Real Estate (Dispositions) (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) property	Jun. 30, 2014 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income from sales of real estate	$ 18,355	$ 17,180	$ 39,511	$ 33,674
Land development revenue	6,543	4,487	14,801	8,630
Land development cost of sales	$ 5,252	$ 3,611	$ 12,142	7,265
Noncontrolling Interest, Ownership Percentage by Parent	90.00%		90.00%
Property sold, aggregate, carrying value				6,700
Net Lease Asset Two
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of property held-for-sale			$ 25,600
Income from sales of real estate			$ 8,600
Net Lease
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sales of real estate				7,800
Impairment of long-lived assets to be disposed of or sold				3,000
Net Lease Asset One
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Initial term of ground lease			99 years
Lease incentive asset	$ 38,100		$ 38,100
Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Unpaid Purchase Price	16,100		16,100
Deferred Revenue	5,300		5,300
Condominium Units
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from sale of other real estate			91,300	94,800
Income from sales of real estate			30,900	33,700
Operating Properties
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sales of real estate			93,500
Deferred gain on sale of property	$ 5,300		$ 5,300
Net Lease Venture | Net Lease
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sales of real estate				$ 93,700
iStar's ownership percentage		51.90%		51.90%
Net Lease Venture | Net Lease Asset One
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sales of real estate				$ 93,700
Real Estate Equity Investment One [Member] | Land
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Property Contributed, Aggregate, Carrying Value				$ 9,500
Master Planned Community [Member] | Residential Real Estate
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of real estate properties sold | property			3	2