NET INCOME PER SHARE (DILUTED SHARES TABLE) (DETAILS) - shares shares in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Weighted Average Number of Shares Outstanding Reconciliation [Abstract]
Shares used in basic earnings per share calculation	45,838	47,081	45,816	47,771
Effect of dilutive securities:
Stock options	10	6	9	11
Restricted stock units	517	214	513	292
Performance-based restricted stock units	2	14	10	15
Total effects of dilutive securities	529	234	532	318
Shares used in dilutive earnings per share calculation	46,367	47,315	46,348	48,089