Acquisition - Summary of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Mar. 08, 2019	Jun. 30, 2019	Dec. 31, 2018
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents		$ 189,400	$ 196,552
Interest-earning deposits greater than 90 days		2,750	3,185
Securities available for sale		1,223,052	721,369
Fixed assets		58,888	32,109
Accrued interest receivable		27,008	16,069
Intangible assets		29,201	8,553
Deposits		5,559,338	4,587,985
Subordinated debentures		141,100	118,156
Accrued interest payable		2,701	1,977
Other liabilities		50,850	40,290
Goodwill		$ 211,251	$ 117,345
As Recorded by Trinity
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	$ 13,899
Interest-earning deposits greater than 90 days	100
Securities available for sale	428,715
Loans	705,057
Other real estate	5,284
Other investments	6,673
Fixed assets	27,586
Accrued interest receivable	3,997
Intangible assets	0
Deferred tax assets	10,708
Other assets	35,045
Total assets acquired	1,237,064
Deposits	1,081,151
Subordinated debentures	26,806
Federal Home Loan Bank advances	6,800
Accrued interest payable	370
Other liabilities	5,842
Total liabilities assumed	1,120,969
Net assets acquired	116,095
Adjustments
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	0
Interest-earning deposits greater than 90 days	0
Securities available for sale	(619)
Loans	(20,743)
Other real estate	(772)
Other investments	0
Fixed assets	(300)
Accrued interest receivable	0
Intangible assets	23,066
Deferred tax assets	(1,057)
Other assets	(5,008)
Total assets acquired	(5,433)
Deposits	36
Subordinated debentures	(3,972)
Federal Home Loan Bank advances	171
Accrued interest payable	0
Other liabilities	(827)
Total liabilities assumed	(4,592)
Net assets acquired	(841)
TCC
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and cash equivalents	13,899
Interest-earning deposits greater than 90 days	100
Securities available for sale	428,096
Loans	684,314
Other real estate	4,512
Other investments	6,673
Fixed assets	27,286
Accrued interest receivable	3,997
Intangible assets	23,066
Deferred tax assets	9,651
Other assets	30,037
Total assets acquired	1,231,631
Deposits	1,081,187
Subordinated debentures	22,834
Federal Home Loan Bank advances	6,971
Accrued interest payable	370
Other liabilities	5,015
Total liabilities assumed	1,116,377
Net assets acquired	115,254
Cash	37,275
Common stock	171,885
Total consideration paid	209,160
Goodwill	$ 93,906
TCC | Core deposit
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Useful life	10 years