Loans and Leases and the Allowance for Loan and Lease Losses (Aging Analysis) (Details 4) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Dec. 31, 2019
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	$ 20,195	$ 17,380
Total Past Due and Non-Accrual	43,682	82,527
Current	11,761,688	10,908,365
Total Loans and Leases	11,805,370	10,990,892
Non-Accrual Loans and Leases that are Current	$ 11,053	11,506
Number of days non-accrual loans are not past due	30 days
30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	$ 10,533	45,964
60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	4,069	10,777
Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	8,885	8,406
Commercial
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	9,131	10,074
Total Past Due and Non-Accrual	10,123	26,626
Current	5,012,636	4,187,201
Total Loans and Leases	5,022,759	4,213,827
Non-Accrual Loans and Leases that are Current	9,045	9,665
Commercial | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	910	16,353
Commercial | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	82	199
Commercial | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Commercial | Commercial and Industrial
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	459	830
Total Past Due and Non-Accrual	834	13,512
Current	1,956,105	1,365,640
Total Loans and Leases	1,956,939	1,379,152
Non-Accrual Loans and Leases that are Current	373	421
Commercial | Commercial and Industrial | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	293	12,534
Commercial | Commercial and Industrial | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	82	148
Commercial | Commercial and Industrial | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Commercial | Commercial Mortgage
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	8,672	9,244
Total Past Due and Non-Accrual	8,672	12,242
Current	2,698,862	2,505,809
Total Loans and Leases	2,707,534	2,518,051
Non-Accrual Loans and Leases that are Current	8,672	9,244
Commercial | Commercial Mortgage | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	2,998
Commercial | Commercial Mortgage | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Commercial | Commercial Mortgage | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Commercial | Construction
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	0	0
Total Past Due and Non-Accrual	0	152
Current	245,099	194,018
Total Loans and Leases	245,099	194,170
Non-Accrual Loans and Leases that are Current	0	0
Commercial | Construction | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	101
Commercial | Construction | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	51
Commercial | Construction | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Commercial | Lease Financing
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	0	0
Total Past Due and Non-Accrual	617	720
Current	112,570	121,734
Total Loans and Leases	113,187	122,454
Non-Accrual Loans and Leases that are Current	0	0
Commercial | Lease Financing | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	617	720
Commercial | Lease Financing | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Commercial | Lease Financing | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	0	0
Consumer
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	11,064	7,306
Total Past Due and Non-Accrual	33,559	55,901
Current	6,749,052	6,721,164
Total Loans and Leases	6,782,611	6,777,065
Non-Accrual Loans and Leases that are Current	2,008	1,841
Consumer | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	9,623	29,611
Consumer | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	3,987	10,578
Consumer | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	8,885	8,406
Consumer | Residential Mortgage
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	5,888	4,125
Total Past Due and Non-Accrual	17,482	14,131
Current	3,971,911	3,876,969
Total Loans and Leases	3,989,393	3,891,100
Non-Accrual Loans and Leases that are Current	657	1,429
Consumer | Residential Mortgage | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	4,736	6,097
Consumer | Residential Mortgage | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	1,921	2,070
Consumer | Residential Mortgage | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	4,937	1,839
Consumer | Home Equity
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	5,176	3,181
Total Past Due and Non-Accrual	10,312	13,535
Current	1,630,575	1,662,538
Total Loans and Leases	1,640,887	1,676,073
Non-Accrual Loans and Leases that are Current	1,351	412
Consumer | Home Equity | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	914	3,949
Consumer | Home Equity | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	703	2,280
Consumer | Home Equity | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	3,519	4,125
Consumer | Automobile
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	0	0
Total Past Due and Non-Accrual	2,459	21,170
Current	698,243	699,116
Total Loans and Leases	700,702	720,286
Non-Accrual Loans and Leases that are Current	0	0
Consumer | Automobile | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	2,027	16,067
Consumer | Automobile | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	299	4,154
Consumer | Automobile | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	133	949
Consumer | Other
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Non-Accrual	0	0
Total Past Due and Non-Accrual	3,306	7,065
Current	448,323	482,541
Total Loans and Leases	451,629	489,606
Non-Accrual Loans and Leases that are Current	0	0
Consumer | Other | 30 - 59 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	1,946	3,498
Consumer | Other | 60 - 89 Days Past Due
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	1,064	2,074
Consumer | Other | Past Due 90 Days or More
Aging Analysis of Accruing and Non-Accruing Loans and Leases
Days Past Due	$ 296	$ 1,493