Loans and the Allowance for Loan Losses (Details) - Aging analysis - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Financing Receivable, Past Due [Line Items]
Nonaccrual	$ 62,373	$ 49,481
Total Past Due and Nonaccrual	159,486	58,797
Current	5,854,333	5,059,497
Gross Loans	6,013,819	5,118,294
Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	29,984	31,455
Total Past Due and Nonaccrual	40,232	34,801
Current	1,199,995	1,094,860
Gross Loans	1,240,227	1,129,661
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	8,314	8,338
Total Past Due and Nonaccrual	77,282	10,808
Current	3,630,109	3,031,151
Gross Loans	3,707,391	3,041,959
Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	18,205	6,773
Total Past Due and Nonaccrual	26,126	6,773
Current	650,710	616,553
Gross Loans	676,836	623,326
Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	5,819	2,915
Total Past Due and Nonaccrual	15,791	6,415
Current	371,609	313,605
Gross Loans	387,400	320,020
Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual	51
Total Past Due and Nonaccrual	55
Current	1,910	3,328
Gross Loans	1,965	3,328
30 - 59 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	90,944	5,576
30 - 59 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	6,229	239
30 - 59 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	68,291	1,980
30 - 59 Days Past Due [Member] | Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	7,921
30 - 59 Days Past Due [Member] | Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	8,501	3,357
30 - 59 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	2
60 - 89 Days Past Due [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	645	633
60 - 89 Days Past Due [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
60 - 89 Days Past Due [Member] | Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual		490
60 - 89 Days Past Due [Member] | Commercial Construction Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual
60 - 89 Days Past Due [Member] | Residential Real Estate Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	643	143
60 - 89 Days Past Due [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	2
90 Days or Greater Past Due and Still Accruing [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due and Nonaccrual	5,524	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	4,019	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	677
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	828
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