DEBT Senior Unsecured Notes (Tables)

3 Months Ended

Mar. 31, 2018

Senior Notes 2016 [Member]

Debt Instrument [Line Items]

Schedule of Debt [Table Text Block]

The maturity and interest rates of the 2016 Notes are as follows:

	Amount		Maturity Date	Interest Rate
Series A	$	100,000	October 20, 2028	2.75	%
Series B	100,000		October 20, 2033	3.03	%
Series C	100,000		October 20, 2037	3.27	%
Series D	50,000		October 20, 2041	3.52	%

Senior Notes 2015 [Member]

Debt Instrument [Line Items]

Schedule of Debt [Table Text Block]

The maturity and interest rates of the 2015 Notes are as follows:

	Amount		Maturity Date	Interest Rate
Series A	$	100,000	August 20, 2025	3.15	%
Series B	100,000		August 20, 2030	3.35	%
Series C	50,000		April 1, 2035	3.61	%
Series D	100,000		April 1, 2045	4.02	%