Merger Transaction (Summary of Merger Transaction) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Feb. 16, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Total Consideration:
Fair value of the Cash Consideration, including redemption of fractional shares, as defined in the Merger Agreement		$ 0	$ 0	$ 94,504
Fair Value of the Stock Consideration		0	0	921,930
Fair value of the Total Merger Consideration		428,939	241,772	$ 1,165,771
Assets Acquired at Fair Value
Goodwill		$ 0	$ 1,605
American Realty Capital - Retail Centers of America, Inc.
Total Consideration:
Fair value of the Cash Consideration, including redemption of fractional shares, as defined in the Merger Agreement	$ 94,504
Fair Value of the Stock Consideration	917,046
Fair value of the Partnership Merger Consideration	2
Fair value of the Class B Consideration	4,882
Fair value of the Total Merger Consideration	1,016,434
Assets Acquired at Fair Value
Land	282,063
Buildings, fixtures and improvements	1,079,944
Acquired intangible lease assets	178,634
Total real estate investments, at fair value	1,540,641
Cash and cash equivalents	21,922
Restricted cash	4,241
Prepaid expenses and other assets	18,959
Goodwill	1,605
Total assets acquired at fair value	1,587,368
Liabilities Assumed at Fair Value
Mortgage notes payable	127,651
Mortgage premiums	4,143
Credit facility	304,000
Market lease liabilities	104,840
Derivatives	203
Accounts payable and accrued expenses	21,291
Deferred rent and other liabilities	8,806
Total liabilities assumed at fair value	570,934
Net assets acquired	$ 1,016,434
Value of the fair value of the stock consideration (in usd per share)	$ 24.00