Business Segment Information (Details) - USD ($) $ 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	Dec. 31, 2013
Segment Reporting Information [Line Items]
Revenue from external customers	$ 666,681	$ 803,905	$ 604,579	$ 439,452	$ 630,162	$ 751,376	$ 569,242	$ 420,249	$ 2,514,617	$ 2,371,029	$ 2,275,270
Gross profit	81,250	107,674	73,201	39,245	100,624	96,083	64,200	38,929	301,370	299,836	239,741
Segment assets	1,733,453				1,626,878				1,733,453	1,626,878	1,600,048
Reconciliation from Segment Totals to Consolidated [Abstract]
Cash and cash equivalents	189,326				252,836				189,326	252,836	255,961	$ 229,121
Receivables, net	419,345				340,822				419,345	340,822
Other current assets	39,908				26,985				39,908	26,985
Property and equipment, net	406,650				385,129				406,650	385,129
Investments in affiliates	35,668				33,182				35,668	33,182	32,361
Other noncurrent assets	85,449				84,789				85,449	84,789
Gross profit	81,250	107,674	$ 73,201	$ 39,245	100,624	$ 96,083	$ 64,200	$ 38,929	301,370	299,836	239,741
Selling, general and administrative expenses									219,299	203,817	193,256
Restructuring and impairment gains	(1,000)	$ 925							(1,925)	(6,003)	(2,643)
Gain on sales of property and equipment									(8,358)	(8,286)	(15,972)
Total Other Income (Expense)									(4,008)	6,881	9,503
Income before provision for income taxes									96,362	103,427	55,597
Construction [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									1,365,198	1,262,675	1,186,445
Large Project Construction [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									888,193	812,720	825,044
Construction Materials [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									261,226	295,634	263,781
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues									2,678,420	2,507,679	2,396,881
Gross profit									301,370	299,836	239,741
Depreciation, depletion and amortization									53,049	52,849	57,314
Segment assets	748,770				703,274				748,770	703,274	704,711
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit									301,370	299,836	239,741
Operating Segments [Member] | Construction [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									1,365,198	1,262,675	1,186,445
Gross profit									209,215	187,506	113,953
Depreciation, depletion and amortization									22,816	20,117	19,141
Segment assets	151,475				139,399				151,475	139,399	149,018
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit									209,215	187,506	113,953
Operating Segments [Member] | Large Project Construction [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									888,193	812,720	825,044
Gross profit									64,137	79,467	107,097
Depreciation, depletion and amortization									6,796	10,343	16,197
Segment assets	314,823				274,975				314,823	274,975	248,464
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit									64,137	79,467	107,097
Operating Segments [Member] | Construction Materials [Member]
Segment Reporting Information [Line Items]
Revenues									425,029	432,284	385,392
Gross profit									28,018	32,863	18,691
Depreciation, depletion and amortization									23,437	22,389	21,976
Segment assets	282,472				288,900				282,472	288,900	307,229
Reconciliation from Segment Totals to Consolidated [Abstract]
Gross profit									28,018	32,863	18,691
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									(163,803)	(136,650)	(121,611)
Intersegment Eliminations [Member] | Construction [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									0	0	0
Intersegment Eliminations [Member] | Large Project Construction [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									0	0	0
Intersegment Eliminations [Member] | Construction Materials [Member]
Segment Reporting Information [Line Items]
Revenue from external customers									(163,803)	(136,650)	(121,611)
Segment Reconciling Items [Member]
Reconciliation from Segment Totals to Consolidated [Abstract]
Cash and cash equivalents	189,326				252,836				189,326	252,836	255,961
Short-term and long-term marketable securities	127,779				105,695				127,779	105,695	102,067
Receivables, net	419,345				340,822				419,345	340,822	310,934
Deferred income taxes	0				4,329				0	4,329	32,785
Other current assets	113,010				85,556				113,010	85,556	60,615
Property and equipment, net	32,397				36,721				32,397	36,721	45,188
Other noncurrent assets	$ 67,158				$ 64,463				$ 67,158	$ 64,463	$ 55,426