Allowance for Credit Losses - Amortized Cost Basis by Year of Origination and Credit Quality Indicator (Details) - USD ($)	Sep. 30, 2022	Dec. 31, 2021
Credit quality
Financing Receivable, before Allowance for Credit Loss, Total	$ 13,700,374,000	$ 12,961,999,000
Loss
Credit quality
Financing Receivable, before Allowance for Credit Loss, Total	0	0
Residential Lending: Residential Mortgage
Credit quality
2021/2022	573,425,000	1,304,978,000
2020/2021	1,235,019,000	753,668,000
2019/2020	691,475,000	363,415,000
2018/2019	316,116,000	266,368,000
2017/2018	222,200,000	332,041,000
Prior	1,207,389,000	1,062,135,000
Revolving Loans Amortized Cost Basis	5,861,000	44,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	556,000	718,000
Financing Receivable, before Allowance for Credit Loss, Total	4,252,041,000	4,083,367,000
Residential Lending: Residential Mortgage | 740 and greater
Credit quality
2021/2022	474,234,000	1,101,958,000
2020/2021	1,056,814,000	635,061,000
2019/2020	577,378,000	286,993,000
2018/2019	244,169,000	198,622,000
2017/2018	169,100,000	251,906,000
Prior	941,705,000	829,175,000
Financing Receivable, before Allowance for Credit Loss, Total	3,463,400,000	3,303,715,000
Residential Lending: Residential Mortgage | 680 - 739
Credit quality
2021/2022	54,037,000	140,997,000
2020/2021	122,420,000	81,590,000
2019/2020	77,660,000	45,163,000
2018/2019	44,519,000	27,315,000
2017/2018	21,581,000	32,855,000
Prior	137,573,000	125,906,000
Financing Receivable, before Allowance for Credit Loss, Total	457,790,000	453,826,000
Residential Lending: Residential Mortgage | 620 - 679
Credit quality
2021/2022	7,749,000	15,781,000
2020/2021	19,021,000	11,943,000
2019/2020	13,776,000	5,268,000
2018/2019	4,801,000	10,149,000
2017/2018	3,868,000	9,069,000
Prior	35,926,000	37,404,000
Financing Receivable, before Allowance for Credit Loss, Total	85,141,000	89,614,000
Residential Lending: Residential Mortgage | 550 - 619
Credit quality
2021/2022	168,000	1,735,000
2020/2021	1,930,000	873,000
2019/2020	292,000	698,000
2018/2019	225,000	533,000
2017/2018	2,060,000	2,033,000
Prior	7,225,000	7,475,000
Financing Receivable, before Allowance for Credit Loss, Total	11,900,000	13,347,000
Residential Lending: Residential Mortgage | Less than 550
Credit quality
2021/2022	2,053,000
2020/2021	1,236,000
2019/2020	59,000
2018/2019		345,000
2017/2018	339,000	2,603,000
Prior	4,621,000	2,838,000
Financing Receivable, before Allowance for Credit Loss, Total	8,308,000	5,786,000
Residential Lending: Residential Mortgage | No Score
Credit quality
2021/2022	16,029,000	18,882,000
2020/2021	14,771,000	7,938,000
2019/2020	6,874,000	15,051,000
2018/2019	13,004,000	18,107,000
2017/2018	16,023,000	17,333,000
Prior	50,871,000	42,185,000
Financing Receivable, before Allowance for Credit Loss, Total	117,572,000	119,496,000
Residential Lending: Residential Mortgage | Fico Other
Credit quality
2021/2022	19,155,000	25,625,000
2020/2021	18,827,000	16,263,000
2019/2020	15,436,000	10,242,000
2018/2019	9,398,000	11,297,000
2017/2018	9,229,000	16,242,000
Prior	29,468,000	17,152,000
Revolving Loans Amortized Cost Basis	5,861,000	44,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	556,000	718,000
Financing Receivable, before Allowance for Credit Loss, Total	107,930,000	97,583,000
Residential Lending: Home Equity Line
Credit quality
Revolving Loans Amortized Cost Basis	1,002,034,000	867,251,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	8,597,000	9,357,000
Financing Receivable, before Allowance for Credit Loss, Total	1,010,631,000	876,608,000
Residential Lending: Home Equity Line | 740 and greater
Credit quality
Revolving Loans Amortized Cost Basis	781,307,000	671,566,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,961,000	1,873,000
Financing Receivable, before Allowance for Credit Loss, Total	783,268,000	673,439,000
Residential Lending: Home Equity Line | 680 - 739
Credit quality
Revolving Loans Amortized Cost Basis	164,166,000	141,889,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	2,650,000	3,968,000
Financing Receivable, before Allowance for Credit Loss, Total	166,816,000	145,857,000
Residential Lending: Home Equity Line | 620 - 679
Credit quality
Revolving Loans Amortized Cost Basis	42,043,000	37,815,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	2,124,000	2,500,000
Financing Receivable, before Allowance for Credit Loss, Total	44,167,000	40,315,000
Residential Lending: Home Equity Line | 550 - 619
Credit quality
Revolving Loans Amortized Cost Basis	8,719,000	9,090,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,375,000	948,000
Financing Receivable, before Allowance for Credit Loss, Total	10,094,000	10,038,000
Residential Lending: Home Equity Line | Less than 550
Credit quality
Revolving Loans Amortized Cost Basis	1,157,000	2,574,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	487,000	68,000
Financing Receivable, before Allowance for Credit Loss, Total	1,644,000	2,642,000
Residential Lending: Home Equity Line | No Score
Credit quality
Revolving Loans Amortized Cost Basis	4,642,000	4,317,000
Financing Receivable, before Allowance for Credit Loss, Total	4,642,000	4,317,000
Total loans
Credit quality
2021/2022	2,091,269,000	3,157,488,000
2020/2021	2,881,813,000	1,588,735,000
2019/2020	1,379,350,000	1,632,764,000
2018/2019	1,326,261,000	1,164,714,000
2017/2018	931,384,000	954,259,000
Prior	2,829,980,000	2,359,432,000
Revolving Loans Amortized Cost Basis	2,231,215,000	2,033,383,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	29,102,000	71,224,000
Financing Receivable, before Allowance for Credit Loss, Total	13,700,374,000	12,961,999,000
Residential Mortgage
Credit quality
Financing Receivable, before Allowance for Credit Loss, Total	4,252,041,000	4,083,367,000
Home equity Line
Credit quality
Financing Receivable, before Allowance for Credit Loss, Total	1,010,631,000	876,608,000
Consumer
Credit quality
2021/2022	274,605,000	306,140,000
2020/2021	237,868,000	174,166,000
2019/2020	125,425,000	184,913,000
2018/2019	121,542,000	124,197,000
2017/2018	70,224,000	67,459,000
Prior	40,376,000	24,158,000
Revolving Loans Amortized Cost Basis	345,449,000	344,870,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	3,396,000	4,036,000
Financing Receivable, before Allowance for Credit Loss, Total	1,218,885,000	1,229,939,000
Consumer | 740 and greater
Credit quality
2021/2022	167,566,000	155,929,000
2020/2021	120,725,000	83,337,000
2019/2020	59,620,000	79,617,000
2018/2019	50,907,000	56,707,000
2017/2018	30,750,000	24,525,000
Prior	12,114,000	8,067,000
Revolving Loans Amortized Cost Basis	116,628,000	117,843,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	195,000	209,000
Financing Receivable, before Allowance for Credit Loss, Total	558,505,000	526,234,000
Consumer | 680 - 739
Credit quality
2021/2022	80,920,000	93,214,000
2020/2021	72,861,000	56,327,000
2019/2020	41,177,000	55,126,000
2018/2019	36,236,000	34,049,000
2017/2018	19,242,000	17,527,000
Prior	10,311,000	6,315,000
Revolving Loans Amortized Cost Basis	68,968,000	69,366,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	569,000	707,000
Financing Receivable, before Allowance for Credit Loss, Total	330,284,000	332,631,000
Consumer | 620 - 679
Credit quality
2021/2022	19,673,000	41,671,000
2020/2021	32,216,000	21,986,000
2019/2020	15,779,000	28,491,000
2018/2019	19,379,000	19,403,000
2017/2018	11,622,000	12,952,000
Prior	8,584,000	5,324,000
Revolving Loans Amortized Cost Basis	30,441,000	31,165,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,033,000	1,175,000
Financing Receivable, before Allowance for Credit Loss, Total	138,727,000	162,167,000
Consumer | 550 - 619
Credit quality
2021/2022	2,159,000	7,836,000
2020/2021	5,975,000	8,265,000
2019/2020	5,859,000	13,265,000
2018/2019	9,266,000	10,497,000
2017/2018	6,476,000	7,469,000
Prior	5,188,000	3,244,000
Revolving Loans Amortized Cost Basis	9,803,000	10,359,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	983,000	1,089,000
Financing Receivable, before Allowance for Credit Loss, Total	45,709,000	62,024,000
Consumer | Less than 550
Credit quality
2021/2022	520,000	2,272,000
2020/2021	1,557,000	3,867,000
2019/2020	2,631,000	6,646,000
2018/2019	4,311,000	3,484,000
2017/2018	2,106,000	2,739,000
Prior	1,991,000	1,175,000
Revolving Loans Amortized Cost Basis	2,923,000	3,195,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	379,000	536,000
Financing Receivable, before Allowance for Credit Loss, Total	16,418,000	23,914,000
Consumer | No Score
Credit quality
2021/2022	2,122,000	481,000
2020/2021	337,000	19,000
2019/2020	1,000	56,000
2018/2019	50,000	40,000
2017/2018	28,000	65,000
Prior	35,000	2,000
Revolving Loans Amortized Cost Basis	38,831,000	35,414,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	237,000	320,000
Financing Receivable, before Allowance for Credit Loss, Total	41,641,000	36,397,000
Consumer | Fico Other
Credit quality
2021/2022	1,645,000	4,737,000
2020/2021	4,197,000	365,000
2019/2020	358,000	1,712,000
2018/2019	1,393,000	17,000
2017/2018		2,182,000
Prior	2,153,000	31,000
Revolving Loans Amortized Cost Basis	77,855,000	77,528,000
Financing Receivable, before Allowance for Credit Loss, Total	87,601,000	86,572,000
Residential Mortgage loans
Credit quality
2021/2022	573,425,000	1,304,978,000
2020/2021	1,235,019,000	753,668,000
2019/2020	691,475,000	363,415,000
2018/2019	316,116,000	266,368,000
2017/2018	222,200,000	332,041,000
Prior	1,207,389,000	1,062,135,000
Revolving Loans Amortized Cost Basis	1,007,895,000	867,295,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	9,153,000	10,075,000
Financing Receivable, before Allowance for Credit Loss, Total	5,262,672,000	4,959,975,000
Commercial and Industrial
Credit quality
2021/2022	326,051,000	637,126,000
2020/2021	435,553,000	142,497,000
2019/2020	67,731,000	237,293,000
2018/2019	186,279,000	106,699,000
2017/2018	59,443,000	32,409,000
Prior	155,486,000	177,825,000
Revolving Loans Amortized Cost Basis	796,711,000	711,028,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	16,553,000	42,222,000
Financing Receivable, before Allowance for Credit Loss, Total	2,043,807,000	2,087,099,000
Commercial and Industrial | Pass
Credit quality
2021/2022	310,400,000	623,098,000
2020/2021	425,853,000	129,665,000
2019/2020	55,272,000	223,388,000
2018/2019	177,670,000	88,409,000
2017/2018	55,923,000	29,380,000
Prior	151,156,000	168,591,000
Revolving Loans Amortized Cost Basis	709,823,000	644,947,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	15,997,000	40,193,000
Financing Receivable, before Allowance for Credit Loss, Total	1,902,094,000	1,947,671,000
Commercial and Industrial | Special mention
Credit quality
2021/2022	2,179,000	397,000
2020/2021	274,000	4,382,000
2019/2020	1,492,000	4,213,000
2018/2019	2,562,000	12,552,000
2017/2018	209,000	974,000
Prior	1,776,000	5,313,000
Revolving Loans Amortized Cost Basis	31,747,000	4,804,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	467,000	986,000
Financing Receivable, before Allowance for Credit Loss, Total	40,706,000	33,621,000
Commercial and Industrial | Substandard
Credit quality
2021/2022	655,000	354,000
2020/2021	719,000	1,380,000
2019/2020	872,000	1,951,000
2018/2019	1,383,000	1,285,000
2017/2018	956,000	60,000
Prior	1,196,000	3,551,000
Revolving Loans Amortized Cost Basis	14,728,000	17,893,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	89,000	1,043,000
Financing Receivable, before Allowance for Credit Loss, Total	20,598,000	27,517,000
Commercial and Industrial | Other Indicator
Credit quality
2021/2022	12,817,000	13,277,000
2020/2021	8,707,000	7,070,000
2019/2020	10,095,000	7,741,000
2018/2019	4,664,000	4,453,000
2017/2018	2,355,000	1,995,000
Prior	1,358,000	370,000
Revolving Loans Amortized Cost Basis	40,413,000	43,384,000
Financing Receivable, before Allowance for Credit Loss, Total	80,409,000	78,290,000
Commercial real estate
Credit quality
2021/2022	700,968,000	693,370,000
2020/2021	696,763,000	338,140,000
2019/2020	356,727,000	582,386,000
2018/2019	563,329,000	496,985,000
2017/2018	451,993,000	440,863,000
Prior	1,266,766,000	986,450,000
Revolving Loans Amortized Cost Basis	66,764,000	86,538,000
Revolving Loans Converted to Term Loans Amortized Cost Basis		14,891,000
Financing Receivable, before Allowance for Credit Loss, Total	4,103,310,000	3,639,623,000
Commercial real estate | Pass
Credit quality
2021/2022	700,785,000	693,370,000
2020/2021	696,763,000	338,140,000
2019/2020	355,992,000	533,887,000
2018/2019	548,364,000	487,739,000
2017/2018	449,754,000	415,186,000
Prior	1,242,315,000	940,732,000
Revolving Loans Amortized Cost Basis	66,075,000	78,479,000
Revolving Loans Converted to Term Loans Amortized Cost Basis		14,891,000
Financing Receivable, before Allowance for Credit Loss, Total	4,060,048,000	3,502,424,000
Commercial real estate | Special mention
Credit quality
2021/2022	183,000
2019/2020	559,000	48,499,000
2018/2019	14,965,000	7,470,000
2017/2018	515,000	25,513,000
Prior	9,549,000	30,255,000
Revolving Loans Amortized Cost Basis	687,000	7,600,000
Financing Receivable, before Allowance for Credit Loss, Total	26,458,000	119,337,000
Commercial real estate | Substandard
Credit quality
2019/2020	176,000
2018/2019		1,776,000
2017/2018	1,724,000	164,000
Prior	14,749,000	15,303,000
Revolving Loans Amortized Cost Basis	2,000	459,000
Financing Receivable, before Allowance for Credit Loss, Total	16,651,000	17,702,000
Commercial real estate | Other Indicator
Credit quality
Prior	153,000	160,000
Financing Receivable, before Allowance for Credit Loss, Total	153,000	160,000
Construction
Credit quality
2021/2022	105,657,000	181,393,000
2020/2021	250,726,000	116,642,000
2019/2020	88,570,000	214,875,000
2018/2019	95,332,000	160,689,000
2017/2018	120,598,000	65,454,000
Prior	90,583,000	51,264,000
Revolving Loans Amortized Cost Basis	14,396,000	23,652,000
Financing Receivable, before Allowance for Credit Loss, Total	765,862,000	813,969,000
Construction | Pass
Credit quality
2021/2022	83,233,000	154,558,000
2020/2021	225,116,000	107,767,000
2019/2020	84,312,000	210,314,000
2018/2019	92,856,000	155,311,000
2017/2018	116,344,000	62,770,000
Prior	86,722,000	48,021,000
Revolving Loans Amortized Cost Basis	13,443,000	22,859,000
Financing Receivable, before Allowance for Credit Loss, Total	702,026,000	761,600,000
Construction | Special mention
Credit quality
2019/2020		244,000
2018/2019	229,000	707,000
Prior		356,000
Financing Receivable, before Allowance for Credit Loss, Total	229,000	1,307,000
Construction | Substandard
Credit quality
2018/2019		363,000
2017/2018	346,000
Prior	494,000	839,000
Financing Receivable, before Allowance for Credit Loss, Total	840,000	1,202,000
Construction | Other Indicator
Credit quality
2021/2022	22,424,000	26,835,000
2020/2021	25,610,000	8,875,000
2019/2020	4,258,000	4,317,000
2018/2019	2,247,000	4,308,000
2017/2018	3,908,000	2,684,000
Prior	3,367,000	2,048,000
Revolving Loans Amortized Cost Basis	953,000	793,000
Financing Receivable, before Allowance for Credit Loss, Total	62,767,000	49,860,000
Lease financing
Credit quality
2021/2022	110,563,000	34,481,000
2020/2021	25,884,000	63,622,000
2019/2020	49,422,000	49,882,000
2018/2019	43,663,000	9,776,000
2017/2018	6,926,000	16,033,000
Prior	69,380,000	57,600,000
Financing Receivable, before Allowance for Credit Loss, Total	305,838,000	231,394,000
Lease financing | Pass
Credit quality
2021/2022	110,563,000	33,980,000
2020/2021	25,450,000	60,650,000
2019/2020	46,635,000	48,236,000
2018/2019	42,307,000	9,449,000
2017/2018	6,904,000	15,009,000
Prior	68,028,000	57,130,000
Financing Receivable, before Allowance for Credit Loss, Total	299,887,000	224,454,000
Lease financing | Special mention
Credit quality
2021/2022		501,000
2020/2021	434,000	2,702,000
2019/2020	2,591,000	1,506,000
2018/2019	1,342,000	311,000
2017/2018	9,000	153,000
Financing Receivable, before Allowance for Credit Loss, Total	4,376,000	5,173,000
Lease financing | Substandard
Credit quality
2020/2021		270,000
2019/2020	196,000	140,000
2018/2019	14,000	16,000
2017/2018	13,000	871,000
Prior	1,352,000	470,000
Financing Receivable, before Allowance for Credit Loss, Total	1,575,000	1,767,000
Commercial Lending
Credit quality
2021/2022	1,243,239,000	1,546,370,000
2020/2021	1,408,926,000	660,901,000
2019/2020	562,450,000	1,084,436,000
2018/2019	888,603,000	774,149,000
2017/2018	638,960,000	554,759,000
Prior	1,582,215,000	1,273,139,000
Revolving Loans Amortized Cost Basis	877,871,000	821,218,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	16,553,000	57,113,000
Financing Receivable, before Allowance for Credit Loss, Total	$ 7,218,817,000	$ 6,772,085,000