VARIABLE INTEREST ENTITIES, Not the Primary Beneficiary - Aggregate Assets, Liabilities Exposure to Loss (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Sep. 30, 2014
LIHTC funds - not primary beneficiary
Variable interest entity, nonconsolidated, carrying amount of assets and liabilities [Abstract]
Aggregate assets	$ 3,220,560	$ 2,988,224
Aggregate liabilities	949,538	899,586
Our risk of loss	49,655	48,915
NMTC funds - not primary beneficiary
Variable interest entity, nonconsolidated, carrying amount of assets and liabilities [Abstract]
Aggregate assets	65,560	83,474
Aggregate liabilities	35	2
Our risk of loss	12	13
Other real estate limited partnerships and LLCs - not primary beneficiary
Variable interest entity, nonconsolidated, carrying amount of assets and liabilities [Abstract]
Aggregate assets	29,523	30,202
Aggregate liabilities	37,062	36,262
Our risk of loss	172	183
Total VIEs - not primary beneficiary
Variable interest entity, nonconsolidated, carrying amount of assets and liabilities [Abstract]
Aggregate assets	3,315,643	3,101,900
Aggregate liabilities	986,635	935,850
Our risk of loss	$ 49,839	$ 49,111