Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Cash flows from operating activities:
Net income	$ 25,540	$ 31,102
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	52,559	48,819
Amortization of premium from senior unsecured bonds	(154)	(153)
Accretion of asset retirement obligation	752	743
Stock-based compensation	2,156	2,806
Amortization of deferred lease income	(1,342)	(1,343)
Income attributable to sale of tax benefits, net of interest expense	(6,720)	(7,540)
Equity in losses of investees	1,759	311
Mark-to-market of derivative instruments	4,140	(302)
Loss on disposal of property, plant and equipment	531	(7,628)
Write-off of unsuccessful exploration activities	174	8,107
Gain on severance pay fund asset	(572)	(396)
Gain on sale of a subsidiary		(7,628)
Deferred income tax provision	7,024	8,887
Liability for unrecognized tax benefits	(360)	639
Deferred lease revenues	(148)	(124)
Other	484	(181)
Changes in operating assets and liabilities, net of amounts acquired:
Receivables	(12,775)	19,959
Costs and estimated earnings in excess of billings on uncompleted contracts	20,700	(4,701)
Inventories	529	3,997
Prepaid expenses and other	(300)	(8,738)
Deposits and other	(362)	86
Accounts payable and accrued expenses	(2,600)	(11,094)
Due from/to related entities, net	451
Billings in excess of costs and estimated earnings on uncompleted contracts	25,007	20,282
Liabilities for severance pay	(975)	(47)
Other long-term liabilities	(2,259)	313
Due from/to Parent	(513)	(225)
Net cash provided by operating activities	112,726	103,579
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	(11,622)	(3,012)
Cash received from sale of a subsidiary		35,250
Capital expenditures	(86,142)	(89,125)
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	2,940	1,079
Net cash used in investing activities	(79,433)	(29,012)
Cash flows from financing activities:
Proceeds from sale of membership interests to noncontrolling interest, net of transaction costs	156,761
Proceeds from exercise of options by employees	3,966	392
Purchase of OFC Senior Secured Notes	(30,638)	(12,860)
Proceeds from revolving credit lines with banks	598,800	1,742,383
Repayment of revolving credit lines with banks	(619,100)	(1,729,800)
Cash received from non-controlling interest	1,654	2,234
Repayments of long-term debt	(29,404)	(41,078)
Cash paid to non-controlling interest	(7,418)	(5,398)
Deferred debt issuance costs	(3,649)	(2,671)
Cash dividends paid	(6,830)	(5,003)
Net cash provided by (used in) financing activities	64,142	(51,801)
Net change in cash and cash equivalents	97,435	22,766
Cash and cash equivalents at beginning of period	40,230	57,354
Cash and cash equivalents at end of period	137,665	80,120
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	$ 12,612	$ (7,289)