| Leases - Summary of Supplemental Cash Flow Information Related to Leases (Detail) $ in Millions | 3 Months Ended | 
|---|---|
| Mar. 31, 2019  USD ($) | |
| Cash paid for amounts included in the measurement of lease liabilities: | |
| Operating cash flows for operating leases | $ 10.2 | 
| Financing cash flows for finance leases | 0.1 | 
| Right-of-use assets obtained in exchange for new lease liabilities: | |
| Operating leases | $ 6.1 | 
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- Definition Cash paid for amounts included in the measurement of lease liabilities. No definition available. 
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| X | ||||||||||
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- Definition Right-of-use assets obtained in exchange for new lease liabilities. No definition available. 
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- Definition Amount of cash outflow for principal payment on finance lease. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use. Reference 1: http://www.xbrl.org/2003/role/disclosureRef 
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- Definition Amount of increase in right-of-use asset obtained in exchange for operating lease liability. Reference 1: http://www.xbrl.org/2003/role/exampleRef 
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