Loans (Analysis of Impaired Loans) (Details) - Loans, Excluding Purchased Credit Impaired Loans [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2016
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 6,253,549		$ 6,253,549		$ 6,042,304
Recorded Investment of Loans Individually Measured for Specific Impairment	39,672		39,672		25,459
Recorded Investment	23,675		23,675		17,592
Unpaid Principal Balance	32,557		32,557		27,228
Related Allowance	3,499		3,499		761
Average Recorded Investment Impaired Loans	31,500	$ 23,840	29,486	$ 21,253
Interest Recognized on Impaired Loans	301	48	346	74
Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	2,580,972		2,580,972		2,442,772
Recorded Investment of Loans Individually Measured for Specific Impairment	23,392		23,392		8,818
Recorded Investment	10,275		10,275		2,414
Unpaid Principal Balance	10,275		10,275		2,484
Related Allowance	3,425		3,425		664
Average Recorded Investment Impaired Loans	15,590	12,859	13,332	10,414
Interest Recognized on Impaired Loans	50	20	69	33
Unsecured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	95,419		95,419		94,737
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
One-to-Four Family Residential [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	170,271		170,271		167,403
Recorded Investment of Loans Individually Measured for Specific Impairment	783		783		529
Recorded Investment	320		320		435
Unpaid Principal Balance	574		574		693
Related Allowance	4		4		12
Average Recorded Investment Impaired Loans	648	676	608	879
Interest Recognized on Impaired Loans	21	(3)	22	3
Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	280,721		280,721		270,106
Recorded Investment of Loans Individually Measured for Specific Impairment	2,799		2,799		708
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	2,549	354	1,936	236
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	1,352,109		1,352,109		1,365,321
Recorded Investment of Loans Individually Measured for Specific Impairment	3,658		3,658		4,425
Recorded Investment	525		525		540
Unpaid Principal Balance	530		530		544
Related Allowance	25		25		27
Average Recorded Investment Impaired Loans	3,676	1,749	3,925	1,868
Interest Recognized on Impaired Loans	7	10	6	14
Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	1,127,370		1,127,370		1,054,564
Recorded Investment of Loans Individually Measured for Specific Impairment	3,397		3,397		5,414
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	3,453	5,102	4,107	5,420
Interest Recognized on Impaired Loans	192	0	192	0
Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	6,049		6,049		11,542
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0		14
Recorded Investment	0		0		14
Unpaid Principal Balance	0		0		102
Related Allowance	0		0		1
Average Recorded Investment Impaired Loans	0	206	5	293
Interest Recognized on Impaired Loans	0	1	0	3
Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment of Loans Collectively Measured for Contingency Provision	133,167		133,167		109,293
Recorded Investment of Loans Individually Measured for Specific Impairment	0		0		336
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Related Allowance	0		0		0
Average Recorded Investment Impaired Loans	0	562	112	562
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	153,529		153,529		103,779
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	39,466		39,466		103,480
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	314,476		314,476		319,307
Recorded Investment of Loans Individually Measured for Specific Impairment	5,643		5,643		5,215
Recorded Investment	4,877		4,877		4,464
Unpaid Principal Balance	4,920		4,920		4,558
Related Allowance	45		45		57
Average Recorded Investment Impaired Loans	5,584	2,332	5,461	1,581
Interest Recognized on Impaired Loans	31	$ 20	57	$ 21
Impaired Loans With Recorded Allowance [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	15,997		15,997		7,867
Unpaid Principal Balance	16,299		16,299		8,381
Impaired Loans Without Recorded Allowance [Member] | Secured Loans [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	13,117		13,117		6,404
Unpaid Principal Balance	18,238		18,238		12,831
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	463		463		94
Unpaid Principal Balance	908		908		291
Impaired Loans Without Recorded Allowance [Member] | Commercial Land [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	2,799		2,799		708
Unpaid Principal Balance	2,787		2,787		687
Impaired Loans Without Recorded Allowance [Member] | Income Property Multifamily [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	3,133		3,133		3,885
Unpaid Principal Balance	3,422		3,422		4,148
Impaired Loans Without Recorded Allowance [Member] | Owner Occupied [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	3,397		3,397		5,414
Unpaid Principal Balance	6,297		6,297		8,102
Impaired Loans Without Recorded Allowance [Member] | Land And Acquisition [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0		0
Unpaid Principal Balance	0		0		0
Impaired Loans Without Recorded Allowance [Member] | Residential Construction [Member]
Financing Receivable, Recorded Investment [Line Items]
Recorded Investment	0		0		336
Unpaid Principal Balance	0		0		336
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	766		766		751
Unpaid Principal Balance	$ 905		$ 905		$ 833