REGULATORY CAPITAL (Schedule of Regulatory Capital Amounts and Ratios) (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
The Bank [Member]
Total Capital
Total Capital (to risk-weighted assets)	$ 672,614	$ 600,478
Total Capital (to risk-weighted assets) ratio	14.05	14.81
Minimum Capital required to be well-capitalized	$ 478,628	$ 405,587
Minimum Capital required to be well-capitalized, ratio	10.00	10.00
Minimum amount of capital for adequacy purposes	$ 382,902	$ 324,469
Minimum amount of capital for adequacy purposes, ratio	8.00	8.00
Tier I Capital (to risk-weighted assets)
Tier 1 Capital (to risk-weighted assets)	$ 612,762	$ 549,575
Tier 1 Capital (to risk-weighted assets) ratio	12.80	13.55
Minimum Tier 1 Capital required to be well-capitalized	$ 382,902	$ 324,469
Minimum Tier 1 Capital required to be well-capitalized, ratio	8.00	8.00
Minimum amount of Tier 1 Capital for adequacy purposes	$ 287,177	$ 243,352
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	6.00	6.00
Common equity tier I
Common equity tier 1 (to risk-weighted assets)	$ 612,738	$ 549,540
Common equity tier I (to risk-weighted assets) ratio	12.80	13.55
Minimum Common equity tier I required to be well-capitalized	$ 311,108	$ 263,631
Minimum common equity tier I required to be well-capitalized, ratio	6.50%	6.50%
Minimum amount of common equity tier I for adequacy purposes	$ 215,382	$ 182,514
Minimum amount of common equity tier I for adequacy purposes, ratio	4.50%	4.50%
Tier I Leverage Capital (to average assets)
Tier 1 Capital(to average assets)	$ 612,762	$ 549,575
Tier 1 Capital (to average assets) ratio	9.99	9.71
Minimum Tier 1 Capital required to be well-capitalized	$ 306,538	$ 283,083
Minimum Tier 1 Capital required to be well-capitalized, ratio	5.00	5.00
Minimum amount of Tier 1 Capital for adequacy purposes	$ 245,231	$ 226,466
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	4.00	4.00
The Bank [Member] \| Conservation Buffer [Member]
Total Capital
Minimum amount of capital for adequacy purposes	$ 502,559	$ 425,866
Minimum amount of capital for adequacy purposes, ratio	10.50	10.50
Tier I Capital (to risk-weighted assets)
Minimum amount of Tier 1 Capital for adequacy purposes	$ 406,834	$ 344,749
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	8.50	8.50
Common equity tier I
Minimum amount of common equity tier I for adequacy purposes	$ 335,039	$ 283,911
Minimum amount of common equity tier I for adequacy purposes, ratio	7.00%	7.00%
Tier I Leverage Capital (to average assets)
Minimum amount of Tier 1 Capital for adequacy purposes	$ 245,231	$ 226,466
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	4.00	4.00
Parent Company [Member]
Total Capital
Total Capital (to risk-weighted assets)	$ 700,790	$ 716,210
Total Capital (to risk-weighted assets) ratio	14.64	17.67
Minimum amount of capital for adequacy purposes	$ 382,944	$ 324,322
Minimum amount of capital for adequacy purposes, ratio	8.00	8.00
Tier I Capital (to risk-weighted assets)
Tier 1 Capital (to risk-weighted assets)	$ 508,231	$ 483,535
Tier 1 Capital (to risk-weighted assets) ratio	10.62	11.93
Minimum amount of Tier 1 Capital for adequacy purposes	$ 287,208	$ 243,242
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	6.00	6.00
Common equity tier I
Common equity tier 1 (to risk-weighted assets)	$ 508,207	$ 483,500
Common equity tier I (to risk-weighted assets) ratio	10.62	11.93
Minimum amount of common equity tier I for adequacy purposes	$ 215,406	$ 182,431
Minimum amount of common equity tier I for adequacy purposes, ratio	4.50%	4.50%
Tier I Leverage Capital (to average assets)
Tier 1 Capital(to average assets)	$ 508,231	$ 483,535
Tier 1 Capital (to average assets) ratio	8.29	8.53
Minimum amount of Tier 1 Capital for adequacy purposes	$ 245,242	$ 226,624
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	4.00	4.00
Parent Company [Member] \| Conservation Buffer [Member]
Total Capital
Minimum amount of capital for adequacy purposes	$ 502,614	$ 425,673
Minimum amount of capital for adequacy purposes, ratio	10.50	10.50
Tier I Capital (to risk-weighted assets)
Minimum amount of Tier 1 Capital for adequacy purposes	$ 406,878	$ 344,592
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	8.50	8.50
Common equity tier I
Minimum amount of common equity tier I for adequacy purposes	$ 335,076	$ 283,782
Minimum amount of common equity tier I for adequacy purposes, ratio	7.00%	7.00%
Tier I Leverage Capital (to average assets)
Minimum amount of Tier 1 Capital for adequacy purposes	$ 245,242	$ 226,624
Minimum amount of Tier 1 Capital for adequacy purposes, ratio	4.00	4.00

Minimum amount of common equity tier I for adequacy purposes, ratio.

No definition available.

Name:	pgc_TierOneRiskBasedCommonEquityRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	pgc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Minimum common equity tier I required to be well-capitalized, ratio.

+ References

No definition available.

+ Details

Name:	pgc_TierOneRiskBasedCommonEquityRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	pgc_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of total capital as defined by regulatory framework.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount of minimum total risk-based capital required for capital adequacy as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

+ Details

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

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1B
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958570-112826

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 505
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=117337116&loc=SL5958568-112826

+ Details

Name:	us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum total risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

Ratio of minimum total risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of total risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Common Equity Tier 1 risk-based capital as defined by regulatory framework.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Ratio of Common Equity Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_CommonEquityTierOneCapitalRatio
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum Common Equity Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework.

+ References

+ Details

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

- Definition

Amount of minimum Common Equity Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

Amount of Tier 1 leverage capital as defined by regulatory framework.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount of minimum Tier 1 leverage capital required for capital adequacy as defined by regulatory framework.

+ References

+ Details

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

- Definition

Ratio of minimum Tier 1 leverage capital to average assets required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum Tier 1 leverage capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

Ratio of minimum Tier 1 leverage capital to average assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of Tier 1 capital to average assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneLeverageCapitalToAverageAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of Tier 1 risk-based capital as defined by regulatory framework.

+ References

+ Details

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

- References

No definition available.

+ Details

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

- Definition

Amount of minimum Tier 1 risk-based capital required for capital adequacy as defined by regulatory framework.

+ References

+ Details

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

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets required for capital adequacy as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of minimum Tier 1 risk-based capital categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

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

- Definition

Ratio of minimum Tier 1 risk-based capital to risk-weighted assets categorized as well capitalized as defined by regulatory framework for prompt corrective action.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Definition

Ratio of Tier 1 risk-based capital to risk-weighted assets as defined by regulatory framework.

+ References

+ Details

Name:	us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:pureItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_SubsidiariesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RiskWeightedAssetsCalculationMethodologyAxis=pgc_ConservationBufferMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=srt_ParentCompanyMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: