Fair Value Measurements and Financial Instruments Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Jul. 22, 2010
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Defined benefit pension plan assets	$ 11,509	$ 15,216	$ 21,567
Revolving credit facility, noncurrent	67,000	54,500
Senior unsecured notes	24,000	30,000		$ 30,000
Total	90,117	84,633
Quoted prices in active markets, (level 1) [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Defined benefit pension plan assets	8,627	12,422
Significant other observable inputs, (level 2) [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Defined benefit pension plan assets	2,882	2,794
Significant unobservable inputs (level 3) [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Defined benefit pension plan assets	0	0
Fair value measurements, recurring [Member] | Quoted prices in active markets, (level 1) [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Assets invested for self-insurance, classified as other assets, noncurrent	15,492	17,167
Defined benefit pension plan assets	8,627	12,422
Deferred compensation	0	0
Fair value measurements, recurring [Member] | Significant other observable inputs, (level 2) [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Assets invested for self-insurance, classified as other assets, noncurrent	0	0
Defined benefit pension plan assets	2,882	2,794
Deferred compensation	1,837	1,574
Fair value measurements, recurring [Member] | Significant unobservable inputs (level 3) [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Assets invested for self-insurance, classified as other assets, noncurrent	0	0
Defined benefit pension plan assets	0	0
Deferred compensation	0	0
Fair value [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Revolving credit facility, noncurrent	67,000	54,500
Senior unsecured notes	18,509	24,837
Term loans, noncurrent	9,854	7,008
Total	95,363	86,345
Total carrying value [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Revolving credit facility, noncurrent	67,000	54,500
Senior unsecured notes	18,000	24,000
Term loans, noncurrent	7,623	6,604
Total	92,623	85,104
Total carrying value [Member] | Fair value measurements, recurring [Member]
Fair value, assets and liabilities measured on recurring and nonrecurring basis [Line Items]
Assets invested for self-insurance, classified as other assets, noncurrent	15,492	17,167
Defined benefit pension plan assets	11,509	15,216
Deferred compensation	$ 1,837	$ 1,574