XML 83 R42.htm IDEA: XBRL DOCUMENT v3.8.0.1
Committed Lines of Credit (Tables)
12 Months Ended
Dec. 31, 2017
Short-term Debt [Abstract]  
Schedule of Line of Credit Facilities [Table Text Block]
 
2017
 
2016
Balance outstanding at end of period
$
105,000

 
$
120,000

Letters of credit outstanding at end of period
$
34,420

 
$
34,353

Average interest rate at end of period
2.26
%
 
1.50
%