Income Taxes (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Related Party Transaction [Line Items]
Period that Company cannot be qualified as REIT once fails qualification test	4 years
Income tax assets excluding those from TRS	$ 122,448	$ 169,602
Income tax liabilities excluding those from TRS	55,718	79,308
Net operating loss carryforward for federal income tax purposes	7,631	7,599	6,289
TRS Lessee [Member]
Related Party Transaction [Line Items]
Net operating loss carryforward for federal income tax purposes	$ 20,200