Allowance for Loan Losses and Credit Quality of Loans, Past Due Loans (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Aging [Abstract]
Minimum number of days past due for nonaccrual loan status	90 days
Total past due accruing	$ 36,466	$ 38,067
Nonaccrual	24,669	25,487
Current	6,902,138	6,824,155
Recorded total loans	6,963,273	6,887,709
31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	26,618	26,641
61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	7,461	6,341
Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	2,387	5,085
Commercial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Recorded total loans	3,325,064	3,222,310
Consumer Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Recorded total loans	2,234,130	2,284,563
Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Recorded total loans	1,404,079	1,380,836
Originated Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	34,627	36,515
Nonaccrual	22,719	23,372
Current	6,601,013	6,505,231
Recorded total loans	6,658,359	6,565,118
Originated Loans [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	25,312	25,476
Originated Loans [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	6,948	5,969
Originated Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	2,367	5,070
Originated Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	8,136	3,980
Nonaccrual	11,862	12,031
Current	3,165,356	3,062,609
Recorded total loans	3,185,354	3,078,620
Originated Loans [Member] | Commercial Loans [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	6,371	3,090
Originated Loans [Member] | Commercial Loans [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,765	302
Originated Loans [Member] | Commercial Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	588
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,143	909
Nonaccrual	952	1,062
Current	867,661	846,148
Recorded total loans	869,756	848,119
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	43	909
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,100	0
Originated Loans [Member] | Commercial Loans [Member] | C&I [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	5,161	1,677
Nonaccrual	4,596	4,995
Current	1,822,746	1,734,558
Recorded total loans	1,832,503	1,741,230
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	4,791	1,089
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	370	0
Originated Loans [Member] | Commercial Loans [Member] | CRE [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	588
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,832	1,394
Nonaccrual	6,314	5,974
Current	474,949	481,903
Recorded total loans	483,095	489,271
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,537	1,092
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	295	302
Originated Loans [Member] | Commercial Loans [Member] | Business Banking [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Originated Loans [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	24,436	29,770
Nonaccrual	4,387	4,563
Current	2,177,725	2,218,606
Recorded total loans	2,206,548	2,252,939
Originated Loans [Member] | Consumer Loans [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	17,716	20,960
Originated Loans [Member] | Consumer Loans [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	4,353	5,510
Originated Loans [Member] | Consumer Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	2,367	3,300
Originated Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	14,293	18,005
Nonaccrual	1,737	1,971
Current	1,173,640	1,196,136
Recorded total loans	1,189,670	1,216,112
Originated Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	11,710	14,519
Originated Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,842	2,300
Originated Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	741	1,186
Originated Loans [Member] | Consumer Loans [Member] | Specialty Lending [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	6,813	6,814
Nonaccrual	0	0
Current	513,161	518,114
Recorded total loans	519,974	524,928
Originated Loans [Member] | Consumer Loans [Member] | Specialty Lending [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	3,452	3,479
Originated Loans [Member] | Consumer Loans [Member] | Specialty Lending [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,880	1,773
Originated Loans [Member] | Consumer Loans [Member] | Specialty Lending [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,481	1,562
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	3,330	4,951
Nonaccrual	2,650	2,592
Current	490,924	504,356
Recorded total loans	496,904	511,899
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	2,554	2,962
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	631	1,437
Originated Loans [Member] | Consumer Loans [Member] | Direct [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	145	552
Originated Loans [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	2,055	2,765
Nonaccrual	6,470	6,778
Current	1,257,932	1,224,016
Recorded total loans	1,266,457	1,233,559
Originated Loans [Member] | Residential Real Estate [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,225	1,426
Originated Loans [Member] | Residential Real Estate [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	830	157
Originated Loans [Member] | Residential Real Estate [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	1,182
Acquired Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,839	1,552
Nonaccrual	1,950	2,115
Current	301,125	318,924
Recorded total loans	304,914	322,591
Acquired Loans [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,306	1,165
Acquired Loans [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	513	372
Acquired Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	20	15
Acquired Loans [Member] | Commercial Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	444	754
Nonaccrual	504	390
Current	138,762	142,546
Recorded total loans	139,710	143,690
Acquired Loans [Member] | Commercial Loans [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	441	466
Acquired Loans [Member] | Commercial Loans [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	3	288
Acquired Loans [Member] | Commercial Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | C&I [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Nonaccrual	38	0
Current	33,001	26,124
Recorded total loans	33,039	26,124
Acquired Loans [Member] | Commercial Loans [Member] | C&I [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | C&I [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | C&I [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | CRE [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Nonaccrual	0	0
Current	76,362	84,492
Recorded total loans	76,362	84,492
Acquired Loans [Member] | Commercial Loans [Member] | CRE [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | CRE [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | CRE [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Commercial Loans [Member] | Business Banking [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	444	754
Nonaccrual	466	390
Current	29,399	31,930
Recorded total loans	30,309	33,074
Acquired Loans [Member] | Commercial Loans [Member] | Business Banking [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	441	466
Acquired Loans [Member] | Commercial Loans [Member] | Business Banking [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	3	288
Acquired Loans [Member] | Commercial Loans [Member] | Business Banking [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	0	0
Acquired Loans [Member] | Consumer Loans [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	259	210
Nonaccrual	96	227
Current	27,227	31,187
Recorded total loans	27,582	31,624
Acquired Loans [Member] | Consumer Loans [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	217	153
Acquired Loans [Member] | Consumer Loans [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	22	42
Acquired Loans [Member] | Consumer Loans [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	20	15
Acquired Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing		2
Nonaccrual		0
Current		30
Recorded total loans		32
Acquired Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing		1
Acquired Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing		1
Acquired Loans [Member] | Consumer Loans [Member] | Dealer Finance [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing		0
Acquired Loans [Member] | Consumer Loans [Member] | Direct [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	259	208
Nonaccrual	96	227
Current	27,227	31,157
Recorded total loans	27,582	31,592
Acquired Loans [Member] | Consumer Loans [Member] | Direct [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	217	152
Acquired Loans [Member] | Consumer Loans [Member] | Direct [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	22	41
Acquired Loans [Member] | Consumer Loans [Member] | Direct [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	20	15
Acquired Loans [Member] | Residential Real Estate [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	1,136	588
Nonaccrual	1,350	1,498
Current	135,136	145,191
Recorded total loans	137,622	147,277
Acquired Loans [Member] | Residential Real Estate [Member] | 31-60 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	648	546
Acquired Loans [Member] | Residential Real Estate [Member] | 61-90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	488	42
Acquired Loans [Member] | Residential Real Estate [Member] | Greater Than 90 Days Past Due Accruing [Member]
Financing Receivable, Recorded Investment, Aging [Abstract]
Total past due accruing	$ 0	$ 0