Consolidated Statement Of Stockholders’ Equity (Dollar amounts in thousands) (USD $) In Thousands, except Share data	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 at Dec. 31, 2009	$ 295	$ 80	$ 66,082	$ (58,190)	$ 288,386	$ 5,130	$ 301,783
Balance at (in Shares) at Dec. 31, 2009	29,519,757	8,039,524		2,421,617
Exercise of options (Note L)	3	0	1,244	0	0	0	1,247
Exercise of options (Note L) (in Shares)	241,999	0		0			(241,999)
Stock-based compensation (Notes A18 and L)	0	0	1,738	0	0	0	1,738
Net loss for the year	0	0	0	0	(68,212)	0	(68,212)
Foreign currency translation (Note A10)	0	0	0	0	0	(2,129)	(2,129)
Net unrealized gain (loss) on hedge derivatives (Notes A12 and F)	0	0	0	0	0	416	416
Net unrealized gain (loss) on investments available for sale and restricted investments available for sale (Notes B and C)	0	0	0	0	0	70	70
Balance at at Dec. 31, 2010	298	80	69,064	(58,190)	220,174	3,487	234,913
Balance at (in Shares) at Dec. 31, 2010	29,761,756	8,039,524		2,421,617
Exercise of options (Note L)	2	0	1,060	0	0	0	1,062
Exercise of options (Note L) (in Shares)	220,498	0		0			(220,498)
Stock-based compensation (Notes A18 and L)	0	0	851	0	0	0	851
Net loss for the year	0	0	0	0	(70,471)	0	(70,471)
Foreign currency translation (Note A10)	0	0	0	0	0	(1,255)	(1,255)
Net unrealized gain (loss) on hedge derivatives (Notes A12 and F)	0	0	0	0	0	961	961
Net unrealized gain (loss) on investments available for sale and restricted investments available for sale (Notes B and C)	0	0	0	0	0	(92)	(92)
Balance at at Dec. 31, 2011	300	80	70,975	(58,190)	149,703	3,101	165,969
Balance at (in Shares) at Dec. 31, 2011	29,982,254	8,039,524		2,421,617
Exercise of options (Note L)	0	0	5	0	0	0	5
Exercise of options (Note L) (in Shares)	7,334	0		0			(7,334)
Stock-based compensation (Notes A18 and L)	0	0	1,031	0	0	0	1,031
Net loss for the year	0	0	0	0	(34,779)	0	(34,779)
Foreign currency translation (Note A10)	0	0	0	0	0	656	656
Net unrealized gain (loss) on hedge derivatives (Notes A12 and F)	0	0	0	0	0	(1,266)	(1,266)
Net unrealized gain (loss) on investments available for sale and restricted investments available for sale (Notes B and C)	0	0	0	0	0	(2)	(2)
Balance at at Dec. 31, 2012	$ 300	$ 80	$ 72,011	$ (58,190)	$ 114,924	$ 2,489	$ 131,614
Balance at (in Shares) at Dec. 31, 2012	29,989,588	8,039,524		2,421,617