Related Party Transactions (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended						12 Months Ended	3 Months Ended								3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 SIGI	Mar. 31, 2012 SIGI	Mar. 31, 2013 Pluris, LLC	Mar. 31, 2012 Pluris, LLC	Dec. 31, 2010 Pluris, LLC	Mar. 31, 2013 Roger Newnham	Mar. 31, 2012 Roger Newnham	Mar. 31, 2013 Lemmie Rockford	Mar. 31, 2012 Lemmie Rockford	Mar. 31, 2013 Quality RE Partners item	Mar. 31, 2013 Westpac and St. - Bernard Levee Partners joint venture	Mar. 31, 2012 Westpac and St. - Bernard Levee Partners joint venture	Nov. 17, 2012 Alvah, Inc.	Mar. 31, 2013 Alvah, Inc. ARB	Mar. 31, 2013 Alvah, Inc. Q3C
Related party transactions
Lease payments to related party	$ 399	$ 325	$ 235	$ 231		$ 291		$ 75	$ 72	$ 23	$ 23	$ 66
Amount of agreement to construct a wastewater facility							6,100
Related party revenues recognized					0								20	0
Number of former shareholders owning leased property												3
Number of current employees owning leased property												2
Membership interest (as a percent)															49.00%
Subcontractor payments made to related party																$ 1,245	$ 212