Net Investments in Properties and Real Estate Under Construction (Details 1) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Investments in real estate:
Accumulated depreciation (inclusive of amounts attributable to consolidated VIEs of $3,801 and $1,617, respectively)	$ (85,002)	$ (43,267)
Net investments in properties	2,275,575	1,635,025
Real Estate
Investments in real estate:
Land	491,584	390,445
Building	1,614,188	1,109,706
Accumulated depreciation (inclusive of amounts attributable to consolidated VIEs of $3,801 and $1,617, respectively)	(77,245)	(40,522)
Net investments in properties	2,028,527	1,459,629
Operating Real Estate [Member]
Investments in real estate:
Land	60,493	43,950
Building	193,067	132,478
Furniture, fixtures and equipment	1,245	1,713
Accumulated depreciation (inclusive of amounts attributable to consolidated VIEs of $3,801 and $1,617, respectively)	(7,757)	(2,745)
Net investments in properties	$ 247,048	$ 175,396