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 |