Defined benefit plan effective date of freezing and termination.

No definition available.

Name:	pcsb_DefinedBenefitPlanEffectiveDateOfFreezingAndTermination
Namespace Prefix:	pcsb_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee stock ownership plan ESOP payable term.

+ References

No definition available.

+ Details

Name:	pcsb_EmployeeStockOwnershipPlanEsopPayableTerm
Namespace Prefix:	pcsb_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Employee stock ownership plan ESOP prime rate percentage.

+ References

No definition available.

+ Details

Name:	pcsb_EmployeeStockOwnershipPlanEsopPrimeRatePercentage
Namespace Prefix:	pcsb_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_CompensationAndRetirementDisclosureAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of contribution received by defined benefit plan from employer which increases plan assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 55
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-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
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-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount of plan compensation cost recognized during the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The amount reported as a liability as of the balance sheet date by the entity (the employer) of the loan made by a third-party lender directly to the ESOP.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 40
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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Sum of the allocated, committed-to-be-released and suspense shares of the entity held by the plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 40
-Section 50
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+ Details

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Namespace Prefix:	us-gaap_
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Balance Type:	na
Period Type:	instant

- Definition

Number of committed-to-be-released shares held by the Employee Stock Option Plan at balance sheet date. Committed-to-be-released shares are shares that will be released in the future and will be allocated to employees for services rendered in an accounting period. These shares are legally released from suspense and from serving as collateral for ESOP debt as a result of payment of debt service.

+ References

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-SubTopic 40
-Section 50
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Balance Type:	na
Period Type:	instant

- Definition

Per share or per unit amount of equity securities issued.

+ References

No definition available.

+ Details

Name:	us-gaap_SharesIssuedPricePerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
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Post-Retirement Benefits - Additional Information (Detail) - USD ($)		3 Months Ended		9 Months Ended
	Apr. 20, 2017	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Jun. 30, 2019
Compensation And Retirement Disclosure [Abstract]
Effective date of freezing of the defined benefit pension plan				May 01, 2017
Defined benefit plan, contributions by employer		$ 0		$ 0
ESOP shares	1,453,209	1,443,063		1,443,063		1,445,469
Stock price	$ 10.00
ESOP payable term	15 years
ESOP prime rate percentage				4.75%
ESOP borrowing		$ 11,600,000		$ 11,600,000
Number of shares committed to be released per year through 2032		96,881		96,881
ESOP Compensation		$ 438,000	$ 464,000	$ 1,415,000	$ 1,434,000