Servicing of Residential Loans - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Forward Loans [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Fair value of servicing rights	$ 133.8	$ 142.5
Reverse Loans [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Fair value of servicing rights	$ 11.3	$ 14.1
Minimum [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Adverse Change in assumptions percent	10.00%
Maximum [Member]
Fair Value Measurements Of Financial Instruments [Line Items]
Adverse Change in assumptions percent	20.00%