Commitments and Contingencies Level 4 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Loss Contingencies [Line Items]
Operating Leases, Rent Expense	$ 30,500	$ 31,900	$ 33,300
Operating Leases, Future Minimum Payments Due, Current	13,683
Operating Leases, Future Minimum Payments, Due in Two Years	10,889
Operating Leases, Future Minimum Payments, Due in Three Years	9,461
Operating Leases, Future Minimum Payments, Due in Four Years	8,404
Operating Leases, Future Minimum Payments, Due in Five Years	7,739
Operating Leases, Future Minimum Payments, Due Thereafter	59,473
Operating Leases, Future Minimum Payments Due	109,649
Capital Leases, Future Minimum Payments Due, Current	58,678
Capital Leases, Future Minimum Payments Due in Two Years	30,528
Capital Leases, Future Minimum Payments Due in Three Years	36,344
Capital Leases, Future Minimum Payments Due in Four Years	32,690
Capital Leases, Future Minimum Payments Due in Five Years	11,044
Capital Leases, Future Minimum Payments Due Thereafter	27,948
Capital Leases, Future Minimum Payments Due	197,232
Capital Leases, Future Minimum Payments, Interest Included in Payments	(30,694)
Capital Leases, Future Minimum Payments, Net Minimum Payments	166,538
Agreements, Future Payments, Due in One Year	7,438
Agreements, Future Payments, Due in Two Years	6,446
Agreements, Future Payments, Due in Three Years	4,461
Agreements, Future Payments, Due in Four Years	3,078
Agreements, Future Payments, Due in Five Years	2,132
Agreements, Future Payments, Due in Six Years and Thereafter	4,232
Agreements, Future Payments Due	27,787
Self Insurance Reserve	78,200	$ 78,000
Employment Agreement [Member]
Loss Contingencies [Line Items]
Agreements, Future Payments, Due in One Year	1,796
Agreements, Future Payments, Due in Two Years	1,257
Agreements, Future Payments, Due in Three Years	609
Agreements, Future Payments, Due in Four Years	307
Agreements, Future Payments, Due in Five Years	51
Agreements, Future Payments, Due in Six Years and Thereafter	0
Agreements, Future Payments Due	4,020
Consulting Agreement [Member]
Loss Contingencies [Line Items]
Agreements, Future Payments, Due in One Year	412
Agreements, Future Payments, Due in Two Years	367
Agreements, Future Payments, Due in Three Years	258
Agreements, Future Payments, Due in Four Years	217
Agreements, Future Payments, Due in Five Years	146
Agreements, Future Payments, Due in Six Years and Thereafter	255
Agreements, Future Payments Due	1,655
Noncompete Agreements [Member]
Loss Contingencies [Line Items]
Agreements, Future Payments, Due in One Year	5,230
Agreements, Future Payments, Due in Two Years	4,822
Agreements, Future Payments, Due in Three Years	3,594
Agreements, Future Payments, Due in Four Years	2,554
Agreements, Future Payments, Due in Five Years	1,935
Agreements, Future Payments, Due in Six Years and Thereafter	3,977
Agreements, Future Payments Due	$ 22,112
Minimum [Member]
Loss Contingencies [Line Items]
Management, consulting and non-compete agreement term	5 years
Maximum [Member]
Loss Contingencies [Line Items]
Management, consulting and non-compete agreement term	10 years