Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Cash flows from operating activities:
Net income	$ 30,945	$ 10,267
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	26,181	25,639
Amortization of premium from senior unsecured bonds	(77)	(77)
Accretion of asset retirement obligation	406	372
Stock-based compensation	842	1,127
Amortization of deferred lease income	(671)	(671)
Income attributable to sale of tax benefits, net of interest expense	(3,475)	(4,044)
Equity in losses of investees	937	775
Mark-to-market of derivative instruments	(162)	4,129
Write-off of unsuccessful exploration activities	557	174
Gain on severance pay fund asset	(564)	140
Deferred income tax provision	6,643	4,054
Liability for unrecognized tax benefits	254	(321)
Deferred lease revenues	88	(74)
Changes in operating assets and liabilities, net of amounts acquired:
Receivables	(21,925)	(6,201)
Costs and estimated earnings in excess of billings on uncompleted contracts	(4,777)	20,367
Inventories	1,279	(356)
Prepaid expenses and other	(1,808)	1,189
Deposits and other	80	(79)
Accounts payable and accrued expenses	(4,846)	(4,903)
Billings in excess of costs and estimated earnings on uncompleted contracts	(2,975)	33,137
Liabilities for severance pay	(205)	(1,900)
Other long-term liabilities	$ 317	916
Due from/to Parent		(513)
Net cash provided by operating activities	$ 27,044	83,147
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	$ (14,626)	(22,282)
Capital expenditures	(31,031)	(42,386)
Decrease in severance pay fund asset, net of payments made to retired employees	1,037	2,020
Net cash used in investing activities	(44,620)	(47,257)
Cash flows from financing activities:
Proceeds from exercise of options by employees	4,195	2,704
Proceeds from revolving credit lines with banks	49,700	489,900
Repayment of revolving credit lines with banks	(40,700)	(479,600)
Cash received from non-controlling interest	1,972	1,654
Repayments of long-term debt	(11,631)	(10,494)
Cash paid to non-controlling interest	(6,317)	(3,503)
Deferred debt issuance costs	(1,592)	(2,159)
Cash dividends paid	(15,472)	(3,898)
Net cash provided by (used in) financing activities	(19,845)	(5,396)
Net change in cash and cash equivalents	(37,421)	30,494
Cash and cash equivalents at beginning of period	185,919	40,230
Cash and cash equivalents at end of period	148,498	70,724
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	(5,296)	$ (118)
Accrued liabilities related to financing activities	$ 3,768