Consolidated Statements Of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash flows from operating activities:
Net income (loss)	$ (206,016)	$ (42,724)	$ 37,228
Adjustments to reconcile net income or loss to net cash provided by operating activities:
Depreciation and amortization	102,340	96,398	86,761
Amortization of premium from senior unsecured bonds	(307)	(256)
Accretion of asset retirement obligation	1,701	1,593	1,249
Stock-based compensation	6,394	6,672	7,377
Amortization of deferred lease income	(2,685)	(2,685)	(2,685)
Income attributable to sale of tax benefits, net of interest expense	(4,003)	(4,315)	(3,523)
Equity in income (losses) of investees	442	959	(998)
Impairment of auction rate securities		205	137
Loss on disposal of property, plant and equipment			1,245
Write-off of unconsolidated investment	2,114
Write-off of unsuccessful exploration activities	2,639		3,050
Impairment charge	236,377
Return on investment in unconsolidated investments			3,734
Loss (gain) on severance pay fund asset	(931)	588	(1,889)
Premium from issuance of senior unsecured bonds		1,957
Gain on sale of a subsidiary			(6,350)
Gain on acquisition of controlling interest			(36,928)
Deferred income tax provision (benefit)	(11,327)	38,061	(10,139)
Liability for unrecognized tax benefits	1,405	444	500
Deferred lease revenues	128	376	1,082
Changes in operating assets and liabilities, net of amounts acquired:
Receivables	(3,623)	1,979	1,259
Costs and estimated earnings in excess of billings on uncompleted contracts	(5,647)	2,180	8,894
Inventories	(8,128)	(3)	2,948
Prepaid expenses and other	(15,472)	(3,743)	(2,595)
Deposits and other	(12,746)	(710)	(164)
Accounts payable and accrued expenses	11,414	6,646	9,695
Due from/to related entities, net	(86)	16	(89)
Billings in excess of costs and estimated earnings on uncompleted contracts	(7,696)	29,951	(198)
Liabilities for severance pay	2,340	(159)	2,610
Other long-term liabilities	895	(708)	(540)
Due from/to Parent	(51)	12	(268)
Net cash provided by operating activities	89,471	132,734	101,403
Cash flows from investing activities:
Return of investment in unconsolidated investments			3,516
Marketable securities, net	18,763	(17,534)
Short-term deposit	(3,010)
Net change in restricted cash, cash equivalents and marketable securities	(1,016)	(50,614)	17,536
Cash received from sale of a subsidiary			19,594
Capital expenditures	(233,020)	(269,677)	(283,313)
Cash grant received	119,199		108,286
Investment in unconsolidated companies	(1,390)	(472)	(2,715)
Cash paid for acquisition of controlling interest in a subsidiary, net of cash acquired			(64,517)
Cash paid for investment in a joint venture		(200)	(100)
Intangible assets acquired		(1,786)	(1,472)
Decrease in severance pay fund asset, net of payments made to retired employees	(316)	(719)	(635)
Net cash used in investing activities	(100,790)	(341,002)	(203,820)
Cash flows from financing activities:
Proceeds from issuance of senior unsecured bonds	1,171	107,447	142,003
Proceeds from long-term loans, net of transaction costs	214,051		20,000
Proceeds from issuance of senior secured notes, net of transaction costs		141,108
Proceeds from the sale of limited liability company interest in OPC LLC, net of transaction costs		24,878
Proceeds from revolving credit lines with banks	2,953,535	891,583	1,159,869
Repayment of revolving credit lines with banks	(3,093,978)	(867,000)	(1,104,403)
Repayments of long-term debt
Parent			(9,600)
Other	(74,502)	(50,130)	(52,242)
Cash paid to non-controlling interest	(15,383)	(14,039)	(3,136)
Deferred debt issuance costs	(3,197)	(2,584)	(1,302)
Cash dividends paid	(3,636)	(5,924)	(12,264)
Net cash provided by (used in) financing activities	(21,939)	225,339	138,925
Net change in cash and cash equivalents	(33,258)	17,071	36,508
Cash and cash equivalents at beginning of year	99,886	82,815	46,307
Cash and cash equivalents at end of year	66,628	99,886	82,815
Cash paid during the year for:
Interest, net of interest capitalized	40,398	33,274	34,587
Income taxes, net	11,570	13,575	7,570
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	(18,813)	13,117	507
Payable related to investment in joint venture			2,400
Increase (decrease) in asset retirement cost and asset retirement obligation	$ (3,696)	$ (212)	$ 1,238