Note 18 - Fair Value and Interest Rate Risk - Carrying Amounts and Estimated Fair Values of Financial Instruments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Available-for-sale securities	$ 24,428	$ 29,377
Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities	10,441	13,413
Corporate Debt Securities [Member]
Available-for-sale securities	8,961	9,010
US Government Agencies Debt Securities [Member]
Available-for-sale securities		4,954
Subordinated Notes [Member]
Available-for-sale securities	5,026	2,000
Reported Value Measurement [Member]
Financial assets, total	708,593	609,009
Financial liabilities, total	688,918	587,223
Financial assets, net	19,675	21,786
Estimate of Fair Value Measurement [Member]
Financial assets, total	708,368	608,042
Financial liabilities, total	687,463	586,383
Financial assets, net	20,905	21,659
Fair Value, Inputs, Level 1 [Member] \| Reported Value Measurement [Member] \| Brokered Deposits [Member]
Deposits	63,932	48,154
Fair Value, Inputs, Level 1 [Member] \| Reported Value Measurement [Member] \| Cash and Due from Banks [Member]
Cash and cash equivalents	2,596	2,588
Fair Value, Inputs, Level 1 [Member] \| Reported Value Measurement [Member] \| Interest-bearing Deposits [Member]
Cash and cash equivalents	89,693	82,812
Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value Measurement [Member] \| Brokered Deposits [Member]
Deposits	63,897	48,062
Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value Measurement [Member] \| Cash and Due from Banks [Member]
Cash and cash equivalents	2,596	2,588
Fair Value, Inputs, Level 1 [Member] \| Estimate of Fair Value Measurement [Member] \| Interest-bearing Deposits [Member]
Cash and cash equivalents	89,693	82,812
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member]
Other investments	4,450	4,450
Federal Reserve Bank stock	2,109	2,075
Federal Home Loan Bank stock	5,609	6,570
Accrued interest receivable	2,726	2,010
FHLB and correspondent bank borrowings	138,000	132,000
Senior notes	11,628
Subordinated debentures	8,079	8,072
Accrued interest payable	118	532
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Demand Deposits [Member]
Deposits	76,772	85,797
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Savings Deposits [Member]
Deposits	131,429	106,291
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Money Market Deposits [Member]
Deposits	15,593	19,508
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Negotiable Order of Withdrawal (NOW) Accounts [Member]
Deposits	29,912	27,951
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Time Deposits [Member]
Deposits	211,686	156,964
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities	10,441	13,413
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities	8,961	9,010
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| US Government Agencies Debt Securities [Member]
Available-for-sale securities		4,954
Fair Value, Inputs, Level 2 [Member] \| Reported Value Measurement [Member] \| Subordinated Notes [Member]
Available-for-sale securities	3,026	2,000
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member]
Other investments	4,450	4,450
Federal Reserve Bank stock	2,109	2,075
Federal Home Loan Bank stock	5,609	6,570
Accrued interest receivable	2,726	2,010
FHLB and correspondent bank borrowings	138,149	131,903
Senior notes	11,628
Subordinated debentures	8,079	8,072
Accrued interest payable	118	532
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Demand Deposits [Member]
Deposits	76,772	85,797
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Savings Deposits [Member]
Deposits	131,429	106,291
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Money Market Deposits [Member]
Deposits	15,593	19,508
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Negotiable Order of Withdrawal (NOW) Accounts [Member]
Deposits	29,912	27,951
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Time Deposits [Member]
Deposits	210,321	156,363
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Mortgage-backed Securities, Issued by US Government Sponsored Enterprises [Member]
Available-for-sale securities	10,441	13,413
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Corporate Debt Securities [Member]
Available-for-sale securities	8,961	9,010
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| US Government Agencies Debt Securities [Member]
Available-for-sale securities		4,954
Fair Value, Inputs, Level 2 [Member] \| Estimate of Fair Value Measurement [Member] \| Subordinated Notes [Member]
Available-for-sale securities	3,026	2,000
Fair Value, Inputs, Level 3 [Member] \| Reported Value Measurement [Member]
Loans receivable, net	576,982	479,127
Note payable	1,769	1,954
Fair Value, Inputs, Level 3 [Member] \| Reported Value Measurement [Member] \| Subordinated Notes [Member]
Available-for-sale securities	2,000
Fair Value, Inputs, Level 3 [Member] \| Estimate of Fair Value Measurement [Member]
Loans receivable, net	576,757	478,160
Note payable	1,565	1,904
Fair Value, Inputs, Level 3 [Member] \| Estimate of Fair Value Measurement [Member] \| Subordinated Notes [Member]
Available-for-sale securities	$ 2,000

Fair value portion of the Federal Reserve Bank Stock.

No definition available.

Name:	pnbk_FederalReserveBankStockFairValueDisclosure
Namespace Prefix:	pnbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of interest receivable.

+ References

No definition available.

+ Details

Name:	pnbk_InterestReceivableFairValueDisclosure
Namespace Prefix:	pnbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of investments classified as other.

+ References

No definition available.

+ Details

Name:	pnbk_OtherInvestmentsFairValueDisclosure
Namespace Prefix:	pnbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of senior notes.

+ References

No definition available.

+ Details

Name:	pnbk_SeniorNotesFairValueDisclosure
Namespace Prefix:	pnbk_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of accrued expenses.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_AccruedLiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

+ References

+ Details

Name:	us-gaap_AssetsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 25
-Paragraph 1
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=65884222&loc=d3e22054-111558

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (aa)
-URI http://asc.fasb.org/extlink&oid=73527792&loc=d3e27232-111563

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=66010992&loc=d3e26610-111562

+ Details

Name:	us-gaap_AvailableForSaleSecurities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of currency on hand as well as demand deposits with banks or financial institutions. Includes other kinds of accounts that have the general characteristics of demand deposits. Also includes short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash
-URI http://asc.fasb.org/extlink&oid=6506951

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Cash Equivalents
-URI http://asc.fasb.org/extlink&oid=6507016

+ Details

Name:	us-gaap_CashAndCashEquivalentsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of deposit liabilities held by the entity, including, but not limited to, foreign and domestic, interest and noninterest bearing, demand deposits, saving deposits, negotiable orders of withdrawal (NOW) and time deposits.

+ References

No definition available.

+ Details

Name:	us-gaap_DepositsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of subordinated debt obligations including, but not limited to, subordinated loan, subordinated bond, subordinated debenture or junior debt.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66048111&loc=d3e19207-110258

+ Details

Name:	us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of asset after deduction of liability.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueNetAssetLiability
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of borrowing from Federal Home Loan Bank (FHLBank).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03.13(3)(a))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

Name:	us-gaap_FederalHomeLoanBankBorrowingsFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value of financial obligations, including, but not limited to, debt instruments, derivative liabilities, federal funds purchased and sold under agreements to repurchase, securities loaned or sold under agreements to repurchase, financial instruments sold not yet purchased, guarantees, line of credit, loans and notes payable, servicing liability, and trading liabilities.

+ References

No definition available.

+ Details

Name:	us-gaap_FinancialLiabilitiesFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Fair value portion of investments in Federal Home Loan Bank (FHLBank) stock.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 325
-SubTopic 20
-Section 25
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=29638263&loc=d3e39828-111592

+ Details

Name:	us-gaap_InvestmentInFederalHomeLoanBankStockFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of loan receivable, including, but not limited to, mortgage loans held for investment, finance receivables held for investment, policy loans on insurance contracts.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Glossary Loan
-URI http://asc.fasb.org/extlink&oid=6517073

+ Details

Name:	us-gaap_LoansReceivableFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Fair value portion of notes payable.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.19,20,22)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_NotesPayableFairValueDisclosure
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=us-gaap_USGovernmentAgenciesDebtSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis=pnbk_SubordinatedNotesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_CarryingReportedAmountFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByMeasurementBasisAxis=us-gaap_EstimateOfFairValueFairValueDisclosureMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=pnbk_BrokeredDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=pnbk_CashAndDueFromBanksMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CashAndCashEquivalentsAxis=us-gaap_InterestBearingDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=pnbk_DemandDeposits1Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=pnbk_SavingsDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=pnbk_MoneyMarketDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=pnbk_NegotiableOrderOfWithdrawalNowAccountsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByLiabilityClassAxis=pnbk_TimeDepositsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: