Notes Receivable and Allowance for Losses Narrative (Details) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Dec. 31, 2012	Dec. 02, 2011
Notes Receivable, Related Parties	$ 61,634,000		$ 60,068,000
Allowance for losses on non-impaired loans	11,286,000		10,550,000
Amortization expense	2,175,000	2,017,000
Receivables, allowance for doubtful accounts	11,298,000		10,820,000
Mortgage Loans Acquired				11,500,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Commercial, Contractually Required Payments Receivable at Acquisition				12,000,000
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition				9,700,000
Mortgage loans receivable, allowance for uncollectable amounts	0		0
Certain Loans Acquired Accretable Yield				7.36%
Senior Notes [Member]
Notes Receivable, Related Parties	27,842,000		27,549,000
Notes Receivable [Member]
Financing Receivable, Recorded Investment, Past Due	9,838,000		10,295,000
Financing Receivable, Recorded Investment, Current	34,846,000		33,538,000
Notes Receivable [Member] | Senior Notes [Member]
Financing Receivable, Recorded Investment, Past Due	0		0
Financing Receivable, Recorded Investment, Current	27,842,000		27,549,000
Forgivable Notes Receivable [Member]
Notes Receivable, Related Parties	16,950,000		16,235,000
Allowance for losses on non-impaired loans	1,695,000		1,623,000
Amortization expense	900,000	600,000
Financing Receivable, Recorded Investment, Past Due	0		0
Forgivable Notes Receivable [Member] | Senior Notes [Member]
Notes Receivable, Related Parties	0		0
Mezzanine & Other Notes Receivable [Member]
Notes Receivable, Related Parties	44,684,000		43,833,000
Allowance for losses on non-impaired loans	9,591,000		8,927,000
Impaired Financing Receivable, Recorded Investment	13,300,000		13,300,000
Impaired Financing Receivable, Related Allowance	8,300,000		8,300,000
Face value of notes value deemed impaired	5,000,000		5,000,000
Receivables, allowance for doubtful accounts	0		0
Impaired Financing Receivable, Interest Income, Cash Basis Method	66,000	31,000
Mezzanine & Other Notes Receivable [Member] | Senior Notes [Member]
Notes Receivable, Related Parties	27,842,000		27,549,000
Mezzanine & Other Notes Receivable [Member] | Non-impaired Loans [Member]
Allowance for losses on non-impaired loans	1,300,000		600,000
Mezzanine & Other Notes Receivable [Member] | Notes Receivable [Member] | Senior Notes [Member]
Financing Receivable, Recorded Investment, Current	$ 7,900,000		$ 7,900,000