DEBT Narrative 1 (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Mar. 31, 2018 |
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Debt Instrument [Line Items] | ||||
| Interest payments | $ 163.6 | $ 146.1 | $ 138.9 | |
| Amortization of debt issuance costs and debt discount | $ 5.0 | $ 4.4 | $ 4.0 | |
| $1.75 billion revolving credit agreement | ||||
| Debt Instrument [Line Items] | ||||
| Debt Instrument, Maturity Date | Oct. 29, 2020 | Oct. 29, 2019 | ||
| Maximum borrowing capacity | $ 1,750.0 | $ 1,500.0 | ||
| Maximum available for Euro borrowings | 250.0 | |||
| Maximum available for British Pound Borrowings | $ 250.0 | |||
| Line of Credit Facility, Covenant Terms | maximum allowed consolidated debt coverage ratio (as defined in the Revolving Credit Agreement) from 5.00-to-1.00 to 5.50-to-1.00 through the rolling period ending March 31, 2018. Subsequently, the maximum allowed consolidated debt coverage ratio may not exceed 5.00-to-1.00 for any rolling period ending on or after June 30, 2018. If we complete one or more acquisitions for aggregate net consideration of at least $50.0 million, our maximum consolidated debt coverage ratio will increase to 5.50-to-1.00 for two rolling periods. On November 22, 2017, the Revolving Credit Agreement was amended to continue to exclude our $402.5 million fixed-to-floating rate subordinated notes from the definition of consolidated debt for purposes of calculating our consolidated debt coverage ratio through December 31, 2018. The Revolving Credit Agreement also contains customary restrictive covenants, such as limitations on indebtedness, liens, mergers, asset transfers and certain investing activities. | |||
| Current remaining borrowing capacity | $ 853.0 | |||
| Interest rate at period end | 3.20% | |||
| Interest rate during period | 2.80% | |||
| Letters of credit issued | $ 3.7 | |||
| Maximum letters of credit allowed | 400.0 | |||
| Line of Credit Facility, Maximum Letters of Credit Available for Euro Borrowings | 25.0 | |||
| Line of Credit Facility, Maximum Letters of Credit Available for British Pound Borrowings | 25.0 | |||
| Other long-term assets, net | $1.75 billion revolving credit agreement | ||||
| Debt Instrument [Line Items] | ||||
| Deferred issuance costs | $ 3.1 | |||
| Subsequent Event [Member] | $1.75 billion revolving credit agreement | ||||
| Debt Instrument [Line Items] | ||||
| Interest rate increase | 0.25% | |||