Business Acquisition - Fair Value of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions		9 Months Ended
	Sep. 15, 2020	Sep. 30, 2020	Dec. 31, 2019
Business Acquisition [Line Items]
Goodwill		$ 3,617.6	$ 2,361.4
Collateral Analytics and DocVerify
Business Acquisition [Line Items]
Total consideration, net		73.5
Computer software		8.2
Other intangible assets		18.1
Goodwill		46.9
Other current and non-current assets		4.1
Total assets acquired		77.3
Total liabilities assumed		3.8
Net assets acquired		$ 73.5
Optimal Blue Holdco, LLC
Business Acquisition [Line Items]
Total consideration, net	$ 1,798.8
Trade receivables	11.3
Computer software	79.8
Other intangible assets	610.0
Goodwill	1,210.2
Other current and non-current assets	13.7
Total assets acquired	1,925.0
Deferred income taxes	106.5
Current and other non-current liabilities	19.7
Total liabilities assumed	126.2
Net assets acquired	$ 1,798.8