Related Party Transactions and Arrangements - Investment in the Cole REITs Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Related Party Transaction [Line Items]
Aggregate equity investments	$ 46,077	$ 56,824
Net (loss) income	(415)	2,361	$ (77)
Cole REITs [Member]
Related Party Transaction [Line Items]
Aggregate equity investments	4,748
Net (loss) income	(1,300)	46	$ (1,600)
Cole REITs [Member]
Related Party Transaction [Line Items]
Aggregate equity investments	$ 4,700	$ 4,100