Income Taxes (Schedule of Components of Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Deferred tax assets:
Allowance for doubtful accounts	$ 1,944	$ 1,885
Tax credits	5,606	7,179
Other accruals	105,894	97,247
Net operating losses	0	346
Other	14,770	14,784
Total deferred tax assets	128,214	121,441
Deferred tax liabilities:
Inventories	62,846	55,965
Property and equipment	140,019	122,354
Other	30,915	28,528
Total deferred tax liabilities	233,780	206,847
Net deferred tax liabilities	$ (105,566)	$ (85,406)