CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
REVENUE	$ 1,332,978	$ 1,340,739	$ 3,726,477	$ 3,719,642
COST OF OPERATIONS	(1,208,310)	(1,240,538)	(3,386,947)	(3,430,062)
GROSS PROFIT	124,668	100,201	339,530	289,580
General and administrative expenses	(63,749)	(61,227)	(189,660)	(199,641)
INCOME FROM CONSTRUCTION OPERATIONS	60,919	38,974	149,870	89,939
Other income, net	2,048	6,195	5,214	6,098
Interest expense	(15,041)	(11,214)	(44,655)	(33,885)
INCOME BEFORE INCOME TAXES	47,926	33,955	110,429	62,152
Provision for income taxes	(19,125)	(14,278)	(44,868)	(25,572)
NET INCOME	$ 28,801	$ 19,677	$ 65,561	$ 36,580
BASIC EARNINGS PER COMMON SHARE (in dollars per share)	$ 0.59	$ 0.40	$ 1.33	$ 0.75
DILUTED EARNINGS PER COMMON SHARE (in dollars per share)	$ 0.57	$ 0.40	$ 1.32	$ 0.74
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
BASIC (in shares)	49,185	49,070	49,132	48,951
DILUTED (in shares)	50,100	49,775	49,649	49,718