Annual and transition report of foreign private issuers pursuant to Section 13 or 15(d)

Restricted Cash, Deposits and Marketable Securities (Narrative) (Details)

v3.8.0.1
Restricted Cash, Deposits and Marketable Securities (Narrative) (Details)
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Disclosure of financial assets [line items]    
Bonds coupon rate 4.435% 3.389%
Bonds Maturity date Dec. 30, 2020 Dec. 30, 2018
Bonds rating Baa3 Baa3
Annual interest rate 1.50%  
Bottom of range [Member]    
Disclosure of financial assets [line items]    
Annual interest rate   0.75%
Top of range [member]    
Disclosure of financial assets [line items]    
Annual interest rate   1.25%
Forward contract [Member] | Bottom of range [Member]    
Disclosure of financial assets [line items]    
Annual interest rate   0.35%
Forward contract [Member] | Top of range [member]    
Disclosure of financial assets [line items]    
Annual interest rate   0.40%
WACHOVIA [Member]    
Disclosure of financial assets [line items]    
Annual interest rate 5.80%