Allowance for Credit Losses - Amortized Cost Basis by Year of Origination and Credit Quality Indicator (Details) - USD ($)	Jun. 30, 2022	Dec. 31, 2021
Credit quality
Total loans and leases	$ 13,262,781,000	$ 12,961,999,000
Loss
Credit quality
Total loans and leases	0	0
Residential mortgage
Credit quality
2021/2022	437,142,000	1,304,978,000
2020/2021	1,250,161,000	753,668,000
2019/2020	704,669,000	363,415,000
2018/2019	326,199,000	266,368,000
2017/2018	233,184,000	332,041,000
Prior	1,255,103,000	1,062,135,000
Revolving Loans Amortized Cost Basis	4,999,000	44,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,311,000	718,000
Total loans and leases	4,212,768,000	4,083,367,000
Residential mortgage | 740 and greater
Credit quality
2021/2022	352,342,000	1,101,958,000
2020/2021	1,069,214,000	635,061,000
2019/2020	587,478,000	286,993,000
2018/2019	252,428,000	198,622,000
2017/2018	178,752,000	251,906,000
Prior	974,057,000	829,175,000
Total loans and leases	3,414,271,000	3,303,715,000
Residential mortgage | 680 - 739
Credit quality
2021/2022	46,224,000	140,997,000
2020/2021	124,306,000	81,590,000
2019/2020	79,422,000	45,163,000
2018/2019	45,117,000	27,315,000
2017/2018	21,882,000	32,855,000
Prior	144,226,000	125,906,000
Total loans and leases	461,177,000	453,826,000
Residential mortgage | 620 - 679
Credit quality
2021/2022	5,305,000	15,781,000
2020/2021	19,143,000	11,943,000
2019/2020	14,291,000	5,268,000
2018/2019	5,405,000	10,149,000
2017/2018	3,892,000	9,069,000
Prior	38,470,000	37,404,000
Total loans and leases	86,506,000	89,614,000
Residential mortgage | 550 - 619
Credit quality
2021/2022	169,000	1,735,000
2020/2021	1,943,000	873,000
2019/2020	294,000	698,000
2018/2019	226,000	533,000
2017/2018	2,073,000	2,033,000
Prior	8,017,000	7,475,000
Total loans and leases	12,722,000	13,347,000
Residential mortgage | Less than 550
Credit quality
2021/2022	2,085,000
2020/2021	1,242,000
2019/2020	60,000
2018/2019		345,000
2017/2018	340,000	2,603,000
Prior	4,656,000	2,838,000
Total loans and leases	8,383,000	5,786,000
Residential mortgage | No Score
Credit quality
2021/2022	10,652,000	18,882,000
2020/2021	14,868,000	7,938,000
2019/2020	7,544,000	15,051,000
2018/2019	13,471,000	18,107,000
2017/2018	16,488,000	17,333,000
Prior	54,373,000	42,185,000
Total loans and leases	117,396,000	119,496,000
Residential mortgage | Fico Other
Credit quality
2021/2022	20,365,000	25,625,000
2020/2021	19,445,000	16,263,000
2019/2020	15,580,000	10,242,000
2018/2019	9,552,000	11,297,000
2017/2018	9,757,000	16,242,000
Prior	31,304,000	17,152,000
Revolving Loans Amortized Cost Basis	4,999,000	44,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,311,000	718,000
Total loans and leases	112,313,000	97,583,000
Home equity line
Credit quality
Revolving Loans Amortized Cost Basis	961,690,000	867,251,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	9,879,000	9,357,000
Total loans and leases	971,569,000	876,608,000
Home equity line | 740 and greater
Credit quality
Revolving Loans Amortized Cost Basis	748,148,000	671,566,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	2,227,000	1,873,000
Total loans and leases	750,375,000	673,439,000
Home equity line | 680 - 739
Credit quality
Revolving Loans Amortized Cost Basis	157,042,000	141,889,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	3,106,000	3,968,000
Total loans and leases	160,148,000	145,857,000
Home equity line | 620 - 679
Credit quality
Revolving Loans Amortized Cost Basis	40,070,000	37,815,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	2,454,000	2,500,000
Total loans and leases	42,524,000	40,315,000
Home equity line | 550 - 619
Credit quality
Revolving Loans Amortized Cost Basis	9,202,000	9,090,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,601,000	948,000
Total loans and leases	10,803,000	10,038,000
Home equity line | Less than 550
Credit quality
Revolving Loans Amortized Cost Basis	1,159,000	2,574,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	491,000	68,000
Total loans and leases	1,650,000	2,642,000
Home equity line | No Score
Credit quality
Revolving Loans Amortized Cost Basis	6,069,000	4,317,000
Total loans and leases	6,069,000	4,317,000
Total loans
Credit quality
2021/2022	1,464,991,000	3,157,488,000
2020/2021	2,889,385,000	1,588,735,000
2019/2020	1,451,390,000	1,632,764,000
2018/2019	1,355,953,000	1,164,714,000
2017/2018	973,418,000	954,259,000
Prior	2,933,309,000	2,359,432,000
Revolving Loans Amortized Cost Basis	2,159,463,000	2,033,383,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	34,872,000	71,224,000
Total loans and leases	13,262,781,000	12,961,999,000
Residential. Mortgage
Credit quality
Total loans and leases	4,212,768,000	4,083,367,000
Home equity Line
Credit quality
Total loans and leases	971,569,000	876,608,000
Consumer
Credit quality
2021/2022	185,402,000	306,140,000
2020/2021	261,161,000	174,166,000
2019/2020	140,273,000	184,913,000
2018/2019	139,876,000	124,197,000
2017/2018	85,721,000	67,459,000
Prior	54,270,000	24,158,000
Revolving Loans Amortized Cost Basis	336,749,000	344,870,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	3,599,000	4,036,000
Total loans and leases	1,207,051,000	1,229,939,000
Consumer | 740 and greater
Credit quality
2021/2022	115,911,000	155,929,000
2020/2021	132,565,000	83,337,000
2019/2020	66,828,000	79,617,000
2018/2019	59,155,000	56,707,000
2017/2018	38,001,000	24,525,000
Prior	17,426,000	8,067,000
Revolving Loans Amortized Cost Basis	117,266,000	117,843,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	203,000	209,000
Total loans and leases	547,355,000	526,234,000
Consumer | 680 - 739
Credit quality
2021/2022	53,590,000	93,214,000
2020/2021	80,240,000	56,327,000
2019/2020	45,783,000	55,126,000
2018/2019	41,393,000	34,049,000
2017/2018	23,562,000	17,527,000
Prior	13,947,000	6,315,000
Revolving Loans Amortized Cost Basis	67,636,000	69,366,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	566,000	707,000
Total loans and leases	326,717,000	332,631,000
Consumer | 620 - 679
Credit quality
2021/2022	11,760,000	41,671,000
2020/2021	35,430,000	21,986,000
2019/2020	17,746,000	28,491,000
2018/2019	22,180,000	19,403,000
2017/2018	13,928,000	12,952,000
Prior	11,374,000	5,324,000
Revolving Loans Amortized Cost Basis	30,079,000	31,165,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,018,000	1,175,000
Total loans and leases	143,515,000	162,167,000
Consumer | 550 - 619
Credit quality
2021/2022	1,000,000	7,836,000
2020/2021	6,548,000	8,265,000
2019/2020	6,576,000	13,265,000
2018/2019	10,400,000	10,497,000
2017/2018	7,652,000	7,469,000
Prior	6,801,000	3,244,000
Revolving Loans Amortized Cost Basis	10,044,000	10,359,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	1,026,000	1,089,000
Total loans and leases	50,047,000	62,024,000
Consumer | Less than 550
Credit quality
2021/2022	379,000	2,272,000
2020/2021	1,758,000	3,867,000
2019/2020	2,973,000	6,646,000
2018/2019	5,022,000	3,484,000
2017/2018	2,547,000	2,739,000
Prior	2,525,000	1,175,000
Revolving Loans Amortized Cost Basis	3,047,000	3,195,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	483,000	536,000
Total loans and leases	18,734,000	23,914,000
Consumer | No Score
Credit quality
2021/2022	1,087,000	481,000
2020/2021	402,000	19,000
2019/2020	9,000	56,000
2018/2019	52,000	40,000
2017/2018	31,000	65,000
Prior	45,000	2,000
Revolving Loans Amortized Cost Basis	37,536,000	35,414,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	303,000	320,000
Total loans and leases	39,465,000	36,397,000
Consumer | Fico Other
Credit quality
2021/2022	1,675,000	4,737,000
2020/2021	4,218,000	365,000
2019/2020	358,000	1,712,000
2018/2019	1,674,000	17,000
2017/2018		2,182,000
Prior	2,152,000	31,000
Revolving Loans Amortized Cost Basis	71,141,000	77,528,000
Total loans and leases	81,218,000	86,572,000
Residential Mortgage.
Credit quality
2021/2022	437,142,000	1,304,978,000
2020/2021	1,250,161,000	753,668,000
2019/2020	704,669,000	363,415,000
2018/2019	326,199,000	266,368,000
2017/2018	233,184,000	332,041,000
Prior	1,255,103,000	1,062,135,000
Revolving Loans Amortized Cost Basis	966,689,000	867,295,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	11,190,000	10,075,000
Total loans and leases	5,184,337,000	4,959,975,000
Commercial and Industrial
Credit quality
2021/2022	231,926,000	637,126,000
2020/2021	432,230,000	142,497,000
2019/2020	80,863,000	237,293,000
2018/2019	191,968,000	106,699,000
2017/2018	65,428,000	32,409,000
Prior	164,397,000	177,825,000
Revolving Loans Amortized Cost Basis	755,237,000	711,028,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	20,083,000	42,222,000
Total loans and leases	1,942,132,000	2,087,099,000
Commercial and Industrial | Pass
Credit quality
2021/2022	216,303,000	623,098,000
2020/2021	421,981,000	129,665,000
2019/2020	66,601,000	223,388,000
2018/2019	182,175,000	88,409,000
2017/2018	60,586,000	29,380,000
Prior	156,647,000	168,591,000
Revolving Loans Amortized Cost Basis	697,256,000	644,947,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	19,128,000	40,193,000
Total loans and leases	1,820,677,000	1,947,671,000
Commercial and Industrial | Special mention
Credit quality
2021/2022	2,816,000	397,000
2020/2021	316,000	4,382,000
2019/2020	1,628,000	4,213,000
2018/2019	2,822,000	12,552,000
2017/2018	748,000	974,000
Prior	5,295,000	5,313,000
Revolving Loans Amortized Cost Basis	1,073,000	4,804,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	841,000	986,000
Total loans and leases	15,539,000	33,621,000
Commercial and Industrial | Substandard
Credit quality
2021/2022		354,000
2020/2021	320,000	1,380,000
2019/2020	1,103,000	1,951,000
2018/2019	1,605,000	1,285,000
2017/2018	1,019,000	60,000
Prior	879,000	3,551,000
Revolving Loans Amortized Cost Basis	16,214,000	17,893,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	114,000	1,043,000
Total loans and leases	21,254,000	27,517,000
Commercial and Industrial | Other Indicator
Credit quality
2021/2022	12,807,000	13,277,000
2020/2021	9,613,000	7,070,000
2019/2020	11,531,000	7,741,000
2018/2019	5,366,000	4,453,000
2017/2018	3,075,000	1,995,000
Prior	1,576,000	370,000
Revolving Loans Amortized Cost Basis	40,694,000	43,384,000
Total loans and leases	84,662,000	78,290,000
Commercial real estate
Credit quality
2021/2022	516,062,000	693,370,000
2020/2021	695,446,000	338,140,000
2019/2020	339,133,000	582,386,000
2018/2019	563,991,000	496,985,000
2017/2018	461,114,000	440,863,000
Prior	1,296,210,000	986,450,000
Revolving Loans Amortized Cost Basis	84,872,000	86,538,000
Revolving Loans Converted to Term Loans Amortized Cost Basis		14,891,000
Total loans and leases	3,956,828,000	3,639,623,000
Commercial real estate | Pass
Credit quality
2021/2022	516,062,000	693,370,000
2020/2021	695,446,000	338,140,000
2019/2020	338,391,000	533,887,000
2018/2019	516,210,000	487,739,000
2017/2018	459,372,000	415,186,000
Prior	1,270,438,000	940,732,000
Revolving Loans Amortized Cost Basis	84,174,000	78,479,000
Revolving Loans Converted to Term Loans Amortized Cost Basis		14,891,000
Total loans and leases	3,880,093,000	3,502,424,000
Commercial real estate | Special mention
Credit quality
2019/2020	562,000	48,499,000
2018/2019	47,781,000	7,470,000
2017/2018		25,513,000
Prior	11,140,000	30,255,000
Revolving Loans Amortized Cost Basis	695,000	7,600,000
Total loans and leases	60,178,000	119,337,000
Commercial real estate | Substandard
Credit quality
2019/2020	180,000
2018/2019		1,776,000
2017/2018	1,742,000	164,000
Prior	14,476,000	15,303,000
Revolving Loans Amortized Cost Basis	3,000	459,000
Total loans and leases	16,401,000	17,702,000
Commercial real estate | Other Indicator
Credit quality
Prior	156,000	160,000
Total loans and leases	156,000	160,000
Construction
Credit quality
2021/2022	52,803,000	181,393,000
2020/2021	223,117,000	116,642,000
2019/2020	133,726,000	214,875,000
2018/2019	88,556,000	160,689,000
2017/2018	120,145,000	65,454,000
Prior	93,508,000	51,264,000
Revolving Loans Amortized Cost Basis	15,916,000	23,652,000
Total loans and leases	727,771,000	813,969,000
Construction | Pass
Credit quality
2021/2022	39,575,000	154,558,000
2020/2021	193,588,000	107,767,000
2019/2020	127,677,000	210,314,000
2018/2019	85,471,000	155,311,000
2017/2018	115,881,000	62,770,000
Prior	88,509,000	48,021,000
Revolving Loans Amortized Cost Basis	14,965,000	22,859,000
Total loans and leases	665,666,000	761,600,000
Construction | Special mention
Credit quality
2019/2020		244,000
2018/2019	236,000	707,000
Prior	350,000	356,000
Total loans and leases	586,000	1,307,000
Construction | Substandard
Credit quality
2018/2019		363,000
2017/2018	351,000
Prior	498,000	839,000
Total loans and leases	849,000	1,202,000
Construction | Other Indicator
Credit quality
2021/2022	13,228,000	26,835,000
2020/2021	29,529,000	8,875,000
2019/2020	6,049,000	4,317,000
2018/2019	2,849,000	4,308,000
2017/2018	3,913,000	2,684,000
Prior	4,151,000	2,048,000
Revolving Loans Amortized Cost Basis	951,000	793,000
Total loans and leases	60,670,000	49,860,000
Lease financing
Credit quality
2021/2022	41,656,000	34,481,000
2020/2021	27,270,000	63,622,000
2019/2020	52,726,000	49,882,000
2018/2019	45,363,000	9,776,000
2017/2018	7,826,000	16,033,000
Prior	69,821,000	57,600,000
Total loans and leases	244,662,000	231,394,000
Lease financing | Pass
Credit quality
2021/2022	41,656,000	33,980,000
2020/2021	26,813,000	60,650,000
2019/2020	49,889,000	48,236,000
2018/2019	43,989,000	9,449,000
2017/2018	7,801,000	15,009,000
Prior	68,457,000	57,130,000
Total loans and leases	238,605,000	224,454,000
Lease financing | Special mention
Credit quality
2021/2022		501,000
2020/2021	457,000	2,702,000
2019/2020	2,642,000	1,506,000
2018/2019	1,358,000	311,000
2017/2018	11,000	153,000
Prior	17,000
Total loans and leases	4,485,000	5,173,000
Lease financing | Substandard
Credit quality
2020/2021		270,000
2019/2020	195,000	140,000
2018/2019	16,000	16,000
2017/2018	14,000	871,000
Prior	1,347,000	470,000
Total loans and leases	1,572,000	1,767,000
Commercial Lending
Credit quality
2021/2022	842,447,000	1,546,370,000
2020/2021	1,378,063,000	660,901,000
2019/2020	606,448,000	1,084,436,000
2018/2019	889,878,000	774,149,000
2017/2018	654,513,000	554,759,000
Prior	1,623,936,000	1,273,139,000
Revolving Loans Amortized Cost Basis	856,025,000	821,218,000
Revolving Loans Converted to Term Loans Amortized Cost Basis	20,083,000	57,113,000
Total loans and leases	$ 6,871,393,000	$ 6,772,085,000