Real Estate (Dispositions) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense	$ (75)		$ 74		$ (6,891)
Assets Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of sold properties	25		0		0
Gain on disposition of real estate	11,587		173		0
Income tax expense	(318)		(66)		0
Gain on disposition of real estate, net of income tax expense	11,269		107		0
Gain (Loss) on Disposition of Assets, Total, Continuing and Discontinued Operations	11,424		5,595		10,956
Assets Held-for-sale | Discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain on disposition of real estate	155	[1]	6,272	[1]	10,956	[1]
Income tax expense	$ 0		$ (784)		$ 0
Number of sold properties	2		35		34

[1] Amount includes the recognition of deferred gains on previously sold properties.