Schedule III - Real Estate and Accumulated Depreciation (Details 2) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Jan. 01, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Federal income tax purposes	$ 1,400,000,000
Real Estate:
Beginning balance	1,840,306,000	1,805,434,000	1,596,338,000
Additions to/improvements of real estate	97,302,000	51,998,000	229,399,000
Assets sold/written-off	(2,052,000)	(17,126,000)	(20,303,000)
Ending balance	1,935,556,000	1,840,306,000	1,805,434,000
Accumulated Depreciation
Beginning balance	217,428,000	174,055,000	138,813,000
Depreciation expense	50,616,000	49,026,000	40,705,000
Assets sold/written-off	(1,196,000)	(5,653,000)	(5,463,000)
Ending balance	$ 266,848,000	$ 217,428,000	$ 174,055,000
Land improvements
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Useful life	7 years
Building
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Useful life	50 years
Buildings and improvements | Minimum
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Useful life	7 years
Buildings and improvements | Maximum
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Useful life	15 years
Leasehold improvements
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
Useful life	15 years