Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
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| Statement of Comprehensive Income [Abstract] | |||
| Unrealized gain (loss) on available-for-sale securities, (provision) benefit | $ 0.1 | $ 0.0 | $ 0.2 |
| Unrealized gain (loss) on interest rate swaps, tax (provision) benefit | $ 0.0 | $ 0.0 | $ 0.0 |
| X | ||||||||||
- Definition Amount of tax expense (benefit), before reclassification adjustments, related to increase (decrease) in accumulated gain (loss) from derivative instruments designated and qualifying as the effective portion of cash flow hedges and an entity's share of an equity investee's increase (decrease) in deferred hedging gain (loss). Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- Definition Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities. Reference 1: http://www.xbrl.org/2003/role/presentationRef
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| X | ||||||||||
- References No definition available.
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