Loans - Credit risk profile by risk grade of acquired credit impaired loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Jun. 30, 2019
Loans
Total loans	$ 11,375,104	$ 11,226,192
Construction and land development
Loans
Total loans	1,017,261	957,346
Commercial loans | Commercial and industrial
Loans
Total loans	1,386,327	1,271,464
Consumer | Real estate
Loans
Total loans	3,464,980	3,540,500
Consumer | Consumer
Loans
Total loans	663,422	641,746
Acquired credit impaired loans
Loans
Total loans	361,846	424,584
Acquired credit impaired loans | Pass
Loans
Total loans	218,364	256,105
Acquired credit impaired loans | Special mention
Loans
Total loans	58,281	69,770
Acquired credit impaired loans | Substandard
Loans
Total loans	85,201	98,709
Acquired credit impaired loans | Commercial loans | Real estate
Loans
Total loans	130,938	164,540
Acquired credit impaired loans | Commercial loans | Real estate | Pass
Loans
Total loans	108,762	132,852
Acquired credit impaired loans | Commercial loans | Real estate | Special mention
Loans
Total loans	6,465	13,811
Acquired credit impaired loans | Commercial loans | Real estate | Substandard
Loans
Total loans	15,711	17,877
Acquired credit impaired loans | Commercial loans | Construction and land development
Loans
Total loans	25,032	27,014
Acquired credit impaired loans | Commercial loans | Construction and land development | Pass
Loans
Total loans	17,756	18,665
Acquired credit impaired loans | Commercial loans | Construction and land development | Special mention
Loans
Total loans	2,904	3,181
Acquired credit impaired loans | Commercial loans | Construction and land development | Substandard
Loans
Total loans	4,372	5,168
Acquired credit impaired loans | Commercial loans | Commercial and industrial
Loans
Total loans	7,029	10,198
Acquired credit impaired loans | Commercial loans | Commercial and industrial | Pass
Loans
Total loans	5,160	6,389
Acquired credit impaired loans | Commercial loans | Commercial and industrial | Special mention
Loans
Total loans	286	508
Acquired credit impaired loans | Commercial loans | Commercial and industrial | Substandard
Loans
Total loans	1,583	3,301
Acquired credit impaired loans | Consumer | Real estate
Loans
Total loans	163,359	184,208
Acquired credit impaired loans | Consumer | Real estate | Pass
Loans
Total loans	82,203	93,303
Acquired credit impaired loans | Consumer | Real estate | Special mention
Loans
Total loans	35,968	39,020
Acquired credit impaired loans | Consumer | Real estate | Substandard
Loans
Total loans	45,188	51,885
Acquired credit impaired loans | Consumer | Consumer
Loans
Total loans	35,488	38,624
Acquired credit impaired loans | Consumer | Consumer | Pass
Loans
Total loans	4,483	4,896
Acquired credit impaired loans | Consumer | Consumer | Special mention
Loans
Total loans	12,658	13,250
Acquired credit impaired loans | Consumer | Consumer | Substandard
Loans
Total loans	$ 18,347	$ 20,478