Other Investments (LNR Property Narrative) (Details) (LNR Property LLC (LNR), USD $)	1 Months Ended			3 Months Ended		6 Months Ended	12 Months Ended
	Apr. 19, 2013		Jul. 31, 2010	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2013	Dec. 31, 2013	Sep. 30, 2013		Sep. 30, 2012		Sep. 30, 2011		Jul. 28, 2010
LNR Property LLC (LNR)
Schedule of Equity Method Investments [Line Items]
iStar's ownership percentage	24.00%	[1]						0.00%	[1]	24.00%	[1]	24.00%	[1]	24.00%
Percentage of ownership acquired by the Company and a group of investors														100.00%
Contribution towards principal amount of Holdco Notes			$ 100,000,000
Amount of cash contributed in exchange for equity interest			100,000,000
Equity interest in investee														120,000,000
Sales proceeds pursuant to contract	220,300,000			220,281,000	0	0	220,281,000
Real estate, net proceeds held in escrow for potential indemnification obligations						$ 25,200,000	$ 25,200,000

[1] The Company recorded its investment in LNR, which was sold in April 2013, on a one quarter lag, therefore, amounts in the Company's financial statements for the year ended December 31, 2013 are based on balances and results from LNR for the period from October 1, 2012 to April 19, 2013. The amounts in the Company's financial statements for the year ended December 31, 2012 and 2011 are based on balances and results from LNR for the years ended September 30, 2012 and 2011, respectively.