SECURITIES (Details) - USD ($) $ in Thousands	12 Months Ended
Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2014
Available-for-sale debt securities [Abstract]
Mortgage-backed securities available-for-sale	$ 558,940	$ 576,583
Available-for-sale equity securities [Abstract]
Fair value	910,309	679,504
Available-for-sale securities [Abstract]
Amortized cost	1,435,272	1,254,661
Gross unrealized gains	37,257	10,377
Gross unrealized (losses)	(3,280)	(8,951)
Total securities	1,469,249	1,256,087
Amortized Cost	1,435,272	1,254,661
Fair Value	1,469,249	1,256,087
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	151,949	545,994
OVER 12 MONTHS, Fair Value	52,770	103,450
TOTAL, Fair Value	204,719	649,444
LESS THAN 12 MONTHS, Unrealized (Losses)	(1,033)	(5,161)
OVER 12 MONTHS, Unrealized (Losses)	(2,247)	(3,790)
TOTAL, Unrealized (Losses)	(3,280)	(8,951)
AMORTIZED COST [Abstract]
Due in one year or less	0	0
Due after one year through five years	17,370	1,174
Due after five years through ten years	426,034	370,087
Due after ten years	436,077	302,596
Total Amortized Cost	879,481	673,857
Mortgage-backed securities	555,036	580,165
Common equities and mutual funds	755	639
Amortized cost	1,435,272	1,254,661
FAIR VALUE [Abstract]
Due in one year or less	0	0
Due after one year through five years	17,897	1,207
Due after five years through ten years	446,771	376,394
Due after ten years	444,516	300,989
Total Fair Value	909,184	678,590
Common equities and mutual funds	1,125	914
Total securities	1,469,249	1,256,087
Summary of activities related to the sale of available for sale securities [Abstract]
Proceeds from sales	285,508	566,371	$ 166,804
Gross gains on sales	1,459	2,753	2,292
Gross losses on sales	1,785	4,387	$ 2,185
Held-to-maturity Securities [Abstract]
Amortized cost	619,853	345,744
Gross unrealized gains	12,807	2,182
Gross unrealized (losses)	(86)	(1,079)
Fair value	632,574	346,847
Held-to-maturity securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	24,264	89,700
OVER 12 MONTHS, Fair Value	2,256	72,695
TOTAL, Fair Value	26,520	162,395
LESS THAN 12 MONTHS, Unrealized (Losses)	(55)	(442)
OVER 12 MONTHS, Unrealized (Losses)	(31)	(637)
TOTAL, Unrealized (Losses)	(86)	(1,079)
AMORTIZED COST [Abstract]
Due in one year or less	472	95
Due after one year through five years	12,502	8,411
Due after five years through ten years	157,944	140,145
Due after ten years	315,177	130,516
Total Amortized Cost	486,095	279,167
Mortgage-backed securities	133,758	66,577
Amortized cost	619,853	345,744
FAIR VALUE [Abstract]
Due in one year or less	471	96
Due after one year through five years	12,696	8,430
Due after five years through ten years	163,806	140,505
Due after ten years	321,166	131,712
Total Fair Value	498,139	280,743
Mortgage-backed securities	134,435	66,104
Total securities	632,574	346,847
Trust Preferred Securities [Member]
Available-for-sale securities [Abstract]
Amortized cost	14,936	14,930
Total securities	12,978	12,667
Amortized Cost	14,936	14,930
Fair Value	12,978	12,667
Unrealized Gain (Loss)	(1,958)	(2,263)
AMORTIZED COST [Abstract]
Amortized cost	14,936	14,930
FAIR VALUE [Abstract]
Total securities	12,978	12,667
S&P Credit Rating, BB+ [Member] \| Moody's Credit Rating, Baa2 [Member] \| Key Corp Capital I [Member] \| Trust Preferred Securities [Member]
Available-for-sale securities [Abstract]
Amortized cost	4,987	4,986
Total securities	4,189	4,189
Amortized Cost	4,987	4,986
Fair Value	4,189	4,189
Unrealized Gain (Loss)	(798)	(797)
AMORTIZED COST [Abstract]
Amortized cost	4,987	4,986
FAIR VALUE [Abstract]
Total securities	4,189	4,189
S&P Credit Rating, BB [Member] \| Moody's Credit Rating, Baa2 [Member] \| Huntington Capital Trust II SE [Member] \| Trust Preferred Securities [Member]
Available-for-sale securities [Abstract]
Amortized cost	4,981	4,979
Total securities	4,077	4,076
Amortized Cost	4,981	4,979
Fair Value	4,077	4,076
Unrealized Gain (Loss)	(904)	(903)
AMORTIZED COST [Abstract]
Amortized cost	4,981	4,979
FAIR VALUE [Abstract]
Total securities	4,077	4,076
Standard & Poor's, BBB- Rating [Member] \| Moody's Credit Rating, Baa1 [Member] \| PNC Capital Trust [Member] \| Trust Preferred Securities [Member]
Available-for-sale securities [Abstract]
Amortized cost	4,968	4,965
Total securities	4,712	4,402
Amortized Cost	4,968	4,965
Fair Value	4,712	4,402
Unrealized Gain (Loss)	(256)	(563)
AMORTIZED COST [Abstract]
Amortized cost	4,968	4,965
FAIR VALUE [Abstract]
Total securities	4,712	4,402
Trust preferred and corporate securities [Member]
Available-for-sale debt securities [Abstract]
Amortized cost	14,935	16,199
Gross unrealized gains	0	8
Gross unrealized (losses)	(1,957)	(2,263)
Mortgage-backed securities available-for-sale	12,978	13,944
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	0
OVER 12 MONTHS, Fair Value	12,978
TOTAL, Fair Value	12,978
LESS THAN 12 MONTHS, Unrealized (Losses)	0
OVER 12 MONTHS, Unrealized (Losses)	(1,957)
TOTAL, Unrealized (Losses)	(1,957)
Small Business Administration Securities [Member]
Available-for-sale debt securities [Abstract]
Amortized cost	78,431	54,493
Gross unrealized gains	2,288	1,563
Gross unrealized (losses)	0	0
Mortgage-backed securities available-for-sale	80,719	56,056
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value		0
OVER 12 MONTHS, Fair Value		12,667
TOTAL, Fair Value		12,667
LESS THAN 12 MONTHS, Unrealized (Losses)		0
OVER 12 MONTHS, Unrealized (Losses)		(2,263)
TOTAL, Unrealized (Losses)		(2,263)
Non-Bank Qualified Obligation of States And Political Subdivisions [Member]
Available-for-sale debt securities [Abstract]
Amortized cost	668,628	603,165
Gross unrealized gains	30,141	7,240
Gross unrealized (losses)	(97)	(1,815)
Mortgage-backed securities available-for-sale	698,672	608,590
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	8,481	97,006
OVER 12 MONTHS, Fair Value	2,688	42,583
TOTAL, Fair Value	11,169	139,589
LESS THAN 12 MONTHS, Unrealized (Losses)	(58)	(860)
OVER 12 MONTHS, Unrealized (Losses)	(39)	(955)
TOTAL, Unrealized (Losses)	(97)	(1,815)
Asset-backed Securities [Member]
Available-for-sale debt securities [Abstract]
Amortized cost	117,487
Gross unrealized gains	73
Gross unrealized (losses)	(745)
Mortgage-backed securities available-for-sale	116,815
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	89,403
OVER 12 MONTHS, Fair Value	0
TOTAL, Fair Value	89,403
LESS THAN 12 MONTHS, Unrealized (Losses)	(745)
OVER 12 MONTHS, Unrealized (Losses)	0
TOTAL, Unrealized (Losses)	(745)
Collateralized Mortgage Backed Securities [Member]
Available-for-sale debt securities [Abstract]
Amortized cost	555,036	580,165
Gross unrealized gains	4,382	1,283
Gross unrealized (losses)	(478)	(4,865)
Mortgage-backed securities available-for-sale	558,940	576,583
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	54,065	448,988
OVER 12 MONTHS, Fair Value	36,979	48,079
TOTAL, Fair Value	91,044	497,067
LESS THAN 12 MONTHS, Unrealized (Losses)	(230)	(4,301)
OVER 12 MONTHS, Unrealized (Losses)	(248)	(564)
TOTAL, Unrealized (Losses)	(478)	(4,865)
Debt Securities [Member]
Available-for-sale debt securities [Abstract]
Amortized cost	1,434,517	1,254,022
Gross unrealized gains	36,884	10,094
Gross unrealized (losses)	(3,277)	(8,943)
Mortgage-backed securities available-for-sale	1,468,124	1,255,173
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	151,949	545,994
OVER 12 MONTHS, Fair Value	52,645	103,329
TOTAL, Fair Value	204,594	649,323
LESS THAN 12 MONTHS, Unrealized (Losses)	(1,033)	(5,161)
OVER 12 MONTHS, Unrealized (Losses)	(2,244)	(3,782)
TOTAL, Unrealized (Losses)	(3,277)	(8,943)
Common Equities And Mutual Funds [Member]
Available-for-sale equity securities [Abstract]
Amortized cost	755	639
Gross unrealized gains	373	283
Gross unrealized (losses)	(3)	(8)
Fair value	1,125	914
Available-for-sale securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	0	0
OVER 12 MONTHS, Fair Value	125	121
TOTAL, Fair Value	125	121
LESS THAN 12 MONTHS, Unrealized (Losses)	0	0
OVER 12 MONTHS, Unrealized (Losses)	(3)	(8)
TOTAL, Unrealized (Losses)	(3)	(8)
US States and Political Subdivisions Debt Securities [Member]
Held-to-maturity Securities [Abstract]
Amortized cost	20,626	19,540
Gross unrealized gains	355	60
Gross unrealized (losses)	(44)	(187)
Fair value	20,937	19,413
Held-to-maturity securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	2,909	5,528
OVER 12 MONTHS, Fair Value	2,256	7,964
TOTAL, Fair Value	5,165	13,492
LESS THAN 12 MONTHS, Unrealized (Losses)	(13)	(34)
OVER 12 MONTHS, Unrealized (Losses)	(31)	(153)
TOTAL, Unrealized (Losses)	(44)	(187)
AMORTIZED COST [Abstract]
Amortized cost	20,626	19,540
FAIR VALUE [Abstract]
Total securities	20,937	19,413
Non-Bank Qualified Obligation of States And Political Subdivisions [Member]
Held-to-maturity Securities [Abstract]
Amortized cost	465,469	259,627
Gross unrealized gains	11,744	2,122
Gross unrealized (losses)	(11)	(419)
Fair value	477,202	261,330
Held-to-maturity securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	1,294	78,663
OVER 12 MONTHS, Fair Value	0	4,136
TOTAL, Fair Value	1,294	82,799
LESS THAN 12 MONTHS, Unrealized (Losses)	(11)	(365)
OVER 12 MONTHS, Unrealized (Losses)	0	(54)
TOTAL, Unrealized (Losses)	(11)	(419)
AMORTIZED COST [Abstract]
Amortized cost	465,469	259,627
FAIR VALUE [Abstract]
Total securities	477,202	261,330
Collateralized Mortgage Backed Securities [Member]
Held-to-maturity Securities [Abstract]
Amortized cost	133,758	66,577
Gross unrealized gains	708	0
Gross unrealized (losses)	(31)	(473)
Fair value	134,435	66,104
Held-to-maturity securities in a continuous unrealized loss position [Abstract]
LESS THAN 12 MONTHS, Fair Value	20,061	5,509
OVER 12 MONTHS, Fair Value	0	60,595
TOTAL, Fair Value	20,061	66,104
LESS THAN 12 MONTHS, Unrealized (Losses)	(31)	(43)
OVER 12 MONTHS, Unrealized (Losses)	0	(430)
TOTAL, Unrealized (Losses)	(31)	(473)
AMORTIZED COST [Abstract]
Amortized cost	133,758	66,577
FAIR VALUE [Abstract]
Total securities	$ 134,435	$ 66,104

Amount of available-for-sale equity securities at cost, net of adjustments, that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the cost over several maturity groupings. Adjustments include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.

No definition available.