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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Numerator
Numerator for basic and diluted earnings per share - income from continuing operations available to common stockholders	$ 8,821	$ 15,008	$ 15,801	$ 23,292
Denominator
Denominator for basic earnings per share - weighted average shares outstanding (in shares)	50,165	50,436	50,133	50,636
Effect of dilutive securities - stock options and other stock units (in shares)	197	154	237	247
Denominator for diluted earnings per share - adjusted weighted average shares outstanding (in shares)	50,362	50,590	50,370	50,883
Earnings per share:
Basic (in dollars per share)	$ 0.18	$ 0.30	$ 0.32	$ 0.46
Diluted (in dollars per share)	$ 0.18	$ 0.30	$ 0.31	$ 0.46