Shareholders' Equity - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2019	Jun. 30, 2018	Apr. 01, 2019	Dec. 31, 2018	Mar. 11, 2016
Stockholders Equity [Line items]
Capital conservation buffer rate	2.50%		2.50%			1.875%
Stock Repurchase Program
Stockholders Equity [Line items]
Repurchase shares of common stock			3,200,000
Repurchase shares of common stock, value			$ 100.0
Stock Repurchase Program | Common Stock [Member]
Stockholders Equity [Line items]
Amount of stock authorized for repurchase							$ 100.0
Repurchase shares of common stock		1,200,000	1,600,000	243,000
Repurchase shares of common stock, value		$ 36.9	$ 49.9	$ 7.9
New Stock Repurchase Program [Member]
Stockholders Equity [Line items]
Amount of stock authorized for repurchase					$ 100.0
New Stock Repurchase Program [Member] | Common Stock [Member]
Stockholders Equity [Line items]
Repurchase shares of common stock	398,000
Repurchase shares of common stock, value	$ 13.0