CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2015
Cash flows from operating activities:
Net income	$ 44,917	$ 33,220	$ 18,055
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and accretion, net	45,048	35,617	28,882
Stock compensation	10,401	487	258
Provision for loan losses	10,589	4,605	1,465
Recovery for deferred taxes	(6,286)	(230)	(3,896)
Loss on other assets	406	104	6
Loss (Gain) on foreclosed real estate	6	0	(28)
Loss on sale of securities available-for-sale, net	537	326	1,634
Gain on sale of securities held-to-maturity, net	(44)	0	0
Net change in accrued interest receivable	(2,181)	(3,847)	(2,130)
Impairment of intangibles	10,248	0	0
Fair value adjustment of foreclosed real estate	18	0	0
Originations of loans held for sale	(685,934)	0	0
Proceeds from sales of loans held for sale	685,934	0	0
Change in bank-owned life insurance value	(2,216)	(1,656)	(1,225)
Net change in other assets	(23,408)	(1,968)	(672)
Net change in accrued interest payable	1,405	603	(46)
Excess contingent consideration paid	(248)	0	0
Net change in accrued expenses and other liabilities	30,806	11,237	6,911
Net cash provided by operating activities	119,998	78,498	49,214
Cash flows from investing activities:
Purchase of securities available-for-sale	(848,613)	(603,995)	(810,624)
Proceeds from sales of securities available-for-sale	457,306	285,508	566,371
Proceeds from maturities and principal repayments of securities available-for-sale	126,420	116,333	124,558
Purchase of securities held to maturity	(932)	(298,869)	(72,759)
Proceeds from sales of securities held-to-maturity	5,870	0	0
Proceeds from maturities and principal repayments of securities held to maturity	45,615	20,465	9,879
Purchase of bank-owned life insurance	(25,000)	(10,000)	(10,000)
Proceeds from bank-owned life insurance death benefit	0	0	864
Loans purchased	(141,403)	0	0
Proceeds from loans sold	4,720	89	5,462
Net change in loans receivable	(274,840)	(217,985)	(146,111)
Proceeds from sales of foreclosed real estate	200	0	86
Cash paid for acquisitions	(29,425)	0	(125,314)
Cash received upon acquisitions	0	0	9,768
Federal Home Loan Bank stock purchases	(715,891)	(860,902)	(544,324)
Federal Home Loan Bank stock redemptions	702,280	837,800	541,160
Proceeds from the sale of premises and equipment	58	55	2,100
Purchase of premises and equipment	(6,798)	(6,979)	(5,031)
Net cash used in investing activities	(700,433)	(738,480)	(453,915)
Cash flows from financing activities:
Net change in checking, savings, and money market deposits	319,524	737,727	334,375
Net change in time deposits	(2,355)	34,821	(43,382)
Net change in wholesale deposits	476,173	0	0
Net change of FHLB and other borrowings	308,000	100,000	0
Net change in federal funds	(5,000)	452,000	70,000
Net change in securities sold under agreements to repurchase	(565)	(969)	(6,404)
Proceeds from long term debt	0	75,000	0
Payment of debt issuance costs	0	(1,767)	0
Payment of debt extinguishment costs	(772)	0	0
Principal payments on capital lease obligations	(80)	(126)	(116)
Cash dividends paid	(4,839)	(4,389)	(3,493)
Purchase of shares by ESOP	1,174	0	0
Issuance of restricted stock	4	0	0
Proceeds from exercise of stock options and issuance of common stock	650	13,857	51,547
Shares repurchased for tax withholdings on stock compensation	(470)	0	0
Contingent consideration - cash paid	(17,253)	0	0
Net cash provided by financing activities	1,074,191	1,406,154	402,527
Net change in cash and cash equivalents	493,756	746,172	(2,174)
Cash and cash equivalents at beginning of year	773,830	27,658	29,832
Cash and cash equivalents at end of year	1,267,586	773,830	27,658
Interest	16,278	3,488	2,433
Income taxes	20,058	5,898	5,277
Franchise taxes	187	98	98
Other taxes	290	79	48
Loans transferred to foreclosed real estate	440	76	54
Issuance of common shares due to acquisition	(37,296)	0	(24,303)
Contingent consideration - equity	(24,142)	0	0
Capital leases	0	0	(2,259)
Securities transferred from available-for-sale to held to maturity	0	0	310
Purchase of available-for-sale securities accrued, not paid	0	0	(7,877)
Purchase of held-to-maturity securities accrued, not paid	$ 0	$ 0	$ (3,000)