Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash flows from operating activities:
Net income	$ 99,201	$ 47,872
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	80,463	74,836
Amortization of premium from senior unsecured bonds	(230)	(230)
Accretion of asset retirement obligation	1,140	1,122
Stock-based compensation	3,077	4,308
Amortization of deferred lease income	(2,014)	(2,014)
Income attributable to sale of tax benefits, net of interest expense	(13,068)	(10,130)
Equity in losses of investees	4,893	1,210
Mark-to-market of derivative instruments	3,906	(4,467)
Loss on disposal of property, plant and equipment	531	(7,628)
Write-off of unsuccessful exploration activities	359	8,107
Gain on severance pay fund asset	(102)	798
Gain on sale of a subsidiary		(7,628)
Deferred income tax provision	(34,613)	13,071
Liability for unrecognized tax benefits	(399)	656
Deferred lease revenues	(221)	(188)
Other	484	(181)
Changes in operating assets and liabilities, net of amounts acquired:
Receivables	(2,879)	21,624
Costs and estimated earnings in excess of billings on uncompleted contracts	13,334	6,433
Inventories	335	4,952
Prepaid expenses and other	(3,033)	(5,163)
Deposits and other	(294)	279
Accounts payable and accrued expenses	(21,904)	(10,868)
Due from/to related entities, net	451	(64)
Billings in excess of costs and estimated earnings on uncompleted contracts	(2,108)	37,407
Liabilities for severance pay	(1,573)	(1,857)
Other long-term liabilities	(2,259)	(527)
Due from/to Parent	(513)	(588)
Net cash provided by operating activities	122,965	178,770
Cash flows from investing activities:
Cash acquired in organizational restructuring and share exchange with parent (Note 1)	15,391
Net change in restricted cash, cash equivalents and marketable securities	22,725	(76,387)
Cash received from sale of a subsidiary		35,250
Capital expenditures	(117,588)	(122,587)
Cash grant received from the U.S. Treasury under Section 1603 of the ARRA		27,427
Investment in unconsolidated companies		(631)
Decrease in severance pay fund asset, net of payments made to retired employees	2,934	1,493
Net cash used in investing activities	(76,538)	(135,435)
Cash flows from financing activities:
Proceeds from sale of membership interests to noncontrolling interest, net of transaction costs	156,761
Proceeds from long-term loans, net of transaction costs	42,000	140,000
Proceeds from exercise of options by employees	4,612	741
Payment for acquisition of noncontrolling interest in Crump		(1,490)
Purchase of OFC Senior Secured Notes	(30,638)	(12,860)
Proceeds from revolving credit lines with banks	598,800	2,400,683
Repayment of revolving credit lines with banks	(619,100)	(2,484,600)
Cash received from non-controlling interest	1,654	2,234
Repayments of long-term debt	(40,532)	(80,223)
Cash paid to non-controlling interest	(13,863)	(9,215)
Cash paid for interest rate cap		(1,505)
Deferred debt issuance costs	(5,038)	(4,724)
Cash dividends paid	(9,772)	(7,279)
Net cash provided by (used in) financing activities	84,884	(58,238)
Net change in cash and cash equivalents	131,311	(14,903)
Cash and cash equivalents at beginning of period	40,230	57,354
Cash and cash equivalents at end of period	171,541	42,451
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	$ 18,930	$ (5,221)