XML 73 R56.htm IDEA: XBRL DOCUMENT v3.8.0.1
Business - Additional Information (Detail)
$ in Millions
Mar. 10, 2017
USD ($)
Branch
Feb. 29, 2016
USD ($)
Branch
Dec. 31, 2017
Location
Subsidiary
Schedule Of Description Of Company [Line Items]      
Number of inactive subsidiaries | Subsidiary     1
Bank operated banking centers, number | Location     50
Bank operated trust office locations, number | Location     3
Valley Commerce Bancorp [Member]      
Schedule Of Description Of Company [Line Items]      
Total assets of acquired/merger company | $ $ 400    
Number of bank branches acquired | Branch 4    
County Commerce Bank [Member]      
Schedule Of Description Of Company [Line Items]      
Total assets of acquired/merger company | $   $ 253  
Number of bank branches acquired | Branch   4