Real Estate (Dispositions) (Details) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2015 USD ($) property	Sep. 30, 2014 USD ($) property		Sep. 30, 2015 USD ($) property	Sep. 30, 2014 USD ($) property
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense	$ (545)	$ (372)		$ (491)	$ (721)
Assets Held-for-sale
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of sold properties - gain on disposition of real estate | property	5	10		14	22
Gain on disposition of real estate	$ 1,970	$ 3,464		$ 9,231	$ 8,472
Income tax expense	(56)	(108)		(86)	(306)
Gain on disposition of real estate, net of income tax expense	1,914	3,356		9,145	8,166
Gain on disposition of real estate included in discontinued operations, net of income tax expense	$ 1,914	$ 3,499		$ 9,145	$ 8,321
Assets Held-for-sale | Discontinued Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of sold properties - gain on disposition of real estate included in discontinued operations | property	0	0		0	2
Gain on disposition of real estate	$ 0	$ 143	[1]	$ 0	$ 155	[1]

[1] Amount includes deferred gain on previously sold properties.