Property Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010
Property Assets (Details) [Abstract]
Furniture and equipment	$ 281,111,000	$ 249,392,000
Transportation equipment	16,083,000	14,032,000
Building and leasehold improvements	292,028,000	259,476,000
Land and land improvements	5,299,000	5,299,000
Construction in progress	55,210,000	42,291,000
Property assets, gross	649,731,000	570,490,000
Accumulated depreciation	(362,110,000)	(345,851,000)
Property assets, net	287,621,000	224,639,000
Capitalized software costs included in construction in progress	47,800,000	37,800,000
Cost of internally developed software placed in service	$ 16,000,000	$ 20,600,000