CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
CONSOLIDATED STATEMENTS OF OPERATIONS [Abstract]
REVENUE	$ 1,246,599	$ 1,332,978	$ 1,308,130	$ 1,085,369	$ 1,200,830	$ 1,340,739	$ 1,312,438	$ 1,066,465	$ 4,973,076	$ 4,920,472	$ 4,492,309
COST OF OPERATIONS									(4,515,886)	(4,564,219)	(3,986,867)
GROSS PROFIT	117,660	124,668	109,770	105,092	66,673	100,201	98,620	90,759	457,190	356,253	505,442
General and administrative expenses									(255,270)	(250,840)	(263,752)
INCOME FROM CONSTRUCTION OPERATIONS	52,050	60,919	48,829	40,122	15,474	38,974	30,881	20,084	201,920	105,413	241,690
Other income (expense), net									6,977	13,569	(8,217)
Interest expense									(59,782)	(45,143)	(46,035)
INCOME BEFORE INCOME TAXES	38,685	47,926	35,780	26,724	11,687	33,955	19,992	8,205	149,115	73,839	187,438
Provision for income taxes									(53,293)	(28,547)	(79,502)
NET INCOME	$ 30,260	$ 28,801	$ 21,361	$ 15,400	$ 8,712	$ 19,677	$ 11,777	$ 5,126	$ 95,822	$ 45,292	$ 107,936
BASIC EARNINGS PER COMMON SHARE	$ 0.62	$ 0.59	$ 0.43	$ 0.31	$ 0.18	$ 0.40	$ 0.24	$ 0.11	$ 1.95	$ 0.92	$ 2.22
DILUTED EARNINGS PER COMMON SHARE	$ 0.60	$ 0.57	$ 0.43	$ 0.31	$ 0.18	$ 0.40	$ 0.24	$ 0.10	$ 1.92	$ 0.91	$ 2.20
WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING:
BASIC									49,150	48,981	48,562
DILUTED									49,864	49,666	49,114