Regulatory Matters - Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations (Details)	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)
PEOPLES
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital	$ 766,692,000	$ 604,566,000
Common equity tier one capital ratio	0.1156	0.1192
Common equity tier one capital required for capital adequacy	$ 298,393,000	$ 228,206,000
Common equity tier 1 risk based capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Common equity tier one capital required to be well-capitalized	$ 431,011,000	$ 329,631,000
Common equity tier 1 risk based capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier one risk based capital	$ 820,496,000	$ 618,354,000
Tier one risk based capital to risk weighted assets	0.1237	0.1219
Tier one risk based capital required for capital adequacy	$ 397,857,000	$ 304,274,000
Tier one risk based capital required for capital adequacy to risk weighted assets	0.0600	0.0600
Tier one risk based capital required to be well capitalized	$ 530,476,000	$ 405,699,000
Tier one risk based capital required to be well capitalized to risk weighted assets	0.0800	0.0800
Capital	$ 873,226,000	$ 662,421,000
Capital to risk ratio	0.1317	0.1306
Capital required for capital adequacy	$ 530,476,000	$ 405,699,000
Capital required for capital adequacy to risk ratio	0.0800	0.0800
Capital required to be well capitalized	$ 663,095,000	$ 507,124,000
Capital required to be well capitalized to risk ratio	0.1000	0.1000
Tier one leverage capital	$ 820,496,000	$ 618,354,000
Tier one leverage capital to ratio	0.0948	0.0892
Tier one leverage capital required for capital adequacy	$ 346,112,000	$ 277,302,000
Tier one leverage capital required for capital adequacy to average assets ratio	0.0400	0.0400
Tier one leverage capital required to be well capitalized	$ 432,640,000	$ 346,628,000
Tier one leverage capital required to be well capitalized to average assets ratio	0.0500	0.0500
Regulatory capital conservation buffer	$ 342,750,000	$ 256,722,000
Regulatory capital conservation buffer ratio	0.0517	0.0506
Risk weighted assets	6,630,945,000	5,071,240,000
PEOPLES BANK
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Common equity tier one capital	$ 783,790,000	$ 593,609,000
Common equity tier one capital ratio	0.1185	0.1172
Common equity tier one capital required for capital adequacy	$ 297,638,000	$ 227,843,000
Common equity tier 1 risk based capital required for capital adequacy to risk weighted assets	4.50%	4.50%
Common equity tier one capital required to be well-capitalized	$ 429,921,000	$ 329,107,000
Common equity tier 1 risk based capital required to be well capitalized to risk weighted assets	6.50%	6.50%
Tier one risk based capital	$ 783,790,000	$ 593,609,000
Tier one risk based capital to risk weighted assets	0.1185	0.1172
Tier one risk based capital required for capital adequacy	$ 396,850,000	$ 303,791,000
Tier one risk based capital required for capital adequacy to risk weighted assets	0.0600	0.0600
Tier one risk based capital required to be well capitalized	$ 529,134,000	$ 405,055,000
Tier one risk based capital required to be well capitalized to risk weighted assets	0.0800	0.0800
Capital	$ 836,520,000	$ 637,676,000
Capital to risk ratio	0.1265	0.1259
Capital required for capital adequacy	$ 529,134,000	$ 405,055,000
Capital required for capital adequacy to risk ratio	0.0800	0.0800
Capital required to be well capitalized	$ 661,417,000	$ 506,318,000
Capital required to be well capitalized to risk ratio	0.1000	0.1000
Tier one leverage capital	$ 783,790,000	$ 593,609,000
Tier one leverage capital to ratio	0.0912	0.0858
Tier one leverage capital required for capital adequacy	$ 343,613,000	$ 276,712,000
Tier one leverage capital required for capital adequacy to average assets ratio	0.0400	0.0400
Tier one leverage capital required to be well capitalized	$ 429,517,000	$ 345,890,000
Tier one leverage capital required to be well capitalized to average assets ratio	0.0500	0.0500
Regulatory capital conservation buffer	$ 307,386,000	$ 232,621,000
Regulatory capital conservation buffer ratio	0.0465	0.0459
Risk weighted assets	6,614,172,000	5,063,183,000
Minimum | PEOPLES
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Regulatory capital conservation buffer	165,774,000	126,781,000
Regulatory capital conservation buffer ratio	0.0250	0.0250
Minimum | PEOPLES BANK
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Regulatory capital conservation buffer	165,354,000	126,580,000
Regulatory capital conservation buffer ratio	$ 0.0250	$ 0.0250