Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Operating activities
Net loss	$ (73,511)	$ (81,407)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	57,269	61,747
Amortization related to the 2.75% Convertible Notes (See Note 14)	4,255	0
Gain on sales of property and equipment, net	(1,813)	(6,835)
Stock-based compensation	3,936	7,221
Equity in net loss from unconsolidated joint ventures	30,506	72,835
Net income from affiliates	(2,062)	(3,884)
Non-cash impairment charges (See Note 4)	24,413	0
Other non-cash adjustments	1,832	4,627
Changes in assets and liabilities:
Receivables	(35,486)	(79,090)
Contract assets, net	83,065	(20,426)
Inventories	(16,138)	(12,329)
Contributions to unconsolidated construction joint ventures and affiliates	(24,223)	(45,500)
Distributions from unconsolidated construction joint ventures and affiliates	7,146	830
Other assets, net	(14,603)	(32,785)
Accounts payable	(44,103)	42,477
Accrued expenses and other current liabilities, net	12,000	(996)
Net cash provided by (used in) operating activities	12,483	(93,515)
Investing activities
Purchases of marketable securities	(4,996)	0
Proceeds from called marketable securities	20,000	0
Maturities of marketable securities	10,000	5,000
Purchases of property and equipment	(52,236)	(54,354)
Proceeds from sales of property and equipment	7,278	7,870
Cash paid to purchase businesses, net of cash and restricted cash acquired	0	(6,227)
Other investing activities, net	(1,453)	(215)
Net cash used in investing activities	(21,407)	(47,926)
Financing activities
Proceeds from debt	50,000	75,499
Debt principal repayments	(4,212)	(43,842)
Cash dividends paid	(11,842)	(12,152)
Repurchases of common stock	(728)	(3,948)
Contributions from non-controlling partners	5,500	0
Distributions to non-controlling partners	(7,860)	(3,200)
Other financing activities, net	392	1,238
Net cash provided by financing activities	31,250	13,595
Net increase (decrease) in cash, cash equivalents and restricted cash	22,326	(127,846)
Cash, cash equivalents and restricted cash, beginning of period	268,108	278,629
Total cash, cash equivalents and restricted cash, end of period	290,434	150,783
Supplementary Information
Right of use assets obtained in exchange for lease obligations	8,804	9,835
Cash paid for operating lease liabilities	10,601	8,811
Cash paid during the period for:
Interest	8,874	8,381
Income taxes	937	11,463
Non-cash investing and financing activities:
RSUs issued, net of forfeitures	4,834	8,541
Accrued cash dividends	$ 5,935	$ 6,089