Equity - Capital Purchase Program, Additional Information (Details) - $ / shares	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Class of Warrant or Right [Line Items]
Warrant exercise price (in USD per share)	$ 8.836	$ 8.999	$ 9.126
Class of Warrant or Right, Number of Securities Called by Each Warrant or Right	1.1	1.0	1.0
Warrant
Class of Warrant or Right [Line Items]
Warrants outstanding (in shares)	1,900,000	2,200,000
Warrants exercised (in shares)	300,000	1,800,000	400,000