Commercial Real Estate Loan Types (Detail) - USD ($) $ in Millions	Dec. 31, 2015	Dec. 31, 2014
Commercial Mortgages
Apartment/ Multi-family	$ 770.1	$ 728.7
Office	830.4	735.5
Retail	683.3	854.1
Industrial/ Warehouse	310.5	323.7
Other	442.3	125.7
Total Commercial Mortgages	3,036.6	2,767.7
Construction, Acquisition and Development Loans	392.8	256.8
Single Family Investment	147.4	121.3
Other Commercial Real Estate Related	272.0	187.5
Total Commercial Real Estate Loans	$ 3,848.8	$ 3,333.3