Summary of Significant Accounting Policies (Earnings Per Share) (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Accounting Policies [Abstract]
Net income	$ 14,931	$ 30,890
Basic earnings per share:
Income available to common stockholders, basic	$ 14,931	$ 30,890
Weighted average common shares outstanding, basic (in shares)	64,386,138	64,766,619
Income available to common stockholders, per share amount, basic (usd per share)	$ 0.23	$ 0.48
Dilutive shares (in shares)	71,125	146,119
Diluted earnings per share:
Income available to common stockholders, diluted	$ 14,931	$ 30,890
Weighted average common shares outstanding, diluted (in shares)	64,457,263	64,912,738
Income available to common stockholders, per share amount, diluted (usd per share)	$ 0.23	$ 0.48