Condensed Consolidated Statements of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Cash flows from operating activities:
Net income	$ 20,533	$ 16,747
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	45,884	49,757
Amortization of premium from senior unsecured bonds	(153)	(154)
Accretion of asset retirement obligation	758	834
Stock-based compensation	2,857	3,127
Amortization of deferred lease income	(1,343)	(1,343)
Income attributable to sale of tax benefits, net of interest expense	(4,578)	(1,900)
Equity in (income) losses of investees	(9)	297
Mark-to-market of derivative instruments	2,370
Write-off of unsuccessful exploration activities		1,919
Loss (gain) on severance pay fund asset	(403)	364
Gain on sale of a subsidiary	(3,646)
Deferred income tax provision	9,634	5,256
Liability for unrecognized tax benefits	1,074	837
Deferred lease revenues	(117)	74
Other	(819)
Changes in operating assets and liabilities, net of amounts acquired:
Receivables	(17,748)	10,310
Costs and estimated earnings in excess of billings on uncompleted contracts	(6,710)	(6,085)
Inventories	2,763	(5,578)
Prepaid expenses and other	(4,173)	(5,795)
Deposits and other	(2,840)	(3,560)
Accounts payable and accrued expenses	(8,827)	14,901
Due from/to related entities, net	(46)	(42)
Billings in excess of costs and estimated earnings on uncompleted contracts	(14,438)	(7,832)
Liabilities for severance pay	309	310
Other long-term liabilities	(225)	(464)
Due from/to Parent	(157)	99
Net cash provided by operating activities	19,950	72,079
Cash flows from investing activities:
Marketable securities, net		13,280
Short-term deposit	(11)
Net change in restricted cash, cash equivalents and marketable securities	(8,975)	(22,271)
Cash received from sale of a subsidiary	7,699
Capital expenditures	(102,019)	(129,879)
Cash grant received		72,252
Investment in unconsolidated companies	(924)	(323)
Increase (decrease) in severance pay fund asset, net of payments made to retired employees	1,061	(87)
Net cash used in investing activities	(103,169)	(67,028)
Cash flows from financing activities:
Proceeds from long-term loans	45,000
Proceeds from the sale of limited liability company interest in ORTP, LLC, net of transaction costs	31,508
Purchase of OFC Senior Secured Notes	(11,888)
Proceeds from revolving credit lines with banks	1,354,761	1,083,754
Repayment of revolving credit lines with banks	(1,348,120)	(1,094,434)
Repayments of long-term debt	(18,787)	(16,987)
Cash paid to non-controlling interest	(6,990)	(7,497)
Deferred debt issuance costs		(1,270)
Cash dividends paid		(1,819)
Net cash provided by (used in) financing activities	45,484	(38,253)
Net change in cash and cash equivalents	(37,735)	(33,202)
Cash and cash equivalents at beginning of period	66,628	99,886
Cash and cash equivalents at end of period	28,893	66,684
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	4,063	(13,749)
Accrued liabilities related to financing activities	$ (1,347)