Condensed Consolidated Balance Sheets (Unaudited) (Parentheticals) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Cash and cash equivalents	$ 242,604	$ 262,273	$ 200,263
Receivables, net	477,718	547,417	380,985
Contract assets	226,518	211,441	213,023
Other current assets	60,001	46,016	62,755
Property and equipment, net	534,958	542,297	552,504
Accounts payable	312,105	400,775	216,150
Contract liabilities	133,811	95,737	104,260
Accrued expenses and other current liabilities	$ 355,393	$ 337,300	$ 308,086
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	3,000,000	3,000,000	3,000,000
Preferred stock, outstanding (in shares)	0	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000	150,000,000
Common stock, shares issued (in shares)	45,592,292	45,503,805	46,812,366
Common stock, shares outstanding (in shares)	45,592,292	45,503,805	46,812,366
Consolidated Construction Corporate Joint Venture [Member]
Cash and cash equivalents	$ 101,698	$ 78,132	$ 131,481
Receivables, net	28,320	29,564	24,990
Contract assets	17,584	25,034	9,354
Other current assets	16,078	13,350	11,795
Property and equipment, net	30,047	31,136	35,377
Accounts payable	58,475	57,795	37,853
Contract liabilities	47,509	20,994	46,804
Accrued expenses and other current liabilities	$ 2,458	$ 2,415	$ 3,577