Mortgage Note Receivable (Details)		3 Months Ended	12 Months Ended
	Feb. 21, 2018 USD ($) real_estate_property	Mar. 31, 2017	Dec. 31, 2017 USD ($) mortgage_note_receivable	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 28, 2017 USD ($)	Dec. 31, 2014 USD ($)
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of mortgage note receivables | mortgage_note_receivable			1
Mortgage loans on real estate, gross			$ 10,600,000	$ 10,900,000
Mortgage loans on real estate			$ 10,633,000	10,786,000	$ 10,897,000		$ 0
Mortgage loans on real estate, interest rate			9.50%
Funding of notes receivable			$ 13,750,000	12,406,000	10,863,000
Mortgage loans on real estate, face amount of mortgages						$ 11,450,000
Financing receivable, net			13,917,000	0
Acquired Mortgage And Promissory Notes [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, impairment recognized			$ 0
Mortgage Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of mortgage note receivables | mortgage_note_receivable			1
Mortgage loans on real estate, interest rate		11.00%
Receivable with imputed interest, discount			$ 2,700,000
Promissory Notes, Secured by Accounts Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, net			8,750,000
Other Assets [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Interest receivable			600,000	87,000
Interest receivable considered past due			$ 500,000	$ 0
Variable Interest Entity, Not Primary Beneficiary [Member] | Mortgage Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Mortgage loans on real estate					$ 11,000,000
Subsequent Event [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Funding of notes receivable	$ 5,350,000
Subsequent Event [Member] | Promissory Notes, Secured By Facilities Owned By Borrower [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Financing receivable, net	$ 2,200,000
Long-Term Acute Care Facility [Member] | Subsequent Event [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of properties used to secure notes by borrower | real_estate_property	9
Specialty Hospital [Member] | Subsequent Event [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of properties used to secure notes by borrower | real_estate_property	2