Significant Accounting Policies Self-Insurance Workers' Compensation (Details) - Workers' Compensation [Member] - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Liability for Claims and Claims Adjustment Expense [Line Items]
Self Insurance Reserve	$ 19,664	$ 18,276
Stop-Loss Insurance limit per claim [Member]
Liability for Claims and Claims Adjustment Expense [Line Items]
Self Insurance Limits	500
Stop-Loss Insurance limit per claim [Member] | TEXAS
Liability for Claims and Claims Adjustment Expense [Line Items]
Self Insurance Limits	750
Loss-Sensitive limit per claim [Member] [Member] | Other states, except California, Texas and Washington [Domain]
Liability for Claims and Claims Adjustment Expense [Line Items]
Self Insurance Limits	$ 350