Loans (Analysis of Impaired Loans) (Details) - Loans, Excluding Purchased Credit Impaired Loans [Member] - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 6,088,745		$ 6,088,745		$ 5,618,041
Recorded Investment of Loans Individually Measured for Specific Impairment	18,248		18,248		16,080
Recorded Investment	13,160		13,160		14,726
Unpaid Principal Balance	22,531		22,531		19,547
Related Allowance	1,300		1,300		653
Average Recorded Investment Impaired Loans	18,556	$ 20,293	20,502	$ 23,946
Interest Recognized on Impaired Loans	54	91	125	612
Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	2,520,876		2,520,876		2,257,168
Recorded Investment of Loans Individually Measured for Specific Impairment	6,783		6,783		5,524
Recorded Investment	1,208		1,208		690
Unpaid Principal Balance	1,277		1,277		718
Related Allowance	873		873		321
Average Recorded Investment Impaired Loans	6,909	6,507	9,506	8,602
Interest Recognized on Impaired Loans	15	3	48	10
Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	97,537		97,537		94,948
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0		0
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	0	0	0	1
Interest Recognized on Impaired Loans	0	0	0	0
One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	165,394		165,394		172,150
Recorded Investment of Loans Individually Measured for Specific Impairment	546		546		1,286
Recorded Investment	358		358		314
Unpaid Principal Balance	591		591		339
Related Allowance	353		353		314
Average Recorded Investment Impaired Loans	617	3,315	796	3,238
Interest Recognized on Impaired Loans	5	11	8	35
Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	239,313		239,313		213,158
Recorded Investment of Loans Individually Measured for Specific Impairment	708		708		0
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	708	0	354	118
Interest Recognized on Impaired Loans	0	0	0	0
Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	1,376,349		1,376,349		1,308,673
Recorded Investment of Loans Individually Measured for Specific Impairment	2,433		2,433		2,106
Recorded Investment	546		546		0
Unpaid Principal Balance	551		551		0
Related Allowance	28		28		0
Average Recorded Investment Impaired Loans	1,939	2,061	2,010	3,114
Interest Recognized on Impaired Loans	8	10	19	27
Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	1,043,849		1,043,849		940,261
Recorded Investment of Loans Individually Measured for Specific Impairment	3,746		3,746		6,055
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	4,486	6,665	5,001	7,302
Interest Recognized on Impaired Loans	0	65	0	533
Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	11,950		11,950		14,283
Recorded Investment of Loans Individually Measured for Specific Impairment	102		102		467
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	103	825	245	685
Interest Recognized on Impaired Loans	1	1	4	4
Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	116,970		116,970		119,813
Recorded Investment of Loans Individually Measured for Specific Impairment	336		336		562
Recorded Investment	0		0		335
Unpaid Principal Balance	0		0		335
Related Allowance	0		0		3
Average Recorded Investment Impaired Loans	449	893	506	670
Interest Recognized on Impaired Loans	0	0	0	0
Income Property Multifamily Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	89,373		89,373		83,634
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0		0
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Owner Occupied Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	110,853		110,853		81,671
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0		0
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	316,281		316,281		332,282
Recorded Investment of Loans Individually Measured for Specific Impairment	3,594		3,594		80
Recorded Investment	2,976		2,976		15
Unpaid Principal Balance	3,010		3,010		15
Related Allowance	46		46		15
Average Recorded Investment Impaired Loans	3,345	27	2,084	216
Interest Recognized on Impaired Loans	25	$ 1	46	$ 3
Impaired Loans With Recorded Allowance [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	5,088		5,088		1,354
Unpaid Principal Balance	5,429		5,429		1,407
Impaired Loans Without Recorded Allowance [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	5,575		5,575		4,834
Unpaid Principal Balance	11,840		11,840		6,455
Impaired Loans Without Recorded Allowance [Member] | Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Impaired Loans Without Recorded Allowance [Member] | One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	188		188		972
Unpaid Principal Balance	402		402		1,397
Impaired Loans Without Recorded Allowance [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	708		708		0
Unpaid Principal Balance	687		687		0
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	1,887		1,887		2,106
Unpaid Principal Balance	2,124		2,124		2,311
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	3,746		3,746		6,055
Unpaid Principal Balance	6,340		6,340		8,528
Impaired Loans Without Recorded Allowance [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	102		102		467
Unpaid Principal Balance	102		102		490
Impaired Loans Without Recorded Allowance [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	336		336		227
Unpaid Principal Balance	336		336		227
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Impaired Loans Without Recorded Allowance [Member] | Consumer Portfolio Segment [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	618		618		65
Unpaid Principal Balance	$ 700		$ 700		$ 139