GAIN (LOSS) ON INVESTMENTS, NET (Details) (USD $)	12 Months Ended			1 Months Ended	3 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Mar. 31, 2011 Common Shares	Jun. 30, 2011 Common Shares	Mar. 14, 2011 Common Shares
Gain (loss) on investments, net
Loss on auction rate securities			$ (5,552,000)
Gain on disposal of investments	2,056,000	22,776,000
Gain (loss) on investments, net	2,056,000	22,776,000	(5,552,000)
Marketable securities by major security type
Investment in available-for-sale equity securities				60,000,000
Number of shares of common stock acquired				1,034,908
Percentage of outstanding common stock acquired						1.366%
Net proceeds from disposal of investment					81,300,000
Net realized gain					$ 21,300,000