Loans (Carrying amount loans) (Narrative) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Jul. 07, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for loan and lease losses	$ 54,885		$ 54,885			$ 54,324
Provision for loan losses	5,705	$ 5,328	10,235	$ 9,513
Citywide Banks
Accounts, Notes, Loans and Financing Receivable [Line Items]
Gross loans					$ 1,000,000
Estimated fair value of the loans acquired					$ 985,400
2015, 2016 and 2017 Acquisitions
Accounts, Notes, Loans and Financing Receivable [Line Items]
Contractually required payments of loans acquired	22,200		22,200
Estimated fair value of loans acquired	13,100		13,100
Allowance for loan and lease losses	132		132			$ 588
Provision for loan losses	4	$ 126	5	$ 517
Contractually required payments receivable of nonimpaired loans	2,660,000		2,660,000
Estimated fair value of nonimpaired loans acquired	$ 2,590,000		$ 2,590,000