Fair Value Measurements and Financial Instruments (Tables)

3 Months Ended

Mar. 31, 2018

Fair Value Disclosures [Abstract]

Assets and liabilities measured at fair value on a recurring basis [Table Text Block]

Our assets and liabilities measured at fair value on a recurring basis at March 31, 2018 were as follows:

			Fair Value Measurements at March 31, 2018 Using:
Assets and Liabilities Recorded at Fair Value on a Recurring Basis	Total Carrying Value at March 31, 2018		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Assets invested for self-insurance, classified as other assets, noncurrent	$	20,905	$	20,905	$	—	$	—
Liabilities:
Deferred compensation	$	2,318	$	—	$	2,318	$	—

N. Fair Value Measurements and Financial Instruments (continued)

Our assets and liabilities measured at fair value on a recurring basis at December 31, 2017 were as follows:

			Fair Value Measurements at December 31, 2017 Using:
Assets and Liabilities Recorded at Fair Value on a Recurring Basis	Total Carrying Value at December 31, 2017		Quoted Prices in Active Markets (Level 1)		Significant Other Observable Inputs (Level 2)		Significant Unobservable Inputs (Level 3)
Assets:
Assets invested for self-insurance, classified as other assets, noncurrent	$	19,422	$	19,422	$	—	$	—
Liabilities:
Deferred compensation	$	2,146	$	—	$	2,146	$	—

Financial instruments recorded at historical carrying value [Table Text Block]

Financial instruments classified as noncurrent liabilities and their carrying values and fair values were as follows:

	March 31, 2018				December 31, 2017
	Carrying Value		Fair Value		Carrying Value		Fair Value
Revolving credit facility, noncurrent	$	128,500	$	128,500	$	100,000	$	100,000
Senior unsecured notes	12,000		12,291		12,000		12,389
Term loans, noncurrent	6,583		7,545		7,935		10,038
Total	$	147,083	$	148,336	$	119,935	$	122,427