Business Segments (Details 2) (USD $) In Thousands, unless otherwise specified	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
Principal Geographical Areas Information
Revenues	$ 1,099,291	$ 1,030,388	$ 1,053,065	$ 992,928	$ 1,114,198	$ 1,099,393	$ 985,346	$ 912,534	$ 4,175,672	$ 4,111,471	$ 3,716,317
Income (loss) from construction operations	70,175	58,094	39,474	36,079	60,724	54,676	(354,174)	16,963	203,822	(221,811)	168,376
Assets	3,397,438				3,296,410				3,397,438	3,296,410	3,613,127
Corporate
Principal Geographical Areas Information
Income (loss) from construction operations									(47,432)	(45,094)	(44,336)
Assets	576,127				727,699				576,127	727,699	604,455
United States | Reportable Geographical Components
Principal Geographical Areas Information
Revenues									4,000,380	3,925,733	3,508,349
Income (loss) from construction operations									238,989	(195,457)	184,268
Assets	3,182,706				3,107,808				3,182,706	3,107,808	3,460,470
Foreign and U.S. Territories | Reportable Geographical Components
Principal Geographical Areas Information
Revenues									175,292	185,738	207,968
Income (loss) from construction operations									12,265	18,740	28,444
Assets	$ 214,732				$ 188,602				$ 214,732	$ 188,602	$ 152,657