Accounts Receivable, Net and Supplemental Balance Sheet Information Accounts Receivable, Net and Supplemental Balance Sheet Information(Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Accounts receivable, net
Accounts receivable	$ 93,156	$ 105,044
Receivables under contractual arrangements	14,309	12,961
Accounts receivable, gross, current	107,465	118,005
Less allowances for doubtful accounts	2,209	2,442
Accounts receivable, net	105,256	115,563
Other current assets
Refundable income taxes	5,317	0
Deferred income taxes	7,715	8,815
Other	813	2,593
Other current assets, total	13,845	11,408
Other assets, noncurrent
Assets invested for self-insurance	12,716	10,758
Investment--cost-method affiliate	1,168	1,168
Deferred income taxes	0	1,059
Other	3,033	1,299
Other assets, noncurrent, total	16,917	14,284
Accrued expenses
Employee compensation	18,578	17,888
Accrued compensated absences	6,953	7,080
Self-insured medical claims	2,503	2,571
Customer advances, deposits	2,191	1,346
Income taxes payable	0	2,013
Taxes, other than income	5,730	2,463
Other	903	1,101
Accrued expenses, total	36,858	34,462
Other liabilities, noncurrent
Pension and retirement plans	7,760	14,513
Deferred income taxes	2,564	0
Other	1,956	3,367
Other liabilities, noncurrent, total	$ 12,280	$ 17,880