Related Party Transactions and Arrangements - Asset Management Fees (Details) - ARCT IV Merger [Member] - Advisor [Member] - Asset Management Fee [Member]	12 Months Ended
	Dec. 31, 2016 USD ($) shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($) shares	Dec. 31, 2013 USD ($) shares
Related Party Transaction [Line Items]
Cumulative, pre-tax, non-compounded return	6.00%
Percentage of asset cost	0.1875%
Denominator for calculation of asset management fees (shares)	1
Related party expenses | $	$ 0	$ 0	$ 13,900,000	$ 0
Member Units [Member]
Related Party Transaction [Line Items]
Number of units approved for issuance (shares)				492,483
Stock issued in period (shares)			498,857
Exchange ratio			2.3961