Revisions in Estimates (Details) (USD $)	3 Months Ended										12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Change in Accounting Estimate [Line Items]
Revenue Recognition, Percentage of Completion, Recognition Threshold											25.00%
Initial gross profit impact from projects exceeding threshold	$ 49,751,000	$ 55,858,000	[1]	$ 49,596,000	[2]	$ 30,058,000	$ 56,808,000	$ 101,099,000	$ 51,916,000	$ 24,936,000	$ 185,263,000	$ 234,759,000	$ 247,963,000
Financial Effect on Future Periods	0										0
Amount Considered Significant on Individual Project Gross Profit	1,000,000											1,000,000
Construction Contract Backlog, Percent	2.00%										2.00%
Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability											1,700,000	18,100,000	6,200,000
Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Total Contract Value	75,000,000										75,000,000
Large Project Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Total Contract Value	75,000,000										75,000,000
Contracts Accounted for under Percentage of Completion [Member] | Large Project Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability											25,500,000	64,600,000	8,900,000
Contracts Accounted for under Percentage of Completion [Member] | Large Project Construction [Member] | Noncontrolling Interest [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability											(5,600,000)	3,100,000	2,800,000
Upward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Initial gross profit impact from projects exceeding threshold											9,100,000	16,400,000	55,400,000
Increase (Decrease) on Project Profitability											16,100,000	8,100,000	13,600,000
Number of Projects with Estimate Changes											6	6	7
Upward Estimate Change [Member] | Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											1,100,000	1,000,000	1,000,000
Upward Estimate Change [Member] | Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											3,700,000	1,700,000	3,500,000
Upward Estimate Change [Member] | Large Project Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability											77,500,000	92,000,000	28,300,000
Number of Projects with Estimate Changes											7	10	9
Upward Estimate Change [Member] | Large Project Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											2,600,000	1,000,000	1,100,000
Upward Estimate Change [Member] | Large Project Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											34,000,000	24,500,000	6,900,000
Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability											(17,800,000)	(26,200,000)	(7,400,000)
Number of Projects with Estimate Changes											5	9	4
Downward Estimate Change [Member] | Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											(1,000,000)	(1,000,000)	(1,400,000)
Downward Estimate Change [Member] | Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											(6,900,000)	(6,600,000)	(2,600,000)
Downward Estimate Change [Member] | Large Project Construction [Member]
Change in Accounting Estimate [Line Items]
Increase (Decrease) on Project Profitability											(52,000,000)	(27,400,000)	(19,400,000)
Number of Projects with Estimate Changes											5	1	5
Downward Estimate Change [Member] | Large Project Construction [Member] | Minimum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											(1,900,000)	(27,400,000)	(1,200,000)
Downward Estimate Change [Member] | Large Project Construction [Member] | Maximum [Member]
Change in Accounting Estimate [Line Items]
Range Of Effect On Gross Profit											$ (23,500,000)	$ (27,400,000)	$ (5,100,000)
Not, Complete or Substantially Complete [Member] | Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Number of Projects with Estimate Changes											2
Complete or Substantially Complete [Member] | Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Number of Projects with Estimate Changes											3
Contract 1, that was not complete or substantially complete [Member] | Not, Complete or Substantially Complete [Member] | Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Percent Complete	85.20%										85.20%
Contract 2, that was not complete or substantially complete [Member] | Not, Complete or Substantially Complete [Member] | Downward Estimate Change [Member] | Construction [Member]
Change in Accounting Estimate [Line Items]
Percent Complete	86.20%										86.20%

[1] Net income for the quarter ended September 30 is approximately $2.1 million ($3.0 million pre-tax) higher than the amount previously reported in our Quarterly Report Form 10-Q for the quarterly period ended September 30, 2013 of $4.5 million. The pre-tax adjustments were primarily related to (i) an over-accrual of pre-bid costs which affected selling, general and administrative expenses and accrued and other current liabilities in the amount of $1.4 million and (ii) a revision in equipment-related costs, which affected cost of revenue and property and equipment in the amount of $1.6 million.

[2] Net income for the quarter ended June 30 is approximately $1.4 million ($1.9 million pre-tax) lower than the amounts previously reported in our Form 10-Q for the quarter period ended June 30, 2013 of $3.2 million. The pre-tax adjustments were primarily related to equipment-related costs of $1.7 million.