EARNINGS PER SHARE (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Numerator:
Net Income	$ 37,350	$ 18,937
Denominator:
Weighted average basic shares (in shares)	31,426	31,407
Dilutive potential common shares (in shares)	834	942
Weighted average fully diluted shares (in shares)	32,260	32,349
Earnings per share:
Basic (in dollars per share)	$ 1.19	$ 0.60
Diluted (in dollars per share)	$ 1.16	$ 0.59
Outstanding common stock equivalents having no dilutive effect (in shares)	88	22