Short and Long-Term Debt and Commitments Related to Letters of Credit (Tables)

12 Months Ended

Dec. 31, 2016

Debt Disclosure [Abstract]

Schedule of short-term debt [Table Text Block]

Short-term debt consisted of the following:

	December 31,
	2016		2015
Current portion of long-term debt	$	16,701	$	15,501

Schedule of long-term debt instruments [Table Text Block]

Long-term debt consisted of the following:

	December 31,
	2016		2015
Revolving credit facility
Swing-line borrowings	$	10,000	$	2,500
LIBOR borrowings	57,000		52,000
	67,000		54,500
Senior unsecured notes	24,000		30,000
Term loans	16,151		16,105
	107,151		100,605
Less debt issuance costs	333		471
Less current portion	16,701		15,501
	$	90,117	$	84,633