Loans and Leases - Loan Mark (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	$ 559,815	$ 833,352
Acquired Loans, Remaining Loan Mark	(17,912)	(34,790)
Acquired loans, recorded investment	541,903	798,562
Commercial mortgage
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	339,241	412,263
Acquired Loans, Remaining Loan Mark	(9,627)	(11,213)
Acquired loans, recorded investment	329,614	401,050
Home equity lines and loans
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	28,212	37,944
Acquired Loans, Remaining Loan Mark	(2,367)	(2,952)
Acquired loans, recorded investment	25,845	34,992
Residential mortgage
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	86,111	101,523
Acquired Loans, Remaining Loan Mark	(2,778)	(3,572)
Acquired loans, recorded investment	83,333	97,951
Construction
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	6,780	86,081
Acquired Loans, Remaining Loan Mark	(294)	(1,893)
Acquired loans, recorded investment	6,486	84,188
Commercial and industrial
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	72,948	141,960
Acquired Loans, Remaining Loan Mark	(2,007)	(11,952)
Acquired loans, recorded investment	70,941	130,008
Consumer
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	2,828	3,051
Acquired Loans, Remaining Loan Mark	(113)	(44)
Acquired loans, recorded investment	2,715	3,007
Leases
Loans and Leases Receivable Disclosure [Line Items]
Acquired loans, outstanding principal	23,695	50,530
Acquired Loans, Remaining Loan Mark	(726)	(3,164)
Acquired loans, recorded investment	$ 22,969	$ 47,366