Northwest Bancshares (NWBI) 10-K 1 Mar 19 2018 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Feb. 22, 2019	Jun. 30, 2018
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
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Type	10-K
Document Period End Date	Dec. 31, 2018
Document Fiscal Year Focus	2,018
Document Fiscal Period Focus	FY
Amendment Flag	false
Entity Common Stock, Shares Outstanding		103,689,288
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float			$ 1,793

CONSOLIDATED STATEMENTS OF FINA

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets
Cash and cash equivalents	$ 68,789	$ 77,710
Marketable securities available-for-sale (amortized cost of $811,015 and $800,094)	801,450	792,535
Marketable securities held-to-maturity (fair value of $22,446 and $29,667)	22,765	29,678
Loans receivable, net of allowance for loan losses of $55,214 and $56,795	7,996,225	7,736,614
Accrued interest receivable	24,490	23,352
Real estate owned, net	2,498	5,666
Federal Home Loan Bank stock, at cost	15,635	11,733
Premises and equipment, net	143,390	151,944
Bank owned life insurance	171,079	171,547
Goodwill	307,420	307,420
Other intangible assets	19,821	25,669
Other assets	34,211	30,066
Total assets	9,607,773	9,363,934
Liabilities:
Deposits	7,894,179	7,826,989
Borrowed funds	234,389	108,238
Advances by borrowers for taxes and insurance	43,298	40,825
Accrued interest payable	744	460
Other liabilities	66,312	68,485
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities	111,213	111,213
Total liabilities	8,350,135	8,156,210
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, 103,354,030, and 102,394,828 shares issued, respectively	1,034	1,027
Paid-in capital	745,926	730,719
Retained earnings	550,374	508,058
Accumulated other comprehensive loss	(39,696)	(32,080)
Total shareholders’ equity	1,257,638	1,207,724
Total liabilities and shareholders’ equity	$ 9,607,773	$ 9,363,934

CONSOLIDATED STATEMENTS OF FI_2

CONSOLIDATED STATEMENTS OF FINANCIAL CONDITION (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Marketable securities available-for-sale, amortized cost	$ 811,015	$ 800,094
Marketable securities held-to-maturity, fair value	22,446	29,667
Allowance for loan losses	$ 55,214	$ 56,795
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	50,000,000	50,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	500,000,000	500,000,000
Common stock, shares issued (in shares)	103,354,030	102,394,828

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Interest income:
Loans receivable	$ 356,571	$ 339,992	$ 329,039
Mortgage-backed securities	13,781	11,343	8,540
Taxable investment securities	3,064	3,749	3,409
Tax-free investment securities	1,078	2,023	2,732
FHLB dividends	452	250	1,371
Interest-earning deposits	835	1,499	543
Total interest income	375,781	358,856	345,634
Interest expense:
Deposits	30,985	23,057	23,465
Borrowed funds	6,155	5,014	14,834
Total interest expense	37,140	28,071	38,299
Net interest income	338,641	330,785	307,335
Provision for loan losses	20,332	19,751	13,542
Net interest income after provision for loan losses	318,309	311,034	293,793
Noninterest income:
Gain on sale of investments, net	157	1,148	625
Service charges and fees	50,792	49,717	44,113
Trust and other financial services income	16,581	17,987	14,103
Insurance commission income	8,791	9,013	10,522
Loss on real estate owned, net	(631)	(797)	(39)
Income from bank owned life insurance	5,821	6,093	5,361
Mortgage banking income	596	1,418	4,894
Gain on sale of offices	0	17,186	0
Other operating income	9,595	8,715	5,781
Total noninterest income	91,702	110,480	85,360
Noninterest expense:
Compensation and employee benefits	152,395	152,296	142,595
Premises and occupancy costs	27,519	28,863	26,134
Office operations	14,139	16,342	14,898
Collections expense	2,209	2,849	2,431
Processing expenses	39,046	39,086	34,859
Marketing expenses	8,434	9,607	8,852
Federal deposit insurance premiums	2,746	3,518	4,404
Professional services	10,598	10,293	7,865
Amortization of intangible assets	5,848	6,764	4,259
Real estate owned expense	817	1,004	1,004
Restructuring/acquisition expense	1,014	4,419	12,213
FHLB prepayment penalty	0	0	36,978
Other expense	11,333	10,562	11,346
Total noninterest expense	276,098	285,603	307,838
Income before income taxes	133,913	135,911	71,315
Provision for income taxes:
Federal	21,948	34,801	20,313
State	6,474	6,643	1,335
Total provision for income taxes	28,422	41,444	21,648
Net income	$ 105,491	$ 94,467	$ 49,667
Basic earnings per share (in dollars per share)	$ 1.03	$ 0.94	$ 0.50
Diluted earnings per share (in dollars per share)	$ 1.02	$ 0.92	$ 0.49

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Net Income	$ 105,491	$ 94,467	$ 49,667
Net unrealized holding losses on marketable securities:
Unrealized holding losses, net of tax of $513, $1,915 and $1,742, respectively	(1,277)	(2,478)	(2,728)
Reclassification adjustment for gains included in net income, net of tax of $60, $1,488 and $129, respectively	(155)	(2,326)	(202)
Net unrealized holding losses on marketable securities	(1,432)	(4,804)	(2,930)
Change in fair value of interest rate swaps, net of tax of $(223), $(585) and $(539), respectively	840	1,087	1,001
Defined benefit plans:
Net loss, net of tax of $770, $826 and $3,061, respectively	(1,181)	(1,254)	(2,399)
Amortization of prior service costs, net of tax of $(746), $(613) and $(606), respectively	903	882	872
Net loss on defined benefit plans	(278)	(372)	(1,527)
Other comprehensive loss	(870)	(4,089)	(3,456)
Total comprehensive income	$ 104,621	$ 90,378	$ 46,211

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Comprehensive Income [Abstract]
Income tax (expense) benefit related to unrealized holding gains/ losses on securities	$ 513	$ 1,915	$ 1,742
Income tax (expense) benefit related to (gain) loss on securities	60	1,488	129
Income tax (expense) benefit related to derivatives qualifying as hedges	(223)	(585)	(539)
Income tax on defined benefit plan gain (loss)	770	826	3,061
Income tax expense (benefit) related to compensation and employee benefits	$ (746)	$ (613)	$ (606)

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, 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	(3,456)				(3,456)
Total comprehensive income	46,211			49,667	(3,456)
Shares issued to acquire LNB Bancorp, Inc.	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	12,341	3	6,032			6,306
Dividends paid	(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
Comprehensive income:
Net Income	94,467			94,467
Other comprehensive loss net of tax	(4,089)				(4,089)
Total comprehensive income	90,378			94,467	(4,089)
ESOP termination	0	0	0			0
Exercise of stock options	7,001	6	6,995
Share repurchases	0	0	0
Stock-based compensation expense including tax benefits	4,894	4	4,890	0		0
Dividends paid	(65,212)			(65,212)
Balance at end of the period at Dec. 31, 2017	1,207,724	1,027	730,719	508,058	(32,080)	0
Increase (Decrease) in Stockholders' Equity
Reclassification due to adoption of ASU No. 2018-02	(6,746)			6,746	(6,746)
Comprehensive income:
Net Income	105,491			105,491
Other comprehensive loss net of tax	(870)				(870)
Total comprehensive income	104,621			112,237	(7,616)
Exercise of stock options	8,191	8	8,183
Stock-based compensation expense including tax benefits	7,023	4	7,019			0
Stock-based compensation forfeited	0	(5)	5
Dividends paid	(69,921)			(69,921)
Balance at end of the period at Dec. 31, 2018	$ 1,257,638	$ 1,034	$ 745,926	$ 550,374	$ (39,696)	$ 0

CONSOLIDATED STATEMENTS OF CH_2

CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Stockholders' Equity [Abstract]
Other comprehensive income, tax	$ 374	$ 3,031	$ 3,787
Stock-based compensation expense, tax benefits			$ 1,425
Dividends paid, per share (in dollars per share)	$ 0.68	$ 0.64	$ 0.60

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net Income	$ 105,491	$ 94,467	$ 49,667
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan losses	20,332	19,751	13,542
Net gain on sale of assets	1,677	(627)	(4,499)
Net gain on sale of offices	0	(17,186)	0
Net depreciation, amortization and accretion	8,120	14,293	15,424
(Increase)/decrease in other assets	(6,428)	2,902	24,763
Increase/(decrease) in other liabilities	(1,129)	11,694	4,801
Net amortization of premium on marketable securities	1,871	2,017	2,139
Noncash compensation expense related to stock benefit plans	7,023	4,894	10,916
Noncash impairment of real estate owned	1,518	1,231	1,481
Deferred income tax (benefit)/expense	(2,770)	11,317	2,734
FHLB prepayment penalty	0	0	24,520
Origination of loans held for sale	(1,297)	(66,058)	(252,204)
Proceeds from sale of loans held for sale	4,501	73,103	242,428
Net cash provided by operating activities	138,909	151,798	135,712
Investing activities:
Purchase of marketable securities held-to-maturity	0	(23,621)	0
Purchase of marketable securities available-for-sale	(228,180)	(218,292)	(238,673)
Proceeds from maturities and principal reductions of marketable securities held-to-maturity	6,892	13,902	11,700
Proceeds from maturities and principal reductions of marketable securities available-for-sale	210,362	206,089	278,621
Proceeds from sale of marketable securities available-for-sale	5,206	36,811	1,951
Proceeds of bank-owned life insurance	2,730	4,259	1,190
Net increase in loans	(276,707)	(120,076)	(33,434)
Net (purchases)/redemptions of Federal Home Loan Bank stock	(3,902)	(4,343)
Net (purchases)/redemptions of Federal Home Loan Bank stock			33,513
Proceeds from sale of real estate owned	6,312	4,342	8,113
Sale of real estate owned for investment	607	608	607
Purchases of premises and equipment	(5,233)	(3,719)	(15,227)
Acquisitions, net of cash received	0	0	1,102,237
Net cash provided by/(used in) investing activities	(281,913)	(104,040)	1,150,598
Financing activities:
Net increase/(decrease) in deposits	67,190	(270,989)	(157,457)
Repayments of long-term borrowings	0	0	(774,863)
Net increase/(decrease) in short-term borrowings	126,151
Net increase/(decrease) in short-term borrowings		(34,661)	(81,765)
Increase/(decrease) in advances by borrowers for taxes and insurance	2,473	3,946	(139)
Share repurchases	0	0	(1,752)
Cash dividends paid on common stock	(69,921)	(65,212)	(60,156)
Proceeds from stock options exercised	8,190	7,001	10,856
Excess tax benefit from stock-based compensation	0	0	1,425
Net cash provided by/(used) in financing activities	134,083	(359,915)	(1,063,851)
Cash and cash equivalents at beginning of period	77,710	389,867	167,408
Net increase/(decrease) in cash and cash equivalents	(8,921)	(312,157)	222,459
Cash and cash equivalents at end of period	68,789	77,710	389,867
Cash paid during the period for:
Interest on deposits and borrowings (including interest credited to deposit accounts of $29,330, $22,385 and $22,213, respectively)	36,856	28,254	39,649
Income taxes	25,849	32,270	9,710
Business acquisitions
Fair value of assets acquired	0	0	546,247
Net cash received	0	0	1,102,237
Liabilities assumed	0	0	1,648,484
Loan foreclosures and repossessions	7,181	8,130	6,252
Sale of real estate owned financed by the Company	$ 296	$ 168	$ 498

CONSOLIDATED STATEMENTS OF CA_2

CONSOLIDATED STATEMENTS OF CASH FLOWS (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Statement of Cash Flows [Abstract]
Interest on deposits and borrowings, interest credited to deposit accounts	$ 29,330	$ 22,385	$ 22,213

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2018
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 172 banking locations in Pennsylvania, New York, and Ohio. (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 statements of financial condition and 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 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 during the years ended December 31, 2018 and 2017 . 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. (e) Loans Receivable Our loan segments consist of Personal Banking and Business Banking loans. Personal Banking loans include residential mortgage, home equity and consumer loans. Business Banking loans include commercial real estate and commercial loans. 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 income when it has been determined that all principal and interest will be collected or are applied to principal when collectability of contractual 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 borrower is experiencing financial difficulties and the restructuring constitutes a concession. 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, 2018 and 2017 , there were $0 and $3.1 million of residential mortgage loans classified as held for sale, respectively. Acquired loans are initially measured 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 incurred losses, adjusted for a loss emergence 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) Restricted Investment in Federal Home Loan Bank Stock 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. FHLB stock is carried at cost and evaluated or impairment based on the ultimate recoverability of the par value. FHLB stock can only be purchased, redeemed and transferred at par value. Dividends are reported in interest income in the Consolidated Statements of Income. (i) 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. (j) Goodwill Goodwill is generated from the premium paid for an acquisition and is allocated to reporting units, which are either our reportable segments or one level below. 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. 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. In testing goodwill for impairment, we have the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If, after assessing all events and circumstances, we determine it is not more likely than not that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test would be unnecessary. However, if we conclude otherwise, it would then be required to perform the first step of the goodwill impairment test, and continue to the second step, if necessary. Step 1 requires the fair value of each reporting unit be compared to its carrying amount, including goodwill. 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. We conducted our annual impairment assessment as of June 30, 2018 by first performing a qualitative assessment of goodwill to determine if it was more likely than not that the fair value was less than the carrying value. In performing a qualitative analysis, factors considered include, but are not limited to, macroeconomic conditions, industry and market conditions and overall financial performance. The results of the qualitative assessment for 2018 indicated that it was not more likely than not that the fair value of the reporting unit was less than the carrying value. Consequently, no additional quantitative two-step impairment test was required and no impairment was recorded in 2018. As of June 30, 2017, we performed a quantitative impairment test that did not result in any impairment. Future events could cause us to conclude that goodwill has become impaired, which would result in recording an impairment loss. There were no changes in our operations that would cause us to update the assessment performed as of June 30, 2018 and 2017. Accordingly, we have determined that goodwill is not impaired as of December 31, 2018 and 2017. (k) Core Deposit 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 seven to eleven years. (l) Bank-Owned Life Insurance We own insurance on the lives of a certain group of current and former 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 covered by these policies, after distribution to the insured’s beneficiaries, if any, we receive a tax-free death benefit, which is recorded as noninterest income. (m) Deposits Interest on deposits is accrued and charged to expense monthly and is paid or credited in accordance with the terms of the accounts. (n) 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. (o) 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. The effect on deferred tax assets and liabilities with regard to a change in tax rates is recognized in the tax provision in the period the change is enacted. (p) 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. For options outstanding at December 31, 2018 , the following assumptions were used to determine the options fair value: (1) annual rate of quarterly dividends ranging from 3.2% to 5.1% based on historical dividends and market prices; (2) expected volatility of 14.0% to 22.0% based on historical average monthly 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. During the year ended December 31, 2018 , we awarded 831,160 stock options to employees and 64,800 stock options to directors. The options granted in 2018 vest over a seven -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, 2017 , we awarded 754,210 stock options to employees and 64,800 stock options to directors.The options granted in 2017 vest over a ten -year period, with the first vesting occurring on the grant date. New shares are issued when options are exercised. 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. 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. During the year ended December 31, 2018 , we awarded 390,030 restricted shares to employees and 24,300 restricted shares to directors. The common share awards granted in 2018 vest over a seven -year period, with the first vesting occurring on the grant date. During the year ended December 31, 2017 , we awarded 353,750 common shares to employees and 24,300 common shares to directors. The common share awards granted in 2017 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, see note 14. Stock-based employee compensation expense related to common share awards of $5.8 million , $3.8 million and $3.5 million was included in income before income taxes during the years ended December 31, 2018 , 2017 and 2016 , respectively. The effect on net income for the years ended December 31, 2018 , 2017 and 2016 was a reduction of $4.2 million , $2.3 million and $2.2 million , respectively. Total compensation expense for unvested stock options of $4.1 million has yet to be recognized as of December 31, 2018 . The weighted average period over which this remaining stock option expense will be recognized is approximately 3.97 years. (q) Segment Reporting As a result of the closure of the Northwest Consumer Discount Company in the third quarter 2017, we have determined that we have one reportable segment beginning in the fourth quarter 2017. The Company provides services traditionally offered by full-service community banks, including business and personal deposit accounts and business and personal loans, as well as insurance, brokerage and investment management and trust services. The Company’s non-banking activities are immaterial and, therefore, separate information has not been disclosed. (r) Derivative financial instruments 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. At times, 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 which is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The ineffective portion of the unrealized gain or loss, if any, would be recorded in other expense. For derivatives that are not designated as hedging instruments, any gain or loss is recognized immediately in earnings. (s) 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. (t) 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, pension 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. (u) 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, 2018
Accounting Changes and Error Corrections [Abstract]
Recent Accounting Pronouncements	Recent Accounting Pronouncements (a) Recently Adopted Accounting Standards In May 2014 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606)”. Effective January 1, 2018, we adopted the ASU and all related amendments to all contracts using the modified retrospective approach, with the cumulative effect recorded as an adjustment to opening retained earnings. Due to immateriality, we had no cumulative effect to record. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. We expect the impact of the adoption of the new standard to be immaterial to our net income on an ongoing basis. Our revenue is comprised of net interest income on financial assets and financial liabilities, which is explicitly excluded from the scope of ASU 2014-09, and non-interest income. The services that fall within the scope of ASC 606 include service charges and fees, trust and other financial services income, insurance commission income, sale of OREO and other operating income. Revenue is recognized when performance obligations under the terms of a contract with our customers are satisfied. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services. The majority of our revenue continues to be recognized at the point in time when the services are provided to our customers. Service charges and fees represents income earned on both loan and deposit accounts as well as interchange income. Service charges on deposit accounts primarily consist of overdraft, non-sufficient funds, ATM transaction fees and account management fees. Revenue is recognized at the point in time the transaction occurs or the service is provided to the customer. We earn interchange income from debit and credit cardholder transactions processed through payment networks. Interchange fees represent a percentage of the underlying transaction value and are generally set by the credit card associations. Interchange fees are recognized as transactions occur. We provide trust management services and investment management services to our customers and recognize revenue as these management services are provided. Trust and investment management services are billed and paid on a monthly or quarterly basis. Additionally, we earn commissions on investment products that are sold to our customers. These commissions are recognized at the time of the sale of the third party’s product or services to our customers. Our insurance subsidiary is an employee benefits and property and casualty insurance agency specializing in commercial and personal insurance as well as retirement benefit plans. Insurance commission income is recognized at the time of sale of the third party’s product or service to our customers. Loss on real estate owned represents gains and losses on real estate acquired by Northwest through the foreclosure process. Proceeds from the sale of these properties are recognized when control of the property transfers to the buyer. In certain instances the Bank may finance a portion of the purchase price paid by the buyer and an additional evaluation of whether all of the contract criteria are met is required. If it is not probable that we will collect substantially all of the consideration expected, the transaction would not be accounted for as a sale until the concerns about collectability are resolved. Other operating income consists primarily of revenues earned for providing transaction services to our deposit customers. The revenue is earned at the point in time the transaction occurs. We have evaluated the nature of our contracts with customers and determined that further disaggregation of revenue from contracts with customers into more granular categories beyond what is presented in the Consolidated Statements of Income was not necessary. 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. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We adopted this guidance as of January 1, 2018 which did not have a material impact on our results of operations and financial position. 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. Accordingly, we refined the calculation used to determine the disclosed fair value of our loans held for investment portfolio as part of adopting this standard. The refined calculation did not have a significant impact on our fair value disclosures. Refer to note 9, "Disclosures About Fair Value of Financial Instruments". In August 2016, the FASB issued ASU No. 2016-15, “ Classification of Certain Cash Receipts and Cash Payments ”. The main objective of this ASU is to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The amendments in this Update provide guidance on the following eight specific cash flow issues: debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of bank-owned life insurance (BOLI) policies, distributions received from equity method investments, beneficial interests in securitization transactions, and separately identifiable cash flows and application of the predominance principle. This guidance is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. We adopted this guidance as of January 1, 2018 and applied it on a retrospective basis. No material reclassifications were made for the year ended December 31, 2017. In January 2017, the FASB issued ASU No. 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business”. This guidance provides a more robust framework to use in determining when a set of assets and activities (“set”) is a business and to address stakeholder feedback that the definition of a business in current GAAP is applied too broadly. The primary amendments in the ASU provide a screen to exclude transactions where substantially all of the fair value of the transferred set is concentrated in a single asset, or group of similar assets, from being evaluated as a business. We adopted this standard on January 1, 2018 and will apply the guidance to future transactions. In January 2017, the FASB issued ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment" . This guidance eliminates the requirement to determine the fair value of individual assets and liabilities of a reporting unit to measure goodwill impairment. Under this guidance goodwill impairment testing will be performed by comparing the fair value of the reporting unit with its carrying amount and recognizing an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value. This guidance is effective for annual and interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis. Early adoption is permitted for annual and interim goodwill impairment testing dates after January 1, 2017.We have elected to early adopt this standard as of January 1, 2018 and the amendments were applied on a prospective basis. The adoption did not have a material impact on the consolidated financial statements. In March 2017, the FASB issued ASU 2017-08, "Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities". This guidance shortens the amortization period for certain callable debt securities held at a premium to the earliest call date from the maturity date. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted in any interim period. We have elected to early adopt this standard as of January 1, 2018. The adoption did not have a material impact on our results of operations or financial position. In May 2017, the FASB issued ASU 2017-09, “Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting”. This guidance clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as a modification. Under ASU 2017-09, an entity will not apply modification accounting to a share-based payment award if all of the following are the same immediately before and after the change: (i) the award's fair value, (ii) the award's vesting conditions and (iii) the award's classification as an equity or liability instrument. This guidance is effective for annual and interim periods beginning after December 15, 2017 and should be applied on a prospective basis to an award modified on or after the adoption date. We adopted this standard as of January 1, 2018 and will apply the guidance to future modifications. In March 2017, the FASB issued ASU No. 2017-07, “Compensation Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Costs and Net Periodic Postretirement Benefit Costs ". This guidance provides financial statement users with clearer and disaggregated information related to the components of net periodic benefit cost and improve transparency of the presentation of net periodic benefit cost in the financial statements. Employers will present the service cost component of net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. Employers will present the other components of the net periodic benefit cost separately from the line items that includes the service cost outside of any subtotal of operating income, if one is presented. This guidance is effective for annual and interim periods beginning after December 15, 2017 and should be applied retrospectively. We adopted this standard as of January 1, 2018. The other components of the net periodic benefit cost for the year ended December 31, 2017 and December 31, 2016 totaled $2.1 million and $1.6 million , respectively, and were reclassified from compensation and employee benefits to other expense. In February 2018, the FASB issued ASU 2018-02, " Income Statement - Reporting Comprehensive Income (Topic 220)-Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." This guidance permits a reclassification from accumulated other comprehensive income to retained earnings of the stranded tax effects resulting from the Tax Cuts and Jobs Act. This guidance is effective for annual or interim reporting periods beginning after December 15, 2018, but permits early adoption in a period for which financial statements have not been issued. We have elected to early adopt the ASU as of January 1, 2018. The reclassification from accumulated other comprehensive income to retained earnings was $6.7 million for the release of stranded income tax benefits relating to the unrealized net gains and losses on available for sale securities and the change in fair value of our interest rate swaps and our pension plan. Our policy for releasing income tax effects from accumulated other comprehensive income is to release them when investments are sold or matured and liabilities are extinguished. (b) Recently Issued Accounting Standards 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 will utilized the transition method included in ASU 2018-11 which will allow us to apply ASU 2016-02 at the adoption date, as opposed to at the beginning of the earliest period presented. Our reporting for periods prior to January 1, 2019 will continue to be in accordance with Leases (Topic 840). We have elected to apply the package of practical expedients, which, among other things, allows for the carry forward of the historical lease classification for leases that commenced before the effective date, and the ability to use hindsight in evaluating lessee options to extend or terminate a lease. We lease certain branch and office facilities or land under operating leases. Based on our evaluation, the right-of-use asset and corresponding lease obligation liability is expected to be approximately $40 million to $45 million . The Company does not believe the new lease standard will materially affect its consolidated net income. 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 and instead requires 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 assets 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 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. Management created a formal working group to govern the implementation of these amendments consisting of key stakeholders from finance, risk, credit and accounting. We are currently in the process of designing current expected credit loss estimation methodologies and systems, and collecting data to be able to comply with the standard. We have engaged with a third-party to assist in the development of certain portfolio-level estimation methodologies and have chosen a third-party software platform provider. We are also evaluating the effect this guidance will have on our results of operations, financial position and related disclosures. The impact of the ASU will depend upon the state of the economy and the nature of our portfolios, among other items, at the date of adoption. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820) - Disclosure Framework Changes to the Disclosure Requirements for Fair Value Measurement.” This guidance removes, modifies and adds disclosure requirements for fair value measurements. This guidance is effective for annual periods beginning after December 15, 2019, including interim periods within those years, with early adoption permitted for any removed or modified disclosure requirements. Transition is on a prospective basis for the new and modified disclosures, and on a retrospective basis for disclosures that have been eliminated. We do not expect this guidance to have a material impact on our financial statements. In August 2018, the FASB issued ASU 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans General (Subtopic 715-20) - Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans.” This guidance removes and adds disclosure requirements for defined benefit pension or other post-retirement plans. This guidance is effective for annual periods beginning after December 15, 2020, with early adoption permitted, and requires retrospective adoption for all periods presented. We do not expect this guidance to have a material impact on our financial statements. In August 2018, the FASB issued ASU 2018-15, “Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40)-Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract.” This guidance aligns the requirements for capitalization of implementation costs incurred in a hosting arrangement that is a service contract with the existing guidance for internal-use software. This guidance is effective for annual periods beginning after December 15, 2019, including interim periods within those years, with early adoption permitted. Transition can either be on a retrospective basis or a prospective basis on all implementation costs incurred after the date of adoption. We are evaluating the impact this new accounting guidance will have on our financial statements.

Marketable Securities

Marketable Securities	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Marketable Securities	Marketable Securities Marketable securities available-for-sale at December 31, 2018 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 through five years $ 14,756 24 — 14,780 Debt issued by government sponsored enterprises: 3 Due in one year or less 85,089 — (795 ) 84,294 Due in one year through five years 101,078 71 (1,512 ) 99,637 Due after ten years 3,546 — (142 ) 3,404 Municipal securities: Due in one year or less 1,333 2 (6 ) 1,329 Due in one year through five years 3,985 54 (4 ) 4,035 Due in five years through ten years 10,603 60 — 10,663 Due after ten years 5,105 31 — 5,136 Corporate debt issues: Due in five years through ten years 914 — — 914 Residential mortgage-backed securities: Fixed rate pass-through 130,172 568 (4,113 ) 126,627 Variable rate pass-through 24,761 1,003 (5 ) 25,759 Fixed rate agency CMOs 365,427 865 (5,921 ) 360,371 Variable rate agency CMOs 64,246 280 (25 ) 64,501 Total residential mortgage-backed securities 584,606 2,716 (10,064 ) 577,258 Total marketable securities available-for-sale $ 811,015 2,958 (12,523 ) 801,450 Marketable securities held to maturity at December 31, 2018 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Residential mortgage-backed securities: Fixed rate pass-through $ 2,896 53 — 2,949 Variable rate pass-through 1,666 39 — 1,705 Fixed rate agency CMOs 17,552 — (422 ) 17,130 Variable rate agency CMOs 651 11 — 662 Total residential mortgage-backed securities 22,765 103 (422 ) 22,446 Total marketable securities held-to-maturity $ 22,765 103 (422 ) 22,446 Marketable securities available-for-sale at December 31, 2017 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 $ 1 — — 1 Debt issued by government sponsored enterprises: Due in one year or less 66,566 14 (289 ) 66,291 Due after one year through five years 140,624 — (2,402 ) 138,222 Due after five years through ten years — — — — Due after ten years 4,833 — (77 ) 4,756 Equity securities 551 29 (6 ) 574 Municipal securities: Due in one year or less 2,492 7 (1 ) 2,498 Due after one year through five years 7,072 82 (6 ) 7,148 Due after five years through ten years 14,576 171 — 14,747 Due after ten years 26,371 292 — 26,663 Corporate debt issues: Due after ten years 909 — — 909 Residential mortgage-backed securities: Fixed rate pass-through 144,411 1,108 (2,817 ) 142,702 Variable rate pass-through 33,079 1,464 (6 ) 34,537 Fixed rate non-agency CMOs 15 — — 15 Fixed rate agency CMOs 284,320 37 (5,271 ) 279,086 Variable rate agency CMOs 74,274 249 (137 ) 74,386 Total residential mortgage-backed securities 536,099 2,858 (8,231 ) 530,726 Total marketable securities available-for-sale $ 800,094 3,453 (11,012 ) 792,535 Marketable securities held to maturity at December 31, 2017 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Residential mortgage-backed securities: Fixed rate pass-through $ 3,760 140 — 3,900 Variable rate pass-through 2,283 64 — 2,347 Fixed rate agency CMOs 22,906 20 (248 ) 22,678 Variable rate agency CMOs 729 13 — 742 Total residential mortgage-backed securities 29,678 237 (248 ) 29,667 Total marketable securities held-to-maturity $ 29,678 237 (248 ) 29,667 The following table presents information regarding the issuers and the carrying values of our mortgage-backed securities at December 31, 2018 and 2017 : December 31, 2018 2017 Residential mortgage backed securities: FNMA $ 288,825 286,031 GNMA 81,444 37,796 FHLMC 229,226 236,007 Other (including non-agency) 528 570 Total residential mortgage-backed securities $ 600,023 560,404 Marketable securities having a carrying value of $132.4 million at December 31, 2018 were pledged under collateral agreements. During the year ended December 31, 2018 , we sold marketable securities classified as available-for-sale for $ 5.2 million , with gross realized gains of $ 189,000 and gross realized losses of $ 37,000 . During the year ended December 31, 2017 , we sold marketable securities classified as available-for-sale for $36.8 million , with gross realized gains of $1.8 million and gross realized losses of $626,000 . 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 no gross realized losses. During the years ended December 31, 2018 , 2017 and 2016 , we did not recognize 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, 2018 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ — — 136,425 (2,449 ) 136,425 (2,449 ) Municipal securities 929 (1 ) 1,709 (10 ) 2,638 (11 ) Residential mortgage-backed securities - agency 34,031 (30 ) 346,675 (10,456 ) 380,706 (10,486 ) Total temporarily impaired securities $ 34,960 (31 ) 484,809 (12,915 ) 519,769 (12,946 ) 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, 2017 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ 5,006 (7 ) 197,695 (2,761 ) 202,701 (2,768 ) Equity securities — — 544 (6 ) 544 (6 ) Municipal securities 4,563 (7 ) — — 4,563 (7 ) Residential mortgage-backed securities - agency 239,703 (2,522 ) 202,344 (5,957 ) 442,047 (8,479 ) Total temporarily impaired securities $ 249,272 (2,536 ) 400,583 (8,724 ) 649,855 (11,260 ) 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 enhancements 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 180 positions that are temporarily impaired at December 31, 2018 . The aggregate carrying amount of cost-method investments, including both held-to-maturity and available-for-sale, at December 31, 2018 was $824.2 million , of which all were evaluated for impairment. As of December 31, 2018, there were no investment securities for which other-than-temporary impairment charges were recorded in earnings. 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, 2018 2017 Beginning balance as of January 1, (1) $ 352 7,942 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — Credit losses on debt securities for which other-than-temporary impairment was previously recognized — (7,265 ) Reduction for securities sold realized during the year (352 ) (325 ) Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — Ending balance as of December 31, $ — 352 (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, 2018
Receivables [Abstract]
Loans Receivable and Allowance for Loan Losses	Loans Receivable and Allowance for Loan Losses Loans receivable at December 31, 2018 and 2017 are summarized in the table below: December 31, 2018 December 31, 2017 Originated Acquired Total Originated Acquired Total Personal Banking: Residential mortgage loans (1) $ 2,766,430 93,782 2,860,212 2,658,726 113,823 2,772,549 Home equity loans 1,043,878 214,544 1,258,422 1,051,558 258,797 1,310,355 Consumer finance loans (2) 3,817 — 3,817 18,619 — 18,619 Consumer loans 775,378 58,671 834,049 540,832 97,877 638,709 Total Personal Banking 4,589,503 366,997 4,956,500 4,269,735 470,497 4,740,232 Commercial Banking: Commercial real estate loans 2,416,047 223,327 2,639,374 2,303,179 296,161 2,599,340 Commercial loans 612,962 48,816 661,778 572,341 60,822 633,163 Total Commercial Banking 3,029,009 272,143 3,301,152 2,875,520 356,983 3,232,503 Total loans receivable, gross 7,618,512 639,140 8,257,652 7,145,255 827,480 7,972,735 Deferred loan costs 36,820 798 37,618 26,255 1,527 27,782 Allowance for loan losses (51,751 ) (3,463 ) (55,214 ) (50,572 ) (6,223 ) (56,795 ) Undisbursed loan proceeds: Residential mortgage loans (11,513 ) — (11,513 ) (10,067 ) — (10,067 ) Commercial real estate loans (167,029 ) (524 ) (167,553 ) (141,967 ) (2,647 ) (144,614 ) Commercial loans (63,605 ) (1,160 ) (64,765 ) (51,143 ) (1,284 ) (52,427 ) Total loans receivable, net $ 7,361,434 634,791 7,996,225 6,917,761 818,853 7,736,614 (1) Includes $0 and $3.1 million of loans held for sale at December 31, 2018 and 2017 , respectively. (2) Represents loans from our consumer finance subsidiary that was closed in 2017 which are no longer being originated. As of December 31, 2018 , 2017 and 2016 , we serviced loans for others approximating $794.2 million , $887.3 million and $918.9 million , respectively. These loans serviced for others are not our assets and are not included in our financial statements. As of December 31, 2018 and 2017 , approximately 58% and 60% , 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, 2018 and 2017 include $2.810 billion and $2.856 billion , respectively, of adjustable rate loans and $5.448 billion and $5.117 billion , respectively, of fixed rate 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, 2018 2017 Acquired loans evaluated individually for future credit losses: Outstanding principal balance $ 8,189 9,735 Carrying value 5,690 6,875 Acquired loans evaluated collectively for future credit losses: Outstanding principal balance 637,170 824,205 Carrying value 632,564 818,201 Total acquired loans: Outstanding principal balance 645,359 833,940 Carrying value 638,254 825,076 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, 2016 $ 2,187 Accretion (1,318 ) Net reclassification from nonaccretable yield 671 Balance at December 31, 2017 1,540 Accretion (785 ) Net reclassification from nonaccretable yield — Balance at December 31, 2018 $ 755 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, 2018 : Carrying value Outstanding principal balance Related impairment reserve Average recorded investment in impaired loans Interest income/ accretion recognized Personal Banking: Residential mortgage loans $ 990 1,598 6 1,294 226 Home equity loans 1,008 1,959 7 1,483 157 Consumer loans 29 76 4 53 35 Total Personal Banking 2,027 3,633 17 2,830 418 Commercial Banking: Commercial real estate loans 3,584 4,471 1 4,028 358 Commercial loans 79 85 — 82 9 Total Commercial Banking 3,663 4,556 1 4,110 367 Total $ 5,690 8,189 18 6,940 785 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, 2017 : Carrying Outstanding Related Average Interest Personal Banking: Residential mortgage loans $ 1,182 1,880 24 1,251 181 Home equity loans 1,143 2,219 21 1,253 157 Consumer loans 59 160 4 97 51 Total Personal Banking 2,384 4,259 49 2,601 389 Commercial Banking: Commercial real estate loans 4,388 5,363 39 6,992 914 Commercial loans 103 113 — 177 15 Total Commercial Banking 4,491 5,476 39 7,169 929 Total $ 6,875 9,735 88 9,770 1,318 The following table provides information related to changes in the allowance for loan losses for the year ended December 31, 2018 : Balance Provision Charge-offs Recoveries Balance Originated loans Personal Banking: Residential mortgage loans $ 4,054 808 (1,067 ) 489 3,824 Home equity loans 3,184 (25 ) (1,183 ) 320 4,072 Consumer finance loans 676 (1,282 ) (2,813 ) 803 3,968 Consumer loans 10,404 12,151 (12,861 ) 2,639 8,475 Total Personal Banking 18,318 11,652 (17,924 ) 4,251 20,339 Commercial Banking: Commercial real estate loans 26,379 11,349 (6,096 ) 1,215 19,911 Commercial loans 7,054 (2,062 ) (2,675 ) 1,469 10,322 Total Commercial Banking 33,433 9,287 (8,771 ) 2,684 30,233 Total originated loans 51,751 20,939 (26,695 ) 6,935 50,572 Acquired loans Personal Banking: Residential mortgage loans 83 (61 ) (112 ) 125 131 Home equity loans 348 (23 ) (602 ) 211 762 Consumer loans 419 (335 ) (291 ) 155 890 Total Personal Banking 850 (419 ) (1,005 ) 491 1,783 Commercial Banking: Commercial real estate loans 1,996 (467 ) (1,291 ) 205 3,549 Commercial loans 617 279 (650 ) 97 891 Total Commercial Banking 2,613 (188 ) (1,941 ) 302 4,440 Total acquired loans 3,463 (607 ) (2,946 ) 793 6,223 Total $ 55,214 20,332 (29,641 ) 7,728 56,795 The following table provides information related to changes in the allowance for loan losses for the year ended December 31, 2017 : Balance Provision Charge-offs Recoveries Balance Originated loans Personal Banking: Residential mortgage loans $ 3,824 (390 ) (834 ) 392 4,656 Home equity loans 4,072 1,474 (1,080 ) 192 3,486 Consumer finance loans 3,968 8,444 (8,369 ) 448 3,445 Consumer loans 8,475 13,601 (11,128 ) 1,473 4,529 Total Personal Banking 20,339 23,129 (21,411 ) 2,505 16,116 Commercial Banking: Commercial real estate loans 19,911 (3,663 ) (1,344 ) 1,251 23,667 Commercial loans 10,322 (4,777 ) (2,462 ) 2,051 15,510 Total Commercial Banking 30,233 (8,440 ) (3,806 ) 3,302 39,177 Total originated loans 50,572 14,689 (25,217 ) 5,807 55,293 Acquired loans Personal Banking: Residential mortgage loans 131 185 (205 ) 80 71 Home equity loans 762 503 (1,179 ) 391 1,047 Consumer loans 890 765 (795 ) 267 653 Total Personal Banking 1,783 1,453 (2,179 ) 738 1,771 Commercial Banking: Commercial real estate loans 3,549 2,631 (2,830 ) 740 3,008 Commercial loans 891 978 (1,028 ) 74 867 Total Commercial Banking 4,440 3,609 (3,858 ) 814 3,875 Total acquired loans 6,223 5,062 (6,037 ) 1,552 5,646 Total $ 56,795 19,751 (31,254 ) 7,359 60,939 The following table provides information related to changes in the allowance for loan losses 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 finance loans 3,445 3,117 (3,323 ) 376 3,275 Consumer loans 4,529 5,935 (6,902 ) 1,283 4,213 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 Other consumer loans 653 1,072 (680 ) 151 110 Total Personal Banking 1,771 3,283 (2,381 ) 640 229 Business Banking: Commercial real estate loans 3,008 2,116 (1,337 ) 790 1,439 Commercial loans 867 877 (52 ) 8 34 Total Business 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 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, 2018 : 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 loan losses related to TDRs Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,864,470 4,137 15,848 — 5,382 993 — Home equity loans 1,258,422 3,532 7,075 136 4,502 1,520 4 Consumer finance loans 3,817 676 22 3 — — — Consumer loans 855,896 10,823 4,300 27 — — — Total Personal Banking 4,982,605 19,168 27,245 166 9,884 2,513 4 Commercial Banking: Commercial real estate loans 2,471,821 28,375 36,935 — 19,859 313 310 Commercial loans 597,013 7,671 8,101 — 3,865 263 74 Total Commercial Banking 3,068,834 36,046 45,036 — 23,724 576 384 Total $ 8,051,439 55,214 72,281 166 33,608 3,089 388 (1) Includes $15.3 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, 2017 : Recorded investment in loans receivable Allowance for loan losses Recorded investment in loans on nonaccrual (1) Recorded TDRs (1) Allowance Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,776,203 3,955 14,791 — 8,000 815 — Home equity loans 1,310,355 4,834 8,907 120 1,716 462 4 Consumer finance loans 18,619 3,968 199 3 — — — Consumer loans 652,770 9,365 4,673 379 — — — Total Personal Banking 4,757,947 22,122 28,570 502 9,716 1,277 4 Commercial Banking: Commercial real estate loans 2,454,726 23,460 28,473 — 15,691 1,125 235 Commercial loans 580,736 11,213 7,412 — 6,697 742 8 Total Commercial Banking 3,035,462 34,673 35,885 — 22,388 1,867 243 Total $ 7,793,409 56,795 64,455 502 32,104 3,144 247 (1) Includes $12.3 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, 2018 : 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 $ 12,965 2,883 — 6,660 22,508 20,733 910 Home equity loans 5,996 1,079 — 1,818 8,893 9,075 511 Consumer finance loans 22 — — — 22 24 Consumer loans 3,228 1,072 — — 4,300 3,992 235 Total Personal Banking 22,211 5,034 — 8,478 35,723 33,824 1,656 Commercial Banking: Commercial real estate loans 25,509 11,426 8,549 4,435 49,919 41,328 1,599 Commercial loans 3,010 5,091 2,453 2,087 12,641 9,186 507 Total Commercial Banking 28,519 16,517 11,002 6,522 62,560 50,514 2,106 Total $ 50,730 21,551 11,002 15,000 98,283 84,338 3,762 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, 2017 : 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 $ 13,509 1,282 — 6,814 21,605 21,531 892 Home equity loans 7,251 1,656 — 1,449 10,356 9,150 452 Consumer finance loans 199 — — — 199 379 20 Consumer loans 3,617 1,056 — — 4,673 4,042 188 Total Personal Banking 24,576 3,994 — 8,263 36,833 35,102 1,552 Commercial Banking: Commercial real estate loans 15,361 13,112 4,431 4,123 37,027 49,981 1,758 Commercial loans 3,140 4,272 906 2,447 10,765 12,110 672 Total Commercial Banking 18,501 17,384 5,337 6,570 47,792 62,091 2,430 Total $ 43,077 21,378 5,337 14,833 84,625 97,193 3,982 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 finance loans 743 — — — 743 772 35 Consumer loans 3,080 1,286 — — 4,366 2,931 131 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 evaluation of impaired loans by portfolio segment and by class of financing receivable as of and for the year ended December 31, 2018 : 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 $ 2,856,359 8,111 8,111 747 — Home equity loans 1,256,255 2,167 2,167 523 — Consumer finance loans 3,817 — — — — Consumer loans 855,867 29 29 6 — Total Personal Banking 4,972,298 10,307 10,307 1,276 — Commercial Banking: Commercial real estate loans 2,436,605 35,216 31,830 6,499 3,386 Commercial loans 588,932 8,081 6,738 767 1,343 Total Commercial Banking 3,025,537 43,297 38,568 7,266 4,729 Total $ 7,997,835 53,604 48,875 8,542 4,729 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, 2017 : 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 $ 2,767,635 8,568 8,568 816 — Home equity loans 1,308,639 1,716 1,716 461 — Consumer finance loans 18,619 — — — — Consumer loans 652,685 85 85 25 — Total Personal Banking 4,747,578 10,369 10,369 1,302 — Commercial Banking: Commercial real estate loans 2,433,755 20,971 18,470 1,859 2,501 Commercial loans 571,412 9,324 8,572 829 752 Total Commercial Banking 3,005,167 30,295 27,042 2,688 3,253 Total $ 7,752,745 40,664 37,411 3,990 3,253 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, in accordance with 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, 2018 2017 Number of Amount Number of Amount Beginning TDR balance: 205 $ 32,104 225 $ 42,926 New TDRs 29 1,800 24 5,450 Re-modified TDRs 6 3,086 5 2,099 Net paydowns (6,606 ) (11,538 ) Charge-offs: Residential mortgage loans 1 (135 ) 1 (77 ) Home equity loans — — 1 (48 ) Commercial real estate loans 2 (294 ) 2 (2,498 ) Commercial loans 7 (1,345 ) 6 (259 ) Paid-off loans: Residential mortgage loans 5 258 — — Home equity loans 5 83 8 (62 ) Commercial real estate loans 10 2,254 15 (1,633 ) Commercial loans 9 2,403 11 (2,256 ) Ending TDR balance: 195 $ 33,608 205 $ 32,104 Accruing TDRs $ 18,302 $ 19,819 Non-accrual TDRs 15,306 12,285 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, 2018 : Number of Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 9 $ 754 749 72 Home equity loans 17 636 610 150 Total Personal Banking 26 1,390 1,359 222 Commercial Banking: Commercial real estate loans 5 3,157 3,114 169 Commercial loans 4 339 342 69 Total Commercial Banking 9 3,496 3,456 238 Total 35 $ 4,886 4,815 460 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, 2017 : Number of Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 8 $ 1,604 1,555 158 Home equity loans 3 152 148 40 Total Personal Banking 11 1,756 1,703 198 Commercial Banking: Commercial real estate loans 11 5,232 4,889 364 Commercial loans 7 561 526 37 Total Commercial Banking 18 5,793 5,415 401 Total 29 $ 7,549 7,118 599 The following table provides information related to troubled debt restructurings (including re-modified TDRs) that have subsequently defaulted by portfolio segment and by class of financing receivable during the year ended December 31, 2017 : Number of 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 $ 336 334 34 Home equity loans — — — — Total Personal Banking 1 336 334 34 Commercial Banking: Commercial real estate loans 2 438 426 35 Commercial loans — — — — Total Business Banking 2 438 426 35 Total 3 $ 774 760 69 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 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 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 4 $ 962 958 564 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, 2018 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 9 $ 7 326 330 86 749 Home equity loans 17 64 264 90 192 610 Total Personal Banking 26 71 590 420 278 1,359 Commercial Banking: Commercial real estate loans 5 — — 3,114 — 3,114 Commercial loans 4 — — 342 — 342 Total Commercial Banking 9 — — 3,456 — 3,456 Total 35 $ 71 590 3,876 278 4,815 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, 2017 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 8 $ 359 — 8 1,188 1,555 Home equity loans 3 118 — — 30 148 Total Personal Banking 11 477 — 8 1,218 1,703 Commercial Banking: Commercial real estate loans 11 — 2,688 2,201 — 4,889 Commercial loans 7 — — 422 104 526 Total Commercial Banking 18 — 2,688 2,623 104 5,415 Total 29 $ 477 2,688 2,631 1,322 7,118 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, 2018 : Number of re-modified Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans — $ — — — — — Home equity loans — — — — — — Total Personal Banking — — — — — — Commercial Banking: Commercial real estate loans 3 — — 2,854 — 2,854 Commercial loans 3 — — 192 — 192 Total Commercial Banking 6 — — 3,046 — 3,046 Total 6 $ — — 3,046 — 3,046 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, 2017 : Number of Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 2 $ 250 — — 429 679 Home equity loans 1 12 — — — 12 Total Personal Banking 3 262 — — 429 691 Commercial Banking: Commercial real estate loans 1 — — 1,299 — 1,299 Commercial loans 1 — — 83 — 83 Total Commercial Banking 2 — — 1,382 — 1,382 Total 5 $ 262 — 1,382 429 2,073 The following table provides information related to loan delinquencies as of December 31, 2018 : 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 $ 27,245 5,732 11,668 44,645 2,714,474 2,759,119 — Home equity loans 6,810 1,771 4,825 13,406 1,030,472 1,043,878 — Consumer finance loans 661 172 21 854 2,963 3,817 — Consumer loans 9,000 2,867 3,037 14,904 793,092 807,996 — Total Personal Banking 43,716 10,542 19,551 73,809 4,541,001 4,614,810 — Commercial Banking: Commercial real estate loans 5,391 4,801 21,721 31,913 2,217,105 2,249,018 Commercial loans 609 560 2,714 3,883 545,474 549,357 Total Commercial Banking 6,000 5,361 24,435 35,796 2,762,579 2,798,375 — Total originated loans 49,716 15,903 43,986 109,605 7,303,580 7,413,185 — Acquired loans Personal Banking: Residential mortgage loans 532 693 1,317 2,542 91,240 93,782 19 Home equity loans 1,839 294 1,212 3,345 211,199 214,544 40 Consumer loans 447 175 196 818 58,651 59,469 6 Total Personal Banking 2,818 1,162 2,725 6,705 361,090 367,795 65 Commercial Banking: Commercial real estate loans 112 586 3,866 4,564 218,239 222,803 78 Commercial loans 364 — 296 660 46,996 47,656 — Total Commercial Banking 476 586 4,162 5,224 265,235 270,459 78 Total acquired loans 3,294 1,748 6,887 11,929 626,325 638,254 143 Total loans $ 53,010 17,651 50,873 121,534 7,929,905 8,051,439 143 (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 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, 2017 : 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 $ 23,786 6,030 12,613 42,429 2,619,951 2,662,380 — Home equity loans 6,094 2,333 6,043 14,470 1,037,088 1,051,558 — Consumer finance loans 2,128 1,113 199 3,440 15,179 18,619 — Consumer loans 9,762 2,834 3,274 15,870 537,496 553,366 — Total Personal Banking 41,770 12,310 22,129 76,209 4,209,714 4,285,923 — Commercial Banking: Commercial real estate loans 5,520 2,133 10,629 18,282 2,142,930 2,161,212 — Commercial loans 1,469 204 2,806 4,479 516,719 521,198 — Total Commercial Banking 6,989 2,337 13,435 22,761 2,659,649 2,682,410 — Total originated loans 48,759 14,647 35,564 98,970 6,869,363 6,968,333 — Acquired loans Personal Banking: Residential mortgage loans 1,998 205 1,277 3,480 110,343 113,823 381 Home equity loans 1,367 538 1,306 3,211 255,586 258,797 98 Consumer loans 1,150 517 353 2,020 97,384 99,404 10 Total Personal Banking 4,515 1,260 2,936 8,711 463,313 472,024 489 Commercial Banking: Commercial real estate loans 2,795 406 5,655 8,856 284,658 293,514 923 Commercial loans 396 237 334 967 58,571 59,538 — Total Commercial Banking 3,191 643 5,989 9,823 343,229 353,052 923 Total acquired loans 7,706 1,903 8,925 18,534 806,542 825,076 1,412 Total loans $ 56,465 16,550 44,489 117,504 7,675,905 7,793,409 1,412 (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 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, 2018 : Pass Special mention Substandard Doubtful Loss Total Originated loans Personal Banking: Residential mortgage loans $ 2,749,266 — 9,853 — — 2,759,119 Home equity loans 1,038,245 — 5,633 — — 1,043,878 Consumer finance loans 3,817 — — — — 3,817 Consumer loans 804,075 — 3,921 — — 807,996 Tota

Accrued Interest Receivable

Accrued Interest Receivable	12 Months Ended
	Dec. 31, 2018
Interest Receivable and Other Assets [Abstract]
Accrued Interest Receivable	Accrued Interest Receivable Accrued interest receivable as of December 31, 2018 and 2017 is presented in the following table: December 31, 2018 2017 Investment securities $ 1,035 1,260 Mortgage-backed securities 1,333 1,107 Loans receivable 22,122 20,985 $ 24,490 23,352

Federal Home Loan Bank Stock

Federal Home Loan Bank Stock	12 Months Ended
	Dec. 31, 2018
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 ("FHLB") 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 %. Our investment in the capital stock of the FHLB of Pittsburgh at December 31, 2018 and December 31, 2017 was $ 15.6 million and $ 11.7 million , respectively. We received dividends on capital stock during the years ended December 31, 2018 and 2017 of $452,000 and $250,000 , 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, 2018
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Premises and equipment at December 31, 2018 and 2017 are summarized by major classification in the following table: December 31, 2018 2017 Land and land improvements $ 21,042 21,563 Office buildings and improvements 150,328 150,056 Furniture, fixtures and equipment 119,829 125,347 Leasehold improvements 17,419 19,909 Total, at cost 308,618 316,875 Less accumulated depreciation and amortization (165,228 ) (164,931 ) Premises and equipment, net $ 143,390 151,944 Depreciation and amortization expense for the years ended December 31, 2018 , 2017 and 2016 was $12.1 million , $12.4 million and $13.7 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: 2019 $ 4,677 2020 3,884 2021 3,179 2022 2,465 2023 2,040 Thereafter 7,784 Total $ 24,029 Rental expense for the years ended December 31, 2018 , 2017 and 2016 was $5.4 million , $5.6 million and $5.3 million , respectively.

Goodwill and Other Intangible A

Goodwill and Other Intangible Assets	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 : December 31, 2018 2017 Amortizable intangible assets: Core deposit intangibles - gross $ 63,685 63,685 Acquisitions — — Less: accumulated amortization (45,027 ) (40,029 ) Core deposit intangibles - net $ 18,658 23,656 Customer and Contract intangible assets - gross $ 10,474 10,474 Acquisitions — — Less: accumulated amortization (9,311 ) (8,461 ) Customer and Contract intangible assets - net $ 1,163 2,013 The following information shows the actual aggregate amortization expense for the years ended December 31, 2018 , 2017 and 2016 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, 2016 $ 4,259 For the year ended December 31, 2017 6,764 For the year ended 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 For the year ending December 31, 2022 2,456 For the year ending December 31, 2023 1,847 The following table provides information for the changes in the carrying amount of goodwill: Total Balance at December 31, 2016 $ 307,420 Goodwill acquired — Balance at December 31, 2017 307,420 Goodwill acquired — Balance at December 31, 2018 $ 307,420 We have determined that goodwill is not impaired as of December 31, 2018 and 2017 . There were no changes in our operations that would cause us to update the goodwill impairment test performed as of June 30, 2018 .

Deposits

Deposits	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Deposits	Deposits Deposit balances at December 31, 2018 and 2017 are shown in the table below: December 31, 2018 2017 Savings deposits $ 1,636,099 1,653,579 Interest-bearing demand deposits 1,455,460 1,442,928 Noninterest-bearing demand deposits 1,736,156 1,610,409 Money market deposit accounts 1,661,623 1,707,450 Time deposits 1,404,841 1,412,623 Total deposits $ 7,894,179 7,826,989 The aggregate amount of time deposits with a minimum denomination of $100,000 at December 31, 2018 and 2017 was $460.8 million and $436.4 million , respectively. Generally, deposits in excess of $250,000 are not federally insured. At December 31, 2018 we had $1.675 billion of deposits in accounts exceeding $250,000 . The following table summarizes the contractual maturity of time deposits at December 31, 2018 and 2017 : December 31, 2018 2017 Due within 12 months $ 553,173 666,348 Due between 12 and 24 months 352,074 226,171 Due between 24 and 36 months 213,591 201,654 Due between 36 and 48 months 171,866 131,530 Due between 48 and 60 months 108,068 174,704 After 60 months 6,069 12,216 Total time deposits $ 1,404,841 1,412,623 The following table summarizes the interest expense incurred on the respective deposits for the years ended December 31, 2018 , 2017 and 2016 : Years ended December 31, 2018 2017 2016 Savings deposits $ 3,064 3,062 3,218 Interest-bearing demand deposits 3,607 1,027 462 Money market deposit accounts 5,740 4,203 3,621 Time deposits 18,574 14,765 16,164 Total interest expense $ 30,985 23,057 23,465

Borrowed Funds

Borrowed Funds	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Borrowed Funds	Borrowed Funds (a) Borrowings Borrowed funds at December 31, 2018 and 2017 are presented in the following table: December 31, 2018 2017 Amount Average rate Amount Average rate Term notes payable to the FHLB of Pittsburgh: Due within one year $ 128,600 2.60 % $ — — % Total term notes payable to FHLB of Pittsburgh 128,600 — Collateralized borrowings, due within one year 105,789 0.20 % 108,238 0.20 % Total borrowed funds $ 234,389 $ 108,238 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. At December 31, 2018 and December 31, 2017 , collateralized borrowings due within one year were $ 105.8 million and $ 108.2 million , respectively. 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, 2018 , 2017 and 2016 was $102.3 million , $121.0 million and $141.6 million , respectively. The maximum amount of collateralized borrowings outstanding during the years ended December 31, 2018 , 2017 and 2016 was $110.3 million , $137.2 million and $158.4 million , respectively. (b) Trust Preferred Securities We have three statutory business trusts: Northwest Bancorp Capital Trust III, a Delaware statutory business trust, Northwest Bancorp Statutory Trust IV, a Connecticut statutory business trust and LNB Trust II, a Delaware statutory business trusts (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. 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% . 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 and a floating rate of interest, which resets quarterly, equal to three-month LIBOR plus 1.48% . 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, 2018 was 4.18% . 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, 2018 was 4.17% . LNB Trust II holds $8,119,000 of the Company's junior subordinated debentures due June 15, 2037, with a floating rate of interest, reset quarterly, of three-month LIBOR plus 1.48% . The rate in effect at December 31, 2018 was 4.27% . 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). 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, 2018 and 2017 : Capital debt December 31, securities 2018 2017 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

Income Taxes

Income Taxes	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Income Taxes	Income Taxes Total income tax was allocated for the years ended December 31, 2018 , 2017 and 2016 as follows: Years ended December 31, 2018 2017 2016 Income before income taxes $ 28,422 41,444 21,648 Shareholders’ equity for unrealized loss on securities available-for-sale (573 ) (3,403 ) (1,871 ) Shareholders’ equity for tax benefit for excess of fair value above cost of stock benefit plans — — (1,425 ) Shareholders’ equity for pension adjustment (24 ) (213 ) (2,455 ) Shareholders’ equity for swap fair value adjustment 223 585 539 Unallocated income tax $ 28,048 38,413 16,436 Income tax expense applicable to income before taxes consists of: Years ended December 31, 2018 2017 2016 Current $ 31,192 30,127 18,914 Deferred (2,770 ) 11,317 2,734 Total income tax expense $ 28,422 41,444 21,648 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, 2018 , 2017 and 2016 , is as follows: Years ended December 31, 2018 2017 2016 Expected tax rate 21.0 % 35.0 % 35.0 % Tax-exempt interest income (0.9 )% (1.5 )% (3.3 )% State income tax, net of federal benefit 3.8 % 3.2 % 1.2 % Bank-owned life insurance (0.9 )% (1.6 )% (2.6 )% Stock-based compensation (0.8 )% (0.9 )% — % Dividends on stock plans (0.6 )% (1.1 )% (2.0 )% Low income housing and historic tax credits (0.6 )% (0.5 )% (1.0 )% ESOP termination — % — % 3.4 % Adjustment to net deferred tax liabilities for enacted changes in tax laws and rates — % (2.3 )% — % Other 0.2 % 0.2 % (0.3 )% Effective tax rate 21.2 % 30.5 % 30.4 % The tax effects of temporary differences that give rise to significant portions of the deferred tax assets and deferred tax liabilities at December 31, 2018 and 2017 are presented below: December 31, 2018 2017 Deferred tax assets: Deferred rent $ 115 87 Deferred compensation expense 2,357 1,040 Bad debts 11,257 10,277 Other reserves 1,065 953 Accrued postretirement benefit cost 410 413 Stock benefit plans 904 744 Writedown of investment securities — 104 Accrued expenses — 35 Pension and postretirement benefits 13,057 13,033 Unrealized loss on the fair value of derivatives — 223 Unrealized loss on the fair value of securities available-for-sale 2,733 2,160 Deferred income 822 1,001 Other 219 141 Total deferred tax assets 32,939 30,211 Deferred tax liabilities: Pension expense 5,686 5,542 Purchase accounting 180 303 Intangible assets 13,839 13,546 Mortgage servicing rights 460 777 Fixed assets 4,602 4,940 Net deferred loan costs 4,558 4,690 Other 331 274 Total deferred tax liabilities 29,656 30,072 Net deferred tax asset $ 3,283 139 We recorded a valuation allowance against state deferred tax assets of a Northwest subsidiary since the subsidiary is not expected to utilize its deferred tax assets in the foreseeable future. This valuation allowance is netted against other deferred tax assets in the preceding table. Other than stated above, 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 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, 2018 , 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, 2018 , we did not accrue any interest. At December 31, 2018 , 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, 2018 , 2017 , 2016 and 2015 and subject to audit by any state in which we conduct business for the tax periods ended December 31, 2018 , 2017 , 2016 and 2015 . The New York State audit of the Company's 2011 to 2014 tax years was finalized in 2016, resulting in an additional tax liability of $ 444,000 . The Internal Revenue Service audit of the 2013 tax year of LNB was concluded in 2016 and resulted in no additional tax liability. Effective January 1, 2018 the Tax Cuts and Jobs Act of 2017 reduced our corporate federal tax rate from 35.0% to 21.0% . As a result, on the enactment date of December 22, 2017, we were required to re-measure, through income tax expense, our deferred tax assets and liabilities using the enacted rate at which we expect them to be recovered or settled. This re-measurement of our net deferred tax liability resulted in prior year 2017 income tax benefit of $ 3.1 million . Also on December 22, 2017, the U.S. Securities and Exchange Commission (“SEC”) released Staff Accounting Bulletin No. 118 (“SAB 118”) to address any uncertainty or diversity of views in practice in accounting for the income tax effects of the Act in situations where a registrant does not have the necessary information available, prepared, or analyzed in reasonable detail to complete this accounting in the reporting period that includes the enactment date. SAB 118 allows for a measurement period not to extend beyond one year from the Act’s enactment date to complete the necessary accounting. We recorded provisional amounts of deferred income taxes using reasonable estimates in three areas where information necessary to complete the accounting was not available, prepared, or analyzed: (i) our deferred tax asset for temporary differences associated with accrued compensation was awaiting final determinations of amounts that will be paid on or before March 15, 2019 and deducted on the 2018 income tax returns;(ii) our deferred tax liability for temporary differences associated with equity investments in partnerships was awaiting receipt of Schedules K-1 from outside preparers, which was necessary to determine our 2018 tax impact from these investments; (iii) we made no adjustments until further analysis can be completed to deferred tax assets representing future deductions for accrued compensation that may be subject to new limitations under Internal Revenue Code Section 162(m) which generally, limits the annual deduction for certain compensation paid to certain employees to $1 million.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 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, 2018
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 years ended December 31, 2018 , 2017 and 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 $17.20 , $16.64 , and $ 14.79 , respectively. The computation of basic and diluted earnings per share for the years ended December 31, 2018 , 2017 and 2016 follows: Years ended December 31, 2018 2017 2016 Net income available to common shareholders $ 105,491 94,467 49,667 Weighted average common shares outstanding 102,073,888 101,015,083 99,439,174 Dilutive potential shares due to effect of stock options 1,492,013 1,549,822 1,225,514 Total weighted average common shares and dilutive potential shares 103,565,901 102,564,905 100,664,688 Basic earnings per share (1) $ 1.03 0.94 0.50 Diluted earnings per share (1) $ 1.02 0.92 0.49 (1) Not in thousands.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [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 100% of each employee’s contribution to a maximum of 4% of the employee’s compensation. Total expense for all retirement plans, including defined benefit pension plans, was approximately $5.8 million , $6.8 million and $5.8 million , for the years ended December 31, 2018 , 2017 and 2016 , 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, 2018 , 2017 and 2016 : Years ended December 31, 2018 2017 2016 Service cost $ 6,864 6,149 5,496 Interest cost 6,712 6,879 6,781 Expected return on plan assets (11,968 ) (10,512 ) (9,897 ) Net amortization and deferral 1,167 1,388 1,388 Net periodic pension cost $ 2,775 3,904 3,768 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, 2018 2017 2016 Net (gain)/loss $ (1,716 ) (1,647 ) 1,550 Prior service cost — — — Amortization of prior service cost 2,323 2,323 2,323 Total recognized in other comprehensive income $ 607 676 3,873 Total recognized in net periodic pension cost and other comprehensive income $ 3,382 4,580 7,641 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 $3.3 million and $(2.3) million , respectively. The following table sets forth information for the defined benefit pension plans’ funded status at December 31, 2018 and 2017 : December 31, 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 193,142 172,208 Service cost 6,864 6,149 Interest cost 6,712 6,879 Actuarial (gain)/loss (19,015 ) 14,807 Benefits paid (6,582 ) (6,901 ) Benefit obligation at end of year $ 181,121 193,142 Change in plan assets: Fair value of plan assets at beginning of year $ 173,668 152,625 Actual return on plan assets (8,820 ) 23,255 Employer contributions 2,500 4,689 Benefits paid (6,582 ) (6,901 ) Fair value of plan assets at end of period $ 160,766 173,668 Funded status at end of year $ (20,355 ) (19,474 ) The following table sets forth the assumptions used to develop the net periodic pension cost: Years ended December 31, 2018 2017 2016 Discount rate 3.53 % 4.06 % 4.25 % Expected long-term rate of return on assets 7.00 % 7.00 % 7.00 % 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, 2018 2017 2016 Discount rate 4.15 % 3.53 % 4.06 % Expected long-term rate of return on assets 7.00 % 7.00 % 7.00 % 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 $175.1 million , $186.9 million and $165.9 million at December 31, 2018 , 2017 and 2016 , respectively. The accumulated benefit obligation for all unfunded defined benefit plans was $4.8 million , $6.2 million and $6.3 million at December 31, 2018 , 2017 and 2016 , respectively. The following table sets forth certain information related to our pension plans: December 31, 2018 2017 Projected benefit obligation $ 181,121 193,142 Accumulated benefit obligation 181,121 193,142 Fair value of plan assets 160,766 173,668 We anticipate making a contribution to our defined benefit pension plan of $2.0 million to $4.0 million during the year ending December 31, 2019 . 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 2018 2017 Debt securities 20 – 50% 27 % 23 % Equity securities 30 – 60% 70 % 73 % Other 5 – 50% 3 % 4 % 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 15. The following table sets forth the pension plan assets as of December 31, 2018 and 2017 : December 31, 2018 2017 Mutual funds - debt $ 43,549 40,010 Mutual funds - equity 112,580 125,871 Cash and cash equivalents 4,637 7,787 The benefits expected to be paid in each year from 2019 to 2023 are $7.2 million , $7.5 million , $7.8 million , $7.7 million and $7.8 million , respectively. The aggregate benefits expected to be paid in the five years from 2024 to 2028 are $44.1 million . The expected benefits to be paid are based on the same assumptions used to measure our benefit obligations at December 31, 2018 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, 2018 , 2017 and 2016 : Years ended December 31, 2018 2017 2016 Interest cost $ 54 68 70 Amortization of net loss 98 108 90 Net period benefit cost $ 152 176 160 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, 2018 2017 2016 Net (gain)/loss $ (305 ) (156 ) 109 Total recognized in other comprehensive income $ (305 ) (156 ) 109 Total recognized in net periodic benefit cost and other comprehensive (loss)/income $ (153 ) 20 269 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 year ending December 31, 2019 is $68,000 . The following table sets forth the funded status of the postretirement healthcare benefit plan at December 31, 2018 and 2017 : December 31, 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 1,637 1,779 Interest cost 54 68 Actuarial loss (207 ) (48 ) Benefits paid (152 ) (162 ) Benefit obligation at end of year $ 1,332 1,637 Change in plan assets: Employer contributions 152 162 Benefits paid (152 ) (162 ) Funded status at year end $ (1,332 ) (1,637 ) The assumptions used to develop the preceding information for postretirement healthcare benefits are as follows: Years ended December 31, 2018 2017 2016 Discount rate 3.53 % 4.06 % 4.25 % Monthly cost of healthcare insurance per beneficiary (1) $ 507 548 539 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 $7,000 and the accumulated postretirement benefit obligation for healthcare benefits would increase by $43,000 . The following table sets forth information for plans with an accumulated benefit obligation in excess of plan assets: December 31, 2018 2017 Projected benefit obligation $ 1,332 1,637 Accumulated benefit obligation 1,332 1,637 (c) Employee Stock Ownership Plan On September 30, 2016, the Northwest Savings Bank Employee Stock Ownership Plan ("ESOP") was terminated and merged into the Northwest Bank 401(k) Plan. ESOP compensation expense was $6.3 million for the year ended December 31, 2016 . Compensation expense related to the ESOP was 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 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). On May 17, 2017, we awarded employees 378,050 common shares and outside directors 24,300 common shares with a grant date fair value of $15.24 per share (total market value of $5.8 million at issuance). On May 14, 2018, we awarded employees 390,030 common shares and outside directors 24,300 common shares with a grant date fair value of $16.59 per share (total market value of $6.9 million at issuance). Total common shares forfeited from the 2011 plan were 415,154 , of which, 496,091 shares were forfeited during the year ended December 31, 2018 . Forfeited shares may be awarded to other eligible recipients in future grants until the plan termination date in 2021. Common shares vest over a 7 -year period with the first vesting occurring on the grant date. As of December 31, 2018 , 30% of the 2016 issuances have vested, 20% of the 2017 issuances have vested and 10% of the 2018 issuances have vested. (e) Stock Option Plans The Northwest Bancshares, Inc. 2011 Equity Incentive Plan also authorizes the granting of 7,015,583 stock options. On May 18, 2016, we granted employees 660,600 stock options and outside directors 64,800 stock options with an exercise price of $14.15 per share. On May 17, 2017, we granted employees 754,210 stock options and outside directors 64,800 stock options with an exercise price of $15.57 per share. On May 14, 2018, we granted employees 831,160 stock options and outside directors 64,800 stock options with an exercise price of $16.59 per share. Awarded stock options vest over a seven -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, 2018 , 2017 and 2016 (amounts in this table are not in thousands): Years ended December 31, 2018 2017 2016 Number Weighted average exercise price Number Weighted average exercise price Number Weighted average exercise price Balance at beginning of year 5,695,570 $ 12.75 5,804,105 $ 12.25 6,306,496 $ 11.81 Granted (1) 895,960 16.59 819,010 15.57 725,400 14.15 Exercised (2) (830,712 ) 10.38 (630,591 ) 11.66 (1,081,072 ) 11.01 Forfeited/expired (148,006 ) 12.52 (296,954 ) 12.43 (146,719 ) 12.71 Balance at end of year 5,612,812 13.49 5,695,570 12.75 5,804,105 12.25 Exercisable at end of year 3,016,175 12.61 3,016,367 11.99 3,035,718 11.71 (1) Weighted average fair value of options at grant date: $1.49 , $1.55 and $1.52 , respectively. (2) The total intrinsic value of options exercised was $4.8 million , $3.5 million and $5.1 million , respectively. The aggregate intrinsic value of all options expected to vest and fully vested options at December 31, 2018 is $8.6 million and $14.3 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, 2018 : Exercise Exercise Exercise Exercise Exercise Exercise Exercise Options outstanding: Number of options 106,041 2,250 869,718 205,326 339,197 246,618 8,500 Weighted average remaining contract life (years) 1.00 0.25 9.25 2.00 3.25 3.00 2.25 Options exercisable: Number of options 106,041 2,250 156,040 211,239 246,865 255,741 7,000 Weighted average remaining term - vested (years) 1.00 0.25 9.25 2.00 3.25 3.00 2.25 Exercise Exercise Exercise Exercise Exercise Exercise Total Options outstanding: Number of options 1,289,238 457,852 385,906 393,497 589,728 718,941 5,612,812 Weighted average remaining contract life (years) 2.25 6.25 4.25 5.25 7.25 8.25 5.36 Options exercisable: Number of options 1,023,261 194,851 245,720 207,164 191,970 168,033 3,016,175 Weighted average remaining term - vested (years) 2.25 6.25 4.25 5.25 7.25 8.25 3.97

Disclosures About Fair Value of

Disclosures About Fair Value of Financial Instruments	12 Months Ended
	Dec. 31, 2018
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. Interest Rate and Foreign Exchange Swap Agreements The fair value of interest rate swaps is based upon the present value of the expected future cash flows using the LIBOR swap curve, the basis for the underlying interest rate. To price interest rate swaps, cash flows are first projected for each payment date using the fixed rate for the fixed side of the swap and the forward rates for the floating side of the swap. These swap cash flows are then discounted to time zero using LIBOR zero-coupon interest rates. The sum of the present value of both legs is the fair market value of the interest rate swap. These valuations have been derived from our third party vendor’s proprietary models rather than actual market quotations. The proprietary models are based upon financial principles and assumptions that we believe to be reasonable. The fair value of the foreign exchange swap is derived from proprietary models rather than actual market quotations. The proprietary models are based upon financial principles and assumptions we believe to be reasonable. 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, 2018 and 2017 , 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, 2018 and 2017 : December 31, 2018 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 68,789 68,789 68,789 — — Securities available-for-sale 801,450 801,450 — 801,450 — Securities held-to-maturity 22,765 22,446 — 22,446 — Loans receivable, net 7,996,225 7,845,313 — — 7,845,313 Accrued interest receivable 24,490 24,490 24,490 — — Interest rate swaps 6,445 6,445 — 6,445 — FHLB Stock 15,635 15,635 — — — Total financial assets $ 8,935,799 8,784,568 93,279 830,341 7,845,313 Financial liabilities: Savings and checking accounts $ 6,489,338 6,489,338 6,489,338 — — Time deposits 1,404,841 1,434,410 — — 1,434,410 Borrowed funds 234,389 234,389 234,389 — — Junior subordinated debentures 111,213 102,572 — — 102,572 Interest rate swaps 6,445 6,445 — 6,445 — Accrued interest payable 744 744 744 — — Total financial liabilities $ 8,246,970 8,267,898 6,724,471 6,445 1,536,982 December 31, 2017 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 77,710 77,710 77,710 — — Securities available-for-sale 792,535 792,535 574 791,961 — Securities held-to-maturity 29,678 29,667 — 29,667 — Loans receivable, net 7,736,614 7,762,562 3,128 — 7,759,434 Accrued interest receivable 23,352 23,352 23,352 — — Interest rate swaps 214 214 — 214 — FHLB Stock 11,733 11,733 — — — Total financial assets $ 8,671,836 8,697,773 104,764 821,842 7,759,434 Financial liabilities: Savings and checking accounts $ 6,414,366 6,414,366 6,414,366 — — Time deposits 1,412,623 1,433,380 — — 1,433,380 Borrowed funds 108,238 108,238 108,238 — — Junior subordinated debentures 111,213 110,954 — — 110,954 Interest rate swaps 1,278 1,278 — 1,278 — Foreign exchange swaps 61 61 — 61 — Accrued interest payable 460 460 460 — — Total financial liabilities $ 8,048,239 8,068,737 6,523,064 1,339 1,544,334 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, 2018 and 2017 . There were no transfers of financial instruments between Level 1 and Level 2 during the years ended December 31, 2018 and 2017 . The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2018 : Level 1 Level 2 Level 3 Total at fair value Assets Equity securities $ — — — — Debt securities: U.S. government and agencies — 14,780 — 14,780 Government sponsored enterprises — 187,335 — 187,335 States and political subdivisions — 21,163 — 21,163 Corporate — 914 — 914 Total debt securities — 224,192 — 224,192 Residential mortgage-backed securities: GNMA — 27,041 — 27,041 FNMA — 73,196 — 73,196 FHLMC — 51,621 — 51,621 Non-agency — 528 — 528 Collateralized mortgage obligations: GNMA — 52,331 — 52,331 FNMA — 207,033 — 207,033 FHLMC — 165,508 — 165,508 Non-agency — — — — Total mortgage-backed securities — 577,258 — 577,258 Interest rate swaps — 6,445 — 6,445 Total assets $ — 807,895 — 807,895 Liabilities Interest rate swaps $ — 6,445 — 6,445 Total liabilities $ — 6,445 — 6,445 The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2017 : Level 1 Level 2 Level 3 Total at fair value Assets Equity securities $ 574 — — 574 Debt securities: U.S. government and agencies — 1 — 1 Government sponsored enterprises — 209,269 — 209,269 States and political subdivisions — 51,056 — 51,056 Corporate — 909 — 909 Total debt securities — 261,235 — 261,235 Residential mortgage-backed securities: GNMA — 29,695 — 29,695 FNMA — 82,969 — 82,969 FHLMC — 64,021 — 64,021 Non-agency — 555 — 555 Collateralized mortgage obligations: GNMA — 4,769 — 4,769 FNMA — 191,512 — 191,512 FHLMC — 157,190 — 157,190 SBA — — — — Non-agency — 15 — 15 Total mortgage-backed securities — 530,726 — 530,726 Interest rate swaps — 214 — 214 Total assets $ 574 792,175 — 792,749 Liabilities Interest rate swaps $ — 1,278 — 1,278 Foreign exchange swaps — 61 — 61 Total liabilities $ — 1,339 — 1,339 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, 2018 and 2017 : December 31, 2018 2017 Debt securities Beginning balance January 1, $ — 9,366 Total net realized investment gains and net change in unrealized appreciation: Included in net income as OTTI — — Included in other comprehensive income — 1,282 Purchases — — Sales (10,648 ) Transfers into Level 3 — — Transfers out of Level 3 — — Ending balance December 31, $ — — 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, 2018 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 40,333 40,333 Real estate owned — — 2,498 2,498 Total assets $ — — 42,831 42,831 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, 2017 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 33,421 33,421 Real estate owned — — 5,666 5,666 Total assets $ — — 39,087 39,087 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. For the years ending December 31, 2018 and 2017, the fair market value of all mortgage servicing rights exceeded their carrying value. 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, 2018 : Fair value Valuation techniques Significant unobservable inputs Range (weighted average) Loans measured for impairment $ 40,333 Appraisal Estimated costs to sell 10% value (1) Discounted cash Discount rate 4.25% to 10.0% (7.50%) flow Real estate owned 2,498 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 Requirements

Regulatory Capital Requirements	12 Months Ended
	Dec. 31, 2018
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. 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 Total, Tier 1 and Common Equity Tier 1 ("CET1") capital to risk-weighted assets in addition to the amount necessary to meet its minimum risk-based capital requirements. 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, 2018 and 2017 , we and our banking subsidiary exceeded all capital adequacy requirements to which we were subject. As of December 15, 2018 , 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, 2018 and 2017 were as follows: At December 31, 2018 Minimum capital Well capitalized Actual requirements (1) requirements Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,183,619 15.833 % $ 738,212 9.875 % $ 747,557 10.000 % Northwest Bank 1,026,027 13.736 % 737,647 9.875 % 746,984 10.000 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,128,405 15.095 % 588,701 7.875 % 598,045 8.000 % Northwest Bank 970,813 12.996 % 588,250 7.875 % 597,587 8.000 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,020,530 13.652 % 476,567 6.375 % 485,912 6.500 % Northwest Bank 970,813 12.996 % 476,202 6.375 % 448,190 6.000 % Tier 1 capital (leverage) (to average assets) Northwest Bancshares, Inc. 1,128,405 11.899 % 379,342 4.000 % 474,177 5.000 % Northwest Bank 970,813 10.240 % 379,236 4.000 % 474,045 5.000 % (1) Amounts and ratios include the 2018 capital conservation buffer of 1.875% with the exception of Tier 1 capital to average assets. For further information related to the capital conservation buffer, see Item 1. Business - "Supervision and Regulation". At December 31, 2017 Minimum capital Well capitalized Actual requirements (1) requirements Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,136,076 15.831 % $ 663,823 9.250 % $ 71,747 10.000 % Northwest Bank 1,017,251 14.189 % 663,179 9.250 % 716,951 10.000 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,079,270 15.039 % 520,294 7.250 % 574,117 8.000 % Northwest Bank 960,443 13.396 % 519,789 7.250 % 573,560 8.000 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 971,395 13.536 % 412,647 5.750 % 466,470 6.500 % Northwest Bank 960,443 13.396 % 412,247 5.750 % 430,170 6.000 % Tier I capital (leverage) (to average assets) Northwest Bancshares, Inc. 1,079,270 11.676 % 369,735 4.000 % 462,169 5.000 % Northwest Bank 960,443 10.400 % 369,482 4.000 % 461,853 5.000 % (1) Amounts and ratios include the 2017 capital conservation buffer of 1.250% with the exception of Tier 1 capital to average assets. For further information related to the capital conservation buffer, see Item 1. Business - "Supervision and Regulation".

Contingent Liabilities

Contingent Liabilities	12 Months Ended
	Dec. 31, 2018
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, 2018
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, 2018 , we have not accrued for legal proceedings based on our analysis of currently available information which is 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. During the year-ended December 31, 2018, Northwest and our subsidiary, Northwest Insurance Services (“NWIS”), were involved in a lawsuit against, among others, First National Bank of Pennsylvania (“FNB”) and their insurance subsidiary, First National Insurance Agency, LLC (“FNIA”). All counterclaims against Northwest were discontinued and, on Friday, December 21, 2018, a verdict was rendered in favor of NWIS on several of its claims. Post-trial proceedings continue and, due to the inherent uncertainties with respect to these proceedings, we have not accrued any awards associated with this verdict within our consolidated financial statements as of December 31, 2018.

Components of Accumulated Other

Components of Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 : December 31, 2018 2017 Unrealized gain on marketable securities available-for-sale $ (6,832 ) (4,409 ) Fair value of interest rate swaps — (691 ) Defined benefit pension plans (32,864 ) (26,980 ) Accumulated other comprehensive income $ (39,696 ) (32,080 ) The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2018 : 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, $ (4,409 ) (691 ) (26,980 ) (32,080 ) Reclassification due to adoption of ASU No. 2018-02 (991 ) (149 ) (5,606 ) (6,746 ) Other comprehensive income/(loss) before reclassification adjustments (1,277 ) 840 (1,181 ) (1,618 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (155 ) — 903 748 Net other comprehensive income/(loss) (2,423 ) 691 (5,884 ) (7,616 ) Balance as of December 31, $ (6,832 ) — (32,864 ) (39,696 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $215 , net of tax (income tax expense) of $60 . (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 $(3,568) , net of tax (income tax expense) of $361 . The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2017 : 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, $ 395 (1,778 ) (26,608 ) (27,991 ) Other comprehensive income/(loss) before reclassification adjustments (2,478 ) 1,087 (1,254 ) (2,645 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (2,326 ) — 882 (1,444 ) Net other comprehensive income/(loss) (4,804 ) 1,087 (372 ) (4,089 ) Balance as of December 31, $ (4,409 ) (691 ) (26,980 ) (32,080 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $3,814 net of tax (income tax expense) of $1,488 . (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 $(3,818) , net of tax (income tax expense) of $613 . 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 losses 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 .

Parent Company Only Financial S

Parent Company Only Financial Statements - Condensed	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Parent Company Only Financial Statements - Condensed	Parent Company Only Financial Statements - Condensed Statements of Financial Condition December 31, 2018 2017 Assets Cash and cash equivalents $ 155,524 26,088 Marketable securities available-for-sale — 545 Investment in bank subsidiary 1,211,258 1,200,799 Other assets 2,298 92,712 Total assets $ 1,369,080 1,320,144 Liabilities and Shareholders’ Equity Liabilities: Debentures payable $ 111,213 111,213 Other liabilities 230 1,207 Total liabilities 111,443 112,420 Shareholders’ equity 1,257,637 1,207,724 Total liabilities and shareholders’ equity $ 1,369,080 1,320,144 Statements of Income Years ended December 31, 2018 2017 2016 Income: Interest income $ 198 137 737 Other income 752 2,297 709 Dividends from bank subsidiary 105,000 90,000 50,000 Undistributed earnings from equity investment in bank subsidiary 5,149 7,255 2,760 Total income 111,099 99,689 54,206 Expense: Compensation and benefits 1,225 1,282 1,129 Other expense 660 553 561 Interest expense 4,961 4,666 4,560 Total expense 6,846 6,501 6,250 Income before income taxes 104,253 93,188 47,956 Federal and state income taxes (1,238 ) (1,279 ) (1,711 ) Net income $ 105,491 94,467 49,667 Statements of Cash Flows Years ended December 31, 2018 2017 2016 Operating activities: Net income $ 105,491 94,467 49,667 Adjustments to reconcile net income to net cash provided by operating activities: Undistributed earnings of subsidiary (5,149 ) (7,255 ) (2,760 ) Noncash stock benefit plan compensation expense — 4,894 10,916 Gain on sale of marketable securities (146 ) (1,615 ) (43 ) Net change in other assets and liabilities 91,520 (43,513 ) (63,533 ) Net cash provided by/(used in) operating activities 191,716 46,978 (5,753 ) Investing activities: Net (Purchase)/sale of marketable securities (550 ) 2,800 (1,952 ) Net cash provided by/(used in) investing activities (550 ) 2,800 (1,952 ) Financing activities: Cash dividends paid (69,921 ) (65,212 ) (60,156 ) Share repurchases — — (1,752 ) Repayment of loan to ESOP — — 797 Excess tax benefit from stock-based compensation — — 1,425 Proceeds from options exercised 8,191 7,001 10,856 Net cash used in financing activities (61,730 ) (58,211 ) (48,830 ) Net increase/(decrease) in cash and cash equivalents $ 129,436 (8,433 ) (56,535 ) Cash and cash equivalents at beginning of year $ 26,088 34,521 91,056 Net increase/(decrease) in cash and cash equivalents 129,436 (8,433 ) (56,535 ) Cash and cash equivalents at end of year $ 155,524 26,088 34,521

Derivative Financial Instrument

Derivative Financial Instruments	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative Financial Instruments	Derivative Financial Instruments We are a party to derivative financial instruments in the normal course of business to manage our own exposure to fluctuations in interest rates and to meet the needs of our customers. The primary derivatives that we use are interest rate swaps and caps and foreign exchange contracts, which are entered into with counterparties that meet established credit standards. We believe that the credit risk inherent in all of our derivative contracts is minimal based on our credit standards and the netting and collateral provisions of the interest rate swap agreements. (a) Derivatives Designated in Hedging Relationships With the expiration of the $50.0 million in notional of interest rate swap agreements (swaps) previously designated in hedging relationships, we are no longer a counterparty to any interest rate swap agreements designated as cash flow hedges. Previously, the swaps were intended to protect against the variability of cash flows associated with Northwest Bancorp Capital Trust III and Northwest Bancorp Capital Trust IV. In 2018, the swaps matured without replacement. (b) Derivatives Not Designated in Hedge Relationships In addition to our derivatives designated in hedge relationships, we act as an interest rate or foreign exchange swap counterparty for certain commercial borrowers in the normal course of servicing our customers, which are accounted for at fair value. We manage our exposure to such interest rate or foreign exchange swaps by entering into corresponding and offsetting interest rate swaps with third parties that mirror the terms of the swaps we have with the commercial borrowers. These positions (referred to as “customer swaps”) directly offset each other and our exposure is the fair value of the derivatives due to changes in credit risk of our commercial borrowers and third parties. Customer swaps are recorded within other assets or other liabilities on the consolidated statement of financial condition at their estimated fair value. Changes to the fair value of assets and liabilities arising from these derivatives are included, net, in other operating income in the consolidated statement of income. The following table presents information regarding our derivative financial instruments, at December 31, : Asset derivatives Liability derivatives Notional amount Fair value Notional amount Fair value 2018: Derivatives designated as hedging instruments: Interest rate swap agreements $ — — — — Derivatives not designated as hedging instruments: Interest rate swap agreements 221,919 6,445 221,919 6,445 Foreign exchange swap agreements — — — — Total derivatives $ 221,919 6,445 221,919 6,445 2017: Derivatives designated as hedging instruments: Interest rate swap agreements $ — — 50,000 1,064 Derivatives not designated as hedging instruments: Interest rate swap agreements 92,631 214 92,631 214 Foreign exchange swap agreements — — 12,344 61 Total derivatives $ 92,631 214 154,975 1,339 The following table indicates the gain or loss recognized in income on derivatives for the periods indicated: For the years ended December 31, 2018 2017 2016 Non-hedging swap derivatives: Increase/(decrease) in other income $ (288 ) (373 ) — Hedging interest rate derivatives: Increase in interest expense 949 1,599 1,866

Selected Quarterly Financial Da

Selected Quarterly Financial Data - Unaudited	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Selected Quarterly Financial Data - Unaudited	Selected Quarterly Financial Data - Unaudited Quarters ended March 31, June 30, September 30, December 31, (In thousands, except per share data) 2018: Interest income $ 89,533 92,875 95,605 97,768 Interest expense 7,766 8,649 9,788 10,937 Net interest income 81,767 84,226 85,817 86,831 Provision for loan losses 4,209 5,349 6,982 3,792 Noninterest income 21,788 24,109 22,557 23,248 Noninterest expenses 67,421 69,787 66,617 72,273 Income before income taxes 31,925 33,199 34,775 34,014 Income tax expense 6,940 6,900 7,035 7,547 Net income $ 24,985 26,299 27,740 26,467 Basic earnings per share $ 0.25 0.26 0.27 0.26 Diluted earnings per share $ 0.24 0.25 0.27 0.26 Quarters ended March 31, June 30, September 30, December 31, (In thousands, except per share data) 2017: Interest income $ 87,267 89,797 90,231 91,561 Interest expense 6,690 7,066 6,994 7,321 Net interest income 80,577 82,731 83,237 84,240 Provision for loan losses 4,637 5,562 3,027 6,525 Noninterest income 21,504 41,477 24,594 22,905 Noninterest expenses 71,646 73,262 68,799 71,896 Income before income taxes 25,798 45,384 36,005 28,724 Income tax expense 8,052 14,402 12,414 6,576 Net income $ 17,746 30,982 23,591 22,148 Basic earnings per share $ 0.18 0.31 0.23 0.22 Diluted earnings per share $ 0.17 0.30 0.23 0.22 Quarters ended March 31, June 30, September 30, 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

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2018
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 172 banking locations in Pennsylvania, New York, and Ohio.
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 statements of financial condition and 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 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 during the years ended December 31, 2018 and 2017 . 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.
Loans Receivable	Loans Receivable Our loan segments consist of Personal Banking and Business Banking loans. Personal Banking loans include residential mortgage, home equity and consumer loans. Business Banking loans include commercial real estate and commercial loans. 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 income when it has been determined that all principal and interest will be collected or are applied to principal when collectability of contractual 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 borrower is experiencing financial difficulties and the restructuring constitutes a concession. 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, 2018 and 2017 , there were $0 and $3.1 million of residential mortgage loans classified as held for sale, respectively. Acquired loans are initially measured 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 incurred losses, adjusted for a loss emergence 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.
Restricted Investment in Federal Home Loan Bank Stock	Restricted Investment in Federal Home Loan Bank Stock 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. FHLB stock is carried at cost and evaluated or impairment based on the ultimate recoverability of the par value. FHLB stock can only be purchased, redeemed and transferred at par value. Dividends are reported in interest income in the Consolidated Statements of 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 our reportable segments or one level below. 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. 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. In testing goodwill for impairment, we have the option to first assess qualitative factors to determine whether it is more likely than not that the fair value of a reporting unit is less than its carrying value. If, after assessing all events and circumstances, we determine it is not more likely than not that the fair value of a reporting unit is less than its carrying value, then performing the two-step impairment test would be unnecessary. However, if we conclude otherwise, it would then be required to perform the first step of the goodwill impairment test, and continue to the second step, if necessary. Step 1 requires the fair value of each reporting unit be compared to its carrying amount, including goodwill. 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. We conducted our annual impairment assessment as of June 30, 2018 by first performing a qualitative assessment of goodwill to determine if it was more likely than not that the fair value was less than the carrying value. In performing a qualitative analysis, factors considered include, but are not limited to, macroeconomic conditions, industry and market conditions and overall financial performance. The results of the qualitative assessment for 2018 indicated that it was not more likely than not that the fair value of the reporting unit was less than the carrying value. Consequently, no additional quantitative two-step impairment test was required and no impairment was recorded in 2018. As of June 30, 2017, we performed a quantitative impairment test that did not result in any impairment. Future events could cause us to conclude that goodwill has become impaired, which would result in recording an impairment loss. There were no changes in our operations that would cause us to update the assessment performed as of June 30, 2018 and 2017. Accordingly, we have determined that goodwill is not impaired as of December 31, 2018 and 2017.
Core Deposit and Other Identifiable Intangibles	Core Deposit 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 seven to eleven years.
Bank-Owned Life Insurance	Bank-Owned Life Insurance We own insurance on the lives of a certain group of current and former 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 covered by 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. The effect on deferred tax assets and liabilities with regard to a change in tax rates is recognized in the tax provision in the period the change is enacted.
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.
Segment Reporting	Segment Reporting As a result of the closure of the Northwest Consumer Discount Company in the third quarter 2017, we have determined that we have one reportable segment beginning in the fourth quarter 2017. The Company provides services traditionally offered by full-service community banks, including business and personal deposit accounts and business and personal loans, as well as insurance, brokerage and investment management and trust services. The Company’s non-banking activities are immaterial and, therefore, separate information has not been disclosed.
Derivative financial instruments	Derivative financial instruments 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. At times, 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 which is subsequently reclassified into earnings in the period that the hedged forecasted transaction affects earnings. The ineffective portion of the unrealized gain or loss, if any, would be recorded in other expense. For derivatives that are not designated as hedging instruments, any gain or loss is recognized immediately in earnings.
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, pension 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	(a) Recently Adopted Accounting Standards In May 2014 the Financial Accounting Standards Board (“FASB”) issued Accounting Standards Update (“ASU”) 2014-09, “Revenue from Contracts with Customers (Topic 606)”. Effective January 1, 2018, we adopted the ASU and all related amendments to all contracts using the modified retrospective approach, with the cumulative effect recorded as an adjustment to opening retained earnings. Due to immateriality, we had no cumulative effect to record. The comparative information has not been restated and continues to be reported under the accounting standards in effect for those periods. We expect the impact of the adoption of the new standard to be immaterial to our net income on an ongoing basis. Our revenue is comprised of net interest income on financial assets and financial liabilities, which is explicitly excluded from the scope of ASU 2014-09, and non-interest income. The services that fall within the scope of ASC 606 include service charges and fees, trust and other financial services income, insurance commission income, sale of OREO and other operating income. Revenue is recognized when performance obligations under the terms of a contract with our customers are satisfied. Revenue is measured as the amount of consideration we expect to receive in exchange for transferring goods or providing services. The majority of our revenue continues to be recognized at the point in time when the services are provided to our customers. Service charges and fees represents income earned on both loan and deposit accounts as well as interchange income. Service charges on deposit accounts primarily consist of overdraft, non-sufficient funds, ATM transaction fees and account management fees. Revenue is recognized at the point in time the transaction occurs or the service is provided to the customer. We earn interchange income from debit and credit cardholder transactions processed through payment networks. Interchange fees represent a percentage of the underlying transaction value and are generally set by the credit card associations. Interchange fees are recognized as transactions occur. We provide trust management services and investment management services to our customers and recognize revenue as these management services are provided. Trust and investment management services are billed and paid on a monthly or quarterly basis. Additionally, we earn commissions on investment products that are sold to our customers. These commissions are recognized at the time of the sale of the third party’s product or services to our customers. Our insurance subsidiary is an employee benefits and property and casualty insurance agency specializing in commercial and personal insurance as well as retirement benefit plans. Insurance commission income is recognized at the time of sale of the third party’s product or service to our customers. Loss on real estate owned represents gains and losses on real estate acquired by Northwest through the foreclosure process. Proceeds from the sale of these properties are recognized when control of the property transfers to the buyer. In certain instances the Bank may finance a portion of the purchase price paid by the buyer and an additional evaluation of whether all of the contract criteria are met is required. If it is not probable that we will collect substantially all of the consideration expected, the transaction would not be accounted for as a sale until the concerns about collectability are resolved. Other operating income consists primarily of revenues earned for providing transaction services to our deposit customers. The revenue is earned at the point in time the transaction occurs. We have evaluated the nature of our contracts with customers and determined that further disaggregation of revenue from contracts with customers into more granular categories beyond what is presented in the Consolidated Statements of Income was not necessary. 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. This guidance is effective for fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. We adopted this guidance as of January 1, 2018 which did not have a material impact on our results of operations and financial position. 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. Accordingly, we refined the calculation used to determine the disclosed fair value of our loans held for investment portfolio as part of adopting this standard. The refined calculation did not have a significant impact on our fair value disclosures. Refer to note 9, "Disclosures About Fair Value of Financial Instruments". In August 2016, the FASB issued ASU No. 2016-15, “ Classification of Certain Cash Receipts and Cash Payments ”. The main objective of this ASU is to reduce diversity in practice in how certain transactions are classified in the statement of cash flows. The amendments in this Update provide guidance on the following eight specific cash flow issues: debt prepayment or debt extinguishment costs, settlement of zero-coupon debt instruments, contingent consideration payments made after a business combination, proceeds from the settlement of insurance claims, proceeds from the settlement of bank-owned life insurance (BOLI) policies, distributions received from equity method investments, beneficial interests in securitization transactions, and separately identifiable cash flows and application of the predominance principle. This guidance is effective for interim and annual reporting periods in fiscal years beginning after December 15, 2017. We adopted this guidance as of January 1, 2018 and applied it on a retrospective basis. No material reclassifications were made for the year ended December 31, 2017. In January 2017, the FASB issued ASU No. 2017-01, “Business Combinations (Topic 805): Clarifying the Definition of a Business”. This guidance provides a more robust framework to use in determining when a set of assets and activities (“set”) is a business and to address stakeholder feedback that the definition of a business in current GAAP is applied too broadly. The primary amendments in the ASU provide a screen to exclude transactions where substantially all of the fair value of the transferred set is concentrated in a single asset, or group of similar assets, from being evaluated as a business. We adopted this standard on January 1, 2018 and will apply the guidance to future transactions. In January 2017, the FASB issued ASU 2017-04, "Intangibles - Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment" . This guidance eliminates the requirement to determine the fair value of individual assets and liabilities of a reporting unit to measure goodwill impairment. Under this guidance goodwill impairment testing will be performed by comparing the fair value of the reporting unit with its carrying amount and recognizing an impairment charge for the amount by which the carrying amount exceeds the reporting unit's fair value. This guidance is effective for annual and interim goodwill impairment tests in fiscal years beginning after December 15, 2019, and should be applied on a prospective basis. Early adoption is permitted for annual and interim goodwill impairment testing dates after January 1, 2017.We have elected to early adopt this standard as of January 1, 2018 and the amendments were applied on a prospective basis. The adoption did not have a material impact on the consolidated financial statements. In March 2017, the FASB issued ASU 2017-08, "Receivables - Nonrefundable Fees and Other Costs (Subtopic 310-20): Premium Amortization on Purchased Callable Debt Securities". This guidance shortens the amortization period for certain callable debt securities held at a premium to the earliest call date from the maturity date. This guidance is effective for annual and interim periods beginning after December 15, 2018. Early adoption is permitted in any interim period. We have elected to early adopt this standard as of January 1, 2018. The adoption did not have a material impact on our results of operations or financial position. In May 2017, the FASB issued ASU 2017-09, “Compensation - Stock Compensation (Topic 718) - Scope of Modification Accounting”. This guidance clarifies when changes to the terms or conditions of a share-based payment award must be accounted for as a modification. Under ASU 2017-09, an entity will not apply modification accounting to a share-based payment award if all of the following are the same immediately before and after the change: (i) the award's fair value, (ii) the award's vesting conditions and (iii) the award's classification as an equity or liability instrument. This guidance is effective for annual and interim periods beginning after December 15, 2017 and should be applied on a prospective basis to an award modified on or after the adoption date. We adopted this standard as of January 1, 2018 and will apply the guidance to future modifications. In March 2017, the FASB issued ASU No. 2017-07, “Compensation Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Costs and Net Periodic Postretirement Benefit Costs ". This guidance provides financial statement users with clearer and disaggregated information related to the components of net periodic benefit cost and improve transparency of the presentation of net periodic benefit cost in the financial statements. Employers will present the service cost component of net periodic benefit cost in the same income statement line item as other employee compensation costs arising from services rendered during the period. Employers will present the other components of the net periodic benefit cost separately from the line items that includes the service cost outside of any subtotal of operating income, if one is presented. This guidance is effective for annual and interim periods beginning after December 15, 2017 and should be applied retrospectively. We adopted this standard as of January 1, 2018. The other components of the net periodic benefit cost for the year ended December 31, 2017 and December 31, 2016 totaled $2.1 million and $1.6 million , respectively, and were reclassified from compensation and employee benefits to other expense. In February 2018, the FASB issued ASU 2018-02, " Income Statement - Reporting Comprehensive Income (Topic 220)-Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income." This guidance permits a reclassification from accumulated other comprehensive income to retained earnings of the stranded tax effects resulting from the Tax Cuts and Jobs Act. This guidance is effective for annual or interim reporting periods beginning after December 15, 2018, but permits early adoption in a period for which financial statements have not been issued. We have elected to early adopt the ASU as of January 1, 2018. The reclassification from accumulated other comprehensive income to retained earnings was $6.7 million for the release of stranded income tax benefits relating to the unrealized net gains and losses on available for sale securities and the change in fair value of our interest rate swaps and our pension plan. Our policy for releasing income tax effects from accumulated other comprehensive income is to release them when investments are sold or matured and liabilities are extinguished. (b) Recently Issued Accounting Standards 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 will utilized the transition method included in ASU 2018-11 which will allow us to apply ASU 2016-02 at the adoption date, as opposed to at the beginning of the earliest period presented. Our reporting for periods prior to January 1, 2019 will continue to be in accordance with Leases (Topic 840). We have elected to apply the package of practical expedients, which, among other things, allows for the carry forward of the historical lease classification for leases that commenced before the effective date, and the ability to use hindsight in evaluating lessee options to extend or terminate a lease. We lease certain branch and office facilities or land under operating leases. Based on our evaluation, the right-of-use asset and corresponding lease obligation liability is expected to be approximately $40 million to $45 million . The Company does not believe the new lease standard will materially affect its consolidated net income. 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 and instead requires 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 assets 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 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. Management created a formal working group to govern the implementation of these amendments consisting of key stakeholders from finance, risk, credit and accounting. We are currently in the process of designing current expected credit loss estimation methodologies and systems, and collecting data to be able to comply with the standard. We have engaged with a third-party to assist in the development of certain portfolio-level estimation methodologies and have chosen a third-party software platform provider. We are also evaluating the effect this guidance will have on our results of operations, financial position and related disclosures. The impact of the ASU will depend upon the state of the economy and the nature of our portfolios, among other items, at the date of adoption. In August 2018, the FASB issued ASU 2018-13, “Fair Value Measurement (Topic 820) - Disclosure Framework Changes to the Disclosure Requirements for Fair Value Measurement.” This guidance removes, modifies and adds disclosure requirements for fair value measurements. This guidance is effective for annual periods beginning after December 15, 2019, including interim periods within those years, with early adoption permitted for any removed or modified disclosure requirements. Transition is on a prospective basis for the new and modified disclosures, and on a retrospective basis for disclosures that have been eliminated. We do not expect this guidance to have a material impact on our financial statements. In August 2018, the FASB issued ASU 2018-14, “Compensation - Retirement Benefits - Defined Benefit Plans General (Subtopic 715-20) - Disclosure Framework-Changes to the Disclosure Requirements for Defined Benefit Plans.” This guidance removes and adds disclosure requirements for defined benefit pension or other post-retirement plans. This guidance is effective for annual periods beginning after December 15, 2020, with early adoption permitted, and requires retrospective adoption for all periods presented. We do not expect this guidance to have a material impact on our financial statements. In August 2018, the FASB issued ASU 2018-15, “Intangibles-Goodwill and Other-Internal-Use Software (Subtopic 350-40)-Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract.” This guidance aligns the requirements for capitalization of implementation costs incurred in a hosting arrangement that is a service contract with the existing guidance for internal-use software. This guidance is effective for annual periods beginning after December 15, 2019, including interim periods within those years, with early adoption permitted. Transition can either be on a retrospective basis or a prospective basis on all implementation costs incurred after the date of adoption. We are evaluating the impact this new accounting guidance will have on our financial statements.

Marketable Securities (Tables)

Marketable Securities (Tables)	12 Months Ended
	Dec. 31, 2018
Investments, Debt and Equity Securities [Abstract]
Schedule of the portfolio of investment securities available-for-sale	Marketable securities available-for-sale at December 31, 2017 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 $ 1 — — 1 Debt issued by government sponsored enterprises: Due in one year or less 66,566 14 (289 ) 66,291 Due after one year through five years 140,624 — (2,402 ) 138,222 Due after five years through ten years — — — — Due after ten years 4,833 — (77 ) 4,756 Equity securities 551 29 (6 ) 574 Municipal securities: Due in one year or less 2,492 7 (1 ) 2,498 Due after one year through five years 7,072 82 (6 ) 7,148 Due after five years through ten years 14,576 171 — 14,747 Due after ten years 26,371 292 — 26,663 Corporate debt issues: Due after ten years 909 — — 909 Residential mortgage-backed securities: Fixed rate pass-through 144,411 1,108 (2,817 ) 142,702 Variable rate pass-through 33,079 1,464 (6 ) 34,537 Fixed rate non-agency CMOs 15 — — 15 Fixed rate agency CMOs 284,320 37 (5,271 ) 279,086 Variable rate agency CMOs 74,274 249 (137 ) 74,386 Total residential mortgage-backed securities 536,099 2,858 (8,231 ) 530,726 Total marketable securities available-for-sale $ 800,094 3,453 (11,012 ) 792,535 Marketable securities available-for-sale at December 31, 2018 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 through five years $ 14,756 24 — 14,780 Debt issued by government sponsored enterprises: 3 Due in one year or less 85,089 — (795 ) 84,294 Due in one year through five years 101,078 71 (1,512 ) 99,637 Due after ten years 3,546 — (142 ) 3,404 Municipal securities: Due in one year or less 1,333 2 (6 ) 1,329 Due in one year through five years 3,985 54 (4 ) 4,035 Due in five years through ten years 10,603 60 — 10,663 Due after ten years 5,105 31 — 5,136 Corporate debt issues: Due in five years through ten years 914 — — 914 Residential mortgage-backed securities: Fixed rate pass-through 130,172 568 (4,113 ) 126,627 Variable rate pass-through 24,761 1,003 (5 ) 25,759 Fixed rate agency CMOs 365,427 865 (5,921 ) 360,371 Variable rate agency CMOs 64,246 280 (25 ) 64,501 Total residential mortgage-backed securities 584,606 2,716 (10,064 ) 577,258 Total marketable securities available-for-sale $ 811,015 2,958 (12,523 ) 801,450
Schedule of the portfolio of investment securities held-to-maturity	Marketable securities held to maturity at December 31, 2018 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Residential mortgage-backed securities: Fixed rate pass-through $ 2,896 53 — 2,949 Variable rate pass-through 1,666 39 — 1,705 Fixed rate agency CMOs 17,552 — (422 ) 17,130 Variable rate agency CMOs 651 11 — 662 Total residential mortgage-backed securities 22,765 103 (422 ) 22,446 Total marketable securities held-to-maturity $ 22,765 103 (422 ) 22,446 Marketable securities held to maturity at December 31, 2017 are as follows: Amortized cost Gross unrealized holding gains Gross unrealized holding losses Fair value Residential mortgage-backed securities: Fixed rate pass-through $ 3,760 140 — 3,900 Variable rate pass-through 2,283 64 — 2,347 Fixed rate agency CMOs 22,906 20 (248 ) 22,678 Variable rate agency CMOs 729 13 — 742 Total residential mortgage-backed securities 29,678 237 (248 ) 29,667 Total marketable securities held-to-maturity $ 29,678 237 (248 ) 29,667
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, 2018 and 2017 : December 31, 2018 2017 Residential mortgage backed securities: FNMA $ 288,825 286,031 GNMA 81,444 37,796 FHLMC 229,226 236,007 Other (including non-agency) 528 570 Total residential mortgage-backed securities $ 600,023 560,404
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, 2018 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ — — 136,425 (2,449 ) 136,425 (2,449 ) Municipal securities 929 (1 ) 1,709 (10 ) 2,638 (11 ) Residential mortgage-backed securities - agency 34,031 (30 ) 346,675 (10,456 ) 380,706 (10,486 ) Total temporarily impaired securities $ 34,960 (31 ) 484,809 (12,915 ) 519,769 (12,946 ) 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, 2017 : Less than 12 months 12 months or more Total Unrealized Unrealized Unrealized Fair value loss Fair value loss Fair value loss Government sponsored enterprises $ 5,006 (7 ) 197,695 (2,761 ) 202,701 (2,768 ) Equity securities — — 544 (6 ) 544 (6 ) Municipal securities 4,563 (7 ) — — 4,563 (7 ) Residential mortgage-backed securities - agency 239,703 (2,522 ) 202,344 (5,957 ) 442,047 (8,479 ) Total temporarily impaired securities $ 249,272 (2,536 ) 400,583 (8,724 ) 649,855 (11,260 )
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, 2018 2017 Beginning balance as of January 1, (1) $ 352 7,942 Credit losses on debt securities for which other-than-temporary impairment was not previously recognized — — Credit losses on debt securities for which other-than-temporary impairment was previously recognized — (7,265 ) Reduction for securities sold realized during the year (352 ) (325 ) Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized — — Ending balance as of December 31, $ — 352 (1) The beginning balance represents credit losses included in other-than-temporary impairment charges recognized on debt securities in prior periods.

Loans Receivable and Allowanc_2

Loans Receivable and Allowance for Loan Losses (Tables)	12 Months Ended
	Dec. 31, 2018
Receivables [Abstract]
Summary of loans receivable	Loans receivable at December 31, 2018 and 2017 are summarized in the table below: December 31, 2018 December 31, 2017 Originated Acquired Total Originated Acquired Total Personal Banking: Residential mortgage loans (1) $ 2,766,430 93,782 2,860,212 2,658,726 113,823 2,772,549 Home equity loans 1,043,878 214,544 1,258,422 1,051,558 258,797 1,310,355 Consumer finance loans (2) 3,817 — 3,817 18,619 — 18,619 Consumer loans 775,378 58,671 834,049 540,832 97,877 638,709 Total Personal Banking 4,589,503 366,997 4,956,500 4,269,735 470,497 4,740,232 Commercial Banking: Commercial real estate loans 2,416,047 223,327 2,639,374 2,303,179 296,161 2,599,340 Commercial loans 612,962 48,816 661,778 572,341 60,822 633,163 Total Commercial Banking 3,029,009 272,143 3,301,152 2,875,520 356,983 3,232,503 Total loans receivable, gross 7,618,512 639,140 8,257,652 7,145,255 827,480 7,972,735 Deferred loan costs 36,820 798 37,618 26,255 1,527 27,782 Allowance for loan losses (51,751 ) (3,463 ) (55,214 ) (50,572 ) (6,223 ) (56,795 ) Undisbursed loan proceeds: Residential mortgage loans (11,513 ) — (11,513 ) (10,067 ) — (10,067 ) Commercial real estate loans (167,029 ) (524 ) (167,553 ) (141,967 ) (2,647 ) (144,614 ) Commercial loans (63,605 ) (1,160 ) (64,765 ) (51,143 ) (1,284 ) (52,427 ) Total loans receivable, net $ 7,361,434 634,791 7,996,225 6,917,761 818,853 7,736,614 (1) Includes $0 and $3.1 million of loans held for sale at December 31, 2018 and 2017 , respectively. (2) Represents loans from our consumer finance subsidiary that was closed in 2017 which are no longer being originated.
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, 2018 2017 Acquired loans evaluated individually for future credit losses: Outstanding principal balance $ 8,189 9,735 Carrying value 5,690 6,875 Acquired loans evaluated collectively for future credit losses: Outstanding principal balance 637,170 824,205 Carrying value 632,564 818,201 Total acquired loans: Outstanding principal balance 645,359 833,940 Carrying value 638,254 825,076
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, 2016 $ 2,187 Accretion (1,318 ) Net reclassification from nonaccretable yield 671 Balance at December 31, 2017 1,540 Accretion (785 ) Net reclassification from nonaccretable yield — Balance at December 31, 2018 $ 755
Schedule of the composition of impaired loans by portfolio segment and by class of financing receivable	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, 2018 : 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 $ 12,965 2,883 — 6,660 22,508 20,733 910 Home equity loans 5,996 1,079 — 1,818 8,893 9,075 511 Consumer finance loans 22 — — — 22 24 Consumer loans 3,228 1,072 — — 4,300 3,992 235 Total Personal Banking 22,211 5,034 — 8,478 35,723 33,824 1,656 Commercial Banking: Commercial real estate loans 25,509 11,426 8,549 4,435 49,919 41,328 1,599 Commercial loans 3,010 5,091 2,453 2,087 12,641 9,186 507 Total Commercial Banking 28,519 16,517 11,002 6,522 62,560 50,514 2,106 Total $ 50,730 21,551 11,002 15,000 98,283 84,338 3,762 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, 2017 : 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 $ 13,509 1,282 — 6,814 21,605 21,531 892 Home equity loans 7,251 1,656 — 1,449 10,356 9,150 452 Consumer finance loans 199 — — — 199 379 20 Consumer loans 3,617 1,056 — — 4,673 4,042 188 Total Personal Banking 24,576 3,994 — 8,263 36,833 35,102 1,552 Commercial Banking: Commercial real estate loans 15,361 13,112 4,431 4,123 37,027 49,981 1,758 Commercial loans 3,140 4,272 906 2,447 10,765 12,110 672 Total Commercial Banking 18,501 17,384 5,337 6,570 47,792 62,091 2,430 Total $ 43,077 21,378 5,337 14,833 84,625 97,193 3,982 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 finance loans 743 — — — 743 772 35 Consumer loans 3,080 1,286 — — 4,366 2,931 131 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 purchased credit impaired loans by portfolio segment and by class of financing receivable at and for the year ended December 31, 2018 : Carrying value Outstanding principal balance Related impairment reserve Average recorded investment in impaired loans Interest income/ accretion recognized Personal Banking: Residential mortgage loans $ 990 1,598 6 1,294 226 Home equity loans 1,008 1,959 7 1,483 157 Consumer loans 29 76 4 53 35 Total Personal Banking 2,027 3,633 17 2,830 418 Commercial Banking: Commercial real estate loans 3,584 4,471 1 4,028 358 Commercial loans 79 85 — 82 9 Total Commercial Banking 3,663 4,556 1 4,110 367 Total $ 5,690 8,189 18 6,940 785 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, 2017 : Carrying Outstanding Related Average Interest Personal Banking: Residential mortgage loans $ 1,182 1,880 24 1,251 181 Home equity loans 1,143 2,219 21 1,253 157 Consumer loans 59 160 4 97 51 Total Personal Banking 2,384 4,259 49 2,601 389 Commercial Banking: Commercial real estate loans 4,388 5,363 39 6,992 914 Commercial loans 103 113 — 177 15 Total Commercial Banking 4,491 5,476 39 7,169 929 Total $ 6,875 9,735 88 9,770 1,318
Schedule of the changes in the allowance for losses on loans receivable	The following table provides information related to changes in the allowance for loan losses for the year ended December 31, 2018 : Balance Provision Charge-offs Recoveries Balance Originated loans Personal Banking: Residential mortgage loans $ 4,054 808 (1,067 ) 489 3,824 Home equity loans 3,184 (25 ) (1,183 ) 320 4,072 Consumer finance loans 676 (1,282 ) (2,813 ) 803 3,968 Consumer loans 10,404 12,151 (12,861 ) 2,639 8,475 Total Personal Banking 18,318 11,652 (17,924 ) 4,251 20,339 Commercial Banking: Commercial real estate loans 26,379 11,349 (6,096 ) 1,215 19,911 Commercial loans 7,054 (2,062 ) (2,675 ) 1,469 10,322 Total Commercial Banking 33,433 9,287 (8,771 ) 2,684 30,233 Total originated loans 51,751 20,939 (26,695 ) 6,935 50,572 Acquired loans Personal Banking: Residential mortgage loans 83 (61 ) (112 ) 125 131 Home equity loans 348 (23 ) (602 ) 211 762 Consumer loans 419 (335 ) (291 ) 155 890 Total Personal Banking 850 (419 ) (1,005 ) 491 1,783 Commercial Banking: Commercial real estate loans 1,996 (467 ) (1,291 ) 205 3,549 Commercial loans 617 279 (650 ) 97 891 Total Commercial Banking 2,613 (188 ) (1,941 ) 302 4,440 Total acquired loans 3,463 (607 ) (2,946 ) 793 6,223 Total $ 55,214 20,332 (29,641 ) 7,728 56,795 The following table provides information related to changes in the allowance for loan losses for the year ended December 31, 2017 : Balance Provision Charge-offs Recoveries Balance Originated loans Personal Banking: Residential mortgage loans $ 3,824 (390 ) (834 ) 392 4,656 Home equity loans 4,072 1,474 (1,080 ) 192 3,486 Consumer finance loans 3,968 8,444 (8,369 ) 448 3,445 Consumer loans 8,475 13,601 (11,128 ) 1,473 4,529 Total Personal Banking 20,339 23,129 (21,411 ) 2,505 16,116 Commercial Banking: Commercial real estate loans 19,911 (3,663 ) (1,344 ) 1,251 23,667 Commercial loans 10,322 (4,777 ) (2,462 ) 2,051 15,510 Total Commercial Banking 30,233 (8,440 ) (3,806 ) 3,302 39,177 Total originated loans 50,572 14,689 (25,217 ) 5,807 55,293 Acquired loans Personal Banking: Residential mortgage loans 131 185 (205 ) 80 71 Home equity loans 762 503 (1,179 ) 391 1,047 Consumer loans 890 765 (795 ) 267 653 Total Personal Banking 1,783 1,453 (2,179 ) 738 1,771 Commercial Banking: Commercial real estate loans 3,549 2,631 (2,830 ) 740 3,008 Commercial loans 891 978 (1,028 ) 74 867 Total Commercial Banking 4,440 3,609 (3,858 ) 814 3,875 Total acquired loans 6,223 5,062 (6,037 ) 1,552 5,646 Total $ 56,795 19,751 (31,254 ) 7,359 60,939 The following table provides information related to changes in the allowance for loan losses 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 finance loans 3,445 3,117 (3,323 ) 376 3,275 Consumer loans 4,529 5,935 (6,902 ) 1,283 4,213 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 Other consumer loans 653 1,072 (680 ) 151 110 Total Personal Banking 1,771 3,283 (2,381 ) 640 229 Business Banking: Commercial real estate loans 3,008 2,116 (1,337 ) 790 1,439 Commercial loans 867 877 (52 ) 8 34 Total Business 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
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, 2018 : 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 loan losses related to TDRs Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,864,470 4,137 15,848 — 5,382 993 — Home equity loans 1,258,422 3,532 7,075 136 4,502 1,520 4 Consumer finance loans 3,817 676 22 3 — — — Consumer loans 855,896 10,823 4,300 27 — — — Total Personal Banking 4,982,605 19,168 27,245 166 9,884 2,513 4 Commercial Banking: Commercial real estate loans 2,471,821 28,375 36,935 — 19,859 313 310 Commercial loans 597,013 7,671 8,101 — 3,865 263 74 Total Commercial Banking 3,068,834 36,046 45,036 — 23,724 576 384 Total $ 8,051,439 55,214 72,281 166 33,608 3,089 388 (1) Includes $15.3 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, 2017 : Recorded investment in loans receivable Allowance for loan losses Recorded investment in loans on nonaccrual (1) Recorded TDRs (1) Allowance Additional commitments to customers with loans classified as TDRs Personal Banking: Residential mortgage loans $ 2,776,203 3,955 14,791 — 8,000 815 — Home equity loans 1,310,355 4,834 8,907 120 1,716 462 4 Consumer finance loans 18,619 3,968 199 3 — — — Consumer loans 652,770 9,365 4,673 379 — — — Total Personal Banking 4,757,947 22,122 28,570 502 9,716 1,277 4 Commercial Banking: Commercial real estate loans 2,454,726 23,460 28,473 — 15,691 1,125 235 Commercial loans 580,736 11,213 7,412 — 6,697 742 8 Total Commercial Banking 3,035,462 34,673 35,885 — 22,388 1,867 243 Total $ 7,793,409 56,795 64,455 502 32,104 3,144 247 (1) Includes $12.3 million of nonaccrual TDRs.
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, 2018 : 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 $ 2,856,359 8,111 8,111 747 — Home equity loans 1,256,255 2,167 2,167 523 — Consumer finance loans 3,817 — — — — Consumer loans 855,867 29 29 6 — Total Personal Banking 4,972,298 10,307 10,307 1,276 — Commercial Banking: Commercial real estate loans 2,436,605 35,216 31,830 6,499 3,386 Commercial loans 588,932 8,081 6,738 767 1,343 Total Commercial Banking 3,025,537 43,297 38,568 7,266 4,729 Total $ 7,997,835 53,604 48,875 8,542 4,729 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, 2017 : 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 $ 2,767,635 8,568 8,568 816 — Home equity loans 1,308,639 1,716 1,716 461 — Consumer finance loans 18,619 — — — — Consumer loans 652,685 85 85 25 — Total Personal Banking 4,747,578 10,369 10,369 1,302 — Commercial Banking: Commercial real estate loans 2,433,755 20,971 18,470 1,859 2,501 Commercial loans 571,412 9,324 8,572 829 752 Total Commercial Banking 3,005,167 30,295 27,042 2,688 3,253 Total $ 7,752,745 40,664 37,411 3,990 3,253
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, 2018 2017 Number of Amount Number of Amount Beginning TDR balance: 205 $ 32,104 225 $ 42,926 New TDRs 29 1,800 24 5,450 Re-modified TDRs 6 3,086 5 2,099 Net paydowns (6,606 ) (11,538 ) Charge-offs: Residential mortgage loans 1 (135 ) 1 (77 ) Home equity loans — — 1 (48 ) Commercial real estate loans 2 (294 ) 2 (2,498 ) Commercial loans 7 (1,345 ) 6 (259 ) Paid-off loans: Residential mortgage loans 5 258 — — Home equity loans 5 83 8 (62 ) Commercial real estate loans 10 2,254 15 (1,633 ) Commercial loans 9 2,403 11 (2,256 ) Ending TDR balance: 195 $ 33,608 205 $ 32,104 Accruing TDRs $ 18,302 $ 19,819 Non-accrual TDRs 15,306 12,285
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, 2018 : Number of Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 9 $ 754 749 72 Home equity loans 17 636 610 150 Total Personal Banking 26 1,390 1,359 222 Commercial Banking: Commercial real estate loans 5 3,157 3,114 169 Commercial loans 4 339 342 69 Total Commercial Banking 9 3,496 3,456 238 Total 35 $ 4,886 4,815 460 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, 2017 : Number of Recorded investment at the time of modification Current recorded investment Current allowance Troubled debt restructurings: Personal Banking: Residential mortgage loans 8 $ 1,604 1,555 158 Home equity loans 3 152 148 40 Total Personal Banking 11 1,756 1,703 198 Commercial Banking: Commercial real estate loans 11 5,232 4,889 364 Commercial loans 7 561 526 37 Total Commercial Banking 18 5,793 5,415 401 Total 29 $ 7,549 7,118 599 The following table provides information related to troubled debt restructurings (including re-modified TDRs) that have subsequently defaulted by portfolio segment and by class of financing receivable during the year ended December 31, 2017 : Number of 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 $ 336 334 34 Home equity loans — — — — Total Personal Banking 1 336 334 34 Commercial Banking: Commercial real estate loans 2 438 426 35 Commercial loans — — — — Total Business Banking 2 438 426 35 Total 3 $ 774 760 69 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 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 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 4 $ 962 958 564
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, 2018 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 9 $ 7 326 330 86 749 Home equity loans 17 64 264 90 192 610 Total Personal Banking 26 71 590 420 278 1,359 Commercial Banking: Commercial real estate loans 5 — — 3,114 — 3,114 Commercial loans 4 — — 342 — 342 Total Commercial Banking 9 — — 3,456 — 3,456 Total 35 $ 71 590 3,876 278 4,815 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, 2017 : Number of Type of modification contracts Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 8 $ 359 — 8 1,188 1,555 Home equity loans 3 118 — — 30 148 Total Personal Banking 11 477 — 8 1,218 1,703 Commercial Banking: Commercial real estate loans 11 — 2,688 2,201 — 4,889 Commercial loans 7 — — 422 104 526 Total Commercial Banking 18 — 2,688 2,623 104 5,415 Total 29 $ 477 2,688 2,631 1,322 7,118
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, 2018 : Number of re-modified Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans — $ — — — — — Home equity loans — — — — — — Total Personal Banking — — — — — — Commercial Banking: Commercial real estate loans 3 — — 2,854 — 2,854 Commercial loans 3 — — 192 — 192 Total Commercial Banking 6 — — 3,046 — 3,046 Total 6 $ — — 3,046 — 3,046 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, 2017 : Number of Type of re-modification TDRs Rate Payment Maturity date Other Total Personal Banking: Residential mortgage loans 2 $ 250 — — 429 679 Home equity loans 1 12 — — — 12 Total Personal Banking 3 262 — — 429 691 Commercial Banking: Commercial real estate loans 1 — — 1,299 — 1,299 Commercial loans 1 — — 83 — 83 Total Commercial Banking 2 — — 1,382 — 1,382 Total 5 $ 262 — 1,382 429 2,073
Schedule of loan delinquencies	The following table provides information related to loan delinquencies as of December 31, 2018 : 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 $ 27,245 5,732 11,668 44,645 2,714,474 2,759,119 — Home equity loans 6,810 1,771 4,825 13,406 1,030,472 1,043,878 — Consumer finance loans 661 172 21 854 2,963 3,817 — Consumer loans 9,000 2,867 3,037 14,904 793,092 807,996 — Total Personal Banking 43,716 10,542 19,551 73,809 4,541,001 4,614,810 — Commercial Banking: Commercial real estate loans 5,391 4,801 21,721 31,913 2,217,105 2,249,018 Commercial loans 609 560 2,714 3,883 545,474 549,357 Total Commercial Banking 6,000 5,361 24,435 35,796 2,762,579 2,798,375 — Total originated loans 49,716 15,903 43,986 109,605 7,303,580 7,413,185 — Acquired loans Personal Banking: Residential mortgage loans 532 693 1,317 2,542 91,240 93,782 19 Home equity loans 1,839 294 1,212 3,345 211,199 214,544 40 Consumer loans 447 175 196 818 58,651 59,469 6 Total Personal Banking 2,818 1,162 2,725 6,705 361,090 367,795 65 Commercial Banking: Commercial real estate loans 112 586 3,866 4,564 218,239 222,803 78 Commercial loans 364 — 296 660 46,996 47,656 — Total Commercial Banking 476 586 4,162 5,224 265,235 270,459 78 Total acquired loans 3,294 1,748 6,887 11,929 626,325 638,254 143 Total loans $ 53,010 17,651 50,873 121,534 7,929,905 8,051,439 143 (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 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, 2017 : 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 $ 23,786 6,030 12,613 42,429 2,619,951 2,662,380 — Home equity loans 6,094 2,333 6,043 14,470 1,037,088 1,051,558 — Consumer finance loans 2,128 1,113 199 3,440 15,179 18,619 — Consumer loans 9,762 2,834 3,274 15,870 537,496 553,366 — Total Personal Banking 41,770 12,310 22,129 76,209 4,209,714 4,285,923 — Commercial Banking: Commercial real estate loans 5,520 2,133 10,629 18,282 2,142,930 2,161,212 — Commercial loans 1,469 204 2,806 4,479 516,719 521,198 — Total Commercial Banking 6,989 2,337 13,435 22,761 2,659,649 2,682,410 — Total originated loans 48,759 14,647 35,564 98,970 6,869,363 6,968,333 — Acquired loans Personal Banking: Residential mortgage loans 1,998 205 1,277 3,480 110,343 113,823 381 Home equity loans 1,367 538 1,306 3,211 255,586 258,797 98 Consumer loans 1,150 517 353 2,020 97,384 99,404 10 Total Personal Banking 4,515 1,260 2,936 8,711 463,313 472,024 489 Commercial Banking: Commercial real estate loans 2,795 406 5,655 8,856 284,658 293,514 923 Commercial loans 396 237 334 967 58,571 59,538 — Total Commercial Banking 3,191 643 5,989 9,823 343,229 353,052 923 Total acquired loans 7,706 1,903 8,925 18,534 806,542 825,076 1,412 Total loans $ 56,465 16,550 44,489 117,504 7,675,905 7,793,409 1,412 (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 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.
Schedule of credit quality indicators	The following table sets forth information about credit quality indicators as of December 31, 2018 : Pass Special mention Substandard Doubtful Loss Total Originated loans Personal Banking: Residential mortgage loans $ 2,749,266 — 9,853 — — 2,759,119 Home equity loans 1,038,245 — 5,633 — — 1,043,878 Consumer finance loans 3,817 — — — — 3,817 Consumer loans 804,075 — 3,921 — — 807,996 Total Personal Banking 4,595,403 — 19,407 — — 4,614,810 Commercial Banking: Commercial real estate loans 2,062,728 91,142 95,148 — — 2,249,018 Commercial loans 503,665 15,760 29,932 — — 549,357 Total Commercial Banking 2,566,393 106,902 125,080 — — 2,798,375 Total originated loans 7,161,796 106,902 144,487 — — 7,413,185 Acquired loans Personal Banking: Residential mortgage loans 92,625 — 1,157 — — 93,782 Home equity loans 213,273 — 1,271 — — 214,544 Consumer loans 58,954 — 515 — 59,469 Total Personal Banking 364,852 — 2,943 — — 367,795 Commercial Banking: Commercial real estate loans 191,622 3,546 27,635 — — 222,803 Commercial loans 35,397 3,521 8,738 — — 47,656 Total Commercial Banking 227,019 7,067 36,373 — — 270,459 Total acquired loans 591,871 7,067 39,316 — — 638,254 Total loans $ 7,753,667 113,969 183,803 — — 8,051,439 The following table sets forth information about credit quality indicators as of December 31, 2017 : Pass Special mention Substandard Doubtful Loss Total Originated loans Personal Banking: Residential mortgage loans $ 2,645,475 — 16,905 — — 2,662,380 Home equity loans 1,042,965 — 8,593 — — 1,051,558 Consumer finance loans 18,420 — 199 — — 18,619 Consumer loans 549,550 — 3,816 — — 553,366 Total Personal Banking 4,256,410 — 29,513 — — 4,285,923 Commercial Banking: Commercial real estate loans 1,964,565 78,699 117,948 — — 2,161,212 Commercial loans 461,962 15,510 43,726 — — 521,198 Total Commercial Banking 2,426,527 94,209 161,674 — — 2,682,410 Total originated loans 6,682,937 94,209 191,187 — — 6,968,333 Acquired loans Personal Banking: Residential mortgage loans 112,990 — 833 — — 113,823 Home equity loans 257,312 — 1,485 — — 258,797 Consumer loans 98,659 — 745 — — 99,404 Total Personal Banking 468,961 — 3,063 — — 472,024 Commercial Banking: Commercial real estate loans 251,761 4,838 36,915 — — 293,514 Commercial loans 49,073 3,787 6,678 — — 59,538 Total Commercial Banking 300,834 8,625 43,593 — — 353,052 Total acquired loans 769,795 8,625 46,656 — — 825,076 Total loans $ 7,452,732 102,834 237,843 — — 7,793,409
Schedule of financial instruments with off-balance-sheet risk	Financial instruments with off-balance-sheet risk as of December 31, 2018 and 2017 are presented in the following table: December 31, 2018 2017 Loan commitments $ 136,760 181,058 Undisbursed lines of credit 788,262 872,700 Standby letters of credit 32,581 25,718 Total $ 957,603 1,079,476
Schedule of changes in mortgage servicing rights	The following table shows changes in MSRs as of and for the years ended December 31, 2018 and 2017 : Servicing rights Valuation allowance Net carrying value and fair value Balance at December 31, 2016 $ 4,239 (4 ) 4,235 Additions 833 4 837 Amortization (1,549 ) — (1,549 ) Balance at December 31, 2017 3,523 — 3,523 Additions 50 — 50 Amortization (1,470 ) — (1,470 ) Balance at December 31, 2018 $ 2,103 — 2,103

Accrued Interest Receivable (Ta

Accrued Interest Receivable (Tables)	12 Months Ended
	Dec. 31, 2018
Interest Receivable and Other Assets [Abstract]
Schedule of accrued interest receivable	Accrued interest receivable as of December 31, 2018 and 2017 is presented in the following table: December 31, 2018 2017 Investment securities $ 1,035 1,260 Mortgage-backed securities 1,333 1,107 Loans receivable 22,122 20,985 $ 24,490 23,352

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2018
Property, Plant and Equipment [Abstract]
Schedule of premises and equipment	Premises and equipment at December 31, 2018 and 2017 are summarized by major classification in the following table: December 31, 2018 2017 Land and land improvements $ 21,042 21,563 Office buildings and improvements 150,328 150,056 Furniture, fixtures and equipment 119,829 125,347 Leasehold improvements 17,419 19,909 Total, at cost 308,618 316,875 Less accumulated depreciation and amortization (165,228 ) (164,931 ) Premises and equipment, net $ 143,390 151,944
Schedule of minimum annual rentals	Minimum annual rentals by fiscal year are summarized in the following table: 2019 $ 4,677 2020 3,884 2021 3,179 2022 2,465 2023 2,040 Thereafter 7,784 Total $ 24,029

Goodwill and Other Intangible_2

Goodwill and Other Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 : December 31, 2018 2017 Amortizable intangible assets: Core deposit intangibles - gross $ 63,685 63,685 Acquisitions — — Less: accumulated amortization (45,027 ) (40,029 ) Core deposit intangibles - net $ 18,658 23,656 Customer and Contract intangible assets - gross $ 10,474 10,474 Acquisitions — — Less: accumulated amortization (9,311 ) (8,461 ) Customer and Contract intangible assets - net $ 1,163 2,013
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, 2018 , 2017 and 2016 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, 2016 $ 4,259 For the year ended December 31, 2017 6,764 For the year ended 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 For the year ending December 31, 2022 2,456 For the year ending December 31, 2023 1,847
Schedule of the changes in carrying amount of goodwill	The following table provides information for the changes in the carrying amount of goodwill: Total Balance at December 31, 2016 $ 307,420 Goodwill acquired — Balance at December 31, 2017 307,420 Goodwill acquired — Balance at December 31, 2018 $ 307,420

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2018
Deposits [Abstract]
Schedule of deposit balances	Deposit balances at December 31, 2018 and 2017 are shown in the table below: December 31, 2018 2017 Savings deposits $ 1,636,099 1,653,579 Interest-bearing demand deposits 1,455,460 1,442,928 Noninterest-bearing demand deposits 1,736,156 1,610,409 Money market deposit accounts 1,661,623 1,707,450 Time deposits 1,404,841 1,412,623 Total deposits $ 7,894,179 7,826,989
Summarizes the contractual maturity of the certificate accounts	The following table summarizes the contractual maturity of time deposits at December 31, 2018 and 2017 : December 31, 2018 2017 Due within 12 months $ 553,173 666,348 Due between 12 and 24 months 352,074 226,171 Due between 24 and 36 months 213,591 201,654 Due between 36 and 48 months 171,866 131,530 Due between 48 and 60 months 108,068 174,704 After 60 months 6,069 12,216 Total time deposits $ 1,404,841 1,412,623
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, 2018 , 2017 and 2016 : Years ended December 31, 2018 2017 2016 Savings deposits $ 3,064 3,062 3,218 Interest-bearing demand deposits 3,607 1,027 462 Money market deposit accounts 5,740 4,203 3,621 Time deposits 18,574 14,765 16,164 Total interest expense $ 30,985 23,057 23,465

Borrowed Funds (Tables)

Borrowed Funds (Tables)	12 Months Ended
	Dec. 31, 2018
Debt Disclosure [Abstract]
Schedule of borrowed funds	Borrowed funds at December 31, 2018 and 2017 are presented in the following table: December 31, 2018 2017 Amount Average rate Amount Average rate Term notes payable to the FHLB of Pittsburgh: Due within one year $ 128,600 2.60 % $ — — % Total term notes payable to FHLB of Pittsburgh 128,600 — Collateralized borrowings, due within one year 105,789 0.20 % 108,238 0.20 % Total borrowed funds $ 234,389 $ 108,238
Schedule of capital debt securities and junior subordinated deferrable interest debentures	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, 2018 and 2017 : Capital debt December 31, securities 2018 2017 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

Income Taxes (Tables)

Income Taxes (Tables)	12 Months Ended
	Dec. 31, 2018
Income Tax Disclosure [Abstract]
Schedule of allocation of income tax	Total income tax was allocated for the years ended December 31, 2018 , 2017 and 2016 as follows: Years ended December 31, 2018 2017 2016 Income before income taxes $ 28,422 41,444 21,648 Shareholders’ equity for unrealized loss on securities available-for-sale (573 ) (3,403 ) (1,871 ) Shareholders’ equity for tax benefit for excess of fair value above cost of stock benefit plans — — (1,425 ) Shareholders’ equity for pension adjustment (24 ) (213 ) (2,455 ) Shareholders’ equity for swap fair value adjustment 223 585 539 Unallocated income tax $ 28,048 38,413 16,436
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, 2018 2017 2016 Current $ 31,192 30,127 18,914 Deferred (2,770 ) 11,317 2,734 Total income tax expense $ 28,422 41,444 21,648
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, 2018 , 2017 and 2016 , is as follows: Years ended December 31, 2018 2017 2016 Expected tax rate 21.0 % 35.0 % 35.0 % Tax-exempt interest income (0.9 )% (1.5 )% (3.3 )% State income tax, net of federal benefit 3.8 % 3.2 % 1.2 % Bank-owned life insurance (0.9 )% (1.6 )% (2.6 )% Stock-based compensation (0.8 )% (0.9 )% — % Dividends on stock plans (0.6 )% (1.1 )% (2.0 )% Low income housing and historic tax credits (0.6 )% (0.5 )% (1.0 )% ESOP termination — % — % 3.4 % Adjustment to net deferred tax liabilities for enacted changes in tax laws and rates — % (2.3 )% — % Other 0.2 % 0.2 % (0.3 )% Effective tax rate 21.2 % 30.5 % 30.4 %
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, 2018 and 2017 are presented below: December 31, 2018 2017 Deferred tax assets: Deferred rent $ 115 87 Deferred compensation expense 2,357 1,040 Bad debts 11,257 10,277 Other reserves 1,065 953 Accrued postretirement benefit cost 410 413 Stock benefit plans 904 744 Writedown of investment securities — 104 Accrued expenses — 35 Pension and postretirement benefits 13,057 13,033 Unrealized loss on the fair value of derivatives — 223 Unrealized loss on the fair value of securities available-for-sale 2,733 2,160 Deferred income 822 1,001 Other 219 141 Total deferred tax assets 32,939 30,211 Deferred tax liabilities: Pension expense 5,686 5,542 Purchase accounting 180 303 Intangible assets 13,839 13,546 Mortgage servicing rights 460 777 Fixed assets 4,602 4,940 Net deferred loan costs 4,558 4,690 Other 331 274 Total deferred tax liabilities 29,656 30,072 Net deferred tax asset $ 3,283 139

Earnings Per Share (Tables)

Earnings Per Share (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 , 2017 and 2016 follows: Years ended December 31, 2018 2017 2016 Net income available to common shareholders $ 105,491 94,467 49,667 Weighted average common shares outstanding 102,073,888 101,015,083 99,439,174 Dilutive potential shares due to effect of stock options 1,492,013 1,549,822 1,225,514 Total weighted average common shares and dilutive potential shares 103,565,901 102,564,905 100,664,688 Basic earnings per share (1) $ 1.03 0.94 0.50 Diluted earnings per share (1) $ 1.02 0.92 0.49 (1) Not in thousands.

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2018
Retirement Benefits [Abstract]
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 pension cost for the defined benefit pension plans for the years ended December 31, 2018 , 2017 and 2016 : Years ended December 31, 2018 2017 2016 Service cost $ 6,864 6,149 5,496 Interest cost 6,712 6,879 6,781 Expected return on plan assets (11,968 ) (10,512 ) (9,897 ) Net amortization and deferral 1,167 1,388 1,388 Net periodic pension cost $ 2,775 3,904 3,768 The following table sets forth the net periodic benefit cost for the postretirement healthcare benefits plan for the years ended December 31, 2018 , 2017 and 2016 : Years ended December 31, 2018 2017 2016 Interest cost $ 54 68 70 Amortization of net loss 98 108 90 Net period benefit cost $ 152 176 160
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, 2018 2017 2016 Net (gain)/loss $ (305 ) (156 ) 109 Total recognized in other comprehensive income $ (305 ) (156 ) 109 Total recognized in net periodic benefit cost and other comprehensive (loss)/income $ (153 ) 20 269 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, 2018 2017 2016 Net (gain)/loss $ (1,716 ) (1,647 ) 1,550 Prior service cost — — — Amortization of prior service cost 2,323 2,323 2,323 Total recognized in other comprehensive income $ 607 676 3,873 Total recognized in net periodic pension cost and other comprehensive income $ 3,382 4,580 7,641
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, 2018 and 2017 : December 31, 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 1,637 1,779 Interest cost 54 68 Actuarial loss (207 ) (48 ) Benefits paid (152 ) (162 ) Benefit obligation at end of year $ 1,332 1,637 Change in plan assets: Employer contributions 152 162 Benefits paid (152 ) (162 ) Funded status at year end $ (1,332 ) (1,637 ) The following table sets forth information for the defined benefit pension plans’ funded status at December 31, 2018 and 2017 : December 31, 2018 2017 Change in benefit obligation: Benefit obligation at beginning of year $ 193,142 172,208 Service cost 6,864 6,149 Interest cost 6,712 6,879 Actuarial (gain)/loss (19,015 ) 14,807 Benefits paid (6,582 ) (6,901 ) Benefit obligation at end of year $ 181,121 193,142 Change in plan assets: Fair value of plan assets at beginning of year $ 173,668 152,625 Actual return on plan assets (8,820 ) 23,255 Employer contributions 2,500 4,689 Benefits paid (6,582 ) (6,901 ) Fair value of plan assets at end of period $ 160,766 173,668 Funded status at end of year $ (20,355 ) (19,474 )
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, 2018 2017 2016 Discount rate 3.53 % 4.06 % 4.25 % Expected long-term rate of return on assets 7.00 % 7.00 % 7.00 % Rate of increase in compensation levels 3.00 % 3.00 % 3.00 % The assumptions used to develop the preceding information for postretirement healthcare benefits are as follows: Years ended December 31, 2018 2017 2016 Discount rate 3.53 % 4.06 % 4.25 % Monthly cost of healthcare insurance per beneficiary (1) $ 507 548 539 Annual rate of increase in healthcare costs 4.00 % 4.00 % 4.00 % (1) Not in thousands
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, 2018 2017 2016 Discount rate 4.15 % 3.53 % 4.06 % Expected long-term rate of return on assets 7.00 % 7.00 % 7.00 % 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, 2018 2017 Projected benefit obligation $ 181,121 193,142 Accumulated benefit obligation 181,121 193,142 Fair value of plan assets 160,766 173,668
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 2018 2017 Debt securities 20 – 50% 27 % 23 % Equity securities 30 – 60% 70 % 73 % Other 5 – 50% 3 % 4 % Total 100 % 100 %
Schedule of allocation of plan assets	The following table sets forth the pension plan assets as of December 31, 2018 and 2017 : December 31, 2018 2017 Mutual funds - debt $ 43,549 40,010 Mutual funds - equity 112,580 125,871 Cash and cash equivalents 4,637 7,787
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, 2018 2017 Projected benefit obligation $ 1,332 1,637 Accumulated benefit obligation 1,332 1,637
Schedule of activity under option plans	The following table summarizes the activity in our option plans during the years ended December 31, 2018 , 2017 and 2016 (amounts in this table are not in thousands): Years ended December 31, 2018 2017 2016 Number Weighted average exercise price Number Weighted average exercise price Number Weighted average exercise price Balance at beginning of year 5,695,570 $ 12.75 5,804,105 $ 12.25 6,306,496 $ 11.81 Granted (1) 895,960 16.59 819,010 15.57 725,400 14.15 Exercised (2) (830,712 ) 10.38 (630,591 ) 11.66 (1,081,072 ) 11.01 Forfeited/expired (148,006 ) 12.52 (296,954 ) 12.43 (146,719 ) 12.71 Balance at end of year 5,612,812 13.49 5,695,570 12.75 5,804,105 12.25 Exercisable at end of year 3,016,175 12.61 3,016,367 11.99 3,035,718 11.71 (1) Weighted average fair value of options at grant date: $1.49 , $1.55 and $1.52 , respectively. (2) The total intrinsic value of options exercised was $4.8 million , $3.5 million and $5.1 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, 2018 : Exercise Exercise Exercise Exercise Exercise Exercise Exercise Options outstanding: Number of options 106,041 2,250 869,718 205,326 339,197 246,618 8,500 Weighted average remaining contract life (years) 1.00 0.25 9.25 2.00 3.25 3.00 2.25 Options exercisable: Number of options 106,041 2,250 156,040 211,239 246,865 255,741 7,000 Weighted average remaining term - vested (years) 1.00 0.25 9.25 2.00 3.25 3.00 2.25 Exercise Exercise Exercise Exercise Exercise Exercise Total Options outstanding: Number of options 1,289,238 457,852 385,906 393,497 589,728 718,941 5,612,812 Weighted average remaining contract life (years) 2.25 6.25 4.25 5.25 7.25 8.25 5.36 Options exercisable: Number of options 1,023,261 194,851 245,720 207,164 191,970 168,033 3,016,175 Weighted average remaining term - vested (years) 2.25 6.25 4.25 5.25 7.25 8.25 3.97

Disclosures About Fair Value _2

Disclosures About Fair Value of Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 : December 31, 2018 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 68,789 68,789 68,789 — — Securities available-for-sale 801,450 801,450 — 801,450 — Securities held-to-maturity 22,765 22,446 — 22,446 — Loans receivable, net 7,996,225 7,845,313 — — 7,845,313 Accrued interest receivable 24,490 24,490 24,490 — — Interest rate swaps 6,445 6,445 — 6,445 — FHLB Stock 15,635 15,635 — — — Total financial assets $ 8,935,799 8,784,568 93,279 830,341 7,845,313 Financial liabilities: Savings and checking accounts $ 6,489,338 6,489,338 6,489,338 — — Time deposits 1,404,841 1,434,410 — — 1,434,410 Borrowed funds 234,389 234,389 234,389 — — Junior subordinated debentures 111,213 102,572 — — 102,572 Interest rate swaps 6,445 6,445 — 6,445 — Accrued interest payable 744 744 744 — — Total financial liabilities $ 8,246,970 8,267,898 6,724,471 6,445 1,536,982 December 31, 2017 Carrying Estimated amount fair value Level 1 Level 2 Level 3 Financial assets: Cash and cash equivalents $ 77,710 77,710 77,710 — — Securities available-for-sale 792,535 792,535 574 791,961 — Securities held-to-maturity 29,678 29,667 — 29,667 — Loans receivable, net 7,736,614 7,762,562 3,128 — 7,759,434 Accrued interest receivable 23,352 23,352 23,352 — — Interest rate swaps 214 214 — 214 — FHLB Stock 11,733 11,733 — — — Total financial assets $ 8,671,836 8,697,773 104,764 821,842 7,759,434 Financial liabilities: Savings and checking accounts $ 6,414,366 6,414,366 6,414,366 — — Time deposits 1,412,623 1,433,380 — — 1,433,380 Borrowed funds 108,238 108,238 108,238 — — Junior subordinated debentures 111,213 110,954 — — 110,954 Interest rate swaps 1,278 1,278 — 1,278 — Foreign exchange swaps 61 61 — 61 — Accrued interest payable 460 460 460 — — Total financial liabilities $ 8,048,239 8,068,737 6,523,064 1,339 1,544,334
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, 2018 : Level 1 Level 2 Level 3 Total at fair value Assets Equity securities $ — — — — Debt securities: U.S. government and agencies — 14,780 — 14,780 Government sponsored enterprises — 187,335 — 187,335 States and political subdivisions — 21,163 — 21,163 Corporate — 914 — 914 Total debt securities — 224,192 — 224,192 Residential mortgage-backed securities: GNMA — 27,041 — 27,041 FNMA — 73,196 — 73,196 FHLMC — 51,621 — 51,621 Non-agency — 528 — 528 Collateralized mortgage obligations: GNMA — 52,331 — 52,331 FNMA — 207,033 — 207,033 FHLMC — 165,508 — 165,508 Non-agency — — — — Total mortgage-backed securities — 577,258 — 577,258 Interest rate swaps — 6,445 — 6,445 Total assets $ — 807,895 — 807,895 Liabilities Interest rate swaps $ — 6,445 — 6,445 Total liabilities $ — 6,445 — 6,445 The following table represents assets and liabilities measured at fair value on a recurring basis as of December 31, 2017 : Level 1 Level 2 Level 3 Total at fair value Assets Equity securities $ 574 — — 574 Debt securities: U.S. government and agencies — 1 — 1 Government sponsored enterprises — 209,269 — 209,269 States and political subdivisions — 51,056 — 51,056 Corporate — 909 — 909 Total debt securities — 261,235 — 261,235 Residential mortgage-backed securities: GNMA — 29,695 — 29,695 FNMA — 82,969 — 82,969 FHLMC — 64,021 — 64,021 Non-agency — 555 — 555 Collateralized mortgage obligations: GNMA — 4,769 — 4,769 FNMA — 191,512 — 191,512 FHLMC — 157,190 — 157,190 SBA — — — — Non-agency — 15 — 15 Total mortgage-backed securities — 530,726 — 530,726 Interest rate swaps — 214 — 214 Total assets $ 574 792,175 — 792,749 Liabilities Interest rate swaps $ — 1,278 — 1,278 Foreign exchange swaps — 61 — 61 Total liabilities $ — 1,339 — 1,339
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, 2018 and 2017 : December 31, 2018 2017 Debt securities Beginning balance January 1, $ — 9,366 Total net realized investment gains and net change in unrealized appreciation: Included in net income as OTTI — — Included in other comprehensive income — 1,282 Purchases — — Sales (10,648 ) Transfers into Level 3 — — Transfers out of Level 3 — — Ending balance December 31, $ — —
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, 2018 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 40,333 40,333 Real estate owned — — 2,498 2,498 Total assets $ — — 42,831 42,831 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, 2017 : Level 1 Level 2 Level 3 Total assets at fair value Loans evaluated for impairment $ — — 33,421 33,421 Real estate owned — — 5,666 5,666 Total assets $ — — 39,087 39,087
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, 2018 : Fair value Valuation techniques Significant unobservable inputs Range (weighted average) Loans measured for impairment $ 40,333 Appraisal Estimated costs to sell 10% value (1) Discounted cash Discount rate 4.25% to 10.0% (7.50%) flow Real estate owned 2,498 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 Requiremen_2

Regulatory Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2018
Regulatory Capital Requirements [Abstract]
Schedule of actual, required, and well capitalized levels	The actual, required, and well capitalized levels as of December 31, 2018 and 2017 were as follows: At December 31, 2018 Minimum capital Well capitalized Actual requirements (1) requirements Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,183,619 15.833 % $ 738,212 9.875 % $ 747,557 10.000 % Northwest Bank 1,026,027 13.736 % 737,647 9.875 % 746,984 10.000 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,128,405 15.095 % 588,701 7.875 % 598,045 8.000 % Northwest Bank 970,813 12.996 % 588,250 7.875 % 597,587 8.000 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,020,530 13.652 % 476,567 6.375 % 485,912 6.500 % Northwest Bank 970,813 12.996 % 476,202 6.375 % 448,190 6.000 % Tier 1 capital (leverage) (to average assets) Northwest Bancshares, Inc. 1,128,405 11.899 % 379,342 4.000 % 474,177 5.000 % Northwest Bank 970,813 10.240 % 379,236 4.000 % 474,045 5.000 % (1) Amounts and ratios include the 2018 capital conservation buffer of 1.875% with the exception of Tier 1 capital to average assets. For further information related to the capital conservation buffer, see Item 1. Business - "Supervision and Regulation". At December 31, 2017 Minimum capital Well capitalized Actual requirements (1) requirements Amount Ratio Amount Ratio Amount Ratio Total capital (to risk weighted assets) Northwest Bancshares, Inc. $ 1,136,076 15.831 % $ 663,823 9.250 % $ 71,747 10.000 % Northwest Bank 1,017,251 14.189 % 663,179 9.250 % 716,951 10.000 % Tier 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 1,079,270 15.039 % 520,294 7.250 % 574,117 8.000 % Northwest Bank 960,443 13.396 % 519,789 7.250 % 573,560 8.000 % CET 1 capital (to risk weighted assets) Northwest Bancshares, Inc. 971,395 13.536 % 412,647 5.750 % 466,470 6.500 % Northwest Bank 960,443 13.396 % 412,247 5.750 % 430,170 6.000 % Tier I capital (leverage) (to average assets) Northwest Bancshares, Inc. 1,079,270 11.676 % 369,735 4.000 % 462,169 5.000 % Northwest Bank 960,443 10.400 % 369,482 4.000 % 461,853 5.000 % (1) Amounts and ratios include the 2017 capital conservation buffer of 1.250% with the exception of Tier 1 capital to average assets. For further information related to the capital conservation buffer, see Item 1. Business - "Supervision and Regulation".

Components of Accumulated Oth_2

Components of Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2018
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, 2018 and 2017 : December 31, 2018 2017 Unrealized gain on marketable securities available-for-sale $ (6,832 ) (4,409 ) Fair value of interest rate swaps — (691 ) Defined benefit pension plans (32,864 ) (26,980 ) Accumulated other comprehensive income $ (39,696 ) (32,080 )
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, 2018 : 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, $ (4,409 ) (691 ) (26,980 ) (32,080 ) Reclassification due to adoption of ASU No. 2018-02 (991 ) (149 ) (5,606 ) (6,746 ) Other comprehensive income/(loss) before reclassification adjustments (1,277 ) 840 (1,181 ) (1,618 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (155 ) — 903 748 Net other comprehensive income/(loss) (2,423 ) 691 (5,884 ) (7,616 ) Balance as of December 31, $ (6,832 ) — (32,864 ) (39,696 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $215 , net of tax (income tax expense) of $60 . (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 $(3,568) , net of tax (income tax expense) of $361 . The following table shows the changes in accumulated other comprehensive income by component for the year ended December 31, 2017 : 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, $ 395 (1,778 ) (26,608 ) (27,991 ) Other comprehensive income/(loss) before reclassification adjustments (2,478 ) 1,087 (1,254 ) (2,645 ) Amounts reclassified from accumulated other comprehensive income (1), (2) (2,326 ) — 882 (1,444 ) Net other comprehensive income/(loss) (4,804 ) 1,087 (372 ) (4,089 ) Balance as of December 31, $ (4,409 ) (691 ) (26,980 ) (32,080 ) (1) Consists of realized gains on securities (gain on sales of investments, net) of $3,814 net of tax (income tax expense) of $1,488 . (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 $(3,818) , net of tax (income tax expense) of $613 . 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 losses 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 .

Parent Company Only Financial_2

Parent Company Only Financial Statements - Condensed (Tables)	12 Months Ended
	Dec. 31, 2018
Condensed Financial Information Disclosure [Abstract]
Schedule of statements of financial condition	December 31, 2018 2017 Assets Cash and cash equivalents $ 155,524 26,088 Marketable securities available-for-sale — 545 Investment in bank subsidiary 1,211,258 1,200,799 Other assets 2,298 92,712 Total assets $ 1,369,080 1,320,144 Liabilities and Shareholders’ Equity Liabilities: Debentures payable $ 111,213 111,213 Other liabilities 230 1,207 Total liabilities 111,443 112,420 Shareholders’ equity 1,257,637 1,207,724 Total liabilities and shareholders’ equity $ 1,369,080 1,320,144
Schedule of statements of income	Years ended December 31, 2018 2017 2016 Income: Interest income $ 198 137 737 Other income 752 2,297 709 Dividends from bank subsidiary 105,000 90,000 50,000 Undistributed earnings from equity investment in bank subsidiary 5,149 7,255 2,760 Total income 111,099 99,689 54,206 Expense: Compensation and benefits 1,225 1,282 1,129 Other expense 660 553 561 Interest expense 4,961 4,666 4,560 Total expense 6,846 6,501 6,250 Income before income taxes 104,253 93,188 47,956 Federal and state income taxes (1,238 ) (1,279 ) (1,711 ) Net income $ 105,491 94,467 49,667
Schedule of statements of cash flows	Years ended December 31, 2018 2017 2016 Operating activities: Net income $ 105,491 94,467 49,667 Adjustments to reconcile net income to net cash provided by operating activities: Undistributed earnings of subsidiary (5,149 ) (7,255 ) (2,760 ) Noncash stock benefit plan compensation expense — 4,894 10,916 Gain on sale of marketable securities (146 ) (1,615 ) (43 ) Net change in other assets and liabilities 91,520 (43,513 ) (63,533 ) Net cash provided by/(used in) operating activities 191,716 46,978 (5,753 ) Investing activities: Net (Purchase)/sale of marketable securities (550 ) 2,800 (1,952 ) Net cash provided by/(used in) investing activities (550 ) 2,800 (1,952 ) Financing activities: Cash dividends paid (69,921 ) (65,212 ) (60,156 ) Share repurchases — — (1,752 ) Repayment of loan to ESOP — — 797 Excess tax benefit from stock-based compensation — — 1,425 Proceeds from options exercised 8,191 7,001 10,856 Net cash used in financing activities (61,730 ) (58,211 ) (48,830 ) Net increase/(decrease) in cash and cash equivalents $ 129,436 (8,433 ) (56,535 ) Cash and cash equivalents at beginning of year $ 26,088 34,521 91,056 Net increase/(decrease) in cash and cash equivalents 129,436 (8,433 ) (56,535 ) Cash and cash equivalents at end of year $ 155,524 26,088 34,521

Derivative Financial Instrume_2

Derivative Financial Instruments (Tables)	12 Months Ended
	Dec. 31, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments	The following table presents information regarding our derivative financial instruments, at December 31, : Asset derivatives Liability derivatives Notional amount Fair value Notional amount Fair value 2018: Derivatives designated as hedging instruments: Interest rate swap agreements $ — — — — Derivatives not designated as hedging instruments: Interest rate swap agreements 221,919 6,445 221,919 6,445 Foreign exchange swap agreements — — — — Total derivatives $ 221,919 6,445 221,919 6,445 2017: Derivatives designated as hedging instruments: Interest rate swap agreements $ — — 50,000 1,064 Derivatives not designated as hedging instruments: Interest rate swap agreements 92,631 214 92,631 214 Foreign exchange swap agreements — — 12,344 61 Total derivatives $ 92,631 214 154,975 1,339
Gain (Loss) on Derivative Instruments	The following table indicates the gain or loss recognized in income on derivatives for the periods indicated: For the years ended December 31, 2018 2017 2016 Non-hedging swap derivatives: Increase/(decrease) in other income $ (288 ) (373 ) — Hedging interest rate derivatives: Increase in interest expense 949 1,599 1,866

Selected Quarterly Financial _2

Selected Quarterly Financial Data - Unaudited (Tables)	12 Months Ended
	Dec. 31, 2018
Quarterly Financial Information Disclosure [Abstract]
Schedule of selected quarterly financial data	Quarters ended March 31, June 30, September 30, December 31, (In thousands, except per share data) 2018: Interest income $ 89,533 92,875 95,605 97,768 Interest expense 7,766 8,649 9,788 10,937 Net interest income 81,767 84,226 85,817 86,831 Provision for loan losses 4,209 5,349 6,982 3,792 Noninterest income 21,788 24,109 22,557 23,248 Noninterest expenses 67,421 69,787 66,617 72,273 Income before income taxes 31,925 33,199 34,775 34,014 Income tax expense 6,940 6,900 7,035 7,547 Net income $ 24,985 26,299 27,740 26,467 Basic earnings per share $ 0.25 0.26 0.27 0.26 Diluted earnings per share $ 0.24 0.25 0.27 0.26 Quarters ended March 31, June 30, September 30, December 31, (In thousands, except per share data) 2017: Interest income $ 87,267 89,797 90,231 91,561 Interest expense 6,690 7,066 6,994 7,321 Net interest income 80,577 82,731 83,237 84,240 Provision for loan losses 4,637 5,562 3,027 6,525 Noninterest income 21,504 41,477 24,594 22,905 Noninterest expenses 71,646 73,262 68,799 71,896 Income before income taxes 25,798 45,384 36,005 28,724 Income tax expense 8,052 14,402 12,414 6,576 Net income $ 17,746 30,982 23,591 22,148 Basic earnings per share $ 0.18 0.31 0.23 0.22 Diluted earnings per share $ 0.17 0.30 0.23 0.22 Quarters ended March 31, June 30, September 30, 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

Summary of Significant Accoun_3

Summary of Significant Accounting Policies - Loans Receivable and Allowance for Loan Losses and Other Narrative Information (Details)	12 Months Ended
	Dec. 31, 2018USD ($)bank	Dec. 31, 2017USD ($)
Nature of Operations
Number of banking locations | bank	172
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
Residential mortgage loans classified as held-for-sale	$ 0	$ 3,100,000
Allowance for Loan Losses and Provision for Loan Losses
Number of days for loans not deemed to be impaired	30 days
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 Accoun_4

Summary of Significant Accounting Policies - Premises and Equipment and Goodwill (Details)	12 Months Ended
	Dec. 31, 2018
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 Accoun_5

Summary of Significant Accounting Policies - Stock Related Compensation and Segments (Details) $ in Millions	May 14, 2018shares	May 17, 2017shares	May 18, 2016shares	Dec. 31, 2018USD ($)segmentshares	Dec. 31, 2017USD ($)shares	Dec. 31, 2016USD ($)shares
Segment Reporting
Number of reportable segments | segment				1
Stock options
Stock Related Compensation
Expected volatility, minimum (as a percent)				14.00%
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%
Number of shares awarded				895,960	819,010	725,400
Vesting period				7 years	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				3 years 11 months 18 days
Stock options | Minimum
Stock Related Compensation
Dividend yields (as a percent)				3.20%
Expected lives				7 years
Stock options | Maximum
Stock Related Compensation
Dividend yields (as a percent)				5.10%
Expected lives				9 years
Stock options | Employees
Stock Related Compensation
Number of shares awarded	831,160	754,210	660,600	831,160	754,210
Stock options | Director
Stock Related Compensation
Number of shares awarded	64,800	64,800	64,800	64,800	64,800
Restricted common shares
Stock Related Compensation
Vesting period				7 years	10 years
Stock-based aggregate disclosure
Stock-based employee compensation expense | $				$ 5.8	$ 3.8	$ 3.5
Effect of compensation expense on net income included in income before income taxes | $				$ 4.2	$ 2.3	$ 2.2
Restricted common shares | Employees
Stock Related Compensation
Number of shares awarded	390,030	378,050	310,160	390,030	353,750
Restricted common shares | Director
Stock Related Compensation
Number of shares awarded	24,300	24,300	24,300	24,300	24,300

Recent Accounting Pronounceme_2

Recent Accounting Pronouncements - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Jan. 01, 2019
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Reclassification due to adoption of ASU No. 2018-02	$ 6,746
Accounting Standards Update 2017-07
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net periodic benefit cost		$ 2,100	$ 1,600
Subsequent Event | Minimum | Scenario, Forecast | Accounting Standards Update 2016-02
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Lease liability				$ 40,000
Right-of-use asset				40,000
Subsequent Event | Maximum | Scenario, Forecast | Accounting Standards Update 2016-02
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Lease liability				45,000
Right-of-use asset				$ 45,000

Marketable Securities - Availab

Marketable Securities - Available For Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized cost
Marketable securities available-for-sale, amortized cost	$ 811,015	$ 800,094
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	2,958	3,453
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(12,523)	(11,012)
Fair value
Marketable securities available-for-sale, total fair value	801,450	792,535
U.S. Government and agencies
Amortized cost
Due in one year or less		1
Due in one year through five years	14,756
Gross unrealized holding gains
Due in one year or less		0
Due in one year through five years	24
Gross unrealized holding losses
Due in one year or less		0
Due in one year through five years	0
Fair value
Due in one year or less		1
Due in one year through five years	14,780
Government sponsored enterprises
Amortized cost
Due in one year or less	85,089	66,566
Due in one year through five years	101,078	140,624
Due after five years through ten years		0
Due after ten years	3,546	4,833
Gross unrealized holding gains
Due in one year or less	0	14
Due in one year through five years	71	0
Due after five years through ten years		0
Due after ten years	0	0
Gross unrealized holding losses
Due in one year or less	(795)	(289)
Due in one year through five years	(1,512)	(2,402)
Due after five years through ten years		0
Due after ten years	(142)	(77)
Fair value
Due in one year or less	84,294	66,291
Due in one year through five years	99,637	138,222
Due after five years through ten years		0
Due after ten years	3,404	4,756
Equity securities
Amortized cost
Equity securities		551
Gross unrealized holding gains
Equity securities		29
Gross unrealized holding losses
Equity securities		(6)
Fair value
Equity securities		574
Municipal securities
Amortized cost
Due in one year or less	1,333	2,492
Due in one year through five years	3,985	7,072
Due after five years through ten years	10,603	14,576
Due after ten years	5,105	26,371
Gross unrealized holding gains
Due in one year or less	2	7
Due in one year through five years	54	82
Due after five years through ten years	60	171
Due after ten years	31	292
Gross unrealized holding losses
Due in one year or less	(6)	(1)
Due in one year through five years	(4)	(6)
Due after five years through ten years	0	0
Due after ten years	0	0
Fair value
Due in one year or less	1,329	2,498
Due in one year through five years	4,035	7,148
Due after five years through ten years	10,663	14,747
Due after ten years	5,136	26,663
Corporate debt issues
Amortized cost
Due after five years through ten years	914
Due after ten years		909
Gross unrealized holding gains
Due after five years through ten years	0
Due after ten years		0
Gross unrealized holding losses
Due after five years through ten years	0
Due after ten years		0
Fair value
Due after five years through ten years	914
Due after ten years		909
Fixed rate | Pass-through
Amortized cost
Marketable securities available-for-sale, amortized cost	130,172	144,411
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	568	1,108
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(4,113)	(2,817)
Fair value
Marketable securities available-for-sale, total fair value	126,627	142,702
Fixed rate | Non-agency CMOs
Amortized cost
Marketable securities available-for-sale, amortized cost		15
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains		0
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses		0
Fair value
Marketable securities available-for-sale, total fair value		15
Fixed rate | Agency CMOs
Amortized cost
Marketable securities available-for-sale, amortized cost	365,427	284,320
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	865	37
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(5,921)	(5,271)
Fair value
Marketable securities available-for-sale, total fair value	360,371	279,086
Variable rate | Pass-through
Amortized cost
Marketable securities available-for-sale, amortized cost	24,761	33,079
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	1,003	1,464
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(5)	(6)
Fair value
Marketable securities available-for-sale, total fair value	25,759	34,537
Variable rate | Agency CMOs
Amortized cost
Marketable securities available-for-sale, amortized cost	64,246	74,274
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	280	249
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(25)	(137)
Fair value
Marketable securities available-for-sale, total fair value	64,501	74,386
Residential mortgage-backed securities
Amortized cost
Marketable securities available-for-sale, amortized cost	584,606	536,099
Gross unrealized holding gains
Marketable securities available-for-sale, gross unrealized holding gains	2,716	2,858
Gross unrealized holding losses
Marketable securities available-for-sale, gross unrealized holding losses	(10,064)	(8,231)
Fair value
Marketable securities available-for-sale, total fair value	$ 577,258	$ 530,726

Marketable Securities - Held To

Marketable Securities - Held To Maturity (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Amortized cost
Held-to-maturity securities, amortized cost	$ 22,765	$ 29,678
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	103	237
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	(422)	(248)
Fair value
Held-to-maturity securities, fair value	22,446	29,667
Residential mortgage-backed securities
Amortized cost
Held-to-maturity securities, amortized cost	22,765	29,678
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	103	237
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	(422)	(248)
Fair value
Held-to-maturity securities, fair value	22,446	29,667
Fixed rate | Pass-through
Amortized cost
Held-to-maturity securities, amortized cost	2,896	3,760
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	53	140
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	2,949	3,900
Fixed rate | Agency CMOs
Amortized cost
Held-to-maturity securities, amortized cost	17,552	22,906
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	0	20
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	(422)	(248)
Fair value
Held-to-maturity securities, fair value	17,130	22,678
Variable rate | Pass-through
Amortized cost
Held-to-maturity securities, amortized cost	1,666	2,283
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	39	64
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	1,705	2,347
Variable rate | Agency CMOs
Amortized cost
Held-to-maturity securities, amortized cost	651	729
Gross unrealized holding gains
Held-to-maturity securities, gross unrealized holding gains	11	13
Gross unrealized holding losses
Held-to-maturity securities, gross unrealized holding losses	0	0
Fair value
Held-to-maturity securities, fair value	$ 662	$ 742

Marketable Securities - Issuers

Marketable Securities - Issuers and the Carrying Values of Mortgage-Backed Securities (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Marketable securities
Total residential mortgage-backed securities	$ 824,200,000
Carrying value of marketable securities pledged	132,400,000
Proceeds from sale of marketable securities available-for-sale	5,206,000	$ 36,811,000	$ 1,951,000
Realized gains	189,000	1,800,000	268,000
Realized losses	37,000	626,000
Other-than-temporary impairment	0	0	$ 0
Residential mortgage-backed securities
Marketable securities
Total residential mortgage-backed securities	600,023,000	560,404,000
Residential mortgage-backed securities | FNMA
Marketable securities
Total residential mortgage-backed securities	288,825,000	286,031,000
Residential mortgage-backed securities | GNMA
Marketable securities
Total residential mortgage-backed securities	81,444,000	37,796,000
Residential mortgage-backed securities | FHLMC
Marketable securities
Total residential mortgage-backed securities	229,226,000	236,007,000
Residential mortgage-backed securities | Other (including non-agency)
Marketable securities
Total residential mortgage-backed securities	$ 528,000	$ 570,000

Marketable Securities - Fair Va

Marketable Securities - Fair Value and Gross Unrealized Losses on Investment Securities (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)investment	Dec. 31, 2017USD ($)
Marketable securities
Less than 12 months - Fair value	$ 34,960	$ 249,272
Less than 12 months - Unrealized loss	(31)	(2,536)
12 months or more - Fair value	484,809	400,583
12 months or more - Unrealized loss	(12,915)	(8,724)
Total - Fair value	519,769	649,855
Total - Unrealized loss	$ (12,946)	(11,260)
Number of investments that are temporarily impaired | investment	180
Total residential mortgage-backed securities	$ 824,200
Government sponsored enterprises
Marketable securities
Less than 12 months - Fair value	0	5,006
Less than 12 months - Unrealized loss	0	(7)
12 months or more - Fair value	136,425	197,695
12 months or more - Unrealized loss	(2,449)	(2,761)
Total - Fair value	136,425	202,701
Total - Unrealized loss	(2,449)	(2,768)
Equity securities
Marketable securities
Less than 12 months - Fair value		0
Less than 12 months - Unrealized loss		0
12 months or more - Fair value		544
12 months or more - Unrealized loss		(6)
Total - Fair value		544
Total - Unrealized loss		(6)
Municipal securities
Marketable securities
Less than 12 months - Fair value	929	4,563
Less than 12 months - Unrealized loss	(1)	(7)
12 months or more - Fair value	1,709	0
12 months or more - Unrealized loss	(10)	0
Total - Fair value	2,638	4,563
Total - Unrealized loss	(11)	(7)
Residential mortgage-backed securities - agency
Marketable securities
Total residential mortgage-backed securities	600,023	560,404
Residential mortgage-backed securities - agency | Agency CMOs
Marketable securities
Less than 12 months - Fair value	34,031	239,703
Less than 12 months - Unrealized loss	(30)	(2,522)
12 months or more - Fair value	346,675	202,344
12 months or more - Unrealized loss	(10,456)	(5,957)
Total - Fair value	380,706	442,047
Total - Unrealized loss	$ (10,486)	$ (8,479)

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, 2018	Dec. 31, 2017
Cumulative roll forward of credit related impairment losses recognized in earnings for debt securities held and not intended to be sold:
Beginning balance	$ 352	$ 7,942
Credit losses on debt securities for which other-than-temporary impairment was not previously recognized	0	0
Credit losses on debt securities for which other-than-temporary impairment was previously recognized	0	(7,265)
Reduction for securities sold realized during the year	(352)	(325)
Additional credit losses on debt securities for which other-than-temporary impairment was previously recognized	0	0
Ending balance	$ 0	$ 352

Loans Receivable and Allowanc_3

Loans Receivable and Allowance for Loan Losses - Summary of Originated and Acquired Loans (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	$ 8,257,652,000	$ 7,972,735,000
Deferred loan costs	37,618,000	27,782,000
Allowance for loan losses	(55,214,000)	(56,795,000)	$ (60,939,000)	$ (62,672,000)
Total loans receivable, net	7,996,225,000	7,736,614,000
Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(11,513,000)	(10,067,000)
Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(167,553,000)	(144,614,000)
Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(64,765,000)	(52,427,000)
Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	4,956,500,000	4,740,232,000
Allowance for loan losses		(20,339,000)	(16,116,000)
Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,860,212,000	2,772,549,000
Allowance for loan losses		(3,824,000)	(4,656,000)
Loans held-for-sale	0	3,100,000
Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	1,258,422,000	1,310,355,000
Allowance for loan losses		(4,072,000)	(3,486,000)
Personal Banking | Consumer Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	3,817,000	18,619,000
Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	834,049,000	638,709,000
Allowance for loan losses		(8,475,000)	(4,529,000)
Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	3,301,152,000	3,232,503,000
Allowance for loan losses		(30,233,000)	(39,177,000)
Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,639,374,000	2,599,340,000
Allowance for loan losses		(19,911,000)	(23,667,000)
Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	661,778,000	633,163,000
Allowance for loan losses		(10,322,000)	(15,510,000)
Originated
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	7,618,512,000	7,145,255,000
Deferred loan costs	36,820,000	26,255,000
Allowance for loan losses	(51,751,000)	(50,572,000)	(55,293,000)	(60,970,000)
Total loans receivable, net	7,361,434,000	6,917,761,000
Originated | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(11,513,000)	(10,067,000)
Originated | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(167,029,000)	(141,967,000)
Originated | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(63,605,000)	(51,143,000)
Originated | Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	4,589,503,000	4,269,735,000
Allowance for loan losses	(18,318,000)	(20,339,000)	(16,116,000)	(16,121,000)
Originated | Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,766,430,000	2,658,726,000
Allowance for loan losses	(4,054,000)	(3,824,000)	(4,656,000)	(4,692,000)
Originated | Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	1,043,878,000	1,051,558,000
Allowance for loan losses	(3,184,000)	(4,072,000)	(3,486,000)	(3,941,000)
Originated | Personal Banking | Consumer Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	3,817,000	18,619,000
Originated | Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	775,378,000	540,832,000
Allowance for loan losses	(10,404,000)	(8,475,000)	(4,529,000)	(4,213,000)
Originated | Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	3,029,009,000	2,875,520,000
Allowance for loan losses	(33,433,000)	(30,233,000)	(39,177,000)	(44,849,000)
Originated | Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	2,416,047,000	2,303,179,000
Allowance for loan losses	(26,379,000)	(19,911,000)	(23,667,000)	(32,348,000)
Originated | Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	612,962,000	572,341,000
Allowance for loan losses	(7,054,000)	(10,322,000)	(15,510,000)	(12,501,000)
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	639,140,000	827,480,000
Deferred loan costs	798,000	1,527,000
Allowance for loan losses	(3,463,000)	(6,223,000)	(5,646,000)	(1,702,000)
Total loans receivable, net	634,791,000	818,853,000
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	(524,000)	(2,647,000)
Acquired | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Undisbursed loan proceeds	(1,160,000)	(1,284,000)
Acquired | Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	366,997,000	470,497,000
Allowance for loan losses	(850,000)	(1,783,000)	(1,771,000)	(229,000)
Acquired | Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	93,782,000	113,823,000
Allowance for loan losses	(83,000)	(131,000)	(71,000)	(18,000)
Acquired | Personal Banking | Home equity loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	214,544,000	258,797,000
Allowance for loan losses	(348,000)	(762,000)	(1,047,000)	(101,000)
Acquired | Personal Banking | Consumer Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	0	0
Acquired | Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	58,671,000	97,877,000
Allowance for loan losses	(419,000)	(890,000)	(653,000)	(110,000)
Acquired | Commercial Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	272,143,000	356,983,000
Allowance for loan losses	(2,613,000)	(4,440,000)	(3,875,000)	(1,473,000)
Acquired | Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	223,327,000	296,161,000
Allowance for loan losses	(1,996,000)	(3,549,000)	(3,008,000)	(1,439,000)
Acquired | Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total loans receivable, gross	48,816,000	60,822,000
Allowance for loan losses	$ (617,000)	$ (891,000)	$ (867,000)	$ (34,000)

Loans Receivable and Allowanc_4

Loans Receivable and Allowance for Loan Losses - Narrative (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Serviced loans for others	$ 794.2	$ 887.3	$ 918.9
Percentage of loan portfolio secured by properties located in Pennsylvania	58.00%	60.00%
Adjustable rate loans	$ 2,810	$ 2,856
Fixed rate loans	$ 5,448	$ 5,117

Loans Receivable and Allowanc_5

Loans Receivable and Allowance for Loan Losses - Outstanding Principal Balance and Related Carrying Value of Acquired Loans (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Acquired
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding principal balance	$ 645,359	$ 833,940
Carrying value	638,254	825,076
Acquired loans evaluated individually for future credit losses
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding principal balance	8,189	9,735
Carrying value	5,690	6,875
Acquired loans evaluated collectively for future credit losses
Accounts, Notes, Loans and Financing Receivable [Line Items]
Outstanding principal balance	637,170	824,205
Carrying value	$ 632,564	$ 818,201

Loans Receivable and Allowanc_6

Loans Receivable and Allowance for Loan Losses - Changes in the Accretable Discount (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Receivables [Abstract]
Beginning balance	$ 1,540	$ 2,187
Accretion	(785)	(1,318)
Net reclassification from nonaccretable yield	0	671
Ending balance	$ 755	$ 1,540

Loans Receivable and Allowanc_7

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	$ 98,283	$ 84,625	$ 108,061
Average recorded investment in impaired loans	84,338	97,193	118,675
Interest income/ accretion recognized	3,762	3,982	5,596
Acquired loans evaluated individually for future credit losses
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	5,690	6,875
Outstanding principal balance	8,189	9,735
Related impairment reserve	18	88
Average recorded investment in impaired loans	6,940	9,770
Interest income/ accretion recognized	785	1,318
Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	35,723	36,833	38,606
Average recorded investment in impaired loans	33,824	35,102	37,420
Interest income/ accretion recognized	1,656	1,552	1,741
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	2,027	2,384
Outstanding principal balance	3,633	4,259
Related impairment reserve	17	49
Average recorded investment in impaired loans	2,830	2,601
Interest income/ accretion recognized	418	389
Personal Banking | Residential mortgage loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	22,508	21,605	24,193
Average recorded investment in impaired loans	20,733	21,531	24,483
Interest income/ accretion recognized	910	892	1,079
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	990	1,182
Outstanding principal balance	1,598	1,880
Related impairment reserve	6	24
Average recorded investment in impaired loans	1,294	1,251
Interest income/ accretion recognized	226	181
Personal Banking | Home equity loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	8,893	10,356	9,304
Average recorded investment in impaired loans	9,075	9,150	9,234
Interest income/ accretion recognized	511	452	496
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	1,008	1,143
Outstanding principal balance	1,959	2,219
Related impairment reserve	7	21
Average recorded investment in impaired loans	1,483	1,253
Interest income/ accretion recognized	157	157
Personal Banking | Consumer loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	4,300	4,673	4,366
Average recorded investment in impaired loans	3,992	4,042	2,931
Interest income/ accretion recognized	235	188	131
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	29	59
Outstanding principal balance	76	160
Related impairment reserve	4	4
Average recorded investment in impaired loans	53	97
Interest income/ accretion recognized	35	51
Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	62,560	47,792	69,455
Average recorded investment in impaired loans	50,514	62,091	81,255
Interest income/ accretion recognized	2,106	2,430	3,855
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	3,663	4,491
Outstanding principal balance	4,556	5,476
Related impairment reserve	1	39
Average recorded investment in impaired loans	4,110	7,169
Interest income/ accretion recognized	367	929
Commercial Banking | Commercial real estate loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	49,919	37,027	53,928
Average recorded investment in impaired loans	41,328	49,981	64,350
Interest income/ accretion recognized	1,599	1,758	2,864
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	3,584	4,388
Outstanding principal balance	4,471	5,363
Related impairment reserve	1	39
Average recorded investment in impaired loans	4,028	6,992
Interest income/ accretion recognized	358	914
Commercial Banking | Commercial loans
Composition of impaired loans by portfolio segment and by class of financing receivable
Carrying value	12,641	10,765	15,527
Average recorded investment in impaired loans	9,186	12,110	16,905
Interest income/ accretion recognized	507	672	$ 991
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	79	103
Outstanding principal balance	85	113
Related impairment reserve	0	0
Average recorded investment in impaired loans	82	177
Interest income/ accretion recognized	$ 9	$ 15

Loans Receivable and Allowanc_8

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				$ 56,795				$ 60,939				$ 62,672	$ 56,795	$ 60,939	$ 62,672
Provision	$ 3,792	$ 6,982	$ 5,349	4,209	$ 6,525	$ 3,027	$ 5,562	4,637	$ 2,145	$ 5,538	$ 4,199	1,660	20,332	19,751	13,542
Charge-offs													(29,641)	(31,254)	(24,881)
Recoveries													7,728	7,359	9,606
Balance at the end of the period	55,214				56,795				60,939				55,214	56,795	60,939
Personal Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				20,339				16,116					20,339	16,116
Provision														23,129
Charge-offs														(21,411)
Recoveries														2,505
Balance at the end of the period					20,339				16,116					20,339	16,116
Personal Banking | Residential mortgage loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,824				4,656					3,824	4,656
Provision														(390)
Charge-offs														(834)
Recoveries														392
Balance at the end of the period					3,824				4,656					3,824	4,656
Personal Banking | Home equity loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				4,072				3,486					4,072	3,486
Provision														1,474
Charge-offs														(1,080)
Recoveries														192
Balance at the end of the period					4,072				3,486					4,072	3,486
Personal Banking | Consumer Finance Loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,968				3,445					3,968	3,445
Provision														8,444
Charge-offs														(8,369)
Recoveries														448
Balance at the end of the period					3,968				3,445					3,968	3,445
Personal Banking | Consumer loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				8,475				4,529					8,475	4,529
Provision														13,601
Charge-offs														(11,128)
Recoveries														1,473
Balance at the end of the period					8,475				4,529					8,475	4,529
Commercial Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				30,233				39,177					30,233	39,177
Provision														(8,440)
Charge-offs														(3,806)
Recoveries														3,302
Balance at the end of the period					30,233				39,177					30,233	39,177
Commercial Banking | Commercial real estate loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				19,911				23,667					19,911	23,667
Provision														(3,663)
Charge-offs														(1,344)
Recoveries														1,251
Balance at the end of the period					19,911				23,667					19,911	23,667
Commercial Banking | Commercial loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				10,322				15,510					10,322	15,510
Provision														(4,777)
Charge-offs														(2,462)
Recoveries														2,051
Balance at the end of the period					10,322				15,510					10,322	15,510
Originated
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				50,572				55,293				60,970	50,572	55,293	60,970
Provision													20,939	14,689	7,266
Charge-offs													(26,695)	(25,217)	(21,111)
Recoveries													6,935	5,807	8,168
Balance at the end of the period	51,751				50,572				55,293				51,751	50,572	55,293
Originated | Personal Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				20,339				16,116				16,121	20,339	16,116	16,121
Provision													11,652		12,251
Charge-offs													(17,924)		(14,543)
Recoveries													4,251		2,287
Balance at the end of the period	18,318				20,339				16,116				18,318	20,339	16,116
Originated | Personal Banking | Residential mortgage loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,824				4,656				4,692	3,824	4,656	4,692
Provision													808		2,906
Charge-offs													(1,067)		(3,228)
Recoveries													489		286
Balance at the end of the period	4,054				3,824				4,656				4,054	3,824	4,656
Originated | Personal Banking | Home equity loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				4,072				3,486				3,941	4,072	3,486	3,941
Provision													(25)		293
Charge-offs													(1,183)		(1,090)
Recoveries													320		342
Balance at the end of the period	3,184				4,072				3,486				3,184	4,072	3,486
Originated | Personal Banking | Consumer Finance Loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,968				3,445				3,275	3,968	3,445	3,275
Provision													(1,282)		3,117
Charge-offs													(2,813)		(3,323)
Recoveries													803		376
Balance at the end of the period	676				3,968				3,445				676	3,968	3,445
Originated | Personal Banking | Consumer loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				8,475				4,529				4,213	8,475	4,529	4,213
Provision													12,151		5,935
Charge-offs													(12,861)		(6,902)
Recoveries													2,639		1,283
Balance at the end of the period	10,404				8,475				4,529				10,404	8,475	4,529
Originated | Commercial Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				30,233				39,177				44,849	30,233	39,177	44,849
Provision													9,287		(4,985)
Charge-offs													(8,771)		(6,568)
Recoveries													2,684		5,881
Balance at the end of the period	33,433				30,233				39,177				33,433	30,233	39,177
Originated | Commercial Banking | Commercial real estate loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				19,911				23,667				32,348	19,911	23,667	32,348
Provision													11,349		(9,819)
Charge-offs													(6,096)		(2,403)
Recoveries													1,215		3,541
Balance at the end of the period	26,379				19,911				23,667				26,379	19,911	23,667
Originated | Commercial Banking | Commercial loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				10,322				15,510				12,501	10,322	15,510	12,501
Provision													(2,062)		4,834
Charge-offs													(2,675)		(4,165)
Recoveries													1,469		2,340
Balance at the end of the period	7,054				10,322				15,510				7,054	10,322	15,510
Acquired
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				6,223				5,646				1,702	6,223	5,646	1,702
Provision													(607)	5,062	6,276
Charge-offs													(2,946)	(6,037)	(3,770)
Recoveries													793	1,552	1,438
Balance at the end of the period	3,463				6,223				5,646				3,463	6,223	5,646
Acquired | Personal Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				1,783				1,771				229	1,783	1,771	229
Provision													(419)	1,453	3,283
Charge-offs													(1,005)	(2,179)	(2,381)
Recoveries													491	738	640
Balance at the end of the period	850				1,783				1,771				850	1,783	1,771
Acquired | Personal Banking | Residential mortgage loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				131				71				18	131	71	18
Provision													(61)	185	146
Charge-offs													(112)	(205)	(252)
Recoveries													125	80	159
Balance at the end of the period	83				131				71				83	131	71
Acquired | Personal Banking | Home equity loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				762				1,047				101	762	1,047	101
Provision													(23)	503	2,065
Charge-offs													(602)	(1,179)	(1,449)
Recoveries													211	391	330
Balance at the end of the period	348				762				1,047				348	762	1,047
Acquired | Personal Banking | Consumer loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				890				653				110	890	653	110
Provision													(335)	765	1,072
Charge-offs													(291)	(795)	(680)
Recoveries													155	267	151
Balance at the end of the period	419				890				653				419	890	653
Acquired | Commercial Banking
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				4,440				3,875				1,473	4,440	3,875	1,473
Provision													(188)	3,609	2,993
Charge-offs													(1,941)	(3,858)	(1,389)
Recoveries													302	814	798
Balance at the end of the period	2,613				4,440				3,875				2,613	4,440	3,875
Acquired | Commercial Banking | Commercial real estate loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				3,549				3,008				1,439	3,549	3,008	1,439
Provision													(467)	2,631	2,116
Charge-offs													(1,291)	(2,830)	(1,337)
Recoveries													205	740	790
Balance at the end of the period	1,996				3,549				3,008				1,996	3,549	3,008
Acquired | Commercial Banking | Commercial loans
Changes in allowance for losses on allocated loans receivable
Balance at the beginning of the period				$ 891				$ 867				$ 34	891	867	34
Provision													279	978	877
Charge-offs													(650)	(1,028)	(52)
Recoveries													97	74	8
Balance at the end of the period	$ 617				$ 891				$ 867				$ 617	$ 891	$ 867

Loans Receivable and Allowanc_9

Loans Receivable and Allowance for Loan Losses - Loan Portfolio by Portfolio Segment and by Class of Financing Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	$ 8,051,439	$ 7,793,409
Allowance for loan losses	55,214	56,795
Recorded investment in loans on nonaccrual	72,281	64,455
Recorded investment in loans 90 days or more past maturity and still accruing	166	502
TDRs	33,608	32,104	$ 42,926
Allowance for loan losses related to TDRs	3,089	3,144
Additional commitments to customers with loans classified as TDRs	388	247
Nonaccrual TDRs	15,306	12,285
Personal Banking
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	4,982,605	4,757,947
Allowance for loan losses	19,168	22,122
Recorded investment in loans on nonaccrual	27,245	28,570
Recorded investment in loans 90 days or more past maturity and still accruing	166	502
TDRs	9,884	9,716
Allowance for loan losses related to TDRs	2,513	1,277
Additional commitments to customers with loans classified as TDRs	4	4
Personal Banking | Residential mortgage loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	2,864,470	2,776,203
Allowance for loan losses	4,137	3,955
Recorded investment in loans on nonaccrual	15,848	14,791
Recorded investment in loans 90 days or more past maturity and still accruing	0	0
TDRs	5,382	8,000
Allowance for loan losses related to TDRs	993	815
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	1,258,422	1,310,355
Allowance for loan losses	3,532	4,834
Recorded investment in loans on nonaccrual	7,075	8,907
Recorded investment in loans 90 days or more past maturity and still accruing	136	120
TDRs	4,502	1,716
Allowance for loan losses related to TDRs	1,520	462
Additional commitments to customers with loans classified as TDRs	4	4
Personal Banking | Consumer Finance Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	3,817	18,619
Allowance for loan losses	676	3,968
Recorded investment in loans on nonaccrual	22	199
Recorded investment in loans 90 days or more past maturity and still accruing	3	3
TDRs	0	0
Allowance for loan losses related to TDRs	0	0
Additional commitments to customers with loans classified as TDRs	0	0
Personal Banking | Consumer loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	855,896	652,770
Allowance for loan losses	10,823	9,365
Recorded investment in loans on nonaccrual	4,300	4,673
Recorded investment in loans 90 days or more past maturity and still accruing	27	379
TDRs	0	0
Allowance for loan losses related to 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	3,068,834	3,035,462
Allowance for loan losses	36,046	34,673
Recorded investment in loans on nonaccrual	45,036	35,885
Recorded investment in loans 90 days or more past maturity and still accruing	0	0
TDRs	23,724	22,388
Allowance for loan losses related to TDRs	576	1,867
Additional commitments to customers with loans classified as TDRs	384	243
Commercial Banking | Commercial real estate loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	2,471,821	2,454,726
Allowance for loan losses	28,375	23,460
Recorded investment in loans on nonaccrual	36,935	28,473
Recorded investment in loans 90 days or more past maturity and still accruing	0	0
TDRs	19,859	15,691
Allowance for loan losses related to TDRs	313	1,125
Additional commitments to customers with loans classified as TDRs	310	235
Commercial Banking | Commercial loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Recorded investment in loans receivable	597,013	580,736
Allowance for loan losses	7,671	11,213
Recorded investment in loans on nonaccrual	8,101	7,412
Recorded investment in loans 90 days or more past maturity and still accruing	0	0
TDRs	3,865	6,697
Allowance for loan losses related to TDRs	263	742
Additional commitments to customers with loans classified as TDRs	$ 74	$ 8

Loans Receivable and Allowan_10

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, 2018	Dec. 31, 2017	Dec. 31, 2016
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	$ 72,281	$ 64,455
Total impaired loans	98,283	84,625	$ 108,061
Average recorded investment in impaired loans	84,338	97,193	118,675
Interest income/ accretion recognized	3,762	3,982	5,596
Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	27,245	28,570
Total impaired loans	35,723	36,833	38,606
Average recorded investment in impaired loans	33,824	35,102	37,420
Interest income/ accretion recognized	1,656	1,552	1,741
Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	45,036	35,885
Total impaired loans	62,560	47,792	69,455
Average recorded investment in impaired loans	50,514	62,091	81,255
Interest income/ accretion recognized	2,106	2,430	3,855
Residential mortgage loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	15,848	14,791
Total impaired loans	22,508	21,605	24,193
Average recorded investment in impaired loans	20,733	21,531	24,483
Interest income/ accretion recognized	910	892	1,079
Home equity loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	7,075	8,907
Total impaired loans	8,893	10,356	9,304
Average recorded investment in impaired loans	9,075	9,150	9,234
Interest income/ accretion recognized	511	452	496
Consumer Finance Loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	22	199
Total impaired loans	22	199	743
Average recorded investment in impaired loans	24	379	772
Interest income/ accretion recognized		20	35
Consumer loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	4,300	4,673
Total impaired loans	4,300	4,673	4,366
Average recorded investment in impaired loans	3,992	4,042	2,931
Interest income/ accretion recognized	235	188	131
Commercial real estate loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	36,935	28,473
Total impaired loans	49,919	37,027	53,928
Average recorded investment in impaired loans	41,328	49,981	64,350
Interest income/ accretion recognized	1,599	1,758	2,864
Commercial loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	8,101	7,412
Total impaired loans	12,641	10,765	15,527
Average recorded investment in impaired loans	9,186	12,110	16,905
Interest income/ accretion recognized	507	672	991
90 days or greater delinquent
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	50,730	43,077	45,181
90 days or greater delinquent | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	22,211	24,576	22,544
90 days or greater delinquent | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	28,519	18,501	22,637
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	12,965	13,509	13,169
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	5,996	7,251	5,552
90 days or greater delinquent | Consumer Finance Loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	22	199	743
90 days or greater delinquent | Consumer loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	3,228	3,617	3,080
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	25,509	15,361	19,264
90 days or greater delinquent | Commercial loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	3,010	3,140	3,373
Less than 90 days delinquent
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	21,551	21,378	34,355
Loans less than 90 days delinquent reviewed for impairment	11,002	5,337	6,459
TDRs less than 90 days delinquent not included elsewhere	15,000	14,833	22,066
Less than 90 days delinquent | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	5,034	3,994	8,694
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	8,478	8,263	7,368
Less than 90 days delinquent | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	16,517	17,384	25,661
Loans less than 90 days delinquent reviewed for impairment	11,002	5,337	6,459
TDRs less than 90 days delinquent not included elsewhere	6,522	6,570	14,698
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	2,883	1,282	5,095
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	6,660	6,814	5,929
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	1,079	1,656	2,313
Loans less than 90 days delinquent reviewed for impairment	0	0	0
TDRs less than 90 days delinquent not included elsewhere	1,818	1,449	1,439
Less than 90 days delinquent | Consumer Finance Loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	0	0	0
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 | Consumer loans | Personal Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	1,072	1,056	1,286
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	11,426	13,112	19,460
Loans less than 90 days delinquent reviewed for impairment	8,549	4,431	3,622
TDRs less than 90 days delinquent not included elsewhere	4,435	4,123	11,582
Less than 90 days delinquent | Commercial loans | Commercial Banking
Composition of impaired loans by portfolio segment and by class of financing receivable
Nonaccrual loans	5,091	4,272	6,201
Loans less than 90 days delinquent reviewed for impairment	2,453	906	2,837
TDRs less than 90 days delinquent not included elsewhere	$ 2,087	$ 2,447	$ 3,116

Loans Receivable and Allowan_11

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, 2018	Dec. 31, 2017
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	$ 7,997,835	$ 7,752,745
Loans individually evaluated for impairment	53,604	40,664
Loans individually evaluated for impairment for which there is a related impairment reserve	48,875	37,411
Related impairment reserve	8,542	3,990
Loans individually evaluated for impairment for which there is no related reserve	4,729	3,253
Personal Banking
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	4,972,298	4,747,578
Loans individually evaluated for impairment	10,307	10,369
Loans individually evaluated for impairment for which there is a related impairment reserve	10,307	10,369
Related impairment reserve	1,276	1,302
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	2,856,359	2,767,635
Loans individually evaluated for impairment	8,111	8,568
Loans individually evaluated for impairment for which there is a related impairment reserve	8,111	8,568
Related impairment reserve	747	816
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	1,256,255	1,308,639
Loans individually evaluated for impairment	2,167	1,716
Loans individually evaluated for impairment for which there is a related impairment reserve	2,167	1,716
Related impairment reserve	523	461
Loans individually evaluated for impairment for which there is no related reserve	0	0
Personal Banking | Consumer Finance Loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	3,817	18,619
Loans individually evaluated for impairment	0	0
Loans individually evaluated for impairment for which there is a related impairment reserve	0	0
Related impairment reserve	0	0
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	855,867	652,685
Loans individually evaluated for impairment	29	85
Loans individually evaluated for impairment for which there is a related impairment reserve	29	85
Related impairment reserve	6	25
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	3,025,537	3,005,167
Loans individually evaluated for impairment	43,297	30,295
Loans individually evaluated for impairment for which there is a related impairment reserve	38,568	27,042
Related impairment reserve	7,266	2,688
Loans individually evaluated for impairment for which there is no related reserve	4,729	3,253
Commercial Banking | Commercial real estate loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	2,436,605	2,433,755
Loans individually evaluated for impairment	35,216	20,971
Loans individually evaluated for impairment for which there is a related impairment reserve	31,830	18,470
Related impairment reserve	6,499	1,859
Loans individually evaluated for impairment for which there is no related reserve	3,386	2,501
Commercial Banking | Commercial loans
Evaluation of impaired loans by portfolio segment and by class of financing receivable
Loans collectively evaluated for impairment	588,932	571,412
Loans individually evaluated for impairment	8,081	9,324
Loans individually evaluated for impairment for which there is a related impairment reserve	6,738	8,572
Related impairment reserve	767	829
Loans individually evaluated for impairment for which there is no related reserve	$ 1,343	$ 752

Loans Receivable and Allowan_12

Loans Receivable and Allowance for Loan Losses - Roll Forward of Troubled Debt Restructurings (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)contract	Dec. 31, 2017USD ($)contract
Number of contract
Beginning balance | contract	205	225
Number of contracts new TDRs | contract	29	24
Number of re-modified TDRs | contract	6	5
Ending balance | contract	195	205
Roll forward of troubled debt restructurings
Beginning TDR balance:	$ 32,104	$ 42,926
New TDRs	1,800	5,450
Re-modified TDRs	3,086	2,099
Net paydowns	(6,606)	(11,538)
Ending TDR balance:	33,608	32,104
Accruing TDRs	18,302	19,819
Non-accrual TDRs	$ 15,306	$ 12,285
Residential mortgage loans
Number of contract
Number of contracts charged off | contract	1	1
Number of contracts paid off | contract	5	0
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ (135)	$ (77)
Amount of contracts paid off	$ 258	$ 0
Home equity loans
Number of contract
Number of contracts charged off | contract	0	1
Number of contracts paid off | contract	5	8
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ 0	$ (48)
Amount of contracts paid off	$ 83	$ (62)
Commercial real estate loans
Number of contract
Number of contracts charged off | contract	2	2
Number of contracts paid off | contract	10	15
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ (294)	$ (2,498)
Amount of contracts paid off	$ 2,254	$ (1,633)
Commercial loans
Number of contract
Number of contracts charged off | contract	7	6
Number of contracts paid off | contract	9	11
Roll forward of troubled debt restructurings
Amount of contracts charged off	$ (1,345)	$ (259)
Amount of contracts paid off	$ 2,403	$ (2,256)

Loans Receivable and Allowan_13

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, 2018USD ($)contract	Dec. 31, 2017USD ($)contract	Dec. 31, 2016USD ($)contract
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	35	29	41
Recorded investment at the time of modification	$ 4,886	$ 7,549	$ 9,779
Current recorded investment	4,815	7,118	7,509
Current allowance	$ 460	$ 599	$ 1,217
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		3	4
Recorded investment at the time of modification		$ 774	$ 962
Current recorded investment		760	958
Current allowance		$ 69	$ 564
Personal Banking
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	26	11	14
Recorded investment at the time of modification	$ 1,390	$ 1,756	$ 1,674
Current recorded investment	1,359	1,703	1,648
Current allowance	$ 222	$ 198	$ 224
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		1	0
Recorded investment at the time of modification		$ 336	$ 0
Current recorded investment		334	0
Current allowance		$ 34	$ 0
Personal Banking | Residential mortgage loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	9	8	7
Recorded investment at the time of modification	$ 754	$ 1,604	$ 1,199
Current recorded investment	749	1,555	1,177
Current allowance	$ 72	$ 158	$ 114
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		1	0
Recorded investment at the time of modification		$ 336	$ 0
Current recorded investment		334	0
Current allowance		$ 34	$ 0
Personal Banking | Home equity loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	17	3	7
Recorded investment at the time of modification	$ 636	$ 152	$ 475
Current recorded investment	610	148	471
Current allowance	$ 150	$ 40	$ 110
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 | Consumer loans
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract			0
Recorded investment at the time of modification			$ 0
Current recorded investment			0
Current allowance			$ 0
Commercial Banking
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	9	18	27
Recorded investment at the time of modification	$ 3,496	$ 5,793	$ 8,105
Current recorded investment	3,456	5,415	5,861
Current allowance	$ 238	$ 401	$ 993
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		2	4
Recorded investment at the time of modification		$ 438	$ 962
Current recorded investment		426	958
Current allowance		$ 35	$ 564
Commercial Banking | Commercial real estate loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	5	11	7
Recorded investment at the time of modification	$ 3,157	$ 5,232	$ 3,729
Current recorded investment	3,114	4,889	3,643
Current allowance	$ 169	$ 364	$ 485
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		2	1
Recorded investment at the time of modification		$ 438	$ 429
Current recorded investment		426	425
Current allowance		$ 35	$ 31
Commercial Banking | Commercial loans
Financing Receivable, Modifications [Line Items]
Number of contracts | contract	4	7	20
Recorded investment at the time of modification	$ 339	$ 561	$ 4,376
Current recorded investment	342	526	2,218
Current allowance	$ 69	$ 37	$ 508
Troubled debt restructurings that subsequently defaulted:
Number of contracts | contract		0	3
Recorded investment at the time of modification		$ 0	$ 533
Current recorded investment		0	533
Current allowance		$ 0	$ 533

Loans Receivable and Allowan_14

Loans Receivable and Allowance for Loan Losses - Troubled Debt Restructurings by Type of Modification (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)contract	Dec. 31, 2017USD ($)contract	Dec. 31, 2016USD ($)contract
Troubled debt restructurings
Number of contracts | contract	35	29	41
Total	$ 4,815	$ 7,118	$ 7,509
Number of re-modified TDRs | contract	6	5
Total	$ 3,046	$ 2,073
Rate
Troubled debt restructurings
Total	71	477
Total	0	262
Payment
Troubled debt restructurings
Total	590	2,688
Total	0	0
Maturity date
Troubled debt restructurings
Total	3,876	2,631
Total	3,046	1,382
Other
Troubled debt restructurings
Total	278	1,322
Total	$ 0	$ 429
Personal Banking
Troubled debt restructurings
Number of contracts | contract	26	11	14
Total	$ 1,359	$ 1,703	$ 1,648
Number of re-modified TDRs | contract	0	3
Total	$ 0	$ 691
Personal Banking | Rate
Troubled debt restructurings
Total	71	477
Total	0	262
Personal Banking | Payment
Troubled debt restructurings
Total	590	0
Total	0	0
Personal Banking | Maturity date
Troubled debt restructurings
Total	420	8
Total	0	0
Personal Banking | Other
Troubled debt restructurings
Total	278	1,218
Total	$ 0	$ 429
Personal Banking | Residential mortgage loans
Troubled debt restructurings
Number of contracts | contract	9	8	7
Total	$ 749	$ 1,555	$ 1,177
Number of re-modified TDRs | contract	0	2
Total	$ 0	$ 679
Personal Banking | Residential mortgage loans | Rate
Troubled debt restructurings
Total	7	359
Total	0	250
Personal Banking | Residential mortgage loans | Payment
Troubled debt restructurings
Total	326	0
Total	0	0
Personal Banking | Residential mortgage loans | Maturity date
Troubled debt restructurings
Total	330	8
Total	0	0
Personal Banking | Residential mortgage loans | Other
Troubled debt restructurings
Total	86	1,188
Total	$ 0	$ 429
Personal Banking | Home equity loans
Troubled debt restructurings
Number of contracts | contract	17	3	7
Total	$ 610	$ 148	$ 471
Number of re-modified TDRs | contract	0	1
Total	$ 0	$ 12
Personal Banking | Home equity loans | Rate
Troubled debt restructurings
Total	64	118
Total	0	12
Personal Banking | Home equity loans | Payment
Troubled debt restructurings
Total	264	0
Total	0	0
Personal Banking | Home equity loans | Maturity date
Troubled debt restructurings
Total	90	0
Total	0	0
Personal Banking | Home equity loans | Other
Troubled debt restructurings
Total	192	30
Total	$ 0	$ 0
Commercial Banking
Troubled debt restructurings
Number of contracts | contract	9	18	27
Total	$ 3,456	$ 5,415	$ 5,861
Number of re-modified TDRs | contract	6	2
Total	$ 3,046	$ 1,382
Commercial Banking | Rate
Troubled debt restructurings
Total	0	0
Total	0	0
Commercial Banking | Payment
Troubled debt restructurings
Total	0	2,688
Total	0	0
Commercial Banking | Maturity date
Troubled debt restructurings
Total	3,456	2,623
Total	3,046	1,382
Commercial Banking | Other
Troubled debt restructurings
Total	0	104
Total	$ 0	$ 0
Commercial Banking | Commercial real estate loans
Troubled debt restructurings
Number of contracts | contract	5	11	7
Total	$ 3,114	$ 4,889	$ 3,643
Number of re-modified TDRs | contract	3	1
Total	$ 2,854	$ 1,299
Commercial Banking | Commercial real estate loans | Rate
Troubled debt restructurings
Total	0	0
Total	0	0
Commercial Banking | Commercial real estate loans | Payment
Troubled debt restructurings
Total	0	2,688
Total	0	0
Commercial Banking | Commercial real estate loans | Maturity date
Troubled debt restructurings
Total	3,114	2,201
Total	2,854	1,299
Commercial Banking | Commercial real estate loans | Other
Troubled debt restructurings
Total	0	0
Total	$ 0	$ 0
Commercial Banking | Commercial loans
Troubled debt restructurings
Number of contracts | contract	4	7	20
Total	$ 342	$ 526	$ 2,218
Number of re-modified TDRs | contract	3	1
Total	$ 192	$ 83
Commercial Banking | Commercial loans | Rate
Troubled debt restructurings
Total	0	0
Total	0	0
Commercial Banking | Commercial loans | Payment
Troubled debt restructurings
Total	0	0
Total	0	0
Commercial Banking | Commercial loans | Maturity date
Troubled debt restructurings
Total	342	422
Total	192	83
Commercial Banking | Commercial loans | Other
Troubled debt restructurings
Total	0	104
Total	$ 0	$ 0

Loans Receivable and Allowan_15

Loans Receivable and Allowance for Loan Losses - Loan Delinquencies (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Loan payment delinquencies
Total delinquency	$ 121,534	$ 117,504
Current	7,929,905	7,675,905
Total loans	8,051,439	7,793,409
90 days or greater delinquent and accruing	143	1,412
Personal Banking
Loan payment delinquencies
Total loans	4,982,605	4,757,947
Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total loans	2,864,470	2,776,203
Personal Banking | Home equity loans
Loan payment delinquencies
Total loans	1,258,422	1,310,355
Personal Banking | Consumer Finance Loans
Loan payment delinquencies
Total loans	3,817	18,619
Personal Banking | Consumer loans
Loan payment delinquencies
Total loans	855,896	652,770
Commercial Banking
Loan payment delinquencies
Total loans	3,068,834	3,035,462
Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total loans	2,471,821	2,454,726
Commercial Banking | Commercial loans
Loan payment delinquencies
Total loans	597,013	580,736
Originated
Loan payment delinquencies
Total delinquency	109,605	98,970
Current	7,303,580	6,869,363
Total loans	7,413,185	6,968,333
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking
Loan payment delinquencies
Total delinquency	73,809	76,209
Current	4,541,001	4,209,714
Total loans	4,614,810	4,285,923
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	44,645	42,429
Current	2,714,474	2,619,951
Total loans	2,759,119	2,662,380
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	13,406	14,470
Current	1,030,472	1,037,088
Total loans	1,043,878	1,051,558
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Consumer Finance Loans
Loan payment delinquencies
Total delinquency	854	3,440
Current	2,963	15,179
Total loans	3,817	18,619
90 days or greater delinquent and accruing	0	0
Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	14,904	15,870
Current	793,092	537,496
Total loans	807,996	553,366
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	35,796	22,761
Current	2,762,579	2,659,649
Total loans	2,798,375	2,682,410
90 days or greater delinquent and accruing	0	0
Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	31,913	18,282
Current	2,217,105	2,142,930
Total loans	2,249,018	2,161,212
90 days or greater delinquent and accruing		0
Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	3,883	4,479
Current	545,474	516,719
Total loans	549,357	521,198
90 days or greater delinquent and accruing		0
Acquired
Loan payment delinquencies
Total delinquency	11,929	18,534
Current	626,325	806,542
Total loans	638,254	825,076
90 days or greater delinquent and accruing	143	1,412
Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	6,705	8,711
Current	361,090	463,313
Total loans	367,795	472,024
90 days or greater delinquent and accruing	65	489
Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	2,542	3,480
Current	91,240	110,343
Total loans	93,782	113,823
90 days or greater delinquent and accruing	19	381
Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	3,345	3,211
Current	211,199	255,586
Total loans	214,544	258,797
90 days or greater delinquent and accruing	40	98
Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	818	2,020
Current	58,651	97,384
Total loans	59,469	99,404
90 days or greater delinquent and accruing	6	10
Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	5,224	9,823
Current	265,235	343,229
Total loans	270,459	353,052
90 days or greater delinquent and accruing	78	923
Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	4,564	8,856
Current	218,239	284,658
Total loans	222,803	293,514
90 days or greater delinquent and accruing	78	923
Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	660	967
Current	46,996	58,571
Total loans	47,656	59,538
90 days or greater delinquent and accruing	0	0
30-59 days delinquent
Loan payment delinquencies
Total delinquency	53,010	56,465
30-59 days delinquent | Originated
Loan payment delinquencies
Total delinquency	49,716	48,759
30-59 days delinquent | Originated | Personal Banking
Loan payment delinquencies
Total delinquency	43,716	41,770
30-59 days delinquent | Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	27,245	23,786
30-59 days delinquent | Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	6,810	6,094
30-59 days delinquent | Originated | Personal Banking | Consumer Finance Loans
Loan payment delinquencies
Total delinquency	661	2,128
30-59 days delinquent | Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	9,000	9,762
30-59 days delinquent | Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	6,000	6,989
30-59 days delinquent | Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	5,391	5,520
30-59 days delinquent | Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	609	1,469
30-59 days delinquent | Acquired
Loan payment delinquencies
Total delinquency	3,294	7,706
30-59 days delinquent | Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	2,818	4,515
30-59 days delinquent | Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	532	1,998
30-59 days delinquent | Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	1,839	1,367
30-59 days delinquent | Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	447	1,150
30-59 days delinquent | Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	476	3,191
30-59 days delinquent | Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	112	2,795
30-59 days delinquent | Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	364	396
60-89 days delinquent
Loan payment delinquencies
Total delinquency	17,651	16,550
60-89 days delinquent | Originated
Loan payment delinquencies
Total delinquency	15,903	14,647
60-89 days delinquent | Originated | Personal Banking
Loan payment delinquencies
Total delinquency	10,542	12,310
60-89 days delinquent | Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	5,732	6,030
60-89 days delinquent | Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	1,771	2,333
60-89 days delinquent | Originated | Personal Banking | Consumer Finance Loans
Loan payment delinquencies
Total delinquency	172	1,113
60-89 days delinquent | Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	2,867	2,834
60-89 days delinquent | Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	5,361	2,337
60-89 days delinquent | Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	4,801	2,133
60-89 days delinquent | Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	560	204
60-89 days delinquent | Acquired
Loan payment delinquencies
Total delinquency	1,748	1,903
60-89 days delinquent | Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	1,162	1,260
60-89 days delinquent | Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	693	205
60-89 days delinquent | Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	294	538
60-89 days delinquent | Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	175	517
60-89 days delinquent | Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	586	643
60-89 days delinquent | Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	586	406
60-89 days delinquent | Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	0	237
90 days or greater delinquent
Loan payment delinquencies
Total delinquency	50,873	44,489
90 days or greater delinquent | Originated
Loan payment delinquencies
Total delinquency	43,986	35,564
90 days or greater delinquent | Originated | Personal Banking
Loan payment delinquencies
Total delinquency	19,551	22,129
90 days or greater delinquent | Originated | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	11,668	12,613
90 days or greater delinquent | Originated | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	4,825	6,043
90 days or greater delinquent | Originated | Personal Banking | Consumer Finance Loans
Loan payment delinquencies
Total delinquency	21	199
90 days or greater delinquent | Originated | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	3,037	3,274
90 days or greater delinquent | Originated | Commercial Banking
Loan payment delinquencies
Total delinquency	24,435	13,435
90 days or greater delinquent | Originated | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	21,721	10,629
90 days or greater delinquent | Originated | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	2,714	2,806
90 days or greater delinquent | Acquired
Loan payment delinquencies
Total delinquency	6,887	8,925
90 days or greater delinquent | Acquired | Personal Banking
Loan payment delinquencies
Total delinquency	2,725	2,936
90 days or greater delinquent | Acquired | Personal Banking | Residential mortgage loans
Loan payment delinquencies
Total delinquency	1,317	1,277
90 days or greater delinquent | Acquired | Personal Banking | Home equity loans
Loan payment delinquencies
Total delinquency	1,212	1,306
90 days or greater delinquent | Acquired | Personal Banking | Consumer loans
Loan payment delinquencies
Total delinquency	196	353
90 days or greater delinquent | Acquired | Commercial Banking
Loan payment delinquencies
Total delinquency	4,162	5,989
90 days or greater delinquent | Acquired | Commercial Banking | Commercial real estate loans
Loan payment delinquencies
Total delinquency	3,866	5,655
90 days or greater delinquent | Acquired | Commercial Banking | Commercial loans
Loan payment delinquencies
Total delinquency	$ 296	$ 334

Loans Receivable and Allowan_16

Loans Receivable and Allowance for Loan Losses - Credit Quality Indicators (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Credit quality indicators
Total loans	$ 8,051,439	$ 7,793,409
Pass
Credit quality indicators
Total loans	7,753,667	7,452,732
Special mention
Credit quality indicators
Total loans	113,969	102,834
Substandard
Credit quality indicators
Total loans	183,803	237,843
Doubtful
Credit quality indicators
Total loans	0	0
Loss
Credit quality indicators
Total loans	0	0
Special mention or substandard | Minimum
Credit quality indicators
Total loans	1,000
Personal Banking
Credit quality indicators
Total loans	4,982,605	4,757,947
Personal Banking | Residential mortgage loans
Credit quality indicators
Total loans	2,864,470	2,776,203
Personal Banking | Home equity loans
Credit quality indicators
Total loans	1,258,422	1,310,355
Personal Banking | Consumer Finance Loans
Credit quality indicators
Total loans	3,817	18,619
Personal Banking | Consumer loans
Credit quality indicators
Total loans	855,896	652,770
Commercial Banking
Credit quality indicators
Total loans	3,068,834	3,035,462
Commercial Banking | Commercial real estate loans
Credit quality indicators
Total loans	2,471,821	2,454,726
Commercial Banking | Commercial loans
Credit quality indicators
Total loans	597,013	580,736
Originated
Credit quality indicators
Total loans	7,413,185	6,968,333
Originated | Pass
Credit quality indicators
Total loans	7,161,796	6,682,937
Originated | Special mention
Credit quality indicators
Total loans	106,902	94,209
Originated | Substandard
Credit quality indicators
Total loans	144,487	191,187
Originated | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Loss
Credit quality indicators
Total loans	0	0
Originated | Personal Banking
Credit quality indicators
Total loans	4,614,810	4,285,923
Originated | Personal Banking | Pass
Credit quality indicators
Total loans	4,595,403	4,256,410
Originated | Personal Banking | Special mention
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Substandard
Credit quality indicators
Total loans	19,407	29,513
Originated | Personal Banking | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Loss
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Residential mortgage loans
Credit quality indicators
Total loans	2,759,119	2,662,380
Originated | Personal Banking | Residential mortgage loans | Pass
Credit quality indicators
Total loans	2,749,266	2,645,475
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	9,853	16,905
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	0
Originated | Personal Banking | Home equity loans
Credit quality indicators
Total loans	1,043,878	1,051,558
Originated | Personal Banking | Home equity loans | Pass
Credit quality indicators
Total loans	1,038,245	1,042,965
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	5,633	8,593
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 Finance Loans
Credit quality indicators
Total loans	3,817	18,619
Originated | Personal Banking | Consumer Finance Loans | Pass
Credit quality indicators
Total loans	3,817	18,420
Originated | Personal Banking | Consumer Finance Loans | Special mention
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Consumer Finance Loans | Substandard
Credit quality indicators
Total loans	0	199
Originated | Personal Banking | Consumer Finance Loans | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Consumer Finance Loans | Loss
Credit quality indicators
Total loans	0	0
Originated | Personal Banking | Consumer loans
Credit quality indicators
Total loans	807,996	553,366
Originated | Personal Banking | Consumer loans | Pass
Credit quality indicators
Total loans	804,075	549,550
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	3,921	3,816
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	2,798,375	2,682,410
Originated | Commercial Banking | Pass
Credit quality indicators
Total loans	2,566,393	2,426,527
Originated | Commercial Banking | Special mention
Credit quality indicators
Total loans	106,902	94,209
Originated | Commercial Banking | Substandard
Credit quality indicators
Total loans	125,080	161,674
Originated | Commercial Banking | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Commercial Banking | Loss
Credit quality indicators
Total loans	0	0
Originated | Commercial Banking | Commercial real estate loans
Credit quality indicators
Total loans	2,249,018	2,161,212
Originated | Commercial Banking | Commercial real estate loans | Pass
Credit quality indicators
Total loans	2,062,728	1,964,565
Originated | Commercial Banking | Commercial real estate loans | Special mention
Credit quality indicators
Total loans	91,142	78,699
Originated | Commercial Banking | Commercial real estate loans | Substandard
Credit quality indicators
Total loans	95,148	117,948
Originated | Commercial Banking | Commercial real estate loans | Doubtful
Credit quality indicators
Total loans	0	0
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	549,357	521,198
Originated | Commercial Banking | Commercial loans | Pass
Credit quality indicators
Total loans	503,665	461,962
Originated | Commercial Banking | Commercial loans | Special mention
Credit quality indicators
Total loans	15,760	15,510
Originated | Commercial Banking | Commercial loans | Substandard
Credit quality indicators
Total loans	29,932	43,726
Originated | Commercial Banking | Commercial loans | Doubtful
Credit quality indicators
Total loans	0	0
Originated | Commercial Banking | Commercial loans | Loss
Credit quality indicators
Total loans	0	0
Acquired
Credit quality indicators
Total loans	638,254	825,076
Acquired | Pass
Credit quality indicators
Total loans	591,871	769,795
Acquired | Special mention
Credit quality indicators
Total loans	7,067	8,625
Acquired | Substandard
Credit quality indicators
Total loans	39,316	46,656
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	367,795	472,024
Acquired | Personal Banking | Pass
Credit quality indicators
Total loans	364,852	468,961
Acquired | Personal Banking | Special mention
Credit quality indicators
Total loans	0	0
Acquired | Personal Banking | Substandard
Credit quality indicators
Total loans	2,943	3,063
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	93,782	113,823
Acquired | Personal Banking | Residential mortgage loans | Pass
Credit quality indicators
Total loans	92,625	112,990
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	1,157	833
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	214,544	258,797
Acquired | Personal Banking | Home equity loans | Pass
Credit quality indicators
Total loans	213,273	257,312
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	1,271	1,485
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	59,469	99,404
Acquired | Personal Banking | Consumer loans | Pass
Credit quality indicators
Total loans	58,954	98,659
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	515	745
Acquired | Personal Banking | Consumer loans | Doubtful
Credit quality indicators
Total loans		0
Acquired | Personal Banking | Consumer loans | Loss
Credit quality indicators
Total loans	0	0
Acquired | Commercial Banking
Credit quality indicators
Total loans	270,459	353,052
Acquired | Commercial Banking | Pass
Credit quality indicators
Total loans	227,019	300,834
Acquired | Commercial Banking | Special mention
Credit quality indicators
Total loans	7,067	8,625
Acquired | Commercial Banking | Substandard
Credit quality indicators
Total loans	36,373	43,593
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	222,803	293,514
Acquired | Commercial Banking | Commercial real estate loans | Pass
Credit quality indicators
Total loans	191,622	251,761
Acquired | Commercial Banking | Commercial real estate loans | Special mention
Credit quality indicators
Total loans	3,546	4,838
Acquired | Commercial Banking | Commercial real estate loans | Substandard
Credit quality indicators
Total loans	27,635	36,915
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	47,656	59,538
Acquired | Commercial Banking | Commercial loans | Pass
Credit quality indicators
Total loans	35,397	49,073
Acquired | Commercial Banking | Commercial loans | Special mention
Credit quality indicators
Total loans	3,521	3,787
Acquired | Commercial Banking | Commercial loans | Substandard
Credit quality indicators
Total loans	8,738	6,678
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 Allowan_17

Loans Receivable and Allowance for Loan Losses - Off-Balance Sheet Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	$ 957,603,000	$ 1,079,476,000
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	136,760,000	181,058,000
Outstanding loan commitments for fixed rate loans	60,700,000
Outstanding loan commitments for adjustable rate loans	78,000,000
Undisbursed lines of credit
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	788,262,000	872,700,000
Standby letters of credit
Financial instruments with off-balance-sheet risk
Financial instruments with off-balance-sheet risk	32,581,000	25,718,000
Maximum potential amount of future payments	39,700,000
Maximum potential amount of future payments fully collateralized	32,600,000
Liability recognized for the obligations	$ 267,000	$ 169,000

Loans Receivable and Allowan_18

Loans Receivable and Allowance for Loan Losses - Mortgage Servicing Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Servicing Asset at Amortized Cost, Gross, Balance [Roll Forward]
Servicing rights, balance	$ 3,523	$ 4,239
Additions	50	833
Amortization	(1,470)	(1,549)
Servicing rights, balance	2,103	3,523
Valuation Allowance for Impairment of Recognized Servicing Assets [Roll Forward]
Valuation allowance, balance	0	(4)
Additions	0	4
Valuation allowance, balance	0	0
Servicing Asset at Amortized Cost, Balance [Roll Forward]
Net carrying and fair value, balance	3,523	4,235
Additions	50	837
Amortization	(1,470)	(1,549)
Net carrying and fair value, balance	$ 2,103	$ 3,523

Accrued Interest Receivable (De

Accrued Interest Receivable (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Interest Receivable and Other Assets [Abstract]
Investment securities	$ 1,035	$ 1,260
Mortgage-backed securities	1,333	1,107
Loans receivable	22,122	20,985
Accrued interest receivable	$ 24,490	$ 23,352

Federal Home Loan Bank Stock (D

Federal Home Loan Bank Stock (Details) - Federal Home Loan Bank of Pittsburgh $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)capital_stock	Dec. 31, 2017USD ($)
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
FHLB Stock	$ 15,600	$ 11,700
Dividend received on capital stock	$ 452	$ 250
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, 2018	Dec. 31, 2017	Dec. 31, 2016
Premises and Equipment
Total, at cost	$ 308,618	$ 316,875
Less accumulated depreciation and amortization	(165,228)	(164,931)
Premises and equipment, net	143,390	151,944
Depreciation and amortization expense	12,100	12,400	$ 13,700
Land and land improvements
Premises and Equipment
Total, at cost	21,042	21,563
Office buildings and improvements
Premises and Equipment
Total, at cost	150,328	150,056
Furniture, fixtures and equipment
Premises and Equipment
Total, at cost	119,829	125,347
Leasehold improvements
Premises and Equipment
Total, at cost	$ 17,419	$ 19,909

Premises and Equipment - Minimu

Premises and Equipment - Minimum Annual Rentals by Fiscal Year (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Minimum annual rentals
2,019	$ 4,677
2,020	3,884
2,021	3,179
2,022	2,465
2,023	2,040
Thereafter	7,784
Total	24,029
Rental expense	$ 5,400	$ 5,600	$ 5,300

Goodwill and Other Intangible_3

Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Amortizable intangible assets:
Amortization expense	$ 5,848	$ 6,764	$ 4,259
Estimated amortization expense
For the year ended December 31, 2019	4,933
For the year ending December 31, 2020	4,017
For the year ending December 31, 2021	3,188
For the year ending December 31, 2022	2,456
For the year ending December 31, 2023	1,847
Core Deposits
Amortizable intangible assets:
Intangible asset - gross	63,685	63,685
Acquisitions	0	0
Less: accumulated amortization	(45,027)	(40,029)
Intangible asset - net	18,658	23,656
Customer and Contract
Amortizable intangible assets:
Intangible asset - gross	10,474	10,474
Acquisitions	0	0
Less: accumulated amortization	(9,311)	(8,461)
Intangible asset - net	$ 1,163	$ 2,013

Goodwill and Other Intangible_4

Goodwill and Other Intangible Assets - Changes in the Carrying Amount of Goodwill (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Changes in the carrying amount of goodwill
Balance at the beginning of the period	$ 307,420,000	$ 307,420,000
Goodwill acquired	0	0
Balance at the end of the period	307,420,000	307,420,000
Goodwill impairment	$ 0	$ 0

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deposits [Abstract]
Savings deposits	$ 1,636,099	$ 1,653,579
Interest-bearing demand deposits	1,455,460	1,442,928
Noninterest-bearing demand deposits	1,736,156	1,610,409
Money market deposit accounts	1,661,623	1,707,450
Time deposits	1,404,841	1,412,623
Total deposits	7,894,179	7,826,989
Aggregate amount of certificates of deposit with a minimum denomination of $100,000	460,800	436,400
Deposits in accounts exceeding $250,000	1,675,000
Contractual maturity of the certificate accounts
Due within 12 months	553,173	666,348
Due between 12 and 24 months	352,074	226,171
Due between 24 and 36 months	213,591	201,654
Due between 36 and 48 months	171,866	131,530
Due between 48 and 60 months	108,068	174,704
After 60 months	6,069	12,216
Total time deposits	1,404,841	1,412,623
Interest expense incurred on deposits
Savings deposits	3,064	3,062	$ 3,218
Interest-bearing demand deposits	3,607	1,027	462
Money market deposit accounts	5,740	4,203	3,621
Time deposits	18,574	14,765	16,164
Total interest expense	$ 30,985	$ 23,057	$ 23,465

Borrowed Funds - Schedule of Bo

Borrowed Funds - Schedule of Borrowed Funds (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Debt Instrument [Line Items]
Borrowed funds	$ 234,389	$ 108,238
Term notes payable to the FHLB of Pittsburgh:
Debt Instrument [Line Items]
Due within one year, amount	128,600	0
Borrowed funds	$ 128,600	$ 0
Due within one year, average rate	2.60%	0.00%
Collateralized borrowings, due within one year
Debt Instrument [Line Items]
Due within one year, amount	$ 105,789	$ 108,238
Borrowed funds	$ 234,389
Due within one year, average rate	0.20%	0.20%

Borrowed Funds - Narrative (Det

Borrowed Funds - Narrative (Details)	Dec. 15, 2005USD ($)$ / sharesshares	Dec. 05, 2005USD ($)$ / sharesshares	Dec. 31, 2018USD ($)trust$ / sharesshares	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Debt Instrument [Line Items]
Number of statutory business trusts owned | trust			3
Junior subordinated deferrable interest debentures held by trusts that issued guaranteed capital debt securities			$ 111,213,000	$ 111,213,000
FHLB of Pittsburgh
Debt Instrument [Line Items]
Maximum commitment			150,000,000
Collateralized borrowings, due within one year
Debt Instrument [Line Items]
Due within one year, amount			105,789,000	108,238,000
Average amount of agreements outstanding			102,300,000	121,000,000	$ 141,600,000
Maximum amount of outstanding security repurchase agreement			110,300,000	137,200,000	$ 158,400,000
Trust preferred investments
Debt Instrument [Line Items]
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
Debt Instrument [Line Items]
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)			4.18%
Trust preferred investments | Northwest Bancorp Statutory Trust IV
Debt Instrument [Line Items]
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)			4.17%
Trust preferred investments | LNB Trust II
Debt Instrument [Line Items]
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
Effective interest rate (as a percent)			4.27%
Cumulative Preferred Stock | Trust preferred investments | LNB Trust II
Debt Instrument [Line Items]
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 II
Debt Instrument [Line Items]
Spread on variable rate basis (as a percent)			1.48%

Borrowed Funds - Schedule of Ca

Borrowed Funds - Schedule of Capital Debt Securities (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017	Dec. 15, 2005	Dec. 05, 2005
Debt Instrument [Line Items]
Junior subordinated debentures	$ 111,213,000	$ 111,213,000
Trust preferred investments
Debt Instrument [Line Items]
Junior subordinated debentures	111,213,000	111,213,000
Total value of cumulative trust preferred securities issued	107,875,000
Trust preferred investments | Northwest Bancorp Capital Trust III
Debt Instrument [Line Items]
Junior subordinated debentures	51,547,000	51,547,000
Total value of cumulative trust preferred securities issued	50,000,000			$ 50,000,000
Trust preferred investments | Northwest Bancorp Statutory Trust IV
Debt Instrument [Line Items]
Junior subordinated debentures	51,547,000	51,547,000
Total value of cumulative trust preferred securities issued	50,000,000		$ 50,000,000
Trust preferred investments | LNB Trust II
Debt Instrument [Line Items]
Junior subordinated debentures	8,119,000	$ 8,119,000
Total value of cumulative trust preferred securities issued	$ 7,875,000

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Allocation of total income tax
Income before income taxes	$ 7,547	$ 7,035	$ 6,900	$ 6,940	$ 6,576	$ 12,414	$ 14,402	$ 8,052	$ 12,361	$ 4,697	$ (3,491)	$ 8,081	$ 28,422	$ 41,444	$ 21,648
Shareholders’ equity for unrealized loss on securities available-for-sale													(573)	(3,403)	(1,871)
Shareholders’ equity for tax benefit for excess of fair value above cost of stock benefit plans													0	0	(1,425)
Shareholders’ equity for pension adjustment													(24)	(213)	(2,455)
Shareholders’ equity for swap fair value adjustment													223	585	539
Unallocated income tax													28,048	38,413	16,436
Income tax expense applicable to income before taxes
Current													31,192	30,127	18,914
Deferred													(2,770)	11,317	2,734
Total provision for income taxes	7,547	$ 7,035	$ 6,900	$ 6,940	6,576	$ 12,414	$ 14,402	$ 8,052	$ 12,361	$ 4,697	$ (3,491)	$ 8,081	$ 28,422	$ 41,444	$ 21,648
Reconciliation of the expected federal statutory income tax rate to the effective rate
Expected tax rate (as a percent)													21.00%	35.00%	35.00%
Tax-exempt interest income (as a percent)													(0.90%)	(1.50%)	(3.30%)
State income tax, net of federal benefit (as a percent)													3.80%	3.20%	1.20%
Bank-owned life insurance (as a percent)													(0.90%)	(1.60%)	(2.60%)
Stock-based compensation (as a percent)													(0.80%)	(0.90%)	(0.00%)
Dividends on stock plans (as a percent)													(0.60%)	(1.10%)	(2.00%)
Low income housing and historic tax credits (as a percent)													(0.60%)	(0.50%)	(1.00%)
ESOP termination (as a percent)													0.00%	0.00%	3.40%
Adjustment to net deferred tax liabilities for enacted changes in tax laws and rates (as a percent)													0.00%	(2.30%)	0.00%
Other (as a percent)													0.20%	0.20%	(0.30%)
Effective tax rate (as a percent)													21.20%	30.50%	30.40%
Deferred tax assets:
Deferred rent	115				87								$ 115	$ 87
Deferred compensation expense	2,357				1,040								2,357	1,040
Bad debts	11,257				10,277								11,257	10,277
Other reserves	1,065				953								1,065	953
Accrued postretirement benefit cost	410				413								410	413
Stock benefit plans	904				744								904	744
Writedown of investment securities	0				104								0	104
Accrued expenses	0				35								0	35
Pension and postretirement benefits	13,057				13,033								13,057	13,033
Unrealized loss on the fair value of derivatives	0				223								0	223
Unrealized loss on the fair value of securities available-for-sale	2,733				2,160								2,733	2,160
Deferred income	822				1,001								822	1,001
Other	219				141								219	141
Total deferred tax assets	32,939				30,211								32,939	30,211
Deferred tax liabilities:
Pension expense	5,686				5,542								5,686	5,542
Purchase accounting	180				303								180	303
Intangible assets	13,839				13,546								13,839	13,546
Mortgage servicing rights	460				777								460	777
Fixed assets	4,602				4,940								4,602	4,940
Net deferred loan costs	4,558				4,690								4,558	4,690
Other	331				274								331	274
Total deferred tax liabilities	29,656				30,072								29,656	30,072
Net deferred tax asset	$ 3,283				$ 139								$ 3,283	$ 139

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	12 Months Ended
	Dec. 31, 2018USD ($)
Income Tax Disclosure [Abstract]
Valuation allowance for deferred tax assets	$ 0
Operating loss carryforwards
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
Income tax benefit, due to tax reform	3,100,000
State and Local Jurisdiction
Operating loss carryforwards
Income tax examination, additional tax liability	444,000
Domestic Tax Authority | LNB
Operating loss carryforwards
Income tax examination, additional tax liability	$ 0

Shareholders' Equity (Details)

Shareholders' Equity (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
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) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Stock options
Antidilutive securities excluded from the calculation of earnings per share
Average share price during the reporting period (in dollars per share)	$ 17.20	$ 16.64	$ 14.79

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, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Earnings Per Share [Abstract]
Net income available to common shareholders	$ 26,467	$ 27,740	$ 26,299	$ 24,985	$ 22,148	$ 23,591	$ 30,982	$ 17,746	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 105,491	$ 94,467	$ 49,667
Weighted average common shares outstanding (in shares)													102,073,888	101,015,083	99,439,174
Dilutive potential shares due to effect of stock options (in shares)													1,492,013	1,549,822	1,225,514
Total weighted average common shares and dilutive potential shares (in shares)													103,565,901	102,564,905	100,664,688
Basic earnings per share (in dollars per share)	$ 0.26	$ 0.27	$ 0.26	$ 0.25	$ 0.22	$ 0.23	$ 0.31	$ 0.18	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 1.03	$ 0.94	$ 0.50
Diluted earnings per share (in dollars per share)	$ 0.26	$ 0.27	$ 0.25	$ 0.24	$ 0.22	$ 0.23	$ 0.30	$ 0.17	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 1.02	$ 0.92	$ 0.49

Employee Benefit Plans - Pensio

Employee Benefit Plans - Pension Plans, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee benefit plans
Employer matching contribution	100.00%
Employee matching contribution	4.00%
Total expense for all retirement plans	$ 5.8	$ 6.8	$ 5.8
Pension Plans
Employee benefit plans
Estimated net loss that will be amortized from accumulated other comprehensive income into net periodic cost over the next year	3.3
Prior service credit that will be amortized from accumulated other comprehensive income into net periodic cost over the next year	(2.3)
Accumulated benefit obligation for funded defined benefit pension plan	175.1	186.9	165.9
Accumulated benefit obligation for unfunded defined benefit pension plan	$ 4.8	$ 6.2	$ 6.3
Target allocation of any one stock, maximum (as a percent)	10.00%
Maximum average maturity of bond portfolio	10 years
2,019	$ 7.2
2,020	7.5
2,021	7.8
2,022	7.7
2,023	7.8
2024 to 2028	44.1
Pension Plans | Minimum
Employee benefit plans
Contributions to defined benefit pension plan	2
Pension Plans | Maximum
Employee benefit plans
Contributions to defined benefit pension plan	$ 4
Pension Plans | Equity securities | Minimum
Employee benefit plans
Target allocation, (as a percent)	30.00%	30.00%
Pension Plans | Equity securities | Maximum
Employee benefit plans
Target allocation, (as a percent)	60.00%	60.00%
Pension Plans | Debt securities | Minimum
Employee benefit plans
Target allocation, (as a percent)	20.00%	20.00%
Pension Plans | Debt securities | Maximum
Employee benefit plans
Target allocation, (as a percent)	50.00%	50.00%

Employee Benefit Plans - Pens_2

Employee Benefit Plans - Pension Plans - Components of Net Periodic Pension Cost and Other Amounts Recognized In OCI (Details) - Pension Plans - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Components of net periodic pension cost
Service cost	$ 6,864	$ 6,149	$ 5,496
Interest cost	6,712	6,879	6,781
Expected return on plan assets	(11,968)	(10,512)	(9,897)
Net amortization and deferral	1,167	1,388	1,388
Net periodic pension cost	2,775	3,904	3,768
Changes in the defined benefit pension plans’ plan assets and benefit obligations recognized in other comprehensive income
Net (gain)/loss	(1,716)	(1,647)	1,550
Prior service cost	0	0	0
Amortization of prior service cost	2,323	2,323	2,323
Total recognized in other comprehensive income	607	676	3,873
Total recognized in net periodic benefit cost and other comprehensive income	$ 3,382	$ 4,580	$ 7,641

Employee Benefit Plans - Define

Employee Benefit Plans - Defined Benefit Pension Plans' Funded Status (Details) - Pension Plans - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Change in benefit obligation:
Benefit obligation at beginning of year	$ 193,142	$ 172,208
Service cost	6,864	6,149	$ 5,496
Interest cost	6,712	6,879	6,781
Actuarial (gain)/loss	(19,015)	14,807
Benefits paid	(6,582)	(6,901)
Benefit obligation at end of year	181,121	193,142	172,208
Change in plan assets:
Fair value of plan assets at beginning of year	173,668	152,625
Actual return on plan assets	(8,820)	23,255
Employer contributions	2,500	4,689
Benefits paid	(6,582)	(6,901)
Fair value of plan assets at end of period	160,766	173,668	$ 152,625
Funded status at end of year	$ (20,355)	$ (19,474)
Assumptions used to develop the net periodic pension cost
Discount rate	3.53%	4.06%	4.25%
Expected long-term rate of return on assets	7.00%	7.00%	7.00%
Rate of increase in compensation levels	3.00%	3.00%	3.00%
Assumptions used to determine benefit obligations
Discount rate	4.15%	3.53%	4.06%
Expected long-term rate of return on assets	7.00%	7.00%	7.00%
Rate of increase in compensation levels	3.00%	3.00%	3.00%

Employee Benefit Plans - Defi_2

Employee Benefit Plans - Defined Benefit Plans Certain Information and Weighted Average Asset Allocation (Details) - Pension Plans - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee benefit plans
Projected benefit obligation	$ 181,121	$ 193,142	$ 172,208
Accumulated benefit obligation	181,121	193,142
Fair value of plan assets	$ 160,766	$ 173,668	$ 152,625
Weighted average asset allocation of defined benefit plans
Total (as a percent)	100.00%	100.00%
Debt securities
Weighted average asset allocation of defined benefit plans
Total (as a percent)	27.00%	23.00%
Equity securities
Weighted average asset allocation of defined benefit plans
Total (as a percent)	70.00%	73.00%
Other
Weighted average asset allocation of defined benefit plans
Total (as a percent)	3.00%	4.00%
Minimum | Debt securities
Weighted average asset allocation of defined benefit plans
Target allocation, (as a percent)	20.00%	20.00%
Minimum | Equity securities
Weighted average asset allocation of defined benefit plans
Target allocation, (as a percent)	30.00%	30.00%
Minimum | Other
Weighted average asset allocation of defined benefit plans
Target allocation, (as a percent)	5.00%	5.00%
Maximum | Debt securities
Weighted average asset allocation of defined benefit plans
Target allocation, (as a percent)	50.00%	50.00%
Maximum | Equity securities
Weighted average asset allocation of defined benefit plans
Target allocation, (as a percent)	60.00%	60.00%
Maximum | Other
Weighted average asset allocation of defined benefit plans
Target allocation, (as a percent)	50.00%	50.00%

Employee Benefit Plans - Pens_3

Employee Benefit Plans - Pension Plan Assets (Details) - Pension Plans - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee benefit plans
Fair value of plan assets	$ 160,766	$ 173,668	$ 152,625
Level 1 | Mutual funds - debt
Employee benefit plans
Fair value of plan assets	43,549	40,010
Level 1 | Mutual funds - equity
Employee benefit plans
Fair value of plan assets	112,580	125,871
Level 1 | Cash and cash equivalents
Employee benefit plans
Fair value of plan assets	$ 4,637	$ 7,787

Employee Benefit Plans - Postre

Employee Benefit Plans - Postretirement Healthcare Plan, Narrative (Details) - Postretirement Healthcare Plan $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Requisite service age, minimum	55 years
Estimated net loss that will be amortized from accumulated other comprehensive income into net periodic cost over the next year	$ 68
Effect of one percentage point increase on healthcare cost (as a percent)	5.00%
Effect of 1-percent increase in assumed health care cost trend rates on interest cost in current period	$ 7
Effect of 1-percent increase in assumed health care cost trend rates on postretirement benefit obligation	$ 43

Employee Benefit Plans - Post_2

Employee Benefit Plans - Postretirement Healthcare Plan - Components of Net Periodic Benefit Cost and Other Amounts Recognized in OCI (Details) - Postretirement Healthcare Plan - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Interest cost	$ 54	$ 68	$ 70
Net amortization and deferral	98	108	90
Net periodic pension cost	152	176	160
Net (gain)/loss	(305)	(156)	109
Total recognized in other comprehensive income	(305)	(156)	109
Total recognized in net periodic benefit cost and other comprehensive income	$ (153)	$ 20	$ 269

Employee Benefit Plans - Post_3

Employee Benefit Plans - Postretirement Healthcare Plan - Funded Status (Details) - Postretirement Healthcare Plan - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018	Dec. 31, 2017
Change in benefit obligation:
Benefit obligation at beginning of year	$ 1,637,000	$ 1,779,000
Interest cost	54,000	68,000	$ 70,000
Actuarial (gain)/loss	(207,000)	(48,000)
Benefits paid	(152,000)	(162,000)
Benefit obligation at end of year	1,332,000	1,637,000	$ 1,779,000
Change in plan assets:
Employer contributions	152,000	162,000
Benefits paid	$ (152,000)	$ (162,000)
Funded status at end of year				$ (1,332,000)	$ (1,637,000)
Defined Benefit Plan, Assumptions Used in Calculations [Abstract]
Discount rate	3.53%	4.06%	4.25%
Monthly cost of healthcare insurance per beneficiary	$ 507	$ 548	$ 539
Annual rate of increase in healthcare costs	4.00%	4.00%	4.00%
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligation	$ 1,637,000	$ 1,779,000	$ 1,779,000	1,332,000	1,637,000
Accumulated benefit obligation				$ 1,332,000	$ 1,637,000

Employee Benefit Plans - Employ

Employee Benefit Plans - Employee Stock Ownership Plan, Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2016USD ($)
Employee Stock Ownership Plan
Employee Stock Ownership Plan (ESOP) Disclosures [Line Items]
Compensation expense	$ 6.3

Employee Benefit Plans - Common

Employee Benefit Plans - Common Stock Awards, Narrative (Details) - Restricted common shares - USD ($) $ / shares in Units, $ in Millions	May 14, 2018	May 17, 2017	May 18, 2016	Dec. 31, 2018	Dec. 31, 2017	Apr. 20, 2011
Stock Related Compensation
Weighted average grant date fair value of shares issued (in dollars per share)	$ 16.59	$ 15.24	$ 14.51
Market value of shares issued	$ 6.9	$ 5.8	$ 4.9
Number of shares forfeited				496,091
Vesting period				7 years	10 years
2011 Equity Incentive Plan
Stock Related Compensation
Number of shares authorized						2,806,233
Number of shares forfeited				415,154
Employees
Stock Related Compensation
Number of shares awarded	390,030	378,050	310,160	390,030	353,750
Director
Stock Related Compensation
Number of shares awarded	24,300	24,300	24,300	24,300	24,300
2015 issuance
Stock Related Compensation
Percentage of granted awards which will vest				30.00%
2016 issuance
Stock Related Compensation
Percentage of granted awards which will vest				20.00%
2017 issuance
Stock Related Compensation
Percentage of granted awards which will vest				10.00%

Employee Benefit Plans - Stock

Employee Benefit Plans - Stock Option Plans, Narrative (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	May 14, 2018	May 17, 2017	May 18, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Outstanding and exercisable options
Granted (in shares)				895,960	819,010	725,400
Weighted average fair value of options at grant date (in dollars per share)				$ 1.49	$ 1.55	$ 1.52
Granted (in dollars per share)	$ 16.59	$ 15.57	$ 14.15	$ 16.59	$ 15.57	$ 14.15
Vesting period				7 years	10 years
Exercise period				10 years
Aggregate intrinsic value of all options expected to vest				$ 8.6
Aggregate intrinsic value of all options fully vested				$ 14.3
2011 Equity Incentive Plan
Outstanding and exercisable options
Number of shares authorized				7,015,583
Employees
Outstanding and exercisable options
Granted (in shares)	831,160	754,210	660,600	831,160	754,210
Director
Outstanding and exercisable options
Granted (in shares)	64,800	64,800	64,800	64,800	64,800

Employee Benefit Plans - Share-

Employee Benefit Plans - Share-Based Awards (Details) - Stock options - USD ($) $ / shares in Units, $ in Millions	May 14, 2018	May 17, 2017	May 18, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Number
Balance at beginning of year (in shares)				5,695,570	5,804,105	6,306,496
Granted (in shares)				895,960	819,010	725,400
Exercised (in shares)				(830,712)	(630,591)	(1,081,072)
Forfeited/ expired (in shares)				(148,006)	(296,954)	(146,719)
Balance at end of year (in shares)				5,612,812	5,695,570	5,804,105
Exercisable at end of year (in shares)				3,016,175	3,016,367	3,035,718
Weighted average exercise price
Balance at beginning of year (in dollars per share)				$ 12.75	$ 12.25	$ 11.81
Granted (in dollars per share)	$ 16.59	$ 15.57	$ 14.15	16.59	15.57	14.15
Exercised (in dollars per share)				10.38	11.66	11.01
Forfeited (in dollars per share)				12.52	12.43	12.71
Balance at end of year (in dollars per share)				13.49	12.75	12.25
Exercisable at end of year (in dollars per share)				12.61	11.99	11.71
Weighted average fair value of options at grant date (in dollars per share)				$ 1.49	$ 1.55	$ 1.52
Intrinsic value of options exercised				$ 4.8	$ 3.5	$ 5.1

Employee Benefit Plans - Number

Employee Benefit Plans - Number of Options Outstanding and Exercisable and Weighted Average Remaining Life of All Option Grants (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Exercise price $7.48
Options outstanding:
Number of options (in shares)	106,041
Weighted average remaining contract life (years)	1 year
Options exercisable:
Number of options (in shares)	106,041
Weighted average remaining term - vested (years)	1 year
Exercise price $9.79
Options outstanding:
Number of options (in shares)	2,250
Weighted average remaining contract life (years)	3 months
Options exercisable:
Number of options (in shares)	2,250
Weighted average remaining term - vested (years)	3 months
Exercise price $16.59
Options outstanding:
Number of options (in shares)	869,718
Weighted average remaining contract life (years)	9 years 3 months
Options exercisable:
Number of options (in shares)	156,040
Weighted average remaining term - vested (years)	9 years 3 months
Exercise price $11.49
Options outstanding:
Number of options (in shares)	205,326
Weighted average remaining contract life (years)	2 years
Options exercisable:
Number of options (in shares)	211,239
Weighted average remaining term - vested (years)	2 years
Exercise price $11.70
Options outstanding:
Number of options (in shares)	339,197
Weighted average remaining contract life (years)	3 years 3 months
Options exercisable:
Number of options (in shares)	246,865
Weighted average remaining term - vested (years)	3 years 3 months
Exercise price $12.12
Options outstanding:
Number of options (in shares)	246,618
Weighted average remaining contract life (years)	3 years
Options exercisable:
Number of options (in shares)	255,741
Weighted average remaining term - vested (years)	3 years
Exercise price $12.17
Options outstanding:
Number of options (in shares)	8,500
Weighted average remaining contract life (years)	2 years 3 months
Options exercisable:
Number of options (in shares)	7,000
Weighted average remaining term - vested (years)	2 years 3 months
Exercise price $12.32
Options outstanding:
Number of options (in shares)	1,289,238
Weighted average remaining contract life (years)	2 years 3 months
Options exercisable:
Number of options (in shares)	1,023,261
Weighted average remaining term - vested (years)	2 years 3 months
Exercise price $12.37
Options outstanding:
Number of options (in shares)	457,852
Weighted average remaining contract life (years)	6 years 3 months
Options exercisable:
Number of options (in shares)	194,851
Weighted average remaining term - vested (years)	6 years 3 months
Exercise price $12.44
Options outstanding:
Number of options (in shares)	385,906
Weighted average remaining contract life (years)	4 years 3 months
Options exercisable:
Number of options (in shares)	245,720
Weighted average remaining term - vested (years)	4 years 3 months
Exercise price $13.15
Options outstanding:
Number of options (in shares)	393,497
Weighted average remaining contract life (years)	5 years 3 months
Options exercisable:
Number of options (in shares)	207,164
Weighted average remaining term - vested (years)	5 years 3 months
Exercise price $14.15
Options outstanding:
Number of options (in shares)	589,728
Weighted average remaining contract life (years)	7 years 3 months
Options exercisable:
Number of options (in shares)	191,970
Weighted average remaining term - vested (years)	7 years 3 months
Exercise price $15.57
Options outstanding:
Number of options (in shares)	718,941
Weighted average remaining contract life (years)	8 years 3 months
Options exercisable:
Number of options (in shares)	168,033
Weighted average remaining term - vested (years)	8 years 3 months
$13.49
Options outstanding:
Number of options (in shares)	5,612,812
Weighted average remaining contract life (years)	5 years 4 months 10 days
Options exercisable:
Number of options (in shares)	3,016,175
Weighted average remaining term - vested (years)	3 years 11 months 21 days
Stock options | Exercise price $7.48
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 7.48
Stock options | Exercise price $9.79
Outstanding and exercisable options
Exercise price (in dollars per share)	9.79
Stock options | Exercise price $16.59
Outstanding and exercisable options
Exercise price (in dollars per share)	11.12
Stock options | Exercise price $11.49
Outstanding and exercisable options
Exercise price (in dollars per share)	11.49
Stock options | Exercise price $11.70
Outstanding and exercisable options
Exercise price (in dollars per share)	11.70
Stock options | Exercise price $12.12
Outstanding and exercisable options
Exercise price (in dollars per share)	12.12
Stock options | Exercise price $12.17
Outstanding and exercisable options
Exercise price (in dollars per share)	$ 12.17
Stock options | Exercise price $12.32
Outstanding and exercisable options
Exercise price (in dollars per share)		$ 12.32
Stock options | Exercise price $12.37
Outstanding and exercisable options
Exercise price (in dollars per share)		12.37
Stock options | Exercise price $12.44
Outstanding and exercisable options
Exercise price (in dollars per share)		12.44
Stock options | Exercise price $13.15
Outstanding and exercisable options
Exercise price (in dollars per share)		13.15
Stock options | Exercise price $14.15
Outstanding and exercisable options
Exercise price (in dollars per share)		14.15
Stock options | Exercise price $15.57
Outstanding and exercisable options
Exercise price (in dollars per share)		15.57
Stock options | Total $13.49
Outstanding and exercisable options
Exercise price (in dollars per share)		$ 12.75

Disclosures About Fair Value _3

Disclosures About Fair Value of Financial Instruments - Carrying Amount and Estimated Fair Value of Financial Instruments (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Fair Value Disclosures [Abstract]
Significant unrealized appreciation or depreciation in financial instruments	$ 0	$ 0
Financial assets:
Securities available-for-sale	801,450,000	792,535,000
Securities held-to-maturity	22,446,000	29,667,000
Accrued interest receivable	24,490,000	23,352,000
Derivative asset	6,445,000	214,000
Financial liabilities:
Borrowed funds	234,389,000	108,238,000
Junior subordinated debentures	111,213,000	111,213,000
Derivative liability	6,445,000	1,339,000
Assets transferred between Level 1 and Level 2	0	0
Level 1
Financial assets:
Cash and cash equivalents	68,789,000	77,710,000
Securities available-for-sale	0	574,000
Securities held-to-maturity	0	0
Loans receivable, net	0	3,128,000
Accrued interest receivable	24,490,000	23,352,000
Derivative asset	0	0
FHLB Stock	0	0
Total assets	93,279,000	104,764,000
Financial liabilities:
Savings and checking accounts	6,489,338,000	6,414,366,000
Time deposits	0	0
Borrowed funds	234,389,000	108,238,000
Junior subordinated debentures	0	0
Accrued interest payable	744,000	460,000
Total financial liabilities	6,724,471,000	6,523,064,000
Level 2
Financial assets:
Cash and cash equivalents	0	0
Securities available-for-sale	801,450,000	791,961,000
Securities held-to-maturity	22,446,000	29,667,000
Loans receivable, net	0	0
Accrued interest receivable	0	0
Derivative asset	6,445,000	214,000
FHLB Stock	0	0
Total assets	830,341,000	821,842,000
Financial liabilities:
Savings and checking accounts	0	0
Time deposits	0	0
Borrowed funds	0	0
Junior subordinated debentures	0	0
Accrued interest payable	0	0
Total financial liabilities	6,445,000	1,339,000
Level 3
Financial assets:
Cash and cash equivalents	0	0
Securities available-for-sale	0	0
Securities held-to-maturity	0	0
Loans receivable, net	7,845,313,000	7,759,434,000
Accrued interest receivable	0	0
Derivative asset	0	0
FHLB Stock	0	0
Total assets	7,845,313,000	7,759,434,000
Financial liabilities:
Savings and checking accounts	0	0
Time deposits	1,434,410,000	1,433,380,000
Borrowed funds	0	0
Junior subordinated debentures	102,572,000	110,954,000
Accrued interest payable	0	0
Total financial liabilities	1,536,982,000	1,544,334,000
Carrying amount
Financial assets:
Cash and cash equivalents	68,789,000	77,710,000
Securities available-for-sale	801,450,000	792,535,000
Securities held-to-maturity	22,765,000	29,678,000
Loans receivable, net	7,996,225,000	7,736,614,000
Accrued interest receivable	24,490,000	23,352,000
Derivative asset	6,445,000	214,000
FHLB Stock	15,635,000	11,733,000
Total assets	8,935,799,000	8,671,836,000
Financial liabilities:
Savings and checking accounts	6,489,338,000	6,414,366,000
Time deposits	1,404,841,000	1,412,623,000
Borrowed funds	234,389,000	108,238,000
Junior subordinated debentures	111,213,000	111,213,000
Accrued interest payable	744,000	460,000
Total financial liabilities	8,246,970,000	8,048,239,000
Estimated fair value
Financial assets:
Cash and cash equivalents	68,789,000	77,710,000
Securities available-for-sale	801,450,000	792,535,000
Securities held-to-maturity	22,446,000	29,667,000
Loans receivable, net	7,845,313,000	7,762,562,000
Accrued interest receivable	24,490,000	23,352,000
Derivative asset	6,445,000	214,000
FHLB Stock	15,635,000	11,733,000
Total assets	8,784,568,000	8,697,773,000
Financial liabilities:
Savings and checking accounts	6,489,338,000	6,414,366,000
Time deposits	1,434,410,000	1,433,380,000
Borrowed funds	234,389,000	108,238,000
Junior subordinated debentures	102,572,000	110,954,000
Accrued interest payable	744,000	460,000
Total financial liabilities	8,267,898,000	8,068,737,000
Interest rate swaps | Level 1
Financial liabilities:
Derivative liability	0	0
Interest rate swaps | Level 2
Financial liabilities:
Derivative liability	6,445,000	1,278,000
Interest rate swaps | Level 3
Financial liabilities:
Derivative liability	0	0
Interest rate swaps | Carrying amount
Financial liabilities:
Derivative liability	6,445,000	1,278,000
Interest rate swaps | Estimated fair value
Financial liabilities:
Derivative liability	$ 6,445,000	1,278,000
Foreign exchange swaps | Level 1
Financial liabilities:
Derivative liability		0
Foreign exchange swaps | Level 2
Financial liabilities:
Derivative liability		61,000
Foreign exchange swaps | Level 3
Financial liabilities:
Derivative liability		0
Foreign exchange swaps | Carrying amount
Financial liabilities:
Derivative liability		61,000
Foreign exchange swaps | Estimated fair value
Financial liabilities:
Derivative liability		$ 61,000

Disclosures About Fair Value _4

Disclosures About Fair Value of Financial Instruments - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	$ 801,450	$ 792,535
Derivative asset	6,445	214
Cash flow hedges - interest rate swaps	6,445	1,339
Level 1
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	574
Derivative asset	0	0
Total assets	93,279	104,764
Level 2
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	801,450	791,961
Derivative asset	6,445	214
Total assets	830,341	821,842
Level 3
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	0	0
Derivative asset	0	0
Total assets	7,845,313	7,759,434
Measured on recurring basis
Assets and liabilities measured at fair value on a recurring basis
Total assets	807,895	792,749
Total liabilities	6,445	1,339
Measured on recurring basis | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Equity securities	0	574
Measured on recurring basis | Debt securities
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	224,192	261,235
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	14,780	1
Measured on recurring basis | Debt securities | Government sponsored enterprises
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	187,335	209,269
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	21,163	51,056
Measured on recurring basis | Debt securities | Corporate
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	914	909
Measured on recurring basis | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Derivative asset	6,445	214
Cash flow hedges - interest rate swaps	6,445	1,278
Measured on recurring basis | Mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	577,258	530,726
Measured on recurring basis | Residential mortgage-backed securities | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	27,041	29,695
Measured on recurring basis | Residential mortgage-backed securities | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	73,196	82,969
Measured on recurring basis | Residential mortgage-backed securities | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	51,621	64,021
Measured on recurring basis | Residential mortgage-backed securities | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	528	555
Measured on recurring basis | Collateralized mortgage obligations | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	52,331	4,769
Measured on recurring basis | Collateralized mortgage obligations | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	207,033	191,512
Measured on recurring basis | Collateralized mortgage obligations | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	165,508	157,190
Measured on recurring basis | Collateralized mortgage obligations | SBA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities		0
Measured on recurring basis | Collateralized mortgage obligations | Non-agency
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	0	15
Measured on recurring basis | Foreign exchange swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - interest rate swaps		61
Measured on recurring basis | Level 1
Assets and liabilities measured at fair value on a recurring basis
Total assets	0	574
Total liabilities	0	0
Measured on recurring basis | Level 1 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Equity securities	0	574
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 | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Derivative asset	0	0
Cash flow hedges - interest rate swaps	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
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 | Foreign exchange swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - interest rate swaps		0
Measured on recurring basis | Level 2
Assets and liabilities measured at fair value on a recurring basis
Total assets	807,895	792,175
Total liabilities	6,445	1,339
Measured on recurring basis | Level 2 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Equity securities	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	224,192	261,235
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	14,780	1
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	187,335	209,269
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	21,163	51,056
Measured on recurring basis | Level 2 | Debt securities | Corporate
Assets and liabilities measured at fair value on a recurring basis
Securities available-for-sale	914	909
Measured on recurring basis | Level 2 | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Derivative asset	6,445	214
Cash flow hedges - interest rate swaps	6,445	1,278
Measured on recurring basis | Level 2 | Mortgage-backed securities
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	577,258	530,726
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	27,041	29,695
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	73,196	82,969
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	51,621	64,021
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	528	555
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | GNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	52,331	4,769
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | FNMA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	207,033	191,512
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | FHLMC
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities	165,508	157,190
Measured on recurring basis | Level 2 | Collateralized mortgage obligations | SBA
Assets and liabilities measured at fair value on a recurring basis
Mortgage-backed securities		0
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	0	15
Measured on recurring basis | Level 2 | Foreign exchange swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - interest rate swaps		61
Measured on recurring basis | Level 3
Assets and liabilities measured at fair value on a recurring basis
Total assets	0	0
Total liabilities	0	0
Measured on recurring basis | Level 3 | Equity securities
Assets and liabilities measured at fair value on a recurring basis
Equity securities	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	0	0
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	0	0
Measured on recurring basis | Level 3 | Interest rate swaps
Assets and liabilities measured at fair value on a recurring basis
Derivative asset	0	0
Cash flow hedges - interest rate swaps	0	0
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
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 | Foreign exchange swaps
Assets and liabilities measured at fair value on a recurring basis
Cash flow hedges - interest rate swaps		$ 0

Disclosures About Fair Value _5

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, 2018	Dec. 31, 2017
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	$ 0	$ 9,366
Total net realized investment gains and net change in unrealized appreciation:
Included in net income as OTTI	0	0
Included in other comprehensive income	0	1,282
Purchases	0	0
Sales		(10,648)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Balance at the end of the period	$ 0	$ 0

Disclosures About Fair Value _6

Disclosures About Fair Value of Financial Instruments - Nonrecurring Assets that had Fair Market Values Below the Carrying Amount (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	$ 93,279	$ 104,764
Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	830,341	821,842
Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	7,845,313	7,759,434
Loans evaluated for impairment
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	40,333
Real estate owned
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	2,498
Fair Value, Measurements, Nonrecurring
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	42,831	39,087
Fair Value, Measurements, Nonrecurring | Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	0	0
Fair Value, Measurements, Nonrecurring | Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	0	0
Fair Value, Measurements, Nonrecurring | Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	42,831	39,087
Fair Value, Measurements, Nonrecurring | Loans evaluated for impairment
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	40,333	33,421
Fair Value, Measurements, Nonrecurring | Loans evaluated for impairment | Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	0	0
Fair Value, Measurements, Nonrecurring | Loans evaluated for impairment | Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	0	0
Fair Value, Measurements, Nonrecurring | Loans evaluated for impairment | Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	40,333	33,421
Fair Value, Measurements, Nonrecurring | Real estate owned
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	2,498	5,666
Fair Value, Measurements, Nonrecurring | Real estate owned | Level 1
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	0	0
Fair Value, Measurements, Nonrecurring | Real estate owned | Level 2
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	0	0
Fair Value, Measurements, Nonrecurring | Real estate owned | Level 3
Fair value measurement for nonrecurring assets that had a fair market value below the carrying amount
Fair value	$ 2,498	$ 5,666

Disclosures About Fair Value _7

Disclosures About Fair Value of Financial Instruments - Additional Quantitative Information, Assets Measured at Fair Value, Recurring and Nonrecurring Basis, Level 3 Input (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2018USD ($)
Loans evaluated for impairment
Quantitative information for Level 3 Fair Value Measurements Assets
Fair value	$ 40,333
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	$ 2,498
Real estate owned | Appraisal Value
Quantitative information for Level 3 Fair Value Measurements Assets
Estimated costs to sell	10.00%
Measurement Input, Discount Rate | Loans evaluated for impairment | Discounted Cash Flow | Minimum
Quantitative information for Level 3 Fair Value Measurements Assets
Discount rate	0.0425
Measurement Input, Discount Rate | Loans evaluated for impairment | Discounted Cash Flow | Maximum
Quantitative information for Level 3 Fair Value Measurements Assets
Discount rate	0.100
Measurement Input, Discount Rate | Loans evaluated for impairment | Discounted Cash Flow | Weighted Average
Quantitative information for Level 3 Fair Value Measurements Assets
Discount rate	0.0750

Regulatory Capital Requiremen_3

Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Tier 1 capital (leverage) (to average assets)
Minimum capital requirements (as a percent)	1.875%	1.25%
Northwest Bank
Total capital (to risk weighted assets)
Actual amount	$ 1,026,027	$ 1,017,251
Actual ratio (as a percent)	13.736%	14.189%
Capital required for capital adequacy	$ 737,647	$ 663,179
Minimum capital requirements ratio (as a percent)	9.875%	9.25%
Well capitalized requirements amount	$ 746,984	$ 716,951
Well capitalized requirements ratio (as a percent)	10.00%	10.00%
Tier 1 capital (to risk weighted assets)
Actual amount	$ 970,813	$ 960,443
Actual ratio (as a percent)	12.996%	13.396%
Minimum capital requirements amount	$ 588,250	$ 519,789
Minimum capital requirements ratio (as a percent)	7.875%	7.25%
Well capitalized requirements amount	$ 597,587	$ 573,560
Well capitalized requirements ratio (as a percent)	8.00%	8.00%
CET 1 capital (to risk weighted assets)
Actual amount	$ 970,813	$ 960,443
Actual ratio (as a percent)	12.996%	13.396%
Minimum capital requirements amount	$ 476,202	$ 412,247
Minimum capital requirements ratio (as a percent)	6.375%	5.75%
Well capitalized requirements amount	$ 448,190	$ 430,170
Well capitalized requirements ratio (as a percent)	6.00%	6.00%
Tier 1 capital (leverage) (to average assets)
Actual amount	$ 970,813	$ 960,443
Actual ratio (as a percent)	10.24%	10.40%
Minimum capital requirements amount	$ 379,236	$ 369,482
Minimum capital requirements ratio (as a percent)	4.00%	4.00%
Well capitalized requirements amount	$ 474,045	$ 461,853
Well capitalized requirements ratio (as a percent)	5.00%	5.00%
Northwest Bancshares, Inc.
Total capital (to risk weighted assets)
Actual amount	$ 1,183,619	$ 1,136,076
Actual ratio (as a percent)	15.833%	15.831%
Capital required for capital adequacy	$ 738,212	$ 663,823
Minimum capital requirements ratio (as a percent)	9.875%	9.25%
Well capitalized requirements amount	$ 747,557	$ 71,747
Well capitalized requirements ratio (as a percent)	10.00%	10.00%
Tier 1 capital (to risk weighted assets)
Actual amount	$ 1,128,405	$ 1,079,270
Actual ratio (as a percent)	15.095%	15.039%
Minimum capital requirements amount	$ 588,701	$ 520,294
Minimum capital requirements ratio (as a percent)	7.875%	7.25%
Well capitalized requirements amount	$ 598,045	$ 574,117
Well capitalized requirements ratio (as a percent)	8.00%	8.00%
CET 1 capital (to risk weighted assets)
Actual amount	$ 1,020,530	$ 971,395
Actual ratio (as a percent)	13.652%	13.536%
Minimum capital requirements amount	$ 476,567	$ 412,647
Minimum capital requirements ratio (as a percent)	6.375%	5.75%
Well capitalized requirements amount	$ 485,912	$ 466,470
Well capitalized requirements ratio (as a percent)	6.50%	6.50%
Tier 1 capital (leverage) (to average assets)
Actual amount	$ 1,128,405	$ 1,079,270
Actual ratio (as a percent)	11.899%	11.676%
Minimum capital requirements amount	$ 379,342	$ 369,735
Minimum capital requirements ratio (as a percent)	4.00%	4.00%
Well capitalized requirements amount	$ 474,177	$ 462,169
Well capitalized requirements ratio (as a percent)	5.00%	5.00%

Components of Accumulated Oth_3

Components of Accumulated Other Comprehensive Income - (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	$ 1,257,638	$ 1,207,724	$ 1,170,663	$ 1,163,163
Unrealized gain on marketable securities available-for-sale
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	(6,832)	(4,409)	395	3,325
Fair value of interest rate swaps
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	0	(691)	(1,778)	(2,779)
Defined benefit pension plans
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	(32,864)	(26,980)	(26,608)	(25,081)
Accumulated other comprehensive income
Accumulated other comprehensive income (net of tax)
Shareholders’ equity	$ (39,696)	$ (32,080)	$ (27,991)	$ (24,535)

Components of Accumulated Oth_4

Components of Accumulated Other Comprehensive Income - Changes in Accumulated Other Comprehensive Income by Component (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated other comprehensive income (net of tax)
Reclassification due to adoption of ASU No. 2018-02	$ (6,746)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	1,207,724	$ 1,170,663	$ 1,163,163
Other comprehensive income/(loss) before reclassification adjustments	(1,618)
Amounts reclassified from accumulated other comprehensive income	748
Net other comprehensive income/(loss)	(7,616)
Other comprehensive loss	(870)	(4,089)	(3,456)
Balance at end of the period	1,257,638	1,207,724	1,170,663
Reclassification adjustment for gains (losses) on securities, net of tax	155	2,326	202
Income tax (expense) benefit related to (gain) loss on securities	(60)	(1,488)	(129)
Amortization of prior service cost (compensation and employee benefits)	903	882	872
Income tax expense (benefit) related to compensation and employee benefits	746	613	606
Unrealized gain on marketable securities available-for-sale
Accumulated other comprehensive income (net of tax)
Reclassification due to adoption of ASU No. 2018-02	(991)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(4,409)	395	3,325
Other comprehensive income/(loss) before reclassification adjustments	(1,277)	(2,478)	(2,728)
Amounts reclassified from accumulated other comprehensive income	(155)	(2,326)	(202)
Net other comprehensive income/(loss)	(2,423)
Other comprehensive loss		(4,804)	(2,930)
Balance at end of the period	(6,832)	(4,409)	395
Reclassification adjustment for gains (losses) on securities, net of tax	215	3,814	(331)
Income tax (expense) benefit related to (gain) loss on securities	(60)	1,488	(129)
Fair value of interest rate swaps
Accumulated other comprehensive income (net of tax)
Reclassification due to adoption of ASU No. 2018-02	(149)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(691)	(1,778)	(2,779)
Other comprehensive income/(loss) before reclassification adjustments	840	1,087	1,001
Amounts reclassified from accumulated other comprehensive income	0	0	0
Net other comprehensive income/(loss)	691
Other comprehensive loss		1,087	1,001
Balance at end of the period	0	(691)	(1,778)
Defined benefit pension plans
Accumulated other comprehensive income (net of tax)
Reclassification due to adoption of ASU No. 2018-02	(5,606)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(26,980)	(26,608)	(25,081)
Other comprehensive income/(loss) before reclassification adjustments	(1,181)	(1,254)	(2,399)
Amounts reclassified from accumulated other comprehensive income	903	882	872
Net other comprehensive income/(loss)	(5,884)
Other comprehensive loss		(372)	(1,527)
Balance at end of the period	(32,864)	(26,980)	(26,608)
Amortization of prior service cost (compensation and employee benefits)	2,323	2,323	2,323
Amortization of net loss (compensation and employee benefits)	(3,568)	(3,818)	(3,801)
Income tax expense (benefit) related to compensation and employee benefits	361	613	606
Accumulated other comprehensive income
Accumulated other comprehensive income (net of tax)
Reclassification due to adoption of ASU No. 2018-02	(6,746)
Changes in accumulated other comprehensive income by component
Balance at beginning of the period	(32,080)	(27,991)	(24,535)
Other comprehensive income/(loss) before reclassification adjustments		(2,645)	(4,126)
Amounts reclassified from accumulated other comprehensive income		(1,444)	670
Other comprehensive loss	(870)	(4,089)	(3,456)
Balance at end of the period	$ (39,696)	$ (32,080)	$ (27,991)

Parent Company Only Financial_3

Parent Company Only Financial Statements - Condensed - Statements of Financial Condition (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 68,789	$ 77,710	$ 389,867	$ 167,408
Marketable securities available-for-sale (amortized cost of $811,015 and $800,094)	801,450	792,535
Other assets	34,211	30,066
Total assets	9,607,773	9,363,934
Liabilities:
Debentures payable	111,213	111,213
Other liabilities	66,312	68,485
Total liabilities	8,350,135	8,156,210
Shareholders’ equity	1,257,638	1,207,724	1,170,663	1,163,163
Total liabilities and shareholders’ equity	9,607,773	9,363,934
Parent Company
Assets
Cash and cash equivalents	155,524	26,088	$ 34,521	$ 91,056
Marketable securities available-for-sale (amortized cost of $811,015 and $800,094)	0	545
Investment in bank subsidiary	1,211,258	1,200,799
Other assets	2,298	92,712
Total assets	1,369,080	1,320,144
Liabilities:
Debentures payable	111,213	111,213
Other liabilities	230	1,207
Total liabilities	111,443	112,420
Shareholders’ equity	1,257,637	1,207,724
Total liabilities and shareholders’ equity	$ 1,369,080	$ 1,320,144

Parent Company Only Financial_4

Parent Company Only Financial Statements - Condensed - Statements of Income (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income:
Interest income	$ 97,768	$ 95,605	$ 92,875	$ 89,533	$ 91,561	$ 90,231	$ 89,797	$ 87,267	$ 90,033	$ 84,748	$ 85,555	$ 85,298	$ 375,781	$ 358,856	$ 345,634
Expense:
Other expense													11,333	10,562	11,346
Interest expense	10,937	9,788	8,649	7,766	7,321	6,994	7,066	6,690	7,091	7,454	10,008	13,746	37,140	28,071	38,299
Income before income taxes	34,014	34,775	33,199	31,925	28,724	36,005	45,384	25,798	36,855	18,894	(10,499)	26,065	133,913	135,911	71,315
Federal and state income taxes	7,547	7,035	6,900	6,940	6,576	12,414	14,402	8,052	12,361	4,697	(3,491)	8,081	28,422	41,444	21,648
Net income	$ 26,467	$ 27,740	$ 26,299	$ 24,985	$ 22,148	$ 23,591	$ 30,982	$ 17,746	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	105,491	94,467	49,667
Parent Company
Income:
Interest income													198	137	737
Other income													752	2,297	709
Dividends from bank subsidiary													105,000	90,000	50,000
Undistributed earnings from equity investment in bank subsidiary													5,149	7,255	2,760
Total income													111,099	99,689	54,206
Expense:
Compensation and benefits													1,225	1,282	1,129
Other expense													660	553	561
Interest expense													4,961	4,666	4,560
Total expense													6,846	6,501	6,250
Income before income taxes													104,253	93,188	47,956
Federal and state income taxes													(1,238)	(1,279)	(1,711)
Net income													$ 105,491	$ 94,467	$ 49,667

Parent Company Only Financial_5

Parent Company Only Financial Statements - Condensed - Statements of Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Net Income	$ 26,467	$ 27,740	$ 26,299	$ 24,985	$ 22,148	$ 23,591	$ 30,982	$ 17,746	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 105,491	$ 94,467	$ 49,667
Adjustments to reconcile net income to net cash provided by operating activities:
Noncash stock benefit plan compensation expense													7,023	4,894	10,916
Gain on sale of marketable securities													(157)	(1,148)	(625)
Net cash provided by operating activities													138,909	151,798	135,712
Investing activities:
Net (Purchase)/sale of marketable securities													5,206	36,811	1,951
Net cash provided by/(used in) investing activities													(281,913)	(104,040)	1,150,598
Financing activities:
Cash dividends paid													(69,921)	(65,212)	(60,156)
Share repurchases													0	0	(1,752)
Excess tax benefit from stock-based compensation													0	0	1,425
Proceeds from options exercised													8,190	7,001	10,856
Net cash provided by/(used) in financing activities													134,083	(359,915)	(1,063,851)
Net increase/(decrease) in cash and cash equivalents													(8,921)	(312,157)	222,459
Cash and cash equivalents at beginning of period				77,710				389,867				167,408	77,710	389,867	167,408
Cash and cash equivalents at end of period	68,789				77,710				389,867				68,789	77,710	389,867
Parent Company
Operating activities:
Net Income													105,491	94,467	49,667
Adjustments to reconcile net income to net cash provided by operating activities:
Undistributed earnings of subsidiary													(5,149)	(7,255)	(2,760)
Noncash stock benefit plan compensation expense													0	4,894	10,916
Gain on sale of marketable securities													(146)	(1,615)	(43)
Net change in other assets and liabilities													91,520	(43,513)	(63,533)
Net cash provided by operating activities													191,716	46,978	(5,753)
Investing activities:
Net (Purchase)/sale of marketable securities													(550)	2,800	(1,952)
Net cash provided by/(used in) investing activities													(550)	2,800	(1,952)
Financing activities:
Cash dividends paid													(69,921)	(65,212)	(60,156)
Share repurchases													0	0	(1,752)
Repayment of loan to ESOP													0	0	797
Excess tax benefit from stock-based compensation													0	0	1,425
Proceeds from options exercised													8,191	7,001	10,856
Net cash provided by/(used) in financing activities													(61,730)	(58,211)	(48,830)
Net increase/(decrease) in cash and cash equivalents													129,436	(8,433)	(56,535)
Cash and cash equivalents at beginning of period				$ 26,088				$ 34,521				$ 91,056	26,088	34,521	91,056
Cash and cash equivalents at end of period	$ 155,524				$ 26,088				$ 34,521				$ 155,524	$ 26,088	$ 34,521

Derivative Financial Instrume_3

Derivative Financial Instruments - Narrative (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Fair value of swap agreements	$ 6,445	$ 1,339
Cash flow hedges | Interest rate swaps
Derivative [Line Items]
Notional amount	50,000
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Fair value of swap agreements	$ 0	$ 1,064

Derivative Financial Instrume_4

Derivative Financial Instruments - Schedule of Derivative Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Derivative asset, notional amount	$ 221,919	$ 92,631
Derivative asset	6,445	214
Derivative liability, notional amount	221,919	154,975
Cash flow hedges - interest rate swaps	6,445	1,339
Derivatives designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	0	0
Derivative asset	0	0
Derivative liability, notional amount	0	50,000
Cash flow hedges - interest rate swaps	0	1,064
Derivatives not designated as hedging instruments: | Interest rate swaps
Derivative [Line Items]
Derivative asset, notional amount	221,919	92,631
Derivative asset	6,445	214
Derivative liability, notional amount	221,919	92,631
Cash flow hedges - interest rate swaps	6,445	214
Derivatives not designated as hedging instruments: | Foreign exchange swaps
Derivative [Line Items]
Derivative asset, notional amount	0	0
Derivative asset	0	0
Derivative liability, notional amount	0	12,344
Cash flow hedges - interest rate swaps	$ 0	$ 61

Derivative Financial Instrume_5

Derivative Financial Instruments - Gain (Loss) on Derivative Instruments (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Gain (loss) on non-hedging swap derivatives	$ (288)	$ (373)	$ 0
Gain (loss) on hedging interest rate derivatives	$ 949	$ 1,599	$ 1,866

Selected Quarterly Financial _3

Selected Quarterly Financial Data - Unaudited (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended												12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Interest income	$ 97,768	$ 95,605	$ 92,875	$ 89,533	$ 91,561	$ 90,231	$ 89,797	$ 87,267	$ 90,033	$ 84,748	$ 85,555	$ 85,298	$ 375,781	$ 358,856	$ 345,634
Interest expense	10,937	9,788	8,649	7,766	7,321	6,994	7,066	6,690	7,091	7,454	10,008	13,746	37,140	28,071	38,299
Net interest income	86,831	85,817	84,226	81,767	84,240	83,237	82,731	80,577	82,942	77,294	75,547	71,552	338,641	330,785	307,335
Provision for loan losses	3,792	6,982	5,349	4,209	6,525	3,027	5,562	4,637	2,145	5,538	4,199	1,660	20,332	19,751	13,542
Noninterest income	23,248	22,557	24,109	21,788	22,905	24,594	41,477	21,504	24,819	20,818	20,275	19,448	91,702	110,480	85,360
Noninterest expenses	72,273	66,617	69,787	67,421	71,896	68,799	73,262	71,646	68,761	73,680	102,122	63,275	276,098	285,603	307,838
Income before income taxes	34,014	34,775	33,199	31,925	28,724	36,005	45,384	25,798	36,855	18,894	(10,499)	26,065	133,913	135,911	71,315
Income tax expense/ (benefit)	7,547	7,035	6,900	6,940	6,576	12,414	14,402	8,052	12,361	4,697	(3,491)	8,081	28,422	41,444	21,648
Net income	$ 26,467	$ 27,740	$ 26,299	$ 24,985	$ 22,148	$ 23,591	$ 30,982	$ 17,746	$ 24,494	$ 14,197	$ (7,008)	$ 17,984	$ 105,491	$ 94,467	$ 49,667
Basic earnings per share (in dollars per share)	$ 0.26	$ 0.27	$ 0.26	$ 0.25	$ 0.22	$ 0.23	$ 0.31	$ 0.18	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 1.03	$ 0.94	$ 0.50
Diluted earnings per share (in dollars per share)	$ 0.26	$ 0.27	$ 0.25	$ 0.24	$ 0.22	$ 0.23	$ 0.30	$ 0.17	$ 0.24	$ 0.14	$ (0.07)	$ 0.18	$ 1.02	$ 0.92	$ 0.49