Consolidated Statement of Stockholders' Equity (USD $)	Common Class A [Member]	Common Class B [Member]	Additional Paid-in Capital [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
BALANCE at Dec. 31, 2008	$ 292,000	$ 81,000	$ 61,412,000	$ (58,190,000)	$ 316,348,000	$ 4,819,000	$ 324,762,000
BALANCE (in Shares) at Dec. 31, 2008	29,218,392	8,059,524		2,421,617
Conversion of shares (Note M)	1,000	(1,000)
Conversion of shares (Note M)	20,000	(20,000)
Exercise of options (Note M)	2,000		929,000				931,000
Exercise of options (Note M) (in Shares)	281,365
Excess income tax benefit of options exercised (Note M)			550,000				550,000
Stock-based compensation (Notes A18 and M)			3,191,000				3,191,000
Net loss for the year					(27,962,000)		(27,962,000)
Foreign currency translation (Note A10)						4,274,000	4,274,000
Net unrealized (loss)/gain on hedge derivatives (Notes A12 and F)						(3,987,000)	(3,987,000)
Net unrealized (loss)/gain on investments available for sale and restricted investments available for sale (Notes B and C)						24,000	24,000
BALANCE at Dec. 31, 2009	295,000	80,000	66,082,000	(58,190,000)	288,386,000	5,130,000	301,783,000
BALANCE (in Shares) at Dec. 31, 2009	29,519,757	8,039,524		2,421,617
Exercise of options (Note M)	3,000		1,244,000				1,247,000
Exercise of options (Note M) (in Shares)	241,999
Stock-based compensation (Notes A18 and M)			1,738,000				1,738,000
Net loss for the year					(68,212,000)		(68,212,000)
Foreign currency translation (Note A10)						(2,129,000)	(2,129,000)
Net unrealized (loss)/gain on hedge derivatives (Notes A12 and F)						416,000	416,000
Net unrealized (loss)/gain on investments available for sale and restricted investments available for sale (Notes B and C)						70,000	70,000
BALANCE at Dec. 31, 2010	298,000	80,000	69,064,000	(58,190,000)	220,174,000	3,487,000	234,913,000
BALANCE (in Shares) at Dec. 31, 2010	29,761,756	8,039,524		2,421,617
Exercise of options (Note M)	2,000		1,060,000				1,062,000
Exercise of options (Note M) (in Shares)	220,498
Stock-based compensation (Notes A18 and M)			851,000				851,000
Net loss for the year					(70,471,000)		(70,471,000)
Foreign currency translation (Note A10)						(1,255,000)	(1,255,000)
Net unrealized (loss)/gain on hedge derivatives (Notes A12 and F)						961,000	961,000
Net unrealized (loss)/gain on investments available for sale and restricted investments available for sale (Notes B and C)						(92,000)	(92,000)
BALANCE at Dec. 31, 2011	$ 300,000	$ 80,000	$ 70,975,000	$ (58,190,000)	$ 149,703,000	$ 3,101,000	$ 165,969,000
BALANCE (in Shares) at Dec. 31, 2011	29,982,254	8,039,524		2,421,617