Fair Value Measures - Schedule of assets measured at fair value on a recurring basis (Details) - Fair Value, Measurements, Recurring [Member] - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Assets:
Derivative assets	$ 360	$ 544
Investment in Cole REITs	7,552	7,844
Total assets	7,912	8,388
Derivative liabilities	(11,286)
Level 1 [Member]
Assets:
Derivative assets	0	0
Investment in Cole REITs	0	0
Total assets	0	0
Derivative liabilities	0
Level 2 [Member]
Assets:
Derivative assets	360	544
Investment in Cole REITs	0	0
Total assets	360	544
Derivative liabilities	(11,286)
Level 3 [Member]
Assets:
Derivative assets	0	0
Investment in Cole REITs	7,552	7,844
Total assets	7,552	$ 7,844
Derivative liabilities	$ 0