Summary of Significant Accounting Policies (Details) ft² in Millions, $ in Billions	Mar. 31, 2018 USD ($) ft² state property
Business Overview:
Gross investment amount, total | $	$ 3.8
Number of real estate properties | property	196
Number of states that the Company owns real estate in, whole units | state	27
Square footage of owned real estate properties	14.5
Approximate square feet for which Nationwide property management services provided by company	10.9