Condensed Combined Balance Sheets of Limited Liabilities Accounted for under Equity Method (Detail) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Equity Method Investments And Joint Ventures [Abstract]
Net property, including CIP		$ 33,111	$ 60,970
Other assets		3,560	4,598
Total assets		36,671	65,568
Other liabilities		3,067	3,334
Mortgage notes payable, non-recourse to us		27,839	28,367
Advances payable to us	[1]		21,638
Equity		5,765	12,229
Total liabilities and equity		36,671	65,568
Our share of equity in and advances to LLCs reflected as:
Investments in LLCs		4,671	13,955
Advances to LLCs			21,638
Investments in and advances to LLCs before amounts included in accrued expenses and other liabilities		4,671	35,593
Amounts included in accrued expenses and other liabilities		(1,895)	(1,862)
Our share of equity in and advances to LLCs, net		$ 2,776	$ 33,731

[1] Consists of a 5.29% member loan to Arlington Medical Properties, LLC, which was fully repaid to us in March, 2017, as discussed above.