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
	Mar. 31, 2019	Mar. 31, 2018
Numerator
Numerator for basic and diluted earnings per share - income from continuing operations available to common stockholders	$ 6,979	$ 8,285
Denominator
Denominator for basic earnings per share - weighted average shares outstanding (in shares)	50,100	50,838
Effect of dilutive securities - stock options and other stock units (in shares)	278	341
Denominator for diluted earnings per share - adjusted weighted average shares outstanding (in shares)	50,378	51,179
Earnings per share:
Basic (in dollars per share)	$ 0.14	$ 0.16
Diluted (in dollars per share)	$ 0.14	$ 0.16