Earnings Per Share - Reconciles Numerator and Denominator of Basic and Diluted Earnings Per Share Computations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Numerator for EPS:
Net income (loss)	$ (3,169)	$ 19,882	$ 20,067	$ 20,146	$ 37,293	$ 40,148	$ 36,780	$ 97,587
Less: Preferred stock dividends	(3)			(3)			(8)	(8)
Income (loss) available to common stockholders	$ (3,172)			$ 20,143			$ 36,772	$ 97,579
Denominator for EPS:
Weighted average common shares outstanding (in shares)	31,659			33,649			32,116	34,230
Plus: Assumed conversion of share-based compensation	0			256			61	310
Assumed conversion of preferred stock	0			25			25	25
Weighted average diluted common shares outstanding (in shares)	31,659			33,930			32,202	34,565
Basic earnings (loss) per common share (in dollars per share)	$ (0.10)			$ 0.60			$ 1.14	$ 2.85
Diluted earnings (loss) per common share (in dollars per share)	$ (0.10)			$ 0.59			$ 1.14	$ 2.82