Reserve for Unfunded Commitments - Summary of Activity in Reserve for Unfunded Commitments (Detail) - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2015
Dec. 31, 2014
Dec. 31, 2013
Commitments and Contingencies Disclosure [Abstract]      
Balance at beginning of period $ 2,145 $ 2,415 $ 3,615
Acquisitions   125  
Provision for losses - Unfunded commitments 330 (395) (1,200)
Balance at end of period $ 2,475 $ 2,145 $ 2,415