BUSINESS COMBINATION - PROFORMA (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Dec. 31, 2016	Dec. 31, 2015
Pro-forma Combined
Operating revenue	$ 1,974.2	$ 2,076.4
Net income	$ 84.9	$ 107.7
Basic Earnings Per Share (in dollars per share)	$ 1.97	$ 2.48
Diluted Earnings Per Share (in dollars per share)	$ 1.95	$ 2.45
Weighted Average Number of Shares Outstanding:
Basic	43.1	43.5
Diluted	43.5	44.0

The pro forma basic net income per share for a period as if the business combination or combinations had been completed at the beginning of a period.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (h)(2)-(3)
-URI http://asc.fasb.org/extlink&oid=56956515&loc=d3e1392-128463

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The pro forma income from continuing operations before changes in accounting and extraordinary items, net of tax effect, for the period as if the business combination or combinations had been completed at the beginning of a period.

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The pro forma revenue for a period as if the business combination or combinations had been completed at the beginning of the period.

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