Allowance for Losses on Loans - Allowance for Credit Losses (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
Dec. 31, 2015	Sep. 30, 2015
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	$ 106,829	$ 114,591
Charge-offs	(2,121)	(14,600)
Recoveries	3,193	19,970
Provision & Transfers	0	(13,132)
Ending Allowance	107,901	106,829
Single-family residential
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	47,347	62,763
Charge-offs	(1,139)	(5,524)
Recoveries	2,466	13,403
Provision & Transfers	(918)	(23,295)
Ending Allowance	47,756	47,347
Construction
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	6,680	6,742
Charge-offs	0	(388)
Recoveries	155	120
Provision & Transfers	179	206
Ending Allowance	7,014	6,680
Construction - custom
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	990	1,695
Charge-offs	(60)	0
Recoveries	0	0
Provision & Transfers	132	(705)
Ending Allowance	1,062	990
Land - acquisition & development
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	5,781	5,592
Charge-offs	0	(38)
Recoveries	35	207
Provision & Transfers	962	20
Ending Allowance	6,778	5,781
Land - consumer lot loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	2,946	3,077
Charge-offs	(408)	(459)
Recoveries	0	221
Provision & Transfers	463	107
Ending Allowance	3,001	2,946
Multi-family
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	5,304	4,248
Charge-offs	0	0
Recoveries	0	220
Provision & Transfers	(257)	836
Ending Allowance	5,047	5,304
Commercial real estate
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	8,960	7,548
Charge-offs	(23)	(1,711)
Recoveries	123	735
Provision & Transfers	1,284	2,388
Ending Allowance	10,344	8,960
Commercial & industrial
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	24,980	16,527
Charge-offs	(248)	(3,354)
Recoveries	1	1,374
Provision & Transfers	(637)	10,433
Ending Allowance	24,096	24,980
HELOC
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	902	928
Charge-offs	(1)	(66)
Recoveries	21	2
Provision & Transfers	(102)	38
Ending Allowance	820	902
Consumer
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	2,939	3,227
Charge-offs	(242)	(3,060)
Recoveries	392	3,688
Provision & Transfers	(1,106)	(916)
Ending Allowance	1,983	2,939
Covered loans
Financing Receivable, Allowance for Credit Losses [Roll Forward]
Beginning Allowance	$ 0	2,244
Charge-offs		0
Recoveries		0
Provision & Transfers		(2,244)
Ending Allowance		$ 0

A valuation allowance for financing receivables that are expected to be uncollectible.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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- Definition

Amount of recovery of financing receivables doubtful of collection that were previously charged off.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(4)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

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- Definition

Amount of direct write-downs of financing receivables charged against the allowance.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (c)(3)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=SL6953423-111524

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- Definition

Financing Receivable, Allowance for Credit Losses, Provision and Transfers

+ References

No definition available.

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