CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating activities
Net loss	$ (125,042)	$ (15,743)
Adjustments to reconcile net loss to net cash used in operating activities:
Depreciation, depletion and amortization	61,747	43,547
Gain on sales of property and equipment, net	(6,835)	(2,048)
Change in deferred income taxes	(35,192)	0
Stock-based compensation	7,221	10,193
Equity in net loss from unconsolidated joint ventures	105,834	13,418
Net income from affiliates	(3,884)	(3,758)
Other non-cash adjustments	4,630	0
Changes in assets and liabilities, net of the effects of acquisitions:
Receivables	(78,081)	(24,821)
Contract assets, net	(23,775)	(76,166)
Inventories	(12,905)	(9,526)
Contributions to unconsolidated construction joint ventures	(45,500)	(55,733)
Distributions from unconsolidated construction joint ventures	830	11,201
Other assets, net	(15,361)	4,192
Accounts payable	48,230	24,559
Accrued expenses and other current liabilities, net	24,568	5,240
Net cash used in operating activities	(93,515)	(75,445)
Investing activities
Purchases of marketable securities	0	(9,952)
Maturities of marketable securities	5,000	60,000
Purchases of property and equipment ($3,914 and $11,369 related to CCJVs)	(54,354)	(36,471)
Proceeds from sales of property and equipment	7,870	2,704
Cash paid to purchase businesses, net of cash and restricted cash acquired	(6,227)	(55,030)
Other investing activities, net	(215)	269
Net cash used in investing activities	(47,926)	(38,480)
Financing activities
Proceeds from debt	75,499	105,250
Debt principal repayments	(43,842)	(1,250)
Cash dividends paid	(12,152)	(10,389)
Repurchases of common stock	(3,948)	(6,165)
Distributions to non-controlling partners	(3,200)	(6,400)
Other financing activities, net	1,238	429
Net cash provided by financing activities	13,595	81,475
Net decrease in cash, cash equivalents and restricted cash	(127,846)	(32,450)
Cash and cash equivalents and restricted cash of $5,825 and $0 at beginning of each period	278,629	233,711
Cash, cash equivalents and restricted cash of $5,825 and $5,746 at end of each period	150,783	201,261
Supplementary Information
Right of use assets obtained in exchange for lease obligations	7,096	0
Cash paid for operating lease liabilities	4,582	0
Cash paid during the period for:
Interest	8,381	6,134
Income taxes	11,463	7,246
Non-cash investing and financing activities:
Common stock issued in acquisition	0	321,075
Premium on 8.0% Convertible Notes	0	30,702
RSUs issued, net of forfeitures	8,541	13,022
Accrued cash dividends	$ 6,089	$ 5,940