Loans and the Allowance for Loan Losses (Details) - Composition of loan portfolio - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Impaired [Line Items]
Gross loans	$ 5,118,294	$ 4,544,899
Net deferred fees	(4,767)	(3,807)
Total loans receivable	5,113,527	4,541,092
Commercial Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Gross loans	1,129,661	988,758
Commercial Real Estate Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Gross loans	3,041,959	2,778,167
Commercial construction [Member]
Financing Receivable, Impaired [Line Items]
Gross loans	623,326	465,389
Residential Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Gross loans	320,020	309,991
Consumer Portfolio Segment [Member]
Financing Receivable, Impaired [Line Items]
Gross loans	$ 3,328	$ 2,594