XML 16 R46.htm IDEA: XBRL DOCUMENT v2.4.1.9
Loans receivable (Details 6) (USD $)
In Thousands, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment $ 5,978,400us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment $ 5,898,759us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
Loans individually evaluated for impairment 86,464us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment 91,132us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
Loans individually evaluated for impairment for which there is a related impairment reserve 60,252nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved 63,659nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
Related impairment reserve 7,326us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1 8,930us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
Loans individually evaluated for impairment for which there is no related impairment reserve 26,212nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved 27,473nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
Personal Banking    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 3,829,676us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 3,820,479us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment 9,889us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 9,852us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 9,889nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 9,852nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Related impairment reserve 1,361us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 1,363us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Personal Banking | Residential mortgage loans    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 2,536,741us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 2,514,060us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment 7,129us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 7,396us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 7,129nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 7,396nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Related impairment reserve 1,140us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 1,116us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ResidentialMortgageMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Personal Banking | Home equity loans    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 1,053,073us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 1,063,741us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment 2,666us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 2,390us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 2,666nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 2,390nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Related impairment reserve 220us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 246us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_HomeEquityMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Personal Banking | Other consumer loans    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 239,862us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 242,678us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment 94us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 66us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 94nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 66nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Related impairment reserve 1us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember		 1us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_ConsumerLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_PersonalBankingMember
Business Banking    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 2,148,724us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 2,078,280us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment 76,575us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 81,280us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 50,363nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 53,807nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Related impairment reserve 5,965us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 7,567us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment for which there is no related impairment reserve 26,212nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 27,473nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Business Banking | Commercial real estate loans    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 1,791,047us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 1,734,864us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment 65,527us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 66,320us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 42,972nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 42,869nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Related impairment reserve 5,223us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 6,189us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment for which there is no related impairment reserve 22,555nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 23,451nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialRealEstateMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Business Banking | Commercial loans    
Evaluation of impaired loans by portfolio segment and by class of financing receivable    
Loans collectively evaluated for impairment 357,677us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 343,416us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment 11,048us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 14,960us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment for which there is a related impairment reserve 7,391nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 10,938nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Related impairment reserve 742us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 1,378us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember
Loans individually evaluated for impairment for which there is no related impairment reserve $ 3,657nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember		 $ 4,022nwbi_FinancingReceivableIndividuallyEvaluatedForImpairmentNotReserved
/ us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis
= us-gaap_CommercialLoanMember
/ us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis
= nwbi_BusinessBankingMember