Commitments and Contingencies - Schedule of Annualized Base Rent from Leases Subject to Purchase Options (Details) $ in Thousands	Dec. 31, 2017 USD ($) property
Leases with purchase options, annualized base rent receivables in next five years and thereafter
2018 | $	$ 8,534
2019 | $	14,702
2020 | $	14,201
2021 | $	12,402
2022 | $	10,459
Thereafter | $	33,964
Total annualized base rent | $	$ 94,262
Number of properties with purchase options, annualized base rent receivables
2018 | property	8
2019 | property	2
2020 | property	4
2021 | property	6
2022 | property	3
Thereafter | property	22
Total number of properties | property	45