Income Taxes (Income Tax Benefit (Expense) Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Federal expense at statutory tax rate	$ 0	$ 0	$ (70,894)
Nontaxable income of NNN	0	0	69,651
State taxes, net of federal benefit	0	0	(141)
Expiration of built-in gain tax	0	0	316
Loss carry forwards increases (decrease)	(2,019)	55	0
Built-in gain tax liability	134	22	(197)
TRS Revocation Election	0	0	(4,363)
Valuation allowance (increase) decrease	1,885	(77)	(5,047)
Total expense for income taxes	$ 0	$ 0	$ (10,675)