Other Assets (Detail) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Other Assets [Abstract]
Other assets	$ 91,379	$ 69,644
Loan servicing assets, at fair value
Other Assets [Abstract]
Other assets	29,621	21,398
Prepaid expenses
Other Assets [Abstract]
Other assets	21,084	16,960
Other investments
Other Assets [Abstract]
Other assets	10,411	10,372
Servicer reserve receivable
Other Assets [Abstract]
Other assets	9,043	4,938
Accounts receivable
Other Assets [Abstract]
Other assets	8,889	7,572
Insurance reimbursement receivable
Other Assets [Abstract]
Other assets	7,119	0
Receivable from investors
Other Assets [Abstract]
Other assets	1,394	1,566
Due from related parties
Other Assets [Abstract]
Other assets	279	476
Tenant improvement receivable
Other Assets [Abstract]
Other assets	0	3,290
Other
Other Assets [Abstract]
Other assets	$ 3,539	$ 3,072