Allowance for Loan Losses - Recorded Investment Segregated by Amounts Individually or Collectively in Allowance for Loan Losses (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	$ 982,341	$ 984,346
Balance, end of period: Individually evaluated for impairment	31,085	31,714
Balance, end of period: Collectively evaluated for impairment	951,256	952,632
Commercial
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	342,857	341,091
Balance, end of period: Individually evaluated for impairment	19,383	24,189
Balance, end of period: Collectively evaluated for impairment	323,474	316,902
Real estate construction one-to-four family
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	36,286	36,828
Balance, end of period: Individually evaluated for impairment	2,423	0
Balance, end of period: Collectively evaluated for impairment	33,863	36,828
Real estate construction other
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	72,421	71,658
Balance, end of period: Individually evaluated for impairment	0	0
Balance, end of period: Collectively evaluated for impairment	72,421	71,658
Real estate term owner occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	129,491	125,795
Balance, end of period: Individually evaluated for impairment	5,786	5,253
Balance, end of period: Collectively evaluated for impairment	123,705	120,542
Real estate term non-owner occupied
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	314,663	324,198
Balance, end of period: Individually evaluated for impairment	1,213	760
Balance, end of period: Collectively evaluated for impairment	313,450	323,438
Real estate term other
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	43,598	41,746
Balance, end of period: Individually evaluated for impairment	1,695	1,063
Balance, end of period: Collectively evaluated for impairment	41,903	40,683
Consumer secured by 1st deeds of trust
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	18,721	19,234
Balance, end of period: Individually evaluated for impairment	585	449
Balance, end of period: Collectively evaluated for impairment	18,136	18,785
Consumer other
Financing Receivable, Allowance for Credit Losses [Line Items]
Balance, end of period	24,304	23,796
Balance, end of period: Individually evaluated for impairment	0	0
Balance, end of period: Collectively evaluated for impairment	$ 24,304	$ 23,796

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No definition available.

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- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 11B
-Subparagraph (h)
-URI http://asc.fasb.org/extlink&oid=84173941&loc=SL6953423-111524

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- Definition

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

+ References

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- Definition

Amount before allowance of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Includes deferred interest and fees, undisbursed portion of loan balance, unamortized costs and premiums and discounts from face amounts. Excludes loans and leases covered under loss sharing agreements.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=82891408&loc=d3e4428-111522

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