Equity - Capital Purchase Program Warrants (Details) - $ / shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Class of Warrant or Right [Line Items]
Warrants outstanding	2.1		2.1		2.2
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 8.886		$ 8.886		$ 8.999
Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants Exercised	0.1	0.6	0.2	1.7