Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Cash and cash equivalents	$ 436,136	$ 262,273
Receivables, net	540,812	547,417
Contract assets	164,939	211,441
Other current assets	42,199	46,016
Property and equipment, net	527,016	542,297
Accounts payable	359,160	400,775
Contract liabilities	171,321	95,737
Accrued expenses and other current liabilities	$ 404,497	$ 337,300
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	3,000,000	3,000,000
Preferred stock, outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	150,000,000	150,000,000
Common stock, shares issued (in shares)	45,668,541	45,503,805
Common stock, shares outstanding (in shares)	45,668,541	45,503,805
Consolidated Construction Corporate Joint Venture [Member]
Cash and cash equivalents	$ 74,819	$ 78,132
Receivables, net	56,147	29,564
Contract assets	33,838	25,034
Other current assets	13,252	13,350
Property and equipment, net	23,704	31,136
Accounts payable	53,033	57,795
Contract liabilities	79,777	20,994
Accrued expenses and other current liabilities	$ 4,410	$ 2,415