VARIABLE INTEREST ENTITIES, Not the Primary Beneficiary - Aggregate Assets, Liabilities Exposure to Loss (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015	Sep. 30, 2014
LIHTC funds - not primary beneficiary
Variable interest entity, nonconsolidated, carrying amount of assets and liabilities [Abstract]
Aggregate assets	$ 3,266,464	$ 2,988,224
Aggregate liabilities	946,849	899,586
Our risk of loss	20,033	48,915
NMTC funds - not primary beneficiary
Variable interest entity, nonconsolidated, carrying amount of assets and liabilities [Abstract]
Aggregate assets	65,503	83,474
Aggregate liabilities	30	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	29,671	30,202
Aggregate liabilities	36,369	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	3,361,638	3,101,900
Aggregate liabilities	983,248	935,850
Our risk of loss	$ 20,217	$ 49,111