Notes Receivable and Allowance for Losses Narrative (Details) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) category	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Notes Receivable and Allowance for Losses [Line Items]
Number of categories, credit losses for notes receivable | category			2
Notes receivable	$ 60,271		$ 60,271		$ 50,389
Allowance for losses on non-impaired loans	6,954		6,954		5,987
Amortization expense	2,995	$ 2,332	5,685	$ 4,610
Forgivable Notes Receivable [Member]
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	44,360		44,360		32,379
Allowance for losses on non-impaired loans	4,688		4,688		3,661
Amortization expense	2,100	1,200	3,900	2,400
Mezzanine & Other Notes Receivable [Member]
Notes Receivable and Allowance for Losses [Line Items]
Notes receivable	15,911		15,911		18,010
Allowance for losses on non-impaired loans	2,266		2,266		2,326
Mezzanine & Other Notes Receivable [Member] | Impaired Loans [Member]
Notes Receivable and Allowance for Losses [Line Items]
Impaired receivables, recorded investment	800		800		800
Impaired receivables, related allowance	800		800		800
Average notes receivable, nonaccrual status			800	12,200
Interest income, impaired loans	0	$ 22	33	$ 76
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		$ 1,500		$ 1,500