Annual report pursuant to Section 13 and 15(d)

Premises and Equipment - Summary of Major Components of Premises and Equipment (Detail)

v3.8.0.1
Premises and Equipment - Summary of Major Components of Premises and Equipment (Detail) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Property, Plant and Equipment [Line Items]      
Premises and equipment, gross $ 59,452 $ 60,444  
Accumulated depreciation and amortization (32,797) (31,383)  
Impairment reserve 0 (363)  
Total premises and equipment, net 26,655 28,698  
Depreciation and amortization expense 2,900 2,900 $ 3,100
Software [Member]      
Property, Plant and Equipment [Line Items]      
Premises and equipment, gross 879 880  
Land [Member]      
Property, Plant and Equipment [Line Items]      
Premises and equipment, gross 8,470 8,750  
Buildings and improvements [Member]      
Property, Plant and Equipment [Line Items]      
Premises and equipment, gross 17,261 18,313  
Furniture and equipment [Member]      
Property, Plant and Equipment [Line Items]      
Premises and equipment, gross 21,271 20,668  
Leasehold improvements [Member]      
Property, Plant and Equipment [Line Items]      
Premises and equipment, gross $ 11,571 $ 11,833