Allowance for Loan Losses - Recorded Investment Disaggregated on Basis of Impairment (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	$ 30,691	$ 30,231
Loans collectively evaluated for impairment	2,280,875	2,102,512
Total Gross Loans Receivable	2,403,724	2,252,014
One-to-four Family Residential
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	277	245
Loans collectively evaluated for impairment	65,151	63,572
Total Gross Loans Receivable	70,577	69,530
PCI Loans
Schedule of loan receivables on the basis of impairment method
PCI loans	92,158
PCI Loans | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	92,158	119,271
PCI Loans | One-to-four Family Residential
Schedule of loan receivables on the basis of impairment method
PCI loans	5,149
PCI Loans | One-to-four Family Residential | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	5,149	5,713
Commercial Business
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	24,567	23,016
Loans collectively evaluated for impairment	1,829,556	1,692,569
Total Gross Loans Receivable	1,925,533	1,809,075
Commercial Business | Commercial and Industrial
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	8,843	11,374
Loans collectively evaluated for impairment	593,826	533,905
Total Gross Loans Receivable	618,390	570,453
Commercial Business | Owner-occupied Commercial Real Estate
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	5,150	3,913
Loans collectively evaluated for impairment	573,493	554,199
Total Gross Loans Receivable	603,372	594,986
Commercial Business | Non-owner Occupied Commercial Real Estate
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	10,574	7,729
Loans collectively evaluated for impairment	662,237	604,465
Total Gross Loans Receivable	703,771	643,636
Commercial Business | PCI Loans
Schedule of loan receivables on the basis of impairment method
PCI loans	71,410
Commercial Business | PCI Loans | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	71,410	93,490
Commercial Business | PCI Loans | Commercial and Industrial
Schedule of loan receivables on the basis of impairment method
PCI loans	15,721
Commercial Business | PCI Loans | Commercial and Industrial | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	15,721	25,174
Commercial Business | PCI Loans | Owner-occupied Commercial Real Estate
Schedule of loan receivables on the basis of impairment method
PCI loans	24,729
Commercial Business | PCI Loans | Owner-occupied Commercial Real Estate | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	24,729	36,874
Commercial Business | PCI Loans | Non-owner Occupied Commercial Real Estate
Schedule of loan receivables on the basis of impairment method
PCI loans	30,960
Commercial Business | PCI Loans | Non-owner Occupied Commercial Real Estate | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	30,960	31,442
Real Estate Construction and Land Development
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	5,683	6,759
Loans collectively evaluated for impairment	109,780	97,060
Total Gross Loans Receivable	123,073	114,115
Real Estate Construction and Land Development | One-to-four Family Residential
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	3,699	4,703
Loans collectively evaluated for impairment	41,667	38,961
Total Gross Loans Receivable	49,745	49,195
Real Estate Construction and Land Development | Five or More Family Residential and Commercial Properties
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	1,984	2,056
Loans collectively evaluated for impairment	68,113	58,099
Total Gross Loans Receivable	73,328	64,920
Real Estate Construction and Land Development | PCI Loans
Schedule of loan receivables on the basis of impairment method
PCI loans	7,610
Real Estate Construction and Land Development | PCI Loans | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	7,610	10,296
Real Estate Construction and Land Development | PCI Loans | One-to-four Family Residential
Schedule of loan receivables on the basis of impairment method
PCI loans	4,379
Real Estate Construction and Land Development | PCI Loans | One-to-four Family Residential | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	4,379	5,531
Real Estate Construction and Land Development | PCI Loans | Five or More Family Residential and Commercial Properties
Schedule of loan receivables on the basis of impairment method
PCI loans	3,231
Real Estate Construction and Land Development | PCI Loans | Five or More Family Residential and Commercial Properties | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	3,231	4,765
Consumer
Schedule of loan receivables on the basis of impairment method
Loans individually evaluated for impairment	164	211
Loans collectively evaluated for impairment	276,388	249,311
Total Gross Loans Receivable	284,541	259,294
Consumer | PCI Loans
Schedule of loan receivables on the basis of impairment method
PCI loans	7,989
Consumer | PCI Loans | Receivables Acquired with Deteriorated Credit Quality
Schedule of loan receivables on the basis of impairment method
PCI loans	$ 7,989	$ 9,772