Notes Receivable and Allowance for Losses Narrative (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($) category	Sep. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Notes Receivable and Allowance for Losses [Line Items]
Number of categories, credit losses for notes receivable | category			2
Notes receivable	$ 83,045,000		$ 83,045,000		$ 50,389,000
Allowance for losses on non-impaired loans	6,808,000		6,808,000		5,987,000
Amortization expense	3,108,000	$ 2,293,000	8,793,000	$ 6,903,000
Forgivable Notes Receivable [Member]
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	43,435,000		43,435,000		32,379,000
Allowance for losses on non-impaired loans	4,571,000		4,571,000		3,661,000
Amortization expense	2,100,000	1,200,000	6,000,000	3,600,000
Mezzanine & Other Notes Receivable [Member]
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	39,610,000		39,610,000		18,010,000
Allowance for losses on non-impaired loans	2,237,000		2,237,000		2,326,000
Mezzanine & Other Notes Receivable [Member] | Impaired Loans [Member]
Notes Receivable and Allowance for Losses [Line Items]
Impaired receivables, recorded investment	800,000		800,000		800,000
Impaired receivables, related allowance	800,000		800,000		800,000
Average notes receivable, nonaccrual status			800,000	12,200,000
Interest income, impaired loans	0	$ 11,000	33,000	$ 87,000
Mezzanine & Other Notes Receivable [Member] | Non-impaired Loans [Member]
Notes Receivable and Allowance for Losses [Line Items]
Allowance for losses on non-impaired loans	$ 1,500,000		$ 1,500,000		$ 1,500,000