Income Taxes (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current:
State	$ 576	$ 600	$ 375
Total	576	600	375
Income tax provision	576	600	375
Reconciliation of effective tax rate and the U.S. federal statutory income tax rate
Taxes at statutory U.S. federal income tax rate (as a percent)	35.00%	35.00%	35.00%
Nontaxable income of SNH (as a percent)	(35.00%)	(35.00%)	(35.00%)
State and local income taxes, net of federal tax benefit (as a percent)	0.30%	0.40%	0.30%
Change in valuation allowance (as a percent)	6.39%	3.49%	2.40%
Other differences, net (as a percent)	(6.39%)	(3.49%)	(2.40%)
Effective tax rate (as a percent)	0.30%	0.40%	0.30%
Deferred tax assets:
Deferred revenue	2,724	2,655
Tax loss carry forwards	17,266	7,373
Deferred tax assets, gross	20,196	10,360
Valuation allowance	(20,196)	(10,203)
Deferred tax assets, net		157
Deferred tax liabilities:
Depreciable assets		(157)
Percentage of valuation allowance provided	100.00%	100.00%
Net operating loss carry forwards for federal income tax purposes	$ 43,710