Changes in Completed Operations (Detail) (USD $) In Thousands, unless otherwise specified				3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Jun. 30, 2012 Insured Operations	Jun. 30, 2011 Insured Operations	Jun. 30, 2012 Insured Operations	Jun. 30, 2011 Insured Operations	Jun. 30, 2012 Self Insured Operations	Jun. 30, 2011 Self Insured Operations	Jun. 30, 2012 Self Insured Operations	Jun. 30, 2011 Self Insured Operations
Completed Operations [Line Items]
Total completed operations	$ 117,129	$ 109,390	$ 115,103	$ 117,129	$ 115,103	$ 117,129	$ 115,103	$ 0	$ 0	$ 0	$ 0
Balance, beginning of the period	117,129	109,390	115,103	103,980	116,939	109,390	102,860	0	0	0	15,613
Reserves provided				17,517	2,518	18,908	1,174	0	0	0	907
Insurance purchased				0	0	0	16,520	0	0	0	(16,520)
Claims paid				(4,368)	(4,354)	(11,169)	(5,451)
Balance, end of the period	$ 117,129	$ 109,390	$ 115,103	$ 117,129	$ 115,103	$ 117,129	$ 115,103	$ 0	$ 0	$ 0	$ 0