Single-family properties - Schedule of Single-Family Properties (Detail) (USD $)	Sep. 30, 2013 Property	Dec. 31, 2012 Property
Property Subject to or Available for Operating Lease [Line Items]
Number of properties	21,267	3,644
Net book value	$ 3,530,122,000	$ 505,713,000
Single-Family Properties Being Renovated [Member]
Property Subject to or Available for Operating Lease [Line Items]
Number of properties	4,147	1,857
Net book value	615,568,000	261,136,000
Leased Single-Family Properties [Member]
Property Subject to or Available for Operating Lease [Line Items]
Number of properties	14,384	1,164
Net book value	2,426,434,000	158,068,000
Vacant Single-Family Properties Available for Lease [Member]
Property Subject to or Available for Operating Lease [Line Items]
Number of properties	2,736	623
Net book value	$ 488,120,000	$ 86,509,000