Construction and Line Item Joint Ventures - Unconsolidated Construction Joint Ventures (Details) (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Dec. 31, 2010
Construction Joint Venture [Line Items]
Equity in construction joint ventures	$ 97,415,000		$ 80,496,000		$ 97,415,000		$ 80,496,000		$ 74,716,000
Cash and Cash Equivalents [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Assets	356,399,000		273,173,000		356,399,000		273,173,000		318,408,000
Other Assets, Current and Longterm [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Assets	265,549,000		192,606,000		265,549,000		192,606,000		212,911,000
Accounts Payable [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Liabilities	85,602,000		49,767,000		85,602,000		49,767,000		72,658,000
Billings in Excess of Costs and Estimated Earnings [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Liabilities	302,039,000		211,822,000		302,039,000		211,822,000		282,702,000
Accrued Liabilities [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Liabilities	9,460,000		13,837,000		9,460,000		13,837,000		8,893,000
Minimum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	227,600,000				227,600,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	45.00%				45.00%
Minimum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	57,600,000				57,600,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	20.00%				20.00%
Minimum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	52,900,000				52,900,000
Minimum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	21,100,000				21,100,000
Minimum [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Per Project Remaining to be Recognized on Line Item Construction Joint Ventures	900,000				900,000
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	2,400,000				2,400,000
Maximum [Member] | Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	312,100,000				312,100,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	60.00%				60.00%
Maximum [Member] | Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	975,400,000				975,400,000
Proportionate Share of the Consolidated Joint Ventures Equity Owned by or Beneficial Interest in the Reporting Entity Directly or Indirectly	49.00%				49.00%
Maximum [Member] | Joint Venture Unconsolidated [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	154,900,000				154,900,000
Revenue Per Project Remaining to be Recognized on Line Item Construction Joint Ventures	43,800,000				43,800,000
Maximum [Member] | Reporting Entitys Interest in Joint Venture [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Construction Contract Value	71,300,000				71,300,000
Maximum [Member] | Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	196,100,000				196,100,000
Partnership Interest [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	1,700,000,000				1,700,000,000
Joint Venture Consolidated [Member] | Consolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	2				2
Joint Venture Unconsolidated [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	9				9
Unconsolidated Construction Joint Venture Revenue	243,654,000		168,981,000		667,920,000		427,379,000
Unconsolidated Construction Joint Venture Cost of Revenue	212,485,000		157,932,000		546,495,000		386,316,000
Reporting Entitys Interest in Joint Venture [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Assets	243,425,000		178,163,000		243,425,000		178,163,000		206,834,000
Unconsolidated Construction Joint Venture Liabilities	146,010,000		97,667,000		146,010,000		97,667,000		132,118,000
Unconsolidated Construction Joint Venture Revenue	85,575,000		48,191,000		219,563,000		126,954,000
Unconsolidated Construction Joint Venture Cost of Revenue	71,979,000		46,354,000		175,630,000		124,808,000
Unconsolidated Construction Joint Venture Gross Profit Loss	13,596,000		1,837,000		43,933,000		2,146,000
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	600,000,000				600,000,000
Other Partners Interest in Partnerships [Member] | Unconsolidated Construction Joint Venture [Member]
Construction Joint Venture [Line Items]
Unconsolidated Construction Joint Venture Assets	378,523,000		287,616,000		378,523,000		287,616,000		324,485,000
Unconsolidated Construction Joint Venture Liabilities	251,091,000		177,759,000		251,091,000		177,759,000		232,135,000
Unconsolidated Construction Joint Venture Revenue	158,079,000	[1]	120,790,000	[1]	448,357,000	[1]	300,425,000	[1]
Unconsolidated Construction Joint Venture Cost of Revenue	140,506,000	[1]	111,578,000	[1]	370,865,000	[1]	261,508,000	[1]
Revenue Remaining to be Recognized on Unconsolidated Construction Joint Ventures	$ 1,100,000,000				$ 1,100,000,000
Line Item Joint Venture [Member]
Construction Joint Venture [Line Items]
Number of Active Joint Venture Projects	4				4

[1] The volume and stage of completion of contracts from our unconsolidated construction joint ventures may cause fluctuations in cash and cash equivalents as well as billings in excess of costs and estimated earnings between periods.