Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Operating activities
Net loss	$ (72,538)	$ (59,761)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion and amortization	28,447	29,055
Amortization related to the 2.75% Convertible Notes (Note 14)	2,463	0
Gain on sales of property and equipment, net	(623)	(1,900)
Stock-based compensation	2,398	5,748
Equity in net loss from unconsolidated joint ventures	11,816	20,384
Net income from affiliates	(46)	(1,290)
Non-cash impairment charges (See Note 4)	24,413	0
Changes in assets and liabilities:
Receivables	71,040	103,484
Contract assets, net	22,997	(33,345)
Inventories	(9,880)	(8,238)
Contributions to unconsolidated construction joint ventures	(13,767)	(26,933)
Distributions from unconsolidated construction joint ventures and affiliates	2,939	330
Other assets, net	(12,138)	(11,648)
Accounts payable	(87,979)	(40,588)
Accrued expenses and other current liabilities, net	10,333	(11,662)
Net cash used in operating activities	(20,125)	(36,364)
Investing activities
Proceeds from called marketable securities	20,000	0
Maturities of marketable securities	5,000	0
Purchases of property and equipment	(21,435)	(28,744)
Proceeds from sales of property and equipment	3,865	4,687
Other investing activities, net	(1,528)	(286)
Net cash provided by (used in) investing activities	5,902	(24,343)
Financing activities
Proceeds from debt	0	20,000
Debt principal repayments	(2,105)	(21,902)
Cash dividends paid	(5,915)	(6,067)
Repurchases of common stock	(653)	(3,867)
Other financing activities, net	2,273	2
Net cash used in financing activities	(6,400)	(11,834)
Net decrease in cash, cash equivalents and restricted cash	(20,623)	(72,541)
Cash, cash equivalents and restricted cash, beginning of period	268,108	278,629
Total cash, cash equivalents and restricted cash, end of period	247,485	206,088
Supplementary Information
Right of use assets obtained in exchange for lease obligations	4,123	2,739
Cash paid for operating lease liabilities	5,035	4,270
Cash paid during the period for:
Interest	2,170	3,478
Income taxes	812	253
Non-cash investing and financing activities:
RSUs issued, net of forfeitures	4,726	7,459
Accrued cash dividends	$ 5,927	$ 6,086