Property Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Property Assets (Details) [Abstract]
Furniture and equipment	$ 316,696,000	$ 281,111,000
Transportation equipment	12,204,000	16,083,000
Building and leasehold improvements	311,782,000	292,028,000
Land and land improvements	5,299,000	5,299,000
Construction in progress	61,858,000	55,210,000
Property assets, gross	707,839,000	649,731,000
Accumulated depreciation	(398,039,000)	(362,110,000)
Property assets, net	309,800,000	287,621,000
Capitalized software costs included in construction in progress	54,800,000	47,800,000
Cost of internally developed software placed in service	$ 8,400,000	$ 16,000,000	$ 20,600,000