Loans and the Allowance for Loan Losses (Details) - Aging analysis - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Nonaccrual	$ 65,494	$ 49,481
Total Past Due and Nonaccrual	86,015	58,797
Current	6,177,245	5,059,497
Gross Loans	6,263,260	5,118,294
Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	33,108	31,455
Total Past Due and Nonaccrual	36,786	34,801
Current	1,594,648	1,094,860
Gross Loans	1,631,434	1,129,661
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	9,378	8,338
Total Past Due and Nonaccrual	18,830	10,808
Current	3,653,632	3,031,151
Gross Loans	3,672,462	3,041,959
Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	17,727	6,773
Total Past Due and Nonaccrual	19,330	6,773
Current	594,782	616,553
Gross Loans	614,112	623,326
Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,281	2,915
Total Past Due and Nonaccrual	11,069	6,415
Current	332,307	313,605
Gross Loans	343,376	320,020
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
Current	1,876	3,328
Gross Loans	1,876	3,328
30 - 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	1,891	5,576
30 - 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	119	239
30 - 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual		1,980
30 - 59 Days Past Due [Member] | Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	338
30 - 59 Days Past Due [Member] | Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	1,434	3,357
30 - 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
60 - 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	5,822	633
60 - 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	403
60 - 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	3,927	490
60 - 89 Days Past Due [Member] | Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	1,265
60 - 89 Days Past Due [Member] | Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	227	143
60 - 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	12,808	3,107
90 Days or Greater Past Due and Still Accruing [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	3,156	3,107
90 Days or Greater Past Due and Still Accruing [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	5,525
90 Days or Greater Past Due and Still Accruing [Member] | Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
90 Days or Greater Past Due and Still Accruing [Member] | Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	4,127
90 Days or Greater Past Due and Still Accruing [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual