Summary of Significant Accounting Policies - Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Accounting Policies [Abstract]
Net income available to common stockholders	$ 237,828	$ 215,713	$ 92,940
Average common shares outstanding (in shares)	98,351	92,268	69,385
Average potential dilutive common shares (in shares)	446	562	468
Average diluted common shares (in shares)	98,797	92,830	69,853
Basic earnings per share (in dollars per share)	$ 2.42	$ 2.34	$ 1.34	[1]
Diluted earnings per share (in dollars per share)	$ 2.41	$ 2.32	$ 1.33	[1]

[1] Per share amounts for the year ended 2017 have been restated to reflect the effect of the two-for-one stock split on February 8, 2018.