Earnings Per Share - Schedule of Calculation of Basic and Diluted Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Earnings per common share - Basic
Net income	$ 384,155	$ 370,249	$ 142,413
Preferred stock dividends	(12,602)	(9,095)	(9,095)
Dividends and undistributed earnings allocated to unvested restricted shares	(3,559)	(3,583)	(1,210)
Earnings allocated to common shareholders - basic	$ 367,994	$ 357,571	$ 132,108
Weighted average common shares outstanding (in shares)	52,826	55,008	50,640
Earnings per common share - basic (in usd per share)	$ 6.97	$ 6.50	$ 2.61
Earnings per common share - Diluted
Earnings allocated to common shareholders - basic	$ 367,994	$ 357,571	$ 132,108
Dividends and undistributed earnings allocated to unvested restricted shares	6	(49)	(1)
Earnings allocated to common shareholders - diluted	$ 368,000	$ 357,522	$ 132,107
Weighted average common shares outstanding (in shares)	52,826	55,008	50,640
Dilutive potential common shares (in shares)	327	352	352
Weighted average common shares outstanding - diluted (in shares)	53,153	55,360	50,992
Earnings per common share - diluted (in usd per share)	$ 6.92	$ 6.46	$ 2.59