Loans - Schedule of Ending Balances of Loans and the Related Allowance by Segment and Class (Details) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	$ 21,472	$ 21,090	$ 21,151	$ 21,097	$ 20,986	$ 21,292
Allowance for loan losses, Loans individually evaluated for impairment	421		1,543
Allowance for loan losses, Loans collectively evaluated	20,591		18,881
Allowance for loan losses, Total	21,472		21,151
Total loans receivable, PCI	2,422,837		2,320,874
Total loans receivable, Loans individually evaluated for impairment	16,868		20,942
Total loans receivable, Loans collectively evaluated	2,405,969		2,299,932
Total loans	2,446,823		2,352,415
Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	460	566	727	474	336	361
Total loans receivable, PCI	23,986		31,541
Retail Consumer Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	8,172	8,191	8,585	8,879	9,813	11,549
Total loans	1,218,867		1,202,479
Retail Consumer Loans | One to four family loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	228		863
Allowance for loan losses, Loans collectively evaluated	3,490		3,585
Allowance for loan losses, Total	3,844		4,476
Total loans receivable, PCI	662,626		676,020
Total loans receivable, Loans individually evaluated for impairment	8,336		10,305
Total loans receivable, Loans collectively evaluated	654,290		665,715
Total loans	670,036		684,089
Retail Consumer Loans | One to four family loans | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	126		28
Total loans receivable, PCI	7,410		8,069
Retail Consumer Loans | Indirect auto finance
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	0		1
Allowance for loan losses, Loans collectively evaluated	1,083		880
Allowance for loan losses, Total	1,083		881
Total loans receivable, PCI	160,664		140,879
Total loans receivable, Loans individually evaluated for impairment	0		1
Total loans receivable, Loans collectively evaluated	160,664		140,878
Total loans	160,664		140,879
Retail Consumer Loans | Indirect auto finance | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	0		0
Total loans receivable, PCI	0		0
Retail Consumer Loans | Consumer loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	5		8
Allowance for loan losses, Loans collectively evaluated	56		49
Allowance for loan losses, Total	61		57
Total loans receivable, PCI	11,315		7,882
Total loans receivable, Loans individually evaluated for impairment	5		8
Total loans receivable, Loans collectively evaluated	11,310		7,874
Total loans	11,317		7,900
Retail Consumer Loans | Consumer loans | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	0		0
Total loans receivable, PCI	2		18
Retail Consumer Loans | HELOCs - originated
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	6		44
Allowance for loan losses, Loans collectively evaluated	1,244		1,340
Allowance for loan losses, Total	1,250		1,384
Total loans receivable, PCI	142,792		156,780
Total loans receivable, Loans individually evaluated for impairment	453		12
Total loans receivable, Loans collectively evaluated	142,339		156,768
Total loans	143,049		157,068
Retail Consumer Loans | HELOCs - originated | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	0		0
Total loans receivable, PCI	257		288
Retail Consumer Loans | HELOCs - purchased
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	0		0
Allowance for loan losses, Loans collectively evaluated	821		838
Allowance for loan losses, Total	821		838
Total loans receivable, PCI	165,680		162,407
Total loans receivable, Loans individually evaluated for impairment	0		0
Total loans receivable, Loans collectively evaluated	165,680		162,407
Total loans	165,680		162,407
Retail Consumer Loans | HELOCs - purchased | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	0		0
Total loans receivable, PCI	0		0
Retail Consumer Loans | Construction and land/lots
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	21		88
Allowance for loan losses, Loans collectively evaluated	1,218		889
Allowance for loan losses, Total	1,239		977
Total loans receivable, PCI	67,666		49,608
Total loans receivable, Loans individually evaluated for impairment	595		634
Total loans receivable, Loans collectively evaluated	67,071		48,974
Total loans	68,121		50,136
Retail Consumer Loans | Construction and land/lots | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	0		0
Total loans receivable, PCI	455		528
Commercial Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	12,840	$ 12,333	11,839	$ 11,744	$ 10,837	$ 9,382
Total loans	1,227,956		1,149,936
Commercial Loans | Commercial real estate
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	149		239
Allowance for loan losses, Loans collectively evaluated	7,911		6,600
Allowance for loan losses, Total	8,228		7,351
Total loans receivable, PCI	799,061		713,025
Total loans receivable, Loans individually evaluated for impairment	4,457		6,284
Total loans receivable, Loans collectively evaluated	794,604		706,741
Total loans	810,332		730,408
Commercial Loans | Commercial real estate | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	168		512
Total loans receivable, PCI	11,271		17,383
Commercial Loans | Construction and development loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	9		13
Allowance for loan losses, Loans collectively evaluated	2,989		2,982
Allowance for loan losses, Total	3,149		3,166
Total loans receivable, PCI	181,742		195,337
Total loans receivable, Loans individually evaluated for impairment	2,380		2,184
Total loans receivable, Loans collectively evaluated	179,362		193,153
Total loans	184,179		197,966
Commercial Loans | Construction and development loans | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	151		171
Total loans receivable, PCI	2,437		2,629
Commercial Loans | Commercial and industrial
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	3		287
Allowance for loan losses, Loans collectively evaluated	1,302		1,221
Allowance for loan losses, Total	1,320		1,524
Total loans receivable, PCI	130,183		117,761
Total loans receivable, Loans individually evaluated for impairment	642		1,514
Total loans receivable, Loans collectively evaluated	129,541		116,247
Total loans	132,337		120,387
Commercial Loans | Commercial and industrial | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	15		16
Total loans receivable, PCI	2,154		2,626
Commercial Loans | Municipal leases
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, Loans individually evaluated for impairment	0		0
Allowance for loan losses, Loans collectively evaluated	477		497
Allowance for loan losses, Total	477		497
Total loans receivable, PCI	101,108		101,175
Total loans receivable, Loans individually evaluated for impairment	0		0
Total loans receivable, Loans collectively evaluated	101,108		101,175
Total loans	101,108		101,175
Commercial Loans | Municipal leases | Purchased Credit Impaired (PCI) Loans
Financing Receivable, Allowance for Credit Losses [Line Items]
Allowance for loan losses, PCI	0		0
Total loans receivable, PCI	$ 0		$ 0