Subsequent Events	3 Months Ended
Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events, Policy [Policy Text Block]	Subsequent Events No events occurred requiring disclosure other than the repurchase of an additional 0.9 million shares of our common stock for $16.6 million subsequent to March 31, 2018 through May 10, 2018.

Disclosure of accounting policy for reporting subsequent events.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 235
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=84158767&loc=d3e18780-107790

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