Income Taxes (Income Tax Benefit (Expense) Reconciliation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Tax Disclosure [Abstract]
Federal expense at statutory tax rate	$ (70,894)	$ (64,887)	$ (54,818)
Nontaxable income of NNN	69,651	63,353	53,178
State taxes, net of federal benefit	(141)	(196)	(200)
Amortization of built-in gain tax	0	372	761
Expiration of built-in gain tax	316	1,792	0
Built-in gain tax liability	0	(58)	(6)
Built-in gain tax liability (1)	(197)	0	0
TRS revocation	(4,363)	0	0
Valuation allowance (increase) decrease	(5,047)	(619)	0
Total expense for income taxes	$ (10,675)	$ (243)	$ (1,085)