have on our results of operations and financial position. In March 2016 the FASB issued ASU 2016-09, “Improvements to Employee Share-based Payment Accounting” . This guidance is part of the FASB's Simplification Initiative and simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, including interim periods within those years and early adoption is permitted. We do not expect that this standard will have a material impact on our results of operations or financial position. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326)-Measurement of Credit Losses on Financial Instruments , which eliminates the probable initial recognition threshold for credit losses requiring, instead, that all financial assets (or group of financial assets) measured at amortized cost be presented at the net amount expected to be collected inclusive of the entity’s current estimate of all lifetime expected credit losses. This guidance also applies to certain off-balance-sheet credit exposures such as unfunded commitments and non-derivative financial guarantees. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) in order to present the net carrying value at the amount expected to be collected on the financial asset. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The income statement under this guidance will reflect the initial recognition of current expected credit losses for newly recognized assets, as well as any increases or decreases of expected credit losses that have occurred during the period. This guidance retains many currently-existing disclosures related to the credit quality of an entity’s assets and the related allowance for credit losses amended to reflect the change to an expected credit loss methodology, as well as enhanced disclosures to provide information to users at a more disaggregated level. Upon adoption, ASU 2016-13 provides for a modified retrospective transition by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is effective, except for debt securities for which an other-than-temporary impairment has previously been recognized. For these debt securities, a prospective transition is provided in order to maintain the same amortized cost prior to and subsequent to the effective date of the ASU. This guidance is effective for annual reporting periods beginning after December 15, 2019, and interim periods within those annual periods with early adoption permitted for fiscal years beginning after December 15, 2018, and interim periods within those annual periods. We are currently evaluating the impact this standard will have on our results of operations and financial position.

Acquisition

Acquisition	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Acquisition	Acquisition On September 9, 2016, Northwest, completed the acquisition of 18 branches located in Erie and Niagara Counties, New York and certain related assets, and the assumption of certain related liabilities, pursuant to the Purchase and Sale Agreement with KeyCorp, First Niagara Financial Group, Inc. (“FNFG”), and First Niagara Financial Group’s wholly-owned subsidiaries, First Niagara Bank, National Association and First Niagara Securities, Inc., dated April 28, 2016. The Company also acquired certain wealth management relationships, which included approximately $450.0 million of assets under management. While the branch acquisition is considered a purchase of a business for accounting purposes, pro forma income statement information is not presented because the branch acquisition does not represent the acquisition of a business which has continuity both before and after the acquisition. The following table shows the assets acquired, and the liabilities assumed that were recorded at fair value on the date of acquisition: Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value (1) Cash and cash equivalents (2) $ 1,103,372 Loans 455,857 Core deposit intangible 25,732 Wealth Management intangible 1,143 Other assets 16,978 Total assets acquired 1,603,082 Deposits (1,642,846 ) Other liabilities (5,403 ) Total liabilities assumed (1,648,249 ) Goodwill $ 45,167 (1) Preliminary estimates of fair value have been recorded. (2) Amount is net of $76.5 million deposit premium paid to FNFG. The fair value of loans acquired was estimated by utilizing a methodology wherein similar loans were aggregated into pools. Cash flows for each pool were determined by estimating future credit losses and the rate of prepayments. Projected monthly cash flows were then discounted to present value based on a market rate for similar loans. We did not acquire any purchased credit impaired loans which would require accounting under ASC 310-30. The $25.7 million core deposit and the $1.1 million wealth management intangible assets recognized as part of the branch acquisition are being amortized over their estimated useful lives of approximately 11 and 7 years, respectively, using an accelerated method. The goodwill, which is not amortized for book purposes, was assigned to the Community Banking segment and is deductible for tax purposes. The fair value of savings and transaction deposit accounts acquired was assumed to approximate the carrying value as these accounts have no stated maturity and are payable on demand. Certificates of deposit were valued by projecting out the expected cash flows based on the remaining contractual terms of the certificate of deposit. These cash flows were discounted based on a market rate for a certificate of deposit with a corresponding remaining maturity. Direct costs related to the branch acquisition were expensed as incurred and amounted to $9.2 million for the year ended December 31, 2016, which includes technology and communications costs, professional services, marketing and advertising, and other noninterest expenses.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities Marketable securities available-for-sale at December 31, 2016 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Debt issued by the U.S. government and agencies: Due in one year or less $ 6 — — 6 Debt issued by government sponsored enterprises: 15500 3 -48 15.45 Due in one year or less 74,980 5 (33 ) 74,952 Due after one year through five years 220,937 203 (2,504 ) 218,636 Due after five years through ten years 585 — (3 ) 582 Due after ten years — — — — Equity securities 3,351 1,095 (6 ) 4,440 Municipal securities: Due in one year or less 2,449 7 — 2,456 Due after one year through five years 9,448 105 (21 ) 9,532 Due after five years through ten years 11,794 137 (1 ) 11,930 Due after ten years 38,141 1,027 (16 ) 39,152 Corporate debt issues: Due after ten years 14,367 2,935 (322 ) 16,980 Residential mortgage-backed securities: Fixed rate pass-through 175,398 1,849 (2,680 ) 174,567 Variable rate pass-through 43,587 2,007 (6 ) 45,588 Fixed rate non-agency CMOs 100 1 — 101 Fixed rate agency CMOs 165,535 185 (3,455 ) 162,265 Variable rate agency CMOs 64,874 306 (167 ) 65,013 Total residential mortgage-backed securities 449,494 4,348 (6,308 ) 447,534 Total marketable securities available-for-sale $ 825,552 9,862 (9,214 ) 826,200 Marketable securities held to maturity at December 31, 2016 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Municipal securities: Due after five years through ten years $ — — — — Due after ten years 4,808 65 — 4,873 Residential mortgage-backed securities: Fixed rate pass-through 4,807 217 — 5,024 Variable rate pass-through 2,848 58 — 2,906 Fixed rate agency CMOs 6,674 94 — 6,768 Variable rate agency CMOs 841 14 — 855 Total residential mortgage-backed securities 15,170 383 — 15,553 Total marketable securities held-to-maturity $ 19,978 448 — 20,426 Marketable securities available-for-sale at December 31, 2015 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Debt issued by the U.S. government and agencies: Due in one year or less $ 11 — — 11 Debt issued by government sponsored enterprises: Due in one year or less 15,500 3 (48 ) 15,455 Due after one year through five years 257,463 298 (1,395 ) 256,366 Due after five years through ten years 12,721 14 (23 ) 12,712 Due after ten years 9,815 135 (43 ) 9,907 Equity securities 1,400 500 (6 ) 1,894 Municipal securities: Due in one year or less 1,684 8 — 1,692 Due after one year through five years 14,327 117 (4 ) 14,440 Due after five years through ten years 12,400 323 — 12,723 Due after ten years 52,286 1,727 — 54,013 Corporate debt issues: Due after ten years 14,463 2,417 (405 ) 16,475 Residential mortgage-backed securities: Fixed rate pass-through 118,266 2,480 (420 ) 120,326 Variable rate pass-through 54,292 2,616 (7 ) 56,901 Fixed rate non-agency CMOs 2,519 230 — 2,749 Fixed rate agency CMOs 215,719 389 (3,881 ) 212,227 Variable rate agency CMOs 86,090 476 (52 ) 86,514 Total residential mortgage-backed securities 476,886 6,191 (4,360 ) 478,717 Total marketable securities available-for-sale $ 868,956 11,733 (6,284 ) 874,405 Marketable securities held to maturity at December 31, 2015 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Municipal securities: Due after five years through ten years $ 274 1 — 275 Due after ten years 6,336 239 — 6,575 Residential mortgage-backed securities: Fixed rate pass-through 6,458 351 — 6,809 Variable rate pass-through 3,618 41 — 3,659 Fixed rate agency CMOs 14,033 219 — 14,252 Variable rate agency CMOs 970 12 — 982 Total residential mortgage-backed securities 25,079 623 — 25,702 Total marketable securities held-to-maturity $ 31,689 863 — 32,552 The following table presents information regarding the issuers and the carrying values of our mortgage-backed securities at December 31, 2016 and 2015 : December 31, 2016 2015 Residential mortgage backed securities: FNMA $ 210,373 234,204 GNMA 42,221 48,283 FHLMC 202,822 209,788 SBA 6,608 8,166 Other (including non-agency) 680 3,355 Total residential mortgage-backed securities $ 462,704 503,796 Marketable securities having a carrying value of $200.9 million at December 31, 2016 , were pledged under collateral agreements. During the year ended December 31, 2016 , we sold marketable securities classified as available-for-sale for $2.0 million , with gross realized gains of $268,000 and gross realized losses of $0 . During the year ended December 31, 2015 , we sold marketable securities classified as available-for-sale for $1.2 million , with gross realized gains of $121,000 and gross realized losses of $67,000 . During the year ended December 31, 2014 , we sold marketable securities classified as available-for-sale for $7.9 million with gross realized gains of $4.4 million and gross realized losses of $0 . During the years ended December 31, 2016 , 2015 and 2014 , we did not recognized non-cash credit related other-than-temporary-impairment in our investment portfolio. The following table shows the fair value and gross unrealized losses on investment securities, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position at December 31, 2016 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ 238,003 (2,448 ) 9,205 (92 ) 247,208 (2,540 ) Corporate debt issues — — 2,107 (322 ) 2,107 (322 ) Equity securities — — 544 (6 ) 544 (6 ) Municipal securities 5,621 (37 ) 66 (1 ) 5,687 (38 ) Residential mortgage-backed securities - agency 213,662 (3,837 ) 87,723 (2,471 ) 301,385 (6,308 ) Total temporarily impaired securities $ 457,286 (6,322 ) 99,645 (2,892 ) 556,931 (9,214 ) The following table shows the fair value and gross unrealized losses on investment securities, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position at December 31, 2015 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ 143,751 (723 ) 92,961 (786 ) 236,712 (1,509 ) Corporate debt issues — — 2,021 (405 ) 2,021 (405 ) Equity securities 544 (6 ) — — 544 (6 ) Municipal securities 7,505 (4 ) — — 7,505 (4 ) Residential mortgage-backed securities - agency 122,109 (598 ) 149,889 (3,762 ) 271,998 (4,360 ) Total temporarily impaired securities $ 273,909 (1,331 ) 244,871 (4,953 ) 518,780 (6,284 ) We perform an assessment to determine whether there have been any events or economic circumstances that indicate a security which has an unrealized loss is impaired other-than-temporarily. The assessment considers many factors including the severity and duration of the impairment; recent events specific to the issuer or industry; and for debt securities, external credit ratings, underlying collateral position and recent downgrades. For asset backed securities, we evaluate current characteristics of each security such as delinquency and foreclosure levels, credit enhancement and projected losses and coverage. It is possible that the underlying collateral of these securities will perform worse than current expectations, which may lead to adverse changes in cash flows on these securities and potential future losses. Events that may trigger material declines in fair values for these securities in the future would be, but are not limited to: deterioration of credit metrics, significantly higher levels of default and severity of loss on the underlying collateral, deteriorating credit enhancement and loss coverage ratios, or further illiquidity. For debt securities, credit related other-than-temporary impairment is recognized in earnings, while noncredit related other-than-temporary impairment on securities not expected to be sold, or otherwise disposed of, is recognized in other comprehensive income. We assert that we do not have the intent to sell these securities and it is more likely than not that we will not have to sell these securities before a recovery of our cost basis. For these reasons, we consider the unrealized losses to be temporary impairment losses. There are approximately 154 positions that are temporarily impaired at December 31, 2016 . The aggregate carrying amount of cost-method investments, including both held-to-maturity and available-for-sale, at December 31, 2016 was $846.2 million , of which all were evaluated for impairment. The following table sets forth the categories of investment securities as of December 31, 2016 on which other-than-temporary impairment charges have been recorded in earnings: Total Accumulated Category Amortized cost Fair value Unrealized gain impairment charges Freddie Mac preferred shares $ 1 27 26 (119 ) Trust preferred investments 11,033 13,968 2,935 (7,942 ) Total $ 11,034 13,995 2,961 (8,061 ) The table below shows a cumulative roll forward of credit related impairment losses recognized in earnings for debt securities held and not intended to be sold: December 31, 2016 2015 Beginning balance as of January 1, (1) $ 8,436 8,894 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — Reduction for losses realized during the year (494 ) (98 ) Reduction for securities called realized during the year — (360 ) Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — Ending balance as of December 31, $ 7,942 8,436 (1) The beginning balance represents credit losses included in other-than-temporary impairment charges recognized on debt securities in prior periods.

Loans Receivable and Allowance

Loans Receivable and Allowance for Loan Losses	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Loans Receivable and Allowance for Loan Losses	Loans Receivable and Allowance for Loan Losses Loans receivable at December 31, 2016 and 2015 are summarized in the table below: December 31, 2016 December 31, Originated Acquired Total Originated Acquired Total Personal Banking: Residential mortgage loans $ 2,582,218 133,511 2,715,729 2,695,561 45,716 2,741,277 Home equity loans 1,026,315 302,457 1,328,772 1,055,907 131,199 1,187,106 Consumer loans 467,637 163,622 631,259 313,220 197,397 510,617 Total Personal Banking 4,076,170 599,590 4,675,760 4,064,688 374,312 4,439,000 Commercial Banking: Commercial real estate loans 2,140,678 372,991 2,513,669 2,094,710 429,564 2,524,274 Commercial loans 481,543 75,676 557,219 372,540 65,175 437,715 Total Commercial Banking 2,622,221 448,667 3,070,888 2,467,250 494,739 2,961,989 Total loans receivable, gross 6,698,391 1,048,257 7,746,648 6,531,938 869,051 7,400,989 Deferred loan costs 20,081 2,294 22,375 14,806 5,259 20,065 Allowance for loan losses (55,293 ) (5,646 ) (60,939 ) (60,970 ) (1,702 ) (62,672 ) Undisbursed loan proceeds: Residential mortgage loans (11,638 ) — (11,638 ) (10,778 ) — (10,778 ) Commercial real estate loans (168,595 ) (2,985 ) (171,580 ) (159,553 ) (13,287 ) (172,840 ) Commercial loans (26,168 ) (2,290 ) (28,458 ) (11,132 ) (4,183 ) (15,315 ) Total loans receivable, net $ 6,456,778 1,039,630 7,496,408 6,304,311 855,138 7,159,449 As of December 31, 2016 , 2015 and 2014 , we serviced loans for others approximating $918.9 million , $776.0 million and $734.9 million , respectively. These loans serviced for others are not our assets and are not included in our financial statements. As of December 31, 2016 and 2015 , approximately 62% and 65% , respectively, of our loan portfolio was secured by properties located in Pennsylvania. We do not believe we have significant concentrations of credit risk to any one group of borrowers given our underwriting and collateral requirements. Loans receivable as of December 31, 2016 and 2015 include $2.755 billion and $2.417 billion , respectively, of adjustable rate loans and $4.992 billion and $4.984 billion , respectively, of fixed rate loans. Acquired loans are initially measured at fair value and subsequently accounted for under either Accounting Standards Codification (“ASC”) Topic 310-30 " Accounting for Purchased Loans with Deteriorated Credit Quality" or ASC Topic 310-20 "Nonrefundable Fees and Other Costs . The following table provides information related to the outstanding principal balance and related carrying value of acquired loans for the dates indicated: December 31, December 31, 2016 2015 Acquired loans evaluated individually for future credit losses: Outstanding principal balance $ 16,108 21,069 Carrying value 12,665 16,867 Acquired loans evaluated collectively for future credit losses: Outstanding principal balance 1,040,378 848,194 Carrying value 1,032,611 839,973 Total acquired loans: Outstanding principal balance 1,056,486 869,263 Carrying value 1,045,276 856,840 The following table provides information related to the changes in the accretable discount, which includes income recognized from contractual cash flows for the dates indicated: Total Balance at December 31, 2014 $ — LNB Bancorp, Inc. acquisition 1,672 Accretion (377 ) Net reclassification from nonaccretable yield 724 Balance at December 31, 2015 2,019 Accretion (1,170 ) Net reclassification from nonaccretable yield 1,338 Balance at December 31, 2016 $ 2,187 The following table provides information related to purchased credit impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2016 : Carrying value Outstanding principal balance Related impairment reserve Average recorded investment in impaired loans Interest income/ accretion recognized Personal Banking: Residential mortgage loans $ 1,319 2,062 204 1,650 202 Home equity loans 1,363 2,669 8 1,724 185 Consumer loans 136 303 3 201 51 Total Personal Banking 2,818 5,034 215 3,575 438 Commercial Banking: Commercial real estate loans 9,596 10,809 52 10,942 721 Commercial loans 251 265 — 249 11 Total Commercial Banking 9,847 11,074 52 11,191 732 Total $ 12,665 16,108 267 14,766 1,170 The following table provides information related to purchased credit impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2015 : Carrying Outstanding Related Average Interest Personal Banking: Residential mortgage loans 1,981 2,910 14 2,083 41 Home equity loans 2,084 3,455 6 2,222 51 Consumer loans 267 492 2 305 18 Total Personal Banking 4,332 6,857 22 4,610 110 Commercial Banking: Commercial real estate loans 12,288 13,946 353 12,867 249 Commercial loans 247 266 — 335 18 Total Commercial Banking 12,535 14,212 353 13,202 267 Total 16,867 21,069 375 17,812 377 The following table provides information related to changes in the allowance for losses on loans receivable for the year ended December 31, 2016 : Balance Provision Charge-offs Recoveries Balance Originated loans: Personal Banking: Residential mortgage loans $ 4,656 2,906 (3,228 ) 286 4,692 Home equity loans 3,486 293 (1,090 ) 342 3,941 Consumer loans 7,974 9,052 (10,225 ) 1,659 7,488 Total Personal Banking 16,116 12,251 (14,543 ) 2,287 16,121 Commercial Banking: Commercial real estate loans 23,667 (9,819 ) (2,403 ) 3,541 32,348 Commercial loans 15,510 4,834 (4,165 ) 2,340 12,501 Total Commercial Banking 39,177 (4,985 ) (6,568 ) 5,881 44,849 Total originated loans 55,293 7,266 (21,111 ) 8,168 60,970 Acquired loans: Personal Banking: Residential mortgage loans 71 146 (252 ) 159 18 Home equity loans 1,047 2,065 (1,449 ) 330 101 Consumer loans 653 1,072 (680 ) 151 110 Total Personal Banking 1,771 3,283 (2,381 ) 640 229 Commercial Banking: Commercial real estate loans 3,008 2,116 (1,337 ) 790 1,439 Commercial loans 867 877 (52 ) 8 34 Total Commercial Banking 3,875 2,993 (1,389 ) 798 1,473 Total acquired loans 5,646 6,276 (3,770 ) 1,438 1,702 Total $ 60,939 13,542 (24,881 ) 9,606 62,672 The following table provides information related to changes in the allowance for losses on loans receivable for the year ended December 31, 2015 : Balance Provision Charge-offs Recoveries Balance Originated loans: Personal Banking: Residential mortgage loans $ 4,692 (96 ) (1,057 ) 264 5,581 Home equity loans 3,941 693 (1,716 ) 414 4,550 Consumer loans 7,488 7,985 (8,073 ) 1,458 6,118 Total Personal Banking 16,121 8,582 (10,846 ) 2,136 16,249 Commercial Banking: Commercial real estate loans 32,348 540 (5,741 ) 4,160 33,389 Commercial loans 12,501 2,768 (7,814 ) 4,032 13,515 Total Commercial Banking 44,849 3,308 (13,555 ) 8,192 46,904 Unallocated — (4,365 ) — — 4,365 Total originated loans 60,970 7,525 (24,401 ) 10,328 67,518 Acquired loans: Personal Banking: Residential mortgage loans 18 47 (69 ) 40 — Home equity loans 101 247 (708 ) 562 — Consumer loans 110 188 (201 ) 123 — Total Personal Banking 229 482 (978 ) 725 — Commercial Banking: Commercial real estate loans 1,439 1,545 (585 ) 479 — Commercial loans 34 160 (369 ) 243 — Total Commercial Banking 1,473 1,705 (954 ) 722 — Total acquired loans 1,702 2,187 (1,932 ) 1,447 — Total $ 62,672 9,712 (26,333 ) 11,775 67,518 The following table provides information related to changes in the allowance for losses on loans receivable for the year ended December 31, 2014 : Balance Provision Charge-offs Recoveries Balance Personal Banking: Residential mortgage loans $ 5,581 (556 ) (2,181 ) 443 7,875 Home equity loans 4,550 (1,106 ) (1,783 ) 194 7,245 Consumer loans 6,118 5,864 (6,423 ) 1,190 5,487 Total Personal Banking 16,249 4,202 (10,387 ) 1,827 20,607 Commercial Banking: Commercial real estate loans 33,389 4,417 (8,422 ) 2,195 35,199 Commercial loans 13,515 11,992 (11,936 ) 2,579 10,880 Total Commercial Banking 46,904 16,409 (20,358 ) 4,774 46,079 Unallocated 4,365 (297 ) — — 4,662 Total $ 67,518 20,314 (30,745 ) 6,601 71,348 While we use available information to provide for losses, future additions to the allowance may be necessary based on changes in economic conditions. In addition, various regulatory agencies, as an integral part of their examination process, periodically review our allowance for loan losses. Such agencies may require us to recognize additions to the allowance based on their judgments about information available to them at the time of their examination. Management believes, to the best of their knowledge, that all known losses as of the balance sheet dates have been recorded. The following table provides information related to the loan portfolio by portfolio segment and by class of financing receivable as of December 31, 2016 : Recorded investment in loans receivable Allowance for loan losses Recorded investment in loans on nonaccrual (1) Recorded investment in loans 90 days or more past maturity and still accruing TDRs (1) Allowance for TDRs Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,714,764 4,727 18,264 — 7,299 708 — Home equity loans 1,328,772 4,533 7,865 — 1,813 450 4 Consumer loans 642,961 8,627 5,109 85 — — — Total Personal Banking 4,686,497 17,887 31,238 85 9,112 1,158 4 Commercial Banking: Commercial real estate loans 2,342,089 26,675 38,724 564 24,483 2,072 417 Commercial loans 528,761 16,377 9,574 — 9,331 1,360 17 Total Commercial Banking 2,870,850 43,052 48,298 564 33,814 3,432 434 Total $ 7,557,347 60,939 79,536 649 42,926 4,590 438 (1) Includes $16.3 million of nonaccrual TDRs. The following table provides information related to the loan portfolio by portfolio segment and by class of financing receivable as of December 31, 2015 : Recorded investment in loans receivable Allowance for loan losses Recorded investment in loans on nonaccrual (1) Recorded TDRs (1) Allowance for TDRs Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,740,892 4,710 19,772 4 6,360 1,189 — Home equity loans 1,187,106 4,042 7,522 — 2,298 605 — Consumer loans 520,289 7,598 3,452 976 — — — Total Personal Banking 4,448,287 16,350 30,746 980 8,658 1,794 — Commercial Banking: Commercial real estate loans 2,351,434 33,787 33,421 206 31,970 2,257 241 Commercial loans 422,400 12,535 7,495 148 10,487 631 79 Total Commercial Banking 2,773,834 46,322 40,916 354 42,457 2,888 320 Total $ 7,222,121 62,672 71,662 1,334 51,115 4,682 320 (1) Includes $21.1 million of nonaccrual TDRs. A loan is considered to be impaired, when, based on current information and events it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement including both contractual principal and interest payments. This includes non-accrual loans, loans more than 90 days delinquent and still accruing interest, loans for which we perform an impairment review and TDRs. Impairment is measured using one of three methods: (1) the present value of expected future cash flows discounted at the loan’s effective interest rate; (2) the loan’s observable market price; or (3) the fair value of collateral if the loan is collateral dependent, less costs of sale or disposition. If the measure of the impaired loan is less than the recorded investment in the loan, a specific allowance is allocated for the impairment. The following table provides information related to the composition of impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2016 : Nonaccrual loans 90 or more days delinquent Nonaccrual loans less than 90 days delinquent Loans less than 90 days delinquent reviewed for impairment TDRs less than 90 days delinquent not included elsewhere Total impaired loans Average recorded investment in impaired loans Interest income recognized on impaired loans Personal Banking: Residential mortgage loans $ 13,169 5,095 — 5,929 24,193 24,483 1,079 Home equity loans 5,552 2,313 — 1,439 9,304 9,234 496 Consumer loans 3,823 1,286 — — 5,109 3,703 166 Total Personal Banking 22,544 8,694 — 7,368 38,606 37,420 1,741 Commercial Banking: Commercial real estate loans 19,264 19,460 3,622 11,582 53,928 64,350 2,864 Commercial loans 3,373 6,201 2,837 3,116 15,527 16,905 991 Total Commercial Banking 22,637 25,661 6,459 14,698 69,455 81,255 3,855 Total $ 45,181 34,355 6,459 22,066 108,061 118,675 5,596 The following table provides information related to the composition of impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2015 : Nonaccrual loans 90 or more days delinquent Nonaccrual loans less than 90 days delinquent Loans less than 90 days delinquent reviewed for impairment TDRs less than 90 days delinquent not included elsewhere Total impaired loans Average recorded investment in impaired loans Interest income recognized on impaired loans Personal Banking: Residential mortgage loans $ 15,810 3,962 — 5,086 24,858 24,554 944 Home equity loans 5,650 1,872 — 1,847 9,369 9,644 497 Consumer loans 2,900 552 — — 3,452 2,977 101 Total Personal Banking 24,360 6,386 — 6,933 37,679 37,175 1,542 Commercial Banking: Commercial real estate loans 16,449 16,972 16,121 16,467 66,009 77,166 3,226 Commercial loans 2,459 5,036 2,014 4,654 14,163 16,187 694 Total Commercial Banking 18,908 22,008 18,135 21,121 80,172 93,353 3,920 Total $ 43,268 28,394 18,135 28,054 117,851 130,528 5,462 The following table provides information related to the composition of impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2014 : Nonaccrual loans 90 or more days delinquent Nonaccrual loans less than 90 days delinquent Loans less than 90 days delinquent reviewed for impairment TDRs less than 90 days delinquent not included elsewhere Total impaired loans Average recorded investment in impaired loans Interest income recognized on impaired loans Personal Banking: Residential mortgage loans $ 17,696 3,498 — 5,845 27,039 28,227 817 Home equity loans 6,606 2,963 — 1,706 11,275 11,753 485 Consumer loans 2,450 370 — — 2,820 2,383 66 Total Personal Banking 26,752 6,831 — 7,551 41,134 42,363 1,368 Commercial Banking: Commercial real estate loans 11,099 27,548 26,400 12,128 74,337 90,187 3,589 Commercial loans 3,475 4,103 5,266 6,026 21,708 27,088 914 Total Commercial Banking 14,574 31,651 31,666 18,154 96,045 117,275 4,503 Total $ 41,326 38,482 31,666 25,705 137,179 159,638 5,871 The following table provides information related to the evaluation of impaired loans by portfolio segment and by class of financing receivable as of and for the year ended December 31, 2016 : Loans collectively evaluated for impairment Loans individually evaluated for impairment Loans individually evaluated for impairment for which there is a related impairment reserve Related impairment reserve Loans individually evaluated for impairment for which there is no related reserve Personal Banking: Residential mortgage loans $ 2,706,484 8,280 8,280 709 — Home equity loans 1,326,958 1,814 1,814 450 — Consumer loans 642,835 126 126 29 — Total Personal Banking 4,676,277 10,220 10,220 1,188 — Commercial Banking: Commercial real estate loans 2,309,186 32,903 27,594 3,545 5,309 Commercial loans 518,449 10,312 10,242 1,390 70 Total Commercial Banking 2,827,635 43,215 37,836 4,935 5,379 Total $ 7,503,912 53,435 48,056 6,123 5,379 The following table provides information related to the evaluation of impaired loans by portfolio segment and by class of financing receivable as of and for the year ended December 31, 2015 : Loans collectively evaluated for impairment Loans individually evaluated for impairment Loans individually evaluated for impairment for which there is a related impairment reserve Related impairment reserve Loans individually evaluated for impairment for which there is no related reserve Personal Banking: Residential mortgage loans $ 2,733,741 7,151 7,151 1,189 — Home equity loans 1,184,808 2,298 2,298 605 — Consumer loans 520,159 130 130 50 — Total Personal Banking 4,438,708 9,579 9,579 1,844 — Commercial Banking: Commercial real estate loans 2,297,599 53,835 35,937 2,675 17,898 Commercial loans 411,342 11,058 7,673 489 3,385 Total Commercial Banking 2,708,941 64,893 43,610 3,164 21,283 Total $ 7,147,649 74,472 53,189 5,008 21,283 Our loan portfolios include certain loans that have been modified in a TDR, where economic concessions have been granted to borrowers who have experienced financial difficulties. These concessions typically result from our loss mitigation activities and could include: extending the note’s maturity date, permitting interest only payments, reducing the interest rate to a rate lower than current market rates for new debt with similar risk, reducing the principal payment, principal forbearance or other actions. These concessions are applicable to all loan segments and classes. Certain TDRs are classified as nonperforming at the time of restructuring and typically are returned to performing status after considering the borrower’s sustained repayment performance for a reasonable period of at least six consecutive months. When we modify loans in a TDR, we evaluate any possible impairment similar to other impaired loans based on the present value of expected future cash flows, discounted at the contractual interest rate of the original loan agreement, the loan’s observable market price or the current fair value of the collateral, less selling costs, for collateral dependent loans. If we determine that the value of the modified loan is less than the recorded investment in the loan (net of previous charge-offs, deferred loan fees or costs and unamortized premium or discount), impairment is recognized through an allowance estimate or a charge-off to the allowance. In periods subsequent to modification, we evaluate all TDRs, including those that have payment defaults, for possible impairment, using ASC 310-10. As a result, loans modified in a TDR may have the financial effect of increasing the specific allowance associated with the loan. Loans modified in a TDR are closely monitored for delinquency as an early indicator of possible future default. If loans modified in a TDR subsequently default, we evaluate the loan for possible further impairment. The allowance may be increased, adjustments may be made in the allocation of the allowance, partial charge-offs may be taken to further write-down the carrying value of the loan, or the loan may be charged-off completely. The following table provides a roll forward of troubled debt restructurings for the periods indicated: For the years ended December 31, 2016 2015 Number of contracts Amount Number of contracts Amount Beginning TDR balance: 227 $ 51,115 248 $ 61,788 New TDRs 34 6,365 26 8,537 Re-modified TDRs 7 3,414 3 6,386 Net paydowns (9,037 ) (13,270 ) Charge-offs: Residential mortgage loans — — — — Home equity loans — — 4 (159 ) Commercial real estate loans 1 (120 ) 4 (179 ) Commercial loans 2 (142 ) 2 (387 ) Paid-off loans: Residential mortgage loans 4 (151 ) 2 (109 ) Home equity loans (534 ) 5 (194 ) Commercial real estate loans 19 (6,170 ) 15 (9,208 ) Commercial loans 10 (1,814 ) 14 (1,728 ) Transferred to real estate owned Commercial real estate loans — — 1 (362 ) Ending TDR balance: 225 $ 42,926 227 $ 51,115 Accruing TDRs $ 26,580 $ 29,997 Non-accrual TDRs 16,346 21,118 The following table provides information related to troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable during the year ended December 31, 2016 : Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 7 $ 1,199 1,177 114 Home equity loans 7 475 471 110 Consumer loans — — — — Total Personal Banking 14 1,674 1,648 224 Commercial Banking: Commercial real estate loans 7 3,729 3,643 485 Commercial loans 20 4,376 2,218 508 Total Commercial Banking 27 8,105 5,861 993 Total 41 $ 9,779 7,509 1,217 Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings modified within the previous twelve months that have subsequently defaulted: Personal Banking: Residential mortgage loans — $ — — — Home equity loans — — — — Consumer loans — — — — Total Personal Banking — — — — Commercial Banking: Commercial real estate loans 1 429 425 31 Commercial loans 3 533 533 533 Total Commercial Banking 4 962 958 564 Total 4 $ 962 958 564 The following table provides information related to troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable during the year ended December 31, 2015 : Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 6 $ 364 357 21 Home equity loans 3 101 97 21 Consumer loans — — — — Total Personal Banking 9 465 454 42 Commercial Banking: Commercial real estate loans 11 12,258 12,243 1,047 Commercial loans 9 2,200 2,184 156 Total Commercial Banking 20 14,458 14,427 1,203 Total 29 $ 14,923 14,881 1,245 At December 31, 2015, no TDRs that were modified in the previous twelve months had subsequently defaulted. The following table provides information related to troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable during the year ended December 31, 2014 : Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 17 $ 2,802 2,690 210 Home equity loans 6 570 507 1 Consumer loans — — — — Total Personal Banking 23 3,372 3,197 211 Commercial Banking: Commercial real estate loans 11 2,010 1,793 202 Commercial loans 23 7,750 6,818 1,491 Total Commercial Banking 34 9,760 8,611 1,693 Total 57 $ 13,132 11,808 1,904 Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings modified within the previous twelve months that have subsequently defaulted: Personal Banking: Residential mortgage loans 1 $ 78 77 — Home equity loans 1 360 331 1 Consumer loans — — — — Total Personal Banking 2 438 408 1 Commercial Banking: Commercial real estate loans 1 12 5 1 Commercial loans 1 50 64 6 Total Commercial Banking 2 62 69 7 Total 4 $ 500 477 8 The following table provides information for troubled debt restructurings (including re-modified TDRs) by type of modification, by portfolio segment and class of financing receivable during the year ended December 31, 2016 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 7 $ 358 — 771 48 1,177 Home equity loans 7 120 — 3 348 471 Consumer loans — — — — — — Total Personal Banking 14 478 — 774 396 1,648 Commercial Banking: Commercial real estate loans 7 — 425 1,980 1,238 3,643 Commercial loans 20 — 328 1,178 712 2,218 Total Commercial Banking 27 — 753 3,158 1,950 5,861 Total 41 $ 478 753 3,932 2,346 7,509 The following table provides information for troubled debt restructurings (including re-modified TDRs) by type of modification, by portfolio segment and class of financing receivable during the year ended December 31, 2015 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 6 $ 71 — 110 176 357 Home equity loans 3 96 — 1 — 97 Consumer loans — — — — — — Total Personal Banking 9 167 — 111 176 454 Commercial Banking: Commercial real estate loans 11 174 — 11,961 108 12,243 Commercial loans 9 — — 1,264 920 2,184 Total Commercial Banking 20 174 — 13,225 1,028 14,427 Total 29 $ 341 — 13,336 1,204 14,881 The following table provides information related to re-modified troubled debt restructurings by portfolio segment and by class of financing receivable for the year ended December 31, 2016 : Number of re- modified Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans — $ — — — — — Home equity loans 1 — — — 192 192 Consumer loans — — — — — — Total Personal Banking 1 — — — 192 192 Commercial Banking: Commercial real estate loans 2 — — 1,329 173 1,502 Commercial loans 4 — 502 — — 502 Total Commercial Banking 6 — 502 1,329 173 2,004 Total 7 $ — 502 1,329 365 2,196 The following table provides information related to re-modified troubled debt restructurings by portfolio segment and by class of financing receivable for the year ended December 31, 2015 : Number of re- modified Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 1 $ — — — 45 45 Home equity loans 1 83 — — — 83 Consumer loans — — — — — — Total Personal Banking 2 83 — — 45 128 Commercial Banking: Commercial real estate loans 1 — — 6,256 — 6,256 Commercial loans — — — — — — Total Commercial Banking 1 — — 6,256 — 6,256 Total 3 $ 83 — 6,256 45 6,384 The following table provides information related to loan delinquencies as of December 31, 2016 : 30-59 days delinquent 60-89 days delinquent 90 days or greater delinquent Total delinquency Current Total loans 90 days or greater delinquent and accruing (1) Originated loans Personal Banking: Residential mortgage loans $ 26,212 5,806 12,792 44,810 2,536,443 2,581,253 — Home equity loans 5,785 1,305 4,783 11,873 1,014,442 1,026,315 — Consumer loans 8,598 3,204 3,518 15,320 461,725 477,045 — Total Personal Banking 40,595 10,315 21,093 72,003 4,012,610 4,084,613 — Commercial Banking: Commercial real estate loans 7,674 3,674 16,508 27,856 1,944,227 1,972,083 — Commercial loans 1,067 1,957 3,107 6,131 449,244 455,375 — Total Commercial Banking 8,741 5,631 19,615 33,987 2,393,471 2,427,458 — Total originated loans 49,336 15,946 40,708 105,990 6,406,081 6,512,071 — Acquired loans Personal Banking: Residential mortgage loans 1,174 421 829 2,424 131,087 133,511 452 Home equity loans 1,020 258 973 2,251 300,206 302,457 204 Consumer loans 1,270 405 320 1,995 163,921 165,916 15 Total Personal Banking 3,464 1,084 2,122 6,670 595,214 601,884 671 Commercial Banking: Commercial real estate loans 2,703 821 4,762 8,286 361,720 370,006 2,006 Commercial loans 111 124 413 648 72,738 73,386 147 Total Commercial Banking 2,814 945 5,175 8,934 434,458 443,392 2,153 Total acquired loans 6,278 2,029 7,297 15,604 1,029,672 1,045,276 2,824 Total loans $ 55,614 17,975 48,005 121,594 7,435,753 7,557,347 2,824 (1) Represents acquired loans that were originally recorded at fair value upon acquisition. These loans are considered to be accruing because we can reasonably estimate future cash flows on and expect to fully collect the carrying value of these loans. Therefore, we are accreting the difference between the carrying value and their expected cash flows into interest income. The following table provides information related to loan delinquencies as of December 31, 2015 : 30-59 days delinquent 60-89 days delinquent 90 days or greater delinquent Total delinquency Current Total loans 90 days or greater delinquent and accruing (1) Personal Banking: Residential mortgage loans $ 25,503 7,541 15,564 48,608 2,646,568 2,695,176 — Home equity loans 4,870 1,836 5,251 11,957 1,043,950 1,055,907 — Consumer loans 6,092 2,340 2,857 11,289 306,344 317,633 — Total Personal Banking 36,465 11,717 23,672 71,854 3,996,862 4,068,716 — Commercial Banking: Commercial real estate loans 22,212 6,875 14,942 44,029 1,891,128 1,935,157 — Commercial loans 1,703 598 2,449 4,750 356,658 361,408 — Total Commercial Banking 23,915 7,473 17,391 48,779 2,247,786 2,296,565 — Total originated loans 60,380 19,190 41,063 120,633 6,244,648 6,365,281 — Acquired loans Personal Banking: Residential mortgage loans 440 249 786 1,475 44,241 45,716 540 Home equity loans 936 642 861 2,439 128,760 131,199 462 Consumer loans 1,009 181 69 1,259 201,397 202,656 26 Total Personal Banking 2,385 1,072 1,716 5,173 374,398 379,571 1,028 Commercial Banking: Commercial real estate loans 2,665 1,353 4,089 8,107 408,170 416,277 2,582 Commercial loans 1,165 — 150 1,315 59,677 60,992 140 Total Commercial Banking 3,830 1,353 4,239 9,422 467,847 477,269 2,722 Total acquired loans 6,215 2,425 5,955 14,595 842,245 856,840 3,750 Total loans $ 66,595 21,615 47,018 135,228 7,086,893 7,222,121 3,750 (1) Represents acquired loans that were originally recorded at fair value upon acquisition. These loans are considered to be accruing because we can reasonably estimate future cash flows on and expect to fully collect the carrying value of these loans. Therefore, we are accreting the difference between the carrying value and their expected cash flows into interest income. Credit quality indicators: We categorize loans into risk categories based on relevant information about the ability of borrowers to service their debt such as: current financial information, historical payment experience, credit documentation, public information, and current economic trends, among other factors. We analyze business loans individually by classifying the loans by credit risk. Relationships greater than or equal to $1.0 million classified as special mention or substandard are reviewed quarterly for further deterioration or improvement to determine if the loan is appropriately classified. We use the following definitions for risk ratings other than pass: Special mention — Loans designated as special mention have specific, well-defined risk issues, which create a high level of uncertainty regarding the long-term viability of the business. Loans in this class are considered to have high-risk characteristics. A special mention loan exhibits material negative financial trends due to company-specific or systemic conditions. If these potential weaknesses are not mitigated, they threaten the borrower’s capacity to meet its debt obligations. Special mention loans still demonstrate sufficient financial flexibility to react to and positively address the root cause of the adverse financial trends without significant deviations from their current business strategy. Their potential weaknesses deserve our close attention and warrant enhanced monitoring. Substandard — Loans classified as substandard are inadequately protected by the current net worth and payment capacity of the obligor or of the collateral pledged, if any. Loans so classified have a well-defined weakness or weaknesses that jeopardize the liquidation of the debt. They are characterized by the distinct possibility that we will sustain some loss if the deficiencies are not corrected. Doubtful — Loans classified as doubtful have all the weaknesses inherent in those classified as substandard. In addition, those weaknesses make collection or liquidation in full highly questionable and improbable. A loan classified as doubtful exhibits discernible loss potential, but a complete loss seems very unlikely. The possibility of a loss on a doubtful loan is high, but because of certain important and reasonably specific pending factors that may strengthen the loan, its classification as an estimated loss is deferred until a more exact status can be determined. Loss — Loans classified as loss are considered uncollectible and of such value that the continuance as a loan is not warranted. A loss classification does not mean that the loan has no recovery or salvage value; instead, it means that it is not practical or desirable to defer writing off all or a portion of a basically worthless loan even though partial recovery may be affected in the future. The following table sets forth information about credit quality indicators as of December 31, 2016 : Pass Special mention Substandard Doubtful Loss Total Originated loans Personal Banking: Residential mortgage loans $ 2,564,988 — 16,265 — — 2,581,253 Home equity loans 1,018,898 — 7,417 — — 1,026,315 Consumer loans 473,950 — 3,095 — — 477,045 Total Personal Banking 4,057,836 — 26,777 — — 4,084,613 Commercial Banking: Commercial real estate loans 1,821,548 36,321 114,214 — — 1,972,083 Commercial loans 401,866 15,203 38,306 — — 455,375 Total Commercial Banking 2,223,414 51,524 152,520 — — 2,427,458 Total originated loans 6,281,250 51,524 179,297 — — 6,512,071 Acquired loans Personal Banking: Residential mortgage loans 131,717 — 1,794 — — 133,511 Home equity loans 300,100 — 2,357 — — 302,457 Consumer loans 165,094 — 822 — — 165,916 Total Personal Banking 596,911 — 4,973 — — 601,884 Commercial Banking: Commercial real estate loans 331,780 7,403 30,823 — — 370,006 Commercial loans 68,127 1,989 3,270 —

Accrued Interest Receivable

Accrued Interest Receivable	12 Months Ended
	Dec. 31, 2016
Interest Receivable and Other Assets [Abstract]
Accrued Interest Receivable	Accrued Interest Receivable Accrued interest receivable as of December 31, 2016 and 2015 is presented in the following table: December 31, 2016 2015 Investment securities $ 1,613 1,852 Mortgage-backed securities 910 960 Loans receivable 19,176 18,260 $ 21,699 21,072

Federal Home Loan Bank Stock

Federal Home Loan Bank Stock	12 Months Ended
	Dec. 31, 2016
Federal Home Loan Banks [Abstract]
Federal Home Loan Bank Stock	Federal Home Loan Bank Stock Northwest Bank is a member of the Federal Home Loan Bank system. As a member, we are required to maintain an investment in the capital stock of the FHLB of Pittsburgh in accordance with their 2015 Capital Plan, at cost, in two subclasses based on the following ranges: Membership stock purchase (Subclass B-1) ranging from 0.05 % to 1.0 % of the member asset value as defined by the FHLB, currently at 0.10 %; and Activity-based stock purchase (Subclass B-2) ranging from 2.0 % to 6.0 % of outstanding advances, currently at 4.0 %; 0.0 % to 6.0 % of acquired member assets, currently at 4.0 %; 0.0 % to 4.0 % of certain letters of credit, currently at 0.75 %; and 0.0 % to 6.0 % of outstanding advance commitments settling more than 30 days after trade, currently at 0.0 %. We received dividends on capital stock during the years ended December 31, 2016 and 2015 of $1.4 million and $2.8 million , respectively. Future dividends may be established at different rates for the two subclasses of capital stock.

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Premises and equipment at December 31, 2016 and 2015 are summarized by major classification in the following table: December 31, 2016 2015 Land and land improvements $ 21,229 23,257 Office buildings and improvements 156,162 153,003 Furniture, fixtures and equipment 120,391 115,576 Leasehold improvements 19,859 19,239 Total, at cost 317,641 311,075 Less accumulated depreciation and amortization (156,456 ) (156,724 ) Premises and equipment, net $ 161,185 154,351 Depreciation and amortization expense for the years ended December 31, 2016 , 2015 and 2014 was $13.7 million , $13.3 million and $12.0 million , respectively. Premises used by certain of our offices are occupied under formal operating lease arrangements. The leases expire on various dates through 2027. Minimum annual rentals by fiscal year are summarized in the following table: 2017 $ 4,846 2018 3,697 2019 2,579 2020 2,015 2021 1,596 Thereafter 5,595 Total $ 20,328 Rental expense for the years ended December 31, 2016 , 2015 and 2014 was $5.3 million , $4.6 million and $4.4 million , respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Other Intangible Assets	Goodwill and Other Intangible Assets The following table provides information for intangible assets subject to amortization for the years ended December 31, 2016 and 2015 : December 31, 2016 2015 Amortizable intangible assets: Core deposit intangibles — gross $ 37,953 30,578 Acquisitions 25,732 7,375 Less: accumulated amortization (34,378 ) (31,192 ) Core deposit intangibles — net $ 29,307 6,761 Customer and Contract intangible assets — gross 8,496 8,234 Acquisitions 1,978 262 Less: accumulated amortization (7,348 ) (6,275 ) Customer and Contract intangible assets — net $ 3,126 2,221 The following information shows the actual aggregate amortization expense for the years ended December 31, 2016 , 2015 and 2014 as well as the estimated aggregate amortization expense, based upon current levels of intangible assets, for each of the five succeeding fiscal years: For the year ended December 31, 2014 $ 1,323 For the year ended December 31, 2015 1,688 For the year ended December 31, 2016 4,259 For the year ending December 31, 2017 6,764 For the year ending December 31, 2018 5,848 For the year ending December 31, 2019 4,933 For the year ending December 31, 2020 4,017 For the year ending December 31, 2021 3,188 The following table provides information for the changes in the carrying amount of goodwill: Community Banks Consumer Finance Total Balance at December 31, 2014 $ 173,710 1,613 175,323 Goodwill acquired - LNB 86,238 — 86,238 Goodwill acquired - Petruso Insurance Agency 175 — 175 Balance at December 31, 2015 260,123 1,613 261,736 Goodwill acquired - FNFG 45,167 — 45,167 Goodwill acquired - Best Insurance Agency 404 — 404 Goodwill acquired - Winan Insurance Agency 113 — 113 Balance at December 31, 2016 $ 305,807 1,613 307,420 We have determined that goodwill is not impaired as of December 31, 2016 and 2015 . There were no changes in our operations that would cause us to update the goodwill impairment test performed as of June 30, 2016 .

Deposits

Deposits	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Deposits	Deposits Deposit balances at December 31, 2016 and 2015 are shown in the table below: December 31, 2016 2015 Savings deposits $ 1,622,879 1,386,017 Interest-bearing demand deposits 1,428,317 1,080,086 Noninterest-bearing demand deposits 1,448,972 1,177,256 Money market demand accounts 1,841,567 1,274,504 Time deposits 1,540,586 1,694,718 Total deposits $ 7,882,321 6,612,581 The aggregate amount of time deposits with a minimum denomination of $100,000 at December 31, 2016 and 2015 was $451.6 million and $518.7 million , respectively. Generally, deposits in excess of $250,000 are not federally insured. At December 31, 2016 we had $1.580 billion of deposits in accounts exceeding $250,000 . The following table summarizes the contractual maturity of time deposits at December 31, 2016 and 2015 : December 31, 2016 2015 Due within 12 months $ 836,525 929,351 Due between 12 and 24 months 311,976 448,497 Due between 24 and 36 months 153,708 205,635 Due between 36 and 48 months 90,777 21,414 Due between 48 and 60 months 134,687 78,796 After 60 months 12,913 11,025 Total time deposits $ 1,540,586 1,694,718 The following table summarizes the interest expense incurred on the respective deposits for the years ended December 31, 2016 , 2015 and 2014 : Years ended December 31, 2016 2015 2014 Savings deposits $ 3,218 3,387 3,286 Interest-bearing demand deposits 462 568 587 Money market demand accounts 3,621 3,222 3,174 Time deposits 16,164 16,878 18,275 Total interest expense $ 23,465 24,055 25,322

Borrowed Funds

Borrowed Funds	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Borrowed Funds	Borrowed Funds Borrowed funds at December 31, 2016 and 2015 are presented in the following table: December 31, 2016 2015 Amount Average rate Amount Average rate Term notes payable to the FHLB of Pittsburgh: Due within one year $ — — % 145,343 3.24 % Due between one and two years — — % 125,000 3.68 % Due between two and three years — — % 140,000 3.73 % Due between three and four years — — % 125,000 4.32 % Due between four and five years — — % 95,000 3.65 % Due between five and ten years — — % 120,000 3.68 % — 750,343 Revolving line of credit, FHLB of Pittsburgh — — % 106,000 0.43 % Collateralized borrowings, due within one year 142,899 0.17 % 118,664 0.22 % Total borrowed funds $ 142,899 975,007 Borrowings from the FHLB of Pittsburgh, if any, are secured by our residential first mortgage and other qualifying loans. Certain of these borrowings are subject to restrictions or penalties in the event of prepayment. The revolving line of credit with the FHLB of Pittsburgh carries a commitment of $150.0 million . The rate is adjusted daily by the FHLB of Pittsburgh, and any borrowings on this line may be repaid at any time without penalty. The collateralized borrowings are collateralized by various securities held in safekeeping by the FHLB of Pittsburgh. The market value of these securities exceeds the value of the collateralized borrowings. The average amount of collateralized borrowings outstanding in the years ended December 31, 2016 , 2015 and 2014 was $141.6 million , $144.7 million and $155.7 million , respectively. The maximum amount of collateralized borrowings outstanding during the years ended December 31, 2016 , 2015 and 2014 was $158.4 million , $166.4 million and $174.2 million , respectively.

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Total income tax was allocated for the years ended December 31, 2016 , 2015 and 2014 as follows: Years ended December 31, 2016 2015 2014 Income before income taxes $ 21,648 27,960 21,795 Shareholders’ equity for unrealized (loss)/ gain on securities available-for-sale (1,871 ) (85 ) 4,286 Shareholders’ equity for tax benefit for excess of fair value above cost of stock benefit plans (1,425 ) (332 ) (945 ) Shareholders’ equity for pension adjustment (2,455 ) (848 ) (12,985 ) Shareholders’ equity for swap fair value adjustment 539 699 618 Unallocated income tax $ 16,436 27,394 12,769 Income tax expense applicable to income before taxes consists of: Years ended December 31, 2016 2015 2014 Current $ 18,914 21,670 13,200 Deferred 2,734 6,290 8,595 Total income tax expense $ 21,648 27,960 21,795 A reconciliation of the expected federal statutory income tax rate to the effective rate, expressed as a percentage of pretax income for the years ended December 31, 2016 , 2015 and 2014 , is as follows: Years ended December 31, 2016 2015 2014 Expected tax rate 35.0 % 35.0 % 35.0 % Tax-exempt interest income (3.3 )% (3.0 )% (4.1 )% State income tax, net of federal benefit 1.2 % 2.9 % 1.7 % Bank-owned life insurance (2.6 )% (1.7 )% (1.8 )% Dividends on stock plans (2.0 )% (0.8 )% (4.0 )% Low income housing and historic tax credits (1.0 )% (1.4 )% (0.9 )% Non-deductible acquisition expense — % 0.5 % — % ESOP termination 3.4 % — % — % Other (0.3 )% 0.1 % 0.1 % Effective tax rate 30.4 % 31.6 % 26.0 % The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2016 and 2015 are presented below: December 31, 2016 2015 Deferred tax assets: Deferred fee income $ 187 189 Deferred compensation expense 2,893 3,717 Bad debts 18,823 19,478 Other reserves 1,823 — Accrued postretirement benefit cost 641 644 Stock benefit plans 1,085 1,626 Writedown of investment securities 2,875 2,994 Accrued expenses 348 228 Pension and postretirement benefits 18,491 16,035 Unrealized loss on the fair value of derivatives 958 1,496 Purchase accounting 1,215 2,236 Other 153 325 Total deferred tax assets 49,492 48,968 Deferred tax liabilities: Pension expense 8,689 7,557 Unrealized gain on the fair value of securities available-for-sale 252 2,122 Intangible assets 21,927 23,003 Mortgage servicing rights 1,559 120 Fixed assets 8,107 8,731 Other 635 460 Total deferred tax liabilities 41,169 41,993 Net deferred tax asset $ 8,323 6,975 As a result of the FNFG acquisition, deferred tax assets were increased by $ 294,000 related to acquisition accounting tax adjustments. We have determined that no valuation allowance is necessary for the deferred tax assets because it is more likely than not that these assets will be realized through carry-back to taxable income in prior years, future reversals of existing temporary differences, and through future taxable income. We will continue to review the criteria related to the recognition of deferred tax assets on a regular basis. We utilize a comprehensive model to recognize, measure, present and disclose in our financial statements uncertain tax positions that the company has taken or expects to take on a tax return. At December 31, 2016 , there were no unrecognized tax benefits that, if recognized, would favorably affect the effective income tax rate. We recognize interest accrued and penalties (if any) related to unrecognized tax benefits in income tax expense. During the year ended December 31, 2016 , we did not accrue any interest. At December 31, 2016 , we had no amount accrued for interest or the payment of penalties. We are subject to routine audits of our tax returns by the Internal Revenue Service as well as all states in which we conduct business. We are subject to audit by the Internal Revenue Service for the tax periods ended December 31, 2016 , 2015 , 2014 and 2013 and subject to audit by any state in which we conduct business for the tax periods ended December 31, 2016 , 2015 , 2014 and 2013 . The New York State audit of the Company's 2011-2014 tax years was finalized in 2016, resulting in an additional tax liability of $ 444,000 . The IRS audit of the 2013 tax year of LNB was concluded in 2016 and resulted in no additional tax liability.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2016
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Retained earnings are partially restricted in connection with regulations related to the insurance of deposit accounts, which requires Northwest to maintain certain statutory reserves. Northwest may not pay dividends on or repurchase any of its common stock if the effect thereof would reduce retained earnings below the level of adequate capitalization as defined by federal and state regulators. In tax years prior to fiscal 1997, Northwest was permitted, under the Internal Revenue Code ("IRC"), to deduct an annual addition to a reserve for bad debts in determining taxable income, subject to certain limitations. Bad debt deductions for income tax purposes are included in taxable income of later years only if the bad debt reserve is used subsequently for purposes other than to absorb bad debt losses. Because Northwest does not intend to use the reserve for purposes other than to absorb losses, no deferred income taxes have been provided prior to fiscal 1987. Retained earnings at December 31, 2016 and 2015 include approximately $39.1 million representing such bad debt deductions for which no deferred income taxes have been provided.

Earnings Per Share

Earnings Per Share	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share	Earnings Per Share Basic earnings per common share ("EPS") is computed by dividing net income available to common shareholders by the weighted average number of common shares outstanding for the period, without considering any dilutive items. Diluted EPS reflects the potential dilution that could occur if securities or other contracts to issue common stock were exercised or converted into common stock or resulted in the issuance of common stock that then shared in our earnings. All stock options outstanding during the year ended December 31, 2016 were included in the computation of diluted earnings per share because the stock options exercise price was less than the average market price of the common shares of $14.79 . For the year ended December 31, 2015 there were 524,250 options outstanding with a weighted average exercise price of $13.15 per share that were excluded in the computation of diluted earnings per share because the stock options’ exercise price was greater than the average market price of the common shares of $12.64 . All stock options outstanding during the year ended December 31, 2014 were included in the computation of diluted earnings per share because the stock options exercise price was less than the average market price of the common shares of $13.34 . The computation of basic and diluted earnings per share for the years ended December 31, 2016 , 2015 and 2014 follows: Years ended December 31, 2016 2015 2014 Net income available to common shareholders $ 49,667 60,540 61,962 Weighted average common shares outstanding 99,439,174 94,314,420 91,535,298 Dilutive potential shares due to effect of stock options 1,225,514 515,369 739,699 Total weighted average common shares and dilutive potential shares 100,664,688 94,829,789 92,274,997 Basic earnings per share (1) $ 0.50 0.64 0.68 Diluted earnings per share (1) $ 0.49 0.64 0.67 (1) Not in thousands.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2016
Compensation and Retirement Disclosure [Abstract]
Employee Benefit Plans	Employee Benefit Plans (a) Pension Plans We maintain noncontributory defined benefit pension plans covering substantially all employees and members of our board of directors. Retirement benefits are based on certain compensation levels, age, and length of service. Contributions are based on an actuarially determined amount to fund not only benefits attributed to service to date but also for those expected to be earned in the future. In addition, we have an unfunded Supplemental Executive Retirement Plan (“SERP”) to compensate those executive participants eligible for the defined benefit pension plan whose benefits are limited by Section 415 of the IRC. We also sponsor a retirement savings plan in which substantially all employees participate. We provide a matching contribution of 50% of each employee’s contribution to a maximum of 6% of the employee’s compensation. Total expense for all retirement plans, including defined benefit pension plans, was approximately $5.8 million , $4.6 million and $1.0 million , for the years ended December 31, 2016 , 2015 and 2014 , respectively. Components of net periodic pension cost and other amounts recognized in other comprehensive income: The following table sets forth the net periodic pension cost for the defined benefit pension plans for the years ended December 31, 2016 , 2015 and 2014 : Years ended December 31, 2016 2015 2014 Service cost $ 5,496 5,721 4,138 Interest cost 6,781 6,125 5,827 Expected return on plan assets (9,897 ) (10,371 ) (9,663 ) Net amortization and deferral 1,388 1,375 (897 ) Net periodic pension (benefit)/ cost $ 3,768 2,850 (595 ) The following table sets forth other changes in the defined benefit pension plans’ plan assets and benefit obligations recognized in other comprehensive income: Years ended December 31, 2016 2015 2014 Net loss/ (gain) $ 1,550 (420 ) 30,779 Prior service cost/ (credit) — — — Amortization of prior service cost 2,323 2,323 2,322 Total recognized in other comprehensive income $ 3,873 1,903 33,101 Total recognized in net periodic pension cost and other comprehensive income/ (loss) $ 7,641 4,753 32,506 The estimated net loss and prior service credit for the defined benefit pension plan that will be amortized from accumulated other comprehensive income into net periodic cost over the next year is $3.6 million and $(2.3) million , respectively. The following table sets forth information for the defined benefit pension plans’ funded status at December 31, 2016 and 2015 : December 31, 2016 2015 Change in benefit obligation: Benefit obligation at beginning of year $ 162,133 159,587 Service cost 5,496 5,721 Interest cost 6,781 6,125 Acquisition — 5,662 Actuarial (gain)/ loss 4,267 (9,357 ) Benefits paid (6,469 ) (5,605 ) Benefit obligation at end of year $ 172,208 162,133 Change in plan assets: Fair value of plan assets at beginning of year 143,655 140,183 Actual return on plan assets 8,903 (2,264 ) Employer contributions 6,536 6,460 Acquisition — 4,881 Benefits paid (6,469 ) (5,605 ) Fair value of plan assets at end of period $ 152,625 143,655 Funded status at end of year $ (19,583 ) (18,478 ) The following table sets forth the assumptions used to develop the net periodic pension cost: Years ended December 31, 2016 2015 2014 Discount rate 4.25 % 3.89 % 4.86 % Expected long-term rate of return on assets 7.00 % 7.50 % 7.50 % Rate of increase in compensation levels 3.00 % 3.00 % 3.00 % The following table sets forth the assumptions used to determine benefit obligations at the end of each period: Years ended December 31, 2016 2015 2014 Discount rate 4.06 % 4.25 % 3.89 % Expected long-term rate of return on assets 7.00 % 7.00 % 7.50 % Rate of increase in compensation levels 3.00 % 3.00 % 3.00 % The expected long-term rate of return on assets is based on the expected return of each of the asset categories, weighted based on the median of the target allocation for each category. We use the Citigroup Pension Liability Index rates matching the duration of our benefit payments as of the measurement date to determine the discount rate. The accumulated benefit obligation for the funded defined benefit pension plan was $165.9 million , $155.9 million and $153.9 million at December 31, 2016 , 2015 and 2014 , respectively. The accumulated benefit obligation for all unfunded defined benefit plans was $6.3 million , $6.3 million and $5.6 million at December 31, 2016 , 2015 and 2014 , respectively. The following table sets forth certain information related to our pension plans: December 31, 2016 2015 Projected benefit obligation $ 172,208 162,133 Accumulated benefit obligation 172,208 162,133 Fair value of plan assets 152,625 143,655 We anticipate making a contribution to our defined benefit pension plan of $4.0 million to $8.0 million during the year ending December 31, 2017 . The investment policy as established by the Plan Administrative Committee, to be followed by the Trustee, is to invest assets based on the target allocations shown in the table below. To meet target allocation ranges set forth by the Plan Administrative Committee, periodically, the assets are reallocated by the Trustee. The investment policy is reviewed periodically to determine if the policy should be changed. Pension assets are conservatively invested with the goal of providing market or better returns with below market risks. Assets are invested in a balanced portfolio composed primarily of equities, fixed income, and cash or cash equivalent investments. The Trustee tries to maintain an approximate asset mix position of 30% to 60% equities and 20% to 50% bonds. A maximum of 10% may be invested in any one stock, including the stock of Northwest Bancshares, Inc. The objective of holding equity securities is to provide capital appreciation consistent with the ownership of the common stocks of medium to large companies. Acceptable bond investments are direct or agency obligations of the U.S. Government or investment grade corporate bonds. The average maturity of the bond portfolio shall not exceed 10 years . The following table sets forth the weighted average asset allocation of defined benefit plans: Target December 31, Allocation 2016 2015 Debt securities 20 – 50% 23 % 20 % Equity securities 30 – 60% 72 % 69 % Other 5 – 50% 5 % 11 % Total 100 % 100 % All of the assets held by the defined benefit pension plan are measured and recorded at estimated fair value on our balance sheet on a recurring basis as Level 1 assets, as defined by the fair value hierarchy defined in note 16. The following table sets forth the pension plan assets as of December 31, 2016 and 2015 : December 31, 2016 2015 Mutual funds — debt $ 35,224 28,316 Mutual funds — equity 110,078 98,517 Cash and cash equivalents 7,322 16,822 The benefits expected to be paid in each year from 2017 to 2021 are $5.4 million , $5.7 million , $6.4 million , $6.6 million and $6.9 million , respectively. The aggregate benefits expected to be paid in the five years from 2021 to 2025 are $34.9 million . The expected benefits to be paid are based on the same assumptions used to measure our benefit obligations at December 31, 2016 and include estimated future employee service. (b) Postretirement Healthcare Plan In addition to pension benefits, we provide postretirement healthcare benefits for certain employees who were employed as of October 1, 1993 and were at least 55 years of age on that date. We use the accrual method of accounting for postretirement benefits other than pensions. Components of net periodic benefit cost and other amounts recognized in other comprehensive income: The following table sets forth the net periodic benefit cost for the postretirement healthcare benefits plan for the years ended December 31, 2016 , 2015 and 2014 : Years ended December 31, 2016 2015 2014 Service cost $ — — — Interest cost 70 58 65 Amortization of net loss 90 60 48 Net period benefit cost $ 160 118 113 The following table sets forth other changes in the postretirement healthcare plan’s plan assets and benefit obligations recognized in other comprehensive income: Years ended December 31, 2016 2015 2014 Net loss/ (gain) $ 109 273 195 Total recognized in other comprehensive income $ 109 273 195 Total recognized in net periodic benefit cost and other comprehensive income $ 270 391 308 The estimated net loss for the postretirement healthcare benefit plan that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year is $108,000 . The following table sets forth the funded status of the postretirement healthcare benefit plan at December 31, 2016 and 2015 : December 31, 2016 2015 Change in benefit obligation: Benefit obligation at beginning of year $ 1,737 1,565 Service cost — — Interest cost 70 58 Actuarial loss 200 333 Benefits paid (228 ) (219 ) Benefit obligation at end of year $ 1,779 1,737 Change in plan assets: Fair value of plan assets at beginning of year — — Employer contributions 228 219 Benefits paid (228 ) (219 ) Fair value of plan assets at end of year $ — — Funded status at year end $ (1,779 ) (1,737 ) The assumptions used to develop the preceding information for postretirement healthcare benefits are as follows: Years ended December 31, 2016 2015 2014 Discount rate 4.25 % 3.89 % 4.86 % Monthly cost of healthcare insurance per beneficiary (1) $ 539 470 384 Annual rate of increase in healthcare costs 4.00 % 4.00 % 4.00 % (1) Not in thousands If the assumed rate of increase in healthcare costs was increased by one percentage point to 5% from the level presented above, the interest cost component of net periodic postretirement healthcare benefit cost would increase by $11,000 and the accumulated postretirement benefit obligation for healthcare benefits would increase by $68,000 . The following table sets forth information for plans with an accumulated benefit obligation in excess of plan assets: December 31, 2016 2015 Projected benefit obligation $ 1,779 1,737 Accumulated benefit obligation 1,779 1,737 Fair value of plan assets — — (c) Employee Stock Ownership Plan On September 30, 2016, the Northwest Savings Bank Employee Stock Ownership Plan ("ESOP") was terminated. As a result, 1,366,574 unallocated ESOP shares were retired to satisfy the ESOP loan due to the Company. The remaining 401,356 unallocated ESOP shares were allocated to plan participants, the ESOP was then merged into the Northwest Savings Bank 401(k) Plan. ESOP compensation expense was $6.3 million , $335,000 and $3.0 million for the years ended December 31, 2016 , 2015 and 2014 , respectively. Compensation expense related to the ESOP is recognized at an amount equal to the number of common shares committed to be released by the ESOP to participants’ accounts multiplied by the average fair value of the common stock during the reporting period. The difference between the fair value of the shares of the common stock committed to be allocated by the ESOP to participants’ accounts for the period and the average cost of those common shares is recorded as an adjustment to either additional paid-in capital or retained earnings. (d) Common Stock Awards On April 20, 2011, we established the Northwest Bancshares, Inc. 2011 Equity Incentive Plan with 2,806,233 common shares authorized. On May 21, 2014, we awarded employees 251,030 common shares and outside directors 21,600 common shares with a grant date fair value of $13.22 per share (total market value of $3.6 million at issuance). On May 20, 2015, we awarded employees 282,050 common shares and outside directors 24,300 common shares with a grant date fair value of $12.31 per share (total market value of $3.8 million at issuance). On May 18, 2016, we awarded employees 310,160 common shares and outside directors 24,300 common shares with a grant date fair value of $14.51 per share (total market value of $4.9 million at issuance). Total common shares forfeited from the 2011 plan were 309,554 , of which, 49,776 shares were forfeited during the year ended December 31, 2016 . Forfeited shares may be awarded to other eligible recipients in future grants until the plan termination date in 2021. Common shares vest over a 10 -year period with the first vesting occurring on the grant date. As of December 31, 2016 , 30% of the 2014 issuances have vested, 20% of the 2015 issuances have vested and 10% of the 2016 issuances have vested. Once shares have vested, they are no longer restricted. Compensation expense, in the amount of the fair market value of the common stock at the date of the grant, will be recognized pro rata over the periods in which the shares vest. While restricted, the recipients are entitled to all shareholder rights, except that the shares may not be sold, pledged, or otherwise disposed of and are required to be held in a trust. (e) Stock Option Plans On April 20, 2011, we established the Northwest Bancshares, Inc. 2011 Equity Incentive Plan, which authorizes the granting of 7,015,583 stock options. On May 21, 2014, we granted employees 534,950 stock options and outside directors 57,600 stock options with an exercise price of $13.15 per share. On May 19, 2015, we granted employees 660,570 stock options and outside directors 64,800 stock options with an exercise price of $12.37 per share. On May 17, 2016, we granted employees 660,600 stock options and outside directors 64,800 stock options with an exercise price of $14.15 per share. Awarded stock options vest over a ten -year period with the first vesting occurring on the grant date with a ten year exercise period from the grant date. The following table summarizes the activity in our option plans during the years ended December 31, 2016 , 2015 and 2014 (amounts in this table are not in thousands): Years ended December 31, 2016 2015 2014 Number Weighted average exercise price Number Weighted average exercise price Number Weighted average exercise price Balance at beginning of year 6,306,496 $ 11.81 6,402,407 $ 11.65 6,816,294 $ 11.46 Granted (1) 725,400 14.15 665,370 12.37 592,550 13.15 Exercised (2) (1,081,072 ) 11.01 (474,253 ) 10.27 (745,419 ) 10.86 Forfeited/ expired (146,719 ) 12.71 (287,028 ) 12.26 (261,018 ) 11.71 Balance at end of year 5,804,105 $ 12.25 6,306,496 $ 11.81 6,402,407 $ 11.65 Exercisable at end of year 3,035,718 $ 11.71 3,431,113 $ 11.42 3,333,942 $ 11.20 (1) Weighted average fair value of options at grant date: $1.52 , $1.14 and $1.45 , respectively. (2) The total intrinsic value of options exercised was $5.1 million , $1.2 million and $2.3 million , respectively. The aggregate intrinsic value of all options expected to vest and fully vested options at December 31, 2016 is $14.4 million and $19.2 million , respectively. The following table summarizes the number of options outstanding, number of options exercisable, and weighted average remaining life of all option grants as of December 31, 2016 : Exercise Exercise Exercise Exercise Exercise Exercise Exercise Options outstanding: Number of options 195,902 207,156 125,448 320,045 47,557 432,941 398,478 Weighted average remaining contract life (years) 2.25 2.00 1.25 3.25 0.25 5.50 4.25 Options exercisable: Number of options 195,902 207,156 125,448 298,473 47,557 226,915 309,987 Weighted average remaining term - vested (years) 2.25 2.00 1.25 3.25 0.25 5.50 4.25 Exercise Exercise Exercise Exercise Exercise Exercise Total Options outstanding: Number of options 21,500 1,815,615 577,405 474,467 487,865 699,726 5,804,105 Weighted average remaining contract life (years) 4.50 4.50 8.50 6.50 7.50 9.50 5.59 Options exercisable: Number of options 12,931 1,151,004 81,759 199,534 132,186 46,866 3,035,718 Weighted average remaining term - vested (years) 4.50 4.50 8.50 6.50 7.50 9.50 4.05

Disclosures About Fair Value of

Disclosures About Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Disclosures About Fair Value of Financial Instruments	Disclosures About Fair Value of Financial Instruments We are required to disclose fair value information about financial instruments whether or not recognized in the consolidated statement of financial condition. Fair value information of certain financial instruments and all nonfinancial instruments is not required to be disclosed. Accordingly, the aggregate fair value amounts presented do not represent the underlying value of the Company. Financial assets and liabilities recognized or disclosed at fair value on a recurring basis and certain financial assets and liabilities on a non-recurring basis are accounted for using a three-level hierarchy of valuation techniques based on whether the inputs to those valuation techniques are observable or unobservable. This hierarchy gives the highest priority to quoted prices with readily available independent data in active markets for identical assets or liabilities (Level 1) and the lowest priority to unobservable market inputs (Level 3). When various inputs for measurement fall within different levels of the fair value hierarchy, the lowest level input that has a significant impact on fair value measurement is used. Financial assets and liabilities are categorized based upon the following characteristics or inputs to the valuation techniques: • Level 1 — Financial assets and liabilities for which inputs are observable and are obtained from reliable quoted prices for identical assets or liabilities in actively traded markets. This is the most reliable fair value measurement and includes, for example, active exchange-traded equity securities. • Level 2 — Financial assets and liabilities for which values are based on quoted prices in markets that are not active or for which values are based on similar assets or liabilities that are actively traded. Level 2 also includes pricing models in which the inputs are corroborated by market data, for example, matrix pricing. • Level 3 — Financial assets and liabilities for which values are based on prices or valuation techniques that require inputs that are both unobservable and significant to the overall fair value measurement. Level 3 inputs include the following: • Quotes from brokers or other external sources that are not considered binding; • Quotes from brokers or other external sources where it cannot be determined that market participants would in fact transact for the asset or liability at the quoted price; • Quotes and other information from brokers or other external sources where the inputs are not deemed observable. We are responsible for the valuation process and as part of this process may use data from outside sources in establishing fair value. We perform due diligence to understand the inputs used or how the data was calculated or derived. We also corroborate the reasonableness of external inputs in the valuation process. The carrying amounts reported in the consolidated statement of financial condition approximate fair value for the following financial instruments: cash on hand, interest-earning deposits in other institutions, federal funds sold and other short-term investments, accrued interest receivable, accrued interest payable, and marketable securities available-for-sale. Marketable Securities Where available, market values are based on quoted market prices, dealer quotes, and prices obtained from independent pricing services. Debt securities — available for sale - Generally, debt securities are valued using pricing for similar securities, recently executed transactions and other pricing models utilizing observable inputs. The valuation for most debt securities is classified as Level 2. Securities within Level 2 include corporate bonds, municipal bonds, mortgage-backed securities and US government obligations. Certain debt securities which were AAA rated at purchase do not have an active market and as such we have used an alternative method to determine the fair value of these securities. The fair value has been determined using a discounted cash flow model using market assumptions, which generally include cash flow, collateral and other market assumptions. As such, securities which otherwise would have been classified as level 2 securities if an active market for those assets or similar assets existed are included herein as level 3 assets. Other debt securities, pooled trust preferred securities rated below AA at purchase, have a fair value based on a discounted cash flow model using similar assumptions to those noted above and accordingly are classified as level 3 assets. Equity securities — available for sale - Level 1 securities include publicly traded securities valued using quoted market prices. We consider the financial condition of the issuer to determine if the securities have indicators of impairment. Debt securities — held to maturity — The fair value of debt securities held to maturity is determined in the same manner as debt securities available for sale. Loans Receivable Loans with comparable characteristics including collateral and re-pricing structures are segregated for valuation purposes. Each loan pool is separately valued utilizing a discounted cash flow analysis. Projected monthly cash flows are discounted to present value using a market rate for comparable loans, which is not considered an exit price. Characteristics of comparable loans include remaining term, coupon interest, and estimated prepayment speeds. Delinquent loans are separately evaluated given the impact delinquency has on the projected future cash flow of the loan including the approximate discount or market rate, which is not considered an exit price. FHLB Stock Due to the restrictions placed on the transferability of FHLB stock it is not practical to determine the fair value. Deposit Liabilities The estimated fair value of deposits with no stated maturity, which includes demand deposits, money market, and other savings accounts, is the amount payable on demand. Although market premiums paid for depository institutions reflect an additional value for these low-cost deposits, adjusting fair value for any value expected to be derived from retaining those deposits for a future period of time or from the benefit that results from the ability to fund interest-earning assets with these deposit liabilities is prohibited. The fair value estimates of deposit liabilities do not include the benefit that results from the low-cost funding provided by these deposits compared to the cost of borrowing funds in the market. Fair values for time deposits are estimated using a discounted cash flow calculation that applies contractual cost currently being offered in the existing portfolio to current market rates being offered locally for deposits of similar remaining maturities. The valuation adjustment for the portfolio consists of the present value of the difference of these two cash flows, discounted at the assumed market rate of the corresponding maturity. Borrowed Funds Fixed rate advances are valued by comparing their contractual cost to the prevailing market cost. The carrying amount of repurchase agreements approximates fair value. Junior Subordinated Debentures The fair value of junior subordinated debentures is calculated using the discounted cash flows at the prevailing rate of interest. Cash flow hedges — Interest rate swap agreements (“swaps”) The fair value of the swaps is the amount we would have expected to pay to terminate the agreements and is based upon the present value of the expected future cash flows using the LIBOR swap curve, the basis for the underlying interest rate. Off-Balance Sheet Financial Instruments These financial instruments generally are not sold or traded, and estimated fair values are not readily available. However, the fair value of commitments to extend credit and standby letters of credit is estimated using the fees currently charged to enter into similar agreements. Commitments to extend credit are generally short-term in nature and, if drawn upon, are issued under current market terms. At December 31, 2016 and 2015 , there was no significant unrealized appreciation or depreciation on these financial instruments. The following table sets forth the carrying amount and estimated fair value of our financial instruments included in the consolidated statement of financial condition at December 31, 2016 and 2015 : December 31, 2016 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 389,867 389,867 389,867 — — Securities available-for-sale 826,200 826,200 4,440 812,394 9,366 Securities held-to-maturity 19,978 20,426 — 20,426 — Loans receivable, net 7,496,408 7,878,815 9,625 — 7,869,190 Accrued interest receivable 21,699 21,699 21,699 — — FHLB Stock 7,390 7,390 — — — Total financial assets $ 8,761,542 9,144,397 425,631 832,820 7,878,556 Financial liabilities: Savings and checking accounts $ 6,341,735 6,341,735 6,341,735 — — Time deposits 1,540,586 1,626,434 — — 1,626,434 Borrowed funds 142,899 142,899 142,899 — — Junior subordinated debentures 111,213 113,313 — — 113,313 Cash flow hedges - swaps 2,736 2,736 — 2,736 — Accrued interest payable 643 643 643 — — Total financial liabilities $ 8,139,812 8,227,760 6,485,277 2,736 1,739,747 December 31, 2015 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 167,408 167,408 167,408 — — Securities available-for-sale 874,405 874,405 1,894 863,556 8,955 Securities held-to-maturity 31,689 32,552 — 32,552 — Loans receivable, net 7,159,449 7,482,431 — — 7,482,431 Accrued interest receivable 21,072 21,072 21,072 — — FHLB Stock 40,903 40,903 — — — Total financial assets $ 8,294,926 8,618,771 190,374 896,108 7,491,386 Financial liabilities: Savings and checking accounts $ 4,917,863 4,917,863 4,917,863 — — Time deposits 1,694,718 1,710,388 — — 1,710,388 Borrowed funds 975,007 998,527 118,664 — 879,863 Junior subordinated debentures 111,213 115,268 — — 115,268 Cash flow hedges - swaps 4,276 4,276 — 4,276 — Accrued interest payable 1,993 1,993 1,993 — — Total financial liabilities $ 7,705,070 7,748,315 5,038,520 4,276 2,705,519 Fair value estimates are made at a point-in-time, based on relevant market data and information about the instrument. The preceding methods and assumptions were used in estimating the fair value of financial instruments at December 31, 2016 and 2015 . There were no transfers of financial instruments between Level 1 and Level 2 during the years ended December 31, 2016 and 2015 . The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 : Level 1 Level 2 Level 3 Total at fair value Equity securities $ 4,440 — — 4,440 Debt securities: U.S. government and agencies — 6 — 6 Government sponsored enterprises — 294,170 — 294,170 States and political subdivisions — 63,070 — 63,070 Corporate — 7,614 9,366 16,980 Total debt securities — 364,860 9,366 374,226 Residential mortgage-backed securities: GNMA — 30,883 — 30,883 FNMA — 106,578 — 106,578 FHLMC — 82,115 — 82,115 Non-agency — 579 — 579 Collateralized mortgage obligations: GNMA — 6,287 — 6,287 FNMA — 95,186 — 95,186 FHLMC — 119,197 — 119,197 SBA — 6,608 — 6,608 Non-agency — 101 — 101 Total mortgage-backed securities — 447,534 — 447,534 Interest rate swaps — (2,736 ) — (2,736 ) Total assets and liabilities $ 4,440 809,658 9,366 823,464 The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2015 : Level 1 Level 2 Level 3 Total at fair value Equity securities $ 1,894 — — 1,894 Debt securities: U.S. government and agencies — 11 — 11 Government sponsored enterprises — 294,440 — 294,440 States and political subdivisions — 82,868 — 82,868 Corporate — 7,520 8,955 16,475 Total debt securities — 384,839 8,955 393,794 Residential mortgage-backed securities: GNMA — 27,082 — 27,082 FNMA — 99,170 — 99,170 FHLMC — 50,369 — 50,369 Non-agency — 606 — 606 Collateralized mortgage obligations: GNMA — 10,669 — 10,669 FNMA — 122,528 — 122,528 FHLMC — 157,378 — 157,378 SBA — 8,166 — 8,166 Non-agency — 2,749 — 2,749 Total mortgage-backed securities — 478,717 — 478,717 Interest rate swaps — (4,276 ) — (4,276 ) Total assets and liabilities $ 1,894 859,280 8,955 870,129 The table below presents a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the year ended December 31, 2016 and 2015 : December 31, 2016 2015 Debt securities Beginning balance January 1, $ 8,955 10,597 Total net realized investment gains/ (losses) and net change in unrealized appreciation/ (depreciation): Included in net income as OTTI — — Included in other comprehensive income 411 (502 ) Purchases — — Sales/ calls — (1,140 ) Transfers into Level 3 — — Transfers out of Level 3 — — Ending balance December 31, $ 9,366 8,955 Certain assets and liabilities are measured at fair value on a nonrecurring basis after initial recognition such as loans held for sale, loans measured for impairment, real estate owned, and mortgage servicing rights. The following table represents the fair market measurement for only those nonrecurring assets that had a fair market value below the carrying amount as of December 31, 2016 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 41,933 41,933 Mortgage servicing rights — — 246 246 Real estate owned — — 4,889 4,889 Total assets $ — — 47,068 47,068 The following table represents the fair market measurement for only those nonrecurring assets that had a fair market value below the carrying amount as of December 31, 2015 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 48,181 48,181 Real estate owned — — 8,725 8,725 Total assets $ — — 56,906 56,906 Loans measured for impairment - A loan is considered to be impaired as described in note 1 (f). We classify impaired loans as nonrecurring Level 3. Mortgage servicing rights - Mortgage servicing rights represent the value of servicing residential mortgage loans, when the mortgage loans have been sold into the secondary market and the associated servicing has been retained. The value is determined through a discounted cash flow analysis, which uses interest rates, prepayment speeds and delinquency rate assumptions as inputs. All of these assumptions require a significant degree of management judgment. Servicing rights and the related mortgage loans are segregated into categories or homogeneous pools based upon common characteristics. Adjustments are only made when the estimated discounted future cash flows are less than the carrying value, as determined by individual pool. As such, mortgage servicing rights are classified as nonrecurring Level 3. Real estate owned - Real estate owned is comprised of property acquired through foreclosure or voluntarily conveyed by borrowers. These assets are recorded on the date acquired at the lower of the related loan balance or fair value, less estimated disposition costs, with the fair value being determined by appraisal. Subsequently, foreclosed assets are valued at the lower of the amount recorded at acquisition date or fair value, less estimated disposition costs. We classify real estate owned as nonrecurring Level 3. The following table presents additional quantitative information about assets measured at fair value on a recurring and nonrecurring basis and for which we have utilized Level 3 inputs to determine fair value at December 31, 2016 : Fair value Valuation techniques Significant unobservable inputs Range (weighted average) Debt securities $ 9,366 Discounted cash Discount margin 0.4% to 2.1% (0.7)% flow Default rates 1.00% Prepayment speeds 1.00% annually Loans measured for impairment 41,933 Appraisal Estimated costs to sell 10% value (1) Discounted cash Discount rate 3.8% to 20.0% (11.0%) flow Mortgage servicing rights 246 Discounted cash Annual service cost 80 flow Prepayment rate 6.0% to 7.4% (7.1%) Expected life (months) 66.2 to 70.9 (68.9) Option adjusted spread 800 basis points Forward yield curve 0.6% to 2.2% (1.3%) Real estate owned 4,889 Appraisal Estimated costs to sell 10% value (1) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which may include Level 3 inputs that are not identifiable, or by using the discounted cash flow method if the loan is not collateral dependent. The significant unobservable inputs used in the fair value measurement of our debt securities are discount margins, default rates and prepayment speeds. Significant increases in any of those rates would result in a significantly lower fair value measurement.

Regulatory Capital Requirements

Regulatory Capital Requirements	12 Months Ended
	Dec. 31, 2016
Regulatory Capital Requirements [Abstract]
Regulatory Capital Requirements	Regulatory Capital Requirements We and our banking subsidiary are subject to various regulatory capital requirements administered by the federal and state banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory, and possibly additional discretionary actions by the regulators that, if undertaken, could have a direct material effect on our financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, specific capital guidelines that involve quantitative measures of assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices must be met. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. In July 2013, the FDIC and the other federal regulatory agencies issued a final rule that revised their leverage and risk-based capital requirements and the method for calculating risk-weighted assets to make them consistent with agreements that were reached by the Basel Committee on Banking Supervision and certain provisions of the Dodd-Frank Act. Among other things, the rule establishes a new Common Equity Tier I (“CET1”) minimum capital requirement (4.5% of risk-weighted assets) and increases the minimum Tier 1 capital to risk-based assets requirement (from 4% to 6% of risk-weighted assets). The rule limits an organization's capital distributions and certain discretionary bonus payments if the organization does not hold a "capital conservation buffer" consisting of 2.5% of CET1 capital to risk-weighted assets in addition to the amount necessary to meet its minimum risk-based capital requirements. The final rule became effective for Northwest on January 1, 2015. The capital conservation buffer requirement will be phased in beginning January 1, 2016 and ending January 1, 2019, when the full capital conservation buffer requirement will be effective. Quantitative measures established by regulation to ensure capital adequacy require us and our banking subsidiary to maintain minimum amounts and ratios (set forth in the table below) of total, Tier 1, and CET1 capital (as defined in the regulations) to risk-weighted assets (as defined) and of Tier I capital to average assets (as defined). As of December 31, 2016 and 2015 , we and our banking subsidiary exceeded all capital adequacy requirements to which we were subject. As of December 15, 2016, the most recent notification from the FDIC categorized Northwest Bank as “well capitalized” under the regulatory framework for prompt corrective action. To be categorized as “well capitalized,” the bank must maintain total risk-based, Tier 1 risk-based, CET 1 risk-based, and Tier 1 leverage ratios as set forth in the table. There are no conditions or events since that notification that management believes have changed the bank’s categories. The actual, required, and well capitalized levels as of December 31, 2016 and 2015 were as follows: At December 31, 2016 Minimum capital Well capitalized Actual requirements (1) requirements (1) Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,051,582 14.873 % 609,835 8.625 % 751,246 10.625 % Northwest Bank 961,279 13.609 % 609,248 8.625 % 750,523 10.625 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 990,153 14.004 % 468,424 6.625 % 609,835 8.625 % Northwest Bank 900,328 12.746 % 467,973 6.625 % 609,248 8.625 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 882,278 12.478 % 362,366 5.125 % 503,777 7.125 % Northwest Bank 900,328 12.746 % 362,017 5.125 % 503,292 7.125 % Tier 1 capital (leverage) (to average assets) Northwest Bancshares, Inc. 990,153 10.530 % 376,116 4.000 % 470,145 5.000 % Northwest Bank 900,328 9.585 % 375,735 4.000 % 469,669 5.000 % (1) Amounts and ratios include the 2016 capital conservation buffer of 0.625% with the exception of Tier 1 capital to average assets. At December 31, 2015 Minimum capital Well capitalized Actual requirements requirements (1) Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,102,468 16.63 % 530,257 8.00 % 662,821 10.00 % Northwest Bank 1,006,230 15.20 % 529,498 8.00 % 661,872 10.00 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,039,574 15.68 % 397,693 6.00 % 530,257 8.00 % Northwest Bank 943,554 14.26 % 397,123 6.00 % 529,498 8.00 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 931,699 14.06 % 298,269 4.50 % 430,834 6.50 % Northwest Bank 943,554 14.26 % 297,843 4.50 % 430,217 6.50 % Tier I capital (leverage) (to average assets) Northwest Bancshares, Inc. 1,039,574 11.96 % 347,582 4.00 % 434,477 5.00 % Northwest Bank 943,554 10.87 % 347,063 4.00 % 433,829 5.00 %

Contingent Liabilities

Contingent Liabilities	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Contingent Liabilities	Contingent Liabilities We and our subsidiaries are subject to a number of asserted and unasserted claims encountered in the normal course of business. Management believes that the aggregate liability, if any, that may result from such potential litigation will not have a material adverse effect on our financial statements. However, we cannot presently determine whether or not any claims against us will have a material adverse effect on our results of operations in any future reporting period.

Legal Proceedings

Legal Proceedings	12 Months Ended
	Dec. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
Legal Proceedings	Legal Proceedings We establish accruals for legal proceedings when information related to the loss contingencies represented by those matters indicates both that a loss is probable and that the amount of loss can be reasonably estimated. As of December 31, 2016 we have not accrued for legal proceedings based on our analysis of currently available information. These accruals, if any, are subject to significant judgment and a variety of assumptions and uncertainties. Any such accruals are adjusted thereafter as appropriate to reflect changes in circumstances. Due to the inherent subjectivity of assessments and unpredictability of outcomes of legal proceedings, any amounts accrued may not represent the ultimate loss to us from legal proceedings.

Components of Accumulated Other

Components of Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Components of Accumulated Other Comprehensive Income	Components of Accumulated Other Comprehensive Income The following table sets forth the components of accumulated other comprehensive income as of December 31, 2016 and 2015 : December 31, 2016 2015 Unrealized gain on marketable securities available-for-sale $ 395 3,325 Fair value of interest rate swaps (1,778 ) (2,779 ) Defined benefit pension plans (26,608 ) (25,081 ) Accumulated other comprehensive income $ (27,991 ) (24,535 ) The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2016 : Unrealized gains and losses on securities available-for- sale Change in fair value of interest rate swaps Change in defined benefit pension plans Total Balance as of January 1, $ 3,325 (2,779 ) (25,081 ) (24,535 ) Other comprehensive income/ (loss) before reclassification adjustments (2,728 ) 1,001 (2,399 ) (4,126 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (202 ) — 872 670 Net other comprehensive income/ (loss) (2,930 ) 1,001 (1,527 ) (3,456 ) Balance as of December 31, $ 395 (1,778 ) (26,608 ) (27,991 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $331 , net of tax (income tax expense) of $(129) . (2) Consists of amortization of prior service cost (compensation and employee benefits) of $2,323 and amortization of net loss (compensation and employee benefits) of $(3,801) , net of tax (income tax expense) of $606 . See note 15. The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2015 : Unrealized gains and losses on securities available-for- sale Change in fair value of interest rate swaps Change in defined benefit pension plans Total Balance as of January 1, $ 3,461 (4,078 ) (23,753 ) (24,370 ) Other comprehensive income/ (loss) before reclassification adjustments 315 1,299 (2,203 ) (589 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (451 ) — 875 424 Net other comprehensive income/ (loss) (136 ) 1,299 (1,328 ) (165 ) Balance as of December 31, $ 3,325 (2,779 ) (25,081 ) (24,535 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $740 net of tax (income tax expense) of $(289) . (2) Consists of amortization of prior service cost (compensation and employee benefits) of $2,323 and amortization of net loss (compensation and employee benefits) of $(3,758) , net of tax (income tax expense) of $560 . See note 15. The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2014 : Unrealized gains and losses on securities available-for- sale Change in fair value of interest rate swaps Change in defined benefit pension plans Total Balance as of January 1, $ (3,233 ) (5,224 ) (3,443 ) (11,900 ) Other comprehensive income/ (loss) before reclassification adjustments 9,042 1,146 (19,758 ) (9,604 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (2,348 ) — (552 ) (2,866 ) Net other comprehensive income/ (loss) 6,694 1,146 (20,310 ) (12,470 ) Balance as of December 31, $ 3,461 (4,078 ) (23,753 ) (24,370 ) (1) Consists of realized losses on securities (gain on sales of investments, net) of 3,849 net of tax (income tax expense) of $(1,501) . (2) Consists of amortization of prior service cost (compensation and employee benefits) of $2,323 and amortization of net loss (compensation and employee benefits) of $(1,436) , net of tax (income tax expense) of $(335) . See note 15.

Parent Company Only Financial S

Parent Company Only Financial Statements - Condensed	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Parent Company Only Financial Statements - Condensed	Parent Company Only Financial Statements - Condensed Statements of Financial Condition December 31, 2016 2015 Assets Cash and cash equivalents $ 34,521 91,056 Marketable securities available-for-sale 4,413 1,884 Investment in bank subsidiary 1,193,175 1,182,308 Other assets 52,645 3,547 Total assets $ 1,284,754 1,278,795 Liabilities and Shareholders’ Equity Liabilities: Debentures payable $ 111,213 111,213 Other liabilities 2,878 4,419 Total liabilities 114,091 115,632 Shareholders’ equity 1,170,663 1,163,163 Total liabilities and shareholders’ equity $ 1,284,754 1,278,795 Statements of Income Years ended December 31, 2016 2015 2014 Income: Interest income $ 737 1,258 1,248 Other income 709 659 3,424 Dividends from bank subsidiary 50,000 135,000 66,183 Undistributed earnings from equity investment in bank subsidiary 2,760 (70,854 ) (3,261 ) Total income 54,206 66,063 67,594 Expense: Compensation and benefits 1,129 1,061 962 Other expense 561 1,356 572 Interest expense 4,560 4,926 4,691 Total expense 6,250 7,343 6,225 Income before income taxes 47,956 58,720 61,369 Federal and state income taxes (1,711 ) (1,820 ) (593 ) Net income $ 49,667 60,540 61,962 Statements of Cash Flows Years ended December 31, 2016 2015 2014 Operating activities: Net income $ 49,667 60,540 61,962 Adjustments to reconcile net income to net cash provided by operating activities: Undistributed earnings of subsidiary (2,760 ) 70,854 3,261 Noncash stock benefit plan compensation expense 10,916 5,654 5,714 Gain on sale of marketable securities (43 ) (54 ) (2,768 ) Net change in other assets and liabilities (63,533 ) (5,824 ) (2,352 ) Net cash provided by/ (used in) operating activities (5,753 ) 131,170 65,817 Investing activities: Net sale of marketable securities (1,952 ) 1,192 2,658 Acquisition, net of cash received — (89,398 ) — Net cash provided by/ (used in) investing activities (1,952 ) (88,206 ) 2,658 Financing activities: Cash dividends paid (60,156 ) (52,825 ) (149,932 ) Share repurchases (1,752 ) (7,847 ) (5,273 ) Repayment of loan to ESOP 797 1,549 1,190 Redemption of junior subordinated debt — (8,119 ) — Excess tax benefit from stock-based compensation 1,425 332 945 Proceeds from options exercised 10,856 4,303 6,519 Net cash used in financing activities (48,830 ) (62,607 ) (146,551 ) Net decrease in cash and cash equivalents $ (56,535 ) (19,643 ) (78,076 ) Cash and cash equivalents at beginning of year 91,056 110,699 188,775 Net decrease in cash and cash equivalents (56,535 ) (19,643 ) (78,076 ) Cash and cash equivalents at end of year $ 34,521 91,056 110,699

Business Segments

Business Segments	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Business Segments	Business Segments We have identified two reportable business segments based upon the operating approach currently used by management. The Community Banking segment includes our savings bank subsidiary, Northwest Bank, as well as the subsidiaries of the savings bank that provide similar products and services. The bank is a community-oriented institution that offers a full array of personal and business deposit and loan products, including mortgage, consumer, and commercial loans as well as trust, investment management, actuarial and benefit plan administration, and brokerage services typically offered by a full service financial institution. The Consumer Finance segment is comprised of Northwest Consumer Discount Company, a subsidiary of Northwest Bank. This subsidiary compliments the services of the bank by offering personal installment loans for a variety of consumer and real estate products. This activity is funded primarily through its intercompany borrowing relationship with Allegheny Services, Inc. Net income is primarily used by management to measure segment performance. The following tables provide financial information for these segments. The All Other column represents the parent company, other nonbank subsidiaries, and elimination entries necessary to reconcile to the consolidated amounts presented in the financial statements. At or for the year ended Community Banking Consumer Finance All Other (1) Consolidated External interest income $ 327,855 17,064 715 345,634 Intersegment interest income 2,564 — (2,564 ) — Interest expense 33,883 2,564 1,852 38,299 Provision for loan losses 9,846 3,696 — 13,542 Noninterest income 83,631 1,597 132 85,360 Noninterest expense 295,023 11,579 1,236 307,838 Income tax expense/ (benefit) 23,023 336 (1,711 ) 21,648 Net income $ 52,275 486 (3,094 ) 49,667 Total assets $ 9,500,419 109,744 13,477 9,623,640 At or for the year ended Community Banking Consumer Finance All Other (1) Consolidated External interest income $ 300,746 17,978 856 319,580 Intersegment interest income 2,393 — (2,393 ) — Interest expense 51,895 2,393 2,039 56,327 Provision for loan losses 7,429 2,283 — 9,712 Noninterest income 67,167 1,555 114 68,836 Noninterest expense 219,793 12,120 1,964 233,877 Income tax expense 28,642 1,138 (1,820 ) 27,960 Net income $ 62,547 1,599 (3,606 ) 60,540 Total assets $ 8,827,574 110,670 13,655 8,951,899 At or for the year ended Community Banking Consumer Finance All Other (1) Consolidated External interest income $ 285,635 18,789 1,003 305,427 Intersegment interest income 2,406 — (2,406 ) — Interest expense 52,291 2,406 1,890 56,587 Provision for loan losses 17,500 2,814 — 20,314 Noninterest income 66,431 1,517 2,818 70,766 Noninterest expense 202,489 11,968 1,078 215,535 Income tax expense/ (benefit) 21,097 1,291 (593 ) 21,795 Net income $ 61,095 1,827 (960 ) 61,962 Total assets $ 7,650,665 107,216 17,152 7,775,033 (1) Eliminations consist of intercompany interest income and interest expense.

Guaranteed Preferred Beneficial

Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements	12 Months Ended
	Dec. 31, 2016
Guaranteed Preferred Beneficial Interests in Company's Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements
Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements	Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements We have two legacy statutory business trusts: Northwest Bancorp Capital Trust III, a Delaware statutory business trust, and Northwest Bancorp Statutory Trust IV, a Connecticut statutory business trust (the Trusts). The trusts exist solely to issue preferred securities to third parties for cash, issue common securities to the Company in exchange for capitalization of the Trusts, invest the proceeds from the sale of trust securities in an equivalent amount of debentures of the Company, and engage in other activities that are incidental to those previously listed. The Trusts are not consolidated. Northwest Bancorp Capital Trust III issued 50,000 cumulative trust preferred securities in a private transaction to a pooled investment vehicle on December 5, 2005 (liquidation value of $1,000 per preferred security or $50,000,000 ) with a stated maturity of December 30, 2035 and a floating rate of interest, which is reset quarterly, equal to three-month LIBOR plus 1.38% . Northwest Bancorp Statutory Trust IV issued 50,000 cumulative trust preferred securities in a private transaction to a pooled investment vehicle on December 15, 2005 (liquidation value of $1,000 per preferred security or $50,000,000 ) with a stated maturity of December 15, 2035 and a floating rate of interest, which is reset quarterly, equal to three-month LIBOR plus 1.38% . As the shareholders of the trust preferred securities are the primary beneficiaries of the Trusts, the Trusts are not consolidated in our financial statements. The Trusts have invested the proceeds of the offerings in junior subordinated deferrable interest debentures issued by the Company. The structure of these debentures mirrors the structure of the trust-preferred securities. Northwest Bancorp Capital Trust III holds $51,547,000 of the Company’s junior subordinated debentures due December 30, 2035 with a floating rate of interest, reset quarterly, of three-month LIBOR plus 1.38% . The rate in effect at December 31, 2016 was 2.38% . Northwest Bancorp Statutory Trust IV holds $51,547,000 of the Company’s junior subordinated debentures due December 15, 2035 with a floating rate of interest, reset quarterly, of three-month LIBOR plus 1.38% . The rate in effect at December 31, 2016 was 2.34% . Cash distributions on the trust securities are made on a quarterly basis to the extent interest on the debentures is received by the Trusts. We have the right to defer payment of interest on the subordinated debentures at any time, or from time-to-time, for periods not exceeding 5 years . If interest payments on the subordinated debentures are deferred, the distributions on the trust securities also are deferred. To date there have been no interest deferrals. Interest on the subordinated debentures and distributions on the trust securities is cumulative. Our obligation constitutes a full, irrevocable, and unconditional guarantee on a subordinated basis of the obligations of the trust under the preferred securities. The Trusts must redeem the preferred securities when the debentures are paid at maturity or upon an earlier redemption of the debentures to the extent the debentures are redeemed. All or part of the debentures may be redeemed at any time. Also, the debentures may be redeemed at any time if existing laws or regulations, or the interpretation or application of these laws or regulations, change causing: • the interest on the debentures to no longer be deductible by the Company for federal income tax purposes; • the trust to become subject to federal income tax or to certain other taxes or governmental charges; • the trust to register as an investment company; or • the preferred securities do not qualify as Tier I capital. We may, at any time, dissolve any of the Trusts and distribute the debentures to the trust security holders, subject to receipt of any required regulatory approval(s). As a result of the LNB acquisition we acquired two statutory business trusts: LNB Trust I and LNB Trust II, both Delaware statutory business trusts. The outstanding stock issued by LNB Trust I was redeemed on December 15, 2015. At December 31, 2015, LNB Trust II had 7,875 cumulative trust preferred securities outstanding (liquidation value of $1,000 per preferred security or $7,875,000 ) with a stated maturity of June 15, 2037. These securities carry a fixed interest rate of 6.64% through June 15, 2017, then becomes a floating interest rate, which is reset quarterly, equal to three-month LIBOR plus 1.48% . LNB Trust II invested the proceeds of the offerings in junior subordinated deferrable interest debentures acquired by the Company. The structure of these debentures mirrors the structure of the trust-preferred securities. LNB Trust II holds $8,119,000 of junior subordinated debentures. These subordinated debentures are the sole assets of the Trust. Cash distributions on the trust securities are made on a quarterly basis to the extent interest on the debentures is received by the Trust. We are currently a counterparty to two interest rate swap agreements (swaps), designating the swaps as cash flow hedges. The swaps are intended to protect against the variability of cash flows associated with Northwest Bancorp Capital Trust III and Northwest Bancorp Capital Trust IV. The first swap modifies the re-pricing characteristics of Northwest Bancorp Capital Trust III, wherein for a 10 years period expiring in September 2018, the Company receives interest of three-month LIBOR from a counterparty and pays a fixed rate of 4.61% to the same counterparty calculated on a notional amount of $25.0 million . The second swap modifies the re-pricing characteristics of Northwest Bancorp Capital Trust IV, wherein for a ten year period expiring in December 2018, the Company receives interest of three-month LIBOR from a counterparty and pays a fixed rate of 4.09% to the same counterparty calculated on a notional amount of $25.0 million . The swap agreements were entered into with a counterparty that met our credit standards and the agreements contain collateral provisions protecting the at-risk party. We believe that the credit risk inherent in the contracts is not significant. At December 31, 2016 , $3.0 million of cash was pledged as collateral to the counterparty. At December 31, 2016 , the fair value of the swap agreements was $( 2.7 ) million and was the amount we would have expected to pay if the contracts were terminated. At December 31, 2016 , there was no material hedge ineffectiveness for any of the swaps discussed above. December 31, Liability Derivatives (Included in Other Liabilities) 2016 2015 Cash flow hedges — swaps: Fair value $ 2,736 4,276 Notional amount 50,000 50,000 Collateral posted 3,005 4,705 The following table sets forth a summary of guaranteed capital debt securities and junior subordinated deferrable interest debentures held by the trusts as of December 31, 2016 and 2015 : Capital Debt December 31, Securities 2016 2015 Northwest Bancorp Capital Trust III $ 50,000 51,547 51,547 Northwest Bancorp Statutory Trust IV 50,000 51,547 51,547 LNB Trust II 7,875 8,119 8,119 Total $ 107,875 111,213 111,213

Selected Quarterly Financial Da

Selected Quarterly Financial Data - Unaudited	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data - Unaudited	Selected Quarterly Financial Data - Unaudited Quarters ended March 31 June 30 (1) September 30 (1) December 31 (In thousands, except per share data) 2016: Interest income $ 85,298 85,555 84,748 90,033 Interest expense 13,746 10,008 7,454 7,091 Net interest income 71,552 75,547 77,294 82,942 Provision for loan losses 1,660 4,199 5,538 2,145 Noninterest income 19,448 20,275 20,818 24,819 Noninterest expenses 63,275 102,122 73,680 68,761 Income before income taxes 26,065 (10,499 ) 18,894 36,855 Income tax expense 8,081 (3,491 ) 4,697 12,361 Net income $ 17,984 (7,008 ) 14,197 24,494 Basic earnings per share $ 0.18 (0.07 ) 0.14 0.24 Diluted earnings per share $ 0.18 (0.07 ) 0.14 0.24 (1) During the quarters ended June 30, 2016 and September 30, 2016, the Company recorded immaterial error corrections of approximately $1.1 million and $1.4 million , respectively, reclassifying amortization of broker fees paid for mortgage loans to interest income from compensation expense. The correction reduced both interest income and compensation expense but had no impact on net income. Quarters ended March 31 June 30 September 30 December 31 (In thousands, except per share data) 2015: Interest income $ 76,880 75,970 81,091 85,639 Interest expense 13,899 13,792 14,150 14,486 Net interest income 62,981 62,178 66,941 71,153 Provision for loan losses 900 1,050 3,167 4,595 Noninterest income 14,625 16,525 18,140 19,546 Noninterest expenses 53,711 55,135 63,804 61,227 Income before income taxes 22,995 22,518 18,110 24,877 Income tax expense 6,825 7,213 5,238 8,684 Net income $ 16,170 15,305 12,872 16,193 Basic earnings per share $ 0.18 0.17 0.14 0.16 Diluted earnings per share $ 0.18 0.17 0.13 0.16 Quarters ended March 31 June 30 September 30 December 31 (In thousands, except per share data) 2014: Interest income $ 75,326 76,987 76,528 76,586 Interest expense 14,204 14,214 14,187 13,982 Net interest income 61,122 62,773 62,341 62,604 Provision for loan losses 7,485 8,285 3,466 1,078 Noninterest income 19,381 16,427 17,737 17,221 Noninterest expenses 53,163 53,806 53,354 55,212 Income before income taxes 19,855 17,109 23,258 23,535 Income tax expense 5,244 4,435 5,926 6,190 Net income $ 14,611 12,674 17,332 17,345 Basic earnings per share $ 0.16 0.14 0.19 0.19 Diluted earnings per share $ 0.16 0.14 0.19 0.19

Subsequent Events - Unaudited

Subsequent Events - Unaudited	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Subsequent Events - Unaudited	Subsequent Events - Unaudited The Company previously announced that it has entered into a purchase and assumption agreement to sell its three bank branches located in the greater Baltimore, Maryland area to Shore Bancshares, Inc.'s banking subsidiary, Shore United Bank. This divestiture includes approximately $216.0 million of deposits, $ 147.0 million of performing loans and $ 40.0 million of cash. The transaction includes a deposit premium of 8.0% and based on the amounts at the time the agreement was signed Northwest anticipates recording a gain of approximately $ 17.0 million . The sale is expected to close during the second quarter of 2017. The following table provides information related to assets and liabilities held-for-sale at December 31, 2016 : Balance at December 31, 2016 Assets held-for-sale: Residential mortgage loans $ 26,406 Home equity loans 15,725 Consumer loans 522 Commercial real estate loans 101,123 Commercial loans 2,884 Total loans 146,660 Accrued interest receivable 416 Premises and equipment, net 5,452 Total assets held-for-sale $ 152,528 Liabilities held-for-sale: Noninterest-bearing demand deposits $ 34,657 Interest-bearing demand deposits 17,181 Money market deposit accounts 45,806 Savings deposits 55,205 Time deposits 62,800 Total deposits 215,649 Accrued interest payable 8 Total liabilities held-for-sale $ 215,657

Summary of Significant Accoun36

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2016
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Nature of Operations	Nature of Operations Northwest Bancshares, Inc., a Maryland corporation headquartered in Warren, Pennsylvania, is the federal savings and loan holding company for its wholly owned subsidiary, Northwest Bank. Northwest Bank, a Pennsylvania chartered savings bank, offers personal and business deposit and loan products as well as investment management and insurance services through its 176 banking locations in Pennsylvania, New York, Ohio and Maryland. Northwest Bank, through its subsidiary Northwest Consumer Discount Company, also offers personal loan products through 49 consumer finance offices in Pennsylvania.
Principles of Consolidation	Principles of Consolidation The consolidated financial statements include the accounts of the Company and its wholly owned subsidiaries after elimination of all intercompany accounts and transactions.
Cash and Cash Equivalents	Cash and Cash Equivalents For purposes of the statement of cash flows, cash and cash equivalents include cash and amounts due from banks, interest-bearing deposits in other financial institutions, federal funds sold, and other short-term investments with original maturities of three months or less.
Investment Securities	Investment Securities We classify marketable securities at the time of purchase as held-to-maturity, available-for-sale, or trading securities. Securities for which management has the intent and ability to hold until maturity are classified as held-to-maturity and are carried at cost, adjusted for amortization of premiums and accretion of discounts on a level yield basis (amortized cost). If it is management’s intent at the time of purchase to hold securities for an indefinite period of time and/or to use such securities as part of its asset/liability management strategy, the securities are classified as available-for-sale and are carried at fair value, with unrealized gains and losses reported as accumulated other comprehensive income/ (loss), a separate component of shareholders’ equity, net of tax. Securities classified as available-for-sale include securities that may be sold in response to changes in interest rates, resultant prepayment risk, or other market factors. Securities that are bought and held principally for the purpose of selling them in the near term are classified as trading and are reported at fair value, with changes in fair value included in earnings. The cost of securities sold is determined on a specific identification basis. We held no securities classified as trading at or for the years ended December 31, 2016 and 2015 . On at least a quarterly basis, we review our investments for other-than-temporary impairment (“OTTI”). An investment security is deemed impaired if the fair value of the investment is less than its amortized cost. If an investment security is determined to be impaired, we evaluate whether the decline in value is other-than-temporary. We consider whether or not we expect to receive all of the contractual cash flows from the investment security based on factors that include, but are not limited to the creditworthiness of the issuer and the historical and projected performance of the underlying collateral. Also, we may evaluate the business and financial outlook of the issuer, as well as broader economic performance indicators. We consider both our intent to sell and the likelihood that we will not have to sell the investment securities before recovery of their cost basis during our evaluation. Impairment that is deemed credit related is recognized in earnings while impairment deemed noncredit related is recorded in accumulated other comprehensive income, if we do not intend to sell nor it is not likely we will be required to sell the investment security. If we intend to sell the investment security or if it is more likely than not that we will be required to sell the investment security, the entire impairment is recorded in earnings. Federal law requires a member institution of the Federal Home Loan Bank ("FHLB") system to hold stock of its district FHLB according to a predetermined formula. This stock is recorded at cost. Quarterly, we evaluate our investment in the FHLB of Pittsburgh for impairment. We evaluate recent and long-term operating performance, liquidity, funding and capital positions, stock repurchase history, dividend history and impact of legislative and regulatory changes. Based on our most recent evaluation, we have determined that no impairment write-downs are currently required.
Loans Receivable	Loans Receivable Our loan portfolio segments consist of Personal Banking and Business Banking loans. Personal Banking loans include the following classes: residential mortgage loans, home equity loans and other consumer loans. Business Banking loans include the following classes: commercial real estate loans and commercial loans. All classes of originated loans are carried at their unpaid principal balance net of any deferred origination fees or costs and the allowance for loan losses. Interest income on loans is credited to income as earned. Interest earned on loans for which no payments were received during the month is accrued at month end. Accrued interest on loans more than 90 days delinquent is reversed and such loans are placed on nonaccrual status. All loans are placed on nonaccrual status when principal or interest is 90 days or more delinquent or when there is reasonable doubt that interest or principal will not be collected in accordance with the contractual terms. Interest receipts on all nonaccrual and impaired loans are recognized as interest revenue when it has been determined that all principal and interest will be collected or are applied to principal when collectability of principal is in doubt. Nonaccrual loans generally are restored to an accrual basis when principal and interest become current and a period of performance has been established in accordance with the contractual terms, typically six months . A loan is considered to be a troubled debt restructured loan ("TDR") when the restructuring constitutes a concession and the borrower is experiencing financial difficulties. TDRs may include modifications of terms of loans, receipts of assets from borrowers in partial or full satisfaction of loans, or a combination thereof. TDRs are impaired loans. A modified loan is determined to be a TDR based on the contractual terms as specified by the original loan agreement or the most recent modification. Once classified a TDR, a loan is removed from such classification under three circumstances: (1) the loan is paid off, (2) the loan is charged off, or (3) if, at the beginning of the current fiscal year, the loan has performed in accordance with the modified terms for a minimum of six consecutive months and at the time of modification the loan’s interest rate represented a then current market interest rate for a loan of similar risk. Loan delinquency is measured based on the number of days since the payment due date. Past due status is measured using the loan’s contractual maturity date. Loan fees and certain direct loan origination costs are deferred and the net deferred fee or cost is then recognized using the level-yield method over the contractual life of the loan as an adjustment to interest income. We identify certain residential mortgage loans which will be sold prior to maturity, as loans held for sale. These loans are recorded at the lower of amortized cost or fair value less estimated cost to sell. At December 31, 2016 and 2015 , there were $36.0 million and $0 residential mortgage loans classified as held for sale, respectively. Acquired loans are recorded at fair value with no carryover of the related allowance for loan losses. 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 excess of cash flows expected at acquisition over the estimated fair value is referred to as the accretable discount and is recognized into interest income over the remaining life of the loan. The difference between contractually required payments at acquisition and the cash flows expected to be collected at acquisition is referred to as the nonaccretable discount. The nonaccretable discount represents estimated future credit losses expected to be incurred over the life of the loan. Subsequent decreases to the expected cash flows require us to evaluate the need for an allowance for loan losses. Subsequent improvements in expected cash flows result in the reversal of a corresponding amount of the nonaccretable discount which we then reclassify as accretable discount that is recognized into interest income over the remaining life of the loan using the interest method. Charge-offs of the principal amount on acquired loans would be first applied to the nonaccretable discount portion of the fair value adjustment. Acquired loans that met the criteria for nonaccrual of interest prior to the acquisition may be considered performing upon acquisition, regardless of whether the customer is contractually delinquent, if we can reasonably estimate the timing and amount of the expected cash flows on such loans and if we expect to fully collect the new carrying value of the loans. As such, we may no longer consider the loan to be nonaccrual or nonperforming and may accrue interest on these loans, including the impact of any accretable discount. We have determined that we can reasonably estimate future cash flows on our current portfolio of acquired loans that are past due 90 days or more and on which we are accruing interest and we expect to fully collect the carrying value of the loans.
Allowance for Loan Losses and Provision for Loan Losses	Allowance for Loan Losses and Provision for Loan Losses Provisions for estimated loan losses and the amount of the allowance for loan losses are based on losses inherent in the loan portfolio that are both probable and can be reasonably estimated at the date of the financial statements. We consider a loan to be impaired when it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement. In evaluating whether a loan is impaired, we consider not only the amount that we expect to collect but also the timing of collection. Generally, if a delay in payment is insignificant (e.g., less than 30 days ), a loan is not deemed to be impaired. Business Banking loans greater than or equal to $1.0 million are reviewed to determine if they should be individually evaluated for impairment. Smaller balance, homogeneous loans (e.g., primarily residential mortgage, home equity and consumer loans) are evaluated collectively for impairment. When a loan is considered to be impaired, the amount of impairment is measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, the loan’s market price, or fair value of the collateral, less estimated cost to sell, if the loan is collateral dependent. Impairment losses are included in the allowance for loan losses. Impaired loans are charged-off or charged down when we believe that the ultimate collectability of a loan is not likely or the collateral value no longer supports the carrying value of the loan. Interest income on non-performing loans is recognized using the cash basis method. For non-performing loans interest collected is credited to income in the period of recovery or applied to reduce principal if there is sufficient doubt about the collectability of principal. The allowance for loan losses is shown as a valuation allowance to loans. The accounting policy for the determination of the adequacy of the allowance by portfolio segment requires us to make numerous complex and subjective estimates and assumptions relating to amounts which are inherently uncertain. The allowance for loan losses is maintained to absorb losses inherent in the loan portfolio as of the balance sheet date. The methodology used to determine the allowance for loan losses is designed to provide procedural discipline in assessing the appropriateness of the allowance for loan losses. Losses are charged against and recoveries are added to the allowance for loan losses. For Business Banking loans the allowance for loan losses consists of: • An allowance for impaired loans; • An allowance for homogenous loans based on historical losses; and • An allowance for homogenous loans based on environmental factors. The allowance for impaired loans is based on individual analysis of all nonperforming loans greater than or equal to $1.0 million . The allowance is measured by the difference between the recorded value of impaired loans and their impaired value. The impaired value is either the present value of the expected future cash flows from the borrower, the market value of the loan, or the fair value of the collateral, less estimated cost to sell. The allowance for homogeneous loans based on historical factors is a rolling three -year average of actual losses incurred, adjusted for a loss realization period (the period of time from the event of loss to loss realization), applied to homogenous pools of loans categorized by similar risk characteristics, not including loans evaluated individually for impairment. The allowance for homogeneous loans based on environmental factors augments the historical loss factors for changes in: economic conditions, lending policies and procedures, the nature and volume of the loan portfolio, management, delinquency trends, loan administration, collateral values, concentrations of credit, and other external factors including legal and regulatory factors. For Personal Banking loans the allowance for loan losses consists of: • An allowance for loans 90 days or more delinquent; • An allowance for homogenous loans based on historical losses; and • An allowance for homogenous loans based on environmental factors. The allowance for loans 90 days or more delinquent is based on the loss history of loans that have become 90 days or more delinquent. We apply a historical loss factor to homogeneous pools of loans that are 90 days or more delinquent. The allowance for homogeneous loans based on historical losses is a rolling three -year average of actual losses incurred, adjusted for a loss realization period, applied to homogenous pools of loans categorized by similar risk characteristics, not including loans that are 90 days or more delinquent. The allocation of the allowance for loan losses is inherently subjective, and the entire allowance for loan losses is available to absorb loan losses regardless of the nature of the loss. Personal Banking loans are charged-off or charged down when they become 180 days delinquent, unless the borrower has filed for bankruptcy. Business Banking loans are charged-off or charged down when, in our opinion, they are no longer collectible or when it has been determined that the collateral value no longer supports the carrying value of the loan, for loans that are collateral dependent. We have not made any material changes to our methodology for the calculation of the allowance for loan losses during the current year.
Real Estate Owned	Real Estate Owned Real estate owned is comprised of property either acquired through foreclosure or voluntarily conveyed by borrowers. These assets are recorded on the date acquired at the lower of the loan balance or fair value of the collateral, less estimated disposition costs, with the fair value being determined by an appraisal. Any initial write-down is charged to the allowance for loan losses. Subsequently, foreclosed assets are valued at the lower of the amount recorded at acquisition date or the current fair value, less estimated disposition costs. Any subsequent write-down or gains or losses realized from the disposition of such property are credited or charged to noninterest income.
Premises and Equipment	Premises and Equipment Premises and equipment are carried at cost, less accumulated depreciation and amortization. Depreciation is accumulated on a straight-line basis over the estimated useful lives of the related assets. Estimated lives range from three to 39 years . Amortization of leasehold improvements is accumulated on a straight-line basis over the terms of the related leases or the useful lives of the related assets, whichever is shorter.
Goodwill	Goodwill Goodwill is generated from the premium paid for an acquisition and is allocated to reporting units, which are either the Company’s reportable segments or one level below. Goodwill is not subject to amortization but is tested for impairment at least annually and possibly more frequently if certain events occur or changes in circumstances arise. Impairment testing requires that the fair value of each reporting unit be compared to its carrying amount, including goodwill. Reporting units are identified based upon analyzing each individual operating segment. A reporting unit is defined as a distinct, separately identifiable component of an operating segment for which complete, discrete financial information is available that management regularly reviews. Determining the fair value of a reporting unit requires a high degree of subjective judgment, including developing cash flow projections, selecting appropriate discount rates, identifying relevant market comparables, incorporating general economic and market conditions and selecting an appropriate control premium. The selection and weighting of the various fair value techniques may result in a higher or lower fair value. Judgment is applied in determining the weightings that are most representative of fair value. We conducted our annual goodwill impairment assessment as of June 30 th through the assistance of an independent third party. We valued each reporting unit by using a weighted average of four valuation methodologies; comparable transaction approach, control premium approach, public market peers approach and discounted cash flow approach. Declines in fair value could result in impairment being identified. At June 30, 2016 and 2015 , we did not identify any individual reporting unit where the fair value was less than the carrying value and no other events have occurred since that date that would warrant an updated valuation. Future changes in the economic environment or the operations of the operating units could cause changes to the variables used, which could give rise to declines in the estimated fair value of the reporting units. There were no changes in our operations that would cause us to update the goodwill impairment tests performed as of June 30, 2016 and 2015 . Accordingly, we have determined that goodwill is not impaired as of December 31, 2016 and 2015 .
Core Deposit Intangibles and Other Identifiable Intangibles	Core Deposit Intangibles and Other Identifiable Intangibles Through the assistance of an independent third party, we analyze and prepare a core deposit study for all bank acquisitions or other identifiable intangible asset study, such as customer lists, for all non-bank acquisitions. The core deposit study reflects the cumulative present value benefit of acquiring deposits versus an alternative source of funding. The other identifiable intangible asset study reflects the cumulative present value benefit of acquiring the income stream from an existing customer base versus developing new business relationships. Based upon analysis, the amount of the premium related to the core deposits or other identifiable intangibles of the business purchased is calculated along with the estimated life of the intangible. The intangible, which is recorded in other intangible assets, is then amortized to expense on an accelerated basis over an approximate life of typically between 7 years to 11 years .
Bank-Owned Life Insurance	Bank-Owned Life Insurance We own insurance on the lives of a certain group of key employees and directors. The policies were purchased to help offset the increase in the costs of various benefit plans, including healthcare, as well as the directors deferred compensation plan. The cash surrender value of these policies is included as an asset on the consolidated statements of financial condition, and any increases in the cash surrender value are recorded as tax-free noninterest income on the consolidated statements of income. In the event of the death of an insured individual under these policies, after distribution to the insured’s beneficiaries, if any, we receive a tax-free death benefit, which is recorded as noninterest income.
Deposits	Deposits Interest on deposits is accrued and charged to expense monthly and is paid or credited in accordance with the terms of the accounts.
Pension Plans	Pension Plans We maintain multiple noncontributory defined benefit pension plans for substantially all of our employees. The net periodic pension cost has been calculated using service cost, interest cost, expected returns on plan assets and net amortization.
Income Taxes	Income Taxes We join with our wholly owned subsidiaries in filing a consolidated federal income tax return. In accordance with an intercompany tax allocation agreement, the applicable federal income tax expense or benefit is allocated to each subsidiary based upon taxable income or loss calculated on a separate company basis. Each subsidiary is responsible for payment of its own federal income tax liability or receives reimbursement of federal income tax benefit. In addition, deferred taxes are calculated and maintained on a separate company basis. We account for income taxes under the asset and liability method. The objective of the asset and liability method is to establish deferred tax assets and liabilities for temporary differences between the financial reporting and tax basis of our assets and liabilities based on the tax rates expected to be in effect when such amounts are realized or settled.
Stock-Related Compensation	Stock-Related Compensation We determine the fair value of each option award, estimated on the grant date, using the Black-Scholes-Merton option-pricing model. The Black-Scholes-Merton option-pricing model uses variables including; expected volatilities, expected term, risk-free discount rate and annual rate of quarterly dividends. Expected volatilities are based on historical volatility of the Company’s stock. The expected terms are based upon actual exercise and forfeiture experience of previous option grants. The risk-free rate is based on yields on U.S. Treasury securities of a similar maturity to the expected term of the options. During the year ended December 31, 2016 , we awarded 660,600 stock options to employees and 64,800 stock options to directors. Option awards are generally granted with an exercise price equal to the closing market price of the Company’s stock on the day before the grant date. The options granted in 2016 vest over a ten -year period, with the first vesting occurring on the grant date. New shares are issued when options are exercised. During the year ended December 31, 2016 , we awarded 310,160 common shares to employees and 24,300 common shares to directors. The common share awards granted in 2016 vest over a ten -year period, with the first vesting occurring on the grant date. For additional information regarding grants of stock options and common shares and ESOP distributions see Note 15. On September 30, 2016, the Northwest Savings Bank Employee Stock Ownership Plan ("ESOP") was terminated. As a result, 1,366,574 unallocated ESOP shares were retired to pay-off the ESOP loan due to the Company. The remaining 401,356 unallocated ESOP shares were distributed into the employees' Northwest Savings Bank 401(k) Plan accounts. This distribution resulted in stock-based compensation expense of $6.3 million for the year ended December 31, 2016. Stock-based employee compensation expense related to common share awards of $3.5 million , $3.0 million and $3.0 million was included in income before income taxes during the years ended December 31, 2016 , 2015 and 2014 , respectively. The effect on net income for the years ended December 31, 2016 , 2015 and 2014 was a reduction of $2.2 million , $1.8 million and $1.8 million , respectively. Total compensation expense for unvested stock options of $4.1 million has yet to be recognized as of December 31, 2016 . The weighted average period over which this remaining stock option expense will be recognized is approximately 4.05 years . The fair value of each option grant is estimated on the date of grant using the Black-Scholes-Merton option-pricing model with the following weighted average assumptions: (1) annual rate of quarterly dividends ranging from 3.2% to 5.1% based on historical dividends and market prices; (2) expected volatility of 17.0% to 22.0% based on historical average montly volatility; (3) risk-free discount rates ranging from 1.7% to 3.1% ; and (4) expected lives of seven to nine years based on previous grants.
Segment Reporting	Segment Reporting We have 2 reportable segments, Community Banking and Consumer Finance. See note 22 for related disclosures.
Derivative financial instruments - interest rate swaps	Derivative financial instruments — interest rate swaps We recognize all derivative financial instruments as either assets or liabilities in the balance sheet and measure those instruments at fair value. The accounting for changes in the fair value of a derivative depends on the intended use of the derivative and the resulting designation. An entity that elects to use hedge accounting is required, at inception, to establish the method it will use for assessing the effectiveness of the hedging derivative and the measurement approach for determining the ineffective aspect of the hedge. Those methods must be consistent with our approach to managing risk. We utilize interest rate swap agreements as part of the management of interest rate risk to hedge the interest rate risk on our trust preferred debentures. Amounts receivable or payable are recognized as accrued under the terms of the agreements and the differential is recorded as an adjustment to interest expense. The interest rate swaps are designated as cash flow hedges, with the effective portion of the derivative’s unrealized gain or loss recorded as a component of other comprehensive income. The ineffective portion of the unrealized gain or loss, if any, would be recorded in other expense. See note 23 for related disclosures.
Off-Balance-Sheet Instruments	Off-Balance-Sheet Instruments In the normal course of business, we extend credit in the form of loan commitments, undisbursed lines of credit, and standby letters of credit. These off-balance-sheet instruments involve, to various degrees, elements of credit and interest rate risk not reported in the consolidated statement of financial condition. We utilize the same underwriting standards for these instruments as other extensions of credit.
Use of Estimates	Use of Estimates The preparation of financial statements, in conformity with accounting principles generally accepted in the United States of America, requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities, disclosure of contingent assets and liabilities at the date of the financial statements, and the reported amount of revenues and expenses during the reporting period. The estimates and assumptions that we deem important to our financial statements relate to the allowance for loan losses, the accounting treatment and valuation of our investment securities portfolio, the analysis of the carrying value of goodwill and income taxes. These estimates and assumptions are based on management’s best estimates and judgment and we evaluate them using historical experience and other factors, including the current economic environment. We adjust our estimates and assumptions when facts and circumstances dictate. As future events cannot be determined, actual results could differ significantly from our estimates.
Reclassification of Prior Years' Statements	Reclassification of Prior Years’ Statements Certain items previously reported have been reclassified to conform with the current year’s reporting format.
Recent Accounting Pronouncements	Recent Accounting Pronouncements In May 2014 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-9, “Revenue from Contracts with Customers (Topic 606)”. This guidance supersedes the revenue recognition requirements in Topic 605, Revenue Recognition, and most industry-specific guidance. The core principle of this guidance requires an entity to recognize revenue upon the transfer of promised goods or services to customers in an amount that reflects the consideration to which the entity expects to be entitled in exchange for those goods or services and provides five steps to be analyzed to accomplish the core principle. This guidance is effective retrospectively for annual reporting periods beginning after December 15, 2017, including interim periods within those years and early adoption is not permitted. We are currently evaluating the impact this standard will have on our results of operations and financial position. In January 2016 the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10)” . This guidance requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. Additionally, this guidance requires entities to use the exit price notion when measuring the fair value of financial instruments for disclosure purposes and eliminates the requirement for public business entities 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. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We are currently evaluating the impact this standard will have on our results of operations and financial position. In February 2016 the FASB issued ASU 2016-2, “Leases” . This guidance requires a lessee to recognize in the statement of financial condition a liability to make lease payments and a right-of-use asset representing the right to use the underlying asset for the term of the lease. Optional periods should only be recognized if the lessee is reasonably certain to exercise the option. For leases with a term of twelve months or less, the lessee is permitted not to recognize lease assets and lease liabilities and should recognize lease expense for such leases generally on a straight-line basis over the term of the lease. This guidance is effective for annual periods beginning after December 15, 2018, including interim periods within those years and early adoption is permitted. We are currently evaluating the impact this standard will have on our results of operations and financial position. In March 2016 the FASB issued ASU 2016-08, “Principal Versus Agent Considerations” . This guidance clarifies the implementation guidance on principal versus agent considerations of ASU 2014-09 "Revenue from Contracts with Customers (Topic 606)" . When another party is involved in providing goods or services to a customer, an entity is required to determine whether the nature of its promise is to provide the specified good or service itself (that is, the entity is a principal) or to arrange for that good or service to be provided by the other party (that is, the entity is an agent). When (or as) an entity that is a principal satisfies a performance obligation, the entity recognizes revenue in the gross amount of consideration to which it expects to be entitled in exchange for the specified good or service transferred to the customer. When (or as) an entity that is an agent satisfies a performance obligation, the entity recognizes revenue in the amount of any fee or commission to which it expects to be entitled in exchange for arranging for the specified good or service to be provided by the other party. This guidance is effective retrospectively for annual reporting periods beginning after December 15, 2017, including interim periods within those years and early adoption is not permitted. We are currently evaluating the impact this standard will have on our results of operations and financial position. In March 2016 the FASB issued ASU 2016-09, “Improvements to Employee Share-based Payment Accounting” . This guidance is part of the FASB's Simplification Initiative and simplifies the accounting for share-based payment transactions, including the income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. This guidance is effective for annual periods beginning after December 15, 2016, including interim periods within those years and early adoption is permitted. We do not expect that this standard will have a material impact on our results of operations or financial position. In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326)-Measurement of Credit Losses on Financial Instruments , which eliminates the probable initial recognition threshold for credit losses requiring, instead, that all financial assets (or group of financial assets) measured at amortized cost be presented at the net amount expected to be collected inclusive of the entity’s current estimate of all lifetime expected credit losses. This guidance also applies to certain off-balance-sheet credit exposures such as unfunded commitments and non-derivative financial guarantees. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset(s) in order to present the net carrying value at the amount expected to be collected on the financial asset. The measurement of expected credit losses is based on relevant information about past events, including historical experience, current conditions, and reasonable and supportable forecasts that affect the collectability of the reported amount. The income statement under this guidance will reflect the initial recognition of current expected credit losses for newly recognized assets, as well as any increases or decreases of expected credit losses that have occurred during the period. This guidance retains many currently-existing disclosures related to the credit quality of an entity’s assets and the related allowance for credit losses amended to reflect the change to an expected credit loss methodology, as well as enhanced disclosures to provide information to users at a more disaggregated level. Upon adoption, ASU 2016-13 provides for a modified retrospective transition by means of a cumulative-effect adjustment to equity as of the beginning of the period in which the guidance is effective, except for debt securities for which an other-than-temporary impairment has previously been recognized. For these debt securities, a prospective transition is provided in order to maintain the same amortized cost prior to and subsequent to the effective date of the ASU. This guidance is effective for annual reporting periods beginning after December 15, 2019, and interim periods within those annual periods with early adoption permitted for fiscal years beginning after December 15, 2018, and interim periods within those annual periods. We are currently evaluating the impact this standard will have on our results of operations and financial position.

Acquisition (Tables)

Acquisition (Tables)	12 Months Ended
	Dec. 31, 2016
Business Combinations [Abstract]
Schedule of the consideration paid, the assets acquired, and the liabilities assumed that were recorded at fair value on the date of acquisition	The following table shows the assets acquired, and the liabilities assumed that were recorded at fair value on the date of acquisition: Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value (1) Cash and cash equivalents (2) $ 1,103,372 Loans 455,857 Core deposit intangible 25,732 Wealth Management intangible 1,143 Other assets 16,978 Total assets acquired 1,603,082 Deposits (1,642,846 ) Other liabilities (5,403 ) Total liabilities assumed (1,648,249 ) Goodwill $ 45,167 (1) Preliminary estimates of fair value have been recorded. (2) Amount is net of $76.5 million deposit premium paid to FNFG.

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2016
Investments, Debt and Equity Securities [Abstract]
Schedule of the portfolio of investment securities available-for-sale	Marketable securities available-for-sale at December 31, 2016 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Debt issued by the U.S. government and agencies: Due in one year or less $ 6 — — 6 Debt issued by government sponsored enterprises: 15500 3 -48 15.45 Due in one year or less 74,980 5 (33 ) 74,952 Due after one year through five years 220,937 203 (2,504 ) 218,636 Due after five years through ten years 585 — (3 ) 582 Due after ten years — — — — Equity securities 3,351 1,095 (6 ) 4,440 Municipal securities: Due in one year or less 2,449 7 — 2,456 Due after one year through five years 9,448 105 (21 ) 9,532 Due after five years through ten years 11,794 137 (1 ) 11,930 Due after ten years 38,141 1,027 (16 ) 39,152 Corporate debt issues: Due after ten years 14,367 2,935 (322 ) 16,980 Residential mortgage-backed securities: Fixed rate pass-through 175,398 1,849 (2,680 ) 174,567 Variable rate pass-through 43,587 2,007 (6 ) 45,588 Fixed rate non-agency CMOs 100 1 — 101 Fixed rate agency CMOs 165,535 185 (3,455 ) 162,265 Variable rate agency CMOs 64,874 306 (167 ) 65,013 Total residential mortgage-backed securities 449,494 4,348 (6,308 ) 447,534 Total marketable securities available-for-sale $ 825,552 9,862 (9,214 ) 826,200 Marketable securities available-for-sale at December 31, 2015 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Debt issued by the U.S. government and agencies: Due in one year or less $ 11 — — 11 Debt issued by government sponsored enterprises: Due in one year or less 15,500 3 (48 ) 15,455 Due after one year through five years 257,463 298 (1,395 ) 256,366 Due after five years through ten years 12,721 14 (23 ) 12,712 Due after ten years 9,815 135 (43 ) 9,907 Equity securities 1,400 500 (6 ) 1,894 Municipal securities: Due in one year or less 1,684 8 — 1,692 Due after one year through five years 14,327 117 (4 ) 14,440 Due after five years through ten years 12,400 323 — 12,723 Due after ten years 52,286 1,727 — 54,013 Corporate debt issues: Due after ten years 14,463 2,417 (405 ) 16,475 Residential mortgage-backed securities: Fixed rate pass-through 118,266 2,480 (420 ) 120,326 Variable rate pass-through 54,292 2,616 (7 ) 56,901 Fixed rate non-agency CMOs 2,519 230 — 2,749 Fixed rate agency CMOs 215,719 389 (3,881 ) 212,227 Variable rate agency CMOs 86,090 476 (52 ) 86,514 Total residential mortgage-backed securities 476,886 6,191 (4,360 ) 478,717 Total marketable securities available-for-sale $ 868,956 11,733 (6,284 ) 874,405
Schedule of the portfolio of investment securities held-to-maturity	Marketable securities held to maturity at December 31, 2015 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Municipal securities: Due after five years through ten years $ 274 1 — 275 Due after ten years 6,336 239 — 6,575 Residential mortgage-backed securities: Fixed rate pass-through 6,458 351 — 6,809 Variable rate pass-through 3,618 41 — 3,659 Fixed rate agency CMOs 14,033 219 — 14,252 Variable rate agency CMOs 970 12 — 982 Total residential mortgage-backed securities 25,079 623 — 25,702 Total marketable securities held-to-maturity $ 31,689 863 — 32,552 Marketable securities held to maturity at December 31, 2016 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Municipal securities: Due after five years through ten years $ — — — — Due after ten years 4,808 65 — 4,873 Residential mortgage-backed securities: Fixed rate pass-through 4,807 217 — 5,024 Variable rate pass-through 2,848 58 — 2,906 Fixed rate agency CMOs 6,674 94 — 6,768 Variable rate agency CMOs 841 14 — 855 Total residential mortgage-backed securities 15,170 383 — 15,553 Total marketable securities held-to-maturity $ 19,978 448 — 20,426
Information regarding the issuers and the carrying values of the entity's mortgage-backed securities	The following table presents information regarding the issuers and the carrying values of our mortgage-backed securities at December 31, 2016 and 2015 : December 31, 2016 2015 Residential mortgage backed securities: FNMA $ 210,373 234,204 GNMA 42,221 48,283 FHLMC 202,822 209,788 SBA 6,608 8,166 Other (including non-agency) 680 3,355 Total residential mortgage-backed securities $ 462,704 503,796
Schedule of the fair value and gross unrealized losses on investment securities, aggregated by investment category and length of time individual securities have been in a continuous unrealized loss position	The following table shows the fair value and gross unrealized losses on investment securities, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position at December 31, 2016 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ 238,003 (2,448 ) 9,205 (92 ) 247,208 (2,540 ) Corporate debt issues — — 2,107 (322 ) 2,107 (322 ) Equity securities — — 544 (6 ) 544 (6 ) Municipal securities 5,621 (37 ) 66 (1 ) 5,687 (38 ) Residential mortgage-backed securities - agency 213,662 (3,837 ) 87,723 (2,471 ) 301,385 (6,308 ) Total temporarily impaired securities $ 457,286 (6,322 ) 99,645 (2,892 ) 556,931 (9,214 ) The following table shows the fair value and gross unrealized losses on investment securities, aggregated by investment category and length of time that the individual securities have been in a continuous unrealized loss position at December 31, 2015 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ 143,751 (723 ) 92,961 (786 ) 236,712 (1,509 ) Corporate debt issues — — 2,021 (405 ) 2,021 (405 ) Equity securities 544 (6 ) — — 544 (6 ) Municipal securities 7,505 (4 ) — — 7,505 (4 ) Residential mortgage-backed securities - agency 122,109 (598 ) 149,889 (3,762 ) 271,998 (4,360 ) Total temporarily impaired securities $ 273,909 (1,331 ) 244,871 (4,953 ) 518,780 (6,284 )
Schedule of categories of investment securities on which other-than-temporary impairment charges have been recorded in earnings	The following table sets forth the categories of investment securities as of December 31, 2016 on which other-than-temporary impairment charges have been recorded in earnings: Total Accumulated Category Amortized cost Fair value Unrealized gain impairment charges Freddie Mac preferred shares $ 1 27 26 (119 ) Trust preferred investments 11,033 13,968 2,935 (7,942 ) Total $ 11,034 13,995 2,961 (8,061 )
Schedule of the cumulative roll forward of credit related impairment losses recognized in earnings for debt securities held and not intended to be sold	The table below shows a cumulative roll forward of credit related impairment losses recognized in earnings for debt securities held and not intended to be sold: December 31, 2016 2015 Beginning balance as of January 1, (1) $ 8,436 8,894 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — Reduction for losses realized during the year (494 ) (98 ) Reduction for securities called realized during the year — (360 ) Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — Ending balance as of December 31, $ 7,942 8,436 (1) The beginning balance represents credit losses included in other-than-temporary impairment charges recognized on debt securities in prior periods.

Loans Receivable and Allowanc39

Loans Receivable and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2016
Receivables [Abstract]
Summary of loans receivable	Loans receivable at December 31, 2016 and 2015 are summarized in the table below: December 31, 2016 December 31, Originated Acquired Total Originated Acquired Total Personal Banking: Residential mortgage loans $ 2,582,218 133,511 2,715,729 2,695,561 45,716 2,741,277 Home equity loans 1,026,315 302,457 1,328,772 1,055,907 131,199 1,187,106 Consumer loans 467,637 163,622 631,259 313,220 197,397 510,617 Total Personal Banking 4,076,170 599,590 4,675,760 4,064,688 374,312 4,439,000 Commercial Banking: Commercial real estate loans 2,140,678 372,991 2,513,669 2,094,710 429,564 2,524,274 Commercial loans 481,543 75,676 557,219 372,540 65,175 437,715 Total Commercial Banking 2,622,221 448,667 3,070,888 2,467,250 494,739 2,961,989 Total loans receivable, gross 6,698,391 1,048,257 7,746,648 6,531,938 869,051 7,400,989 Deferred loan costs 20,081 2,294 22,375 14,806 5,259 20,065 Allowance for loan losses (55,293 ) (5,646 ) (60,939 ) (60,970 ) (1,702 ) (62,672 ) Undisbursed loan proceeds: Residential mortgage loans (11,638 ) — (11,638 ) (10,778 ) — (10,778 ) Commercial real estate loans (168,595 ) (2,985 ) (171,580 ) (159,553 ) (13,287 ) (172,840 ) Commercial loans (26,168 ) (2,290 ) (28,458 ) (11,132 ) (4,183 ) (15,315 ) Total loans receivable, net $ 6,456,778 1,039,630 7,496,408 6,304,311 855,138 7,159,449
Schedule of information related to the outstanding principal balance and related carrying value of acquired loans	The following table provides information related to the outstanding principal balance and related carrying value of acquired loans for the dates indicated: December 31, December 31, 2016 2015 Acquired loans evaluated individually for future credit losses: Outstanding principal balance $ 16,108 21,069 Carrying value 12,665 16,867 Acquired loans evaluated collectively for future credit losses: Outstanding principal balance 1,040,378 848,194 Carrying value 1,032,611 839,973 Total acquired loans: Outstanding principal balance 1,056,486 869,263 Carrying value 1,045,276 856,840
Schedule of the changes in the accretable discount	The following table provides information related to the changes in the accretable discount, which includes income recognized from contractual cash flows for the dates indicated: Total Balance at December 31, 2014 $ — LNB Bancorp, Inc. acquisition 1,672 Accretion (377 ) Net reclassification from nonaccretable yield 724 Balance at December 31, 2015 2,019 Accretion (1,170 ) Net reclassification from nonaccretable yield 1,338 Balance at December 31, 2016 $ 2,187
Schedule of the changes in the allowance for losses on loans receivable	The following table provides information related to changes in the allowance for losses on loans receivable for the year ended December 31, 2015 : Balance Provision Charge-offs Recoveries Balance Originated loans: Personal Banking: Residential mortgage loans $ 4,692 (96 ) (1,057 ) 264 5,581 Home equity loans 3,941 693 (1,716 ) 414 4,550 Consumer loans 7,488 7,985 (8,073 ) 1,458 6,118 Total Personal Banking 16,121 8,582 (10,846 ) 2,136 16,249 Commercial Banking: Commercial real estate loans 32,348 540 (5,741 ) 4,160 33,389 Commercial loans 12,501 2,768 (7,814 ) 4,032 13,515 Total Commercial Banking 44,849 3,308 (13,555 ) 8,192 46,904 Unallocated — (4,365 ) — — 4,365 Total originated loans 60,970 7,525 (24,401 ) 10,328 67,518 Acquired loans: Personal Banking: Residential mortgage loans 18 47 (69 ) 40 — Home equity loans 101 247 (708 ) 562 — Consumer loans 110 188 (201 ) 123 — Total Personal Banking 229 482 (978 ) 725 — Commercial Banking: Commercial real estate loans 1,439 1,545 (585 ) 479 — Commercial loans 34 160 (369 ) 243 — Total Commercial Banking 1,473 1,705 (954 ) 722 — Total acquired loans 1,702 2,187 (1,932 ) 1,447 — Total $ 62,672 9,712 (26,333 ) 11,775 67,518 The following table provides information related to changes in the allowance for losses on loans receivable for the year ended December 31, 2016 : Balance Provision Charge-offs Recoveries Balance Originated loans: Personal Banking: Residential mortgage loans $ 4,656 2,906 (3,228 ) 286 4,692 Home equity loans 3,486 293 (1,090 ) 342 3,941 Consumer loans 7,974 9,052 (10,225 ) 1,659 7,488 Total Personal Banking 16,116 12,251 (14,543 ) 2,287 16,121 Commercial Banking: Commercial real estate loans 23,667 (9,819 ) (2,403 ) 3,541 32,348 Commercial loans 15,510 4,834 (4,165 ) 2,340 12,501 Total Commercial Banking 39,177 (4,985 ) (6,568 ) 5,881 44,849 Total originated loans 55,293 7,266 (21,111 ) 8,168 60,970 Acquired loans: Personal Banking: Residential mortgage loans 71 146 (252 ) 159 18 Home equity loans 1,047 2,065 (1,449 ) 330 101 Consumer loans 653 1,072 (680 ) 151 110 Total Personal Banking 1,771 3,283 (2,381 ) 640 229 Commercial Banking: Commercial real estate loans 3,008 2,116 (1,337 ) 790 1,439 Commercial loans 867 877 (52 ) 8 34 Total Commercial Banking 3,875 2,993 (1,389 ) 798 1,473 Total acquired loans 5,646 6,276 (3,770 ) 1,438 1,702 Total $ 60,939 13,542 (24,881 ) 9,606 62,672 The following table provides information related to changes in the allowance for losses on loans receivable for the year ended December 31, 2014 : Balance Provision Charge-offs Recoveries Balance Personal Banking: Residential mortgage loans $ 5,581 (556 ) (2,181 ) 443 7,875 Home equity loans 4,550 (1,106 ) (1,783 ) 194 7,245 Consumer loans 6,118 5,864 (6,423 ) 1,190 5,487 Total Personal Banking 16,249 4,202 (10,387 ) 1,827 20,607 Commercial Banking: Commercial real estate loans 33,389 4,417 (8,422 ) 2,195 35,199 Commercial loans 13,515 11,992 (11,936 ) 2,579 10,880 Total Commercial Banking 46,904 16,409 (20,358 ) 4,774 46,079 Unallocated 4,365 (297 ) — — 4,662 Total $ 67,518 20,314 (30,745 ) 6,601 71,348
Schedule of loan portfolio by portfolio segment and by class of financing receivable	The following table provides information related to the loan portfolio by portfolio segment and by class of financing receivable as of December 31, 2016 : Recorded investment in loans receivable Allowance for loan losses Recorded investment in loans on nonaccrual (1) Recorded investment in loans 90 days or more past maturity and still accruing TDRs (1) Allowance for TDRs Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,714,764 4,727 18,264 — 7,299 708 — Home equity loans 1,328,772 4,533 7,865 — 1,813 450 4 Consumer loans 642,961 8,627 5,109 85 — — — Total Personal Banking 4,686,497 17,887 31,238 85 9,112 1,158 4 Commercial Banking: Commercial real estate loans 2,342,089 26,675 38,724 564 24,483 2,072 417 Commercial loans 528,761 16,377 9,574 — 9,331 1,360 17 Total Commercial Banking 2,870,850 43,052 48,298 564 33,814 3,432 434 Total $ 7,557,347 60,939 79,536 649 42,926 4,590 438 (1) Includes $16.3 million of nonaccrual TDRs. The following table provides information related to the loan portfolio by portfolio segment and by class of financing receivable as of December 31, 2015 : Recorded investment in loans receivable Allowance for loan losses Recorded investment in loans on nonaccrual (1) Recorded TDRs (1) Allowance for TDRs Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,740,892 4,710 19,772 4 6,360 1,189 — Home equity loans 1,187,106 4,042 7,522 — 2,298 605 — Consumer loans 520,289 7,598 3,452 976 — — — Total Personal Banking 4,448,287 16,350 30,746 980 8,658 1,794 — Commercial Banking: Commercial real estate loans 2,351,434 33,787 33,421 206 31,970 2,257 241 Commercial loans 422,400 12,535 7,495 148 10,487 631 79 Total Commercial Banking 2,773,834 46,322 40,916 354 42,457 2,888 320 Total $ 7,222,121 62,672 71,662 1,334 51,115 4,682 320 (1) Includes $21.1 million of nonaccrual TDRs.
Schedule of the composition of impaired loans by portfolio segment and by class of financing receivable	The following table provides information related to purchased credit impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2016 : Carrying value Outstanding principal balance Related impairment reserve Average recorded investment in impaired loans Interest income/ accretion recognized Personal Banking: Residential mortgage loans $ 1,319 2,062 204 1,650 202 Home equity loans 1,363 2,669 8 1,724 185 Consumer loans 136 303 3 201 51 Total Personal Banking 2,818 5,034 215 3,575 438 Commercial Banking: Commercial real estate loans 9,596 10,809 52 10,942 721 Commercial loans 251 265 — 249 11 Total Commercial Banking 9,847 11,074 52 11,191 732 Total $ 12,665 16,108 267 14,766 1,170 The following table provides information related to the composition of impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2016 : Nonaccrual loans 90 or more days delinquent Nonaccrual loans less than 90 days delinquent Loans less than 90 days delinquent reviewed for impairment TDRs less than 90 days delinquent not included elsewhere Total impaired loans Average recorded investment in impaired loans Interest income recognized on impaired loans Personal Banking: Residential mortgage loans $ 13,169 5,095 — 5,929 24,193 24,483 1,079 Home equity loans 5,552 2,313 — 1,439 9,304 9,234 496 Consumer loans 3,823 1,286 — — 5,109 3,703 166 Total Personal Banking 22,544 8,694 — 7,368 38,606 37,420 1,741 Commercial Banking: Commercial real estate loans 19,264 19,460 3,622 11,582 53,928 64,350 2,864 Commercial loans 3,373 6,201 2,837 3,116 15,527 16,905 991 Total Commercial Banking 22,637 25,661 6,459 14,698 69,455 81,255 3,855 Total $ 45,181 34,355 6,459 22,066 108,061 118,675 5,596 The following table provides information related to the composition of impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2015 : Nonaccrual loans 90 or more days delinquent Nonaccrual loans less than 90 days delinquent Loans less than 90 days delinquent reviewed for impairment TDRs less than 90 days delinquent not included elsewhere Total impaired loans Average recorded investment in impaired loans Interest income recognized on impaired loans Personal Banking: Residential mortgage loans $ 15,810 3,962 — 5,086 24,858 24,554 944 Home equity loans 5,650 1,872 — 1,847 9,369 9,644 497 Consumer loans 2,900 552 — — 3,452 2,977 101 Total Personal Banking 24,360 6,386 — 6,933 37,679 37,175 1,542 Commercial Banking: Commercial real estate loans 16,449 16,972 16,121 16,467 66,009 77,166 3,226 Commercial loans 2,459 5,036 2,014 4,654 14,163 16,187 694 Total Commercial Banking 18,908 22,008 18,135 21,121 80,172 93,353 3,920 Total $ 43,268 28,394 18,135 28,054 117,851 130,528 5,462 The following table provides information related to the composition of impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2014 : Nonaccrual loans 90 or more days delinquent Nonaccrual loans less than 90 days delinquent Loans less than 90 days delinquent reviewed for impairment TDRs less than 90 days delinquent not included elsewhere Total impaired loans Average recorded investment in impaired loans Interest income recognized on impaired loans Personal Banking: Residential mortgage loans $ 17,696 3,498 — 5,845 27,039 28,227 817 Home equity loans 6,606 2,963 — 1,706 11,275 11,753 485 Consumer loans 2,450 370 — — 2,820 2,383 66 Total Personal Banking 26,752 6,831 — 7,551 41,134 42,363 1,368 Commercial Banking: Commercial real estate loans 11,099 27,548 26,400 12,128 74,337 90,187 3,589 Commercial loans 3,475 4,103 5,266 6,026 21,708 27,088 914 Total Commercial Banking 14,574 31,651 31,666 18,154 96,045 117,275 4,503 Total $ 41,326 38,482 31,666 25,705 137,179 159,638 5,871
Schedule of the evaluation of impaired loans by portfolio segment and by class of financing receivable	The following table provides information related to the evaluation of impaired loans by portfolio segment and by class of financing receivable as of and for the year ended December 31, 2016 : Loans collectively evaluated for impairment Loans individually evaluated for impairment Loans individually evaluated for impairment for which there is a related impairment reserve Related impairment reserve Loans individually evaluated for impairment for which there is no related reserve Personal Banking: Residential mortgage loans $ 2,706,484 8,280 8,280 709 — Home equity loans 1,326,958 1,814 1,814 450 — Consumer loans 642,835 126 126 29 — Total Personal Banking 4,676,277 10,220 10,220 1,188 — Commercial Banking: Commercial real estate loans 2,309,186 32,903 27,594 3,545 5,309 Commercial loans 518,449 10,312 10,242 1,390 70 Total Commercial Banking 2,827,635 43,215 37,836 4,935 5,379 Total $ 7,503,912 53,435 48,056 6,123 5,379 The following table provides information related to the evaluation of impaired loans by portfolio segment and by class of financing receivable as of and for the year ended December 31, 2015 : Loans collectively evaluated for impairment Loans individually evaluated for impairment Loans individually evaluated for impairment for which there is a related impairment reserve Related impairment reserve Loans individually evaluated for impairment for which there is no related reserve Personal Banking: Residential mortgage loans $ 2,733,741 7,151 7,151 1,189 — Home equity loans 1,184,808 2,298 2,298 605 — Consumer loans 520,159 130 130 50 — Total Personal Banking 4,438,708 9,579 9,579 1,844 — Commercial Banking: Commercial real estate loans 2,297,599 53,835 35,937 2,675 17,898 Commercial loans 411,342 11,058 7,673 489 3,385 Total Commercial Banking 2,708,941 64,893 43,610 3,164 21,283 Total $ 7,147,649 74,472 53,189 5,008 21,283
Schedule of roll forward of troubled debt restructurings	The following table provides a roll forward of troubled debt restructurings for the periods indicated: For the years ended December 31, 2016 2015 Number of contracts Amount Number of contracts Amount Beginning TDR balance: 227 $ 51,115 248 $ 61,788 New TDRs 34 6,365 26 8,537 Re-modified TDRs 7 3,414 3 6,386 Net paydowns (9,037 ) (13,270 ) Charge-offs: Residential mortgage loans — — — — Home equity loans — — 4 (159 ) Commercial real estate loans 1 (120 ) 4 (179 ) Commercial loans 2 (142 ) 2 (387 ) Paid-off loans: Residential mortgage loans 4 (151 ) 2 (109 ) Home equity loans (534 ) 5 (194 ) Commercial real estate loans 19 (6,170 ) 15 (9,208 ) Commercial loans 10 (1,814 ) 14 (1,728 ) Transferred to real estate owned Commercial real estate loans — — 1 (362 ) Ending TDR balance: 225 $ 42,926 227 $ 51,115 Accruing TDRs $ 26,580 $ 29,997 Non-accrual TDRs 16,346 21,118
Schedule of troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable	The following table provides information related to troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable during the year ended December 31, 2016 : Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 7 $ 1,199 1,177 114 Home equity loans 7 475 471 110 Consumer loans — — — — Total Personal Banking 14 1,674 1,648 224 Commercial Banking: Commercial real estate loans 7 3,729 3,643 485 Commercial loans 20 4,376 2,218 508 Total Commercial Banking 27 8,105 5,861 993 Total 41 $ 9,779 7,509 1,217 Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings modified within the previous twelve months that have subsequently defaulted: Personal Banking: Residential mortgage loans — $ — — — Home equity loans — — — — Consumer loans — — — — Total Personal Banking — — — — Commercial Banking: Commercial real estate loans 1 429 425 31 Commercial loans 3 533 533 533 Total Commercial Banking 4 962 958 564 Total 4 $ 962 958 564 The following table provides information related to troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable during the year ended December 31, 2015 : Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 6 $ 364 357 21 Home equity loans 3 101 97 21 Consumer loans — — — — Total Personal Banking 9 465 454 42 Commercial Banking: Commercial real estate loans 11 12,258 12,243 1,047 Commercial loans 9 2,200 2,184 156 Total Commercial Banking 20 14,458 14,427 1,203 Total 29 $ 14,923 14,881 1,245 At December 31, 2015, no TDRs that were modified in the previous twelve months had subsequently defaulted. The following table provides information related to troubled debt restructurings (including re-modified TDRs) by portfolio segment and by class of financing receivable during the year ended December 31, 2014 : Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 17 $ 2,802 2,690 210 Home equity loans 6 570 507 1 Consumer loans — — — — Total Personal Banking 23 3,372 3,197 211 Commercial Banking: Commercial real estate loans 11 2,010 1,793 202 Commercial loans 23 7,750 6,818 1,491 Total Commercial Banking 34 9,760 8,611 1,693 Total 57 $ 13,132 11,808 1,904 Number of contracts Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings modified within the previous twelve months that have subsequently defaulted: Personal Banking: Residential mortgage loans 1 $ 78 77 — Home equity loans 1 360 331 1 Consumer loans — — — — Total Personal Banking 2 438 408 1 Commercial Banking: Commercial real estate loans 1 12 5 1 Commercial loans 1 50 64 6 Total Commercial Banking 2 62 69 7 Total 4 $ 500 477 8
Schedule of troubled debt restructurings (including re-modified TDRs) by type of modification by portfolio segment and by class of financing receivable	The following table provides information for troubled debt restructurings (including re-modified TDRs) by type of modification, by portfolio segment and class of financing receivable during the year ended December 31, 2016 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 7 $ 358 — 771 48 1,177 Home equity loans 7 120 — 3 348 471 Consumer loans — — — — — — Total Personal Banking 14 478 — 774 396 1,648 Commercial Banking: Commercial real estate loans 7 — 425 1,980 1,238 3,643 Commercial loans 20 — 328 1,178 712 2,218 Total Commercial Banking 27 — 753 3,158 1,950 5,861 Total 41 $ 478 753 3,932 2,346 7,509 The following table provides information for troubled debt restructurings (including re-modified TDRs) by type of modification, by portfolio segment and class of financing receivable during the year ended December 31, 2015 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 6 $ 71 — 110 176 357 Home equity loans 3 96 — 1 — 97 Consumer loans — — — — — — Total Personal Banking 9 167 — 111 176 454 Commercial Banking: Commercial real estate loans 11 174 — 11,961 108 12,243 Commercial loans 9 — — 1,264 920 2,184 Total Commercial Banking 20 174 — 13,225 1,028 14,427 Total 29 $ 341 — 13,336 1,204 14,881
Schedule of re-modified troubled debt restructurings by portfolio segment and by class of financing receivable	The following table provides information related to re-modified troubled debt restructurings by portfolio segment and by class of financing receivable for the year ended December 31, 2016 : Number of re- modified Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans — $ — — — — — Home equity loans 1 — — — 192 192 Consumer loans — — — — — — Total Personal Banking 1 — — — 192 192 Commercial Banking: Commercial real estate loans 2 — — 1,329 173 1,502 Commercial loans 4 — 502 — — 502 Total Commercial Banking 6 — 502 1,329 173 2,004 Total 7 $ — 502 1,329 365 2,196 The following table provides information related to re-modified troubled debt restructurings by portfolio segment and by class of financing receivable for the year ended December 31, 2015 : Number of re- modified Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 1 $ — — — 45 45 Home equity loans 1 83 — — — 83 Consumer loans — — — — — — Total Personal Banking 2 83 — — 45 128 Commercial Banking: Commercial real estate loans 1 — — 6,256 — 6,256 Commercial loans — — — — — — Total Commercial Banking 1 — — 6,256 — 6,256 Total 3 $ 83 — 6,256 45 6,384
Schedule of loan delinquencies	The following table provides information related to loan delinquencies as of December 31, 2016 : 30-59 days delinquent 60-89 days delinquent 90 days or greater delinquent Total delinquency Current Total loans 90 days or greater delinquent and accruing (1) Originated loans Personal Banking: Residential mortgage loans $ 26,212 5,806 12,792 44,810 2,536,443 2,581,253 — Home equity loans 5,785 1,305 4,783 11,873 1,014,442 1,026,315 — Consumer loans 8,598 3,204 3,518 15,320 461,725 477,045 — Total Personal Banking 40,595 10,315 21,093 72,003 4,012,610 4,084,613 — Commercial Banking: Commercial real estate loans 7,674 3,674 16,508 27,856 1,944,227 1,972,083 — Commercial loans 1,067 1,957 3,107 6,131 449,244 455,375 — Total Commercial Banking 8,741 5,631 19,615 33,987 2,393,471 2,427,458 — Total originated loans 49,336 15,946 40,708 105,990 6,406,081 6,512,071 — Acquired loans Personal Banking: Residential mortgage loans 1,174 421 829 2,424 131,087 133,511 452 Home equity loans 1,020 258 973 2,251 300,206 302,457 204 Consumer loans 1,270 405 320 1,995 163,921 165,916 15 Total Personal Banking 3,464 1,084 2,122 6,670 595,214 601,884 671 Commercial Banking: Commercial real estate loans 2,703 821 4,762 8,286 361,720 370,006 2,006 Commercial loans 111 124 413 648 72,738 73,386 147 Total Commercial Banking 2,814 945 5,175 8,934 434,458 443,392 2,153 Total acquired loans 6,278 2,029 7,297 15,604 1,029,672 1,045,276 2,824 Total loans $ 55,614 17,975 48,005 121,594 7,435,753 7,557,347 2,824 (1) Represents acquired loans that were originally recorded at fair value upon acquisition. These loans are considered to be accruing because we can reasonably estimate future cash flows on and expect to fully collect the carrying value of these loans. Therefore, we are accreting the difference between the carrying value and their expected cash flows into interest income. The following table provides information related to loan delinquencies as of December 31, 2015 : 30-59 days delinquent 60-89 days delinquent 90 days or greater delinquent Total delinquency Current Total loans 90 days or greater delinquent and accruing (1) Personal Banking: Residential mortgage loans $ 25,503 7,541 15,564 48,608 2,646,568 2,695,176 — Home equity loans 4,870 1,836 5,251 11,957 1,043,950 1,055,907 — Consumer loans 6,092 2,340 2,857 11,289 306,344 317,633 — Total Personal Banking 36,465 11,717 23,672 71,854 3,996,862 4,068,716 — Commercial Banking: Commercial real estate loans 22,212 6,875 14,942 44,029 1,891,128 1,935,157 — Commercial loans 1,703 598 2,449 4,750 356,658 361,408 — Total Commercial Banking 23,915 7,473 17,391 48,779 2,247,786 2,296,565 — Total originated loans 60,380 19,190 41,063 120,633 6,244,648 6,365,281 — Acquired loans Personal Banking: Residential mortgage loans 440 249 786 1,475 44,241 45,716 540 Home equity loans 936 642 861 2,439 128,760 131,199 462 Consumer loans 1,009 181 69 1,259 201,397 202,656 26 Total Personal Banking 2,385 1,072 1,716 5,173 374,398 379,571 1,028 Commercial Banking: Commercial real estate loans 2,665 1,353 4,089 8,107 408,170 416,277 2,582 Commercial loans 1,165 — 150 1,315 59,677 60,992 140 Total Commercial Banking 3,830 1,353 4,239 9,422 467,847 477,269 2,722 Total acquired loans 6,215 2,425 5,955 14,595 842,245 856,840 3,750 Total loans $ 66,595 21,615 47,018 135,228 7,086,893 7,222,121 3,750
Schedule of credit quality indicators	The following table sets forth information about credit quality indicators as of December 31, 2016 : Pass Special mention Substandard Doubtful Loss Total Originated loans Personal Banking: Residential mortgage loans $ 2,564,988 — 16,265 — — 2,581,253 Home equity loans 1,018,898 — 7,417 — — 1,026,315 Consumer loans 473,950 — 3,095 — — 477,045 Total Personal Banking 4,057,836 — 26,777 — — 4,084,613 Commercial Banking: Commercial real estate loans 1,821,548 36,321 114,214 — — 1,972,083 Commercial loans 401,866 15,203 38,306 — — 455,375 Total Commercial Banking 2,223,414 51,524 152,520 — — 2,427,458 Total originated loans 6,281,250 51,524 179,297 — — 6,512,071 Acquired loans Personal Banking: Residential mortgage loans 131,717 — 1,794 — — 133,511 Home equity loans 300,100 — 2,357 — — 302,457 Consumer loans 165,094 — 822 — — 165,916 Total Personal Banking 596,911 — 4,973 — — 601,884 Commercial Banking: Commercial real estate loans 331,780 7,403 30,823 — — 370,006 Commercial loans 68,127 1,989 3,270 — — 73,386 Total Commercial Banking 399,907 9,392 34,093 — — 443,392 Total acquired loans 996,818 9,392 39,066 — — 1,045,276 Total loans $ 7,278,068 60,916 218,363 — — 7,557,347 The following table sets forth information about credit quality indicators as of December 31, 2015 : Pass Special mention Substandard Doubtful Loss Total Personal Banking: Residential mortgage loans $ 2,680,562 — 13,274 — 1,340 2,695,176 Home equity loans 1,048,397 — 7,510 — — 1,055,907 Consumer loans 315,159 — 2,474 — — 317,633 Total Personal Banking 4,044,118 — 23,258 — 1,340 4,068,716 Commercial Banking: Commercial real estate loans 1,778,140 46,518 110,384 115 — 1,935,157 Commercial loans 299,455 23,023 37,820 1,110 — 361,408 Total Commercial Banking 2,077,595 69,541 148,204 1,225 — 2,296,565 Total originated loans 6,121,713 69,541 171,462 1,225 1,340 6,365,281 Acquired loans Personal Banking: Residential mortgage loans 44,930 — 786 — — 45,716 Home equity loans 130,338 — 861 — — 131,199 Consumer loans 202,587 — 69 — — 202,656 Total Personal Banking 377,855 — 1,716 — — 379,571 Commercial Banking: Commercial real estate loans 392,811 6,872 16,594 — — 416,277 Commercial loans 59,948 707 337 — — 60,992 Total Commercial Banking 452,759 7,579 16,931 — — 477,269 Total acquired loans 830,614 7,579 18,647 — — 856,840 Total loans $ 6,952,327 77,120 190,109 1,225 1,340 7,222,121
Schedule of financial instruments with off-balance-sheet risk	Financial instruments with off-balance-sheet risk as of December 31, 2016 and 2015 are presented in the following table: December 31, 2016 2015 Loan commitments $ 109,032 186,731 Undisbursed lines of credit 843,457 562,284 Standby letters of credit 25,039 32,719 Total $ 977,528 781,734

Accrued Interest Receivable (Ta

Accrued Interest Receivable (Tables)	12 Months Ended
	Dec. 31, 2016
Interest Receivable and Other Assets [Abstract]
Schedule of accrued interest receivable	Accrued interest receivable as of December 31, 2016 and 2015 is presented in the following table: December 31, 2016 2015 Investment securities $ 1,613 1,852 Mortgage-backed securities 910 960 Loans receivable 19,176 18,260 $ 21,699 21,072

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2016
Property, Plant and Equipment [Abstract]
Schedule of premises and equipment	Premises and equipment at December 31, 2016 and 2015 are summarized by major classification in the following table: December 31, 2016 2015 Land and land improvements $ 21,229 23,257 Office buildings and improvements 156,162 153,003 Furniture, fixtures and equipment 120,391 115,576 Leasehold improvements 19,859 19,239 Total, at cost 317,641 311,075 Less accumulated depreciation and amortization (156,456 ) (156,724 ) Premises and equipment, net $ 161,185 154,351
Schedule of minimum annual rentals	Minimum annual rentals by fiscal year are summarized in the following table: 2017 $ 4,846 2018 3,697 2019 2,579 2020 2,015 2021 1,596 Thereafter 5,595 Total $ 20,328

Goodwill and Other Intangible42

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2016
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of intangible assets subject to amortization	The following table provides information for intangible assets subject to amortization for the years ended December 31, 2016 and 2015 : December 31, 2016 2015 Amortizable intangible assets: Core deposit intangibles — gross $ 37,953 30,578 Acquisitions 25,732 7,375 Less: accumulated amortization (34,378 ) (31,192 ) Core deposit intangibles — net $ 29,307 6,761 Customer and Contract intangible assets — gross 8,496 8,234 Acquisitions 1,978 262 Less: accumulated amortization (7,348 ) (6,275 ) Customer and Contract intangible assets — net $ 3,126 2,221
Schedule of the actual aggregate amortization expense as well as estimated aggregate amortization expense, based upon current levels of intangible assets	The following information shows the actual aggregate amortization expense for the years ended December 31, 2016 , 2015 and 2014 as well as the estimated aggregate amortization expense, based upon current levels of intangible assets, for each of the five succeeding fiscal years: For the year ended December 31, 2014 $ 1,323 For the year ended December 31, 2015 1,688 For the year ended December 31, 2016 4,259 For the year ending December 31, 2017 6,764 For the year ending December 31, 2018 5,848 For the year ending December 31, 2019 4,933 For the year ending December 31, 2020 4,017 For the year ending December 31, 2021 3,188
Schedule of the changes in carrying amount of goodwill	The following table provides information for the changes in the carrying amount of goodwill: Community Banks Consumer Finance Total Balance at December 31, 2014 $ 173,710 1,613 175,323 Goodwill acquired - LNB 86,238 — 86,238 Goodwill acquired - Petruso Insurance Agency 175 — 175 Balance at December 31, 2015 260,123 1,613 261,736 Goodwill acquired - FNFG 45,167 — 45,167 Goodwill acquired - Best Insurance Agency 404 — 404 Goodwill acquired - Winan Insurance Agency 113 — 113 Balance at December 31, 2016 $ 305,807 1,613 307,420

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2016
Deposits [Abstract]
Schedule of deposit balances	Deposit balances at December 31, 2016 and 2015 are shown in the table below: December 31, 2016 2015 Savings deposits $ 1,622,879 1,386,017 Interest-bearing demand deposits 1,428,317 1,080,086 Noninterest-bearing demand deposits 1,448,972 1,177,256 Money market demand accounts 1,841,567 1,274,504 Time deposits 1,540,586 1,694,718 Total deposits $ 7,882,321 6,612,581
Summarizes the contractual maturity of the certificate accounts	The following table summarizes the contractual maturity of time deposits at December 31, 2016 and 2015 : December 31, 2016 2015 Due within 12 months $ 836,525 929,351 Due between 12 and 24 months 311,976 448,497 Due between 24 and 36 months 153,708 205,635 Due between 36 and 48 months 90,777 21,414 Due between 48 and 60 months 134,687 78,796 After 60 months 12,913 11,025 Total time deposits $ 1,540,586 1,694,718
Summarizes the interest expense incurred on the deposits	The following table summarizes the interest expense incurred on the respective deposits for the years ended December 31, 2016 , 2015 and 2014 : Years ended December 31, 2016 2015 2014 Savings deposits $ 3,218 3,387 3,286 Interest-bearing demand deposits 462 568 587 Money market demand accounts 3,621 3,222 3,174 Time deposits 16,164 16,878 18,275 Total interest expense $ 23,465 24,055 25,322

Borrowed Funds (Tables)

Borrowed Funds (Tables)	12 Months Ended
	Dec. 31, 2016
Debt Disclosure [Abstract]
Schedule of borrowed funds	Borrowed funds at December 31, 2016 and 2015 are presented in the following table: December 31, 2016 2015 Amount Average rate Amount Average rate Term notes payable to the FHLB of Pittsburgh: Due within one year $ — — % 145,343 3.24 % Due between one and two years — — % 125,000 3.68 % Due between two and three years — — % 140,000 3.73 % Due between three and four years — — % 125,000 4.32 % Due between four and five years — — % 95,000 3.65 % Due between five and ten years — — % 120,000 3.68 % — 750,343 Revolving line of credit, FHLB of Pittsburgh — — % 106,000 0.43 % Collateralized borrowings, due within one year 142,899 0.17 % 118,664 0.22 % Total borrowed funds $ 142,899 975,007

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2016
Income Tax Disclosure [Abstract]
Schedule of allocation of income tax	Total income tax was allocated for the years ended December 31, 2016 , 2015 and 2014 as follows: Years ended December 31, 2016 2015 2014 Income before income taxes $ 21,648 27,960 21,795 Shareholders’ equity for unrealized (loss)/ gain on securities available-for-sale (1,871 ) (85 ) 4,286 Shareholders’ equity for tax benefit for excess of fair value above cost of stock benefit plans (1,425 ) (332 ) (945 ) Shareholders’ equity for pension adjustment (2,455 ) (848 ) (12,985 ) Shareholders’ equity for swap fair value adjustment 539 699 618 Unallocated income tax $ 16,436 27,394 12,769
Schedule of income tax expense (benefit) applicable to income before taxes	Income tax expense applicable to income before taxes consists of: Years ended December 31, 2016 2015 2014 Current $ 18,914 21,670 13,200 Deferred 2,734 6,290 8,595 Total income tax expense $ 21,648 27,960 21,795
Schedule of reconciliation of the expected federal statutory rate to the effective rate	A reconciliation of the expected federal statutory income tax rate to the effective rate, expressed as a percentage of pretax income for the years ended December 31, 2016 , 2015 and 2014 , is as follows: Years ended December 31, 2016 2015 2014 Expected tax rate 35.0 % 35.0 % 35.0 % Tax-exempt interest income (3.3 )% (3.0 )% (4.1 )% State income tax, net of federal benefit 1.2 % 2.9 % 1.7 % Bank-owned life insurance (2.6 )% (1.7 )% (1.8 )% Dividends on stock plans (2.0 )% (0.8 )% (4.0 )% Low income housing and historic tax credits (1.0 )% (1.4 )% (0.9 )% Non-deductible acquisition expense — % 0.5 % — % ESOP termination 3.4 % — % — % Other (0.3 )% 0.1 % 0.1 % Effective tax rate 30.4 % 31.6 % 26.0 %
Tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities	The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2016 and 2015 are presented below: December 31, 2016 2015 Deferred tax assets: Deferred fee income $ 187 189 Deferred compensation expense 2,893 3,717 Bad debts 18,823 19,478 Other reserves 1,823 — Accrued postretirement benefit cost 641 644 Stock benefit plans 1,085 1,626 Writedown of investment securities 2,875 2,994 Accrued expenses 348 228 Pension and postretirement benefits 18,491 16,035 Unrealized loss on the fair value of derivatives 958 1,496 Purchase accounting 1,215 2,236 Other 153 325 Total deferred tax assets 49,492 48,968 Deferred tax liabilities: Pension expense 8,689 7,557 Unrealized gain on the fair value of securities available-for-sale 252 2,122 Intangible assets 21,927 23,003 Mortgage servicing rights 1,559 120 Fixed assets 8,107 8,731 Other 635 460 Total deferred tax liabilities 41,169 41,993 Net deferred tax asset $ 8,323 6,975

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2016
Earnings Per Share [Abstract]
Schedule of computation of basic and diluted earnings per share	The computation of basic and diluted earnings per share for the years ended December 31, 2016 , 2015 and 2014 follows: Years ended December 31, 2016 2015 2014 Net income available to common shareholders $ 49,667 60,540 61,962 Weighted average common shares outstanding 99,439,174 94,314,420 91,535,298 Dilutive potential shares due to effect of stock options 1,225,514 515,369 739,699 Total weighted average common shares and dilutive potential shares 100,664,688 94,829,789 92,274,997 Basic earnings per share (1) $ 0.50 0.64 0.68 Diluted earnings per share (1) $ 0.49 0.64 0.67 (1) Not in thousands.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2016
Stock options
Employee benefit plans
Schedule of activity under option plans	The following table summarizes the activity in our option plans during the years ended December 31, 2016 , 2015 and 2014 (amounts in this table are not in thousands): Years ended December 31, 2016 2015 2014 Number Weighted average exercise price Number Weighted average exercise price Number Weighted average exercise price Balance at beginning of year 6,306,496 $ 11.81 6,402,407 $ 11.65 6,816,294 $ 11.46 Granted (1) 725,400 14.15 665,370 12.37 592,550 13.15 Exercised (2) (1,081,072 ) 11.01 (474,253 ) 10.27 (745,419 ) 10.86 Forfeited/ expired (146,719 ) 12.71 (287,028 ) 12.26 (261,018 ) 11.71 Balance at end of year 5,804,105 $ 12.25 6,306,496 $ 11.81 6,402,407 $ 11.65 Exercisable at end of year 3,035,718 $ 11.71 3,431,113 $ 11.42 3,333,942 $ 11.20 (1) Weighted average fair value of options at grant date: $1.52 , $1.14 and $1.45 , respectively. (2) The total intrinsic value of options exercised was $5.1 million , $1.2 million and $2.3 million , respectively.
Schedule of number of options outstanding, number of options exercisable, and weighted average remaining life of all option grants	The following table summarizes the number of options outstanding, number of options exercisable, and weighted average remaining life of all option grants as of December 31, 2016 : Exercise Exercise Exercise Exercise Exercise Exercise Exercise Options outstanding: Number of options 195,902 207,156 125,448 320,045 47,557 432,941 398,478 Weighted average remaining contract life (years) 2.25 2.00 1.25 3.25 0.25 5.50 4.25 Options exercisable: Number of options 195,902 207,156 125,448 298,473 47,557 226,915 309,987 Weighted average remaining term - vested (years) 2.25 2.00 1.25 3.25 0.25 5.50 4.25 Exercise Exercise Exercise Exercise Exercise Exercise Total Options outstanding: Number of options 21,500 1,815,615 577,405 474,467 487,865 699,726 5,804,105 Weighted average remaining contract life (years) 4.50 4.50 8.50 6.50 7.50 9.50 5.59 Options exercisable: Number of options 12,931 1,151,004 81,759 199,534 132,186 46,866 3,035,718 Weighted average remaining term - vested (years) 4.50 4.50 8.50 6.50 7.50 9.50 4.05
Pension Plans
Employee benefit plans
Schedule of other changes in the defined benefit pension plans' plan assets and benefit obligations recognized in other comprehensive income	The following table sets forth other changes in the defined benefit pension plans’ plan assets and benefit obligations recognized in other comprehensive income: Years ended December 31, 2016 2015 2014 Net loss/ (gain) $ 1,550 (420 ) 30,779 Prior service cost/ (credit) — — — Amortization of prior service cost 2,323 2,323 2,322 Total recognized in other comprehensive income $ 3,873 1,903 33,101 Total recognized in net periodic pension cost and other comprehensive income/ (loss) $ 7,641 4,753 32,506
Schedule of defined benefit pension plans' funded status	The following table sets forth information for the defined benefit pension plans’ funded status at December 31, 2016 and 2015 : December 31, 2016 2015 Change in benefit obligation: Benefit obligation at beginning of year $ 162,133 159,587 Service cost 5,496 5,721 Interest cost 6,781 6,125 Acquisition — 5,662 Actuarial (gain)/ loss 4,267 (9,357 ) Benefits paid (6,469 ) (5,605 ) Benefit obligation at end of year $ 172,208 162,133 Change in plan assets: Fair value of plan assets at beginning of year 143,655 140,183 Actual return on plan assets 8,903 (2,264 ) Employer contributions 6,536 6,460 Acquisition — 4,881 Benefits paid (6,469 ) (5,605 ) Fair value of plan assets at end of period $ 152,625 143,655 Funded status at end of year $ (19,583 ) (18,478 )
Schedule of assumptions used to develop the net periodic pension cost	The following table sets forth the assumptions used to develop the net periodic pension cost: Years ended December 31, 2016 2015 2014 Discount rate 4.25 % 3.89 % 4.86 % Expected long-term rate of return on assets 7.00 % 7.50 % 7.50 % Rate of increase in compensation levels 3.00 % 3.00 % 3.00 %
Schedule of assumptions used to determine benefit obligations	The following table sets forth the assumptions used to determine benefit obligations at the end of each period: Years ended December 31, 2016 2015 2014 Discount rate 4.06 % 4.25 % 3.89 % Expected long-term rate of return on assets 7.00 % 7.00 % 7.50 % Rate of increase in compensation levels 3.00 % 3.00 % 3.00 %
Schedule of certain information related to pension plans	The following table sets forth certain information related to our pension plans: December 31, 2016 2015 Projected benefit obligation $ 172,208 162,133 Accumulated benefit obligation 172,208 162,133 Fair value of plan assets 152,625 143,655
Schedule of weighted average asset allocation of defined benefit plans	The following table sets forth the weighted average asset allocation of defined benefit plans: Target December 31, Allocation 2016 2015 Debt securities 20 – 50% 23 % 20 % Equity securities 30 – 60% 72 % 69 % Other 5 – 50% 5 % 11 % Total 100 % 100 %
Schedule of allocation of plan assets	The following table sets forth the pension plan assets as of December 31, 2016 and 2015 : December 31, 2016 2015 Mutual funds — debt $ 35,224 28,316 Mutual funds — equity 110,078 98,517 Cash and cash equivalents 7,322 16,822
Postretirement Healthcare Plan
Employee benefit plans
Schedule of net periodic costs for the defined benefit pension plans and the post retirement healthcare plans	The following table sets forth the net periodic benefit cost for the postretirement healthcare benefits plan for the years ended December 31, 2016 , 2015 and 2014 : Years ended December 31, 2016 2015 2014 Service cost $ — — — Interest cost 70 58 65 Amortization of net loss 90 60 48 Net period benefit cost $ 160 118 113 The following table sets forth the net periodic pension cost for the defined benefit pension plans for the years ended December 31, 2016 , 2015 and 2014 : Years ended December 31, 2016 2015 2014 Service cost $ 5,496 5,721 4,138 Interest cost 6,781 6,125 5,827 Expected return on plan assets (9,897 ) (10,371 ) (9,663 ) Net amortization and deferral 1,388 1,375 (897 ) Net periodic pension (benefit)/ cost $ 3,768 2,850 (595 )
Schedule of other changes in the defined benefit pension plans' plan assets and benefit obligations recognized in other comprehensive income	The following table sets forth other changes in the postretirement healthcare plan’s plan assets and benefit obligations recognized in other comprehensive income: Years ended December 31, 2016 2015 2014 Net loss/ (gain) $ 109 273 195 Total recognized in other comprehensive income $ 109 273 195 Total recognized in net periodic benefit cost and other comprehensive income $ 270 391 308
Schedule of defined benefit pension plans' funded status	The following table sets forth the funded status of the postretirement healthcare benefit plan at December 31, 2016 and 2015 : December 31, 2016 2015 Change in benefit obligation: Benefit obligation at beginning of year $ 1,737 1,565 Service cost — — Interest cost 70 58 Actuarial loss 200 333 Benefits paid (228 ) (219 ) Benefit obligation at end of year $ 1,779 1,737 Change in plan assets: Fair value of plan assets at beginning of year — — Employer contributions 228 219 Benefits paid (228 ) (219 ) Fair value of plan assets at end of year $ — — Funded status at year end $ (1,779 ) (1,737 )
Schedule of assumptions used to develop the net periodic pension cost	The assumptions used to develop the preceding information for postretirement healthcare benefits are as follows: Years ended December 31, 2016 2015 2014 Discount rate 4.25 % 3.89 % 4.86 % Monthly cost of healthcare insurance per beneficiary (1) $ 539 470 384 Annual rate of increase in healthcare costs 4.00 % 4.00 % 4.00 % (1) Not in thousands
Schedule of accumulated benefit obligation in excess of plan assets	The following table sets forth information for plans with an accumulated benefit obligation in excess of plan assets: December 31, 2016 2015 Projected benefit obligation $ 1,779 1,737 Accumulated benefit obligation 1,779 1,737 Fair value of plan assets — —

Disclosures About Fair Value 48

Disclosures About Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2016
Fair Value Disclosures [Abstract]
Schedule of the carrying amount and estimated fair value of the entity's financial instruments included in the consolidated statement of financial condition	The following table sets forth the carrying amount and estimated fair value of our financial instruments included in the consolidated statement of financial condition at December 31, 2016 and 2015 : December 31, 2016 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 389,867 389,867 389,867 — — Securities available-for-sale 826,200 826,200 4,440 812,394 9,366 Securities held-to-maturity 19,978 20,426 — 20,426 — Loans receivable, net 7,496,408 7,878,815 9,625 — 7,869,190 Accrued interest receivable 21,699 21,699 21,699 — — FHLB Stock 7,390 7,390 — — — Total financial assets $ 8,761,542 9,144,397 425,631 832,820 7,878,556 Financial liabilities: Savings and checking accounts $ 6,341,735 6,341,735 6,341,735 — — Time deposits 1,540,586 1,626,434 — — 1,626,434 Borrowed funds 142,899 142,899 142,899 — — Junior subordinated debentures 111,213 113,313 — — 113,313 Cash flow hedges - swaps 2,736 2,736 — 2,736 — Accrued interest payable 643 643 643 — — Total financial liabilities $ 8,139,812 8,227,760 6,485,277 2,736 1,739,747 December 31, 2015 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 167,408 167,408 167,408 — — Securities available-for-sale 874,405 874,405 1,894 863,556 8,955 Securities held-to-maturity 31,689 32,552 — 32,552 — Loans receivable, net 7,159,449 7,482,431 — — 7,482,431 Accrued interest receivable 21,072 21,072 21,072 — — FHLB Stock 40,903 40,903 — — — Total financial assets $ 8,294,926 8,618,771 190,374 896,108 7,491,386 Financial liabilities: Savings and checking accounts $ 4,917,863 4,917,863 4,917,863 — — Time deposits 1,694,718 1,710,388 — — 1,710,388 Borrowed funds 975,007 998,527 118,664 — 879,863 Junior subordinated debentures 111,213 115,268 — — 115,268 Cash flow hedges - swaps 4,276 4,276 — 4,276 — Accrued interest payable 1,993 1,993 1,993 — — Total financial liabilities $ 7,705,070 7,748,315 5,038,520 4,276 2,705,519
Schedule of assets and liabilities measured at fair value on a recurring basis	The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2016 : Level 1 Level 2 Level 3 Total at fair value Equity securities $ 4,440 — — 4,440 Debt securities: U.S. government and agencies — 6 — 6 Government sponsored enterprises — 294,170 — 294,170 States and political subdivisions — 63,070 — 63,070 Corporate — 7,614 9,366 16,980 Total debt securities — 364,860 9,366 374,226 Residential mortgage-backed securities: GNMA — 30,883 — 30,883 FNMA — 106,578 — 106,578 FHLMC — 82,115 — 82,115 Non-agency — 579 — 579 Collateralized mortgage obligations: GNMA — 6,287 — 6,287 FNMA — 95,186 — 95,186 FHLMC — 119,197 — 119,197 SBA — 6,608 — 6,608 Non-agency — 101 — 101 Total mortgage-backed securities — 447,534 — 447,534 Interest rate swaps — (2,736 ) — (2,736 ) Total assets and liabilities $ 4,440 809,658 9,366 823,464 The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2015 : Level 1 Level 2 Level 3 Total at fair value Equity securities $ 1,894 — — 1,894 Debt securities: U.S. government and agencies — 11 — 11 Government sponsored enterprises — 294,440 — 294,440 States and political subdivisions — 82,868 — 82,868 Corporate — 7,520 8,955 16,475 Total debt securities — 384,839 8,955 393,794 Residential mortgage-backed securities: GNMA — 27,082 — 27,082 FNMA — 99,170 — 99,170 FHLMC — 50,369 — 50,369 Non-agency — 606 — 606 Collateralized mortgage obligations: GNMA — 10,669 — 10,669 FNMA — 122,528 — 122,528 FHLMC — 157,378 — 157,378 SBA — 8,166 — 8,166 Non-agency — 2,749 — 2,749 Total mortgage-backed securities — 478,717 — 478,717 Interest rate swaps — (4,276 ) — (4,276 ) Total assets and liabilities $ 1,894 859,280 8,955 870,129
Schedule of reconciliation of debt securities measured at fair value on a recurring basis using significant unobservable inputs (Level 3)	The table below presents a reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3) for the year ended December 31, 2016 and 2015 : December 31, 2016 2015 Debt securities Beginning balance January 1, $ 8,955 10,597 Total net realized investment gains/ (losses) and net change in unrealized appreciation/ (depreciation): Included in net income as OTTI — — Included in other comprehensive income 411 (502 ) Purchases — — Sales/ calls — (1,140 ) Transfers into Level 3 — — Transfers out of Level 3 — — Ending balance December 31, $ 9,366 8,955
Schedule of fair value measurement for nonrecurring assets	The following table represents the fair market measurement for only those nonrecurring assets that had a fair market value below the carrying amount as of December 31, 2016 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 41,933 41,933 Mortgage servicing rights — — 246 246 Real estate owned — — 4,889 4,889 Total assets $ — — 47,068 47,068 The following table represents the fair market measurement for only those nonrecurring assets that had a fair market value below the carrying amount as of December 31, 2015 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 48,181 48,181 Real estate owned — — 8,725 8,725 Total assets $ — — 56,906 56,906
Schedule of quantitative information about assets measured at fair value on a recurring and nonrecurring basis for Level 3 Fair Value Measurements	The following table presents additional quantitative information about assets measured at fair value on a recurring and nonrecurring basis and for which we have utilized Level 3 inputs to determine fair value at December 31, 2016 : Fair value Valuation techniques Significant unobservable inputs Range (weighted average) Debt securities $ 9,366 Discounted cash Discount margin 0.4% to 2.1% (0.7)% flow Default rates 1.00% Prepayment speeds 1.00% annually Loans measured for impairment 41,933 Appraisal Estimated costs to sell 10% value (1) Discounted cash Discount rate 3.8% to 20.0% (11.0%) flow Mortgage servicing rights 246 Discounted cash Annual service cost 80 flow Prepayment rate 6.0% to 7.4% (7.1%) Expected life (months) 66.2 to 70.9 (68.9) Option adjusted spread 800 basis points Forward yield curve 0.6% to 2.2% (1.3%) Real estate owned 4,889 Appraisal Estimated costs to sell 10% value (1) (1) Fair value is generally determined through independent appraisals of the underlying collateral, which may include Level 3 inputs that are not identifiable, or by using the discounted cash flow method if the loan is not collateral dependent.

Regulatory Capital Requiremen49

Regulatory Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2016
Regulatory Capital Requirements [Abstract]
Schedule of actual, required, and well capitalized levels	The actual, required, and well capitalized levels as of December 31, 2016 and 2015 were as follows: At December 31, 2016 Minimum capital Well capitalized Actual requirements (1) requirements (1) Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,051,582 14.873 % 609,835 8.625 % 751,246 10.625 % Northwest Bank 961,279 13.609 % 609,248 8.625 % 750,523 10.625 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 990,153 14.004 % 468,424 6.625 % 609,835 8.625 % Northwest Bank 900,328 12.746 % 467,973 6.625 % 609,248 8.625 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 882,278 12.478 % 362,366 5.125 % 503,777 7.125 % Northwest Bank 900,328 12.746 % 362,017 5.125 % 503,292 7.125 % Tier 1 capital (leverage) (to average assets) Northwest Bancshares, Inc. 990,153 10.530 % 376,116 4.000 % 470,145 5.000 % Northwest Bank 900,328 9.585 % 375,735 4.000 % 469,669 5.000 % (1) Amounts and ratios include the 2016 capital conservation buffer of 0.625% with the exception of Tier 1 capital to average assets. At December 31, 2015 Minimum capital Well capitalized Actual requirements requirements (1) Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,102,468 16.63 % 530,257 8.00 % 662,821 10.00 % Northwest Bank 1,006,230 15.20 % 529,498 8.00 % 661,872 10.00 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,039,574 15.68 % 397,693 6.00 % 530,257 8.00 % Northwest Bank 943,554 14.26 % 397,123 6.00 % 529,498 8.00 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 931,699 14.06 % 298,269 4.50 % 430,834 6.50 % Northwest Bank 943,554 14.26 % 297,843 4.50 % 430,217 6.50 % Tier I capital (leverage) (to average assets) Northwest Bancshares, Inc. 1,039,574 11.96 % 347,582 4.00 % 434,477 5.00 % Northwest Bank 943,554 10.87 % 347,063 4.00 % 433,829 5.00 %

Components of Accumulated Oth50

Components of Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Schedule of the components of accumulated other comprehensive income	The following table sets forth the components of accumulated other comprehensive income as of December 31, 2016 and 2015 : December 31, 2016 2015 Unrealized gain on marketable securities available-for-sale $ 395 3,325 Fair value of interest rate swaps (1,778 ) (2,779 ) Defined benefit pension plans (26,608 ) (25,081 ) Accumulated other comprehensive income $ (27,991 ) (24,535 )
Schedule of the changes in accumulated other comprehensive income by component	The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2016 : Unrealized gains and losses on securities available-for- sale Change in fair value of interest rate swaps Change in defined benefit pension plans Total Balance as of January 1, $ 3,325 (2,779 ) (25,081 ) (24,535 ) Other comprehensive income/ (loss) before reclassification adjustments (2,728 ) 1,001 (2,399 ) (4,126 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (202 ) — 872 670 Net other comprehensive income/ (loss) (2,930 ) 1,001 (1,527 ) (3,456 ) Balance as of December 31, $ 395 (1,778 ) (26,608 ) (27,991 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $331 , net of tax (income tax expense) of $(129) . (2) Consists of amortization of prior service cost (compensation and employee benefits) of $2,323 and amortization of net loss (compensation and employee benefits) of $(3,801) , net of tax (income tax expense) of $606 . See note 15. The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2015 : Unrealized gains and losses on securities available-for- sale Change in fair value of interest rate swaps Change in defined benefit pension plans Total Balance as of January 1, $ 3,461 (4,078 ) (23,753 ) (24,370 ) Other comprehensive income/ (loss) before reclassification adjustments 315 1,299 (2,203 ) (589 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (451 ) — 875 424 Net other comprehensive income/ (loss) (136 ) 1,299 (1,328 ) (165 ) Balance as of December 31, $ 3,325 (2,779 ) (25,081 ) (24,535 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $740 net of tax (income tax expense) of $(289) . (2) Consists of amortization of prior service cost (compensation and employee benefits) of $2,323 and amortization of net loss (compensation and employee benefits) of $(3,758) , net of tax (income tax expense) of $560 . See note 15. The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2014 : Unrealized gains and losses on securities available-for- sale Change in fair value of interest rate swaps Change in defined benefit pension plans Total Balance as of January 1, $ (3,233 ) (5,224 ) (3,443 ) (11,900 ) Other comprehensive income/ (loss) before reclassification adjustments 9,042 1,146 (19,758 ) (9,604 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (2,348 ) — (552 ) (2,866 ) Net other comprehensive income/ (loss) 6,694 1,146 (20,310 ) (12,470 ) Balance as of December 31, $ 3,461 (4,078 ) (23,753 ) (24,370 ) (1) Consists of realized losses on securities (gain on sales of investments, net) of 3,849 net of tax (income tax expense) of $(1,501) . (2) Consists of amortization of prior service cost (compensation and employee benefits) of $2,323 and amortization of net loss (compensation and employee benefits) of $(1,436) , net of tax (income tax expense) of $(335) . See note 15.

Parent Company Only Financial51

Parent Company Only Financial Statements - Condensed (Tables)	12 Months Ended
	Dec. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Schedule of statements of financial condition	December 31, 2016 2015 Assets Cash and cash equivalents $ 34,521 91,056 Marketable securities available-for-sale 4,413 1,884 Investment in bank subsidiary 1,193,175 1,182,308 Other assets 52,645 3,547 Total assets $ 1,284,754 1,278,795 Liabilities and Shareholders’ Equity Liabilities: Debentures payable $ 111,213 111,213 Other liabilities 2,878 4,419 Total liabilities 114,091 115,632 Shareholders’ equity 1,170,663 1,163,163 Total liabilities and shareholders’ equity $ 1,284,754 1,278,795
Schedule of statements of income	Years ended December 31, 2016 2015 2014 Income: Interest income $ 737 1,258 1,248 Other income 709 659 3,424 Dividends from bank subsidiary 50,000 135,000 66,183 Undistributed earnings from equity investment in bank subsidiary 2,760 (70,854 ) (3,261 ) Total income 54,206 66,063 67,594 Expense: Compensation and benefits 1,129 1,061 962 Other expense 561 1,356 572 Interest expense 4,560 4,926 4,691 Total expense 6,250 7,343 6,225 Income before income taxes 47,956 58,720 61,369 Federal and state income taxes (1,711 ) (1,820 ) (593 ) Net income $ 49,667 60,540 61,962
Schedule of statements of cash flows	Years ended December 31, 2016 2015 2014 Operating activities: Net income $ 49,667 60,540 61,962 Adjustments to reconcile net income to net cash provided by operating activities: Undistributed earnings of subsidiary (2,760 ) 70,854 3,261 Noncash stock benefit plan compensation expense 10,916 5,654 5,714 Gain on sale of marketable securities (43 ) (54 ) (2,768 ) Net change in other assets and liabilities (63,533 ) (5,824 ) (2,352 ) Net cash provided by/ (used in) operating activities (5,753 ) 131,170 65,817 Investing activities: Net sale of marketable securities (1,952 ) 1,192 2,658 Acquisition, net of cash received — (89,398 ) — Net cash provided by/ (used in) investing activities (1,952 ) (88,206 ) 2,658 Financing activities: Cash dividends paid (60,156 ) (52,825 ) (149,932 ) Share repurchases (1,752 ) (7,847 ) (5,273 ) Repayment of loan to ESOP 797 1,549 1,190 Redemption of junior subordinated debt — (8,119 ) — Excess tax benefit from stock-based compensation 1,425 332 945 Proceeds from options exercised 10,856 4,303 6,519 Net cash used in financing activities (48,830 ) (62,607 ) (146,551 ) Net decrease in cash and cash equivalents $ (56,535 ) (19,643 ) (78,076 ) Cash and cash equivalents at beginning of year 91,056 110,699 188,775 Net decrease in cash and cash equivalents (56,535 ) (19,643 ) (78,076 ) Cash and cash equivalents at end of year $ 34,521 91,056 110,699

Business Segments (Tables)

Business Segments (Tables)	12 Months Ended
	Dec. 31, 2016
Segment Reporting [Abstract]
Schedule of financial information for reportable segments	The following tables provide financial information for these segments. The All Other column represents the parent company, other nonbank subsidiaries, and elimination entries necessary to reconcile to the consolidated amounts presented in the financial statements. At or for the year ended Community Banking Consumer Finance All Other (1) Consolidated External interest income $ 327,855 17,064 715 345,634 Intersegment interest income 2,564 — (2,564 ) — Interest expense 33,883 2,564 1,852 38,299 Provision for loan losses 9,846 3,696 — 13,542 Noninterest income 83,631 1,597 132 85,360 Noninterest expense 295,023 11,579 1,236 307,838 Income tax expense/ (benefit) 23,023 336 (1,711 ) 21,648 Net income $ 52,275 486 (3,094 ) 49,667 Total assets $ 9,500,419 109,744 13,477 9,623,640 At or for the year ended Community Banking Consumer Finance All Other (1) Consolidated External interest income $ 300,746 17,978 856 319,580 Intersegment interest income 2,393 — (2,393 ) — Interest expense 51,895 2,393 2,039 56,327 Provision for loan losses 7,429 2,283 — 9,712 Noninterest income 67,167 1,555 114 68,836 Noninterest expense 219,793 12,120 1,964 233,877 Income tax expense 28,642 1,138 (1,820 ) 27,960 Net income $ 62,547 1,599 (3,606 ) 60,540 Total assets $ 8,827,574 110,670 13,655 8,951,899 At or for the year ended Community Banking Consumer Finance All Other (1) Consolidated External interest income $ 285,635 18,789 1,003 305,427 Intersegment interest income 2,406 — (2,406 ) — Interest expense 52,291 2,406 1,890 56,587 Provision for loan losses 17,500 2,814 — 20,314 Noninterest income 66,431 1,517 2,818 70,766 Noninterest expense 202,489 11,968 1,078 215,535 Income tax expense/ (benefit) 21,097 1,291 (593 ) 21,795 Net income $ 61,095 1,827 (960 ) 61,962 Total assets $ 7,650,665 107,216 17,152 7,775,033 (1) Eliminations consist of intercompany interest income and interest expense.

Guaranteed Preferred Benefici53

Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements (Tables)	12 Months Ended
	Dec. 31, 2016
Guaranteed Preferred Beneficial Interests in Company's Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements
Schedule of liability derivatives included in other liabilities	December 31, Liability Derivatives (Included in Other Liabilities) 2016 2015 Cash flow hedges — swaps: Fair value $ 2,736 4,276 Notional amount 50,000 50,000 Collateral posted 3,005 4,705
Summary of guaranteed capital debt securities and junior subordinated deferrable interest debentures held by the trusts	The following table sets forth a summary of guaranteed capital debt securities and junior subordinated deferrable interest debentures held by the trusts as of December 31, 2016 and 2015 : Capital Debt December 31, Securities 2016 2015 Northwest Bancorp Capital Trust III $ 50,000 51,547 51,547 Northwest Bancorp Statutory Trust IV 50,000 51,547 51,547 LNB Trust II 7,875 8,119 8,119 Total $ 107,875 111,213 111,213

Selected Quarterly Financial 54

Selected Quarterly Financial Data - Unaudited (Tables)	12 Months Ended
	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Schedule of selected quarterly financial data	Quarters ended March 31 June 30 (1) September 30 (1) December 31 (In thousands, except per share data) 2016: Interest income $ 85,298 85,555 84,748 90,033 Interest expense 13,746 10,008 7,454 7,091 Net interest income 71,552 75,547 77,294 82,942 Provision for loan losses 1,660 4,199 5,538 2,145 Noninterest income 19,448 20,275 20,818 24,819 Noninterest expenses 63,275 102,122 73,680 68,761 Income before income taxes 26,065 (10,499 ) 18,894 36,855 Income tax expense 8,081 (3,491 ) 4,697 12,361 Net income $ 17,984 (7,008 ) 14,197 24,494 Basic earnings per share $ 0.18 (0.07 ) 0.14 0.24 Diluted earnings per share $ 0.18 (0.07 ) 0.14 0.24 (1) During the quarters ended June 30, 2016 and September 30, 2016, the Company recorded immaterial error corrections of approximately $1.1 million and $1.4 million , respectively, reclassifying amortization of broker fees paid for mortgage loans to interest income from compensation expense. The correction reduced both interest income and compensation expense but had no impact on net income. Quarters ended March 31 June 30 September 30 December 31 (In thousands, except per share data) 2015: Interest income $ 76,880 75,970 81,091 85,639 Interest expense 13,899 13,792 14,150 14,486 Net interest income 62,981 62,178 66,941 71,153 Provision for loan losses 900 1,050 3,167 4,595 Noninterest income 14,625 16,525 18,140 19,546 Noninterest expenses 53,711 55,135 63,804 61,227 Income before income taxes 22,995 22,518 18,110 24,877 Income tax expense 6,825 7,213 5,238 8,684 Net income $ 16,170 15,305 12,872 16,193 Basic earnings per share $ 0.18 0.17 0.14 0.16 Diluted earnings per share $ 0.18 0.17 0.13 0.16 Quarters ended March 31 June 30 September 30 December 31 (In thousands, except per share data) 2014: Interest income $ 75,326 76,987 76,528 76,586 Interest expense 14,204 14,214 14,187 13,982 Net interest income 61,122 62,773 62,341 62,604 Provision for loan losses 7,485 8,285 3,466 1,078 Noninterest income 19,381 16,427 17,737 17,221 Noninterest expenses 53,163 53,806 53,354 55,212 Income before income taxes 19,855 17,109 23,258 23,535 Income tax expense 5,244 4,435 5,926 6,190 Net income $ 14,611 12,674 17,332 17,345 Basic earnings per share $ 0.16 0.14 0.19 0.19 Diluted earnings per share $ 0.16 0.14 0.19 0.19

Subsequent Events - Unaudited -

Subsequent Events - Unaudited - (Tables)	12 Months Ended
	Dec. 31, 2016
Subsequent Events [Abstract]
Assets and Liabilities, Held-for Sale	The following table provides information related to assets and liabilities held-for-sale at December 31, 2016 : Balance at December 31, 2016 Assets held-for-sale: Residential mortgage loans $ 26,406 Home equity loans 15,725 Consumer loans 522 Commercial real estate loans 101,123 Commercial loans 2,884 Total loans 146,660 Accrued interest receivable 416 Premises and equipment, net 5,452 Total assets held-for-sale $ 152,528 Liabilities held-for-sale: Noninterest-bearing demand deposits $ 34,657 Interest-bearing demand deposits 17,181 Money market deposit accounts 45,806 Savings deposits 55,205 Time deposits 62,800 Total deposits 215,649 Accrued interest payable 8 Total liabilities held-for-sale $ 215,657

Summary of Significant Accoun56

Summary of Significant Accounting Policies - Loans Receivable and Allowance for Loan Losses and Other Narrative Information (Details)	12 Months Ended
	Dec. 31, 2016USD ($)officebank	Dec. 31, 2015USD ($)
Nature of Operations
Number of banking locations | bank	176
Number of consumer finance offices | office	49
Investment Securities
Securities classified as trading	$ 0	$ 0
Loans Receivable
Number of days in delinquency for accrued interest on loans to be considered for reversal, minimum	90 days
Number of days delinquent for loans to be placed on non-accrual status, minimum	90 days
Period of time to return TDRs included in impaired loans to performing status through the fulfilling of contractual terms	6 months
Allowance for Loan Losses and Provision for Loan Losses
Number of days for loans not deemed to be impaired	30 days
Residential mortgage loans classified as held-for-sale	$ 36,000,000	$ 0
Commercial Banking
Allowance for Loan Losses and Provision for Loan Losses
Financing receivable, individually evaluated for impairment, threshold amount for analysis	$ 1,000,000
Actual losses incurred through average number of rolling years	3 years
Personal Banking
Allowance for Loan Losses and Provision for Loan Losses
Actual losses incurred through average number of rolling years	3 years
Number of days delinquent for allowance for loans	90 days
Number of days delinquent for loans to be charged off or charged down unless that borrower has filed for bankruptcy	180 days

Summary of Significant Accoun57

Summary of Significant Accounting Policies - Premises and Equipment and Goodwill (Details)	12 Months Ended
	Dec. 31, 2016valuation_method
Goodwill
Number of valuation methodologies for impairment of goodwill	4
Minimum
Premises and Equipment
Estimated lives	3 years
Core Deposit Intangibles
Useful life of core deposit intangibles	7 years
Maximum
Premises and Equipment
Estimated lives	39 years
Core Deposit Intangibles
Useful life of core deposit intangibles	11 years

Summary of Significant Accoun58

Summary of Significant Accounting Policies - Stock Related Compensation and Segments (Details) $ in Millions	Sep. 30, 2016shares	May 18, 2016shares	May 17, 2016shares	May 20, 2015shares	May 19, 2015shares	May 21, 2014shares	Dec. 31, 2016USD ($)segmentshares	Dec. 31, 2015USD ($)shares	Dec. 31, 2014USD ($)shares
Weighted average assumptions
Employee Stock Ownership Plan (ESOP), number of unallocated shares distributed to employees (in shares)	401,356
Employee Stock Ownership Plan (ESOP), compensation expense | $							$ 6.3
Segment Reporting
Number of reportable segments | segment							2
Stock options
Stock Related Compensation
Number of shares awarded							725,400	665,370	592,550
Vesting period							10 years
Stock-based aggregate disclosure
Compensation expense for unvested common share awards which is yet to be recognized | $							$ 4.1
Weighted average period over which stock option expense will be recognized							4 years 18 days
Weighted average assumptions
Expected volatility, minimum (as a percent)							17.00%
Expected volatility, maximum (as a percent)							22.00%
Risk-free interest rates, minimum (as a percent)							1.70%
Risk-free interest rates, maximum (as a percent)							3.10%
Employee Stock Ownership Plan (ESOP), number of shares retired (in shares)	1,366,574
Stock options | Minimum
Weighted average assumptions
Dividend yields (as a percent)							3.20%
Expected lives							7 years
Stock options | Maximum
Weighted average assumptions
Dividend yields (as a percent)							5.10%
Expected lives							9 years
Stock options | Employees
Stock Related Compensation
Number of shares awarded			660,600		660,570	534,950	660,600
Stock options | Director
Stock Related Compensation
Number of shares awarded			64,800		64,800	57,600	64,800
Restricted common shares
Stock Related Compensation
Vesting period							10 years
Stock-based aggregate disclosure
Stock-based employee compensation expense | $							$ 3.5	$ 3	$ 3
Effect of compensation expense on net income included in income before income taxes | $							$ 2.2	$ 1.8	$ 1.8
Restricted common shares | Employees
Stock Related Compensation
Number of shares awarded		310,160		282,050		251,030	310,160
Restricted common shares | Director
Stock Related Compensation
Number of shares awarded		24,300		24,300		21,600	24,300

Acquisition (Details)

Acquisition (Details) - Northwest Bank - First Niagara Bank, National Association and First Niagara Securities, Inc. $ in Thousands	Sep. 09, 2016USD ($)branch	Dec. 31, 2016USD ($)
Business Acquisition [Line Items]
Number of branch locations acquired | branch	18
Assets under management, carrying amount	$ 450,000
Deposit premium paid	76,500
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value
Cash and cash equivalents	1,103,372
Loans	455,857
Other assets	16,978
Total assets acquired	1,603,082
Deposits	(1,642,846)
Other liabilities	(5,403)
Total liabilities assumed	(1,648,249)
Goodwill	(45,167)
Business combination, acquisition costs expensed		$ 9,200
Core Deposits
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value
Core deposit intangible	$ 25,732
Useful life of core deposit intangibles	11 years
Customer Relationships
Recognized amounts of identifiable assets acquired and (liabilities assumed), at fair value
Core deposit intangible	$ 1,143
Useful life of core deposit intangibles	7 years

Marketable Securities - Availab

Marketable Securities - Available For Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Amortized cost
Marketable securities available-for-sale, amortized cost	$ 825,552	$ 868,956
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	9,862	11,733
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(9,214)	(6,284)
Fair value
Marketable securities available-for-sale, total fair value	826,200	874,405
U.S. Government and agencies
Amortized cost
Due in one year or less	6	11
Gross unrealized holding gains
Due in one year or less	0	0
Gross unrealized holding losses
Due in one year or less	0	0
Fair value
Due in one year or less	6	11
Government sponsored enterprises
Amortized cost
Due in one year or less	74,980	15,500
Due after one year through five years	220,937	257,463
Due after five years through ten years	585	12,721
Due after ten years	0	9,815
Gross unrealized holding gains
Due in one year or less	5	3
Due after one year through five years	203	298
Due after five years through ten years	0	14
Due after ten years	0	135
Gross unrealized holding losses
Due in one year or less	(33)	(48)
Due after one year through five years	(2,504)	(1,395)
Due after five years through ten years	(3)	(23)
Due after ten years	0	(43)
Fair value
Due in one year or less	74,952	15,455
Due after one year through five years	218,636	256,366
Due after five years through ten years	582	12,712
Due after ten years	0	9,907
Equity securities
Amortized cost
Marketable securities available-for-sale, amortized cost	3,351	1,400
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	1,095	500
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(6)	(6)
Fair value
Marketable securities available-for-sale, total fair value	4,440	1,894
Municipal securities
Amortized cost
Due in one year or less	2,449	1,684
Due after one year through five years	9,448	14,327
Due after five years through ten years	11,794	12,400
Due after ten years	38,141	52,286
Gross unrealized holding gains
Due in one year or less	7	8
Due after one year through five years	105	117
Due after five years through ten years	137	323
Due after ten years	1,027	1,727
Gross unrealized holding losses
Due in one year or less	0	0
Due after one year through five years	(21)	(4)
Due after five years through ten years	(1)	0
Due after ten years	(16)	0
Fair value
Due in one year or less	2,456	1,692
Due after one year through five years	9,532	14,440
Due after five years through ten years	11,930	12,723
Due after ten years	39,152	54,013
Corporate debt issues
Amortized cost
Due after ten years	14,367	14,463
Gross unrealized holding gains
Due after ten years	2,935	2,417
Gross unrealized holding losses
Due after ten years	(322)	(405)
Fair value
Due after ten years	16,980	16,475
Residential mortgage-backed securities
Amortized cost
Marketable securities available-for-sale, amortized cost	449,494	476,886
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	4,348	6,191
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(6,308)	(4,360)
Fair value
Marketable securities available-for-sale, total fair value	447,534	478,717
Fixed rate | Pass-through
Amortized cost
Marketable securities available-for-sale, amortized cost	175,398	118,266
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	1,849	2,480
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(2,680)	(420)
Fair value
Marketable securities available-for-sale, total fair value	174,567	120,326
Fixed rate | Non-agency CMOs
Amortized cost
Marketable securities available-for-sale, amortized cost	100	2,519
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	1	230
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	0	0
Fair value
Marketable securities available-for-sale, total fair value	101	2,749
Fixed rate | Agency CMOs
Amortized cost
Marketable securities available-for-sale, amortized cost	165,535	215,719
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	185	389
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(3,455)	(3,881)
Fair value
Marketable securities available-for-sale, total fair value	162,265	212,227
Variable rate | Pass-through
Amortized cost
Marketable securities available-for-sale, amortized cost	43,587	54,292
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	2,007	2,616
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(6)	(7)
Fair value
Marketable securities available-for-sale, total fair value	45,588	56,901
Variable rate | Agency CMOs
Amortized cost
Marketable securities available-for-sale, amortized cost	64,874	86,090
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	306	476
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(167)	(52)
Fair value
Marketable securities available-for-sale, total fair value	$ 65,013	$ 86,514

Marketable Securities - Held To

Marketable Securities - Held To Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Amortized cost
Held-to-maturity securities, amortized cost	$ 19,978	$ 31,689
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	448	863
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	20,426	32,552
Municipal securities
Amortized cost
Due after five years through ten years	0	274
Due after ten years	4,808	6,336
Gross unrealized holding gains
Due after five years through ten years	0	1
Due after ten years	65	239
Gross unrealized holding losses
Due after five years through ten years	0	0
Due after ten years	0	0
Fair value
Due after five years through ten years	0	275
Due after ten years	4,873	6,575
Residential mortgage-backed securities
Amortized cost
Held-to-maturity securities, amortized cost	15,170	25,079
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	383	623
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	15,553	25,702
Fixed rate | Pass-through
Amortized cost
Held-to-maturity securities, amortized cost	4,807	6,458
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	217	351
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	5,024	6,809
Fixed rate | Agency CMOs
Amortized cost
Held-to-maturity securities, amortized cost	6,674	14,033
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	94	219
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	6,768	14,252
Variable rate | Pass-through
Amortized cost
Held-to-maturity securities, amortized cost	2,848	3,618
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	58	41
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	2,906	3,659
Variable rate | Agency CMOs
Amortized cost
Held-to-maturity securities, amortized cost	841	970
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	14	12
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	$ 855	$ 982

Marketable Securities - Issuers

Marketable Securities - Issuers and the Carrying Values of Mortgage-Backed Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Marketable securities
Carrying value of marketable securities pledged	$ 200,900,000
Marketable securities classified as available-for-sale sold	1,951,000	$ 1,246,000	$ 7,910,000
Gross realized gains	268,000	121,000	4,400,000
Gross realized losses	0	67,000	0
Non-cash credit related other-than-temporary impairment	0	0	$ 0
Residential mortgage-backed securities
Marketable securities
Total residential mortgage-backed securities	462,704,000	503,796,000
Residential mortgage-backed securities | FNMA
Marketable securities
Total residential mortgage-backed securities	210,373,000	234,204,000
Residential mortgage-backed securities | GNMA
Marketable securities
Total residential mortgage-backed securities	42,221,000	48,283,000
Residential mortgage-backed securities | FHLMC
Marketable securities
Total residential mortgage-backed securities	202,822,000	209,788,000
Residential mortgage-backed securities | SBA
Marketable securities
Total residential mortgage-backed securities	6,608,000	8,166,000
Residential mortgage-backed securities | Other (including non-agency)
Marketable securities
Total residential mortgage-backed securities	$ 680,000	$ 3,355,000

Marketable Securities - Fair Va

Marketable Securities - Fair Value and Gross Unrealized Losses on Investment Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)investment	Dec. 31, 2015USD ($)
Marketable securities
Less than 12 months - Fair value	$ 457,286	$ 273,909
Less than 12 months - Unrealized loss	(6,322)	(1,331)
12 months or more - Fair value	99,645	244,871
12 months or more - Unrealized loss	(2,892)	(4,953)
Total - Fair value	556,931	518,780
Total - Unrealized loss	$ (9,214)	(6,284)
Number of investments that are temporarily impaired | investment	154
Aggregate carrying amount of cost-method investment	$ 846,200
U.S. Government and agencies
Marketable securities
Less than 12 months - Fair value	238,003	143,751
Less than 12 months - Unrealized loss	(2,448)	(723)
12 months or more - Fair value	9,205	92,961
12 months or more - Unrealized loss	(92)	(786)
Total - Fair value	247,208	236,712
Total - Unrealized loss	(2,540)	(1,509)
Corporate debt issues
Marketable securities
Less than 12 months - Fair value	0	0
Less than 12 months - Unrealized loss	0	0
12 months or more - Fair value	2,107	2,021
12 months or more - Unrealized loss	(322)	(405)
Total - Fair value	2,107	2,021
Total - Unrealized loss	(322)	(405)
Equity securities
Marketable securities
Less than 12 months - Fair value	0	544
Less than 12 months - Unrealized loss	0	(6)
12 months or more - Fair value	544	0
12 months or more - Unrealized loss	(6)	0
Total - Fair value	544	544
Total - Unrealized loss	(6)	(6)
Municipal securities
Marketable securities
Less than 12 months - Fair value	5,621	7,505
Less than 12 months - Unrealized loss	(37)	(4)
12 months or more - Fair value	66	0
12 months or more - Unrealized loss	(1)
Total - Fair value	5,687	7,505
Total - Unrealized loss	(38)	(4)
Residential mortgage-backed securities - agency | Agency CMOs
Marketable securities
Less than 12 months - Fair value	213,662	122,109
Less than 12 months - Unrealized loss	(3,837)	(598)
12 months or more - Fair value	87,723	149,889
12 months or more - Unrealized loss	(2,471)	(3,762)
Total - Fair value	301,385	271,998
Total - Unrealized loss	$ (6,308)	$ (4,360)

Marketable Securities - Categor

Marketable Securities - Categories of Investment Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)
Marketable securities
Total - Amortized cost	$ 11,034
Total - Fair value	13,995
Total - Unrealized gain	2,961
Accumulated impairment charges	(8,061)
Freddie Mac preferred shares
Marketable securities
Total - Amortized cost	1
Total - Fair value	27
Total - Unrealized gain	26
Accumulated impairment charges	(119)
Trust preferred investments
Marketable securities
Total - Amortized cost	11,033
Total - Fair value	13,968
Total - Unrealized gain	2,935
Accumulated impairment charges	$ (7,942)

Marketable Securities - Cumulat

Marketable Securities - Cumulative Roll Forward of Credit Related Impairment Losses Recognized in Earnings for Debt Securities Held and Not Intended to be Sold (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Cumulative roll forward of credit related impairment losses recognized in earnings for debt securities held and not intended to be sold:
Beginning balance	$ 8,436	$ 8,894
Credit losses on debt securities for which other-than-temporary impairment was not previously recognized	0	0
Reduction for losses realized during the year	(494)	(98)
Reduction for securities called realized during the year	0	(360)
Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized	0	0
Ending balance	$ 7,942	$ 8,436

Loans Receivable and Allowanc66

Loans Receivable and Allowance for Loan Losses - Summary of Originated and Acquired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	$ 7,746,648	$ 7,400,989
Deferred loan costs	22,375	20,065
Allowance for loan losses	(60,939)	(62,672)	$ (67,518)	$ (71,348)
Loans Receivable, Net	7,496,408	7,159,449
Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(11,638)	(10,778)
Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(171,580)	(172,840)
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(28,458)	(15,315)
Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	4,675,760	4,439,000
Allowance for loan losses		(16,121)	(16,249)	(20,607)
Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,715,729	2,741,277
Allowance for loan losses		(4,692)	(5,581)	(7,875)
Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	1,328,772	1,187,106
Allowance for loan losses		(3,941)	(4,550)	(7,245)
Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	631,259	510,617
Allowance for loan losses		(7,488)	(6,118)	(5,487)
Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	3,070,888	2,961,989
Allowance for loan losses		(44,849)	(46,904)	(46,079)
Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,513,669	2,524,274
Allowance for loan losses		(32,348)	(33,389)	(35,199)
Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	557,219	437,715
Allowance for loan losses		(12,501)	(13,515)	$ (10,880)
Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	6,698,391	6,531,938
Deferred loan costs	20,081	14,806
Allowance for loan losses	(55,293)	(60,970)	(67,518)
Loans Receivable, Net	6,456,778	6,304,311
Originated | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(11,638)	(10,778)
Originated | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(168,595)	(159,553)
Originated | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(26,168)	(11,132)
Originated | Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	4,076,170	4,064,688
Allowance for loan losses	(16,116)	(16,121)
Originated | Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,582,218	2,695,561
Allowance for loan losses	(4,656)	(4,692)
Originated | Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	1,026,315	1,055,907
Allowance for loan losses	(3,486)	(3,941)
Originated | Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	467,637	313,220
Allowance for loan losses	(7,974)	(7,488)
Originated | Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,622,221	2,467,250
Allowance for loan losses	(39,177)	(44,849)
Originated | Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,140,678	2,094,710
Allowance for loan losses	(23,667)	(32,348)
Originated | Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	481,543	372,540
Allowance for loan losses	(15,510)	(12,501)
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	1,048,257	869,051
Deferred loan costs	2,294	5,259
Allowance for loan losses	(5,646)	(1,702)	0
Loans Receivable, Net	1,039,630	855,138
Acquired | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	0	0
Acquired | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(2,985)	(13,287)
Acquired | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(2,290)	(4,183)
Acquired | Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	599,590	374,312
Allowance for loan losses	(1,771)	(229)	0
Acquired | Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	133,511	45,716
Allowance for loan losses	(71)	(18)	0
Acquired | Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	302,457	131,199
Allowance for loan losses	(1,047)	(101)	0
Acquired | Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	163,622	197,397
Allowance for loan losses	(653)	(110)	0
Acquired | Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	448,667	494,739
Allowance for loan losses	(3,875)	(1,473)	0
Acquired | Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	372,991	429,564
Allowance for loan losses	(3,008)	(1,439)	0
Acquired | Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	75,676	65,175
Allowance for loan losses	$ (867)	$ (34)	$ 0

Loans Receivable and Allowanc67

Loans Receivable and Allowance for Loan Losses - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Receivables [Abstract]
Serviced loans for others	$ 918.9	$ 776	$ 734.9
Percentage of loan portfolio secured by properties located in Pennsylvania	62.00%	65.00%
Adjustable rate loans	$ 2,755	$ 2,417
Fixed rate loans	$ 4,992	$ 4,984

Loans Receivable and Allowanc68

Loans Receivable and Allowance for Loan Losses - Outstanding Principal Balance and Related Carrying Value of Acquired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding principal balance	$ 1,056,486	$ 869,263
Carrying value	1,045,276	856,840
Acquired loans evaluated individually for future credit losses
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding principal balance	16,108	21,069
Carrying value	12,665	16,867
Acquired loans evaluated collectively for future credit losses
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding principal balance	1,040,378	848,194
Carrying value	$ 1,032,611	$ 839,973

Loans Receivable and Allowanc69

Loans Receivable and Allowance for Loan Losses - Changes in the Accretable Discount (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Beginning balance	$ 2,019	$ 0
Accretion	(1,170)	(377)
Net reclassification from nonaccretable yield	1,338	724
Ending balance	$ 2,187	2,019
LNB | Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
LNB Bancorp, Inc. acquisition		$ 1,672

Loans Receivable and Allowanc70

Loans Receivable and Allowance for Loan Losses - Composition of Acquired Impaired Loans by Portfolio Segment and by Class of Financing Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	$ 108,061	$ 117,851	$ 137,179
Average recorded investment in impaired loans	118,675	130,528	159,638
Interest income/ accretion recognized	5,596	5,462	5,871
Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	12,665	16,867
Outstanding principal balance	16,108	21,069
Related impairment reserve	267	375
Average recorded investment in impaired loans	14,766	17,812
Interest income/ accretion recognized	1,170	377
Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	38,606	37,679	41,134
Average recorded investment in impaired loans	37,420	37,175	42,363
Interest income/ accretion recognized	1,741	1,542	1,368
Personal Banking | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	2,818	4,332
Outstanding principal balance	5,034	6,857
Related impairment reserve	215	22
Average recorded investment in impaired loans	3,575	4,610
Interest income/ accretion recognized	438	110
Personal Banking | Residential mortgage loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	24,193	24,858	27,039
Average recorded investment in impaired loans	24,483	24,554	28,227
Interest income/ accretion recognized	1,079	944	817
Personal Banking | Residential mortgage loans | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	1,319	1,981
Outstanding principal balance	2,062	2,910
Related impairment reserve	204	14
Average recorded investment in impaired loans	1,650	2,083
Interest income/ accretion recognized	202	41
Personal Banking | Home equity loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	9,304	9,369	11,275
Average recorded investment in impaired loans	9,234	9,644	11,753
Interest income/ accretion recognized	496	497	485
Personal Banking | Home equity loans | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	1,363	2,084
Outstanding principal balance	2,669	3,455
Related impairment reserve	8	6
Average recorded investment in impaired loans	1,724	2,222
Interest income/ accretion recognized	185	51
Personal Banking | Consumer loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	5,109	3,452	2,820
Average recorded investment in impaired loans	3,703	2,977	2,383
Interest income/ accretion recognized	166	101	66
Personal Banking | Consumer loans | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	136	267
Outstanding principal balance	303	492
Related impairment reserve	3	2
Average recorded investment in impaired loans	201	305
Interest income/ accretion recognized	51	18
Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	69,455	80,172	96,045
Average recorded investment in impaired loans	81,255	93,353	117,275
Interest income/ accretion recognized	3,855	3,920	4,503
Commercial Banking | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	9,847	12,535
Outstanding principal balance	11,074	14,212
Related impairment reserve	52	353
Average recorded investment in impaired loans	11,191	13,202
Interest income/ accretion recognized	732	267
Commercial Banking | Commercial real estate loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	53,928	66,009	74,337
Average recorded investment in impaired loans	64,350	77,166	90,187
Interest income/ accretion recognized	2,864	3,226	3,589
Commercial Banking | Commercial real estate loans | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	9,596	12,288
Outstanding principal balance	10,809	13,946
Related impairment reserve	52	353
Average recorded investment in impaired loans	10,942	12,867
Interest income/ accretion recognized	721	249
Commercial Banking | Commercial loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	15,527	14,163	21,708
Average recorded investment in impaired loans	16,905	16,187	27,088
Interest income/ accretion recognized	991	694	$ 914
Commercial Banking | Commercial loans | Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	251	247
Outstanding principal balance	265	266
Related impairment reserve	0	0
Average recorded investment in impaired loans	249	335
Interest income/ accretion recognized	$ 11	$ 18

Loans Receivable and Allowanc71

Loans Receivable and Allowance for Loan Losses - Changes in the Allowance for Losses on Loans Receivable (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				$ 62,672				$ 67,518				$ 71,348	$ 62,672	$ 67,518	$ 71,348
Provision	$ 2,145	$ 5,538	$ 4,199	1,660	$ 4,595	$ 3,167	$ 1,050	900	$ 1,078	$ 3,466	$ 8,285	7,485	13,542	9,712	20,314
Charge-offs													(24,881)	(26,333)	(30,745)
Recoveries													9,606	11,775	6,601
Balance at the end of the period	60,939				62,672				67,518				60,939	62,672	67,518
Personal Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				16,121				16,249				20,607	16,121	16,249	20,607
Provision														8,582	4,202
Charge-offs														(10,846)	(10,387)
Recoveries														2,136	1,827
Balance at the end of the period					16,121				16,249					16,121	16,249
Personal Banking | Residential mortgage loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				4,692				5,581				7,875	4,692	5,581	7,875
Provision														(96)	(556)
Charge-offs														(1,057)	(2,181)
Recoveries														264	443
Balance at the end of the period					4,692				5,581					4,692	5,581
Personal Banking | Home equity loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,941				4,550				7,245	3,941	4,550	7,245
Provision														693	(1,106)
Charge-offs														(1,716)	(1,783)
Recoveries														414	194
Balance at the end of the period					3,941				4,550					3,941	4,550
Personal Banking | Consumer loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				7,488				6,118				5,487	7,488	6,118	5,487
Provision														7,985	5,864
Charge-offs														(8,073)	(6,423)
Recoveries														1,458	1,190
Balance at the end of the period					7,488				6,118					7,488	6,118
Commercial Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				44,849				46,904				46,079	44,849	46,904	46,079
Provision														3,308	16,409
Charge-offs														(13,555)	(20,358)
Recoveries														8,192	4,774
Balance at the end of the period					44,849				46,904					44,849	46,904
Commercial Banking | Commercial real estate loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				32,348				33,389				35,199	32,348	33,389	35,199
Provision														540	4,417
Charge-offs														(5,741)	(8,422)
Recoveries														4,160	2,195
Balance at the end of the period					32,348				33,389					32,348	33,389
Commercial Banking | Commercial loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				12,501				13,515				10,880	12,501	13,515	10,880
Provision														2,768	11,992
Charge-offs														(7,814)	(11,936)
Recoveries														4,032	2,579
Balance at the end of the period					12,501				13,515					12,501	13,515
Unallocated
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				0				4,365				$ 4,662	0	4,365	4,662
Provision														(4,365)	(297)
Charge-offs														0	0
Recoveries														0	0
Balance at the end of the period					0				4,365					0	4,365
Originated
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				60,970				67,518					60,970	67,518
Provision													7,266	7,525
Charge-offs													(21,111)	(24,401)
Recoveries													8,168	10,328
Balance at the end of the period	55,293				60,970				67,518				55,293	60,970	67,518
Originated | Personal Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				16,121									16,121
Provision													12,251
Charge-offs													(14,543)
Recoveries													2,287
Balance at the end of the period	16,116				16,121								16,116	16,121
Originated | Personal Banking | Residential mortgage loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				4,692									4,692
Provision													2,906
Charge-offs													(3,228)
Recoveries													286
Balance at the end of the period	4,656				4,692								4,656	4,692
Originated | Personal Banking | Home equity loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,941									3,941
Provision													293
Charge-offs													(1,090)
Recoveries													342
Balance at the end of the period	3,486				3,941								3,486	3,941
Originated | Personal Banking | Consumer loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				7,488									7,488
Provision													9,052
Charge-offs													(10,225)
Recoveries													1,659
Balance at the end of the period	7,974				7,488								7,974	7,488
Originated | Commercial Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				44,849									44,849
Provision													(4,985)
Charge-offs													(6,568)
Recoveries													5,881
Balance at the end of the period	39,177				44,849								39,177	44,849
Originated | Commercial Banking | Commercial real estate loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				32,348									32,348
Provision													(9,819)
Charge-offs													(2,403)
Recoveries													3,541
Balance at the end of the period	23,667				32,348								23,667	32,348
Originated | Commercial Banking | Commercial loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				12,501									12,501
Provision													4,834
Charge-offs													(4,165)
Recoveries													2,340
Balance at the end of the period	15,510				12,501								15,510	12,501
Acquired
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				1,702				0					1,702	0
Provision													6,276	2,187
Charge-offs													(3,770)	(1,932)
Recoveries													1,438	1,447
Balance at the end of the period	5,646				1,702				0				5,646	1,702	0
Acquired | Personal Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				229				0					229	0
Provision													3,283	482
Charge-offs													(2,381)	(978)
Recoveries													640	725
Balance at the end of the period	1,771				229				0				1,771	229	0
Acquired | Personal Banking | Residential mortgage loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				18				0					18	0
Provision													146	47
Charge-offs													(252)	(69)
Recoveries													159	40
Balance at the end of the period	71				18				0				71	18	0
Acquired | Personal Banking | Home equity loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				101				0					101	0
Provision													2,065	247
Charge-offs													(1,449)	(708)
Recoveries													330	562
Balance at the end of the period	1,047				101				0				1,047	101	0
Acquired | Personal Banking | Consumer loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				110				0					110	0
Provision													1,072	188
Charge-offs													(680)	(201)
Recoveries													151	123
Balance at the end of the period	653				110				0				653	110	0
Acquired | Commercial Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				1,473				0					1,473	0
Provision													2,993	1,705
Charge-offs													(1,389)	(954)
Recoveries													798	722
Balance at the end of the period	3,875				1,473				0				3,875	1,473	0
Acquired | Commercial Banking | Commercial real estate loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				1,439				0					1,439	0
Provision													2,116	1,545
Charge-offs													(1,337)	(585)
Recoveries													790	479
Balance at the end of the period	3,008				1,439				0				3,008	1,439	0
Acquired | Commercial Banking | Commercial loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				$ 34				$ 0					34	0
Provision													877	160
Charge-offs													(52)	(369)
Recoveries													8	243
Balance at the end of the period	$ 867				$ 34				$ 0				$ 867	$ 34	$ 0

Loans Receivable and Allowanc72

Loans Receivable and Allowance for Loan Losses - Loan Portfolio by Portfolio Segment and by Class of Financing Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	$ 7,557,347	$ 7,222,121
Allowance for loan losses	60,939	62,672
Recorded investment in loans on nonaccrual	79,536	71,662
Recorded investment in loans 90 days or more past maturity and still accruing	649	1,334
TDRs	42,926	51,115	$ 61,788
Allowance for TDRs	4,590	4,682
Additional commitments to customers with loans classified as TDRs	438	320
Nonaccrual TDRs	16,346	21,118
Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	4,686,497	4,448,287
Allowance for loan losses	17,887	16,350
Recorded investment in loans on nonaccrual	31,238	30,746
Recorded investment in loans 90 days or more past maturity and still accruing	85	980
TDRs	9,112	8,658
Allowance for TDRs	1,158	1,794
Additional commitments to customers with loans classified as TDRs	4	0
Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	2,714,764	2,740,892
Allowance for loan losses	4,727	4,710
Recorded investment in loans on nonaccrual	18,264	19,772
Recorded investment in loans 90 days or more past maturity and still accruing	0	4
TDRs	7,299	6,360
Allowance for TDRs	708	1,189
Additional commitments to customers with loans classified as TDRs	0	0
Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	1,328,772	1,187,106
Allowance for loan losses	4,533	4,042
Recorded investment in loans on nonaccrual	7,865	7,522
Recorded investment in loans 90 days or more past maturity and still accruing	0	0
TDRs	1,813	2,298
Allowance for TDRs	450	605
Additional commitments to customers with loans classified as TDRs	4	0
Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	642,961	520,289
Allowance for loan losses	8,627	7,598
Recorded investment in loans on nonaccrual	5,109	3,452
Recorded investment in loans 90 days or more past maturity and still accruing	85	976
TDRs	0	0
Allowance for TDRs	0	0
Additional commitments to customers with loans classified as TDRs	0	0
Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	2,870,850	2,773,834
Allowance for loan losses	43,052	46,322
Recorded investment in loans on nonaccrual	48,298	40,916
Recorded investment in loans 90 days or more past maturity and still accruing	564	354
TDRs	33,814	42,457
Allowance for TDRs	3,432	2,888
Additional commitments to customers with loans classified as TDRs	434	320
Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	2,342,089	2,351,434
Allowance for loan losses	26,675	33,787
Recorded investment in loans on nonaccrual	38,724	33,421
Recorded investment in loans 90 days or more past maturity and still accruing	564	206
TDRs	24,483	31,970
Allowance for TDRs	2,072	2,257
Additional commitments to customers with loans classified as TDRs	417	241
Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	528,761	422,400
Allowance for loan losses	16,377	12,535
Recorded investment in loans on nonaccrual	9,574	7,495
Recorded investment in loans 90 days or more past maturity and still accruing	0	148
TDRs	9,331	10,487
Allowance for TDRs	1,360	631
Additional commitments to customers with loans classified as TDRs	$ 17	$ 79

Loans Receivable and Allowanc73

Loans Receivable and Allowance for Loan Losses - Composition of Impaired Loans by Portfolio Segment and Class of Financing Receivable (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	$ 79,536	$ 71,662
Total impaired loans	108,061	117,851	$ 137,179
Average recorded investment in impaired loans	118,675	130,528	159,638
Interest income/ accretion recognized	5,596	5,462	5,871
Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	31,238	30,746
Total impaired loans	38,606	37,679	41,134
Average recorded investment in impaired loans	37,420	37,175	42,363
Interest income/ accretion recognized	1,741	1,542	1,368
Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	48,298	40,916
Total impaired loans	69,455	80,172	96,045
Average recorded investment in impaired loans	81,255	93,353	117,275
Interest income/ accretion recognized	3,855	3,920	4,503
Residential mortgage loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	18,264	19,772
Total impaired loans	24,193	24,858	27,039
Average recorded investment in impaired loans	24,483	24,554	28,227
Interest income/ accretion recognized	1,079	944	817
Home equity loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	7,865	7,522
Total impaired loans	9,304	9,369	11,275
Average recorded investment in impaired loans	9,234	9,644	11,753
Interest income/ accretion recognized	496	497	485
Consumer loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	5,109	3,452
Total impaired loans	5,109	3,452	2,820
Average recorded investment in impaired loans	3,703	2,977	2,383
Interest income/ accretion recognized	166	101	66
Commercial real estate loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	38,724	33,421
Total impaired loans	53,928	66,009	74,337
Average recorded investment in impaired loans	64,350	77,166	90,187
Interest income/ accretion recognized	2,864	3,226	3,589
Commercial loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	9,574	7,495
Total impaired loans	15,527	14,163	21,708
Average recorded investment in impaired loans	16,905	16,187	27,088
Interest income/ accretion recognized	991	694	914
90 days or greater delinquent
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	45,181	43,268	41,326
90 days or greater delinquent | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	22,544	24,360	26,752
90 days or greater delinquent | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	22,637	18,908	14,574
90 days or greater delinquent | Residential mortgage loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	13,169	15,810	17,696
90 days or greater delinquent | Home equity loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	5,552	5,650	6,606
90 days or greater delinquent | Consumer loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	3,823	2,900	2,450
90 days or greater delinquent | Commercial real estate loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	19,264	16,449	11,099
90 days or greater delinquent | Commercial loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	3,373	2,459	3,475
Less than 90 days delinquent
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	34,355	28,394	38,482
Loans less than 90 days delinquent reviewed for impairment	6,459	18,135	31,666
TDRs less than 90 days delinquent not included elsewhere	22,066	28,054	25,705
Less than 90 days delinquent | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	8,694	6,386	6,831
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	7,368	6,933	7,551
Less than 90 days delinquent | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	25,661	22,008	31,651
Loans less than 90 days delinquent reviewed for impairment	6,459	18,135	31,666
TDRs less than 90 days delinquent not included elsewhere	14,698	21,121	18,154
Less than 90 days delinquent | Residential mortgage loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	5,095	3,962	3,498
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	5,929	5,086	5,845
Less than 90 days delinquent | Home equity loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	2,313	1,872	2,963
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	1,439	1,847	1,706
Less than 90 days delinquent | Consumer loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	1,286	552	370
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	0	0	0
Less than 90 days delinquent | Commercial real estate loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	19,460	16,972	27,548
Loans less than 90 days delinquent reviewed for impairment	3,622	16,121	26,400
TDRs less than 90 days delinquent not included elsewhere	11,582	16,467	12,128
Less than 90 days delinquent | Commercial loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	6,201	5,036	4,103
Loans less than 90 days delinquent reviewed for impairment	2,837	2,014	5,266
TDRs less than 90 days delinquent not included elsewhere	$ 3,116	$ 4,654	$ 6,026

Loans Receivable and Allowanc74

Loans Receivable and Allowance for Loan Losses - Evaluation of Impaired Loans by Portfolio Segment and by Class of Financing Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	$ 7,503,912	$ 7,147,649
Loans individually evaluated for impairment	53,435	74,472
Loans individually evaluated for impairment for which there is a related impairment reserve	48,056	53,189
Related impairment reserve	6,123	5,008
Loans individually evaluated for impairment for which there is no related reserve	5,379	21,283
Personal Banking
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	4,676,277	4,438,708
Loans individually evaluated for impairment	10,220	9,579
Loans individually evaluated for impairment for which there is a related impairment reserve	10,220	9,579
Related impairment reserve	1,188	1,844
Loans individually evaluated for impairment for which there is no related reserve	0	0
Personal Banking | Residential mortgage loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	2,706,484	2,733,741
Loans individually evaluated for impairment	8,280	7,151
Loans individually evaluated for impairment for which there is a related impairment reserve	8,280	7,151
Related impairment reserve	709	1,189
Loans individually evaluated for impairment for which there is no related reserve	0	0
Personal Banking | Home equity loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	1,326,958	1,184,808
Loans individually evaluated for impairment	1,814	2,298
Loans individually evaluated for impairment for which there is a related impairment reserve	1,814	2,298
Related impairment reserve	450	605
Loans individually evaluated for impairment for which there is no related reserve	0	0
Personal Banking | Consumer loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	642,835	520,159
Loans individually evaluated for impairment	126	130
Loans individually evaluated for impairment for which there is a related impairment reserve	126	130
Related impairment reserve	29	50
Loans individually evaluated for impairment for which there is no related reserve	0	0
Commercial Banking
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	2,827,635	2,708,941
Loans individually evaluated for impairment	43,215	64,893
Loans individually evaluated for impairment for which there is a related impairment reserve	37,836	43,610
Related impairment reserve	4,935	3,164
Loans individually evaluated for impairment for which there is no related reserve	5,379	21,283
Commercial Banking | Commercial real estate loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	2,309,186	2,297,599
Loans individually evaluated for impairment	32,903	53,835
Loans individually evaluated for impairment for which there is a related impairment reserve	27,594	35,937
Related impairment reserve	3,545	2,675
Loans individually evaluated for impairment for which there is no related reserve	5,309	17,898
Commercial Banking | Commercial loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	518,449	411,342
Loans individually evaluated for impairment	10,312	11,058
Loans individually evaluated for impairment for which there is a related impairment reserve	10,242	7,673
Related impairment reserve	1,390	489
Loans individually evaluated for impairment for which there is no related reserve	$ 70	$ 3,385

Loans Receivable and Allowanc75

Loans Receivable and Allowance for Loan Losses - Roll Forward of Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)contract	Dec. 31, 2015USD ($)contract
Number of contract
Beginning balance | contract	227	248
Number of contracts new TDRs | contract	34	26
Number of re-modified TDRs | contract	7	3
Ending balance | contract	225	227
Roll forward of troubled debt restructurings
Beginning TDR balance:	$ 51,115	$ 61,788
New TDRs	6,365	8,537
Re-modified TDRs	3,414	6,386
Net paydowns	(9,037)	(13,270)
Ending TDR balance:	42,926	51,115
Accruing TDRs	26,580	29,997
Non-accrual TDRs	$ 16,346	$ 21,118
Residential mortgage loans
Number of contract
Number of contracts charged off | contract	0	0
Number of contracts paid off | contract	4	2
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ 0	$ 0
Amount of contracts paid off	$ (151)	$ (109)
Home equity loans
Number of contract
Number of contracts charged off | contract	0	4
Number of contracts paid off | contract		5
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ 0	$ (159)
Amount of contracts paid off	$ (534)	$ (194)
Commercial real estate loans
Number of contract
Number of contracts charged off | contract	1	4
Number of contracts paid off | contract	19	15
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ (120)	$ (179)
Amount of contracts paid off	$ (6,170)	$ (9,208)
Commercial loans
Number of contract
Number of contracts charged off | contract	2	2
Number of contracts paid off | contract	10	14
Number of contracts transferred to real estate owned | contract	0	1
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ (142)	$ (387)
Amount of contracts paid off	(1,814)	(1,728)
Transferred to real estate owned	$ 0	$ (362)

Loans Receivable and Allowanc76

Loans Receivable and Allowance for Loan Losses - Troubled Debt Restructuring (Including Re-Modified TDRs) by Portfolio Segment and by Class of Financing Receivable (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)contract	Dec. 31, 2015USD ($)contract	Dec. 31, 2014USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	41	29	57
Recorded investment at the time of modification	$ 9,779	$ 14,923	$ 13,132
Current recorded investment	7,509	14,881	11,808
Current allowance	$ 1,217	$ 1,245	$ 1,904
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	4		4
Recorded investment at the time of modification	$ 962		$ 500
Current recorded investment	958		477
Current allowance	$ 564		$ 8
Personal Banking
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	14	9	23
Recorded investment at the time of modification	$ 1,674	$ 465	$ 3,372
Current recorded investment	1,648	454	3,197
Current allowance	$ 224	$ 42	$ 211
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	0		2
Recorded investment at the time of modification	$ 0		$ 438
Current recorded investment	0		408
Current allowance	$ 0		$ 1
Personal Banking | Residential mortgage loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	7	6	17
Recorded investment at the time of modification	$ 1,199	$ 364	$ 2,802
Current recorded investment	1,177	357	2,690
Current allowance	$ 114	$ 21	$ 210
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	0		1
Recorded investment at the time of modification	$ 0		$ 78
Current recorded investment	0		77
Current allowance	$ 0		$ 0
Personal Banking | Home equity loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	7	3	6
Recorded investment at the time of modification	$ 475	$ 101	$ 570
Current recorded investment	471	97	507
Current allowance	$ 110	$ 21	$ 1
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	0		1
Recorded investment at the time of modification	$ 0		$ 360
Current recorded investment	0		331
Current allowance	$ 0		$ 1
Personal Banking | Consumer loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	0	0	0
Recorded investment at the time of modification	$ 0	$ 0	$ 0
Current recorded investment	0	0	0
Current allowance	$ 0	$ 0	$ 0
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	0		0
Recorded investment at the time of modification	$ 0		$ 0
Current recorded investment	0		0
Current allowance	$ 0		$ 0
Personal Banking | Commercial real estate loans
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		1
Commercial Banking
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	27	20	34
Recorded investment at the time of modification	$ 8,105	$ 14,458	$ 9,760
Current recorded investment	5,861	14,427	8,611
Current allowance	$ 993	$ 1,203	$ 1,693
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	4		2
Recorded investment at the time of modification	$ 962		$ 62
Current recorded investment	958		69
Current allowance	$ 564		$ 7
Commercial Banking | Commercial real estate loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	7	11	11
Recorded investment at the time of modification	$ 3,729	$ 12,258	$ 2,010
Current recorded investment	3,643	12,243	1,793
Current allowance	485	$ 1,047	$ 202
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract			1
Recorded investment at the time of modification	429		$ 12
Current recorded investment	425		5
Current allowance	$ 31		$ 1
Commercial Banking | Commercial loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	20	9	23
Recorded investment at the time of modification	$ 4,376	$ 2,200	$ 7,750
Current recorded investment	2,218	2,184	6,818
Current allowance	$ 508	$ 156	$ 1,491
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract	3		1
Recorded investment at the time of modification	$ 533		$ 50
Current recorded investment	533		64
Current allowance	$ 533		$ 6

Loans Receivable and Allowanc77

Loans Receivable and Allowance for Loan Losses - Troubled Debt Restructurings by Type of Modification (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2016USD ($)contract	Dec. 31, 2015USD ($)contract	Dec. 31, 2014USD ($)contract
Troubled debt restructurings
Number of contracts | contract	41	29	57
Total	$ 7,509	$ 14,881	$ 11,808
Number of re-modified TDRs | contract	7	3
Total	$ 2,196	$ 6,384
Rate
Troubled debt restructurings
Total	478	341
Total	0	83
Payment
Troubled debt restructurings
Total	753	0
Total	502	0
Maturity date
Troubled debt restructurings
Total	3,932	13,336
Total	1,329	6,256
Other
Troubled debt restructurings
Total	2,346	1,204
Total	$ 365	$ 45
Personal Banking
Troubled debt restructurings
Number of contracts | contract	14	9	23
Total	$ 1,648	$ 454	$ 3,197
Number of re-modified TDRs | contract	1	2
Total	$ 192	$ 128
Personal Banking | Rate
Troubled debt restructurings
Total	478	167
Total	0	83
Personal Banking | Payment
Troubled debt restructurings
Total	0	0
Total	0	0
Personal Banking | Maturity date
Troubled debt restructurings
Total	774	111
Total	0	0
Personal Banking | Other
Troubled debt restructurings
Total	396	176
Total	$ 192	$ 45
Personal Banking | Residential mortgage loans
Troubled debt restructurings
Number of contracts | contract	7	6	17
Total	$ 1,177	$ 357	$ 2,690
Number of re-modified TDRs | contract	0	1
Total	$ 0	$ 45
Personal Banking | Residential mortgage loans | Rate
Troubled debt restructurings
Total	358	71
Total	0	0
Personal Banking | Residential mortgage loans | Payment
Troubled debt restructurings
Total	0	0
Total	0	0
Personal Banking | Residential mortgage loans | Maturity date
Troubled debt restructurings
Total	771	110
Total	0	0
Personal Banking | Residential mortgage loans | Other
Troubled debt restructurings
Total	48	176
Total	$ 0	$ 45
Personal Banking | Home equity loans
Troubled debt restructurings
Number of contracts | contract	7	3	6
Total	$ 471	$ 97	$ 507
Number of re-modified TDRs | contract	1	1
Total	$ 192	$ 83
Personal Banking | Home equity loans | Rate
Troubled debt restructurings
Total	120	96
Total	0	83
Personal Banking | Home equity loans | Payment
Troubled debt restructurings
Total	0	0
Total	0	0
Personal Banking | Home equity loans | Maturity date
Troubled debt restructurings
Total	3	1
Total	0	0
Personal Banking | Home equity loans | Other
Troubled debt restructurings
Total	348	0
Total	$ 192	$ 0
Personal Banking | Consumer loans
Troubled debt restructurings
Number of contracts | contract	0	0	0
Total	$ 0	$ 0	$ 0
Number of re-modified TDRs | contract	0	0
Total	$ 0	$ 0
Personal Banking | Consumer loans | Rate
Troubled debt restructurings
Total	0	0
Total	0	0
Personal Banking | Consumer loans | Payment
Troubled debt restructurings
Total	0	0
Total	0	0
Personal Banking | Consumer loans | Maturity date
Troubled debt restructurings
Total	0	0
Total	0	0
Personal Banking | Consumer loans | Other
Troubled debt restructurings
Total	0	0
Total	$ 0	$ 0
Commercial Banking
Troubled debt restructurings
Number of contracts | contract	27	20	34
Total	$ 5,861	$ 14,427	$ 8,611
Number of re-modified TDRs | contract	6	1
Total	$ 2,004	$ 6,256
Commercial Banking | Rate
Troubled debt restructurings
Total	0	174
Total	0	0
Commercial Banking | Payment
Troubled debt restructurings
Total	753	0
Total	502	0
Commercial Banking | Maturity date
Troubled debt restructurings
Total	3,158	13,225
Total	1,329	6,256
Commercial Banking | Other
Troubled debt restructurings
Total	1,950	1,028
Total	$ 173	$ 0
Commercial Banking | Commercial real estate loans
Troubled debt restructurings
Number of contracts | contract	7	11	11
Total	$ 3,643	$ 12,243	$ 1,793
Number of re-modified TDRs | contract	2	1
Total	$ 1,502	$ 6,256
Commercial Banking | Commercial real estate loans | Rate
Troubled debt restructurings
Total	0	174
Total	0	0
Commercial Banking | Commercial real estate loans | Payment
Troubled debt restructurings
Total	425	0
Total	0	0
Commercial Banking | Commercial real estate loans | Maturity date
Troubled debt restructurings
Total	1,980	11,961
Total	1,329	6,256
Commercial Banking | Commercial real estate loans | Other
Troubled debt restructurings
Total	1,238	108
Total	$ 173	$ 0
Commercial Banking | Commercial loans
Troubled debt restructurings
Number of contracts | contract	20	9	23
Total	$ 2,218	$ 2,184	$ 6,818
Number of re-modified TDRs | contract	4	0
Total	$ 502	$ 0
Commercial Banking | Commercial loans | Rate
Troubled debt restructurings
Total	0	0
Total	0	0
Commercial Banking | Commercial loans | Payment
Troubled debt restructurings
Total	328	0
Total	502	0
Commercial Banking | Commercial loans | Maturity date
Troubled debt restructurings
Total	1,178	1,264
Total	0	0
Commercial Banking | Commercial loans | Other
Troubled debt restructurings
Total	712	920
Total	$ 0	$ 0

Loans Receivable and Allowanc78

Loans Receivable and Allowance for Loan Losses - Loan Delinquencies (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Loan payment delinquencies
Total delinquency	$ 121,594	$ 135,228
Current	7,435,753	7,086,893
Total loans	7,557,347	7,222,121
90 days or greater delinquent and accruing	2,824	3,750
Personal Banking
Loan payment delinquencies
Total loans	4,686,497	4,448,287
Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total loans	2,714,764	2,740,892
Personal Banking | Home equity loans
Loan payment delinquencies
Total loans	1,328,772	1,187,106
Personal Banking | Consumer loans
Loan payment delinquencies
Total loans	642,961	520,289
Commercial Banking
Loan payment delinquencies
Total loans	2,870,850	2,773,834
Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total loans	2,342,089	2,351,434
Commercial Banking | Commercial loans
Loan payment delinquencies
Total loans	528,761	422,400
Originated
Loan payment delinquencies
Total delinquency	105,990	120,633
Current	6,406,081	6,244,648
Total loans	6,512,071	6,365,281
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking
Loan payment delinquencies
Total delinquency	72,003	71,854
Current	4,012,610	3,996,862
Total loans	4,084,613	4,068,716
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	44,810	48,608
Current	2,536,443	2,646,568
Total loans	2,581,253	2,695,176
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	11,873	11,957
Current	1,014,442	1,043,950
Total loans	1,026,315	1,055,907
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	15,320	11,289
Current	461,725	306,344
Total loans	477,045	317,633
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	33,987	48,779
Current	2,393,471	2,247,786
Total loans	2,427,458	2,296,565
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	27,856	44,029
Current	1,944,227	1,891,128
Total loans	1,972,083	1,935,157
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	6,131	4,750
Current	449,244	356,658
Total loans	455,375	361,408
90 days or greater delinquent and accruing	0	0
Acquired
Loan payment delinquencies
Total delinquency	15,604	14,595
Current	1,029,672	842,245
Total loans	1,045,276	856,840
90 days or greater delinquent and accruing	2,824	3,750
Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	6,670	5,173
Current	595,214	374,398
Total loans	601,884	379,571
90 days or greater delinquent and accruing	671	1,028
Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	2,424	1,475
Current	131,087	44,241
Total loans	133,511	45,716
90 days or greater delinquent and accruing	452	540
Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	2,251	2,439
Current	300,206	128,760
Total loans	302,457	131,199
90 days or greater delinquent and accruing	204	462
Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	1,995	1,259
Current	163,921	201,397
Total loans	165,916	202,656
90 days or greater delinquent and accruing	15	26
Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	8,934	9,422
Current	434,458	467,847
Total loans	443,392	477,269
90 days or greater delinquent and accruing	2,153	2,722
Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	8,286	8,107
Current	361,720	408,170
Total loans	370,006	416,277
90 days or greater delinquent and accruing	2,006	2,582
Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	648	1,315
Current	72,738	59,677
Total loans	73,386	60,992
90 days or greater delinquent and accruing	147	140
30-59 days delinquent
Loan payment delinquencies
Total delinquency	55,614	66,595
30-59 days delinquent | Originated
Loan payment delinquencies
Total delinquency	49,336	60,380
30-59 days delinquent | Originated | Personal Banking
Loan payment delinquencies
Total delinquency	40,595	36,465
30-59 days delinquent | Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	26,212	25,503
30-59 days delinquent | Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	5,785	4,870
30-59 days delinquent | Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	8,598	6,092
30-59 days delinquent | Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	8,741	23,915
30-59 days delinquent | Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	7,674	22,212
30-59 days delinquent | Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	1,067	1,703
30-59 days delinquent | Acquired
Loan payment delinquencies
Total delinquency	6,278	6,215
30-59 days delinquent | Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	3,464	2,385
30-59 days delinquent | Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	1,174	440
30-59 days delinquent | Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	1,020	936
30-59 days delinquent | Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	1,270	1,009
30-59 days delinquent | Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	2,814	3,830
30-59 days delinquent | Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	2,703	2,665
30-59 days delinquent | Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	111	1,165
60-89 days delinquent
Loan payment delinquencies
Total delinquency	17,975	21,615
60-89 days delinquent | Originated
Loan payment delinquencies
Total delinquency	15,946	19,190
60-89 days delinquent | Originated | Personal Banking
Loan payment delinquencies
Total delinquency	10,315	11,717
60-89 days delinquent | Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	5,806	7,541
60-89 days delinquent | Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	1,305	1,836
60-89 days delinquent | Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	3,204	2,340
60-89 days delinquent | Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	5,631	7,473
60-89 days delinquent | Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	3,674	6,875
60-89 days delinquent | Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	1,957	598
60-89 days delinquent | Acquired
Loan payment delinquencies
Total delinquency	2,029	2,425
60-89 days delinquent | Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	1,084	1,072
60-89 days delinquent | Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	421	249
60-89 days delinquent | Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	258	642
60-89 days delinquent | Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	405	181
60-89 days delinquent | Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	945	1,353
60-89 days delinquent | Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	821	1,353
60-89 days delinquent | Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	124	0
90 days or greater delinquent
Loan payment delinquencies
Total delinquency	48,005	47,018
90 days or greater delinquent | Originated
Loan payment delinquencies
Total delinquency	40,708	41,063
90 days or greater delinquent | Originated | Personal Banking
Loan payment delinquencies
Total delinquency	21,093	23,672
90 days or greater delinquent | Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	12,792	15,564
90 days or greater delinquent | Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	4,783	5,251
90 days or greater delinquent | Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	3,518	2,857
90 days or greater delinquent | Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	19,615	17,391
90 days or greater delinquent | Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	16,508	14,942
90 days or greater delinquent | Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	3,107	2,449
90 days or greater delinquent | Acquired
Loan payment delinquencies
Total delinquency	7,297	5,955
90 days or greater delinquent | Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	2,122	1,716
90 days or greater delinquent | Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	829	786
90 days or greater delinquent | Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	973	861
90 days or greater delinquent | Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	320	69
90 days or greater delinquent | Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	5,175	4,239
90 days or greater delinquent | Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	4,762	4,089
90 days or greater delinquent | Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	$ 413	$ 150

Loans Receivable and Allowanc79

Loans Receivable and Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Credit quality indicators
Total loans	$ 7,557,347	$ 7,222,121
Pass
Credit quality indicators
Total loans	7,278,068	6,952,327
Special mention
Credit quality indicators
Total loans	60,916	77,120
Substandard
Credit quality indicators
Total loans	218,363	190,109
Doubtful
Credit quality indicators
Total loans	0	1,225
Loss
Credit quality indicators
Total loans	0	1,340
Special mention or substandard | Minimum
Credit quality indicators
Total loans	1,000
Personal Banking
Credit quality indicators
Total loans	4,686,497	4,448,287
Personal Banking | Residential mortgage loans
Credit quality indicators
Total loans	2,714,764	2,740,892
Personal Banking | Home equity loans
Credit quality indicators
Total loans	1,328,772	1,187,106
Personal Banking | Consumer loans
Credit quality indicators
Total loans	642,961	520,289
Commercial Banking
Credit quality indicators
Total loans	2,870,850	2,773,834
Commercial Banking | Commercial real estate loans
Credit quality indicators
Total loans	2,342,089	2,351,434
Commercial Banking | Commercial loans
Credit quality indicators
Total loans	528,761	422,400
Originated
Credit quality indicators
Total loans	6,512,071	6,365,281
Originated | Pass
Credit quality indicators
Total loans	6,281,250	6,121,713
Originated | Special mention
Credit quality indicators
Total loans	51,524	69,541
Originated | Substandard
Credit quality indicators
Total loans	179,297	171,462
Originated | Doubtful
Credit quality indicators
Total loans	0	1,225
Originated | Loss
Credit quality indicators
Total loans	0	1,340
Originated | Personal Banking
Credit quality indicators
Total loans	4,084,613	4,068,716
Originated | Personal Banking | Pass
Credit quality indicators
Total loans	4,057,836	4,044,118
Originated | Personal Banking | Special mention
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Substandard
Credit quality indicators
Total loans	26,777	23,258
Originated | Personal Banking | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Loss
Credit quality indicators
Total loans	0	1,340
Originated | Personal Banking | Residential mortgage loans
Credit quality indicators
Total loans	2,581,253	2,695,176
Originated | Personal Banking | Residential mortgage loans | Pass
Credit quality indicators
Total loans	2,564,988	2,680,562
Originated | Personal Banking | Residential mortgage loans | Special mention
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Residential mortgage loans | Substandard
Credit quality indicators
Total loans	16,265	13,274
Originated | Personal Banking | Residential mortgage loans | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Residential mortgage loans | Loss
Credit quality indicators
Total loans	0	1,340
Originated | Personal Banking | Home equity loans
Credit quality indicators
Total loans	1,026,315	1,055,907
Originated | Personal Banking | Home equity loans | Pass
Credit quality indicators
Total loans	1,018,898	1,048,397
Originated | Personal Banking | Home equity loans | Special mention
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Home equity loans | Substandard
Credit quality indicators
Total loans	7,417	7,510
Originated | Personal Banking | Home equity loans | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Home equity loans | Loss
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Consumer loans
Credit quality indicators
Total loans	477,045	317,633
Originated | Personal Banking | Consumer loans | Pass
Credit quality indicators
Total loans	473,950	315,159
Originated | Personal Banking | Consumer loans | Special mention
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Consumer loans | Substandard
Credit quality indicators
Total loans	3,095	2,474
Originated | Personal Banking | Consumer loans | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Consumer loans | Loss
Credit quality indicators
Total loans	0	0
Originated | Commercial Banking
Credit quality indicators
Total loans	2,427,458	2,296,565
Originated | Commercial Banking | Pass
Credit quality indicators
Total loans	2,223,414	2,077,595
Originated | Commercial Banking | Special mention
Credit quality indicators
Total loans	51,524	69,541
Originated | Commercial Banking | Substandard
Credit quality indicators
Total loans	152,520	148,204
Originated | Commercial Banking | Doubtful
Credit quality indicators
Total loans	0	1,225
Originated | Commercial Banking | Loss
Credit quality indicators
Total loans	0	0
Originated | Commercial Banking | Commercial real estate loans
Credit quality indicators
Total loans	1,972,083	1,935,157
Originated | Commercial Banking | Commercial real estate loans | Pass
Credit quality indicators
Total loans	1,821,548	1,778,140
Originated | Commercial Banking | Commercial real estate loans | Special mention
Credit quality indicators
Total loans	36,321	46,518
Originated | Commercial Banking | Commercial real estate loans | Substandard
Credit quality indicators
Total loans	114,214	110,384
Originated | Commercial Banking | Commercial real estate loans | Doubtful
Credit quality indicators
Total loans	0	115
Originated | Commercial Banking | Commercial real estate loans | Loss
Credit quality indicators
Total loans	0	0
Originated | Commercial Banking | Commercial loans
Credit quality indicators
Total loans	455,375	361,408
Originated | Commercial Banking | Commercial loans | Pass
Credit quality indicators
Total loans	401,866	299,455
Originated | Commercial Banking | Commercial loans | Special mention
Credit quality indicators
Total loans	15,203	23,023
Originated | Commercial Banking | Commercial loans | Substandard
Credit quality indicators
Total loans	38,306	37,820
Originated | Commercial Banking | Commercial loans | Doubtful
Credit quality indicators
Total loans	0	1,110
Originated | Commercial Banking | Commercial loans | Loss
Credit quality indicators
Total loans	0	0
Acquired
Credit quality indicators
Total loans	1,045,276	856,840
Acquired | Pass
Credit quality indicators
Total loans	996,818	830,614
Acquired | Special mention
Credit quality indicators
Total loans	9,392	7,579
Acquired | Substandard
Credit quality indicators
Total loans	39,066	18,647
Acquired | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Loss
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking
Credit quality indicators
Total loans	601,884	379,571
Acquired | Personal Banking | Pass
Credit quality indicators
Total loans	596,911	377,855
Acquired | Personal Banking | Special mention
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Substandard
Credit quality indicators
Total loans	4,973	1,716
Acquired | Personal Banking | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Loss
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Residential mortgage loans
Credit quality indicators
Total loans	133,511	45,716
Acquired | Personal Banking | Residential mortgage loans | Pass
Credit quality indicators
Total loans	131,717	44,930
Acquired | Personal Banking | Residential mortgage loans | Special mention
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Residential mortgage loans | Substandard
Credit quality indicators
Total loans	1,794	786
Acquired | Personal Banking | Residential mortgage loans | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Residential mortgage loans | Loss
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Home equity loans
Credit quality indicators
Total loans	302,457	131,199
Acquired | Personal Banking | Home equity loans | Pass
Credit quality indicators
Total loans	300,100	130,338
Acquired | Personal Banking | Home equity loans | Special mention
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Home equity loans | Substandard
Credit quality indicators
Total loans	2,357	861
Acquired | Personal Banking | Home equity loans | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Home equity loans | Loss
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Consumer loans
Credit quality indicators
Total loans	165,916	202,656
Acquired | Personal Banking | Consumer loans | Pass
Credit quality indicators
Total loans	165,094	202,587
Acquired | Personal Banking | Consumer loans | Special mention
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Consumer loans | Substandard
Credit quality indicators
Total loans	822	69
Acquired | Personal Banking | Consumer loans | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Consumer loans | Loss
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking
Credit quality indicators
Total loans	443,392	477,269
Acquired | Commercial Banking | Pass
Credit quality indicators
Total loans	399,907	452,759
Acquired | Commercial Banking | Special mention
Credit quality indicators
Total loans	9,392	7,579
Acquired | Commercial Banking | Substandard
Credit quality indicators
Total loans	34,093	16,931
Acquired | Commercial Banking | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking | Loss
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking | Commercial real estate loans
Credit quality indicators
Total loans	370,006	416,277
Acquired | Commercial Banking | Commercial real estate loans | Pass
Credit quality indicators
Total loans	331,780	392,811
Acquired | Commercial Banking | Commercial real estate loans | Special mention
Credit quality indicators
Total loans	7,403	6,872
Acquired | Commercial Banking | Commercial real estate loans | Substandard
Credit quality indicators
Total loans	30,823	16,594
Acquired | Commercial Banking | Commercial real estate loans | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking | Commercial real estate loans | Loss
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking | Commercial loans
Credit quality indicators
Total loans	73,386	60,992
Acquired | Commercial Banking | Commercial loans | Pass
Credit quality indicators
Total loans	68,127	59,948
Acquired | Commercial Banking | Commercial loans | Special mention
Credit quality indicators
Total loans	1,989	707
Acquired | Commercial Banking | Commercial loans | Substandard
Credit quality indicators
Total loans	3,270	337
Acquired | Commercial Banking | Commercial loans | Doubtful
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking | Commercial loans | Loss
Credit quality indicators
Total loans	$ 0	$ 0

Loans Receivable and Allowanc80

Loans Receivable and Allowance for Loan Losses - Off-Balance Sheet Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	$ 977,528,000	$ 781,734,000
Recourse provisions for recovery of amounts from third parties	0	0
Loan commitments
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	109,032,000	186,731,000
Outstanding loan commitments for fixed rate loans	51,000,000
Outstanding loan commitments for adjustable rate loans	58,000,000
Undisbursed lines of credit
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	843,457,000	562,284,000
Standby letters of credit
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	25,039,000	32,719,000
Maximum potential amount of future payments	25,000,000
Maximum potential amount of future payments fully collateralized	16,300,000
Liability recognized for the obligations	$ 178,000	$ 1,300,000

Accrued Interest Receivable (De

Accrued Interest Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Interest Receivable and Other Assets [Abstract]
Investment securities	$ 1,613	$ 1,852
Mortgage-backed securities	910	960
Loans receivable	19,176	18,260
Accrued interest receivable	$ 21,699	$ 21,072

Federal Home Loan Bank Stock (D

Federal Home Loan Bank Stock (Details) - Federal Home Loan Bank of Pittsburgh $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)capital_stock	Dec. 31, 2015USD ($)
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Number of subclasses of capital stock required to invest in for membership | capital_stock	2
Dividend received on capital stock | $	$ 1.4	$ 2.8
Subclass B-1
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Investment in capital stock of FHLB, at cost, as a percent of member asset value, as defined by FHLB	0.10%
Subclass B-1 | Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Investment in capital stock of FHLB, at cost, as a percent of member asset value, as defined by FHLB	0.05%
Subclass B-1 | Maximum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Investment in capital stock of FHLB, at cost, as a percent of member asset value, as defined by FHLB	1.00%
Subclass B-2
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Investment in capital stock of FHLB, at cost, as a percent of borrowings outstanding	4.00%
Investment in capital stock of FHLB, at cost, as a percent of acquired member assets	4.00%
Investment in capital stock of FHLB, at cost, as a percent of certain letters of credit	0.75%
Investment in capital stock of FHLB, at cost, as a percent of outstanding advance commitments settling more than 30 days after trade	0.00%
Subclass B-2 | Minimum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Investment in capital stock of FHLB, at cost, as a percent of borrowings outstanding	2.00%
Investment in capital stock of FHLB, at cost, as a percent of acquired member assets	0.00%
Investment in capital stock of FHLB, at cost, as a percent of certain letters of credit	0.00%
Investment in capital stock of FHLB, at cost, as a percent of outstanding advance commitments settling more than 30 days after trade	0.00%
Subclass B-2 | Maximum
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Investment in capital stock of FHLB, at cost, as a percent of borrowings outstanding	6.00%
Investment in capital stock of FHLB, at cost, as a percent of acquired member assets	6.00%
Investment in capital stock of FHLB, at cost, as a percent of certain letters of credit	4.00%
Investment in capital stock of FHLB, at cost, as a percent of outstanding advance commitments settling more than 30 days after trade	6.00%

Premises and Equipment - By Maj

Premises and Equipment - By Major Classification (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Premises and Equipment
Total, at cost	$ 317,641	$ 311,075
Less accumulated depreciation and amortization	(156,456)	(156,724)
Premises and equipment, net	161,185	154,351
Depreciation and amortization expense	13,700	13,300	$ 12,000
Land and land improvements
Premises and Equipment
Total, at cost	21,229	23,257
Office buildings and improvements
Premises and Equipment
Total, at cost	156,162	153,003
Furniture, fixtures and equipment
Premises and Equipment
Total, at cost	120,391	115,576
Leasehold improvements
Premises and Equipment
Total, at cost	$ 19,859	$ 19,239

Premises and Equipment - Minimu

Premises and Equipment - Minimum Annual Rentals by Fiscal Year (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Minimum annual rentals
2,017	$ 4,846
2,018	3,697
2,019	2,579
2,020	2,015
2,021	1,596
Thereafter	5,595
Total	20,328
Rental expense	$ 5,300	$ 4,600	$ 4,400

Goodwill and Other Intangible85

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Amortizable intangible assets:
Amortization expense	$ 4,259	$ 1,688	$ 1,323
Estimated amortization expense
For the year ending December 31, 2017	6,764
For the year ending December 31, 2018	5,848
For the year ending December 31, 2019	4,933
For the year ending December 31, 2020	4,017
For the year ending December 31, 2021	3,188
Core Deposits
Amortizable intangible assets:
Intangible asset - gross	37,953	30,578
Acquisitions	25,732	7,375
Less: accumulated amortization	(34,378)	(31,192)
Intangible asset - net	29,307	6,761
Customer and Contract
Amortizable intangible assets:
Intangible asset - gross	8,496	8,234
Acquisitions	1,978	262
Less: accumulated amortization	(7,348)	(6,275)
Intangible asset - net	$ 3,126	$ 2,221

Goodwill and Other Intangible86

Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Goodwill
Goodwill impaired	$ 0	$ 0
Changes in the carrying amount of goodwill
Balance at the beginning of the period	261,736,000	175,323,000
Balance at the end of the period	307,420,000	261,736,000
Community Banks
Changes in the carrying amount of goodwill
Balance at the beginning of the period	260,123,000	173,710,000
Balance at the end of the period	305,807,000	260,123,000
Consumer Finance
Changes in the carrying amount of goodwill
Balance at the beginning of the period	1,613,000	1,613,000
Balance at the end of the period	1,613,000	1,613,000
LNB
Changes in the carrying amount of goodwill
Goodwill acquired		86,238,000
LNB | Community Banks
Changes in the carrying amount of goodwill
Goodwill acquired		86,238,000
LNB | Consumer Finance
Changes in the carrying amount of goodwill
Goodwill acquired		0
Petruso Insurance Agency
Changes in the carrying amount of goodwill
Goodwill acquired		175,000
Petruso Insurance Agency | Community Banks
Changes in the carrying amount of goodwill
Goodwill acquired		175,000
Petruso Insurance Agency | Consumer Finance
Changes in the carrying amount of goodwill
Goodwill acquired		$ 0
FNFG
Changes in the carrying amount of goodwill
Goodwill acquired	45,167,000
FNFG | Community Banks
Changes in the carrying amount of goodwill
Goodwill acquired	45,167,000
FNFG | Consumer Finance
Changes in the carrying amount of goodwill
Goodwill acquired	0
Best Insurance Agency
Changes in the carrying amount of goodwill
Goodwill acquired	404,000
Best Insurance Agency | Community Banks
Changes in the carrying amount of goodwill
Goodwill acquired	404,000
Best Insurance Agency | Consumer Finance
Changes in the carrying amount of goodwill
Goodwill acquired	0
Winan Insurance Agency
Changes in the carrying amount of goodwill
Goodwill acquired	113,000
Winan Insurance Agency | Community Banks
Changes in the carrying amount of goodwill
Goodwill acquired	113,000
Winan Insurance Agency | Consumer Finance
Changes in the carrying amount of goodwill
Goodwill acquired	$ 0

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Deposits [Abstract]
Savings deposits	$ 1,622,879	$ 1,386,017
Interest-bearing demand deposits	1,428,317	1,080,086
Noninterest-bearing demand deposits	1,448,972	1,177,256
Money market demand accounts	1,841,567	1,274,504
Time deposits	1,540,586	1,694,718
Total deposits	7,882,321	6,612,581
Aggregate amount of certificates of deposit with a minimum denomination of $100,000	451,600	518,700
Deposits in accounts exceeding $250,000	1,580,000
Contractual maturity of the certificate accounts
Due within 12 months	836,525	929,351
Due between 12 and 24 months	311,976	448,497
Due between 24 and 36 months	153,708	205,635
Due between 36 and 48 months	90,777	21,414
Due between 48 and 60 months	134,687	78,796
After 60 months	12,913	11,025
Total time deposits	1,540,586	1,694,718
Interest expense incurred on deposits
Savings deposits	3,218	3,387	$ 3,286
Interest-bearing demand deposits	462	568	587
Money market demand accounts	3,621	3,222	3,174
Time deposits	16,164	16,878	18,275
Total interest expense	$ 23,465	$ 24,055	$ 25,322

Borrowed Funds (Details)

Borrowed Funds (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Total borrowed funds, Amount	$ 142,899,000	$ 975,007,000
Term notes payable to the FHLB of Pittsburgh:
Debt Instrument [Line Items]
Due within one year, Amount	0	145,343,000
Due between one and two years, Amount	0	125,000,000
Due between two and three years, Amount	0	140,000,000
Due between three and four years, Amount	0	125,000,000
Due between four and five years, Amount	0	95,000,000
Due between five and ten years, Amount	0	120,000,000
Total borrowed funds, Amount	$ 0	$ 750,343,000
Due within one year, Average rate	0.00%	3.24%
Due between one and two years, Average rate	0.00%	3.68%
Due between two and three years, Average rate	0.00%	3.73%
Due between three and four years, Average rate	0.00%	4.32%
Due between four and five years, Average rate	0.00%	3.65%
Due between five and ten years, Average rate	0.00%	3.68%
Revolving line of credit, FHLB of Pittsburgh
Debt Instrument [Line Items]
Revolving line of credit, FHLB of Pittsburgh, Amount	$ 0	$ 106,000,000
Revolving line of credit, FHLB of Pittsburgh, Average rate	0.00%	0.43%
Maximum commitment	$ 150,000,000
Collateralized borrowings, due within one year
Debt Instrument [Line Items]
Due within one year, Amount	$ 142,899,000	$ 118,664,000
Due within one year, Average rate	0.17%	0.22%
Average amount of agreements outstanding	$ 141,600,000	$ 144,700,000	$ 155,700,000
Maximum amount of outstanding security repurchase agreement	$ 158,400,000	$ 166,400,000	$ 174,200,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Allocation of total income tax
Income before income taxes	$ 12,361	$ 4,697	$ (3,491)	$ 8,081	$ 8,684	$ 5,238	$ 7,213	$ 6,825	$ 6,190	$ 5,926	$ 4,435	$ 5,244	$ 21,648	$ 27,960	$ 21,795
Shareholders’ equity for unrealized (loss)/ gain on securities available-for-sale													(1,871)	(85)	4,286
Shareholders’ equity for tax benefit for excess of fair value above cost of stock benefit plans													(1,425)	(332)	(945)
Shareholders’ equity for pension adjustment													(2,455)	(848)	(12,985)
Shareholders’ equity for swap fair value adjustment													539	699	618
Unallocated income tax													16,436	27,394	12,769
Income tax expense applicable to income before taxes
Current													18,914	21,670	13,200
Deferred													2,734	6,290	8,595
Total provision for income taxes	12,361	$ 4,697	$ (3,491)	$ 8,081	8,684	$ 5,238	$ 7,213	$ 6,825	$ 6,190	$ 5,926	$ 4,435	$ 5,244	$ 21,648	$ 27,960	$ 21,795
Reconciliation of the expected federal statutory income tax rate to the effective rate
Expected tax rate (as a percent)													35.00%	35.00%	35.00%
Tax-exempt interest income (as a percent)													(3.30%)	(3.00%)	(4.10%)
State income tax, net of federal benefit (as a percent)													1.20%	2.90%	1.70%
Bank-owned life insurance (as a percent)													(2.60%)	(1.70%)	(1.80%)
Dividends on stock plans (as a percent)													(2.00%)	(0.80%)	(4.00%)
Low income housing and historic tax credits (as a percent)													(1.00%)	(1.40%)	(0.90%)
Non-deductible acquisition expense (as a percent)													0.00%	0.50%	0.00%
Effective Income Tax Rate Reconciliation, Employee Stock Ownership Plan Termination													3.40%	0.00%	0.00%
Other (as a percent)													(0.30%)	0.10%	0.10%
Effective tax rate (as a percent)													30.40%	31.60%	26.00%
Deferred tax assets:
Deferred fee income	187				189								$ 187	$ 189
Deferred compensation expense	2,893				3,717								2,893	3,717
Bad debts	18,823				19,478								18,823	19,478
Other reserves	1,823				0								1,823	0
Accrued postretirement benefit cost	641				644								641	644
Stock benefit plans	1,085				1,626								1,085	1,626
Writedown of investment securities	2,875				2,994								2,875	2,994
Accrued expenses	348				228								348	228
Pension and postretirement benefits	18,491				16,035								18,491	16,035
Unrealized loss on the fair value of derivatives	958				1,496								958	1,496
Purchase accounting	1,215				2,236								1,215	2,236
Other	153				325								153	325
Total deferred tax assets	49,492				48,968								49,492	48,968
Deferred tax liabilities:
Pension expense	8,689				7,557								8,689	7,557
Unrealized gain on the fair value of securities available-for-sale	252				2,122								252	2,122
Intangible assets	21,927				23,003								21,927	23,003
Mortgage servicing rights	1,559				120								1,559	120
Fixed assets	8,107				8,731								8,107	8,731
Other	635				460								635	460
Total deferred tax liabilities	41,169				41,993								41,169	41,993
Net deferred tax asset	$ 8,323				$ 6,975								$ 8,323	$ 6,975

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Valuation allowance for deferred tax assets	$ 0
Operating loss carryforwards
Deferred tax liabilities related to acquisition	8,323,000	$ 6,975,000
Unrecognized tax benefits that would impact effective tax rate if recognized	0
Accrued interest on income taxes expense	0
Accrued amount of payment of interest or penalties	0
FNFG
Operating loss carryforwards
Deferred tax liabilities related to acquisition	294,000
Domestic Tax Authority | LNB
Operating loss carryforwards
Income income tax examination, additional tax liability	0
State and Local Jurisdiction
Operating loss carryforwards
Income income tax examination, additional tax liability	$ 444,000

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Stockholders' Equity Note [Abstract]
Bad debt deductions for which no deferred income taxes have been provided	$ 39.1	$ 39.1

Earnings Per Share - Narrative

Earnings Per Share - Narrative (Details) - Stock options - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Antidilutive securities excluded from the calculation of earnings per share
Options excluded from the calculation of earnings per share (in shares)		524,250
Weighted average share price during the reporting period		$ 13.15
Average share price during the reporting period (in dollars per share)	$ 14.79	$ 12.64	$ 13.34

Earnings Per Share - Computatio

Earnings Per Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 16,193	$ 12,872	$ 15,305	$ 16,170	$ 17,345	$ 17,332	$ 12,674	$ 14,611	$ 49,667	$ 60,540	$ 61,962
Weighted average common shares outstanding													99,439,174	94,314,420	91,535,298
Dilutive potential shares due to effect of stock options													1,225,514	515,369	739,699
Total weighted average common shares and dilutive potential shares													100,664,688	94,829,789	92,274,997
Basic earnings per share (in dollars per share)	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 0.16	$ 0.14	$ 0.17	$ 0.18	$ 0.19	$ 0.19	$ 0.14	$ 0.16	$ 0.50	$ 0.64	$ 0.68
Diluted earnings per share (in dollars per share)	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 0.16	$ 0.13	$ 0.17	$ 0.18	$ 0.19	$ 0.19	$ 0.14	$ 0.16	$ 0.49	$ 0.64	$ 0.67

Employee Benefit Plans - Pensio

Employee Benefit Plans - Pension Plans, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Defined Contribution Plan Disclosure [Line Items]
Total expense for all retirement plans	$ 5.8	$ 4.6	$ 1
Postretirement Healthcare Plan
Defined Contribution Plan Disclosure [Line Items]
Employer matching contribution	50.00%
Employee matching contribution	6.00%

Employee Benefit Plans - Compon

Employee Benefit Plans - Components of Net Periodic Pension Cost and Other Amounts Recognized In OCI (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Components of net periodic pension cost
Service cost	$ 0	$ 0	$ 0
Pension Plans
Components of net periodic pension cost
Service cost	5,496	5,721	4,138
Interest cost	6,781	6,125	5,827
Expected return on plan assets	(9,897)	(10,371)	(9,663)
Net amortization and deferral	1,388	1,375	(897)
Net periodic pension (benefit)/ cost	3,768	2,850	(595)
Changes in the defined benefit pension plans’ plan assets and benefit obligations recognized in other comprehensive income
Net loss/ (gain)	1,550	(420)	30,779
Prior service cost/ (credit)	0	0	0
Amortization of prior service cost	2,323	2,323	2,322
Total recognized in other comprehensive income	3,873	1,903	33,101
Total recognized in net periodic pension cost and other comprehensive income/ (loss)	$ 7,641	4,753	32,506
Postretirement Healthcare Plan
Employee benefit plans
Defined Benefit Plan, Requisite Service Age, Minimum	55 years
Components of net periodic pension cost
Service cost	$ 0	0
Interest cost	70	58	65
Net amortization and deferral	90	60	48
Net periodic pension (benefit)/ cost	160	118	113
Changes in the defined benefit pension plans’ plan assets and benefit obligations recognized in other comprehensive income
Net loss/ (gain)	109	273	195
Total recognized in other comprehensive income	109	273	195
Total recognized in net periodic pension cost and other comprehensive income/ (loss)	270	$ 391	$ 308
Estimated net loss for the postretirement healthcare benefit plan that will be amortized from accumulated other comprehensive income into net periodic benefit cost over the next year	$ 108

Employee Benefit Plans - Define

Employee Benefit Plans - Defined Benefit Pension Plans' Funded Status (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Change in benefit obligation:
Service cost	$ 0	$ 0	$ 0
Pension Plans
Estimated net loss and prior service cost that will be amortized from accumulated other comprehensive income into net periodic cost over the next year
Estimated net loss that will be amortized from accumulated other comprehensive income into net periodic cost over the next year	3,600,000
Prior service credit that will be amortized from accumulated other comprehensive income into net periodic cost over the next year	(2,300,000)
Change in benefit obligation:
Benefit obligation at beginning of year	162,133,000	159,587,000
Service cost	5,496,000	5,721,000	4,138,000
Interest cost	6,781,000	6,125,000	5,827,000
Acquisition	0	5,662,000
Actuarial loss	4,267,000	(9,357,000)
Benefits paid	(6,469,000)	(5,605,000)
Benefit obligation at end of year	172,208,000	162,133,000	159,587,000
Change in plan assets:
Fair value of plan assets at beginning of year	143,655,000	140,183,000
Actual return on plan assets	8,903,000	(2,264,000)
Employer contributions	6,536,000	6,460,000
Acquisition	0	4,881,000
Benefits paid	(6,469,000)	(5,605,000)
Fair value of plan assets at end of period	152,625,000	143,655,000	$ 140,183,000
Funded status at end of year	$ (19,583,000)	$ (18,478,000)
Assumptions used to develop the net periodic pension cost
Discount rate	4.25%	3.89%	4.86%
Expected long-term rate of return on assets	7.00%	7.50%	7.50%
Rate of increase in compensation levels	3.00%	3.00%	3.00%
Assumptions used to determine benefit obligations
Discount rate	4.06%	4.25%	3.89%
Expected long-term rate of return on assets	7.00%	7.00%	7.50%
Rate of increase in compensation levels	3.00%	3.00%	3.00%
Postretirement Healthcare Plan
Change in benefit obligation:
Benefit obligation at beginning of year	$ 1,737,000	$ 1,565,000
Service cost	0	0
Interest cost	70,000	58,000	$ 65,000
Actuarial loss	200,000	333,000
Benefits paid	(228,000)	(219,000)
Benefit obligation at end of year	1,779,000	1,737,000	1,565,000
Change in plan assets:
Fair value of plan assets at beginning of year	0	0
Employer contributions	228,000	219,000
Benefits paid	(228,000)	(219,000)
Fair value of plan assets at end of period	0	0	$ 0
Funded status at end of year	$ (1,779,000)	$ (1,737,000)
Assumptions used to develop the net periodic pension cost
Discount rate	4.25%	3.89%	4.86%
Monthly cost of healthcare insurance per beneficiary	$ 539	$ 470	$ 384
Annual rate of increase in healthcare costs	4.00%	4.00%	4.00%

Employee Benefit Plans - Fair V

Employee Benefit Plans - Fair Value of Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plans
Employee benefit plans
Accumulated benefit obligation for funded defined benefit pension plan	$ 165,900	$ 155,900	$ 153,900
Accumulated benefit obligation for unfunded defined benefit pension plan	6,300	6,300	5,600
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation	172,208	162,133	159,587
Accumulated benefit obligation	172,208	162,133
Fair value of plan assets	$ 152,625	$ 143,655	140,183
Target allocation of any one stock, maximum (as a percent)	10.00%
Maximum average maturity of bond portfolio	10 years
Target Allocation
Total (as a percent)	100.00%	100.00%
Pension Plans | Debt securities
Accumulated benefit obligation in excess of plan assets
Target Allocation of securities, minimum (as a percent)	20.00%	20.00%
Target Allocation of securities, maximum (as a percent)	50.00%	50.00%
Target Allocation
Target Allocation of securities, minimum (as a percent)	20.00%	20.00%
Target Allocation of securities, maximum (as a percent)	50.00%	50.00%
Total (as a percent)	23.00%	20.00%
Pension Plans | Equity securities
Accumulated benefit obligation in excess of plan assets
Target Allocation of securities, minimum (as a percent)	30.00%	30.00%
Target Allocation of securities, maximum (as a percent)	60.00%	60.00%
Target Allocation
Target Allocation of securities, minimum (as a percent)	30.00%	30.00%
Target Allocation of securities, maximum (as a percent)	60.00%	60.00%
Total (as a percent)	72.00%	69.00%
Pension Plans | Other
Accumulated benefit obligation in excess of plan assets
Target Allocation of securities, minimum (as a percent)	5.00%	5.00%
Target Allocation of securities, maximum (as a percent)	50.00%	50.00%
Target Allocation
Target Allocation of securities, minimum (as a percent)	5.00%	5.00%
Target Allocation of securities, maximum (as a percent)	50.00%	50.00%
Total (as a percent)	5.00%	11.00%
Pension Plans | Minimum
Accumulated benefit obligation in excess of plan assets
Anticipated contribution	$ 4,000
Pension Plans | Maximum
Accumulated benefit obligation in excess of plan assets
Anticipated contribution	8,000
Postretirement Healthcare Plan
Accumulated benefit obligation in excess of plan assets
Projected benefit obligation	1,779	$ 1,737	1,565
Accumulated benefit obligation	1,779	1,737
Fair value of plan assets	$ 0	$ 0	$ 0

Employee Benefit Plans - Pens98

Employee Benefit Plans - Pension Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Pension Plans
Employee benefit plans
Fair value of plan assets	$ 152,625	$ 143,655	$ 140,183
Benefits expected to be paid in each year
2,017	5,400
2,018	5,700
2,019	6,400
2,020	6,600
2,021	6,900
2021 to 2025	34,900
Pension Plans | Level 1 | Mutual funds — debt
Employee benefit plans
Fair value of plan assets	35,224	28,316
Pension Plans | Level 1 | Mutual funds — equity
Employee benefit plans
Fair value of plan assets	110,078	98,517
Pension Plans | Level 1 | Cash and cash equivalents
Employee benefit plans
Fair value of plan assets	7,322	16,822
Postretirement Healthcare Plan
Employee benefit plans
Fair value of plan assets	$ 0	$ 0	$ 0
Effect of 1-percent increase in the assumed health care cost trend rates
Effect of 1-percent increase on health care cost percentage	5.00%
Annual rate of increase in healthcare costs	4.00%	4.00%	4.00%
Effect of 1-percent increase in assumed health care cost trend rates on interest cost in current period	$ 11
Effect of 1-percent increase in assumed health care cost trend rates on postretirement benefit obligation	$ 68

Employee Benefit Plans - Employ

Employee Benefit Plans - Employee Stock Ownership Plan (Details) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Employee stock ownership plan
Employee Stock Ownership Plan (ESOP), number of unallocated shares distributed to employees (in shares)	401,356
Compensation expense		$ 6,300
Employee Stock Ownership Plan
Employee stock ownership plan
Compensation expense		$ 6,300	$ 335	$ 3,000
Stock options
Employee stock ownership plan
Employee Stock Ownership Plan (ESOP), number of shares retired (in shares)	1,366,574

Employee Benefit Plans - Share-

Employee Benefit Plans - Share-Based Awards (Details) - USD ($) $ / shares in Units, $ in Millions	May 18, 2016	May 17, 2016	May 20, 2015	May 19, 2015	May 21, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Apr. 20, 2011
Restricted common shares
Recognition and Retention Plan and Stock Option Plans
Weighted average grant date fair value of shares issued (in dollars per share)	$ 14.51		$ 12.31		$ 13.22
Market value of shares issued	$ 4.9		$ 3.8		$ 3.6
Number of shares forfeited						49,776
Vesting period						10 years
Restricted common shares | 2011 Equity Incentive Plan
Recognition and Retention Plan and Stock Option Plans
Number of shares authorized									2,806,233
Number of shares forfeited						309,554
Restricted common shares | 2013 issuance
Recognition and Retention Plan and Stock Option Plans
Percentage of granted awards which will vest						30.00%
Restricted common shares | 2014 issuance
Recognition and Retention Plan and Stock Option Plans
Percentage of granted awards which will vest						20.00%
Restricted common shares | 2015 issuance
Recognition and Retention Plan and Stock Option Plans
Percentage of granted awards which will vest						10.00%
Stock options
Recognition and Retention Plan and Stock Option Plans
Vesting period						10 years
Exercise period						10 years
Number
Balance at beginning of year (in shares)						6,306,496	6,402,407	6,816,294
Granted (in shares)						725,400	665,370	592,550
Exercised (in shares)						(1,081,072)	(474,253)	(745,419)
Forfeited/ expired (in shares)						(146,719)	(287,028)	(261,018)
Balance at end of year (in shares)						5,804,105	6,306,496	6,402,407
Exercisable at end of year (in shares)						3,035,718	3,431,113	3,333,942
Weighted average exercise price
Balance at beginning of year (in dollars per share)						$ 11.81	$ 11.65	$ 11.46
Granted (in dollars per share)		$ 14.15		$ 12.37		14.15	12.37	13.15
Exercised (in dollars per share)						11.01	10.27	10.86
Forfeited (in dollars per share)						12.71	12.26	11.71
Balance at end of year (in dollars per share)						12.25	11.81	11.65
Exercisable at end of year (in dollars per share)						11.71	11.42	11.20
Additional disclosure
Weighted average fair value of options at grant date (in dollars per share)					$ 13.15	$ 1.52	$ 1.14	$ 1.45
Total intrinsic value of options exercised						$ 5.1	$ 1.2	$ 2.3
Aggregate intrinsic value of all options expected to vest						14.4
Aggregate intrinsic value of all options fully vested						$ 19.2
Stock options | 2011 Equity Incentive Plan
Recognition and Retention Plan and Stock Option Plans
Number of shares authorized									7,015,583
Director | Restricted common shares
Recognition and Retention Plan and Stock Option Plans
Number of shares issued	24,300		24,300		21,600	24,300
Director | Stock options
Number
Granted (in shares)		64,800		64,800	57,600	64,800
Employees | Restricted common shares
Recognition and Retention Plan and Stock Option Plans
Number of shares issued	310,160		282,050		251,030	310,160
Employees | Stock options
Number
Granted (in shares)		660,600		660,570	534,950	660,600

Employee Benefit Plans - Number

Employee Benefit Plans - Number of Options Outstanding and Exercisable and Weighted Average Remaining Life of All Option Grants (Details)	12 Months Ended
	Dec. 31, 2016$ / sharesshares
Exercise price $7.48
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 7.48
Options outstanding:
Number of options (in shares)	195,902
Weighted average remaining contract life (years)	2 years 3 months
Options exercisable:
Number of options (in shares)	195,902
Weighted average remaining term - vested (years)	2 years 3 months
Exercise price $9.79
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 9.79
Options outstanding:
Number of options (in shares)	207,156
Weighted average remaining contract life (years)	2 years
Options exercisable:
Number of options (in shares)	207,156
Weighted average remaining term - vested (years)	2 years
Exercise price $11.12
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 11.12
Options outstanding:
Number of options (in shares)	125,448
Weighted average remaining contract life (years)	1 year 3 months
Options exercisable:
Number of options (in shares)	125,448
Weighted average remaining term - vested (years)	1 year 3 months
Exercise price $11.49
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 11.49
Options outstanding:
Number of options (in shares)	320,045
Weighted average remaining contract life (years)	3 years 3 months
Options exercisable:
Number of options (in shares)	298,473
Weighted average remaining term - vested (years)	3 years 3 months
Exercise price $11.51
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 11.51
Options outstanding:
Number of options (in shares)	47,557
Weighted average remaining contract life (years)	3 months
Options exercisable:
Number of options (in shares)	47,557
Weighted average remaining term - vested (years)	3 months
Exercise price $11.70
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 11.70
Options outstanding:
Number of options (in shares)	432,941
Weighted average remaining contract life (years)	5 years 6 months
Options exercisable:
Number of options (in shares)	226,915
Weighted average remaining term - vested (years)	5 years 6 months
Exercise price $12.12
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 12.12
Options outstanding:
Number of options (in shares)	398,478
Weighted average remaining contract life (years)	4 years 3 months
Options exercisable:
Number of options (in shares)	309,987
Weighted average remaining term - vested (years)	4 years 3 months
Exercise price $12.17
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 12.17
Options outstanding:
Number of options (in shares)	21,500
Weighted average remaining contract life (years)	4 years 6 months
Options exercisable:
Number of options (in shares)	12,931
Weighted average remaining term - vested (years)	4 years 6 months
Exercise price $12.32
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 12.32
Options outstanding:
Number of options (in shares)	1,815,615
Weighted average remaining contract life (years)	4 years 6 months
Options exercisable:
Number of options (in shares)	1,151,004
Weighted average remaining term - vested (years)	4 years 6 months
Exercise price $12.37
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 12.37
Options outstanding:
Number of options (in shares)	577,405
Weighted average remaining contract life (years)	8 years 6 months
Options exercisable:
Number of options (in shares)	81,759
Weighted average remaining term - vested (years)	8 years 6 months
Exercise price $12.44
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 12.44
Options outstanding:
Number of options (in shares)	474,467
Weighted average remaining contract life (years)	6 years 6 months
Options exercisable:
Number of options (in shares)	199,534
Weighted average remaining term - vested (years)	6 years 6 months
Exercise Price $13.15
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 13.15
Options outstanding:
Number of options (in shares)	487,865
Weighted average remaining contract life (years)	7 years 6 months
Options exercisable:
Number of options (in shares)	132,186
Weighted average remaining term - vested (years)	7 years 6 months
Exercise price $14.15
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 14.15
Options outstanding:
Number of options (in shares)	699,726
Weighted average remaining contract life (years)	9 years 6 months
Options exercisable:
Number of options (in shares)	46,866
Weighted average remaining term - vested (years)	9 years 6 months
$12.25
Outstanding and exercisable options
Exercise price (in dollars per share) | $ / shares	$ 12.25
Options outstanding:
Number of options (in shares)	5,804,105
Weighted average remaining contract life (years)	5 years 7 months 2 days
Options exercisable:
Number of options (in shares)	3,035,718
Weighted average remaining term - vested (years)	4 years 18 days

Disclosures About Fair Value102

Disclosures About Fair Value of Financial Instruments - Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Significant unrealized appreciation or depreciation in financial instruments	$ 0	$ 0
Financial assets:
Securities available-for-sale	826,200,000	874,405,000
Securities held-to-maturity	20,426,000	32,552,000
Accrued interest receivable	21,699,000	21,072,000
Financial liabilities:
Borrowed funds	142,899,000	975,007,000
Junior subordinated debentures	111,213,000	111,213,000
Assets transferred between Level 1 and Level 2	0
Level 1
Financial assets:
Cash and cash equivalents	389,867,000	167,408,000
Securities available-for-sale	4,440,000	1,894,000
Securities held-to-maturity	0	0
Loans receivable, net	9,625,000	0
Accrued interest receivable	21,699,000	21,072,000
FHLB Stock	0	0
Total assets and liabilities	425,631,000	190,374,000
Financial liabilities:
Savings and checking accounts	6,341,735,000	4,917,863,000
Time deposits	0	0
Borrowed funds	142,899,000	118,664,000
Junior subordinated debentures	0	0
Cash flow hedges - swaps	0	0
Accrued interest payable	643,000	1,993,000
Total financial liabilities	6,485,277,000	5,038,520,000
Level 2
Financial assets:
Cash and cash equivalents	0	0
Securities available-for-sale	812,394,000	863,556,000
Securities held-to-maturity	20,426,000	32,552,000
Loans receivable, net	0	0
Accrued interest receivable	0	0
FHLB Stock	0	0
Total assets and liabilities	832,820,000	896,108,000
Financial liabilities:
Savings and checking accounts	0	0
Time deposits	0	0
Borrowed funds	0	0
Junior subordinated debentures	0	0
Cash flow hedges - swaps	2,736,000	4,276,000
Accrued interest payable	0	0
Total financial liabilities	2,736,000	4,276,000
Level 3
Financial assets:
Cash and cash equivalents	0	0
Securities available-for-sale	9,366,000	8,955,000
Securities held-to-maturity	0	0
Loans receivable, net	7,869,190,000	7,482,431,000
Accrued interest receivable	0	0
FHLB Stock	0	0
Total assets and liabilities	7,878,556,000	7,491,386,000
Financial liabilities:
Savings and checking accounts	0	0
Time deposits	1,626,434,000	1,710,388,000
Borrowed funds	0	879,863,000
Junior subordinated debentures	113,313,000	115,268,000
Cash flow hedges - swaps	0	0
Accrued interest payable	0	0
Total financial liabilities	1,739,747,000	2,705,519,000
Carrying amount
Financial assets:
Cash and cash equivalents	389,867,000	167,408,000
Securities available-for-sale	826,200,000	874,405,000
Securities held-to-maturity	19,978,000	31,689,000
Loans receivable, net	7,496,408,000	7,159,449,000
Accrued interest receivable	21,699,000	21,072,000
FHLB Stock	7,390,000	40,903,000
Total assets and liabilities	8,761,542,000	8,294,926,000
Financial liabilities:
Savings and checking accounts	6,341,735,000	4,917,863,000
Time deposits	1,540,586,000	1,694,718,000
Borrowed funds	142,899,000	975,007,000
Junior subordinated debentures	111,213,000	111,213,000
Cash flow hedges - swaps	2,736,000	4,276,000
Accrued interest payable	643,000	1,993,000
Total financial liabilities	8,139,812,000	7,705,070,000
Estimated fair value
Financial assets:
Cash and cash equivalents	389,867,000	167,408,000
Securities available-for-sale	826,200,000	874,405,000
Securities held-to-maturity	20,426,000	32,552,000
Loans receivable, net	7,878,815,000	7,482,431,000
Accrued interest receivable	21,699,000	21,072,000
FHLB Stock	7,390,000	40,903,000
Total assets and liabilities	9,144,397,000	8,618,771,000
Financial liabilities:
Savings and checking accounts	6,341,735,000	4,917,863,000
Time deposits	1,626,434,000	1,710,388,000
Borrowed funds	142,899,000	998,527,000
Junior subordinated debentures	113,313,000	115,268,000
Cash flow hedges - swaps	2,736,000	4,276,000
Accrued interest payable	643,000	1,993,000
Total financial liabilities	$ 8,227,760,000	$ 7,748,315,000

Disclosures About Fair Value103

Disclosures About Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	$ 826,200	$ 874,405
Level 1
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	4,440	1,894
Cash flow hedges - swaps	0	0
Total assets and liabilities	425,631	190,374
Level 2
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	812,394	863,556
Cash flow hedges - swaps	(2,736)	(4,276)
Total assets and liabilities	832,820	896,108
Level 3
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	9,366	8,955
Cash flow hedges - swaps	0	0
Total assets and liabilities	7,878,556	7,491,386
Measured on recurring basis
Assets and liabilities measured at fair value on a recurring basis
Total assets and liabilities	823,464	870,129
Measured on recurring basis | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	4,440	1,894
Measured on recurring basis | Debt securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	374,226	393,794
Measured on recurring basis | Debt securities | U.S. Government and agencies
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	6	11
Measured on recurring basis | Debt securities | Government sponsored enterprises
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	294,170	294,440
Measured on recurring basis | Debt securities | States and political subdivisions
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	63,070	82,868
Measured on recurring basis | Debt securities | Corporate
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	16,980	16,475
Measured on recurring basis | Mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	447,534	478,717
Measured on recurring basis | Residential mortgage-backed securities | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	30,883	27,082
Measured on recurring basis | Residential mortgage-backed securities | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	106,578	99,170
Measured on recurring basis | Residential mortgage-backed securities | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	82,115	50,369
Measured on recurring basis | Residential mortgage-backed securities | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	579	606
Measured on recurring basis | Collateralized mortgage obligations | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	6,287	10,669
Measured on recurring basis | Collateralized mortgage obligations | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	95,186	122,528
Measured on recurring basis | Collateralized mortgage obligations | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	119,197	157,378
Measured on recurring basis | Collateralized mortgage obligations | SBA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	6,608	8,166
Measured on recurring basis | Collateralized mortgage obligations | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	101	2,749
Measured on recurring basis | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - swaps	(2,736)	(4,276)
Measured on recurring basis | Level 1
Assets and liabilities measured at fair value on a recurring basis
Total assets and liabilities	4,440	1,894
Measured on recurring basis | Level 1 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	4,440	1,894
Measured on recurring basis | Level 1 | Debt securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 1 | Debt securities | U.S. Government and agencies
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 1 | Debt securities | Government sponsored enterprises
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 1 | Debt securities | States and political subdivisions
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 1 | Debt securities | Corporate
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 1 | Mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Residential mortgage-backed securities | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Residential mortgage-backed securities | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Residential mortgage-backed securities | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Residential mortgage-backed securities | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Collateralized mortgage obligations | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Collateralized mortgage obligations | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Collateralized mortgage obligations | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Collateralized mortgage obligations | SBA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Collateralized mortgage obligations | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 1 | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - swaps	0	0
Measured on recurring basis | Level 2
Assets and liabilities measured at fair value on a recurring basis
Total assets and liabilities	809,658	859,280
Measured on recurring basis | Level 2 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 2 | Debt securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	364,860	384,839
Measured on recurring basis | Level 2 | Debt securities | U.S. Government and agencies
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	6	11
Measured on recurring basis | Level 2 | Debt securities | Government sponsored enterprises
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	294,170	294,440
Measured on recurring basis | Level 2 | Debt securities | States and political subdivisions
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	63,070	82,868
Measured on recurring basis | Level 2 | Debt securities | Corporate
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	7,614	7,520
Measured on recurring basis | Level 2 | Mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	447,534	478,717
Measured on recurring basis | Level 2 | Residential mortgage-backed securities | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	30,883	27,082
Measured on recurring basis | Level 2 | Residential mortgage-backed securities | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	106,578	99,170
Measured on recurring basis | Level 2 | Residential mortgage-backed securities | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	82,115	50,369
Measured on recurring basis | Level 2 | Residential mortgage-backed securities | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	579	606
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	6,287	10,669
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	95,186	122,528
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	119,197	157,378
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | SBA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	6,608	8,166
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	101	2,749
Measured on recurring basis | Level 2 | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - swaps	(2,736)	(4,276)
Measured on recurring basis | Level 3
Assets and liabilities measured at fair value on a recurring basis
Total assets and liabilities	9,366	8,955
Measured on recurring basis | Level 3 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 3 | Debt securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	9,366	8,955
Measured on recurring basis | Level 3 | Debt securities | U.S. Government and agencies
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 3 | Debt securities | Government sponsored enterprises
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 3 | Debt securities | States and political subdivisions
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Measured on recurring basis | Level 3 | Debt securities | Corporate
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	9,366	8,955
Measured on recurring basis | Level 3 | Mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Residential mortgage-backed securities | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Residential mortgage-backed securities | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Residential mortgage-backed securities | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Residential mortgage-backed securities | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Collateralized mortgage obligations | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Collateralized mortgage obligations | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Collateralized mortgage obligations | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Collateralized mortgage obligations | SBA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Collateralized mortgage obligations | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	0
Measured on recurring basis | Level 3 | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - swaps	$ 0	$ 0

Disclosures About Fair Value104

Disclosures About Fair Value of Financial Instruments - Reconciliation of all Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Significant Unobservable Inputs (Level 3) (Details) - Level 3 - Debt securities - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of all assets and liabilities measured at fair value on a recurring basis using significant unobservable inputs (Level 3)
Balance at the beginning of the period	$ 8,955	$ 10,597
Total net realized investment gains/ (losses) and net change in unrealized appreciation/ (depreciation):
Included in net income as OTTI	0	0
Included in other comprehensive income	411	(502)
Purchases	0	0
Sales/ calls	0	(1,140)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at the end of the period	$ 9,366	$ 8,955

Disclosures About Fair Value105

Disclosures About Fair Value of Financial Instruments - Nonrecurring Assets that had Fair Market Values Below the Carrying Amount (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	$ 47,068	$ 56,906
Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0	0
Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0	0
Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	47,068	56,906
Loans evaluated for impairment
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	41,933	48,181
Loans evaluated for impairment | Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0	0
Loans evaluated for impairment | Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0	0
Loans evaluated for impairment | Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	41,933	48,181
Mortgage servicing rights
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	246
Mortgage servicing rights | Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0
Mortgage servicing rights | Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0
Mortgage servicing rights | Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	246
Real estate owned
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	4,889	8,725
Real estate owned | Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0	0
Real estate owned | Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	0	0
Real estate owned | Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Total assets	$ 4,889	$ 8,725

Disclosures About Fair Value106

Disclosures About Fair Value of Financial Instruments - Additional Quantitative Information, Assets Measured at Fair Value, Recurring and Nonrecurring Basis, Level 3 Input (Details)	12 Months Ended
	Dec. 31, 2016USD ($)
Debt securities
Quantitative information for Level 3 Fair Value Measurements Assets
Fair value	$ 9,366,000
Debt securities | Discounted cash flow
Quantitative information for Level 3 Fair Value Measurements Assets
Default rates	1.00%
Prepayment speeds / rate	1.00%
Debt securities | Discounted cash flow | Minimum
Quantitative information for Level 3 Fair Value Measurements Assets
Discount margin	0.40%
Debt securities | Discounted cash flow | Maximum
Quantitative information for Level 3 Fair Value Measurements Assets
Discount margin	2.10%
Debt securities | Discounted cash flow | Weighted Average
Quantitative information for Level 3 Fair Value Measurements Assets
Discount margin	0.70%
Loans evaluated for impairment
Quantitative information for Level 3 Fair Value Measurements Assets
Fair value	$ 41,933,000
Loans evaluated for impairment | Discounted cash flow | Minimum
Quantitative information for Level 3 Fair Value Measurements Assets
Discount rate	3.80%
Loans evaluated for impairment | Discounted cash flow | Maximum
Quantitative information for Level 3 Fair Value Measurements Assets
Discount rate	20.00%
Loans evaluated for impairment | Discounted cash flow | Weighted Average
Quantitative information for Level 3 Fair Value Measurements Assets
Discount rate	11.00%
Loans evaluated for impairment | Appraisal Value
Quantitative information for Level 3 Fair Value Measurements Assets
Estimated costs to sell	10.00%
Real estate owned
Quantitative information for Level 3 Fair Value Measurements Assets
Fair value	$ 4,889,000
Mortgage servicing rights
Quantitative information for Level 3 Fair Value Measurements Assets
Fair value	$ 246,000
Mortgage servicing rights | Discounted cash flow
Quantitative information for Level 3 Fair Value Measurements Assets
Expected life (in months), minimum	66 months 6 days
Expected life (in months) maximum	68 months 27 days
Expected life (in months), weighted average	70 months 27 days
Annual service cost	$ 80,000
Option adjusted spread	8.00%
Mortgage servicing rights | Discounted cash flow | Minimum
Quantitative information for Level 3 Fair Value Measurements Assets
Prepayment speeds / rate	6.00%
Forward yield curve	0.60%
Mortgage servicing rights | Discounted cash flow | Maximum
Quantitative information for Level 3 Fair Value Measurements Assets
Prepayment speeds / rate	7.40%
Forward yield curve	2.20%
Mortgage servicing rights | Discounted cash flow | Weighted Average
Quantitative information for Level 3 Fair Value Measurements Assets
Prepayment speeds / rate	7.10%
Forward yield curve	1.30%

Regulatory Capital Requireme107

Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Total capital (to risk weighted assets)
Minimum capital requirements amount	0.625%
Northwest Bancshares, Inc.
Total capital (to risk weighted assets)
Actual amount	$ 1,051,582	$ 1,102,468
Actual ratio (as a percent)	14.873%	16.63%
Capital required for capital adequacy	$ 609,835	$ 530,257
Minimum capital requirements ratio (as a percent)	8.625%	8.00%
Well capitalized requirements amount	$ 751,246	$ 662,821
Well capitalized requirements ratio (as a percent)	10.625%	10.00%
Tier 1 capital (to risk weighted assets)
Actual amount	$ 990,153	$ 1,039,574
Actual ratio (as a percent)	14.004%	15.68%
Minimum capital requirements amount	$ 468,424	$ 397,693
Minimum capital requirements ratio (as a percent)	6.625%	6.00%
Well capitalized requirements amount	$ 609,835	$ 530,257
Well capitalized requirements ratio (as a percent)	8.625%	8.00%
CET 1 capital (to risk weighted assets)
Actual amount	$ 882,278	$ 931,699
Actual ratio (as a percent)	12.478%	14.06%
Minimum capital requirements amount	$ 362,366	$ 298,269
Minimum capital requirements ratio (as a percent)	5.125%	4.50%
Well capitalized requirements amount	$ 503,777	$ 430,834
Well capitalized requirements ratio (as a percent)	7.125%	6.50%
Tier 1 capital (leverage) (to average assets)
Actual amount	$ 990,153	$ 1,039,574
Actual ratio (as a percent)	10.53%	11.96%
Minimum capital requirements amount	$ 376,116	$ 347,582
Minimum capital requirements ratio (as a percent)	4.00%	4.00%
Well capitalized requirements amount	$ 470,145	$ 434,477
Well capitalized requirements ratio (as a percent)	5.00%	5.00%
Northwest Bank
Total capital (to risk weighted assets)
Actual amount	$ 961,279	$ 1,006,230
Actual ratio (as a percent)	13.609%	15.20%
Capital required for capital adequacy	$ 609,248	$ 529,498
Minimum capital requirements ratio (as a percent)	8.625%	8.00%
Well capitalized requirements amount	$ 750,523	$ 661,872
Well capitalized requirements ratio (as a percent)	10.625%	10.00%
Tier 1 capital (to risk weighted assets)
Actual amount	$ 900,328	$ 943,554
Actual ratio (as a percent)	12.746%	14.26%
Minimum capital requirements amount	$ 467,973	$ 397,123
Minimum capital requirements ratio (as a percent)	6.625%	6.00%
Well capitalized requirements amount	$ 609,248	$ 529,498
Well capitalized requirements ratio (as a percent)	8.625%	8.00%
CET 1 capital (to risk weighted assets)
Actual amount	$ 900,328	$ 943,554
Actual ratio (as a percent)	12.746%	14.26%
Minimum capital requirements amount	$ 362,017	$ 297,843
Minimum capital requirements ratio (as a percent)	5.125%	4.50%
Well capitalized requirements amount	$ 503,292	$ 430,217
Well capitalized requirements ratio (as a percent)	7.125%	6.50%
Tier 1 capital (leverage) (to average assets)
Actual amount	$ 900,328	$ 943,554
Actual ratio (as a percent)	9.585%	10.87%
Minimum capital requirements amount	$ 375,735	$ 347,063
Minimum capital requirements ratio (as a percent)	4.00%	4.00%
Well capitalized requirements amount	$ 469,669	$ 433,829
Well capitalized requirements ratio (as a percent)	5.00%	5.00%

Components of Accumulated Ot108

Components of Accumulated Other Comprehensive Income - (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	$ 1,170,663	$ 1,163,163	$ 1,062,647	$ 1,155,185
Unrealized gain on marketable securities available-for-sale
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	395	3,325	3,461	(3,233)
Fair value of interest rate swaps
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	(1,778)	(2,779)	(4,078)	(5,224)
Defined benefit pension plans
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	(26,608)	(25,081)	(23,753)	(3,443)
Accumulated other comprehensive income
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	$ (27,991)	$ (24,535)	$ (24,370)	$ (11,900)

Components of Accumulated Ot109

Components of Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive income (net of tax)
Reclassification adjustment for gains (losses) on securities, net of tax	$ 202	$ 451	$ 2,348
Income tax (expense) benefit related to (gain) loss on securities	129	289	1,501
Amortization of prior service cost (compensation and employee benefits)	872	875	(552)
Income tax expense (benefit) related to compensation and employee benefits	606	560	(335)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	1,163,163	1,062,647	1,155,185
Other comprehensive loss	(3,456)	(165)	(12,470)
Balance at end of the period	1,170,663	1,163,163	1,062,647
Unrealized gain on marketable securities available-for-sale
Accumulated other comprehensive income (net of tax)
Reclassification adjustment for gains (losses) on securities, net of tax	331	740	(3,849)
Income tax (expense) benefit related to (gain) loss on securities	(129)	(289)	1,501
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	3,325	3,461	(3,233)
Other comprehensive income/ (loss) before reclassification adjustments	(2,728)	315	9,042
Amounts reclassified from accumulated other comprehensive income (1), (2)	(202)	(451)	(2,348)
Other comprehensive loss	(2,930)	(136)	6,694
Balance at end of the period	395	3,325	3,461
Fair value of interest rate swaps
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(2,779)	(4,078)	(5,224)
Other comprehensive income/ (loss) before reclassification adjustments	1,001	1,299	1,146
Amounts reclassified from accumulated other comprehensive income (1), (2)	0	0	0
Other comprehensive loss	1,001	1,299	1,146
Balance at end of the period	(1,778)	(2,779)	(4,078)
Defined benefit pension plans
Accumulated other comprehensive income (net of tax)
Amortization of prior service cost (compensation and employee benefits)	2,323	2,323	2,323
Amortization of net loss (compensation and employee benefits)	(3,801)	(3,758)	(1,436)
Income tax expense (benefit) related to compensation and employee benefits	606	560	(335)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(25,081)	(23,753)	(3,443)
Other comprehensive income/ (loss) before reclassification adjustments	(2,399)	(2,203)	(19,758)
Amounts reclassified from accumulated other comprehensive income (1), (2)	872	875	(552)
Other comprehensive loss	(1,527)	(1,328)	(20,310)
Balance at end of the period	(26,608)	(25,081)	(23,753)
Accumulated other comprehensive income
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(24,535)	(24,370)	(11,900)
Other comprehensive income/ (loss) before reclassification adjustments	(4,126)	(589)	(9,604)
Amounts reclassified from accumulated other comprehensive income (1), (2)	670	424	(2,866)
Other comprehensive loss	(3,456)	(165)	(12,470)
Balance at end of the period	$ (27,991)	$ (24,535)	$ (24,370)

Parent Company Only Financia110

Parent Company Only Financial Statements - Condensed - Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Assets
Total cash and cash equivalents	$ 389,867	$ 167,408	$ 240,706	$ 391,905
Marketable securities available-for-sale (amortized cost of $825,552 and $868,956)	826,200	874,405
Other assets	32,194	54,670
Total assets	9,623,640	8,951,899	7,775,033
Liabilities:
Debentures payable	111,213	111,213
Other liabilities	63,373	54,207
Total liabilities	8,452,977	7,788,736
Shareholders’ equity	1,170,663	1,163,163	1,062,647	1,155,185
Total liabilities and shareholders’ equity	9,623,640	8,951,899
Parent Company
Assets
Total cash and cash equivalents	34,521	91,056	$ 110,699	$ 188,775
Marketable securities available-for-sale (amortized cost of $825,552 and $868,956)	4,413	1,884
Investment in bank subsidiary	1,193,175	1,182,308
Other assets	52,645	3,547
Total assets	1,284,754	1,278,795
Liabilities:
Debentures payable	111,213	111,213
Other liabilities	2,878	4,419
Total liabilities	114,091	115,632
Shareholders’ equity	1,170,663	1,163,163
Total liabilities and shareholders’ equity	$ 1,284,754	$ 1,278,795

Parent Company Only Financia111

Parent Company Only Financial Statements - Condensed - Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income:
Interest income	$ 90,033	$ 84,748	$ 85,555	$ 85,298	$ 85,639	$ 81,091	$ 75,970	$ 76,880	$ 76,586	$ 76,528	$ 76,987	$ 75,326	$ 345,634	$ 319,580	$ 305,427
Expense:
Other expense													13,014	9,031	9,797
Interest expense	7,091	7,454	10,008	13,746	14,486	14,150	13,792	13,899	13,982	14,187	14,214	14,204	38,299	56,327	56,587
Income before income taxes	36,855	18,894	(10,499)	26,065	24,877	18,110	22,518	22,995	23,535	23,258	17,109	19,855	71,315	88,500	83,757
Federal and state income taxes	12,361	4,697	(3,491)	8,081	8,684	5,238	7,213	6,825	6,190	5,926	4,435	5,244	21,648	27,960	21,795
Net income	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 16,193	$ 12,872	$ 15,305	$ 16,170	$ 17,345	$ 17,332	$ 12,674	$ 14,611	49,667	60,540	61,962
Parent Company
Income:
Interest income													737	1,258	1,248
Other income													709	659	3,424
Dividends from bank subsidiary													50,000	135,000	66,183
Undistributed earnings from equity investment in bank subsidiary													2,760	(70,854)	(3,261)
Total income													54,206	66,063	67,594
Expense:
Compensation and benefits													1,129	1,061	962
Other expense													561	1,356	572
Interest expense													4,560	4,926	4,691
Total expense													6,250	7,343	6,225
Income before income taxes													47,956	58,720	61,369
Federal and state income taxes													(1,711)	(1,820)	(593)
Net income													$ 49,667	$ 60,540	$ 61,962

Parent Company Only Financia112

Parent Company Only Financial Statements - Condensed - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Operating activities:
Net Income	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 16,193	$ 12,872	$ 15,305	$ 16,170	$ 17,345	$ 17,332	$ 12,674	$ 14,611	$ 49,667	$ 60,540	$ 61,962
Adjustments to reconcile net income to net cash provided by operating activities:
Noncash stock benefit plan compensation expense													10,916	5,570	5,711
Gain on sale of marketable securities													(625)	(1,037)	(4,930)
Net cash provided by operating activities													136,902	113,202	90,572
Investing activities:
Proceeds from sale of marketable securities available-for-sale													1,951	1,246	7,910
Acquisition, net of cash received													1,102,237	(61,108)	(2,792)
Net cash provided by/ (used in) investing activities													1,149,408	(88,812)	(67,995)
Financing activities:
Cash dividends paid													(60,156)	(52,825)	(149,932)
Share repurchases													(1,752)	(7,847)	(5,273)
Redemption of junior subordinated debt													0	(8,119)	0
Excess tax benefit from stock-based compensation													1,425	332	945
Proceeds from options exercised													10,856	4,303	6,519
Net cash used in financing activities													(1,063,851)	(97,688)	(173,776)
Net increase/ (decrease) in cash and cash equivalents													222,459	(73,298)	(151,199)
Cash and cash equivalents at beginning of period				167,408				240,706				391,905	167,408	240,706	391,905
Cash and cash equivalents at end of period	389,867				167,408				240,706				389,867	167,408	240,706
Parent Company
Operating activities:
Net Income													49,667	60,540	61,962
Adjustments to reconcile net income to net cash provided by operating activities:
Undistributed earnings of subsidiary													(2,760)	70,854	3,261
Noncash stock benefit plan compensation expense													10,916	5,654	5,714
Gain on sale of marketable securities													(43)	(54)	(2,768)
Net change in other assets and liabilities													(63,533)	(5,824)	(2,352)
Net cash provided by operating activities													(5,753)	131,170	65,817
Investing activities:
Proceeds from sale of marketable securities available-for-sale													(1,952)	1,192	2,658
Acquisition, net of cash received													0	(89,398)	0
Net cash provided by/ (used in) investing activities													(1,952)	(88,206)	2,658
Financing activities:
Cash dividends paid													(60,156)	(52,825)	(149,932)
Share repurchases													(1,752)	(7,847)	(5,273)
Repayment of loan to ESOP													797	1,549	1,190
Redemption of junior subordinated debt													0	(8,119)	0
Excess tax benefit from stock-based compensation													1,425	332	945
Proceeds from options exercised													10,856	4,303	6,519
Net cash used in financing activities													(48,830)	(62,607)	(146,551)
Net increase/ (decrease) in cash and cash equivalents													(56,535)	(19,643)	(78,076)
Cash and cash equivalents at beginning of period				$ 91,056				$ 110,699				$ 188,775	91,056	110,699	188,775
Cash and cash equivalents at end of period	$ 34,521				$ 91,056				$ 110,699				$ 34,521	$ 91,056	$ 110,699

Business Segments (Details)

Business Segments (Details) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016USD ($)	Sep. 30, 2016USD ($)	Jun. 30, 2016USD ($)	Mar. 31, 2016USD ($)	Dec. 31, 2015USD ($)	Sep. 30, 2015USD ($)	Jun. 30, 2015USD ($)	Mar. 31, 2015USD ($)	Dec. 31, 2014USD ($)	Sep. 30, 2014USD ($)	Jun. 30, 2014USD ($)	Mar. 31, 2014USD ($)	Dec. 31, 2016USD ($)segment	Dec. 31, 2015USD ($)	Dec. 31, 2014USD ($)
Segment Reporting [Abstract]
Number of reportable business segments | segment													2
Business Segments
Interest income	$ 90,033	$ 84,748	$ 85,555	$ 85,298	$ 85,639	$ 81,091	$ 75,970	$ 76,880	$ 76,586	$ 76,528	$ 76,987	$ 75,326	$ 345,634	$ 319,580	$ 305,427
Interest expense	7,091	7,454	10,008	13,746	14,486	14,150	13,792	13,899	13,982	14,187	14,214	14,204	38,299	56,327	56,587
Provision for loan losses	2,145	5,538	4,199	1,660	4,595	3,167	1,050	900	1,078	3,466	8,285	7,485	13,542	9,712	20,314
Noninterest income	24,819	20,818	20,275	19,448	19,546	18,140	16,525	14,625	17,221	17,737	16,427	19,381	85,360	68,836	70,766
Noninterest expense	68,761	73,680	102,122	63,275	61,227	63,804	55,135	53,711	55,212	53,354	53,806	53,163	307,838	233,877	215,535
Income tax expense/ (benefit)	12,361	4,697	(3,491)	8,081	8,684	5,238	7,213	6,825	6,190	5,926	4,435	5,244	21,648	27,960	21,795
Net income	24,494	$ 14,197	$ (7,008)	$ 17,984	16,193	$ 12,872	$ 15,305	$ 16,170	17,345	$ 17,332	$ 12,674	$ 14,611	49,667	60,540	61,962
Total assets	9,623,640				8,951,899				7,775,033				9,623,640	8,951,899	7,775,033
Intersegment
Business Segments
Interest income													0	0	0
Community Banks
Business Segments
Interest income													327,855	300,746	285,635
Interest expense													33,883	51,895	52,291
Provision for loan losses													9,846	7,429	17,500
Noninterest income													83,631	67,167	66,431
Noninterest expense													295,023	219,793	202,489
Income tax expense/ (benefit)													23,023	28,642	21,097
Net income													52,275	62,547	61,095
Total assets	9,500,419				8,827,574				7,650,665				9,500,419	8,827,574	7,650,665
Community Banks | Intersegment
Business Segments
Interest income													2,564	2,393	2,406
Consumer Finance
Business Segments
Interest income													17,064	17,978	18,789
Interest expense													2,564	2,393	2,406
Provision for loan losses													3,696	2,283	2,814
Noninterest income													1,597	1,555	1,517
Noninterest expense													11,579	12,120	11,968
Income tax expense/ (benefit)													336	1,138	1,291
Net income													486	1,599	1,827
Total assets	109,744				110,670				107,216				109,744	110,670	107,216
Consumer Finance | Intersegment
Business Segments
Interest income													0	0	0
All Other
Business Segments
Interest income													715	856	1,003
Interest expense													1,852	2,039	1,890
Provision for loan losses													0	0	0
Noninterest income													132	114	2,818
Noninterest expense													1,236	1,964	1,078
Income tax expense/ (benefit)													(1,711)	(1,820)	(593)
Net income													(3,094)	(3,606)	(960)
Total assets	$ 13,477				$ 13,655				$ 17,152				13,477	13,655	17,152
All Other | Intersegment
Business Segments
Interest income													$ (2,564)	$ (2,393)	$ (2,406)

Guaranteed Preferred Benefic114

Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements - Narrative (Details)	Dec. 15, 2005USD ($)$ / sharesshares	Dec. 05, 2005USD ($)$ / sharesshares	Dec. 31, 2016USD ($)trustderivative	Dec. 31, 2015USD ($)trust$ / sharesshares
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Number of statutory business trusts owned | trust			2
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities			$ 111,213,000	$ 111,213,000
Hedge ineffectiveness for swaps			$ 0
Interest rate swaps
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Number of agreements | derivative			2
Collateral posted			$ 3,005,000	4,705,000
Fair value, liability			$ 2,736,000	4,276,000
Northwest Bancorp Capital Trust III | Interest rate swaps
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Original term of swaps			10 years
Fixed rate (as a percent)			4.61%
Northwest Bancorp Capital Trust III | Interest rate swaps | Cash flow hedges
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Notional amount			$ 25,000,000
Northwest Bancorp Statutory Trust IV | Interest rate swaps
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Original term of swaps			10 years
Trust preferred investments
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Total value of cumulative trust preferred securities issued			$ 107,875,000
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities			$ 111,213,000	111,213,000
Maximum period for which interest payment on the subordinated debentures can be deferred			5 years
Interest deferral			$ 0
Trust preferred investments | Northwest Bancorp Capital Trust III
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Cumulative trust preferred securities issued (in shares) | shares		50,000
Cumulative trust preferred securities issued, liquidation value per preferred security (in dollars per security) | $ / shares		$ 1,000
Total value of cumulative trust preferred securities issued		$ 50,000,000	$ 50,000,000
Variable rate basis		three-month LIBOR
Spread on variable rate basis (as a percent)		1.38%	1.38%
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities			$ 51,547,000	51,547,000
Effective interest rate (as a percent)			2.38%
Trust preferred investments | Northwest Bancorp Statutory Trust IV
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Cumulative trust preferred securities issued (in shares) | shares	50,000
Cumulative trust preferred securities issued, liquidation value per preferred security (in dollars per security) | $ / shares	$ 1,000
Total value of cumulative trust preferred securities issued	$ 50,000,000		$ 50,000,000
Variable rate basis			three-month LIBOR
Spread on variable rate basis (as a percent)	1.38%		1.38%
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities			$ 51,547,000	51,547,000
Effective interest rate (as a percent)			2.34%
Trust preferred investments | Northwest Bancorp Statutory Trust IV | Swap 4
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Fixed rate (as a percent)			4.09%
Trust preferred investments | Northwest Bancorp Statutory Trust IV | Swap 4 | Cash flow hedges
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Notional amount			$ 25,000,000
Trust preferred investments | LNB Trust I and LNB Trust II
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Fixed interest rate of securities			6.64%
Trust preferred investments | LNB Trust II
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Total value of cumulative trust preferred securities issued			$ 7,875,000
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities			$ 8,119,000	$ 8,119,000
LNB
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Number of statutory business trusts owned | trust				2
Cumulative Preferred Stock | Trust preferred investments | LNB Trust I and LNB Trust II
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Securities outstanding (in shares) | shares				7,875
Liquidation value per preferred security (in dollars per security) | $ / shares				$ 1,000
Securities outstanding, liquidation value				$ 7,875,000
LIBOR | Trust preferred investments | LNB Trust I and LNB Trust II
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Spread on variable rate basis (as a percent)			1.48%

Guaranteed Preferred Benefic115

Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements - Liability Derivatives (Details) - Interest rate swaps - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Liability Derivatives, Included in Other Liabilities
Fair value	$ 2,736	$ 4,276
Notional amount	50,000	50,000
Collateral posted	$ 3,005	$ 4,705

Guaranteed Preferred Benefic116

Guaranteed Preferred Beneficial Interests in Company’s Junior Subordinated Deferrable Interest Debentures (Trust-Preferred Securities) and Interest Rate Swap Agreements (Details) - USD ($)	Dec. 31, 2016	Dec. 31, 2015	Dec. 15, 2005	Dec. 05, 2005
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	$ 111,213,000	$ 111,213,000
Trust preferred investments
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Total value of cumulative trust preferred securities issued	107,875,000
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	111,213,000	111,213,000
Trust preferred investments | Northwest Bancorp Capital Trust III
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Total value of cumulative trust preferred securities issued	50,000,000			$ 50,000,000
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	51,547,000	51,547,000
Trust preferred investments | Northwest Bancorp Statutory Trust IV
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Total value of cumulative trust preferred securities issued	50,000,000		$ 50,000,000
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	51,547,000	51,547,000
Trust preferred investments | LNB Trust II
Guaranteed Preferred Beneficial Interests in the Company's Junior Subordinated Deferrable Interest Debentures (Trust Preferred Securities) and Interest Rate Swaps
Total value of cumulative trust preferred securities issued	7,875,000
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	$ 8,119,000	$ 8,119,000

Selected Quarterly Financial117

Selected Quarterly Financial Data - Unaudited (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Interest income	$ 90,033	$ 84,748	$ 85,555	$ 85,298	$ 85,639	$ 81,091	$ 75,970	$ 76,880	$ 76,586	$ 76,528	$ 76,987	$ 75,326	$ 345,634	$ 319,580	$ 305,427
Interest expense	7,091	7,454	10,008	13,746	14,486	14,150	13,792	13,899	13,982	14,187	14,214	14,204	38,299	56,327	56,587
Net interest income	82,942	77,294	75,547	71,552	71,153	66,941	62,178	62,981	62,604	62,341	62,773	61,122	307,335	263,253	248,840
Provision for loan losses	2,145	5,538	4,199	1,660	4,595	3,167	1,050	900	1,078	3,466	8,285	7,485	13,542	9,712	20,314
Noninterest income	24,819	20,818	20,275	19,448	19,546	18,140	16,525	14,625	17,221	17,737	16,427	19,381	85,360	68,836	70,766
Noninterest expenses	68,761	73,680	102,122	63,275	61,227	63,804	55,135	53,711	55,212	53,354	53,806	53,163	307,838	233,877	215,535
Income before income taxes	36,855	18,894	(10,499)	26,065	24,877	18,110	22,518	22,995	23,535	23,258	17,109	19,855	71,315	88,500	83,757
Income tax expense/ (benefit)	12,361	4,697	(3,491)	8,081	8,684	5,238	7,213	6,825	6,190	5,926	4,435	5,244	21,648	27,960	21,795
Net income	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 16,193	$ 12,872	$ 15,305	$ 16,170	$ 17,345	$ 17,332	$ 12,674	$ 14,611	$ 49,667	$ 60,540	$ 61,962
Basic earnings per share (in dollars per share)	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 0.16	$ 0.14	$ 0.17	$ 0.18	$ 0.19	$ 0.19	$ 0.14	$ 0.16	$ 0.50	$ 0.64	$ 0.68
Diluted earnings per share (in dollars per share)	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 0.16	$ 0.13	$ 0.17	$ 0.18	$ 0.19	$ 0.19	$ 0.14	$ 0.16	$ 0.49	$ 0.64	$ 0.67
Compensation and employee benefits													$ (140,927)	$ (119,818)	$ (115,967)
Reclassification of Amortization of Broker Fees
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net interest income		$ (1,400)	$ (1,100)
Compensation and employee benefits		$ 1,400	$ 1,100

Subsequent Events - Unaudited (

Subsequent Events - Unaudited (Details) $ in Thousands	3 Months Ended
	Jun. 30, 2017USD ($)branch	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total deposits included in divestiture		$ 215,649
Total performing included in divestiture		146,660
Assets held-for-sale:
Performing Loans		146,660
Accrued interest receivable		416
Premises and equipment, net		5,452
Total assets held-for-sale		152,528	$ 0
Liabilities held-for-sale:
Noninterest-bearing demand deposits		34,657
Interest-bearing demand deposits		17,181
Money market deposit accounts		45,806
Savings deposits		55,205
Time deposits		62,800
Total deposits		215,649
Accrued interest payable		8
Total liabilities held-for-sale		215,657	$ 0
Residential mortgage loans
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total performing included in divestiture		26,406
Assets held-for-sale:
Performing Loans		26,406
Home equity loans
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total performing included in divestiture		15,725
Assets held-for-sale:
Performing Loans		15,725
Consumer loans
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total performing included in divestiture		522
Assets held-for-sale:
Performing Loans		522
Commercial real estate loans
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total performing included in divestiture		101,123
Assets held-for-sale:
Performing Loans		101,123
Commercial loans
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Total performing included in divestiture		2,884
Assets held-for-sale:
Performing Loans		$ 2,884
Scenario, Forecast
Disposal Group, Including Discontinued Operation, Balance Sheet Disclosures [Abstract]
Number of branch locations to be sold | branch	3
Total deposits included in divestiture	$ 216,000
Total performing included in divestiture	147,000
Total cash included in divestiture	$ 40,000
Consideration receivable, deposit premium	8.00%
Anticipated gain on disposal	$ 17,000
Assets held-for-sale:
Performing Loans	147,000
Liabilities held-for-sale:
Total deposits	$ 216,000