Condensed Consolidated Statements of Cash Flow (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows from operating activities:
Net income	$ 29,906	$ 28,130
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	36,952	36,901
Accretion of asset retirement obligation	772	651
Stock-based compensation	1,989	2,360
Amortization of deferred lease income	0	(775)
Income attributable to sale of tax benefits, net of interest expense	(2,087)	(4,314)
Equity in losses (earnings) of investees	735	(1,047)
Mark-to-market of derivative instruments	(561)	(1,209)
Loss on disposal of property, plant and equipment	88	377
Loss (gain) on severance pay fund asset	535	(330)
Deferred income tax provision	15,123	10,469
Liability for unrecognized tax benefits	(83)	713
Changes in operating assets and liabilities, net of businesses acquired:
Receivables	(25,008)	(1,119)
Costs and estimated earnings in excess of billings on uncompleted contracts	16,060	12,368
Inventories	842	2,018
Prepaid expenses and other	1,211	(2,105)
Change in operating lease right of use asset	784	1,698
Deposits and other	343	26
Accounts payable and accrued expenses	350	(4,271)
Billings in excess of costs and estimated earnings on uncompleted contracts	3,182	(2,894)
Liabilities for severance pay	(543)	406
Change in operating lease liabilities	(734)	0
Other long-term liabilities	(100)	(616)
Net cash provided by operating activities	79,756	77,437
Cash flows from investing activities:
Capital expenditures	(80,375)	(51,303)
Investment in unconsolidated companies	(358)	0
Decrease (increase) in severance pay fund asset, net of payments made to retired employees	(87)	359
Net cash used in investing activities	(80,820)	(50,944)
Cash flows from financing activities:
Proceeds from long-term loans, net of transaction costs	0	91,500
Repayments of commercial paper	(41,725)	0
Proceeds from revolving credit lines with banks	872,900	914,700
Repayment of revolving credit lines with banks	(642,950)	(1,012,800)
Cash received from noncontrolling interest	6,270	3,346
Repayments of long-term debt	(16,416)	(15,757)
Cash paid to noncontrolling interest	(3,279)	(4,459)
Payments under finance lease obligations	(675)	(767)
Deferred debt issuance costs	(416)	(1,223)
Cash dividends paid	(5,614)	(5,579)
Net cash provided by (used in) financing activities	168,095	(31,039)
Effect of exchange rate changes	(365)	(485)
Net change in cash and cash equivalents and restricted cash and cash equivalents	166,666	(5,031)
Cash and cash equivalents and restricted cash and cash equivalents at beginning of period	153,110	177,495
Cash and cash equivalents and restricted cash and cash equivalents at end of period	319,776	172,464
Supplemental non-cash investing and financing activities:
Increase (decrease) in accounts payable related to purchases of property, plant and equipment	(1,436)	153
Right of use assets obtained in exchange for new lease liabilities	$ 1,194	$ 2,154