Regulations and Supervision - Actual Capital Amounts and Ratios (Details) $ in Thousands	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Banking Regulation, Total Capital [Abstract]
Total Capital (to risk-weighted assets), Actual Amount	$ 735,187	$ 720,755
Total Capital (to risk-weighted assets), Actual Ratio	0.142	0.144
Total Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 524,345	$ 525,755
Total Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.105	0.105
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 516,519	$ 500,719
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.100	0.100
Common Equity Tier 1 Capital (To Risk-weighted Assets)
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 688,425
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.133	0.131
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 361,563	$ 350,503
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 335,737	$ 325,467
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital (To Risk-weighted Assets)
Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 688,425	$ 667,364
Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.133	0.133
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 439,041	$ 425,611
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.085	0.085
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 413,215	$ 400,575
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.080	0.080
Tier 1 Leverage Capital (To Average Assets)
Tier 1 Capital (to average assets), Actual Amount	$ 688,425	$ 667,364
Tier 1 Capital (to average assets), Actual Ratio	0.087	0.088
Tier 1 Capital (to average assets), Minimum Capital Required, Amount	$ 315,820	$ 305,083
Tier 1 Capital (to average assets), Minimum Capital Required, Ratio	0.040	0.040
Tier 1 Capital (to average assets), Required to be Well Capitalized, Amount	$ 394,775	$ 381,354
Tier 1 Capital (to average assets), Required to be Well Capitalized, Ratio	0.050	0.050
Castile
Banking Regulation, Total Capital [Abstract]
Total Capital (to risk-weighted assets), Actual Amount	$ 160,757	$ 157,514
Total Capital (to risk-weighted assets), Actual Ratio	0.122	0.126
Total Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 138,104	$ 131,034
Total Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.105	0.105
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 131,527	$ 124,795
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.100	0.100
Common Equity Tier 1 Capital (To Risk-weighted Assets)
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 149,154	$ 144,448
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.113	0.116
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 92,069	$ 87,356
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 85,493	$ 81,117
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital (To Risk-weighted Assets)
Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 149,154	$ 144,448
Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.113	0.116
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 111,798	$ 106,076
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.085	0.085
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 105,222	$ 99,836
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.080	0.080
Tier 1 Leverage Capital (To Average Assets)
Tier 1 Capital (to average assets), Actual Amount	$ 149,154	$ 144,448
Tier 1 Capital (to average assets), Actual Ratio	0.079	0.081
Tier 1 Capital (to average assets), Minimum Capital Required, Amount	$ 75,935	$ 71,605
Tier 1 Capital (to average assets), Minimum Capital Required, Ratio	0.040	0.040
Tier 1 Capital (to average assets), Required to be Well Capitalized, Amount	$ 94,918	$ 89,507
Tier 1 Capital (to average assets), Required to be Well Capitalized, Ratio	0.050	0.050
Mahopac
Banking Regulation, Total Capital [Abstract]
Total Capital (to risk-weighted assets), Actual Amount	$ 136,247	$ 133,969
Total Capital (to risk-weighted assets), Actual Ratio	0.127	0.130
Total Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 112,649	$ 108,129
Total Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.105	0.105
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 107,285	$ 102,980
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.100	0.100
Common Equity Tier 1 Capital (To Risk-weighted Assets)
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 126,718	$ 122,393
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.118	0.119
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 75,100	$ 72,086
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 69,735	$ 66,937
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital (To Risk-weighted Assets)
Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 126,718	$ 122,393
Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.118	0.119
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 91,192	$ 87,533
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.085	0.085
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 85,282	$ 82,384
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.080	0.080
Tier 1 Leverage Capital (To Average Assets)
Tier 1 Capital (to average assets), Actual Amount	$ 126,718	$ 122,393
Tier 1 Capital (to average assets), Actual Ratio	0.081	0.082
Tier 1 Capital (to average assets), Minimum Capital Required, Amount	$ 62,815	$ 59,742
Tier 1 Capital (to average assets), Minimum Capital Required, Ratio	0.040	0.040
Tier 1 Capital (to average assets), Required to be Well Capitalized, Amount	$ 78,519	$ 74,678
Tier 1 Capital (to average assets), Required to be Well Capitalized, Ratio	0.050	0.050
VIST
Banking Regulation, Total Capital [Abstract]
Total Capital (to risk-weighted assets), Actual Amount	$ 173,889	$ 175,931
Total Capital (to risk-weighted assets), Actual Ratio	0.136	0.137
Total Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 134,403	$ 134,615
Total Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.105	0.105
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 128,003	$ 128,205
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.100	0.100
Common Equity Tier 1 Capital (To Risk-weighted Assets)
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 163,145	$ 163,895
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.128	0.128
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 89,602	$ 89,743
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 83,202	$ 83,333
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital (To Risk-weighted Assets)
Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 163,145	$ 163,895
Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.128	0.128
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 108,803	$ 108,794
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.085	0.085
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 102,403	$ 102,564
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.080	0.080
Tier 1 Leverage Capital (To Average Assets)
Tier 1 Capital (to average assets), Actual Amount	$ 163,145	$ 163,895
Tier 1 Capital (to average assets), Actual Ratio	0.084	0.084
Tier 1 Capital (to average assets), Minimum Capital Required, Amount	$ 77,953	$ 77,874
Tier 1 Capital (to average assets), Minimum Capital Required, Ratio	0.040	0.040
Tier 1 Capital (to average assets), Required to be Well Capitalized, Amount	$ 97,441	$ 83,333
Tier 1 Capital (to average assets), Required to be Well Capitalized, Ratio	0.050	0.050
Subsidiaries
Banking Regulation, Total Capital [Abstract]
Total Capital (to risk-weighted assets), Actual Amount	$ 219,976	$ 210,756
Total Capital (to risk-weighted assets), Actual Ratio	0.148	0.147
Total Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 156,631	$ 150,482
Total Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.105	0.105
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 149,172	$ 143,316
Total Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.100	0.100
Common Equity Tier 1 Capital (To Risk-weighted Assets)
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 207,632	$ 196,522
Common Equity Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.139	0.137
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 104,421	$ 100,321
Common Equity Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	7.00%	7.00%
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 96,962	$ 93,156
Common Equity Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	6.50%	6.50%
Tier 1 Capital (To Risk-weighted Assets)
Tier 1 Capital (to risk-weighted assets), Actual Amount	$ 207,632	$ 196,522
Tier 1 Capital (to risk-weighted assets), Actual Ratio	0.139	0.137
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Amount	$ 126,797	$ 121,819
Tier 1 Capital (to risk-weighted assets), Minimum Capital Required, Ratio	0.085	0.085
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Amount	$ 119,338	$ 114,653
Tier 1 Capital (to risk-weighted assets), Required to be Well Capitalized, Ratio	0.080	0.080
Tier 1 Leverage Capital (To Average Assets)
Tier 1 Capital (to average assets), Actual Amount	$ 207,632	$ 196,522
Tier 1 Capital (to average assets), Actual Ratio	0.084	0.082
Tier 1 Capital (to average assets), Minimum Capital Required, Amount	$ 99,000	$ 95,691
Tier 1 Capital (to average assets), Minimum Capital Required, Ratio	0.040	0.040
Tier 1 Capital (to average assets), Required to be Well Capitalized, Amount	$ 123,751	$ 119,614
Tier 1 Capital (to average assets), Required to be Well Capitalized, Ratio	0.050	0.050