Property and Equipment (Details) (USD $)	3 Months Ended
Mar. 31, 2013	Dec. 31, 2012
Property and Equipment
Total property and equipment	$ 911,717,000	$ 827,097,000
Less accumulated depreciation	(126,993,000)	(114,775,000)
Total	784,724,000	712,322,000
Net increase in total property and equipment	84,600,000
Buildings and improvements
Property and Equipment
Total property and equipment	567,754,000	498,984,000
Land
Property and Equipment
Total property and equipment	289,466,000	289,903,000
Fixtures and equipment
Property and Equipment
Total property and equipment	17,597,000	14,554,000
Construction in process
Property and Equipment
Total property and equipment	30,959,000	17,809,000
Capitalized internal use software
Property and Equipment
Total property and equipment	$ 5,941,000	$ 5,847,000

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Gross amount of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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- Definition

Amount, net of accumulated depreciation, depletion and amortization, of long-lived physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, furniture and fixtures, and computer equipment.

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