XML 47 R37.htm IDEA: XBRL DOCUMENT v3.19.2
Acquisition (Details)
$ in Thousands
Nov. 30, 2017
USD ($)
banking_offices
Jun. 30, 2019
USD ($)
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
Business Acquisition [Line Items]        
Goodwill   $ 201,116 $ 201,116  
Diboll State Bancshares, Inc.        
Business Acquisition [Line Items]        
Voting interests acquired 100.00%      
Number of branches | banking_offices 17      
Acquisition, Total merger consideration $ 224,300      
Acquisition, Loans 621,300      
Acquisition, Investment securities 234,400      
Acquisition, Deposits 899,300      
Goodwill   $ 109,600   $ 109,700
Core Deposits | Diboll State Bancshares, Inc.        
Business Acquisition [Line Items]        
Acquisition, Finite-lived intangible assets $ 14,700      
Amortization period 9 years      
Trust Relationship Intangible | Diboll State Bancshares, Inc.        
Business Acquisition [Line Items]        
Acquisition, Finite-lived intangible assets $ 5,400      
Amortization period 13 years