Fair Value of Financial Instruments (Details) (USD $)	Dec. 31, 2013	Dec. 31, 2012
Assets:
Marketable securities	$ 49,211,000	$ 48,206,000
Long term investments	8,756,000
Liabilities:
Derivative liabilities	12,644,000	251,000
Quoted Prices in Active Markets (Level 1)
Assets:
Cash and cash equivalents	32,980,000	31,561,000
Total assets at fair value	32,980,000	31,561,000
Significant Other Observable Inputs (Level 2)
Assets:
Cash and cash equivalents		8,741,000
Marketable securities	49,211,000	48,206,000
Long term investments	8,756,000
Marketable securities - restricted (SERP)	305,000	279,000
Total assets at fair value	58,272,000	57,226,000
Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liabilities	12,644,000	251,000
Total Carrying Value
Assets:
Cash and cash equivalents	32,980,000	40,302,000
Marketable securities	49,211,000	48,206,000
Long term investments	8,756,000
Marketable securities - restricted (SERP)	305,000	279,000
Total assets at fair value	91,252,000	88,787,000
Liabilities:
Derivative liabilities	$ 12,644,000	$ 251,000