EARNINGS PER COMMON SHARE (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended				6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012		Jun. 30, 2013		Jun. 30, 2012
EARNINGS PER COMMON SHARE [Abstract]
Consolidated net income	$ 12,637		$ 9,706		$ 23,479		$ 12,814
Net income per share [Abstract]
Basic (in dollars per share)	$ 0.13		$ 0.10		$ 0.24		$ 0.13
Diluted (in dollars per share)	$ 0.11		$ 0.09		$ 0.21		$ 0.12
Shares used in computing net income per share [Abstract]
Weighted average basic shares outstanding (in shares)	96,122		95,096		96,025		95,054
Dilutive securities [Abstract]
Stock options and unvested RSAs (in shares)	4,380		4,294		4,383		4,202
Stock warrants (in shares)	6,614		6,569		6,564		6,537
Shares issuable upon conversion of convertible notes (in shares)	5,212	[1]	4,554	[1]	5,038	[1]	4,086	[1]
Total dilutive securities (in shares)	16,206		15,417		15,985		14,825
Weighted average diluted shares outstanding (in shares)	112,328		110,513		112,010		109,879
Stock Options [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Shares subject to stock options omitted from the calculation of net income per share as their effect would have been anti-dilutive (in shares)	1,373		345		1,289		224

[1] Shares issuable upon conversion of convertible notes is based on the assumption that the Company would repay the principal of the notes in cash and pay any incremental value in shares of common stock.