Consolidated Statements of Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Interest Income
Loans	$ 123,432	$ 109,993	$ 245,763	$ 217,674
Investment securities	9,957	7,013	19,145	14,055
Federal funds sold and other	497	227	1,039	458
Total interest income	133,886	117,233	265,947	232,187
Interest Expense
Deposits	27,098	12,658	50,892	23,656
FHLB advances and other borrowings	1,923	2,815	3,926	4,978
Subordinated debentures and subordinated notes payable	1,390	1,207	2,760	2,377
Total interest expense	30,411	16,680	57,578	31,011
Net interest income	103,475	100,553	208,369	201,176
Provision for loan and lease losses	7,673	4,900	12,888	9,457
Net interest income after provision for loan and lease losses	95,802	95,653	195,481	191,719
Noninterest Income
Service charges and other fees	10,209	12,047	21,897	25,224
Wealth management fees	2,117	2,335	4,358	4,519
Mortgage banking income, net	991	1,166	2,311	2,826
Net loss on sale of securities	0	(8)	(513)	(9)
Net increase (decrease) in fair value of loans at fair value	14,018	(14,838)	33,234	(23,502)
Net realized and unrealized (loss) gain on derivatives	(11,032)	14,282	(29,348)	21,509
Other	1,920	3,758	3,004	4,849
Total noninterest income	18,223	18,742	34,943	35,416
Noninterest Expense
Salaries and employee benefits	34,537	33,672	69,307	66,539
Data processing and communication	5,964	9,190	11,242	16,074
Occupancy and equipment	5,539	5,290	10,665	10,138
Professional fees	3,970	4,027	7,258	8,267
Advertising	1,216	1,121	2,154	2,181
Net loss on repossessed property and other related expenses	404	1,000	3,467	1,214
Other	4,950	4,844	9,593	9,599
Total noninterest expense	56,580	59,144	113,686	114,012
Income before income taxes	57,445	55,251	116,738	113,123
Provision for income taxes	12,934	14,719	26,441	43,361
Net income	$ 44,511	$ 40,532	$ 90,297	$ 69,762
Basic earnings per common share
Weighted average shares outstanding (in shares)	56,994,817	58,941,315	57,484,838	58,921,972
Earnings per share (in dollars per share)	$ 0.78	$ 0.69	$ 1.57	$ 1.18
Diluted earnings per common share
Weighted average shares outstanding (in shares)	57,074,674	59,146,117	57,556,984	59,116,923
Diluted earnings per share (in dollars per share)	$ 0.78	$ 0.69	$ 1.57	$ 1.18
Dividends per share
Dividends paid	$ 14,235	$ 11,780	$ 28,771	$ 23,550
Dividends per share (in dollars per share)	$ 0.25	$ 0.20	$ 0.50	$ 0.40