Loans and Leases (Narrative) (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Receivables [Abstract]
Deferred loan fees	$ 42,800	$ 26,300	$ 20,200
Discounts on acquired loans	131,900	236,600
Total loans pledged to secure borrowings	9,400,000
Outstanding contractual unpaid principal balance of non-covered purchased impaired loans	599,200	770,900
Receivables Acquired with Deteriorated Credit Quality [Member]
Financing Receivable, Allowance for Credit Losses [Line Items]
Loans acquired with deteriorated credit quality	$ 448,088	$ 562,900	$ 636,019