Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating activities
Net loss	$ (65,323)	$ (72,538)
Adjustments to reconcile net loss to net cash provided by (used in) operating activities:
Depreciation, depletion and amortization	24,581	28,447
Amortization related to the 2.75% Convertible Notes	2,314	2,463
Gain on sales of property and equipment, net	(2,554)	(623)
Stock-based compensation	1,065	2,398
Equity in net (income) loss from unconsolidated joint ventures	(418)	11,816
Non-cash impairment charges (see Note 3)	0	24,413
Changes in assets and liabilities:
Accrual for legal settlement (see Note 16)	129,000	0
Insurance receivable for legal settlement (see Note 16)	(63,000)	0
Receivables	123,274	71,040
Contract assets, net	(33,528)	22,997
Inventories	(4,249)	(9,880)
Contributions to unconsolidated construction joint ventures	(22,180)	(13,767)
Distributions from unconsolidated construction joint ventures and affiliates	1,684	2,939
Other assets, net	(22,926)	(12,184)
Accounts payable	(49,399)	(87,979)
Accrued expenses and other current liabilities, net	19,746	10,333
Net cash provided by (used in) operating activities	38,087	(20,125)
Investing activities
(Purchases) maturities of marketable securities	(5,000)	5,000
Proceeds from called marketable securities	0	20,000
Purchases of property and equipment	(18,777)	(21,435)
Proceeds from sales of property and equipment	3,004	3,865
Other investing activities, net	4,470	(1,528)
Net cash (used in) provided by investing activities	(16,303)	5,902
Financing activities
Debt principal repayments	(2,150)	(2,105)
Cash dividends paid	(5,937)	(5,915)
Repurchases of common stock	(2,299)	(653)
Contributions from non-controlling partners	8,361	3,750
Distributions to non-controlling partners	(2,902)	(1,470)
Other financing activities, net	(65)	(7)
Net cash used in financing activities	(4,992)	(6,400)
Net increase (decrease) in cash, cash equivalents and restricted cash	16,792	(20,623)
Cash, cash equivalents and $1,512 and $5,835 in restricted cash at beginning of period	437,648	268,108
Cash, cash equivalents and $1,512 and $4,881 in restricted cash at end of period	454,440	247,485
Supplementary Information
Right of use assets obtained in exchange for lease obligations	603	4,123
Cash paid for operating lease liabilities	5,457	5,035
Cash paid during the period for:
Interest	2,544	2,170
Income taxes	148	812
Non-cash investing and financing activities:
RSUs issued, net of forfeitures	(133)	4,726
Dividends declared but not paid	5,953	5,927
Contributions from non-controlling partners	5,379	0
Accrued equipment purchases	$ 2,443	$ 692