Notes Receivable and Allowance for Losses - Narrative (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014 category	Dec. 31, 2013	Dec. 31, 2012	Dec. 30, 2014	Dec. 02, 2011
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of notes receivable categories for evaluating credit losses	2
Number of days outstanding to consider loans outstanding past due in order to cease accruing interest (more than)	30 days
Allowance for losses on non-impaired loans	$ 5,201,000	$ 3,257,000
Notes receivable, related parties	50,389,000	56,234,000
Amortization expense	9,365,000	9,056,000	7,691,000
Collateral of Single-purpose Limited Liability Company [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Face value of notes value deemed impaired				9,600,000
Loan reserves on impaired loans				7,400,000
Impaired loans, carrying value				2,200,000
Business combination, assets acquired				13,500,000
Business combination, liabilities assumed				(10,700,000)
Business combination, net fair value				2,800,000
Recovery of bad debts				600,000
Senior [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable, related parties	10,152,000	18,052,000
Mezzanine & Other Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Face value of notes value deemed impaired	800,000	12,500,000
Loan reserves on impaired loans	800,000	8,300,000
Impaired loans, carrying value	0	4,200,000
Average mezzanine and other notes receivable on non-accrual status	11,500,000	12,900,000
Interest income on impaired loans, cash basis method	200,000	400,000
Allowance for losses on non-impaired loans	1,540,000	1,607,000
Mortgage loans acquired					11,500,000
Payments to acquire mortgage notes receivable					7,900,000
Contractually required payments receivable at acquisition					12,000,000
Cash flows expected to be collected at acquisition					9,700,000
Accretable yield, amount	1,800,000	1,800,000
Accretable yield, percentage	7.36%	7.36%
Notes receivable, related parties	18,010,000	35,609,000
Mezzanine & Other Notes Receivable [Member] | Senior [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage notes receivable, carrying amount		7,900,000
Mortgage loans receivable, allowance for uncollectable amounts		0
Notes receivable, related parties	10,152,000	18,052,000
Forgivable Notes Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for losses on non-impaired loans	3,661,000	1,650,000
Notes receivable, related parties	32,379,000	20,625,000
Forgivable, unsecured notes, past due	1,200,000
Amortization expense	5,000,000	4,200,000	2,800,000
Forgivable Notes Receivable [Member] | Senior [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable, related parties	$ 0	$ 0