NET (LOSS) INCOME PER SHARE (Schedule of Basic and Diluted Net Income Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share Reconciliation [Line Items]
Net (loss) income	$ (23,990)	$ 12,303	$ (39,493)	$ 13,668
Basic net (loss) income per share:
Weighted-average common shares outstanding (in shares)	72,413	75,601	71,980	78,620
Basic net income per share attributable to common stockholders (in USD per share)	$ (0.33)	$ 0.16	$ (0.55)	$ 0.17
Diluted net (loss) income per share:
Weighted-average common shares outstanding (in shares)	72,413	75,601	71,980	78,620
Number of shares used in diluted calculation (in shares)	72,413	78,530	71,980	81,742
Diluted net income per share attributable to common stockholders (in USD per share)	$ (0.33)	$ 0.16	$ (0.55)	$ 0.17
Stock options
Diluted net (loss) income per share:
Incremental common shares (in shares)	0	2,412	0	2,427
Restricted stock units
Diluted net (loss) income per share:
Incremental common shares (in shares)	0	510	0	691
Employee stock purchase program
Diluted net (loss) income per share:
Incremental common shares (in shares)	0	7	0	4