Commitments and Contingencies - Annualized base rent (Details) $ in Thousands	Dec. 31, 2016 USD ($) item
Leases with purchase options, annualized base rent receivables in next five years and thereafter
Leases with purchase option, annualized base rent receivables in 2017	$ 7,466
Leases with purchase option, annualized base rent receivables in 2019	12,023
Total leases with purchase option, annualized base rent receivables	$ 19,489
Number of properties with purchase options, annualized base rent receivables
Number of properties with a purchase option, annualized base rent receivables in 2017 | item	9
Number of properties with a purchase option, annualized base rent receivables in 2019 | item	12
Total number of properties with a purchase option, annualized base rent receivables | item	21
Mezzanine Loan | Minimum
Number of properties with purchase options, annualized base rent receivables
Secured Financial Acquisition	$ 65,000