CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
REVENUE	$ 1,308,130	$ 1,312,438	$ 2,393,499	$ 2,378,903
COST OF OPERATIONS	(1,198,360)	(1,213,818)	(2,178,637)	(2,189,524)
GROSS PROFIT	109,770	98,620	214,862	189,379
General and administrative expenses	(60,941)	(67,739)	(125,911)	(138,414)
INCOME FROM CONSTRUCTION OPERATIONS	48,829	30,881	88,951	50,965
Other income (expense), net	2,485	379	3,166	(97)
Interest expense	(15,534)	(11,268)	(29,614)	(22,671)
INCOME BEFORE INCOME TAXES	35,780	19,992	62,503	28,197
Provision for income taxes	(14,419)	(8,215)	(25,743)	(11,294)
NET INCOME	$ 21,361	$ 11,777	$ 36,760	$ 16,903
BASIC EARNINGS PER COMMON SHARE (in dollars per share)	$ 0.43	$ 0.24	$ 0.75	$ 0.35
DILUTED EARNINGS PER COMMON SHARE (in dollars per share)	$ 0.43	$ 0.24	$ 0.74	$ 0.34
WEIGHTED AVERAGE COMMON SHARES OUTSTANDING:
BASIC (in shares)	49,131	49,028	49,105	48,890
DILUTED (in shares)	49,561	49,828	49,423	49,688