Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Interest and dividend income
Loans	$ 414,434	$ 370,444	$ 338,458
Taxable securities	24,262	23,249	22,973
Nontaxable securities	978	230	51
Dividends on securities	1,071	1,201	1,247
Federal funds sold and other	922	574	652
Total interest and dividend income	441,667	395,698	363,381
Interest expense
Deposits	35,035	25,114	23,362
Securities sold under agreements to repurchase	384	519	563
FHLB advances and other borrowings	5,437	4,154	3,631
Related party notes payable	0	0	771
Subordinated debentures and subordinated notes payable	4,464	3,737	1,557
Total interest expense	45,320	33,524	29,884
Net interest income	396,347	362,174	333,497
Provision for loan and lease losses	21,539	16,955	19,041
Net interest income after provision for loan losses	374,808	345,219	314,456
Noninterest income
Service charges and other fees	48,573	46,209	39,134
Wealth management fees	9,118	7,283	7,412
Mortgage banking income, net	7,928	7,261	6,694
Net gain on sale of securities	75	160	310
Net (decrease) increase in fair value of loans at fair value	(65,231)	26,314	36,742
Net realized and unrealized gain (loss) on derivatives	49,900	(48,658)	(62,088)
Other	5,699	3,968	5,686
Total noninterest income	56,062	42,537	33,890
Noninterest expense
Salaries and employee benefits	128,135	109,055	100,646
Data processing	24,514	21,719	19,531
Occupancy expenses, net	16,470	15,759	14,809
Professional fees	15,038	13,572	14,024
Communication expenses	3,774	3,721	4,455
Advertising	3,983	4,267	3,940
Equipment expenses	3,347	3,795	3,905
Net loss recognized on repossessed property and other related expenses	1,749	1,263	5,382
Amortization of core deposits and other intangibles	2,358	3,264	7,110
Acquisition expenses	710	15,692	0
Other	16,565	15,533	12,992
Total noninterest expense	216,643	207,640	186,794
Income before income taxes	214,227	180,116	161,552
Provision for income taxes	69,441	58,863	52,487
Net income	$ 144,786	$ 121,253	$ 109,065
Basic earnings per common share
Weighted average shares outstanding, basic (in shares)	58,770,708	56,563,438	57,455,693
Basic earnings per share (in dollars per share)	$ 2.46	$ 2.14	$ 1.90
Diluted earnings per common share
Weighted average shares outstanding, diluted (in shares)	59,029,382	56,729,350	57,500,878
Diluted earnings per share (in dollars per share)	$ 2.45	$ 2.14	$ 1.90
Dividends per share
Dividends paid	$ 43,474	$ 31,419	$ 20,520
Dividends per share (in dollars per share)	$ 0.74	$ 0.56	$ 0.36