Loan and Lease Financings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Receivables [Abstract]
Total loans and leases	$ 4,527,678	$ 4,188,071
Deferred loan and lease costs	3,850	3,780
Direct finance leases:
Rentals receivable	208,295	218,543
Estimated residual value of leased assets	29,638	21,992
Gross investment in lease financing	237,933	240,535
Unearned income	(37,851)	(35,751)
Net investment in lease financing	200,082	204,784
Minimum future lease payments receivable
2018	51,170
2019	44,040
2020	39,030
2021	30,450
2022	27,830
Loans to certain directors, executive officers, and principal shareholders of equity securities of the entity and to their affiliates
Loan to related parties	14,610	$ 31,460
New loans and other additions to related parties	2,300
Repayments and other reductions of loan given to related parties	$ 19,150