Earnings Per Share - Computation of Basic and Diluted Earnings Per Share for Continuing Operations (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Numerator:
Income from continuing operations	$ 6,685	$ 6,446	$ 26,188	$ 24,472
Basic
Weighted average common shares outstanding	49,464	48,273	48,809	48,228
Diluted
Stock options	868	769	829	815
Restricted stock awards	224	258	290	338
Contingent shares	118	134	118	134
Convertible senior subordinated notes	1,350	2,618	1,181	2,837
Diluted weighted average common shares outstanding	52,024	52,052	51,227	52,352
Basic earnings per share from continuing operations	$ 0.14	$ 0.13	$ 0.54	$ 0.51
Diluted earnings per share from continuing operations	$ 0.13	$ 0.12	$ 0.51	$ 0.47