Notes Receivable and Allowance for Losses - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended	12 Months Ended
	Sep. 12, 2017	Mar. 31, 2018	Dec. 31, 2018	Dec. 31, 2017	Feb. 05, 2019	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, net			$ 120,199	$ 93,392
Loan reserves			4,685	2,137
Transfer of notes receivable to third party	$ 24,200	$ 200
Other Long-term Liabilities
Accounts, Notes, Loans and Financing Receivable [Line Items]
Transfer of notes receivable to third party			24,400	24,200
Mezzanine & Other Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan reserves			4,685	2,137		$ 2,417
Mezzanine & Other Notes Receivable | Variable Interest Entity, Not Primary Beneficiary
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable			114,300	35,200
Mezzanine & Other Notes Receivable | Variable Interest Entity, Not Primary Beneficiary | Interest Rate Below Market Rate
Accounts, Notes, Loans and Financing Receivable [Line Items]
Notes receivable			12,900	2,100
Notes receivable, discount			1,500	100
Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, net	$ 49,100		50,100
Senior and Subordinated Tranches
Accounts, Notes, Loans and Financing Receivable [Line Items]
Impaired loans, unpaid principal balance			50,100
Impaired Loans | Mezzanine & Other Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan reserves on impaired loans			1,600	1,600
Impaired loans, carrying value			1,700	1,800
Average notes on nonaccrual status			1,800	1,800
Interest income on impaired loans, cash basis method			44	44
Non-impaired Loans | Mezzanine & Other Notes Receivable
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan reserves			$ 300	$ 500
Subsequent event | Senior and Subordinated Tranches
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loan reserves on impaired loans					$ 2,800
Impaired loans, carrying value					50,400
Impaired loans, unpaid principal balance					$ 50,100