Commitments and Contingencies - Summary of Allowance for Loan Repurchases or Indemnifications (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Commitments And Contingencies Disclosure [Abstract]
Balance at beginning of period	$ 2,859	$ 1,457	$ 2,156	$ 828
Provision for loan repurchases or indemnifications	470	392	1,173	1,021
Losses on loans repurchased or indemnified	13		13
Balance at end of period	$ 3,342	$ 1,849	$ 3,342	$ 1,849