Loans and the Allowance for Loan and Lease Losses (Details) - Composition of loan portfolio (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Dec. 31, 2014
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 2,642,523	$ 2,539,531
Net deferred loan fees	(1,784)	(890)
Total loans receivable	2,640,739	2,538,641
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	562,931	499,816
Commercial Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	1,668,310	1,634,510
Construction Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	181,056	167,359
Residential Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	226,645	234,967
Consumer Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans	$ 3,581	$ 2,879