Fair Value of Financial Instruments - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Fair Value Disclosures [Abstract]
Net gain from change in fair value of mortgage loans	$ 2.6	$ 1.1

Net Gains Losses From Change In Fair Value Of Mortgages Loans Held For Sale

No definition available.

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