Related-Party Transactions - Additional Information (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Corporate Joint Venture \| Investment Advisory And Management Services Provided To WCO
Related Party Transaction [Line Items]
Fees earned for services provided	$ 0.1	$ 0.4	$ 0.1	$ 0.8
Receivable related to fees earned	0.1		0.1		$ 0.9
Walter Capital Opportunity Corp.
Related Party Transaction [Line Items]
Investment in WCO	8.0		8.0		$ 19.4
Income (losses) relating to investment in WCO	$ (0.1)	$ (0.5)	0.1	(1.0)
Dividend received			$ 11.5	$ 1.0

For an unclassified balance sheet, amount of receivables arising from transactions with related parties.

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