Condensed Consolidated Financial Statements - Additional Information (Detail) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Summary Of Significant Accounting Policies [Line Items]
Amount of off balance sheet settlement funds	$ 254.7	$ 270.0
Level 2 [Member]
Summary Of Significant Accounting Policies [Line Items]
Fair value senior note	$ 308.3	$ 309.8

The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission.

No definition available.

Name:	us-gaap_LongTermDebtFairValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant