Equity - Capital Purchase Program Warrants (Details) - $ / shares	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018
Class of Warrant or Right [Line Items]
Warrants outstanding	1,000,000.0		1,900,000
Class of Warrant or Right, Exercise Price of Warrants or Rights	$ 8.791		$ 8.836
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	1.1		1.1
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	1,000,000,000.0
Warrant [Member]
Class of Warrant or Right [Line Items]
Warrants Exercised	900,000	100,000