FAIR VALUE OF CERTAIN FINANCIAL ASSETS AND LIABILITIES (Details 4) (USD $)				12 Months Ended				6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2014 Auction rate securities	Dec. 31, 2013 2011 ARS Agreement	Dec. 31, 2012 2011 ARS Agreement	Dec. 31, 2011 2011 ARS Agreement	Jun. 30, 2011 2011 ARS Agreement	Jun. 30, 2014 2011 ARS Agreement Subsequent event	Jun. 30, 2014 Put option related to auction rate securities	Jun. 30, 2014 2011 Put Option	Jun. 30, 2013 2011 Put Option	Jun. 30, 2014 2011 Put Option	Jun. 30, 2013 2011 Put Option	Oct. 01, 2013 2011 Put Option Maximum	Jul. 01, 2013 2011 Put Option Maximum
ARS Agreement
Face value of investments			$ 13,800,000
Impairment of investments, trading securities			1,000,000
Amortized Cost	505,651,000	412,039,000	12,800,000
Trading auction rate securities, in short-term and long-term investments			12,800,000
Amount of securities of par value							24,500,000							1,000,000	1,000,000
Redemption of investment securities through the exercise of the put option									3,400,000
Redemption of investment securities at par through normal market channels				2,300,000	1,300,000	3,700,000		8,600,000
Fair market value of investments										1,000,000		1,000,000
Resulted (loss) gain on revaluation of investment securities included in other income (expense)										$ 12,000	$ 100,000	$ 13,000	$ 2,600,000