Condensed Consolidated Statements of Equity (USD $) In Thousands, except Share data, unless otherwise specified	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Parent [Member]	Noncontrolling Interest [Member]	Total
Balance at December 31, 2010 at Dec. 31, 2010
Stock-based compensation		$ 6,672			$ 6,672		$ 6,672
Exercise of options by employees and directors (in Shares)							0
Increase in noncontrolling interest due to sale of equity interest in OPC LLC		2,343			2,343	1,499	3,842
Cash dividend paid			(5,924)		(5,924)		(5,924)
Increase in noncontrolling interest in ORTP LLC		2,343			2,343	1,499	3,842
Net income (loss)			(43,056)		(43,056)	332	(42,724)
Other comprehensive income (loss), net of related taxes:
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge (net of related tax)				(212)	(212)		(212)
Change in fair value of marketable securities available-for-sale				(237)	(237)		(237)
Balance at Dec. 31, 2011	46	725,746	172,331	595	898,718	7,926	906,644
Balance (in Shares) at Dec. 31, 2011	45,431,000
Stock-based compensation		6,394			6,394		6,394
Exercise of options by employees and directors (in Shares)							0
Cash paid to noncontrolling interest						(1,244)	(1,244)
Cash dividend paid			(3,636)		(3,636)		(3,636)
Net income (loss)			(213,021)		(213,021)	414	(212,607)
Other comprehensive income (loss), net of related taxes:
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge (net of related tax)				(190)	(190)		(190)
Change in fair value of marketable securities available-for-sale				246	246		246
Balance at Dec. 31, 2012	46	732,140	(44,326)	651	688,511	7,096	695,607
Balance at December 31, 2010 (in Shares) at Dec. 31, 2012	45,431,000
Stock-based compensation		6,262			6,262		6,262
Exercise of options by employees and directors		529			529		529
Exercise of options by employees and directors (in Shares)	30,000						39
Cash paid to noncontrolling interest						(669)	(669)
Increase in noncontrolling interest due to sale of equity interest in OPC LLC						5,151	5,151
Cash dividend paid		(3,636)			(3,636)		(3,636)
Increase in noncontrolling interest in ORTP LLC						5,151	5,151
Net income (loss)			41,238		41,238	793	42,031
Other comprehensive income (loss), net of related taxes:
Amortization of unrealized gains in respect of derivative instruments designated for cash flow hedge (net of related tax)				(164)	(164)		(164)
Balance at Dec. 31, 2013	$ 46	$ 735,295	$ (3,088)	$ 487	$ 732,740	$ 12,371	$ 745,111
Balance (in Shares) at Dec. 31, 2013	45,461,000