Earnings Per Share and Weighted-Average Shares Outstanding - Calculation of Basic Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic earnings per share:
Net income available to common stockholders	[1]	$ 85,475	$ 66,563	$ 118,599	$ 87,107
Basic weighted-average shares of common stock outstanding		177,020	155,152	178,122	155,348
Basic earnings per share		$ 0.48	$ 0.43	$ 0.67	$ 0.56

[1] Includes a reduction for dividends on preferred stock or units in the amount of $3.2 million and $1.7 million for the three months ended September 30, 2019 and 2018, respectively, and $9.7 million and $1.9 million for the nine months ended September 30, 2019 and 2018, respectively.