Income Taxes Income Taxes (Deferred Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets related to:
Accounts receivable	$ 2,278	$ 2,061
Inventory	2,631	1,931
Accrued compensation	6,783	2,981
Insurance reserves	11,545	10,778
Stock-based compensation	3,399	2,388
Restructuring reserves	325	365
Other accrued liabilities	1,514	1,149
Federal net operating loss carryforward	16,349	17,372
State net operating loss carryforward	3,882	5,559
Other	1,915	1,633
Deferred tax assets, gross	50,621	46,217
Valuation allowance	(145)	(145)	$ (125)	$ (126)
Total deferred tax assets	50,476	46,072
Deferred tax liabilities related to:
Goodwill and intangibles	(21,946)	(21,030)
Property and equipment	(29,684)	(25,440)
Other assets	(1,880)	(1,370)
Total deferred tax liabilities	53,510	47,840
Net deferred tax (liability) asset	$ (3,034)	$ (1,768)