Capitalized Data and Database Development Costs, Net (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Research And Development [Line Items]
Capitalized data and database costs gross	$ 486,069,000	$ 444,516,000
Less accumulated amortization	(163,780,000)	(140,510,000)
Capitalized data and database costs, net	322,289,000	304,006,000
Amortization	27,300,000	23,200,000	17,700,000
Property Data [Member]
Research And Development [Line Items]
Capitalized data and database costs gross	417,565,000	373,333,000
Flood [Member]
Research And Development [Line Items]
Capitalized data and database costs gross	52,916,000	52,916,000
Eviction Data [Member]
Research And Development [Line Items]
Capitalized data and database costs gross	$ 15,588,000	$ 18,267,000