Loans (Analysis of Impaired Loans) (Details) - Loans, Excluding Purchased Credit Impaired Loans [Member] - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 6,065,903		$ 6,042,304
Recorded Investment of Loans Individually Measured for Specific Impairment	23,329		25,459
Recorded Investment	17,449		17,592
Unpaid Principal Balance	28,046		27,228
Related Allowance	94		761
Average Recorded Investment Impaired Loans	24,394	$ 22,448
Interest Recognized on Impaired Loans	49	36
Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	2,456,672		2,442,772
Recorded Investment of Loans Individually Measured for Specific Impairment	7,788		8,818
Recorded Investment	0		2,414
Unpaid Principal Balance	0		2,484
Related Allowance	0		664
Average Recorded Investment Impaired Loans	8,303	12,103
Interest Recognized on Impaired Loans	19	17
Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	90,473		94,737
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Related Allowance	0		0
One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	169,686		167,403
Recorded Investment of Loans Individually Measured for Specific Impairment	513		529
Recorded Investment	424		435
Unpaid Principal Balance	688		693
Related Allowance	11		12
Average Recorded Investment Impaired Loans	521	975
Interest Recognized on Impaired Loans	2	6
Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	280,992		270,106
Recorded Investment of Loans Individually Measured for Specific Impairment	2,299		708
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Related Allowance	0		0
Average Recorded Investment Impaired Loans	1,504	0
Interest Recognized on Impaired Loans	0	0
Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	1,366,381		1,365,321
Recorded Investment of Loans Individually Measured for Specific Impairment	3,694		4,425
Recorded Investment	533		540
Unpaid Principal Balance	537		544
Related Allowance	26		27
Average Recorded Investment Impaired Loans	4,059	2,080
Interest Recognized on Impaired Loans	1	3
Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	1,107,814		1,054,564
Recorded Investment of Loans Individually Measured for Specific Impairment	3,510		5,414
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Related Allowance	0		0
Average Recorded Investment Impaired Loans	4,462	5,516
Interest Recognized on Impaired Loans	0	7
Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	6,799		11,542
Recorded Investment of Loans Individually Measured for Specific Impairment	0		14
Recorded Investment	0		14
Unpaid Principal Balance	0		102
Related Allowance	0		1
Average Recorded Investment Impaired Loans	7	388
Interest Recognized on Impaired Loans	0	1
Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	107,784		109,293
Recorded Investment of Loans Individually Measured for Specific Impairment	0		336
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Related Allowance	0		0
Average Recorded Investment Impaired Loans	168	562
Interest Recognized on Impaired Loans	0	0
Income Property Multifamily Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	106,227		103,779
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Related Allowance	0		0
Owner Occupied Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	64,365		103,480
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Related Allowance	0		0
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	308,710		319,307
Recorded Investment of Loans Individually Measured for Specific Impairment	5,525		5,215
Recorded Investment	4,923		4,464
Unpaid Principal Balance	5,013		4,558
Related Allowance	57		57
Average Recorded Investment Impaired Loans	5,370	824
Interest Recognized on Impaired Loans	27	$ 2
Impaired Loans With Recorded Allowance [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	5,880		7,867
Unpaid Principal Balance	6,238		8,381
Impaired Loans Without Recorded Allowance [Member] \| Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	7,788		6,404
Unpaid Principal Balance	14,806		12,831
Impaired Loans Without Recorded Allowance [Member] \| Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Impaired Loans Without Recorded Allowance [Member] \| One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	89		94
Unpaid Principal Balance	287		291
Impaired Loans Without Recorded Allowance [Member] \| Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	2,299		708
Unpaid Principal Balance	2,288		687
Impaired Loans Without Recorded Allowance [Member] \| Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	3,161		3,885
Unpaid Principal Balance	3,656		4,148
Impaired Loans Without Recorded Allowance [Member] \| Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	3,510		5,414
Unpaid Principal Balance	6,327		8,102
Impaired Loans Without Recorded Allowance [Member] \| Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Impaired Loans Without Recorded Allowance [Member] \| Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		336
Unpaid Principal Balance	0		336
Impaired Loans Without Recorded Allowance [Member] \| Income Property Multifamily Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Impaired Loans Without Recorded Allowance [Member] \| Owner Occupied Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0
Unpaid Principal Balance	0		0
Impaired Loans Without Recorded Allowance [Member] \| Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	602		751
Unpaid Principal Balance	$ 682		$ 833

The balance of financing receivables that were collectively evaluated for impairment.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953423-111524

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 15
-Subparagraph (c)(1)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5212-111524

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 17
-URI http://asc.fasb.org/extlink&oid=66008989&loc=d3e5258-111524

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
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-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953550-111524

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-URI http://asc.fasb.org/extlink&oid=65880944

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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