Basis of Presentation and Consolidation - Computation of Basic and Diluted 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
Numerator
Numerator for basic and diluted earnings per share - income from continuing operations available to common stockholders	$ 29,344	$ 53,713	$ 45,146	$ 77,005
Denominator
Denominator for basic earnings per share - weighted average shares outstanding (in shares)	50,179	50,065	50,148	50,443
Effect of dilutive securities - stock options and other stock units (in shares)	179	214	218	235
Denominator for diluted earnings per share - adjusted weighted average shares outstanding (in shares)	50,358	50,279	50,366	50,678
Earnings per share:
Basic (in dollars per share)	$ 0.58	$ 1.07	$ 0.90	$ 1.53
Diluted (in dollars per share)	$ 0.58	$ 1.07	$ 0.90	$ 1.52