Acquisitions - The Banc Ed Corp. (Details) - The Banc Ed Corp. - USD ($) $ / shares in Units, $ in Millions		3 Months Ended	9 Months Ended
	Aug. 21, 2018	Sep. 30, 2018	Sep. 30, 2018
Non-interest expense
Merger agreement
Business acquisition expenses		$ 0.2	$ 0.2
Subject to customary closing conditions
Merger agreement
Total consolidated assets		1,800.0	1,800.0
Total loans		914.5	914.5
Total deposits		$ 1,600.0	$ 1,600.0
Per share cash consideration entitled (in dollars per share)	$ 111.53
Number of common shares issued for acquisition	8.2067
Total consideration, stock, percentage	70.00%
Total consideration, cash, percentage	30.00%