Unconsolidated Affiliates - Schedule of Equity in Earnings of Unconsolidated Affiliates (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($)
Schedule of Investments [Line Items]
Equity in earnings of unconsolidated affiliates	$ 2.1
International Financial Data Services L.P. [Member]
Schedule of Investments [Line Items]
Equity in earnings of unconsolidated affiliates	2.9
Pershing Road Development Company, LLC [Member]
Schedule of Investments [Line Items]
Equity in earnings of unconsolidated affiliates	0.2
Broadway Square Partners, LLP [Member]
Schedule of Investments [Line Items]
Equity in earnings of unconsolidated affiliates	(1.5)
Other Unconsolidated Affiliates [Member]
Schedule of Investments [Line Items]
Equity in earnings of unconsolidated affiliates	$ 0.5