Notes Receivable and Allowance for Losses Narrative (Details) (USD $)	3 Months Ended		9 Months Ended					3 Months Ended		9 Months Ended					1 Months Ended						3 Months Ended		9 Months Ended							1 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 Senior Notes [Member]	Dec. 31, 2012 Senior Notes [Member]	Sep. 30, 2013 Forgivable Notes Receivable [Member]	Sep. 30, 2012 Forgivable Notes Receivable [Member]	Sep. 30, 2013 Forgivable Notes Receivable [Member]	Sep. 30, 2012 Forgivable Notes Receivable [Member]	Dec. 31, 2012 Forgivable Notes Receivable [Member]	Sep. 30, 2013 Forgivable Notes Receivable [Member] Senior Notes [Member]	Dec. 31, 2012 Forgivable Notes Receivable [Member] Senior Notes [Member]	Dec. 31, 2011 Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2013 Mezzanine & Other Notes Receivable [Member]	Dec. 31, 2012 Mezzanine & Other Notes Receivable [Member]	Dec. 02, 2011 Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2013 Mezzanine & Other Notes Receivable [Member] Senior Notes [Member]	Dec. 31, 2012 Mezzanine & Other Notes Receivable [Member] Senior Notes [Member]	Sep. 30, 2013 Impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2012 Impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2013 Impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2012 Impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Dec. 31, 2012 Impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2013 Non-impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Dec. 31, 2012 Non-impaired Loans [Member] Mezzanine & Other Notes Receivable [Member]	Sep. 30, 2013 Minimum [Member]	Sep. 30, 2013 Maximum [Member]	Nov. 12, 2013 Subsequent Event [Member] Mezzanine & Other Notes Receivable [Member] Senior Notes [Member]
Financing Receivable, Recorded Investment, Past Due								$ 0		$ 0		$ 0				$ 19,815,000	$ 10,295,000		$ 9,500,000	$ 0
Notes Receivable, Related Parties	63,219,000		63,219,000		60,068,000	27,548,000	27,549,000	19,018,000		19,018,000		16,235,000	0	0		44,201,000	43,833,000		27,548,000	27,549,000
Allowance for losses on non-impaired loans	11,798,000		11,798,000		10,550,000			1,902,000		1,902,000		1,623,000				9,896,000	8,927,000									1,400,000	600,000
Amortization expense	2,379,000	1,995,000	7,074,000	5,989,000				1,100,000	700,000	3,000,000	2,000,000
Impaired Financing Receivable, Recorded Investment																					13,200,000		13,200,000		13,300,000
Impaired Financing Receivable, Related Allowance																					8,500,000		8,500,000		8,300,000
Face value of notes value deemed impaired																					4,700,000		4,700,000		5,000,000
Impaired Financing Receivable, Interest Income, Cash Basis Method																					81,000	38,000	200,000	100,000
Mortgage Loans Acquired																		11,500,000
Payments to Acquire Mortgage Notes Receivable															7,900,000
Required payments on acquired mortgage																		12,000,000
Expected payments on acquired mortgage																		9,700,000
Financing Receivable, Acquired with Deteriorated Credit Quality																			7,900,000	7,900,000
Accretable yield at acquisition																		1,800,000
Accretable yield percentage at acquisition																		7.36%
Collections of mezzanine and other notes receivable			224,000	110,000																										9,500,000
Mortgage loans receivable, allowance for uncollectable amounts																			$ 0	$ 0
Number of Days Past Due																												30	89