Columbia Banking System (COLB) 10-K 27 Feb 20 2019 FY Annual report Financial data

Document and Entity Information

Document and Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2019	Jan. 31, 2020	Jun. 30, 2019
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2019
Document Transition Report	false
Entity File Number	0-20288
Entity Registrant Name	COLUMBIA BANKING SYSTEM, INC.
Entity Incorporation, State or Country Code	WA
Entity Tax Identification Number	91-1422237
Entity Address, Address Line One	1301 A Street
Entity Address, City or Town	Tacoma
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	98402-2156
City Area Code	253
Local Phone Number	305-1900
Title of 12(b) Security	Common Stock, No Par Value
Trading Symbol	COLB
Security Exchange Name	NASDAQ
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Public Float			$ 2,622,530,600
Entity Common Stock, Shares Outstanding		72,146,350
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	FY
Entity Central Index Key	0000887343
Current Fiscal Year End Date	--12-31
Amendment Flag	false

Consolidated Balance Sheets

Consolidated Balance Sheets - USD ($) shares in Thousands, $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
ASSETS
Cash and due from banks	$ 223,541	$ 260,180
Interest-earning deposits with banks	24,132	17,407
Total cash and cash equivalents	247,673	277,587
Debt Securities, Available-for-sale	3,746,142	3,167,448
Federal Home Loan Bank stock at cost	48,120	25,960
Loans held for sale	17,718	3,849
Loans, net of unearned income	8,743,465	8,391,511
Loans and Leases Receivable, Allowance	83,968	83,369
Loans, net	8,659,497	8,308,142
Interest receivable	46,839	45,323
Premises and equipment, net	165,408	168,788
Other real estate owned	552	6,019
Goodwill	765,842	765,842
Other intangible assets, net	35,458	45,937
Other assets	346,275	280,250
Total Assets	14,079,524	13,095,145
LIABILITIES AND SHAREHOLDERS' EQUITY
Noninterest-bearing	5,328,146	5,227,216
Interest-bearing	5,356,562	5,230,910
Total deposits	10,684,708	10,458,126
Federal Home Loan Bank advances	953,469	399,523
Securities sold under agreements to repurchase	64,437	61,094
Subordinated Debt	35,277	35,462
Other liabilities	181,671	107,291
Total liabilities	$ 11,919,562	$ 11,061,496
Shareholders' equity:
Preferred Stock, Shares Authorized	2,000	2,000
Common stock Authorized shares	115,000	115,000
Common Stock Shares Issued	73,577	73,249
Common Stock (no par value)	$ 1,650,753	$ 1,642,246
Common Stock Shares Outstanding	72,124	73,249
Retained earnings	$ 519,676	$ 426,708
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 40,367	$ (35,305)
Treasury Stock, Shares	1,453	0
Treasury Stock, Value	$ (50,834)	$ 0
Total shareholders' equity	2,159,962	2,033,649
Total Liabilities and Shareholders' Equity	$ 14,079,524	$ 13,095,145

Consolidated Balance Sheets (Pa

Consolidated Balance Sheets (Parenthetical) - $ / shares $ / shares in Thousands	Dec. 31, 2019	Dec. 31, 2018
Common stock, par value	$ 0	$ 0
Preferred Stock, No Par Value	$ 0	$ 0

Consolidated Statements of Inco

Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Interest Income
Loans		$ 448,041		$ 428,197		$ 324,229
Taxable securities		69,864		55,969		38,659
Tax-exempt securities		10,735		12,201		11,045
Deposits in banks		1,312		702		813
Total interest income		529,952		497,069		374,746
Interest Expense
Deposits		22,146		12,105		4,800
FHLB advances		11,861		3,750		1,078
Subordinated debentures		1,871		1,871		304
Other borrowings		669		504		575
Total interest expense		36,547		18,230		6,757
Net Interest Income		493,405		478,839		367,989
Provision for loan and lease losses		3,493		14,769		8,631
Net interest income after provision for loan and lease losses		489,912		464,070		359,358
Noninterest Income
Deposit account and treasury management fees		35,695		36,072		30,381
Card revenue		15,198		19,719		25,627
Financial services and trust revenue		12,799		12,135		11,478
Loan revenue		13,465		11,866		12,399
Merchant processing revenue		0		0		4,283
Bank owned life insurance		6,294		6,007		5,380
Investment securities gains (losses), net		2,132		(89)		(11)
Gain on sale of merchant card services portfolio		0		0		14,000
Change in FDIC loss sharing asset		0		0		(447)
Other		11,598		2,546		6,552
Total noninterest income		97,181		88,256		109,642
Noninterest Expense
Compensation and employee benefits		212,867		200,199		169,674
Occupancy		35,176		36,576		32,407
Data processing		19,164		20,235		18,205
Legal and professional fees		21,645		18,044		15,151
Amortization of intangibles		10,479		12,236		6,333
Business and Occupation taxes	[1]	5,846		5,664		4,326
Advertising and promotion		4,925		5,584		4,466
Regulatory premiums		1,920		3,710		3,183
Merchant processing		0		0		2,196
Net cost (benefit) of operation of OREO		(692)		1,218		468
Other	[1]	34,152		37,024		34,608
Total noninterest expense		345,482		340,490		291,017
Income before income taxes		241,611		211,836		177,983
Income tax provision		47,160		38,954		65,155
Net Income		$ 194,451		$ 172,882		$ 112,828
Per Common Share
Basic earnings per common share		$ 2.68	[2]	$ 2.36	[2]	$ 1.86
Diluted earnings per common share		$ 2.68	[2]	$ 2.36	[2]	$ 1.86
Weighted average number of common shares outstanding		71,999		72,385		59,882
Weighted average number of diluted common shares outstanding		72,032		72,390		59,888
[1]	Beginning January 1, 2019, B&O taxes are reported separately from other taxes, licenses and fees, which are now reported under “other noninterest expense.” Prior periods have been reclassified to conform to current period presentation.
[2]	Due to averaging of shares, quarterly EPS may not add up to the totals reported for the full year.

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income	$ 194,451	$ 172,882	$ 112,828
Unrealized gain (loss) from securities:
Net unrealized holding gain (loss) from available for sale debt securities arising during the period, net of tax of ($20,540), $4,067 and $1,932	67,802	(13,425)	(3,391)
Reclassification adjustment of net gain (loss) from available for sale debt securities arising during the period, net of tax of $496, $25 and ($4)	(1,636)	(81)	7
Net unrealized gain (loss) from available for sale debt securities, net of reclassification adjustment	66,166	(13,506)	(3,384)
Pension plan liability adjustment:
Unrecognized net actuarial gain (loss) and plan amendments during the period, net of tax of $619, ($7) and ($2,287)	(2,042)	24	4,017
Less: amortization of unrecognized net actuarial losses included in net periodic pension cost, net of tax of ($74), ($74) and ($127)	(245)	(245)	(223)
Pension plan liability adjustment, net	1,797	(269)	(4,240)
Unrealized gain from cash flow hedging instruments:
Net unrealized gain in cash flow hedging instruments arising during the period, net of tax of ($3,562), $0 and $0	11,760	0	0
Reclassification adjustment for net gain (loss) in cash flow hedging instruments included in income, net of tax of $138, $0 and $0	(457)	0	0
Net unrealized gain from cash flow hedging instruments, net of reclassification adjustment	11,303	0	0
Other comprehensive income (loss)	75,672	(13,237)	856
Total comprehensive income	$ 270,123	$ 159,645	$ 113,684

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net unrealized holding gain (loss) from available for sale securities arising during the period, tax	$ (20,540)	$ 4,067	$ 1,932
Reclassification adjustment of net gain (loss) from sale of available for sale securities included in income, tax	496	25	(4)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax	619	(7)	(2,287)
Less: amortization of unrecognized net actuarial loss included in net periodic pension cost, tax	(74)	(74)	(127)
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), before Reclassification, Tax	(3,562)	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, Tax	$ 138	$ 0	$ 0

Consolidated Statements of Chan

Consolidated Statements of Changes in Shareholders' Equity - USD ($) $ in Thousands	Total	Preferred Stock [Member]	Common Stock [Member]	Treasury Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income [Member]
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-09 [Member]	$ 67		$ 184		$ (117)
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2018-02 [Member]	0				4,082	$ (4,082)
Balance, value at Dec. 31, 2016	1,251,012	$ 2,217	$ 995,837		271,957	(18,999)
Balance (in shares) at Dec. 31, 2016		9,000	58,042,000
Net income	112,828				112,828
Other comprehensive income	856					856
Issuance of common stock - acquisition related, shares		0	14,642,000
Issuance of common stock - acquisition related, value	636,385	$ 0	$ 636,385
Issuance of common stock - stock option and other plans, shares			49,000
Issuance of common stock - stock option and other plans, value	1,980		$ 1,980
Issuance of common stock - restricted stock awards, net of canceled awards, shares			241,000
Issuance of common stock - restricted stock awards, net of canceled awards, value	7,745		$ 7,745
Preferred stock conversion to common stock, shares		(9,000)
Preferred stock conversion to common stock, value		$ (2,217)
Preferred stock conversion to common stock, shares Issued			102,000
Preferred stock conversion to common stock, value Issued	0		$ 2,217
Activity in deferred compensation	1
Purchase and retirement of common stock, shares			(56,000)
Purchase and retirement of common stock, value	(2,299)		$ (2,299)
Cash settlement of acquired equity awards, value	(7,345)		(7,345)
Cash dividends declared on common stock	(51,308)				(51,308)
Balance, value at Dec. 31, 2017	$ 1,949,922	$ 0	$ 1,634,705		337,442	(22,225)
Balance (in shares) at Dec. 31, 2017		0	73,020,000
Common Stock, Dividends, Per Share, paid	$ 0.88
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2018-02 [Member]						(4,082)
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-01 [Member]	$ 0				(157)	157
Net income	172,882				172,882
Other comprehensive income	(13,237)					(13,237)
Issuance of common stock - stock option and other plans, shares			46,000
Issuance of common stock - stock option and other plans, value	1,857		$ 1,857
Issuance of common stock - restricted stock awards, net of canceled awards, shares			246,000
Issuance of common stock - restricted stock awards, net of canceled awards, value	8,354		$ 8,354
Activity in deferred compensation	7		$ 7
Purchase and retirement of common stock, shares			(63,000)
Purchase and retirement of common stock, value	(2,677)		$ (2,677)
Cash dividends declared on common stock	(83,459)				(83,459)
Balance, value at Dec. 31, 2018	$ 2,033,649	$ 0	$ 1,642,246		426,708	(35,305)
Balance (in shares) at Dec. 31, 2018		0	73,249,000
Common Stock, Dividends, Per Share, paid	$ 1.14
Cumulative Effect of New Accounting Principle in Period of Adoption | Accounting Standards Update 2016-02 [Member]	$ 782				782	0
Net income	194,451				194,451
Other comprehensive income	$ 75,672					75,672
Issuance of common stock - stock option and other plans, shares	4,327		59,000
Issuance of common stock - stock option and other plans, value	$ 2,025		$ 2,025
Issuance of common stock - restricted stock awards, net of canceled awards, shares			343,000
Issuance of common stock - restricted stock awards, net of canceled awards, value	9,271		$ 9,271
Activity in deferred compensation	3		$ 3
Purchase and retirement of common stock, shares			(74,000)
Purchase and retirement of common stock, value	(2,792)		$ (2,792)
Cash dividends declared on common stock	$ (102,265)				(102,265)
Purchase of treasury stock, shares	1,500,000		1,453,000
Purchase of treasury stock, value	$ (50,834)			$ (50,834)
Balance, value at Dec. 31, 2019	$ 2,159,962	$ 0	$ 1,650,753	$ (50,834)	$ 519,676	$ 40,367
Balance (in shares) at Dec. 31, 2019		0	72,124,000
Common Stock, Dividends, Per Share, paid	$ 1.40

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash Flows From Operating Activities
Net income	$ 194,451	$ 172,882	$ 112,828
Adjustments to reconcile net income to net cash provided by operating activities:
Provision for loan and lease losses	3,493	14,769	8,631
Stock-based compensation expense	9,271	8,354	7,745
Depreciation, amortization and accretion	34,213	32,971	31,101
Investment securities loss (gain), net	(2,132)	89	11
Net realized loss (gain) on sale of premises and equipment and loans held for investment	(7,317)	316	(139)
Net loss (gain) on sale and valuation adjustments of OREO	602	(1,218)	(495)
Gain on sale of merchant card services portfolio	0	0	(14,000)
Gain on bank owned life insurance death benefit	(3,051)	0	(4,193)
Termination of FDIC loss share agreements charge	0	0	2,409
Originations of loans held for sale	(210,484)	(133,945)	(133,460)
Proceeds from sale of loans held-for-sale	196,615	135,862	133,540
Deferred income tax expense	330	108	22,431
Net change in:
Interest receivable	(1,516)	(4,442)	(2,980)
Interest payable	632	164	131
Other assets	(23,464)	2,176	(25,471)
Other liabilities	14,308	6,679	(10,554)
Net cash provided by operating activities	204,747	237,201	128,525
Cash Flows From Investing Activities
Loans originated, net of principal collected	(291,857)	2,069	(273,927)
Purchases of securities available for sale	(1,196,895)	(965,585)	(355,607)
Purchases of loans held-for-investment	(57,075)	(46,969)	0
Purchases of premises and equipment	(8,447)	(11,328)	(6,495)
Purchases of Federal Home Loan Bank stock	(273,800)	(197,440)	(92,040)
Proceeds from FDIC for reimbursement on loss-sharing asset	0	0	26
Proceeds from sales of debt securities available for sale	259,554	32,330	30,403
Proceeds from sale of equity securities	0	4,808	0
Proceeds from principal repayments and maturities of securities available for sale	428,025	465,747	283,874
Proceeds from sales of premises and equipment and loans held for investment	8,634	16,030	12,422
Proceeds from sale of merchant card services portfolio	0	0	14,000
Proceeds from redemption of Federal Home Loan Bank Stock	251,640	181,920	98,924
Proceeds from sales of other real estate and other personal property owned	6,506	7,261	2,590
Proceeds from bank owned life insurance death benefit	8,265	5,074	10,745
Payment to FDIC to terminate loss-sharing agreements	0	0	(4,666)
Payments to FDIC related to loss-sharing asset	0	0	(210)
Net cash received in business combinations	0	0	80,472
Net cash used in investing activities	(865,450)	(506,083)	(199,489)
Cash Flows From Financing Activities
Net increase (decrease) in deposits	226,958	(73,591)	353,797
Net increase (decrease) in sweep repurchase agreements	3,343	7,035	(3,380)
Proceeds from exercise of stock options	2,025	1,857	1,980
Proceeds from Federal Home Loan Bank advances	6,845,000	4,936,000	2,301,000
Proceeds from Federal Reserve Bank borrowings	36,000	5,010	10
Proceeds from other borrowings	100	0	0
Payments for Federal Home Loan Bank advances	(6,291,000)	(4,548,000)	(2,397,000)
Payments for Federal Reserve Bank borrowings	(36,000)	(5,010)	(10)
Payments for other debt	(100)	0	0
Payments for common stock dividends	(101,911)	(83,440)	(51,308)
Repayment of junior subordinated debentures	0	8,248	6,186
Repayment of term repurchase agreement	0	(25,000)	0
Payments for cash settlement of acquired equity awards	0	0	(7,345)
Payments for purchase of treasury stock	(50,834)	0	0
Payments for purchase and retirement of common stock	2,792	2,677	2,299
Net cash provided by financing activities	630,789	203,936	189,259
Increase (decrease) in cash and cash equivalents	(29,914)	(64,946)	118,295
Cash and cash equivalents at beginning of period	277,587	342,533	224,238
Supplemental Information:
Cash paid for interest	35,916	18,066	6,626
Cash paid for income tax, net of refunds	47,375	24,067	59,071
Non-cash investing and financing activities:
Loans transferred to OREO	386	1,200	106
Share-based consideration issued in business combinations	0	0	636,385
Premises and equipment expenditures incurred but not yet paid	451	195	0
Change in dividends payable on unvested shares included in other liabilities	$ 354	$ 19	$ 0

Summary of Significant Accounti

Summary of Significant Accounting Policies	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	Summary of Significant Accounting Policies and Reclassifications Organization Columbia Banking System, Inc. (the “Corporation,” “we,” “our,” “Columbia” or the “Company”) is the holding company for Columbia State Bank (“Columbia Bank” or the “Bank”) and Columbia Trust Company (“Columbia Trust”). The Bank provides a full range of financial services through 146 branch locations, including 71 in the State of Washington, 61 in Oregon and 14 in Idaho. Columbia Trust provides fiduciary, agency, trust and related services, and life insurance products. Because the Bank comprises substantially all of the business of the Corporation, references to the “Company” mean the Corporation, the Bank and Columbia Trust together. The Corporation is approved as a bank holding company pursuant to the Gramm-Leach-Bliley Act of 1999. The Company’s accounting and reporting policies conform to GAAP and practices in the financial services industry. To prepare the financial statements in conformity with GAAP, management must make estimates and assumptions that affect the reported amounts of assets and liabilities at the date of the financial statements, and income and expenses during the reporting period. Circumstances and events that differ significantly from those underlying our estimates and assumptions could cause actual financial results to differ from our estimates. The most significant estimates included in the financial statements relate to the ALLL, business combinations and goodwill impairment. The Company has applied its accounting policies and estimation methods consistently in all periods presented in these financial statements (to the periods in which they applied), with the exception of our lease accounting under ASC 842, which was adopted prospectively, beginning in 2019. Consolidation The Consolidated Financial Statements of the Company include the accounts of the Corporation and its subsidiaries, including the Bank and Columbia Trust. Intercompany balances and transactions have been eliminated in consolidation. Cash and cash equivalents Cash and cash equivalents include cash and due from banks, and interest-bearing balances due from correspondent banks and the FRB. Cash equivalents have a maturity of 90 days or less at the time of purchase. Securities Securities are classified based on management’s intention on the date of purchase. All securities are classified as available for sale and are presented at fair value. Unrealized gains or losses on securities available for sale are excluded from net income but are included as separate components of other comprehensive income, net of taxes. Purchase premiums or discounts on securities available for sale are amortized or accreted into income using the interest method over the terms of the individual securities. The Company performs a quarterly assessment to determine whether a decline in fair value below amortized cost is other-than-temporary. Amortized cost includes adjustments made to the cost of an investment for accretion, amortization, collection of cash and previous other-than-temporary impairment recognized in earnings. Other-than-temporary impairment exists when it is more likely than not that the Company will be unable to recover the entire amortized cost basis of the security. In performing the quarterly assessment for debt securities, management considers whether or not the Company expects to recover the entire amortized cost basis of the security. In addition, management also considers whether it is more likely than not that it will not have to sell the security before recovery of its cost basis. If the Company intends to sell a security or it is more likely than not it will be required to sell a security prior to recovery of its cost basis, the entire amount of impairment is recognized in earnings. If the Company does not intend to sell the security or it is not more likely than not it will be required to sell the security prior to recovery of its cost basis, the credit loss component of impairment is recognized in earnings and impairment associated with non-credit factors, such as market liquidity, is recognized in “Other comprehensive income (loss), net of tax.” A credit loss is the difference between the cost basis of the security and the present value of cash flows expected to be collected, discounted at the security’s effective interest rate at the date of acquisition. The cost basis of an other-than-temporarily impaired security is written down by the amount of impairment recognized in earnings. The new cost basis is not adjusted for subsequent recoveries in fair value. However, the difference between the new amortized cost basis and the cash flows expected to be collected is accreted as interest income. The total other-than-temporary impairment, if any, is presented in the Consolidated Statements of Income with a reduction for the amount of other-than-temporary impairment that is recognized in “Other Comprehensive Income,” if any. Realized gains or losses on sales of securities available for sale are recorded using the specific identification method. Federal Home Loan Bank Stock The Company holds shares of Class B stock issued by the FHLB, which has been designated as FHLB membership stock or FHLB activity based stock in accordance with the capital plan of the FHLB. Membership stock is stock we are required to purchase and hold as a condition of membership in the FHLB. The Company’s membership stock purchase requirement is measured as a percentage of our year end assets, subject to a $10 million cap. Class B stock may be redeemed, subject to certain limitations, on five years’ written notice to the FHLB. Activity based stock is stock we are required to purchase and hold in order to obtain an advance or participate in FHLB mortgage programs. The Company’s activity based stock purchase requirement is measured as a percentage of our advance proceeds. Our FHLB stock is carried at par value because the shares are issued, transferred, redeemed, and repurchased by the FHLB at a par value of $100 . The FHLB stock is subject to recoverability testing per the Financial Services-Depository and Lending topic of the FASB ASC. Loans held for sale Mortgage loans held for sale are carried at the lower of amortized cost or fair value. Due to the short period of time between the origination and sale, the carrying amount of loans held for sale approximates the fair values. Loans Loans, excluding PCI loans, are generally carried at the unpaid principal balance, net of purchase premiums, purchase discounts and net deferred loan fees. Net deferred loan fees include nonrefundable loan origination fees less direct loan origination costs. Net deferred loan fees, purchase premiums and purchase discounts are amortized into interest income using either the interest method or straight-line method over the terms of the loans, adjusted for actual prepayments. The interest method is used for all loans except revolving loans, for which the straight-line method is used. Interest income is accrued as earned. Fees related to lending activities, other than the origination or purchase of loans, are recognized as noninterest income during the period the related services are performed. Nonaccrual loans —Loans are placed on nonaccrual status when a loan becomes contractually past due 90 days with respect to interest or principal unless the loan is both well secured and in the process of collection, or if full collection of interest or principal becomes uncertain. When a loan is placed on nonaccrual status, any accrued and unpaid interest receivable is reversed and the amortization of net deferred loan fees, premiums and discounts ceases. The interest payments received on nonaccrual loans are generally accounted for on the cost-recovery method whereby the interest payment is applied to the principal balances. Loans may be returned to accrual status when improvements in credit quality eliminate the doubt as to the full collectability of both interest and principal and a period of sustained performance has occurred. Impaired loans —Loans are considered impaired when based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a TDR. The assessment for impairment occurs when and while such loans are designated as classified per the Company’s internal risk rating system or when and while such loans are on nonaccrual. All nonaccrual loans greater than $500,000 and all TDR loans are considered impaired and analyzed individually on a quarterly basis. Classified loans with an outstanding balance greater than $500,000 are evaluated for potential impairment on a quarterly basis. Restructured Loans —A loan is classified as a TDR when a borrower is experiencing financial difficulties that lead to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include interest rate reductions, principal forgiveness, extension of maturity date and other actions intended to minimize potential losses. Generally, a nonaccrual loan that is restructured remains on nonaccrual status for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower’s performance under the new terms is not reasonably assured, the loan remains classified as a nonaccrual loan. Purchased Credit Impaired Loans —Loans acquired with evidence of credit deterioration since origination for which it is probable that all contractually required payments will not be collected are accounted for under ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality . In addition, because of the significant discounts associated with certain of the acquired loan portfolios, the Company elected to account for those certain acquired loans under ASC 310-30. In situations where such loans have similar risk characteristics, loans are aggregated into pools to estimate cash flows. A pool is accounted for as a single asset with a single interest rate, cumulative loss rate and cash flow expectation. Expected cash flows at the acquisition date in excess of the fair value of loans are considered to be accretable yield, which is recognized as interest income over the life of the loan pool using a level yield method if the timing and amount of the future cash flows of the pool is reasonably estimable. Subsequent to the acquisition date, any increases in cash flow over those expected at purchase date in excess of fair value are recorded as interest income prospectively. Any subsequent decreases in cash flow over those expected at purchase date due to credit deterioration are recognized by recording an ALLL on PCI loans. Any disposals of loans, including sales of loans, payments in full or foreclosures result in the removal of the loan from the loan pool at the carrying amount. Unfunded loan commitments —Unfunded commitments are generally related to providing credit facilities to clients of the Bank and are not actively traded financial instruments. These unfunded commitments are disclosed as financial instruments with off-balance sheet risk in Note 18, “Commitments and Contingent Liabilities.” Allowance for Loan and Lease Losses The ALLL is an accounting estimate of incurred credit losses in our loan portfolio at the balance sheet date. The provision for loan and lease losses is the expense recognized in the Consolidated Statements of Income to adjust the allowance to the levels deemed appropriate by management, as measured by the Company’s credit loss estimation methodologies. Loans Collectively Evaluated for Impairment —This measure of estimated credit losses is based upon the loss experience over a historical base period adjusted for a loss emergence period. The loss emergence period is an estimate of the period that it takes, on average, for us to identify the amount of loss incurred for a loan that has suffered a loss-causing event. Management then considers the effects of the following qualitative factors to ensure our allowance reflects the inherent losses in the loan portfolio: • Economic and business conditions; • Concentration of credit; • Lending management and staff; • Lending policies and procedures; • Loss and recovery trends; • Nature and volume of the portfolio; • Trends in problem loans, loan delinquencies and nonaccrual loans; • Quality of internal loan review; and • External factors. These qualitative factors have a high degree of subjectivity and changes in any of the factors could have a significant impact on our calculation of the allowance. The qualitative adjustment by loan segment is based upon management's assessment of inherent losses within a range between the weighted historical loss factor by segment and the maximum consecutive quarterly losses in the relevant loss emergence period by segment over the historical base period. Loan and lease losses are charged against the allowance when management believes the collectability of a loan balance is unlikely. Subsequent recoveries, if any, are credited to the allowance. Loans Individually Evaluated for Impairment —This measure of estimated credit losses begins if, based upon current information and events, we believe it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a TDR. When a loan has been identified as impaired, the amount of impairment will be measured using discounted cash flows, except when it is determined that the remaining source of repayment for the loan is the operation or liquidation of the underlying collateral. In these cases, the current fair value of the collateral, reduced by costs to sell, will be used in place of discounted cash flows. As a final alternative, the observable market price of the loan may be used to assess impairment. The Company predominately uses the fair value of collateral approach based upon a reliable valuation. When the measurement of the impaired loan is less than the recorded amount of the loan, an impairment is recognized by recording a charge-off to the allowance or by designating a specific reserve. Purchased Credit Impaired Loans —The Company updates its cash flow projections for PCI loans accounted for under ASC 310-30 on a quarterly basis. Assumptions utilized in this process include projections related to probability of default, loss severity, prepayment and recovery lag. Projections related to probability of default and prepayment are calculated utilizing a loan migration analysis. The loan migration analysis is a matrix of probability that is used to estimate the probability of a loan pool transitioning into a particular delinquency state given its delinquency state at the re-measurement date. Loss severity factors are based upon either actual charge-off data within the loan pools or industry averages, and recovery lags are based upon the collateral within the loan pools. Any decreases in expected cash flows after the acquisition date and subsequent measurement periods are recognized by recording a provision for loan losses. See “Purchased Credit Impaired Loans” under “Loans” for further discussion. Unfunded Commitments and Letters of Credit —The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the allowance is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The allowance for unfunded commitments is included in “Other liabilities” on the Consolidated Balance Sheets, with changes to the balance charged against noninterest expense. Adoption of Allowance for Credit Losses - ASC 326 In accordance with ASU 2016-13, the Company was required to adopt ASC 326 as of January 1, 2020. The allowance for credit losses under ASC 326 is an accounting estimate of expected losses over the contractual life of assets carried at amortized cost within the Company’s loan portfolio at the balance sheet date. The ASU requires a financial asset (or group of financial assets) measured at amortized cost to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset to present the net carrying value at the amount expected to be collected on the financial asset. The quantitative allowance is calculated using a discounted cash flow approach with a probability of default methodology. The probability of default is an assumption derived from regression models which determines the relationship between historical defaults and certain economic variables. The Company determines a reasonable and supportable forecast and applies that forecast to the model to determine defaults over the forecast period. Following the forecast period, the economic variables used to calculate the probability of default revert to a historical average. Other assumptions relevant to the discounted cash flow model to derive the quantitative allowance include the loss given default, which is the estimate of loss for a defaulted loan, and the discount rate applied to future cash flows. The model calculates the net present value of each loan using both the contractual and expected cash flows, respectively. In addition to the quantitative portion of the allowance for credit losses, the Company also considers the effects of the following qualitative factors in its calculation of expected losses in the loan portfolio: • Economic and business conditions; • Concentration of credit; • Lending management and staff; • Lending policies and procedures; • Loss and recovery trends; • Nature and volume of the portfolio; • Trends in problem loans, loan delinquencies and nonaccrual loans; • Quality of internal loan review; and • External factors. These qualitative factors are based in quantitative factors but also include a high degree of subjectivity and changes in any of the factors could have a significant impact on our calculation of the allowance. Loans for which repayment is expected to be provided substantially through the operation or sale of collateral are considered collateral-dependent. The allowance for credit losses for collateral-dependent loans is measured on the basis of the fair value of the collateral when foreclosure is probable. Premises and Equipment Land, buildings, leasehold improvements and equipment are stated at cost less accumulated depreciation and amortization. Gains or losses on dispositions are reflected in current operations. Expenditures for improvements and major renewals are capitalized, and ordinary maintenance, repairs and small purchases are charged to “Occupancy” expense in the Consolidated Statements of Income. Depreciation and amortization are computed based on the straight-line method over the estimated useful lives of the various classes of assets. The ranges of useful lives for the principal classes of assets are as follows: Buildings and building improvements 5 to 39 years Leasehold improvements Term of lease or useful life, whichever is shorter Furniture, fixtures and equipment 3 to 7 years Vehicles 5 years Computer software 3 to 5 years Software Capitalized software is stated at cost, less accumulated amortization. Amortization is computed on a straight-line basis and charged to expense over the estimated useful life of the software, which is generally three years. Capitalized software is included in “Premises and equipment, net” in the Consolidated Balance Sheets. Implementation Costs in a Cloud Computing Arrangement Implementation costs incurred in a hosting arrangement that is a service contract are capitalized based on criteria in ASC 350-40. The capitalized costs are expensed over the term of the hosting arrangement. Capitalized implementation costs in a cloud computing arrangement are included in “Other assets” in the Consolidated Balance Sheets. Other Real Estate Owned OREO is composed of real estate acquired by the Company through either foreclosure or deed in lieu of foreclosure in satisfaction of debt. At acquisition, OREO is recorded at fair value less estimated costs to sell. Any fair value adjustments at acquisition are charged to the allowance, or in the event of a write-up without previous losses charged to the allowance, a credit to earnings is recorded. The fair value of the OREO is based upon a current appraisal or a letter of intent to purchase. Losses that result from the ongoing periodic valuation of these properties are charged to the net cost of operation of OREO in the period in which they are identified. Improvements to OREO are capitalized and holding costs are charged to the net cost of operation of OREO as incurred. Goodwill and Intangibles Net assets of companies acquired in a business combination are recorded at fair value at the date of acquisition. Any excess of the purchase price over the fair value of net assets acquired, including identified intangible assets, is recognized as goodwill. Goodwill is reviewed for potential impairment annually, during the third quarter, or, more frequently, if events or circumstances indicate a potential impairment, at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment for which discrete financial information is available and regularly reviewed by management. The Company consists of a single reporting unit. If the fair value of the reporting unit, including goodwill, is determined to be less than the carrying amount of the reporting unit, a further test is required to measure the amount of impairment. If an impairment loss exists, the carrying amount of goodwill is adjusted to a new cost basis. Subsequent reversal of a previously recognized goodwill impairment loss is prohibited. Identified intangible assets are amortized on an accelerated basis over the period benefited. Intangible assets are also evaluated for impairment if events and circumstances indicate a possible impairment. Such evaluation is based on undiscounted cash flow projections. At December 31, 2019 , intangible assets included in the Consolidated Balance Sheets principally consisted of CDI with an original estimated life of 10 years . Leases The Company determines if a lease is present at the inception of an agreement. Operating leases are capitalized at commencement and are discounted using the Company’s FHLB borrowing rate for a similar term borrowing unless the lease defines an implicit rate within the contract. Leases with original terms of less than 12 months are not capitalized. For operating leases existing prior to January 1, 2019, the rate for the remaining lease term as of January 1, 2019 was used. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease right-of-use assets and operating lease liabilities are recognized on the lease commencement date based on the present value of lease payments over the lease term. The lease term includes options to extend or terminate the lease if the Company is reasonably certain that an option will be exercised. Operating leases are included within “Other assets” in the Consolidated Balance Sheets. See Note 10, “Leases” for additional information on leases. Income Taxes The provision for income taxes includes current and deferred income tax expense on net income adjusted for temporary and permanent differences such as interest income from state and municipal securities and investments in affordable housing tax credits. Deferred tax assets and liabilities are recognized for the expected future tax consequences of existing temporary differences between the financial reporting and tax reporting basis of assets and liabilities using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. On a quarterly basis, management evaluates deferred tax assets to determine if these tax benefits are expected to be realized in future periods. This determination is based on facts and circumstances, including the Company’s current and future tax outlook. To the extent a deferred tax asset is no longer considered “more likely than not” to be realized, a valuation allowance is established. We recognize the tax benefit from uncertain tax positions only if it is more likely than not that the tax positions will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax benefit is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. We recognize interest and penalties related to unrecognized tax benefits in “Provision for income taxes” in the Consolidated Statements of Income. Advertising Advertising costs are generally expensed as incurred. Earnings per Common Share The Company’s capital structure includes common shares, restricted common share awards, common share options, and, during a portion of 2017, convertible preferred shares. Restricted common share awards participate in dividends declared on common shares at the same rate as common shares. Convertible preferred shares participated in dividends declared on common shares on an “as if converted” basis. Restricted common share awards and convertible preferred shares are considered participating securities under the EPS topic of the FASB ASC. The Company calculates EPS using the two-class method. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common shareholders but does not require the presentation of basic and diluted EPS for securities other than common shares. Under the two-class method, basic EPS is computed by dividing earnings allocated to common shareholders by the weighted average number of common shares outstanding for the period. Earnings allocated to common shareholders represents net income reduced by earnings allocated to participating securities. Diluted EPS is computed in the same manner as basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding if certain shares issuable upon exercise of common share options were included unless those additional shares would have been anti-dilutive. For the diluted EPS computation, the treasury stock method is applied and compared to the two-class method and whichever method results in a more dilutive impact is utilized to calculate diluted EPS. Share-Based Payment The Company accounts for stock options and stock awards in accordance with the Compensation—Stock Compensation topic of the FASB ASC. Authoritative guidance requires the Company to measure the cost of employee services received in exchange for an award of equity instruments, such as stock options or stock awards, based on the fair value of the award on the grant date. This cost must be recognized in the Consolidated Statements of Income over the vesting period of the award. The Company issues restricted common share awards which generally vest over a four-year period and have full voting rights. Pursuant to our new equity incentive plan approved in 2018, for any awards issued under the new plan, the holder accrues dividends, which are paid out when the shares vest. For any awards granted prior to the new plan, the holder receives dividends whether or not the shares have vested. Restricted stock is valued at the closing price of the Company’s stock on the date of an award. Derivatives and Hedging Activities In accordance with the Derivatives and Hedging topic of the FASB ASC, the Company recognizes derivatives as assets or liabilities on the Consolidated Balance Sheets at their fair value. The Company periodically enters into interest rate contracts with customers and offsetting contracts with third parties. As these interest rate contracts are not designated as hedges under the Derivatives and Hedging topic of the FASB ASC, the changes in fair value of these instruments are recognized immediately in earnings. As part of the Company’s overall interest rate risk management, the Company uses an interest rate collar with a notional amount of $500.0 million to mitigate interest rate risk. This collar is designated and qualifies as a cash flow hedge. Gains and losses are recorded in accumulated other comprehensive income to the extent the hedge is effective. Gains and losses are reclassified from accumulated other comprehensive income to earnings in the period the hedged transaction affects earnings and are included in the same income statement line item that the hedged transaction is recorded. Accounting Pronouncements Recently Adopted or Issued Accounting Standards Adopted in 2019 In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) . The amendments included in this ASU create a new accounting model for both lessees and lessors. The new guidance requires lessees to recognize lease liabilities, initially measured at the present value of future lease payments, and corresponding right-of-use assets for all leases with lease terms greater than 12 months. The new lease model differs from the old lease accounting model, as the old model does not require such lease liabilities and corresponding right-of-use assets to be recorded for operating leases. The amendments in ASU 2016-02 must be adopted using the modified retrospective approach and will be effective for the first interim or annual period beginning after December 15, 2018. The FASB subsequently issued ASU 2018-11, which allows for an additional (optional) transition method. The Company adopted the new standard effective January 1, 2019 utilizing the transition method allowed under ASU 2018-11 and did not restate comparative periods. The Company elected the package of practical expedients permitted under the transition guidance, which allowed us to carryforward our historical lease classifications and our assessment on whether a contract is or contains a lease. We also elected to keep leases with an initial term of 12 months or less off the balance sheet. The adoption of the new standard resulted in an increase in other assets and an increase in other liabilities of $49.2 million and $48.2 million , respectively. The Company recognized a cumulative effect adjustment of $782 thousand to increase the beginning balance of retained earnings related to previous deferred gains on sale-leaseback transactions. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract . The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The amendments also require the entity to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement, including reasonably certain renewal periods. The amendments in ASU 2018-15 are effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. The amendments can be adopted on a prospective or retrospective basis. The Company adopted the new standard effective July 1, 2019 on a prospective basis. The adoption of the new standard resulted in an increase in other assets of $1.5 million . Recently Issued Accounting Standards, Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes. The guidance issued in this update simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in ASC 740 related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim perio

Business Combinations

Business Combinations	12 Months Ended
	Dec. 31, 2019
Business Acquisition [Line Items]
Business Combination Disclosure [Text Block]	Business Combinations Pacific Continental On November 1, 2017 , the Company completed its acquisition of Pacific Continental and its wholly-owned banking subsidiary Pacific Continental Bank. The Company acquired 100% of the equity interests of Pacific Continental. The primary reasons for the acquisition were to expand in the Eugene, Oregon market and improve branch network efficiencies in the Seattle and Portland markets. The assets acquired and liabilities assumed have been accounted for under the acquisition method of accounting. The assets and liabilities, both tangible and intangible, were recorded at their fair values as of the November 1, 2017 acquisition date. The application of the acquisition method of accounting resulted in the recognition of goodwill of $383.1 million and a CDI of $46.9 million . The goodwill represents the excess of the purchase price over the fair value of the net assets acquired. The goodwill is not deductible for income tax purposes. The table below summarizes the amounts recognized as of the acquisition date for each major class of assets acquired and liabilities assumed: November 1, 2017 (in thousands) Merger consideration $ 637,103 Identifiable net assets acquired, at fair value Assets acquired Cash and cash equivalents $ 81,190 Investment securities 449,291 FHLB stock 7,084 Loans 1,873,987 Interest receivable 7,827 Premises and equipment 27,343 OREO 10,279 CDI 46,875 Other assets 50,638 Total assets acquired 2,554,514 Liabilities assumed Deposits (2,118,982 ) FHLB advances (101,127 ) Subordinated debentures (35,678 ) Junior subordinated debentures (14,434 ) Securities sold under agreements to repurchase (1,617 ) Other liabilities (28,653 ) Total liabilities assumed (2,300,491 ) Total fair value of identifiable net assets 254,023 Goodwill $ 383,080 See Note 9, “Goodwill and Other Intangible Assets,” for further discussion of the accounting for goodwill and other intangible assets. The operating results of the Company reported herein include the operating results produced by the acquired assets and assumed liabilities for the period November 1, 2017 to December 31, 2019 . Disclosure of the amount of Pacific Continental’s revenue and net income (excluding integration costs) included in Columbia’s Consolidated Statements of Income is impracticable due to the integration of the operations and accounting for this acquisition. For illustrative purposes only, the following table presents certain unaudited pro forma information for the year ended December 31, 2017 . This unaudited, estimated pro forma financial information was calculated as if Pacific Continental had been acquired as of the beginning of the year prior to the date of acquisition. This unaudited pro forma information combines the historical results of Pacific Continental with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition occurred as of the beginning of the year prior to the acquisition. In particular, no adjustments have been made to eliminate the impact of other-than-temporary impairment losses and losses recognized on the sale of securities that may not have been necessary had the investment securities been recorded at fair value as of the beginning of the year prior to the date of acquisition. The unaudited pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value. Additionally, Columbia expects to achieve further operating cost savings and other business synergies, including revenue growth as a result of the acquisition, which are not reflected in the pro forma amounts that follow. As a result, actual amounts would have differed from the unaudited pro forma information presented. Unaudited Pro Forma for the Year Ended December 31, 2017 (in thousands, except per share amounts) Total revenues (net interest income plus noninterest income) $ 571,944 Net income $ 149,859 EPS - basic $ 2.23 EPS - diluted $ 2.23 The following table shows the impact of the acquisition-related expenses related to the acquisition of Pacific Continental for the periods indicated to the various components of noninterest expense: Years ended December 31, 2019 2018 2017 (in thousands) Noninterest Expense Compensation and employee benefits $ — $ 3,620 $ 8,014 Occupancy — 1,619 1,912 Data processing — 963 1,555 Legal and professional fees — 1,028 4,618 Advertising and promotion — 537 467 Other — 894 630 Total impact of acquisition-related costs to noninterest expense $ — $ 8,661 $ 17,196

Cash and Cash Equivalents

Cash and Cash Equivalents	12 Months Ended
	Dec. 31, 2019
Cash and Cash Equivalents [Abstract]
Cash and Cash Equivalents	Cash and Cash Equivalents The Company is required to maintain an average reserve balance with the FRB or maintain such reserve balance in the form of cash. The average required reserve balance for the years ended December 31, 2019 and 2018 was approximately $84.9 million and $110.2 million , respectively, and was met by holding cash and maintaining an average balance with the FRB.

Securities

Securities	12 Months Ended
	Dec. 31, 2019
Debt Securities, Available-for-sale [Abstract]
Securities	Securities At December 31, 2019 , the Company’s securities portfolio primarily consisted of securities issued by the U.S. government, U.S. government agencies, U.S. government-sponsored enterprises and state and municipalities. All of the Company’s mortgage-backed securities and collateralized mortgage obligations are issued by U.S. government agencies and U.S. government-sponsored enterprises and are implicitly guaranteed by the U.S. government. The Company had no other issuances in its portfolio which exceeded ten percent of shareholders’ equity. The following table summarizes the amortized cost, gross unrealized gains and losses and the resulting fair value of debt securities available for sale: Amortized Gross Gross Fair Value December 31, 2019 (in thousands) U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,864,949 $ 47,223 $ (19,222 ) $ 2,892,950 Other asset-backed securities (1) 194,563 2,476 (989 ) 196,050 State and municipal securities 478,366 10,660 (224 ) 488,802 U.S. government agency and government-sponsored enterprise securities 165,218 3,127 (5 ) 168,340 Total $ 3,703,096 $ 63,486 $ (20,440 ) $ 3,746,142 December 31, 2018 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,045,728 $ 8,473 $ (40,846 ) $ 2,013,355 Other asset-backed securities (1) 176,793 763 (2,621 ) 174,935 State and municipal securities 579,755 2,328 (7,760 ) 574,323 U.S. government agency and government-sponsored enterprise securities 408,088 1,235 (4,736 ) 404,587 U.S. government securities 251 — (3 ) 248 Total $ 3,210,615 $ 12,799 $ (55,966 ) $ 3,167,448 __________ (1) Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation. The following table provides the proceeds and both gross realized gains and losses on the sales and calls of debt securities available for sale as well as other securities gains and losses for the periods indicated: Years Ended December 31, 2019 2018 2017 (in thousands) Proceeds from sales and calls of debt securities available for sale $ 259,554 $ 32,330 $ 30,403 Gross realized gains from sales of debt securities available for sale $ 3,357 $ 235 $ 111 Gross realized losses from sales of debt securities available for sale (1,225 ) (129 ) (122 ) Other securities losses, net (1) — (195 ) — Investment securities gains (losses), net $ 2,132 $ (89 ) $ (11 ) __________ (1) Other securities losses, net includes net unrealized loss activity associated with equity securities. The scheduled contractual maturities of debt securities available for sale at December 31, 2019 are presented as follows: December 31, 2019 Amortized Cost Fair Value (in thousands) Due within one year $ 77,363 $ 77,538 Due after one year through five years 416,556 421,363 Due after five years through ten years 2,007,225 2,041,751 Due after ten years 1,201,952 1,205,490 Total debt securities available for sale $ 3,703,096 $ 3,746,142 The following table summarizes the carrying value of securities pledged as collateral to secure public deposits, borrowings and other purposes as permitted or required by law: December 31, 2019 2018 (in thousands) To secure public funds $ 323,055 $ 276,343 To secure borrowings 111,488 52,303 Other securities pledged 154,030 138,492 Total securities pledged as collateral $ 588,573 $ 467,138 The following tables show the gross unrealized losses and fair value of the Company’s debt securities available for sale with unrealized losses that are not deemed to be other-than-temporarily impaired, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2019 and 2018 : Less than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized December 31, 2019 (in thousands) U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 1,055,903 $ (12,424 ) $ 491,539 $ (6,798 ) $ 1,547,442 (19,222 ) Other asset-backed securities (1) 89,508 (880 ) 6,799 (109 ) 96,307 (989 ) State and municipal securities 12,363 (142 ) 12,587 (82 ) 24,950 (224 ) U.S. government agency and government-sponsored enterprise securities — — 10,495 (5 ) 10,495 (5 ) Total $ 1,157,774 $ (13,446 ) $ 521,420 $ (6,994 ) $ 1,679,194 $ (20,440 ) December 31, 2018 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 114,551 $ (750 ) $ 1,207,020 $ (40,096 ) $ 1,321,571 $ (40,846 ) Other asset-backed securities (1) 40,071 (222 ) 94,367 (2,399 ) 134,438 (2,621 ) State and municipal securities 106,292 (581 ) 280,496 (7,179 ) 386,788 (7,760 ) U.S. government agency and government-sponsored enterprise securities 15,392 (45 ) 291,435 (4,691 ) 306,827 (4,736 ) U.S. government securities — — 247 (3 ) 247 (3 ) Total $ 276,306 $ (1,598 ) $ 1,873,565 $ (54,368 ) $ 2,149,871 $ (55,966 ) __________ (1) Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation. At December 31, 2019 , there were 243 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligation securities in an unrealized loss position, of which 162 were in a continuous loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates relative to where these investments fall within the yield curve and their individual characteristics. Because the Company does not currently intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at December 31, 2019 . At December 31, 2019 , there were 18 other asset-backed securities in an unrealized loss position, of which six were in a continuous loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates relative to where these investments fall within the yield curve and their individual characteristics. Because the Company does not currently intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at December 31, 2019 . At December 31, 2019 , there were 24 state and municipal government securities in an unrealized loss position, of which 14 were in a continuous loss position for 12 months or more. The unrealized losses on state and municipal securities were caused by interest rate changes or widening of market spreads subsequent to the purchase of the individual securities. Management monitors published credit ratings of these securities for adverse changes. As of December 31, 2019 , none of the rated obligations of state and local government entities held by the Company had a below investment grade credit rating. Because the credit quality of these securities is investment grade and the Company does not currently intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at December 31, 2019 . At December 31, 2019 , there were three U.S. government agency and government-sponsored enterprise securities in an unrealized loss position, all of which were in a continuous loss position for 12 months or more. The decline in fair value is attributable to changes in interest rates relative to where these investments fall within the yield curve and their individual characteristics. Because the Company does not currently intend to sell these securities nor does the Company consider it more likely than not that it will be required to sell these securities before the recovery of amortized cost basis, which may be upon maturity, the Company does not consider these investments to be other-than-temporarily impaired at December 31, 2019 . At December 31, 2019 , there were no

Loans

Loans	12 Months Ended
	Dec. 31, 2019
Loans and Leases Receivable, Net Amount [Abstract]
Financing Receivables [Text Block]	Loans The Company’s loan portfolio includes originated and purchased loans. Originated loans and purchased loans for which there was no evidence of credit deterioration at their acquisition date and it was probable that we would be able to collect all contractually required payments are referred to collectively as loans, excluding PCI loans. Purchased loans for which there was, at acquisition date, evidence of credit deterioration since their origination and it was probable that we would be unable to collect all contractually required payments are referred to as PCI loans. The following is an analysis of the loan portfolio by segment (net of unearned income): December 31, 2019 2018 Loans, excluding PCI loans PCI Loans Total Loans, excluding PCI loans PCI Loans Total (in thousands) Commercial business $ 3,602,597 $ 7,863 $ 3,610,460 $ 3,438,422 $ 9,240 $ 3,447,662 Real estate: One-to-four family residential 265,144 7,203 272,347 238,367 8,017 246,384 Commercial and multifamily residential 4,183,961 54,212 4,238,173 3,846,027 62,910 3,908,937 Total real estate 4,449,105 61,415 4,510,520 4,084,394 70,927 4,155,321 Real estate construction: One-to-four family residential 192,762 — 192,762 217,790 153 217,943 Commercial and multifamily residential 163,103 — 163,103 284,394 534 284,928 Total real estate construction 355,865 — 355,865 502,184 687 502,871 Consumer 292,697 8,238 300,935 318,945 8,906 327,851 Less: Net unearned income (34,315 ) — (34,315 ) (42,194 ) — (42,194 ) Total loans, net of unearned income 8,665,949 77,516 8,743,465 8,301,751 89,760 8,391,511 Less: ALLL (81,124 ) (2,844 ) (83,968 ) (79,758 ) (3,611 ) (83,369 ) Total loans, net $ 8,584,825 $ 74,672 $ 8,659,497 $ 8,221,993 $ 86,149 $ 8,308,142 Loans held for sale $ 17,718 $ — $ 17,718 $ 3,849 $ — $ 3,849 At December 31, 2019 and 2018 , the Company had no material foreign activities. Substantially all of the Company’s loans and unfunded commitments are geographically concentrated in its service areas within the states of Washington, Oregon and Idaho. At December 31, 2019 and 2018 , $3.24 billion and $3.22 billion , respectively, of commercial and residential real estate loans were pledged as collateral on FHLB advances. The Company has also pledged $151.3 million and $82.0 million of commercial loans to the FRB for additional borrowing capacity at December 31, 2019 and 2018 , respectively. Nonaccrual loans totaled $33.1 million and $54.8 million at December 31, 2019 and 2018 , respectively. The amount of interest income foregone as a result of these loans being placed on nonaccrual status totaled $2.0 million for 2019 , $3.6 million for 2018 and $2.4 million for 2017 . There were no loans 90 days past due and still accruing interest as of December 31, 2019 and 2018 . At December 31, 2019 and 2018 , there were $2.0 million and $2.1 million , respectively, of commitments of additional funds for loans accounted for on a nonaccrual basis. The following is an analysis of nonaccrual loans as of December 31, 2019 and 2018 : December 31, 2019 2018 Recorded Unpaid Principal Recorded Unpaid Principal (in thousands) Commercial business: Secured $ 26,615 $ 38,278 $ 35,504 $ 45,072 Unsecured 359 360 9 9 Real estate: One-to-four family residential 591 632 1,158 1,178 Commercial and multifamily residential: Commercial land 1,985 1,994 2,261 2,270 Income property 205 206 2,721 3,062 Owner occupied 1,287 1,325 9,922 10,300 Real estate construction: One-to-four family residential: Land and acquisition — — 318 318 Residential construction — 59 — — Consumer 2,018 2,355 2,949 3,149 Total $ 33,060 $ 45,209 $ 54,842 $ 65,358 Loans, excluding PCI loans The following is an aging of the recorded investment of the loan portfolio as of December 31, 2019 and 2018 : Current 30 - 59 60 - 89 Greater Total Nonaccrual Total Loans December 31, 2019 (in thousands) Commercial business: Secured $ 3,422,313 $ 7,684 $ 5,035 $ — $ 12,719 $ 26,615 $ 3,461,647 Unsecured 128,852 392 80 — 472 359 129,683 Real estate: One-to-four family residential 261,886 2,162 256 — 2,418 591 264,895 Commercial and multifamily residential: Commercial land 300,580 625 — — 625 1,985 303,190 Income property 2,057,359 1,797 — — 1,797 205 2,059,361 Owner occupied 1,795,771 4,287 — — 4,287 1,287 1,801,345 Real estate construction: One-to-four family residential: Land and acquisition 1,364 — — — — — 1,364 Residential construction 189,350 951 — — 951 — 190,301 Commercial and multifamily residential: Income property 88,389 — — — — — 88,389 Owner occupied 73,203 — — — — — 73,203 Consumer 290,174 284 95 — 379 2,018 292,571 Total $ 8,609,241 $ 18,182 $ 5,466 $ — $ 23,648 $ 33,060 $ 8,665,949 Current 30 - 59 60 - 89 Greater Total Nonaccrual Total Loans December 31, 2018 (in thousands) Commercial business: Secured $ 3,267,709 $ 5,864 $ 3,624 $ — $ 9,488 $ 35,504 $ 3,312,701 Unsecured 111,868 240 — — 240 9 112,117 Real estate: One-to-four family residential 233,941 694 233 — 927 1,158 236,026 Commercial and multifamily residential: Commercial land 283,416 — — — — 2,261 285,677 Income property 1,910,505 5,009 2,241 — 7,250 2,721 1,920,476 Owner occupied 1,606,085 1,744 — — 1,744 9,922 1,617,751 Real estate construction: One-to-four family residential: Land and acquisition 4,099 — — — — 318 4,417 Residential construction 212,303 93 — — 93 — 212,396 Commercial and multifamily residential: Income property 194,912 — — — — — 194,912 Owner occupied 79,805 7,258 — — 7,258 — 87,063 Consumer 314,008 1,057 201 — 1,258 2,949 318,215 Total $ 8,218,651 $ 21,959 $ 6,299 $ — $ 28,258 $ 54,842 $ 8,301,751 The following is an analysis of the impaired loans (see Note 1, “Summary of Significant Accounting Policies,” ) as of December 31, 2019 and 2018 : Recorded Investment Recorded Investment Impaired Loans With Impaired Loans Without Recorded Unpaid Related Recorded Unpaid December 31, 2019 (in thousands) Commercial business: Secured $ 3,437,564 $ 24,083 $ 3,286 $ 3,851 $ 93 $ 20,797 $ 28,658 Unsecured 129,671 12 12 12 — — — Real estate: One-to-four family residential 264,513 382 299 588 5 83 182 Commercial and multifamily residential: Commercial land 300,973 2,217 1,592 1,601 312 625 663 Income property 2,059,361 — — — — — — Owner occupied 1,797,682 3,663 3,663 5,233 29 — — Real estate construction: One-to-four family residential: Land and acquisition 1,364 — — — — — — Residential construction 190,301 — — — — — — Commercial and multifamily residential: Income property 88,389 — — — — — — Owner occupied 73,203 — — — — — — Consumer 290,934 1,637 483 637 22 1,154 1,310 Total $ 8,633,955 $ 31,994 $ 9,335 $ 11,922 $ 461 $ 22,659 $ 30,813 Recorded Investment Recorded Investment Impaired Loans With Impaired Loans Without Recorded Unpaid Related Recorded Unpaid December 31, 2018 (in thousands) Commercial business: Secured $ 3,286,416 $ 26,285 $ 6,350 $ 8,460 $ 2,023 $ 19,935 $ 24,404 Unsecured 112,097 20 20 20 — — — Real estate: One-to-four family residential 235,138 888 325 798 8 563 575 Commercial and multifamily residential: Commercial land 283,451 2,226 — — — 2,226 2,272 Income property 1,917,522 2,954 99 165 1 2,855 3,011 Owner occupied 1,605,042 12,709 3,231 4,666 69 9,478 9,750 Real estate construction: One-to-four family residential Land and acquisition 4,417 — — — — — — Residential construction 212,396 — — — — — — Commercial and multifamily residential: Income property 194,912 — — — — — — Owner occupied 87,063 — — — — — — Consumer 314,193 4,022 3,326 3,584 31 696 704 Total $ 8,252,647 $ 49,104 $ 13,351 $ 17,693 $ 2,132 $ 35,753 $ 40,716 The following table provides additional information on impaired loans for the years ended December 31, 2019 , 2018 and 2017 : Years Ended December 31, 2019 2018 2017 Average Recorded Interest Recognized Average Recorded Interest Recognized Average Recorded Interest Recognized (in thousands) Commercial business Secured $ 24,682 $ 202 $ 39,701 $ 81 $ 20,282 $ 60 Unsecured 16 1 191 2 5 — Real estate: One-to-four family residential 665 42 748 42 730 49 Commercial and multifamily residential Commercial land 2,606 31 2,371 34 2,079 — Income property 1,121 — 3,284 130 4,314 51 Owner occupied 10,681 168 9,730 720 5,335 445 Real estate construction: One-to-four family residential Land and acquisition — — — — 3 — Residential construction — — 484 — 309 — Owner occupied — — 3,240 — 1,620 203 Consumer 2,960 8 5,712 129 5,973 163 Total $ 42,731 $ 452 $ 65,461 $ 1,138 $ 40,650 $ 971 The following is an analysis of loans classified as TDR for the years ended December 31, 2019 , 2018 and 2017 : Years Ended December 31, 2019 2018 2017 Number of TDR Modifications Pre-Modification Post-Modification Number of TDR Modifications Pre-Modification Post-Modification Number of TDR Modifications Pre-Modification Post-Modification (dollars in thousands) Commercial business: Secured 11 $ 6,642 $ 6,642 12 $ 18,379 $ 18,379 10 $ 5,655 $ 5,655 Unsecured — — — — — — 1 26 26 Real estate: One-to-four family residential 1 45 45 — — — 3 583 583 Commercial and multifamily residential: Commercial land — — — — — — 1 687 687 Income property 1 217 217 1 891 891 1 1,152 1,152 Owner occupied — — — — — — 1 78 78 Real estate construction: Commercial and multifamily residential: Owner occupied — — — — — — 1 4,050 4,050 Consumer 11 444 444 21 2,777 2,777 42 5,891 5,891 Total 24 $ 7,348 $ 7,348 34 $ 22,047 $ 22,047 60 $ 18,122 $ 18,122 The Company’s loans classified as TDR are loans that have been modified or the borrower has been granted special concessions due to financial difficulties, that if not for the challenges of the borrower, the Company would not otherwise consider. The Company had $1.1 million of commitments to lend additional funds on loans classified as TDR as of December 31, 2019 as compared to $2.1 million of similar commitments at December 31, 2018 . The TDR modifications or concessions are made to increase the likelihood that these borrowers with financial difficulties will be able to satisfy their debt obligations as amended. The concessions granted in the restructurings, summarized in the table above, largely consisted of maturity extensions, interest rate modifications or a combination of both. In limited circumstances, a reduction in the principal balance of the loan could also be made as a concession. Credit losses for loans classified as TDR are measured on the same basis as impaired loans. For impaired loans, an allowance is established when the collateral value less selling costs (or discounted cash flows or observable market price) of the impaired loan is lower than the recorded investment of that loan. The Company did have one $26 thousand consumer loan that defaulted within 12 months of being modified as a TDR during the year ended December 31, 2019 . This defaulted TDR loan did not impact the allowance for loan loss as it paid off prior to year end. The Company did not experience any similar defaults during the years ended December 31, 2018 and 2017 . PCI Loans PCI loans are accounted for under ASC 310-30 and initially measured at fair value based on expected future cash flows over the life of the loans. Loans that have common risk characteristics are aggregated into pools. The Company re-measures contractual and expected cash flows, at the pool-level, on a quarterly basis. Contractual cash flows are calculated based upon the loan pool terms after applying a prepayment factor. Calculation of the applied prepayment factor for contractual cash flows is the same as described below for expected cash flows. Inputs to the determination of expected cash flows include cumulative default and prepayment data as well as loss severity and recovery lag information. Cumulative default and prepayment data are calculated via a transition matrix. The transition matrix is a matrix of probability values that specifies the probability of a loan pool transitioning into a particular delinquency state (e.g. 0-30 days past due, 31 to 60 days, etc.) given its delinquency state at the re-measurement date. Loss severity factors are based upon either actual charge-off data within the loan pools or industry averages, and recovery lags are based upon the collateral within the loan pools. The excess of cash flows expected to be collected over the initial fair value of PCI loans is referred to as the accretable yield and is accreted into interest income over the estimated life of the acquired loans using the effective yield method. Other adjustments to the accretable yield include changes in the estimated remaining life of the acquired loans, changes in expected cash flows and changes of indices for acquired loans with variable interest rates. The following is an analysis of our PCI loans, net of related allowance for losses and remaining valuation discounts as of December 31, 2019 and 2018 : December 31, 2019 2018 (in thousands) Commercial business $ 8,083 $ 9,672 Real estate: One-to-four family residential 8,453 9,848 Commercial and multifamily residential 56,752 66,340 Total real estate 65,205 76,188 Real estate construction: One-to-four family residential — 153 Commercial and multifamily residential — 507 Total real estate construction — 660 Consumer 8,984 9,765 Subtotal of PCI loans 82,272 96,285 Less: Valuation discount resulting from acquisition accounting 4,756 6,525 ALLL 2,844 3,611 PCI loans, net of valuation discounts and allowance for loan losses $ 74,672 $ 86,149 The following table shows the changes in accretable yield for acquired loans for the years ended December 31, 2019 , 2018 , and 2017 : Years Ended December 31, 2019 2018 2017 (in thousands) Balance at beginning of period $ 21,949 $ 31,176 $ 45,191 Accretion (6,053 ) (8,194 ) (12,357 ) Disposals 46 (387 ) (158 ) Reclassifications from (to) nonaccretable difference 3,719 (646 ) (1,500 ) Balance at end of period $ 19,661 $ 21,949 $ 31,176 The Company did not acquire any loans accounted for under ASC 310-30 during 2019 or 2018 .

Allowance for Loan and Lease Lo

Allowance for Loan and Lease Losses and Unfunded Commitments and Letters of Credit	12 Months Ended
	Dec. 31, 2019
Allowance For Loan And Lease Losses And Unfunded Loan Commitments And Letters Of Credit
Allowance for Loan and Lease Losses and Unfunded Loan Commitments and Letters of Credit	Allowance for Loan and Lease Losses and Allowance for Unfunded Commitments and Letters of Credit We record an ALLL to recognize management’s estimate of credit losses incurred in the loan portfolio at each balance sheet date. We have used the same methodology for the ALLL calculation for the years ended December 31, 2019 and 2018 . The following tables show a detailed analysis of the ALLL for the years ended December 31, 2019 , 2018 and 2017 : Beginning Charge-offs Recoveries Provision (Recapture) Ending Specific General Year Ended December 31, 2019 (in thousands) Commercial business: Secured $ 43,188 $ (10,249 ) $ 2,755 $ 7,381 $ 43,075 $ 93 $ 42,982 Unsecured 2,626 (75 ) 350 184 3,085 — 3,085 Real estate: One-to-four family residential 593 (2 ) 242 (226 ) 607 5 602 Commercial and multifamily residential: Commercial land 3,947 — 286 2,146 6,379 312 6,067 Income property 4,044 — 320 2,062 6,426 — 6,426 Owner occupied 4,533 — 4 1,567 6,104 29 6,075 Real estate construction: One-to-four family residential: Land and acquisition 549 — 362 (799 ) 112 — 112 Residential construction 5,536 (170 ) 3,092 (3,982 ) 4,476 — 4,476 Commercial and multifamily residential: Income property 5,784 — 1 (3,286 ) 2,499 — 2,499 Owner occupied 2,604 — — 702 3,306 — 3,306 Consumer 5,301 (1,400 ) 930 (376 ) 4,455 22 4,433 PCI 3,611 (3,319 ) 3,979 (1,427 ) 2,844 — 2,844 Unallocated 1,053 — — (453 ) 600 — 600 Total $ 83,369 $ (15,215 ) $ 12,321 $ 3,493 $ 83,968 $ 461 $ 83,507 Beginning Charge-offs Recoveries Provision (Recapture) Ending Specific General Year Ended December 31, 2018 (in thousands) Commercial business: Secured $ 29,341 $ (11,560 ) $ 3,024 $ 22,383 $ 43,188 $ 2,023 $ 41,165 Unsecured 2,000 (159 ) 403 382 2,626 — 2,626 Real estate: One-to-four family residential 701 — 408 (516 ) 593 8 585 Commercial and multifamily residential: Commercial land 4,265 — 99 (417 ) 3,947 — 3,947 Income property 5,672 (780 ) 912 (1,760 ) 4,044 1 4,043 Owner occupied 5,459 — 20 (946 ) 4,533 69 4,464 Real estate construction: One-to-four family residential: Land and acquisition 963 — 726 (1,140 ) 549 — 549 Residential construction 3,709 — 890 937 5,536 — 5,536 Commercial and multifamily residential: Income property 7,053 — — (1,269 ) 5,784 — 5,784 Owner occupied 4,413 — — (1,809 ) 2,604 — 2,604 Consumer 5,163 (1,194 ) 1,180 152 5,301 31 5,270 PCI 6,907 (4,862 ) 3,847 (2,281 ) 3,611 — 3,611 Unallocated — — — 1,053 1,053 — 1,053 Total $ 75,646 $ (18,555 ) $ 11,509 $ 14,769 $ 83,369 $ 2,132 $ 81,237 Beginning Charge-offs Recoveries Provision (Recapture) Ending Specific General Year Ended December 31, 2017 (in thousands) Commercial business: Secured $ 36,050 $ (7,524 ) $ 4,283 $ (3,468 ) $ 29,341 $ 1,867 $ 27,474 Unsecured 960 (89 ) 553 576 2,000 3 1,997 Real estate: One-to-four family residential 599 (460 ) 568 (6 ) 701 103 598 Commercial and multifamily residential: Commercial land 1,797 — 53 2,415 4,265 — 4,265 Income property 7,342 (287 ) 498 (1,881 ) 5,672 185 5,487 Owner occupied 6,439 — 124 (1,104 ) 5,459 3 5,456 Real estate construction: One-to-four family residential: Land and acquisition 316 (14 ) 72 589 963 — 963 Residential construction 669 — 106 2,934 3,709 — 3,709 Commercial and multifamily residential: Income property 404 — 1 6,648 7,053 — 7,053 Owner occupied 1,192 — — 3,221 4,413 — 4,413 Consumer 3,534 (1,474 ) 1,187 1,916 5,163 199 4,964 PCI 10,515 (6,812 ) 6,187 (2,983 ) 6,907 — 6,907 Unallocated 226 — — (226 ) — — — Total $ 70,043 $ (16,660 ) $ 13,632 $ 8,631 $ 75,646 $ 2,360 $ 73,286 Changes in the allowance for unfunded commitments and letters of credit, a component of “Other liabilities” in the Consolidated Balance Sheets, are summarized as follows: Years Ended December 31, 2019 2018 2017 (in thousands) Beginning balance $ 4,330 $ 3,130 $ 2,705 Net changes in the allowance for unfunded commitments and letters of credit (900 ) 1,200 425 Ending balance $ 3,430 $ 4,330 $ 3,130 Risk Elements The extension of credit in the form of loans or other credit products to individuals and businesses is one of our principal business activities. Our policies and applicable laws and regulations require risk analysis as well as ongoing portfolio and credit management. We manage our credit risk through lending limit constraints, credit review, approval policies and extensive, ongoing internal monitoring. We also manage credit risk through diversification of the loan portfolio by type of loan, type of industry and type of borrower and by limiting the aggregation of debt to a single borrower. Risk ratings are reviewed and updated whenever appropriate, with more periodic reviews as the risk and dollar value of loss on the loan increases. In the event full collection of principal and interest is not reasonably assured, the loan is appropriately downgraded and, if warranted, placed on nonaccrual status even though the loan may be current as to principal and interest payments. Additionally, we assess whether an impairment of a loan warrants specific reserves or a write-down of the loan. Pass rated loans are generally considered to have sufficient sources of repayment in order to repay the loan in full in accordance with all terms and conditions. Special Mention rated loans have potential weaknesses that, if left uncorrected, may result in deterioration of the repayment prospects for the asset or in the Company’s credit position at some future date. Loans with a risk rating of Substandard or worse are reviewed to assess the ability of our borrowers to service all interest and principal obligations and, as a result, the risk rating may be adjusted accordingly. Loans risk rated as Substandard reflect loans where a loss is possible if loan weaknesses are not corrected. Doubtful rated loans have a high probability of loss; however, the amount of loss has not yet been determined. Loss rated loans are considered uncollectable and when identified, are charged-off. The following is an analysis of the credit quality of our loan portfolio, excluding PCI loans as of December 31, 2019 and 2018 : Pass Special Mention Substandard Doubtful Loss Total December 31, 2019 (in thousands) Loans, excluding PCI loans Commercial business: Secured $ 3,296,776 $ 37,394 $ 127,477 $ — $ — $ 3,461,647 Unsecured 129,518 — 165 — — 129,683 Real estate: One-to-four family residential 264,051 — 844 — — 264,895 Commercial and multifamily residential: Commercial land 283,254 1,344 18,592 — — 303,190 Income property 2,014,233 5,658 39,470 — — 2,059,361 Owner occupied 1,757,757 6,158 37,430 — — 1,801,345 Real estate construction: One-to-four family residential: Land and acquisition 1,364 — — — — 1,364 Residential construction 190,301 — — — — 190,301 Commercial and multifamily residential: Income property 88,389 — — — — 88,389 Owner occupied 73,203 — — — — 73,203 Consumer 289,588 — 2,983 — — 292,571 Total $ 8,388,434 $ 50,554 $ 226,961 $ — $ — 8,665,949 Less: ALLL 81,124 Loans, excluding PCI loans, net $ 8,584,825 Pass Special Mention Substandard Doubtful Loss Total December 31, 2018 (in thousands) Loans, excluding PCI loans Commercial business: Secured $ 3,160,910 $ 48,779 $ 103,007 $ 5 $ — $ 3,312,701 Unsecured 112,091 21 — 5 — 112,117 Real estate: One-to-four family residential 234,416 — 1,610 — — 236,026 Commercial and multifamily residential: Commercial land 276,348 5,082 4,247 — — 285,677 Income property 1,876,925 36,998 6,553 — — 1,920,476 Owner occupied 1,556,852 14,964 45,935 — — 1,617,751 Real estate construction: One-to-four family residential: Land and acquisition 4,099 — 318 — — 4,417 Residential construction 212,225 — 171 — — 212,396 Commercial and multifamily residential: Income property 194,912 — — — — 194,912 Owner occupied 87,063 — — — — 87,063 Consumer 313,817 — 4,398 — — 318,215 Total $ 8,029,658 $ 105,844 $ 166,239 $ 10 $ — 8,301,751 Less: ALLL 79,758 Loans, excluding PCI loans, net $ 8,221,993 The following is an analysis of the credit quality of our PCI loan portfolio as of December 31, 2019 and 2018 : Pass Special Mention Substandard Doubtful Loss Total December 31, 2019 (in thousands) PCI loans: Commercial business: Secured $ 6,109 $ 962 $ 606 $ — $ — $ 7,677 Unsecured 406 — — — — 406 Real estate: One-to-four family residential 8,351 — 102 — — 8,453 Commercial and multifamily residential: Commercial land 8,720 497 212 — — 9,429 Income property 18,386 — 297 — — 18,683 Owner occupied 21,077 — 7,563 — — 28,640 Consumer 8,758 — 226 — — 8,984 Total $ 71,807 $ 1,459 $ 9,006 $ — $ — 82,272 Less: Valuation discount resulting from acquisition accounting 4,756 ALLL 2,844 PCI loans, net $ 74,672 Pass Special Mention Substandard Doubtful Loss Total December 31, 2018 (in thousands) PCI loans: Commercial business: Secured $ 8,041 $ — $ 840 $ — $ — $ 8,881 Unsecured 692 — 99 — — 791 Real estate: One-to-four family residential 9,633 — 215 — — 9,848 Commercial and multifamily residential: Commercial land 10,363 — — — — 10,363 Income property 19,680 — — — — 19,680 Owner occupied 35,944 — 353 — — 36,297 Real estate construction: One-to-four family residential: Land and acquisition 151 — 2 — — 153 Commercial and multifamily residential: Income property 507 — — — — 507 Consumer 9,326 — 439 — — 9,765 Total $ 94,337 $ — $ 1,948 $ — $ — 96,285 Less: Valuation discount resulting from acquisition accounting 6,525 ALLL 3,611 PCI loans, net $ 86,149

Other Real Estate Owned

Other Real Estate Owned	12 Months Ended
	Dec. 31, 2019
Other Real Estate, Foreclosed Assets, and Repossessed Assets [Abstract]
Other Real Estate Owned	Other Real Estate Owned The following table sets forth activity in OREO for the periods indicated: Years Ended December 31, 2019 2018 (in thousands) Balance, beginning of period $ 6,019 $ 13,298 Transfers in 386 1,200 Valuation adjustments (195 ) (698 ) Proceeds from sale of OREO property (6,455 ) (7,261 ) Gain (loss) on sale of OREO, net 797 (520 ) Balance, end of period $ 552 $ 6,019 At December 31, 2019 , the carrying amount of foreclosed residential real estate properties held as a result of obtaining physical possession was $311 thousand and the recorded investment of consumer mortgage loans secured by residential real estate properties for which formal foreclosure proceedings were in process was $875 thousand .

Premises and Equipment

Premises and Equipment	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Premises and Equipment	Premises and Equipment Real and personal property and software, less accumulated depreciation and amortization, were as follows: December 31, 2019 2018 (in thousands) Land $ 53,124 $ 54,185 Buildings 107,371 108,890 Leasehold improvements 28,459 27,859 Furniture and equipment 37,929 32,292 Vehicles 510 511 Computer software 15,936 19,358 Total cost 243,329 243,095 Less accumulated depreciation and amortization (77,921 ) (74,307 ) Total $ 165,408 $ 168,788 Total depreciation and amortization expense was $10.3 million , $10.4 million , and $9.8 million , for the years ended December 31, 2019 , 2018 , and 2017 , respectively.

Goodwill and Intangible Assets

Goodwill and Intangible Assets	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill and Intangible Assets	Goodwill and Other Intangible Assets In accordance with the Intangibles – Goodwill and Other topic of the FASB ASC, goodwill is not amortized but is reviewed for potential impairment at the reporting unit level. Management analyzes its goodwill for impairment on an annual basis and between annual tests in certain circumstances such as upon material adverse changes in legal, business, regulatory and economic factors. An impairment loss is recorded to the extent that the carrying amount of goodwill exceeds its implied fair value. The Company performed its annual impairment assessment as of July 31, 2019 and concluded that there was no impairment. As of December 31, 2019 , we determined there were no events or circumstances which would more likely than not reduce the fair value of our reporting unit below its carrying amount. The CDI is evaluated for impairment if events and circumstances indicate a possible impairment. The CDI is amortized on an accelerated basis over an estimated life of 10 years . The following table sets forth activity for goodwill and other intangible assets for the periods indicated: Years Ended December 31, 2019 2018 2017 (in thousands) Goodwill, beginning of period $ 765,842 $ 765,842 $ 382,762 Established through acquisitions (1) — — 383,080 Total goodwill, end of period 765,842 765,842 765,842 Other intangible assets, net CDI: Gross CDI balance, beginning of period 105,473 105,473 58,598 Accumulated amortization, beginning of period (60,455 ) (48,219 ) (41,886 ) CDI, net, beginning of period 45,018 57,254 16,712 Established through acquisitions (1) — — 46,875 CDI current period amortization (10,479 ) (12,236 ) (6,333 ) Total CDI, end of period 34,539 45,018 57,254 Intangible assets not subject to amortization 919 919 919 Other intangible assets, net at end of period 35,458 45,937 58,173 Total goodwill and intangible assets, end of period $ 801,300 $ 811,779 $ 824,015 __________ (1) See Note 2, “Business Combinations,” for additional information regarding the goodwill and CDI related to the acquisition of Pacific Continental on November 1, 2017. The following table provides the estimated future amortization expense of CDI for the succeeding five years: Years Ending December 31, (in thousands) 2020 $ 8,724 2021 7,264 2022 5,880 2023 4,552 2024 3,432

Leases

Leases	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Lessee, Operating Leases [Text Block]	Leases Lease Commitments: The Company’s lease commitments consist primarily of leased locations under various non-cancellable operating leases that expire between 2020 and 2043 . The majority of the leases contain renewal options and provisions for increases in rental rates based on an agreed upon index or predetermined escalation schedule. The following table shows the details of the Company’s operating lease right-of-use asset and the associated lease liability for the period indicated: Item Balance Sheet Location December 31, 2019 (in thousands) Operating lease asset Other assets $ 57,226 Operating lease liability Other liabilities $ 63,030 At December 31, 2019 , the Company’s operating leases have a weighted average remaining lease term of 7.7 years and a weighted average discount rate of 3.0% . Cash paid for amounts included in the measurement of operating lease liabilities was $11.2 million for the year ended December 31, 2019 . Right-of-use assets obtained in exchange for new operating lease liabilities during the year ended December 31, 2019 were $20.6 million . The following table shows the components of net lease costs: Item Statement of Income Location Year Ended December 31, 2019 (in thousands) Operating lease cost (1) Occupancy $ 10,851 Variable lease cost Occupancy 1,805 Sublease income Occupancy (1,182 ) Net lease cost $ 11,474 __________ (1) Includes short-term lease costs, which are immaterial. Total rental expense on buildings and equipment, net of rental income of $1.2 million and $791 thousand for the years ended December 31, 2018 and 2017 , respectively, was $9.6 million and $7.9 million for the years ended December 31, 2018 and 2017 , respectively. The following table shows the maturity analysis for operating leases as of December 31, 2019 : Year ending December 31, (in thousands) 2020 $ 11,105 2021 11,126 2022 10,689 2023 9,476 2024 6,980 Thereafter 21,866 Total future minimum lease payments 71,242 Amounts representing interest (8,212 ) Present value of minimum lease payments $ 63,030 Future minimum lease payments for the Company’s operating leases as of December 31, 2018, prior to the adoption of the new lease guidance were as follows: Year Ending December 31, (in thousands) 2019 $ 10,947 2020 9,766 2021 8,729 2022 8,102 2023 6,796 Thereafter 18,703 Total minimum payments $ 63,043 Sale-leaseback transactions: On September 26, 2019, the Company sold one of its Washington facilities and leased back a portion of the facility utilized for branch operations. The lease term is through September 2022, with monthly payments of approximately $19 thousand . The sale-leaseback transaction resulted in a pre-tax gain of $5.9 million . For additional detail regarding the new lease guidance, see Note 1 , “Summary of Significant Accounting Policies and Reclassifications.”

Deposits

Deposits	12 Months Ended
	Dec. 31, 2019
Deposits [Abstract]
Deposits	Deposits Year end deposits are summarized in the following table: December 31, 2019 2018 (in thousands) Demand and other noninterest-bearing $ 5,328,146 $ 5,227,216 Money market (1) 2,322,644 2,294,125 Interest-bearing demand (1) 1,150,437 1,084,863 Savings (1) 882,050 889,849 Interest-bearing public funds, other than certificates of deposit (1) 301,203 233,938 Certificates of deposit, less than $250,000 218,764 243,849 Certificates of deposit, $250,000 or more 151,995 89,473 Certificates of deposit insured by CDARS ® 17,065 23,580 Brokered certificates of deposit 12,259 57,930 Reciprocal money market accounts 300,158 313,692 Subtotal 10,684,721 10,458,515 Valuation adjustment resulting from acquisition accounting (13 ) (389 ) Total deposits $ 10,684,708 $ 10,458,126 __________ (1) Beginning in 2019, interest-bearing public funds, other than certificates of deposit, are presented separately in this table. Prior period amounts have been reclassified to conform to current period presentation. Overdrafts of $3.8 million and $4.0 million were reclassified as loan balances at December 31, 2019 and 2018 , respectively. The following table shows the amount and maturity of time deposits: Years Ending December 31, (in thousands) 2020 $ 313,241 2021 53,679 2022 19,346 2023 8,060 2024 5,593 Thereafter 151 Total $ 400,070

Federal Home Loan Bank and Fede

Federal Home Loan Bank and Federal Reserve Bank Borrowings	12 Months Ended
	Dec. 31, 2019
Federal Home Loan Bank and Federal Reserve Bank Borrowings [Abstract]
Federal Home Loan Bank and Federal Reserve Bank Borrowings [Text Block]	FHLB and FRB Borrowings FHLB The Company has entered into borrowing arrangements with the FHLB to borrow funds under a short-term floating rate fed funds overnight advance program and fixed-term loan agreements. All borrowings are secured by stock of the FHLB and a blanket pledge of qualifying loans receivable. The Company had aggregate borrowing capacity with the FHLB of $1.96 billion and $1.62 billion for the years ended December 31, 2019 and 2018 , respectively, of which the Company had borrowed $953.0 million and $399.0 million , respectively. See Note 5, “Loans ,” for the carrying value of pledged loans. At December 31, 2019 , FHLB advances were scheduled to mature as follows: Federal Home Loan Bank Advances Weighted Average Rate Amount (dollars in thousands) Within 1 year 1.82 % $ 946,000 Over 1 through 5 years 3.85 % 2,000 Due after 10 years 5.37 % 5,000 Total 953,000 Valuation adjustment from acquisition accounting 469 Total $ 953,469 The maximum, average outstanding and year end balances and average interest rates on advances from the FHLB were as follows for the years ended December 31, 2019 , 2018 and 2017 : Years ended December 31, 2019 2018 2017 (dollars in thousands) Balance at end of period $ 953,469 $ 399,523 $ 11,579 Average balance during period $ 469,983 $ 166,563 $ 79,788 Maximum month end balance during period $ 953,469 $ 399,523 $ 317,480 Weighted average rate during period 2.42 % 2.29 % 1.33 % Weighted average rate at December 31 1.84 % 2.68 % 4.08 % FRB The Company is also eligible to borrow under the FRB’s primary credit program, including the Term Auction Facility auctions. All borrowings are secured by certain pledged, available for sale investment securities. While the Company had no borrowings as of December 31, 2019 and December 31, 2018 , there were overnight borrowings resulting in average borrowings of $99 thousand and $14 thousand for 2019 and 2018 , respectively. The Company had no borrowings in 2017 . The Company pledges securities and loans for borrowing capacity at the FRB and had a borrowing capacity with the FRB of $209.1 million and $107.1 million for the years ended December 31, 2019 and 2018 , respectively. See Note 4, “Securities,” for the carrying value of pledged investment securities and Note 5, “Loans,” for the carrying value of pledged loans.

Securities Sold Under Agreement

Securities Sold Under Agreements to Repurchase	12 Months Ended
	Dec. 31, 2019
Securities Sold under Agreements to Repurchase [Abstract]
Securities sold under agreements to repurchase	Securities Sold Under Agreements to Repurchase Securities Sold Under Agreements to Repurchase - Term The Company had previously entered into wholesale repurchase agreements with certain brokers. At December 31, 2017, the Company held $25.0 million in wholesale repurchase agreements with an interest rate of 1.88% . These agreements were settled on the repurchase date of March 19, 2018. Securities Sold Under Agreements to Repurchase - Sweep Sweep repurchase agreements are generally short-term agreements. These agreements are treated as financing transactions and the obligations to repurchase securities sold are reflected as a liability in the Consolidated Financial Statements. The dollar amount of securities underlying the agreements remains in the applicable asset account of the Consolidated Financial Statements. These agreements had a balance of $64.4 million and a weighted average interest rate of 1.24% at December 31, 2019 . All of these repurchase agreements in existence at December 31, 2019 mature on a daily basis. Securities available for sale with a carrying amount of $76.0 million at December 31, 2019 were pledged as collateral for the sweep repurchase agreement borrowings.

Subordinated debentures

Subordinated debentures	12 Months Ended
	Dec. 31, 2019
Subordinated Borrowing [Line Items]
Subordinated Borrowings Disclosure [Text Block]	Subordinated Debentures On November 1, 2017, with its acquisition of Pacific Continental, the Company assumed $35.0 million in aggregate principal amount of fixed-to-floating rate subordinated debentures. These debentures are callable at par on June 30, 2021, have a stated maturity of June 30, 2026 and bear interest at a fixed annual rate of 5.875% per year, from and including June 27, 2016, but excluding June 30, 2021. From and including June 30, 2021 through the maturity date or early redemption date, the interest rate will reset quarterly to an annual interest rate equal to the then-current three-month LIBOR plus 4.715% .

Revolving line of credit

Revolving line of credit	12 Months Ended
	Dec. 31, 2019
Line of Credit [Member]
Line of Credit Facility [Line Items]
Short-term Debt [Text Block]	Revolving Line of Credit During the second quarter of 2019, the Company entered into a $30.0 million short-term credit facility with an unaffiliated bank that matures in May 2020. This facility has a variable interest rate and provides the Company additional liquidity, if needed, for various corporate activities including the repurchase of shares of Columbia Banking System, Inc. common stock. As of December 31, 2019 , there was no outstanding balance. The credit agreement requires the Company to comply with certain covenants including those related to asset quality and capital levels. The Company was in compliance with all covenants associated with this facility at December 31, 2019 .

Derivatives and Balance Sheet O

Derivatives and Balance Sheet Offsetting	12 Months Ended
	Dec. 31, 2019
General Discussion of Derivative Instruments and Hedging Activities [Abstract]
Derivatives and Balance Sheet Offsetting	Derivatives and Balance Sheet Offsetting The Company is exposed to certain risks arising from both its business and economic conditions. The Company principally manages its exposures to a wide variety of business and operational risks through management of its core business activities. The Company manages economic risks, including interest rate, liquidity, and credit risk, primarily by managing the amount, sources, and duration of its assets and liabilities and the use of derivative financial instruments. Specifically, the Company enters into interest rate-based derivative financial instruments to manage exposures that arise from business activities that result in the receipt or payment of future known and uncertain cash amounts,. The Company’s derivative financial instruments are used to manage differences in the amount, timing, and duration of the Company’s known or expected cash receipts and its known or expected cash payments principally related to the Company’s loan portfolio. The Company’s objectives in using interest rate derivatives are to add stability to interest income and to manage its exposure to interest rate movements. To accomplish this objective, the Company uses interest rate collars as part of its interest rate risk management strategy. Interest rate collars designated as cash flow hedges involve the payments of variable-rate amounts if interest rates rise above the cap strike rate on the contract and receipts of variable-rate amounts if interest rates fall below the floor strike rate on the contract. These derivative contracts are used to hedge the variable cash flows associated with existing variable-rate assets. With respect to derivatives designated and that qualify as cash flow hedges of interest rate risk, the gain or loss on the derivative is recorded in accumulated other comprehensive income (loss) and subsequently reclassified into interest income in the same period(s) during which the hedged transaction affects earnings. Amounts reported in accumulated other comprehensive income (loss) related to derivatives will be reclassified to interest income as interest payments are received on the Company’s variable-rate assets. During the next 12 months, the Company estimates that there will be $3.2 million reclassified as an increase to interest income. In addition, the Company periodically enters into certain commercial loan interest rate swap agreements in order to provide commercial loan customers the ability to convert from variable to fixed interest rates. Under these agreements, the Company enters into a variable-rate loan agreement with a customer in addition to a swap agreement. This swap agreement effectively converts the customer’s variable rate loan into a fixed rate loan. The Company then enters into a corresponding swap agreement with a third party in order to offset its exposure on the variable and fixed components of the customer agreement. As the interest rate swap agreements with the customers and third parties are not designated as hedges under the Derivatives and Hedging topic of the FASB ASC, the instruments are marked to market in earnings. The notional amount of open interest rate swap agreements at December 31, 2019 and 2018 was $428.6 million and $366.7 million , respectively. Mark-to-market loss of $1 thousand for 2019 and mark-to-market gains of $8 thousand and $16 thousand for 2018 and 2017 , respectively, were recorded to “Other” noninterest expense. The following table presents the fair value of derivatives, as well as their classification on the Balance Sheet at December 31, 2019 and 2018 : Asset Derivatives Liability Derivatives 2019 2018 2019 2018 Balance Sheet Fair Value Balance Sheet Fair Value Balance Sheet Fair Value Balance Sheet Fair Value (in thousands) Derivatives designated as hedging instruments: Interest rate collar Other assets $ 14,727 Other assets $ — Other liabilities $ — Other liabilities $ — Derivatives not designated as hedging instruments: Interest rate swap contracts Other assets $ 19,144 Other assets $ 7,033 Other liabilities $ 19,145 Other liabilities $ 7,033 The table below presents the effect of cash flow hedge accounting on accumulated other comprehensive income (loss) for the years ended December 31, 2019 and 2018 : Amount of Gain or (Loss) Recognized in Accumulated Other Comprehensive Income on Derivative Location of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income into Income Amount of Gain or (Loss) Reclassified from Accumulated Other Comprehensive Income into Income Years Ended December 31, Years Ended December 31, 2019 2018 2019 2018 (in thousands) Interest rate collar $ 15,322 $ — Interest income $ 595 $ — The notional amount of the interest rate collar was $500.0 million at December 31, 2019 . The cash flow hedge was determined to be effective during the periods presented and, as a result, qualifies for hedge accounting treatment. The Company is party to interest rate swap contracts, interest rate collar and repurchase agreements that are subject to enforceable master netting arrangements or similar agreements. Under these agreements, the Company may have the right to net settle multiple contracts with the same counterparty. The following tables show the gross interest rate swap contracts, collar agreements and repurchase agreements in the Consolidated Balance Sheets and the respective collateral received or pledged in the form of cash or other financial instruments. The collateral amounts in these tables are limited to the outstanding balances of the related asset or liability. Therefore, instances of overcollateralization are not shown. Gross Amounts of Recognized Assets/Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheets Gross Amounts Not Offset in the Consolidated Balance Sheets Collateral Pledged/Received Net Amount December 31, 2019 (in thousands) Assets Interest rate swap contracts $ 19,144 $ — $ 19,144 $ — $ 19,144 Interest rate collar $ 14,727 $ — $ 14,727 $ (14,727 ) $ — Liabilities Interest rate swap contracts $ 19,145 $ — $ 19,145 $ (19,145 ) $ — Repurchase agreements $ 64,437 $ — $ 64,437 $ (64,437 ) $ — December 31, 2018 Assets Interest rate swap contracts $ 7,033 $ — $ 7,033 $ — $ 7,033 Liabilities Interest rate swap contracts $ 7,033 $ — $ 7,033 $ (3,235 ) $ 3,798 Repurchase agreements $ 61,094 $ — $ 61,094 $ (61,094 ) $ — The Company’s agreements with each of its derivative counterparties provide that if the Company defaults or is capable of being declared in default on any of its indebtedness, the Company could also be declared in default on its derivative obligations. The following table presents the class of collateral pledged for repurchase agreements as well as the remaining contractual maturity of the repurchase agreements: Remaining contractual maturity of the agreements Overnight and continuous Up to 30 days 30 - 90 days Greater than 90 days Total December 31, 2019 (in thousands) Class of collateral pledged for repurchase agreements U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations $ 64,437 $ — $ — $ — $ 64,437 Gross amount of recognized liabilities for repurchase agreements 64,437 Amounts related to agreements not included in offsetting disclosure $ — The collateral utilized for the Company’s repurchase agreements is subject to market fluctuations as well as prepayments of principal. The Company monitors the risk of the fair value of its pledged collateral falling below acceptable amounts based on the type of the underlying repurchase agreement. The pledged collateral related to the Company’s $64.4 million sweep repurchase agreements, which mature on an overnight basis, is monitored on a daily basis as the underlying sweep accounts can have frequent transaction activity and the amount of pledged collateral is adjusted as necessary.

Employee Benefit Plans

Employee Benefit Plans	12 Months Ended
	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Benefit Plans	Employee Benefit Plans 401(k) Plan The Company maintains defined contribution and profit sharing plans in conformity with the provisions of section 401(k) of the Internal Revenue Code. The Columbia Bank 401(k) Plan, permits Columbia Bank employees who are at least 18 years of age to contribute up to 75% of their eligible compensation to the 401(k) Plan starting on the first day of the month following their hire date. On a per pay period basis the Company is required to match 50% of employee contributions up to 3% of each employee’s eligible compensation. The Company contributed $3.5 million during 2019 , $3.3 million during 2018 , and $2.7 million during 2017 , in matching funds to the 401(k) Plan. Additionally, as determined annually by the board of directors of the Company, the 401(k) Plan provides for a non-matching discretionary profit sharing contribution. The Company’s discretionary profit sharing contributions were $7.3 million during 2019 , $7.0 million during 2018 and $5.7 million during 2017 . Employee Stock Purchase Plan The Company maintains an ESP Plan in which substantially all employees of the Company are eligible to participate. The ESP Plan provides participants the opportunity to purchase common stock of the Company at a discounted price. Under the ESP Plan, participants can purchase common stock of the Company for 90% of the lowest price on either the first or last day in each of two six month look-back periods. The look-back periods are January 1st through June 30th and July 1st through December 31st of each calendar year. The 10% discount is recognized by the Company as compensation expense and does not have a material impact on net income or earnings per common share. Participants of the ESP Plan purchased 57,201 shares for $2.1 million in 2019 , 50,750 shares for $2.0 million in 2018 and 38,387 shares for $1.5 million in 2017 . At December 31, 2019 there were 303,156 shares available for purchase under the ESP Plan. Supplemental Compensation Plan The Company maintains Unit Plans to provide benefits for certain employees. The Unit Plans generally vest over a 10 year period and provide a fixed annual benefit over the subsequent 10 year period. At December 31, 2019 and 2018 , the liability associated with these plans was $4.0 million and $4.2 million , respectively. Expense associated with these plans for the years ended December 31, 2019 , 2018 and 2017 was $415 thousand , $337 thousand and $452 thousand , respectively. Supplemental Executive Retirement Plan The Company maintains a SERP, a nonqualified deferred compensation plan that provides retirement benefits to certain highly compensated executives. The SERP is unsecured and unfunded and there are no program assets. The SERP projected benefit obligation, which represents the vested net present value of future payments to individuals under the plan is accrued over the estimated remaining term of employment of the participants and has been determined by actuarial valuation using a discount rate of 3.34% for 2019 and 4.30% for 2018 . Additional assumptions and features of the plan are a normal retirement age of 65 and a 2% annual cost of living benefit adjustment. The projected benefit obligation is included in “Other liabilities” on the Consolidated Balance Sheets. The following table reconciles the accumulated liability for the projected benefit obligation: December 31, 2019 2018 (in thousands) Balance, beginning of year $ 21,287 $ 20,553 Actuarial (gain) loss 2,663 (31 ) Benefit expense 1,930 1,701 Benefit payments (966 ) (936 ) Balance, end of year $ 24,914 $ 21,287 The benefits expected to be paid in conjunction with the SERP are presented in the following table: Years Ending December 31, (in thousands) 2020 $ 1,971 2021 1,116 2022 1,135 2023 1,239 2024 1,438 2025 through 2029 8,574 Total $ 15,473

Commitments and Contingent Liab

Commitments and Contingent Liabilities	12 Months Ended
	Dec. 31, 2019
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingent Liabilities	Commitments and Contingent Liabilities Financial Instruments with Off-Balance Sheet Risk: In the normal course of business, the Company makes loan commitments (typically unfunded loans and unused lines of credit) and issues standby letters of credit to accommodate the financial needs of its customers. Standby letters of credit commit the Company to make payments on behalf of customers under specified conditions. Historically, no significant losses have been incurred by the Company under standby letters of credit. Both arrangements have credit risk essentially the same as that involved in extending loans to customers and are subject to the Company’s normal credit policies, including collateral requirements, where appropriate. At December 31, 2019 and 2018 , the Company’s loan commitments were $2.67 billion and $2.62 billion , respectively. Standby letters of credit were $25.7 million and $28.3 million at December 31, 2019 and 2018 , respectively. In addition, there were no commitments under commercial letters of credit used to facilitate customers’ trade transactions and other off-balance sheet liabilities at December 31, 2019 and 2018 . Legal Proceedings: The Company and its subsidiaries are from time to time defendants in and are threatened with various legal proceedings arising from their regular business activities. Management, after consulting with legal counsel, is of the opinion that the ultimate liability, if any, resulting from these pending or threatened actions and proceedings will not have a material effect on the financial statements of the Company.

Shareholders' Equity

Shareholders' Equity	12 Months Ended
	Dec. 31, 2019
Stockholders' Equity Note [Abstract]
Shareholders' Equity	Shareholders’ Equity Dividends. The following summarizes the dividend activity for the year ended December 31, 2019 : Declared Regular Cash Dividends Per Common Share Special Cash Dividends Per Common Share Record Date Paid Date January 24, 2019 $ 0.28 $ 0.14 February 6, 2019 February 20, 2019 April 25, 2019 $ 0.28 $ 0.14 May 8, 2019 May 22, 2019 July 25, 2019 $ 0.28 $ — August 7, 2019 August 21, 2019 October 24, 2019 $ 0.28 $ — November 6, 2019 November 20, 2019 Subsequent to year end, on January 23, 2020 , the Company declared a regular quarterly cash dividend of $0.28 per common share and a special cash dividend of $0.22 per commons share payable on February 19, 2020 , to shareholders of record at the close of business on February 5, 2020 . The payment of cash dividends is subject to federal regulatory requirements for capital levels and other restrictions. In addition, the cash dividends paid by Columbia Bank to the Company are subject to both federal and state regulatory requirements. Share Repurchase Program: For the year ended December 31, 2019 , the Company repurchased 1.5 million shares of common stock at an average price of $35.00 per share. As of December 31, 2019 , there are 1.4 million remaining shares authorized to be repurchased under the current Board approved share repurchase program.

Accumulated Other Comprehensive

Accumulated Other Comprehensive Income	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income [Abstract]
Comprehensive Income (Loss) Note [Text Block]	Accumulated Other Comprehensive Income The following table shows changes in accumulated other comprehensive income (loss) by component for the years ended December 31, 2019 , 2018 and 2017 : Unrealized Gains and Losses on Available for Sale Securities (1) Unrealized Gains and Losses on Pension Plan Liability (1) Unrealized Gains and Losses on Hedging Instruments (1) Total (1) Year Ended December 31, 2019 (in thousands) Beginning balance $ (33,128 ) $ (2,177 ) $ — $ (35,305 ) Other comprehensive income (loss) before reclassifications 67,802 (2,042 ) 11,760 77,520 Amounts reclassified from accumulated other comprehensive loss (2) (1,636 ) 245 (457 ) (1,848 ) Net current-period other comprehensive income (loss) 66,166 (1,797 ) 11,303 75,672 Ending balance $ 33,038 $ (3,974 ) $ 11,303 $ 40,367 Year Ended December 31, 2018 Beginning balance $ (19,779 ) $ (2,446 ) $ — $ (22,225 ) Adjustment pursuant to adoption of ASU 2016-01 157 — — 157 Other comprehensive income (loss) before reclassifications (13,425 ) 24 — (13,401 ) Amounts reclassified from accumulated other comprehensive loss (2) (81 ) 245 — 164 Net current-period other comprehensive income (loss) (13,506 ) 269 — (13,237 ) Ending balance $ (33,128 ) $ (2,177 ) $ — $ (35,305 ) Year Ended December 31, 2017 Beginning balance $ (12,704 ) $ (6,295 ) $ — $ (18,999 ) Other comprehensive income (loss) before reclassifications (3,391 ) 4,017 — 626 Amounts reclassified from accumulated other comprehensive loss (2) 7 223 — 230 Net current-period other comprehensive income (loss) (3,384 ) 4,240 — 856 Adjustment pursuant to adoption of ASU 2018-02 $ (3,691 ) $ (391 ) $ — $ (4,082 ) Ending balance $ (19,779 ) $ (2,446 ) $ — $ (22,225 ) __________ (1) All amounts are net of tax. Amounts in parenthesis indicate debits. (2) See following table for details about these reclassifications. In December 2017, the Company made an election to reclassify income tax effects related to the Tax Cuts and Jobs Act of $4.1 million from accumulated other comprehensive income to retained earnings. The Company uses the portfolio approach to account for the tax consequences of amounts reported in OCI. The following table shows details regarding the reclassifications from accumulated other comprehensive income for the years ended December 31, 2019 , 2018 and 2017 : Amount Reclassified from Accumulated Other Comprehensive Income Affected line Item in the Consolidated Statement of Income Years Ended December 31, 2019 2018 2017 (in thousands) Unrealized gains and losses on available for sale debt securities $ 2,132 $ 106 $ (11 ) Investment securities gains (losses), net 2,132 106 (11 ) Total before tax (496 ) (25 ) 4 Income tax provision $ 1,636 $ 81 $ (7 ) Net of tax Amortization of pension plan liability actuarial losses $ (319 ) $ (319 ) $ (350 ) Compensation and employee benefits (319 ) (319 ) (350 ) Total before tax 74 74 127 Income tax provision $ (245 ) $ (245 ) $ (223 ) Net of tax Unrealized gains from hedging instruments $ 595 $ — $ — Loans 595 — — Total before tax (138 ) — — Income tax provision $ 457 $ — $ — Net of tax

Fair Value Accounting and Measu

Fair Value Accounting and Measurement	12 Months Ended
	Dec. 31, 2019
Fair Value Disclosures [Abstract]
Fair Value Accounting and Measurement	Fair Value Accounting and Measurement The Fair Value Measurements and Disclosures topic of the FASB ASC defines fair value, establishes a consistent framework for measuring fair value and expands disclosure requirements about fair value. We hold fixed and variable rate interest-bearing securities, investments in marketable equity securities and certain other financial instruments, which are carried at fair value. Fair value is determined based upon quoted prices when available or through the use of alternative approaches, such as matrix or model pricing, when market quotes are not readily accessible or available. The valuation techniques are based upon observable and unobservable inputs. Observable inputs reflect market data obtained from independent sources, while unobservable inputs reflect our own market assumptions. These two types of inputs create the following fair value hierarchy: Level 1 – Quoted prices for identical instruments in active markets that are accessible at the measurement date. Level 2 – Quoted prices for similar instruments in active markets; quoted prices for identical or similar instruments in markets that are not active; and model derived valuations whose inputs are observable or whose significant value drivers are observable. Level 3 – Prices or valuation techniques that require inputs that are both significant to the fair value measurement and unobservable. Fair values are determined as follows: Securities at fair value are priced using a combination of market activity, industry recognized information sources, yield curves, discounted cash flow models and other factors. These fair value calculations are considered a Level 2 input method under the provisions of the Fair Value Measurements and Disclosures topic of the FASB ASC for all securities other than U.S. Treasury Notes and other securities, which are considered a Level 1 input method. Interest rate contracts and the interest rate collar are valued in models, which use as their basis, readily observable market parameters and are classified within Level 2 of the valuation hierarchy. The following table sets forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis at December 31, 2019 and 2018 by level within the fair value hierarchy. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement: Fair Value at Fair Value Measurements at Reporting Date Using Level 1 Level 2 Level 3 (in thousands) Assets Debt securities available for sale U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,892,950 $ — $ 2,892,950 $ — Other asset-backed securities (1) 196,050 — 196,050 — State and municipal securities 488,802 — 488,802 — U.S. government agency and government-sponsored enterprise securities 168,340 — 168,340 — Total debt securities available for sale $ 3,746,142 $ — $ 3,746,142 $ — Other assets: Interest rate contracts $ 19,144 $ — $ 19,144 $ — Interest rate collar 14,727 — 14,727 — Liabilities Other liabilities: Interest rate contracts $ 19,145 $ — $ 19,145 $ — Fair Value at Fair Value Measurements at Reporting Date Using Level 1 Level 2 Level 3 (in thousands) Assets Debt securities available for sale U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,013,355 $ — $ 2,013,355 $ — Other asset-backed securities (1) 174,935 — 174,935 — State and municipal securities 574,323 — 574,323 — U.S. government agency and government-sponsored enterprise securities 404,587 — 404,587 — U.S. government securities 248 248 — — Total debt securities available for sale $ 3,167,448 $ 248 $ 3,167,200 $ — Other assets: Interest rate contracts $ 7,033 $ — $ 7,033 $ — Liabilities Other liabilities: Interest rate contracts $ 7,033 $ — $ 7,033 $ — __________ (1) Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation. There were no transfers between Level 1 and Level 2 of the valuation hierarchy during the years ended December 31, 2019 and 2018 . The Company recognizes transfers between levels of the valuation hierarchy based on the valuation level at the end of the reporting period. Nonrecurring Measurements Certain assets and liabilities are measured at fair value on a nonrecurring basis after initial recognition such as loans measured for impairment and OREO. The following methods were used to estimate the fair value of each such class of financial instrument: Impaired loans —A loan is considered to be impaired when, based on current information and events, it is probable that the Company will be unable to collect all amounts due (both interest and principal) according to the contractual terms of the loan agreement. Impaired loans are measured based on the present value of expected future cash flows discounted at the loan’s effective interest rate, a loan’s observable market price, or the fair market value of the collateral less estimated costs to sell if the loan is a collateral-dependent loan. The impairment evaluations are performed in conjunction with the ALLL process on a quarterly basis by officers in the Special Credits group, which reports to the Chief Credit Officer. The REASD, which also reports to the Chief Credit Officer, is responsible for obtaining appraisals from third-parties or performing internal evaluations. If an appraisal is obtained from a third-party, the REASD reviews the appraisal to evaluate the adequacy of the appraisal report, including its scope, methods, accuracy, and reasonableness. The following table sets forth the Company’s assets that were measured using fair value estimates on a nonrecurring basis during the years ended December 31, 2019 and 2018 : Fair Value at Fair Value Measurements at Reporting Date Using Losses During the Year Ended Level 1 Level 2 Level 3 (in thousands) Impaired loans $ 10,007 $ — $ — $ 10,007 $ 7,519 $ 10,007 $ — $ — $ 10,007 $ 7,519 Fair Value at Fair Value Measurements at Reporting Date Using Losses During the Year Ended Level 1 Level 2 Level 3 (in thousands) Impaired loans $ 11,555 $ — $ — $ 11,555 $ 1,821 $ 11,555 $ — $ — $ 11,555 $ 1,821 The losses on impaired loans disclosed above represent the amount of the specific reserve and/or charge-offs during the period applicable to loans held at period end. The amount of the specific reserve is included in the ALLL. Quantitative information about Level 3 fair value measurements The range and weighted average of the significant unobservable inputs used to fair value our Level 3 nonrecurring assets during 2019 and 2018 , along with the valuation techniques used, are shown in the following tables: Fair Value at Valuation Technique Unobservable Input Range (Weighted Average) (1) (dollars in thousands) Impaired loans - collateral-dependent (2) $ 10,007 Fair Market Value of Collateral Adjustment to Stated Value 0% - 100% (49.68%) __________ (1) Adjustment applied to appraisal value and stated value (in the case of fixed assets and inventory). (2) Collateral consists of accounts receivable, inventory, fixed assets, real estate and cash. Fair Value at Valuation Technique Unobservable Input Range (Weighted Average) (1) (dollars in thousands) Impaired loans - collateral-dependent (2) $ 8,394 Fair Market Value of Collateral Adjustment to Stated Value 0.00% - 70.04% (7.02%) Impaired loans - other (3) $ 3,161 Discounted Cash Flow Discount Rate 0.34 % __________ (1) Discount rate applied to discounted cash flow valuation or appraisal value and stated value (in the case of fixed assets and inventory). (2) Collateral consists of accounts receivable, inventory, fixed assets, real estate and cash. (3) As there was only one impaired loan re-measured using discounted cash flows, a range of discounts could not be provided. The following tables summarize carrying amounts and estimated fair values of selected financial instruments for the periods indicated: December 31, 2019 Carrying Fair Level 1 Level 2 Level 3 (in thousands) Assets Cash and due from banks $ 223,541 $ 223,541 $ 223,541 $ — $ — Interest-earning deposits with banks 24,132 24,132 24,132 — — Debt securities available for sale 3,746,142 3,746,172 — 3,746,172 — FHLB stock 48,120 48,120 — 48,120 — Loans held for sale 17,718 17,718 — 17,718 — Loans 8,659,497 8,883,865 — — 8,883,865 Interest rate contracts 19,144 19,144 — 19,144 — Interest rate collar 14,727 14,727 — 14,727 — Liabilities Time deposits $ 400,070 $ 397,736 $ — $ 397,736 $ — FHLB advances 953,469 952,762 — 952,762 — Repurchase agreements 64,437 64,437 — 64,437 — Subordinated debentures 35,277 35,491 — 35,491 — Interest rate contracts 19,145 19,145 — 19,145 — December 31, 2018 Carrying Fair Level 1 Level 2 Level 3 (in thousands) Assets Cash and due from banks $ 260,180 $ 260,180 $ 260,180 $ — $ — Interest-earning deposits with banks 17,407 17,407 17,407 — — Debt securities available for sale 3,167,448 3,167,448 248 3,167,200 — FHLB stock 25,960 25,960 — 25,960 — Loans held for sale 3,849 3,849 — 3,849 — Loans 8,308,142 8,316,946 — — 8,316,946 Interest rate contracts 7,033 7,033 — 7,033 — Liabilities Time deposits $ 414,443 $ 407,659 $ — $ 407,659 $ — FHLB advances 399,523 400,085 — 400,085 — Repurchase agreements 61,094 61,094 — 61,094 — Subordinated debentures 35,462 34,897 — 34,897 — Interest rate contracts 7,033 7,033 — 7,033 —

Earnings Per Common Share

Earnings Per Common Share	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Earnings Per Common Share	Earnings Per Common Share The Company applies the two-class method of computing basic and diluted EPS. Under the two-class method, EPS is determined for each class of common stock and participating security according to dividends declared and participation rights in undistributed earnings. The Company issues restricted shares under share-based compensation plans and preferred shares which qualify as participating securities. The following table sets forth the computation of basic and diluted EPS for the periods indicated: Years Ended December 31, 2019 2018 2017 (in thousands except per share amounts) Basic EPS: Net income $ 194,451 $ 172,882 $ 112,828 Less: Earnings allocated to participating securities Preferred shares — — 3 Nonvested restricted shares 1,530 1,892 1,501 Earnings allocated to common shareholders $ 192,921 $ 170,990 $ 111,324 Weighted average common shares outstanding 71,999 72,385 59,882 Basic earnings per common share $ 2.68 $ 2.36 $ 1.86 Diluted EPS: Earnings allocated to common shareholders $ 192,921 $ 170,990 $ 111,324 Weighted average common shares outstanding 71,999 72,385 59,882 Dilutive effect of equity awards and warrants 33 5 6 Weighted average diluted common shares outstanding 72,032 72,390 59,888 Diluted earnings per common share $ 2.68 $ 2.36 $ 1.86 Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive 8 4 13

Share-Based Payments

Share-Based Payments	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Share-Based Payments	Share-Based Payments At December 31, 2019 , the Company had one equity compensation plan (the “Plan”), which is shareholder approved, that provides for the granting of share options and shares to eligible employees and directors up to 3,050,000 shares. Share Awards: Restricted share awards provide for the immediate issuance of shares of Company common stock to the recipient, with such shares held in escrow until certain conditions are met. Share awards provides for vesting requirements that include time-based, performance-based, or market-based conditions. Recipients of restricted shares do not pay any cash consideration to the Company for the shares and the holders of the restricted shares have voting rights. For share awards issued under our new equity incentive plan approved in 2018, the holder accrues dividends, which are paid out when the shares vest. For any awards granted prior to the new plan, the holder receives dividends whether or not the shares have vested. The fair value of time-based and performance-based share awards is equal to the fair market value of the Company’s common stock on the date of grant. The fair value of market-based awards is estimated on the date of grant using the Monte Carlo simulation model. A summary of changes in the Company’s nonvested shares and related information for the years ended December 31, 2019 , 2018 and 2017 is presented below: Shares Weighted Nonvested at January 1, 2017 818,755 $ 27.19 Granted 337,384 $ 38.51 Vested (253,509 ) $ 25.67 Forfeited (96,924 ) $ 28.97 Nonvested at December 31, 2017 805,706 $ 32.23 Granted 306,592 $ 41.47 Vested (237,146 ) $ 28.78 Forfeited (61,012 ) $ 35.92 Nonvested at December 31, 2018 814,140 $ 36.43 Granted 405,516 $ 35.08 Vested (268,253 ) $ 32.50 Forfeited (62,386 ) $ 37.12 Nonvested at December 31, 2019 889,017 $ 36.96 As of December 31, 2019 , there was $23.1 million of total unrecognized compensation cost related to nonvested share-based compensation arrangements granted under the Plan. That cost is expected to be recognized over a weighted average period of 2.7 years. The total fair value, as measured on the date of vesting, of shares vested during the years ended December 31, 2019 , 2018 , and 2017 was $8.7 million , $6.7 million , and $6.5 million , respectively. Share Options: Option awards are generally granted with an exercise price equal to the market price of the Company’s stock at the date of grant; those option awards generally vest based on three years of continual service and are exercisable for a five -year period after vesting. Option awards granted have a 10 -year maximum term. The fair value of each option award is estimated on the date of grant using the Black-Scholes option valuation model. The fair value of all options is amortized on a straight-line basis over the requisite service periods, which are generally the vesting periods. The expected life of options granted represents the period of time that they are expected to be outstanding. The expected life is determined based on historical experience with similar awards, giving consideration to the contractual terms and vesting schedules. Expected volatilities of our common stock are estimated at the date of grant based on the historical volatility of the stock. The volatility factor is based on historical stock prices over the most recent period commensurate with the estimated expected life of the award. The risk-free interest rate is based on the U.S. Treasury curve in effect at the time of the award. The expected dividend yield is based on dividend trends and the market value of the Company’s stock price at the time of the award. A summary of option activity under the Plan as of December 31, 2019 , and changes during the year then ended is presented below: Shares Weighted Weighted Aggregate Balance at December 31, 2018 5,514 $ 9.91 Expired (1,187 ) 9.91 Exercised (4,327 ) 9.91 Balance at December 31, 2019 — $ — 0 $ — The total intrinsic value of options exercised during the years ended December 31, 2019 , 2018 , and 2017 was $108 thousand , $29 thousand , and $67 thousand , respectively. There were no options granted during the years ended December 31, 2019 , 2018 , and 2017 . There were no options that vested during the years ended December 2019 , 2018 , and 2017 . It is the Company’s policy to issue new shares for share option exercises and share awards. The Company expenses awards of share options and shares on a straight-line basis over the related vesting term of the award. For the years ended December 31, 2019 , 2018 and 2017 , the Company recognized pre-tax share-based compensation expense of $9.3 million , $8.4 million and $7.7 million , respectively.

Income Tax

Income Tax	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Income Tax	Income Tax The components of income tax expense are as follows: Years Ended December 31, 2019 2018 2017 (in thousands) Current expense Federal $ 40,471 $ 33,400 $ 39,708 State 6,359 5,446 3,016 Total current tax expense $ 46,830 $ 38,846 $ 42,724 Deferred tax expense (benefit) Federal $ 60 $ (291 ) $ 21,524 State 270 399 907 Total deferred tax expense 330 108 22,431 Total $ 47,160 $ 38,954 $ 65,155 Significant components of the Company’s deferred tax assets and liabilities are as follows: December 31, 2019 2018 (in thousands) Deferred tax assets: ALLL $ 20,489 $ 20,578 Lease liability 14,776 — Deferred compensation 11,079 9,501 Stock options and restricted stock 2,016 1,850 OREO — 288 Nonaccrual interest 112 446 Unrealized loss on investment securities — 10,129 Net operating losses and credit carryforwards 4,136 5,356 Other 245 733 Total deferred tax assets 52,853 48,881 Deferred tax liabilities: Asset purchase tax basis difference (7,888 ) (7,229 ) Right of use asset (13,415 ) — FHLB stock dividends (789 ) (790 ) Deferred loan fees (4,097 ) (4,399 ) Unrealized gain on investment securities (10,091 ) — Purchase accounting (8,946 ) (9,245 ) Depreciation (3,152 ) (2,609 ) Cash flow hedge (3,452 ) — Other (100 ) (195 ) Total deferred tax liabilities (51,930 ) (24,467 ) Net deferred tax asset $ 923 $ 24,414 A reconciliation of the Company’s effective income tax rate with the federal statutory tax rate is as follows: Years Ended December 31, 2019 2018 2017 Amount Percent Amount Percent Amount Percent (dollars in thousands) Income tax based on statutory rate $ 50,738 21 % $ 44,485 21 % $ 62,262 35 % Increase (decrease) resulting from: Tax exempt instruments (6,771 ) (3 )% (6,423 ) (3 )% (8,485 ) (5 )% Bank owned life insurance (1,963 ) (1 )% (1,261 ) (1 )% (3,351 ) (2 )% Acquisition costs — — % — — % 825 1 % Deferred tax asset revaluation — — % — — % 12,210 7 % State income tax, net of federal benefit 5,134 2 % 4,931 2 % 2,550 1 % Other, net 22 1 % (2,778 ) (1 )% (856 ) — % Income tax provision $ 47,160 20 % $ 38,954 18 % $ 65,155 37 % As of December 31, 2019 and 2018 , we had no unrecognized tax benefits. Our policy is to recognize interest and penalties on unrecognized tax benefits in “Provision for income taxes” in the Consolidated Statements of Income. There were no amounts related to interest and penalties recognized for the years ended December 31, 2019 and 2018 . As a result of recent acquisitions, the Company has net operating loss carryforwards in the federal, Idaho and Oregon jurisdictions of $15.8 million , $14.3 million and $121 thousand , respectively, which begin to expire in 2024. The Tax Cuts and Jobs Act was signed into law on December 22, 2017. The law included significant changes to the U.S. corporate tax system, including a Federal corporate rate reduction from 35% to 21% . In 2017, the Company applied the newly enacted corporate federal income tax rate of 21% resulting in a $12.2 million increase in tax expense from the re-measurement of its net deferred tax assets.

Regulatory Capital Requirements

Regulatory Capital Requirements	12 Months Ended
	Dec. 31, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Regulatory Capital Requirements	Regulatory Capital Requirements The Company (on a consolidated basis) and its banking subsidiary are subject to various regulatory capital requirements administered by the federal banking agencies. Failure to meet minimum capital requirements can initiate certain mandatory and possibly additional discretionary actions by regulators that, if undertaken, could have a direct material effect on the Company and its banking subsidiary’s financial statements. Under capital adequacy guidelines and the regulatory framework for prompt corrective action, the Company and its banking subsidiary must meet specific capital guidelines that involve quantitative measures of assets, liabilities, and certain off-balance sheet items as calculated under regulatory accounting practices. The capital amounts and classification are also subject to qualitative judgments by the regulators about components, risk weightings, and other factors. Prompt corrective action provisions are not applicable to bank holding companies. Basel III capital requirements became effective on January 1, 2015. The capital requirements, among other things (i) specify that Tier 1 capital consists of CET1, and “Additional Tier 1 capital” instruments meeting specified requirements, (ii) define CET1 narrowly by requiring that most deductions/adjustments to regulatory capital measures be made to CET1 and not to the other components of capital and (iii) expand the scope of the deductions/adjustments to capital as compared to existing regulations. Under the requirements that are now effective, the minimum capital ratios are (i) 4.5% CET1 to risk-weighted assets, (ii) 6% Tier 1 capital to risk-weighted assets, (iii) 8% total capital to risk-weighted assets and (iv) 4% Tier 1 capital to average total assets (Tier 1 leverage). The Company and the Bank have made the one-time election to opt-out of including accumulated other comprehensive income items in regulatory capital calculations. The Capital Rules also require a capital conservation buffer designed to absorb losses during periods of economic stress. The capital conservation buffer is composed entirely of CET1, on top of these minimum risk-weighted asset ratios. In addition, the Capital Rules provide for a countercyclical capital buffer applicable only to certain covered institutions. We do not expect the countercyclical capital buffer to be applicable to us or the Bank. Banking institutions with a ratio of CET1 to risk-weighted assets above the minimum but below the capital conservation buffer (or below the combined capital conservation buffer and countercyclical capital buffer, when the latter is applied) will face constraints on dividends, equity repurchases and compensation based on the amount of the shortfall. The implementation of the capital conservation buffer began on January 1, 2016 at the 0.625% level and was fully phased in over a three-year period (increasing by 0.625% on each subsequent January 1, until it reached 2.5% on January 1, 2019). As a result, the Company and the Bank are now required to maintain such additional capital conservation buffer of 2.5% of CET1, effectively resulting in minimum ratios of (i) 7% CET1 to risk-weighted assets, (ii) 8.5% Tier 1 capital to risk-weighted assets, and (iii) 10.5% total capital to risk-weighted assets. At December 31, 2019 , the capital conservation buffer for the Company and the Bank was 5.60% and 5.29% , respectively. As of December 31, 2019 , we and the Bank met all capital adequacy requirements under the Capital Rules. FDIC regulations set forth the qualifications necessary for a bank to be classified as “well-capitalized,” primarily for assignment of FDIC insurance premium rates. To qualify as “well-capitalized,” banks must have a CET1 risk-adjusted capital ratio of 6.5%, a Tier I risk-adjusted capital ratio of at least 8%, a total risk-adjusted capital ratio of at least 10% and a leverage ratio of at least 5%. Failure to qualify as “well-capitalized” can negatively impact a bank’s ability to expand and to engage in certain activities. As of December 31, 2019 , the most recent notification from the FDIC categorized Columbia Bank as well-capitalized under the regulatory framework for prompt corrective action. To be categorized as well- capitalized, an institution must maintain minimum CET1 risk-based, Tier 1 risk-based, total risk-based and Tier 1 leverage ratios as set forth in the following table. There are no conditions or events since the notification that management believes have changed Columbia Bank’s category. The Company and its banking subsidiary’s actual capital amounts and ratios as of December 31, 2019 and 2018 are presented in the following table: Actual Minimum Required Minimum Required Minimum Required To Be Well Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) December 31, 2019 CET1 Capital (to risk-weighted assets): The Company $ 1,317,202 12.45 % $ 476,260 4.50 % N/A N/A $ 740,849 7.00 % N/A N/A Columbia Bank $ 1,318,044 12.46 % $ 475,913 4.50 % N/A N/A $ 740,310 7.00 % $ 687,430 6.50 % Tier 1 Capital (to risk-weighted assets): The Company $ 1,317,202 12.45 % $ 635,014 6.00 % N/A N/A $ 899,603 8.50 % N/A N/A Columbia Bank $ 1,318,044 12.46 % $ 634,551 6.00 % N/A N/A $ 898,947 8.50 % $ 846,068 8.00 % Total Capital (to risk-weighted assets): The Company $ 1,439,877 13.60 % $ 846,685 8.00 % N/A N/A $ 1,111,274 10.50 % N/A N/A Columbia Bank $ 1,405,422 13.29 % $ 846,068 8.00 % N/A N/A $ 1,110,464 10.50 % $ 1,057,585 10.00 % Tier 1 Capital Leverage (to average assets): The Company $ 1,317,202 10.17 % $ 517,938 4.00 % N/A N/A $ 517,938 4.00 % N/A N/A Columbia Bank $ 1,318,044 10.22 % $ 515,797 4.00 % N/A N/A $ 515,797 4.00 % $ 644,746 5.00 % December 31, 2018 CET1 Capital (to risk-weighted assets): The Company $ 1,253,394 12.74 % $ 442,717 4.50 % $ 627,182 6.38 % $ 688,670 7.00 % N/A N/A Columbia Bank $ 1,274,317 12.96 % $ 442,552 4.50 % $ 626,948 6.38 % $ 688,414 7.00 % $ 639,241 6.50 % Tier 1 Capital (to risk-weighted assets): The Company $ 1,253,394 12.74 % $ 590,289 6.00 % $ 774,754 7.88 % $ 836,243 8.50 % N/A N/A Columbia Bank $ 1,274,317 12.96 % $ 590,069 6.00 % $ 774,465 7.88 % $ 835,931 8.50 % $ 786,759 8.00 % Total Capital (to risk-weighted assets): The Company $ 1,376,555 13.99 % $ 787,052 8.00 % $ 971,517 9.88 % $ 1,033,006 10.50 % N/A N/A Columbia Bank $ 1,362,016 13.85 % $ 786,759 8.00 % $ 971,155 9.88 % $ 1,032,621 10.50 % $ 983,448 10.00 % Tier 1 Capital Leverage (to average assets): The Company $ 1,253,394 10.24 % $ 489,399 4.00 % $ 489,399 4.00 % $ 489,399 4.00 % N/A N/A Columbia Bank $ 1,274,317 10.42 % $ 489,254 4.00 % $ 489,254 4.00 % $ 489,254 4.00 % $ 611,567 5.00 %

Parent Company Financial Inform

Parent Company Financial Information	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Parent Company Financial Information	Parent Company Financial Information Condensed Balance Sheets—Parent Company Only December 31, 2019 2018 (in thousands) Assets Cash $ 6,088 $ 945 Interest-earning deposits 21,717 7,226 Total cash and cash equivalents 27,805 8,171 Investment in banking subsidiary 2,156,039 2,049,855 Investment in other subsidiaries 5,671 5,312 Goodwill 4,729 4,729 Other assets 1,675 1,595 Total assets $ 2,195,919 $ 2,069,662 Liabilities and Shareholders’ Equity Subordinated debentures $ 35,277 $ 35,462 Other liabilities 680 551 Total liabilities 35,957 36,013 Shareholders’ equity 2,159,962 2,033,649 Total liabilities and shareholders’ equity $ 2,195,919 $ 2,069,662 Condensed Statements of Income—Parent Company Only Years Ended December 31, 2019 2018 2017 (in thousands) Income Dividend from banking subsidiary $ 168,000 $ 85,250 $ 66,800 Interest-earning deposits 100 12 2 Other income 68 56 8 Total income 168,168 85,318 66,810 Expense Compensation and employee benefits 791 978 732 Subordinated debentures interest expense 1,871 1,871 304 Other borrowings interest expense — 4 60 Other expense 2,111 2,058 3,090 Total expenses 4,773 4,911 4,186 Income before income tax benefit and equity in undistributed earnings of subsidiaries 163,395 80,407 62,624 Income tax benefit (967 ) (1,017 ) (548 ) Income before equity in undistributed earnings of subsidiaries 164,362 81,424 63,172 Equity in undistributed earnings of subsidiaries 30,089 91,458 49,656 Net income $ 194,451 $ 172,882 $ 112,828 Condensed Statements of Cash Flows—Parent Company Only Years Ended December 31, 2019 2018 2017 (in thousands) Operating Activities Net income $ 194,451 $ 172,882 $ 112,828 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed earnings of subsidiaries (30,089 ) (91,458 ) (49,656 ) Stock-based compensation expense 9,271 8,354 7,745 Net changes in other assets and liabilities (133 ) 1,622 1,672 Net cash provided by operating activities 173,500 91,400 72,589 Investing Activities Net cash paid in business combinations — — (580 ) Net cash used in investing activities — — (580 ) Financing Activities Common stock dividends (102,265 ) (83,459 ) (51,308 ) Repayment of junior subordinated debentures — (8,248 ) (6,186 ) Cash settlement of acquired equity awards — — (7,345 ) Purchase and retirement of common stock (2,792 ) (2,677 ) (2,299 ) Purchase of treasury shares (50,834 ) — — Proceeds from exercise of stock options 2,025 1,857 1,980 Net cash used in financing activities (153,866 ) (92,527 ) (65,158 ) Increase (decrease) in cash and cash equivalents 19,634 (1,127 ) 6,851 Cash and cash equivalents at beginning of year 8,171 9,298 2,447 Cash and cash equivalents at end of year $ 27,805 $ 8,171 $ 9,298 Supplemental disclosure of noncash investing and financing activities Share-based consideration issued in business combinations $ — $ — $ 636,385

Summary Of Quarterly Financial

Summary Of Quarterly Financial Information (Unaudited)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Summary of Quarterly Financial Information (Unaudited)	Summary of Quarterly Financial Information (Unaudited) Quarterly financial information for the years ended December 31, 2019 and 2018 is summarized as follows: Fourth Third Second First Year Ended (in thousands, except per share amounts) 2019 Total interest income $ 133,109 $ 132,533 $ 135,422 $ 128,888 $ 529,952 Total interest expense 8,292 10,083 10,306 7,866 36,547 Net interest income 124,817 122,450 125,116 121,022 493,405 Provision for loan and lease losses 1,614 299 218 1,362 3,493 Noninterest income 21,807 28,030 25,648 21,696 97,181 Noninterest expense 86,978 87,076 86,728 84,700 345,482 Income before income taxes 58,032 63,105 63,818 56,656 241,611 Provision for income taxes 11,903 12,378 12,094 10,785 47,160 Net income $ 46,129 $ 50,727 $ 51,724 $ 45,871 $ 194,451 Per common share (1) Earnings (basic) $ 0.64 $ 0.70 $ 0.71 $ 0.63 $ 2.68 Earnings (diluted) $ 0.64 $ 0.70 $ 0.71 $ 0.63 $ 2.68 2018 Total interest income $ 129,801 $ 127,575 $ 120,549 $ 119,144 $ 497,069 Total interest expense 5,913 4,779 3,875 3,663 18,230 Net interest income 123,888 122,796 116,674 115,481 478,839 Provision for loan and lease losses 1,789 3,153 3,975 5,852 14,769 Noninterest income 20,402 21,019 23,692 23,143 88,256 Noninterest expense 87,019 82,841 84,643 85,987 340,490 Income before income taxes 55,482 57,821 51,748 46,785 211,836 Provision for income taxes 10,734 11,406 9,999 6,815 38,954 Net income $ 44,748 $ 46,415 $ 41,749 $ 39,970 $ 172,882 Per common share (1) Earnings (basic) $ 0.61 $ 0.63 $ 0.57 $ 0.55 $ 2.36 Earnings (diluted) $ 0.61 $ 0.63 $ 0.57 $ 0.55 $ 2.36 __________ (1) Due to averaging of shares, quarterly EPS may not add up to the totals reported for the full year.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	Revenue from Contracts with Customers Revenue in the scope of Topic 606, Revenue from Contracts with Customers is measured based on the consideration specified in the contract with a customer and excludes amounts collected on behalf of third parties. The vast majority of the Company’s revenue is specifically outside the scope of Topic 606. For in-scope revenue, the following is a description of principal activities, separated by the timing of revenue recognition from which the Company generates its revenue from contracts with customers. a. Revenue earned at a point in time - Examples of revenue earned at a point in time are ATM transaction fees, wire transfer fees, overdraft fees, interchange fees and foreign exchange transaction fees. Revenue is primarily based on the number and type of transactions and is generally derived from transactional information accumulated by our systems and is recognized immediately as the transactions occur or upon providing the service to complete the customer’s transaction. The Company is the principal in each of these contracts, with the exception of interchange fees, in which case we are acting as the agent and record revenue net of expenses paid to the principal. b. Revenue earned over time - The Company earns revenue from contracts with customers in a variety of ways where the revenue is earned over a period of time - generally monthly. Examples of this type of revenue are deposit account maintenance fees, investment advisory fees, merchant revenue and safe deposit box fees. Revenue is generally derived from transactional information accumulated by our systems or those of third-parties and is recognized as the related transactions occur or services are rendered to the customer. The Company recognizes revenue from contracts with customers when it satisfies its performance obligations. The Company’s performance obligations are typically satisfied as services are rendered and our contracts generally do not include multiple performance obligations. As a result, there are no contract balances as payments and services are rendered simultaneously. Payment is generally collected at the time services are rendered, monthly or quarterly. Unsatisfied performance obligations at the report date are not material to our consolidated financial statements. In certain cases, other parties are involved with providing products and services to our customers. If the Company is principal in the transaction (providing goods or services itself), revenues are reported based on the gross consideration received from the customer and any related expenses are reported gross in noninterest expense. If the Company is an agent in the transaction (arranging for another party to provide goods or services), the Company reports its net fee or commission retained as revenue. Rebates, waivers and reversals are recorded as a reduction of the transaction price either when the revenue is recognized by the Company or at the time the rebate, waiver or reversal is earned by the customer. Practical expedients The Company applies the practical expedient in paragraph 606-10-32-18 and does not adjust the consideration from customers for the effects of a significant financing component if at contract inception the period between when the entity transfers the goods or services and when the customer pays for that good or service will be one year or less. The Company pays sales commissions to its employees in accordance with certain incentive plans and in connection with obtaining certain contracts with customers. The Company applies the practical expedient in paragraph 340-40-25-4 and expenses such sales commissions when incurred if the amortization period of the asset the Company otherwise would have recognized is one year or less. Sales commissions are included in compensation and employee benefits expense. For the Company’s contracts that have an original expected duration of one year or less, the Company uses the practical expedient in paragraph 606-10-50-14 and has not disclosed the amount of the transaction price allocated to unsatisfied performance obligations as of the end of each reporting period or when the Company expects to recognize this revenue. The following table shows the disaggregation of revenue from contracts with customers for the period indicated: Years Ended December 31, 2019 2018 (in thousands) Noninterest income: Revenue from contracts with customers: Deposit account and treasury management fees $ 35,695 $ 36,072 Card revenue 15,198 19,719 Financial services and trust revenue 12,799 12,135 Total revenue from contracts with customers 63,692 67,926 Other sources of noninterest income 33,489 20,330 Total noninterest income $ 97,181 $ 88,256

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	12 Months Ended
	Dec. 31, 2019
Accounting Policies [Line Items]
Consolidation	Consolidation The Consolidated Financial Statements of the Company include the accounts of the Corporation and its subsidiaries, including the Bank and Columbia Trust. Intercompany balances and transactions have been eliminated in consolidation.
Cash and cash equivalents	Cash and cash equivalents Cash and cash equivalents include cash and due from banks, and interest-bearing balances due from correspondent banks and the FRB. Cash equivalents have a maturity of 90 days or less at the time of purchase.
Securities	Securities Securities are classified based on management’s intention on the date of purchase. All securities are classified as available for sale and are presented at fair value. Unrealized gains or losses on securities available for sale are excluded from net income but are included as separate components of other comprehensive income, net of taxes. Purchase premiums or discounts on securities available for sale are amortized or accreted into income using the interest method over the terms of the individual securities. The Company performs a quarterly assessment to determine whether a decline in fair value below amortized cost is other-than-temporary. Amortized cost includes adjustments made to the cost of an investment for accretion, amortization, collection of cash and previous other-than-temporary impairment recognized in earnings. Other-than-temporary impairment exists when it is more likely than not that the Company will be unable to recover the entire amortized cost basis of the security. In performing the quarterly assessment for debt securities, management considers whether or not the Company expects to recover the entire amortized cost basis of the security. In addition, management also considers whether it is more likely than not that it will not have to sell the security before recovery of its cost basis. If the Company intends to sell a security or it is more likely than not it will be required to sell a security prior to recovery of its cost basis, the entire amount of impairment is recognized in earnings. If the Company does not intend to sell the security or it is not more likely than not it will be required to sell the security prior to recovery of its cost basis, the credit loss component of impairment is recognized in earnings and impairment associated with non-credit factors, such as market liquidity, is recognized in “Other comprehensive income (loss), net of tax.” A credit loss is the difference between the cost basis of the security and the present value of cash flows expected to be collected, discounted at the security’s effective interest rate at the date of acquisition. The cost basis of an other-than-temporarily impaired security is written down by the amount of impairment recognized in earnings. The new cost basis is not adjusted for subsequent recoveries in fair value. However, the difference between the new amortized cost basis and the cash flows expected to be collected is accreted as interest income. The total other-than-temporary impairment, if any, is presented in the Consolidated Statements of Income with a reduction for the amount of other-than-temporary impairment that is recognized in “Other Comprehensive Income,” if any. Realized gains or losses on sales of securities available for sale are recorded using the specific identification method.
Federal Home Loan Bank Stock	Federal Home Loan Bank Stock The Company holds shares of Class B stock issued by the FHLB, which has been designated as FHLB membership stock or FHLB activity based stock in accordance with the capital plan of the FHLB. Membership stock is stock we are required to purchase and hold as a condition of membership in the FHLB. The Company’s membership stock purchase requirement is measured as a percentage of our year end assets, subject to a $10 million cap. Class B stock may be redeemed, subject to certain limitations, on five years’ written notice to the FHLB. Activity based stock is stock we are required to purchase and hold in order to obtain an advance or participate in FHLB mortgage programs. The Company’s activity based stock purchase requirement is measured as a percentage of our advance proceeds. Our FHLB stock is carried at par value because the shares are issued, transferred, redeemed, and repurchased by the FHLB at a par value of $100 . The FHLB stock is subject to recoverability testing per the Financial Services-Depository and Lending topic of the FASB ASC.
Loans held for sale	Loans held for sale Mortgage loans held for sale are carried at the lower of amortized cost or fair value. Due to the short period of time between the origination and sale, the carrying amount of loans held for sale approximates the fair values.
Loans	Loans Loans, excluding PCI loans, are generally carried at the unpaid principal balance, net of purchase premiums, purchase discounts and net deferred loan fees. Net deferred loan fees include nonrefundable loan origination fees less direct loan origination costs. Net deferred loan fees, purchase premiums and purchase discounts are amortized into interest income using either the interest method or straight-line method over the terms of the loans, adjusted for actual prepayments. The interest method is used for all loans except revolving loans, for which the straight-line method is used. Interest income is accrued as earned. Fees related to lending activities, other than the origination or purchase of loans, are recognized as noninterest income during the period the related services are performed. Nonaccrual loans —Loans are placed on nonaccrual status when a loan becomes contractually past due 90 days with respect to interest or principal unless the loan is both well secured and in the process of collection, or if full collection of interest or principal becomes uncertain. When a loan is placed on nonaccrual status, any accrued and unpaid interest receivable is reversed and the amortization of net deferred loan fees, premiums and discounts ceases. The interest payments received on nonaccrual loans are generally accounted for on the cost-recovery method whereby the interest payment is applied to the principal balances. Loans may be returned to accrual status when improvements in credit quality eliminate the doubt as to the full collectability of both interest and principal and a period of sustained performance has occurred. Impaired loans —Loans are considered impaired when based on current information and events, it is probable that the Company will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a TDR. The assessment for impairment occurs when and while such loans are designated as classified per the Company’s internal risk rating system or when and while such loans are on nonaccrual. All nonaccrual loans greater than $500,000 and all TDR loans are considered impaired and analyzed individually on a quarterly basis. Classified loans with an outstanding balance greater than $500,000 are evaluated for potential impairment on a quarterly basis. Restructured Loans —A loan is classified as a TDR when a borrower is experiencing financial difficulties that lead to a restructuring of the loan, and the Company grants concessions to the borrower in the restructuring that it would not otherwise consider. These concessions may include interest rate reductions, principal forgiveness, extension of maturity date and other actions intended to minimize potential losses. Generally, a nonaccrual loan that is restructured remains on nonaccrual status for a period of six months to demonstrate that the borrower can meet the restructured terms. If the borrower’s performance under the new terms is not reasonably assured, the loan remains classified as a nonaccrual loan. Purchased Credit Impaired Loans —Loans acquired with evidence of credit deterioration since origination for which it is probable that all contractually required payments will not be collected are accounted for under ASC 310-30, Loans and Debt Securities Acquired with Deteriorated Credit Quality . In addition, because of the significant discounts associated with certain of the acquired loan portfolios, the Company elected to account for those certain acquired loans under ASC 310-30. In situations where such loans have similar risk characteristics, loans are aggregated into pools to estimate cash flows. A pool is accounted for as a single asset with a single interest rate, cumulative loss rate and cash flow expectation. Expected cash flows at the acquisition date in excess of the fair value of loans are considered to be accretable yield, which is recognized as interest income over the life of the loan pool using a level yield method if the timing and amount of the future cash flows of the pool is reasonably estimable. Subsequent to the acquisition date, any increases in cash flow over those expected at purchase date in excess of fair value are recorded as interest income prospectively. Any subsequent decreases in cash flow over those expected at purchase date due to credit deterioration are recognized by recording an ALLL on PCI loans. Any disposals of loans, including sales of loans, payments in full or foreclosures result in the removal of the loan from the loan pool at the carrying amount. Unfunded loan commitments —Unfunded commitments are generally related to providing credit facilities to clients of the Bank and are not actively traded financial instruments. These unfunded commitments are disclosed as financial instruments with off-balance sheet risk in Note 18, “Commitments and Contingent Liabilities.”
Allowance for Loan and Lease Losses	Allowance for Loan and Lease Losses The ALLL is an accounting estimate of incurred credit losses in our loan portfolio at the balance sheet date. The provision for loan and lease losses is the expense recognized in the Consolidated Statements of Income to adjust the allowance to the levels deemed appropriate by management, as measured by the Company’s credit loss estimation methodologies. Loans Collectively Evaluated for Impairment —This measure of estimated credit losses is based upon the loss experience over a historical base period adjusted for a loss emergence period. The loss emergence period is an estimate of the period that it takes, on average, for us to identify the amount of loss incurred for a loan that has suffered a loss-causing event. Management then considers the effects of the following qualitative factors to ensure our allowance reflects the inherent losses in the loan portfolio: • Economic and business conditions; • Concentration of credit; • Lending management and staff; • Lending policies and procedures; • Loss and recovery trends; • Nature and volume of the portfolio; • Trends in problem loans, loan delinquencies and nonaccrual loans; • Quality of internal loan review; and • External factors. These qualitative factors have a high degree of subjectivity and changes in any of the factors could have a significant impact on our calculation of the allowance. The qualitative adjustment by loan segment is based upon management's assessment of inherent losses within a range between the weighted historical loss factor by segment and the maximum consecutive quarterly losses in the relevant loss emergence period by segment over the historical base period. Loan and lease losses are charged against the allowance when management believes the collectability of a loan balance is unlikely. Subsequent recoveries, if any, are credited to the allowance. Loans Individually Evaluated for Impairment —This measure of estimated credit losses begins if, based upon current information and events, we believe it is probable that we will be unable to collect all amounts due according to the contractual terms of the loan agreement or when a loan has been modified in a TDR. When a loan has been identified as impaired, the amount of impairment will be measured using discounted cash flows, except when it is determined that the remaining source of repayment for the loan is the operation or liquidation of the underlying collateral. In these cases, the current fair value of the collateral, reduced by costs to sell, will be used in place of discounted cash flows. As a final alternative, the observable market price of the loan may be used to assess impairment. The Company predominately uses the fair value of collateral approach based upon a reliable valuation. When the measurement of the impaired loan is less than the recorded amount of the loan, an impairment is recognized by recording a charge-off to the allowance or by designating a specific reserve. Purchased Credit Impaired Loans —The Company updates its cash flow projections for PCI loans accounted for under ASC 310-30 on a quarterly basis. Assumptions utilized in this process include projections related to probability of default, loss severity, prepayment and recovery lag. Projections related to probability of default and prepayment are calculated utilizing a loan migration analysis. The loan migration analysis is a matrix of probability that is used to estimate the probability of a loan pool transitioning into a particular delinquency state given its delinquency state at the re-measurement date. Loss severity factors are based upon either actual charge-off data within the loan pools or industry averages, and recovery lags are based upon the collateral within the loan pools.
Allowance for Unfunded Commitments and Letters of Credit	Unfunded Commitments and Letters of Credit —The allowance for unfunded commitments is maintained at a level believed by management to be sufficient to absorb estimated probable losses related to these unfunded credit facilities. The determination of the adequacy of the allowance is based on periodic evaluations of the unfunded credit facilities including an assessment of the probability of commitment usage, credit risk factors for loans outstanding to these same customers, and the terms and expiration dates of the unfunded credit facilities. The allowance for unfunded commitments is included in “Other liabilities” on the Consolidated Balance Sheets, with changes to the balance charged against noninterest expense.
Allowance for Credit Losses, Policy for Uncollectible Amounts	Adoption of Allowance for Credit Losses - ASC 326 In accordance with ASU 2016-13, the Company was required to adopt ASC 326 as of January 1, 2020. The allowance for credit losses under ASC 326 is an accounting estimate of expected losses over the contractual life of assets carried at amortized cost within the Company’s loan portfolio at the balance sheet date. The ASU requires a financial asset (or group of financial assets) measured at amortized cost to be presented at the net amount expected to be collected. The allowance for credit losses is a valuation account that is deducted from the amortized cost basis of the financial asset to present the net carrying value at the amount expected to be collected on the financial asset. The quantitative allowance is calculated using a discounted cash flow approach with a probability of default methodology. The probability of default is an assumption derived from regression models which determines the relationship between historical defaults and certain economic variables. The Company determines a reasonable and supportable forecast and applies that forecast to the model to determine defaults over the forecast period. Following the forecast period, the economic variables used to calculate the probability of default revert to a historical average. Other assumptions relevant to the discounted cash flow model to derive the quantitative allowance include the loss given default, which is the estimate of loss for a defaulted loan, and the discount rate applied to future cash flows. The model calculates the net present value of each loan using both the contractual and expected cash flows, respectively. In addition to the quantitative portion of the allowance for credit losses, the Company also considers the effects of the following qualitative factors in its calculation of expected losses in the loan portfolio: • Economic and business conditions; • Concentration of credit; • Lending management and staff; • Lending policies and procedures; • Loss and recovery trends; • Nature and volume of the portfolio; • Trends in problem loans, loan delinquencies and nonaccrual loans; • Quality of internal loan review; and • External factors. These qualitative factors are based in quantitative factors but also include a high degree of subjectivity and changes in any of the factors could have a significant impact on our calculation of the allowance. Loans for which repayment is expected to be provided substantially through the operation or sale of collateral are considered collateral-dependent. The allowance for credit losses for collateral-dependent loans is measured on the basis of the fair value of the collateral when foreclosure is probable.
Premises and Equipment	Premises and Equipment Land, buildings, leasehold improvements and equipment are stated at cost less accumulated depreciation and amortization. Gains or losses on dispositions are reflected in current operations. Expenditures for improvements and major renewals are capitalized, and ordinary maintenance, repairs and small purchases are charged to “Occupancy” expense in the Consolidated Statements of Income. Depreciation and amortization are computed based on the straight-line method over the estimated useful lives of the various classes of assets. The ranges of useful lives for the principal classes of assets are as follows: Buildings and building improvements 5 to 39 years Leasehold improvements Term of lease or useful life, whichever is shorter Furniture, fixtures and equipment 3 to 7 years Vehicles 5 years Computer software 3 to 5 years
Software	Software Capitalized software is stated at cost, less accumulated amortization. Amortization is computed on a straight-line basis and charged to expense over the estimated useful life of the software, which is generally three years. Capitalized software is included in “Premises and equipment, net” in the Consolidated Balance Sheets.
Implementation Costs in a Cloud Computing Arrangement	Implementation Costs in a Cloud Computing Arrangement Implementation costs incurred in a hosting arrangement that is a service contract are capitalized based on criteria in ASC 350-40. The capitalized costs are expensed over the term of the hosting arrangement. Capitalized implementation costs in a cloud computing arrangement are included in “Other assets” in the Consolidated Balance Sheets.
Other Real Estate Owned	Other Real Estate Owned OREO is composed of real estate acquired by the Company through either foreclosure or deed in lieu of foreclosure in satisfaction of debt. At acquisition, OREO is recorded at fair value less estimated costs to sell. Any fair value adjustments at acquisition are charged to the allowance, or in the event of a write-up without previous losses charged to the allowance, a credit to earnings is recorded. The fair value of the OREO is based upon a current appraisal or a letter of intent to purchase. Losses that result from the ongoing periodic valuation of these properties are charged to the net cost of operation of OREO in the period in which they are identified. Improvements to OREO are capitalized and holding costs are charged to the net cost of operation of OREO as incurred.
Goodwill and Intangibles	Goodwill and Intangibles Net assets of companies acquired in a business combination are recorded at fair value at the date of acquisition. Any excess of the purchase price over the fair value of net assets acquired, including identified intangible assets, is recognized as goodwill. Goodwill is reviewed for potential impairment annually, during the third quarter, or, more frequently, if events or circumstances indicate a potential impairment, at the reporting unit level. A reporting unit is an operating segment or one level below an operating segment for which discrete financial information is available and regularly reviewed by management. The Company consists of a single reporting unit. If the fair value of the reporting unit, including goodwill, is determined to be less than the carrying amount of the reporting unit, a further test is required to measure the amount of impairment. If an impairment loss exists, the carrying amount of goodwill is adjusted to a new cost basis. Subsequent reversal of a previously recognized goodwill impairment loss is prohibited. Identified intangible assets are amortized on an accelerated basis over the period benefited. Intangible assets are also evaluated for impairment if events and circumstances indicate a possible impairment. Such evaluation is based on undiscounted cash flow projections. At December 31, 2019 , intangible assets included in the Consolidated Balance Sheets principally consisted of CDI with an original estimated life of 10 years .
Leases	Leases The Company determines if a lease is present at the inception of an agreement. Operating leases are capitalized at commencement and are discounted using the Company’s FHLB borrowing rate for a similar term borrowing unless the lease defines an implicit rate within the contract. Leases with original terms of less than 12 months are not capitalized. For operating leases existing prior to January 1, 2019, the rate for the remaining lease term as of January 1, 2019 was used. Right-of-use assets represent the Company’s right to use an underlying asset for the lease term and lease liabilities represent the obligation to make lease payments arising from the lease. Operating lease right-of-use assets and operating lease liabilities are recognized on the lease commencement date based on the present value of lease payments over the lease term. The lease term includes options to extend or terminate the lease if the Company is reasonably certain that an option will be exercised. Operating leases are included within “Other assets” in the Consolidated Balance Sheets. See Note 10, “Leases” for additional information on leases.
Income Taxes	Income Taxes The provision for income taxes includes current and deferred income tax expense on net income adjusted for temporary and permanent differences such as interest income from state and municipal securities and investments in affordable housing tax credits. Deferred tax assets and liabilities are recognized for the expected future tax consequences of existing temporary differences between the financial reporting and tax reporting basis of assets and liabilities using enacted tax laws and rates. The effect on deferred tax assets and liabilities of a change in tax rates is recognized in income in the period that includes the enactment date. On a quarterly basis, management evaluates deferred tax assets to determine if these tax benefits are expected to be realized in future periods. This determination is based on facts and circumstances, including the Company’s current and future tax outlook. To the extent a deferred tax asset is no longer considered “more likely than not” to be realized, a valuation allowance is established. We recognize the tax benefit from uncertain tax positions only if it is more likely than not that the tax positions will be sustained on examination by the tax authorities, based on the technical merits of the position. The tax benefit is measured based on the largest benefit that has a greater than 50% likelihood of being realized upon ultimate settlement. We recognize interest and penalties related to unrecognized tax benefits in “Provision for income taxes” in the Consolidated Statements of Income.
Advertising	Advertising Advertising costs are generally expensed as incurred.
Earnings per Common Share	Earnings per Common Share The Company’s capital structure includes common shares, restricted common share awards, common share options, and, during a portion of 2017, convertible preferred shares. Restricted common share awards participate in dividends declared on common shares at the same rate as common shares. Convertible preferred shares participated in dividends declared on common shares on an “as if converted” basis. Restricted common share awards and convertible preferred shares are considered participating securities under the EPS topic of the FASB ASC. The Company calculates EPS using the two-class method. The two-class method is an earnings allocation formula that treats a participating security as having rights to earnings that otherwise would have been available to common shareholders but does not require the presentation of basic and diluted EPS for securities other than common shares. Under the two-class method, basic EPS is computed by dividing earnings allocated to common shareholders by the weighted average number of common shares outstanding for the period. Earnings allocated to common shareholders represents net income reduced by earnings allocated to participating securities. Diluted EPS is computed in the same manner as basic EPS except that the denominator is increased to include the number of additional common shares that would have been outstanding if certain shares issuable upon exercise of common share options were included unless those additional shares would have been anti-dilutive. For the diluted EPS computation, the treasury stock method is applied and compared to the two-class method and whichever method results in a more dilutive impact is utilized to calculate diluted EPS.
Share-Based Payment	Share-Based Payment The Company accounts for stock options and stock awards in accordance with the Compensation—Stock Compensation topic of the FASB ASC. Authoritative guidance requires the Company to measure the cost of employee services received in exchange for an award of equity instruments, such as stock options or stock awards, based on the fair value of the award on the grant date. This cost must be recognized in the Consolidated Statements of Income over the vesting period of the award. The Company issues restricted common share awards which generally vest over a four-year period and have full voting rights. Pursuant to our new equity incentive plan approved in 2018, for any awards issued under the new plan, the holder accrues dividends, which are paid out when the shares vest. For any awards granted prior to the new plan, the holder receives dividends whether or not the shares have vested. Restricted stock is valued at the closing price of the Company’s stock on the date of an award.
Derivatives and Hedging Activities	Derivatives and Hedging Activities In accordance with the Derivatives and Hedging topic of the FASB ASC, the Company recognizes derivatives as assets or liabilities on the Consolidated Balance Sheets at their fair value. The Company periodically enters into interest rate contracts with customers and offsetting contracts with third parties. As these interest rate contracts are not designated as hedges under the Derivatives and Hedging topic of the FASB ASC, the changes in fair value of these instruments are recognized immediately in earnings. As part of the Company’s overall interest rate risk management, the Company uses an interest rate collar with a notional amount of $500.0 million to mitigate interest rate risk. This collar is designated and qualifies as a cash flow hedge. Gains and losses are recorded in accumulated other comprehensive income to the extent the hedge is effective. Gains and losses are reclassified from accumulated other comprehensive income to earnings in the period the hedged transaction affects earnings and are included in the same income statement line item that the hedged transaction is recorded.
Accounting Pronouncements Recently Adopted or Issued	Accounting Pronouncements Recently Adopted or Issued Accounting Standards Adopted in 2019 In February 2016, the FASB issued ASU 2016-02, Leases (Topic 842) . The amendments included in this ASU create a new accounting model for both lessees and lessors. The new guidance requires lessees to recognize lease liabilities, initially measured at the present value of future lease payments, and corresponding right-of-use assets for all leases with lease terms greater than 12 months. The new lease model differs from the old lease accounting model, as the old model does not require such lease liabilities and corresponding right-of-use assets to be recorded for operating leases. The amendments in ASU 2016-02 must be adopted using the modified retrospective approach and will be effective for the first interim or annual period beginning after December 15, 2018. The FASB subsequently issued ASU 2018-11, which allows for an additional (optional) transition method. The Company adopted the new standard effective January 1, 2019 utilizing the transition method allowed under ASU 2018-11 and did not restate comparative periods. The Company elected the package of practical expedients permitted under the transition guidance, which allowed us to carryforward our historical lease classifications and our assessment on whether a contract is or contains a lease. We also elected to keep leases with an initial term of 12 months or less off the balance sheet. The adoption of the new standard resulted in an increase in other assets and an increase in other liabilities of $49.2 million and $48.2 million , respectively. The Company recognized a cumulative effect adjustment of $782 thousand to increase the beginning balance of retained earnings related to previous deferred gains on sale-leaseback transactions. In August 2018, the FASB issued ASU 2018-15, Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40) - Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That is a Service Contract . The amendments in this ASU align the requirements for capitalizing implementation costs incurred in a hosting arrangement that is a service contract with the requirements for capitalizing implementation costs incurred to develop or obtain internal-use software. The amendments also require the entity to expense the capitalized implementation costs of a hosting arrangement that is a service contract over the term of the hosting arrangement, including reasonably certain renewal periods. The amendments in ASU 2018-15 are effective for fiscal years beginning after December 15, 2019 and interim periods within those fiscal years. Early adoption is permitted, including adoption in any interim period. The amendments can be adopted on a prospective or retrospective basis. The Company adopted the new standard effective July 1, 2019 on a prospective basis. The adoption of the new standard resulted in an increase in other assets of $1.5 million . Recently Issued Accounting Standards, Not Yet Adopted In December 2019, the FASB issued ASU 2019-12, Income Taxes (Topic 740) - Simplifying the Accounting for Income Taxes. The guidance issued in this update simplifies the accounting for income taxes by eliminating certain exceptions to the guidance in ASC 740 related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition for deferred tax liabilities for outside basis differences. This ASU also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The ASU is effective for interim and annual reporting periods beginning after December 15, 2020; early adoption is permitted. The adoption of this ASU is not expected to have a material impact on the Company’s consolidated financial statements. In April 2019, the FASB issued ASU 2019-04, Codification Improvements to Topic 326, Financial Instruments - Credit Losses, Topic 815, Derivatives and Hedging, and Topic 825, Financial Instruments . The amendments in this ASU clarify certain aspects of accounting for credit losses, hedging activities, and financial instruments (addressed by ASUs 2016-01, 2016-13, and 2017-12). Many of the amendments reflect decisions reached at FASB meetings or meetings of the Board’s credit losses transition resource group. Topics covered in this ASU include: accrued interest, transfers between classifications or categories for loans and debt securities, recoveries, reinsurance recoverables, projections of interest rate environments for variable-rate financial instruments, costs to sell when foreclosure is probable, consideration of expected prepayments when determining the effective interest rate, vintage disclosures, extension and renewal options, etc. In June 2016, the FASB issued ASU 2016-13, Financial Instruments – Credit Losses (Topic 326) - Measurement of Credit Losses on Financial Instruments . The amendments included in this ASU require an entity to reflect its current estimate of all expected credit losses for assets held at an amortized cost basis. For available for sale debt securities, credit losses will be measured in a manner similar to current GAAP, however, this ASU requires that credit losses be presented as an allowance rather than as a write-down. In November 2019, the FASB subsequently issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments - Credit Losses. The amendments in the Update require entities to include expected recoveries of the amortized cost basis previously written-off or expected to be written-off in the valuation account for purchased financial assets with credit deterioration. In addition, the amendments in this Update clarify and improve various aspects of the guidance for ASU 2016-13. Unlike the incurred loss models, the CECL model in ASU 2016-13 does not specify a threshold for the recognition of an impairment allowance. Rather, the Company recognizes an impairment allowance equal to its estimate of lifetime expected credit losses, adjusted for prepayments, for in-scope financial instruments. Accordingly, the impairment allowance measured under the CECL model may change significantly from the impairment allowance measured under the Company’s incurred loss model. The Company engaged a third-party vendor to assist in the CECL calculation and has developed and implemented an internal governance framework. The amendments in ASU 2016-13 and the above ASUs related to Credit Losses are effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. Early adoption was permitted, including adoption in any interim period. The Company adopted the new standards, using a modified retrospective approach, effective January 1, 2020, which resulted in an increase of $1.6 million to its allowance for credit losses, an increase of $1.6 million to its allowance for unfunded commitments and letters of credit and a net-of-tax cumulative-effect adjustment of $2.5 million to decrease the beginning balance of retained earnings. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement (Topic 820) - Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement. This ASU adds, eliminates and modifies certain disclosure requirements for fair value measurements. Among the changes, entities will no longer be required to disclose the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, but will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. The ASU is effective for interim and annual reporting periods beginning after December 15, 2019; early adoption is permitted. Entities are also allowed to elect early adoption of the eliminated or modified disclosure requirements and delay adoption of the added disclosure requirements until their effective date. The Company adopted the new standard effective January 1, 2020. As the ASU only revised disclosure requirements, adoption of this ASU did not have a material impact on the Company’s consolidated financial statements.

Business Combinations (Tables)

Business Combinations (Tables) - Pacific Continental [Member]	12 Months Ended
	Dec. 31, 2019
Business Acquisition [Line Items]
Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]	The table below summarizes the amounts recognized as of the acquisition date for each major class of assets acquired and liabilities assumed: November 1, 2017 (in thousands) Merger consideration $ 637,103 Identifiable net assets acquired, at fair value Assets acquired Cash and cash equivalents $ 81,190 Investment securities 449,291 FHLB stock 7,084 Loans 1,873,987 Interest receivable 7,827 Premises and equipment 27,343 OREO 10,279 CDI 46,875 Other assets 50,638 Total assets acquired 2,554,514 Liabilities assumed Deposits (2,118,982 ) FHLB advances (101,127 ) Subordinated debentures (35,678 ) Junior subordinated debentures (14,434 ) Securities sold under agreements to repurchase (1,617 ) Other liabilities (28,653 ) Total liabilities assumed (2,300,491 ) Total fair value of identifiable net assets 254,023 Goodwill $ 383,080
Business Acquisition, Pro Forma Information [Table Text Block]	For illustrative purposes only, the following table presents certain unaudited pro forma information for the year ended December 31, 2017 . This unaudited, estimated pro forma financial information was calculated as if Pacific Continental had been acquired as of the beginning of the year prior to the date of acquisition. This unaudited pro forma information combines the historical results of Pacific Continental with the Company’s consolidated historical results and includes certain adjustments reflecting the estimated impact of certain fair value adjustments for the respective periods. The pro forma information is not indicative of what would have occurred had the acquisition occurred as of the beginning of the year prior to the acquisition. In particular, no adjustments have been made to eliminate the impact of other-than-temporary impairment losses and losses recognized on the sale of securities that may not have been necessary had the investment securities been recorded at fair value as of the beginning of the year prior to the date of acquisition. The unaudited pro forma information does not consider any changes to the provision for credit losses resulting from recording loan assets at fair value. Additionally, Columbia expects to achieve further operating cost savings and other business synergies, including revenue growth as a result of the acquisition, which are not reflected in the pro forma amounts that follow. As a result, actual amounts would have differed from the unaudited pro forma information presented. Unaudited Pro Forma for the Year Ended December 31, 2017 (in thousands, except per share amounts) Total revenues (net interest income plus noninterest income) $ 571,944 Net income $ 149,859 EPS - basic $ 2.23 EPS - diluted $ 2.23
Business Acquisition, Integration, Restructuring and Other Related Costs [Text Block]	The following table shows the impact of the acquisition-related expenses related to the acquisition of Pacific Continental for the periods indicated to the various components of noninterest expense: Years ended December 31, 2019 2018 2017 (in thousands) Noninterest Expense Compensation and employee benefits $ — $ 3,620 $ 8,014 Occupancy — 1,619 1,912 Data processing — 963 1,555 Legal and professional fees — 1,028 4,618 Advertising and promotion — 537 467 Other — 894 630 Total impact of acquisition-related costs to noninterest expense $ — $ 8,661 $ 17,196

Securities (Tables)

Securities (Tables)	12 Months Ended
	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Securities Available for Sale	The following table summarizes the amortized cost, gross unrealized gains and losses and the resulting fair value of debt securities available for sale: Amortized Gross Gross Fair Value December 31, 2019 (in thousands) U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,864,949 $ 47,223 $ (19,222 ) $ 2,892,950 Other asset-backed securities (1) 194,563 2,476 (989 ) 196,050 State and municipal securities 478,366 10,660 (224 ) 488,802 U.S. government agency and government-sponsored enterprise securities 165,218 3,127 (5 ) 168,340 Total $ 3,703,096 $ 63,486 $ (20,440 ) $ 3,746,142 December 31, 2018 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,045,728 $ 8,473 $ (40,846 ) $ 2,013,355 Other asset-backed securities (1) 176,793 763 (2,621 ) 174,935 State and municipal securities 579,755 2,328 (7,760 ) 574,323 U.S. government agency and government-sponsored enterprise securities 408,088 1,235 (4,736 ) 404,587 U.S. government securities 251 — (3 ) 248 Total $ 3,210,615 $ 12,799 $ (55,966 ) $ 3,167,448 __________ (1) Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation.
Schedule of gross realized gains and losses on sales and calls of securities available for sale [Table Text Block]	The following table provides the proceeds and both gross realized gains and losses on the sales and calls of debt securities available for sale as well as other securities gains and losses for the periods indicated: Years Ended December 31, 2019 2018 2017 (in thousands) Proceeds from sales and calls of debt securities available for sale $ 259,554 $ 32,330 $ 30,403 Gross realized gains from sales of debt securities available for sale $ 3,357 $ 235 $ 111 Gross realized losses from sales of debt securities available for sale (1,225 ) (129 ) (122 ) Other securities losses, net (1) — (195 ) — Investment securities gains (losses), net $ 2,132 $ (89 ) $ (11 ) __________ (1) Other securities losses, net includes net unrealized loss activity associated with equity securities.
Schedule of Contractual Maturities of Investment Securities Available for Sale	The scheduled contractual maturities of debt securities available for sale at December 31, 2019 are presented as follows: December 31, 2019 Amortized Cost Fair Value (in thousands) Due within one year $ 77,363 $ 77,538 Due after one year through five years 416,556 421,363 Due after five years through ten years 2,007,225 2,041,751 Due after ten years 1,201,952 1,205,490 Total debt securities available for sale $ 3,703,096 $ 3,746,142
Schedule of Securities pledged as collateral [Table Text Block]	The following table summarizes the carrying value of securities pledged as collateral to secure public deposits, borrowings and other purposes as permitted or required by law: December 31, 2019 2018 (in thousands) To secure public funds $ 323,055 $ 276,343 To secure borrowings 111,488 52,303 Other securities pledged 154,030 138,492 Total securities pledged as collateral $ 588,573 $ 467,138
Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses	The following tables show the gross unrealized losses and fair value of the Company’s debt securities available for sale with unrealized losses that are not deemed to be other-than-temporarily impaired, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position at December 31, 2019 and 2018 : Less than 12 Months 12 Months or More Total Fair Unrealized Fair Unrealized Fair Unrealized December 31, 2019 (in thousands) U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 1,055,903 $ (12,424 ) $ 491,539 $ (6,798 ) $ 1,547,442 (19,222 ) Other asset-backed securities (1) 89,508 (880 ) 6,799 (109 ) 96,307 (989 ) State and municipal securities 12,363 (142 ) 12,587 (82 ) 24,950 (224 ) U.S. government agency and government-sponsored enterprise securities — — 10,495 (5 ) 10,495 (5 ) Total $ 1,157,774 $ (13,446 ) $ 521,420 $ (6,994 ) $ 1,679,194 $ (20,440 ) December 31, 2018 U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 114,551 $ (750 ) $ 1,207,020 $ (40,096 ) $ 1,321,571 $ (40,846 ) Other asset-backed securities (1) 40,071 (222 ) 94,367 (2,399 ) 134,438 (2,621 ) State and municipal securities 106,292 (581 ) 280,496 (7,179 ) 386,788 (7,760 ) U.S. government agency and government-sponsored enterprise securities 15,392 (45 ) 291,435 (4,691 ) 306,827 (4,736 ) U.S. government securities — — 247 (3 ) 247 (3 ) Total $ 276,306 $ (1,598 ) $ 1,873,565 $ (54,368 ) $ 2,149,871 $ (55,966 ) __________ (1) Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation.

Loans (Tables)

Loans (Tables)	12 Months Ended
	Dec. 31, 2019
Financing Receivable, Credit Quality Indicator [Line Items]
Analysis of Loan Portfolio by Major Types of Loans	The following is an analysis of the loan portfolio by segment (net of unearned income): December 31, 2019 2018 Loans, excluding PCI loans PCI Loans Total Loans, excluding PCI loans PCI Loans Total (in thousands) Commercial business $ 3,602,597 $ 7,863 $ 3,610,460 $ 3,438,422 $ 9,240 $ 3,447,662 Real estate: One-to-four family residential 265,144 7,203 272,347 238,367 8,017 246,384 Commercial and multifamily residential 4,183,961 54,212 4,238,173 3,846,027 62,910 3,908,937 Total real estate 4,449,105 61,415 4,510,520 4,084,394 70,927 4,155,321 Real estate construction: One-to-four family residential 192,762 — 192,762 217,790 153 217,943 Commercial and multifamily residential 163,103 — 163,103 284,394 534 284,928 Total real estate construction 355,865 — 355,865 502,184 687 502,871 Consumer 292,697 8,238 300,935 318,945 8,906 327,851 Less: Net unearned income (34,315 ) — (34,315 ) (42,194 ) — (42,194 ) Total loans, net of unearned income 8,665,949 77,516 8,743,465 8,301,751 89,760 8,391,511 Less: ALLL (81,124 ) (2,844 ) (83,968 ) (79,758 ) (3,611 ) (83,369 ) Total loans, net $ 8,584,825 $ 74,672 $ 8,659,497 $ 8,221,993 $ 86,149 $ 8,308,142 Loans held for sale $ 17,718 $ — $ 17,718 $ 3,849 $ — $ 3,849
Analysis of Nonaccrual Loans	The following is an analysis of nonaccrual loans as of December 31, 2019 and 2018 : December 31, 2019 2018 Recorded Unpaid Principal Recorded Unpaid Principal (in thousands) Commercial business: Secured $ 26,615 $ 38,278 $ 35,504 $ 45,072 Unsecured 359 360 9 9 Real estate: One-to-four family residential 591 632 1,158 1,178 Commercial and multifamily residential: Commercial land 1,985 1,994 2,261 2,270 Income property 205 206 2,721 3,062 Owner occupied 1,287 1,325 9,922 10,300 Real estate construction: One-to-four family residential: Land and acquisition — — 318 318 Residential construction — 59 — — Consumer 2,018 2,355 2,949 3,149 Total $ 33,060 $ 45,209 $ 54,842 $ 65,358
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Analysis of the Aged Loan Portfolio	The following is an aging of the recorded investment of the loan portfolio as of December 31, 2019 and 2018 : Current 30 - 59 60 - 89 Greater Total Nonaccrual Total Loans December 31, 2019 (in thousands) Commercial business: Secured $ 3,422,313 $ 7,684 $ 5,035 $ — $ 12,719 $ 26,615 $ 3,461,647 Unsecured 128,852 392 80 — 472 359 129,683 Real estate: One-to-four family residential 261,886 2,162 256 — 2,418 591 264,895 Commercial and multifamily residential: Commercial land 300,580 625 — — 625 1,985 303,190 Income property 2,057,359 1,797 — — 1,797 205 2,059,361 Owner occupied 1,795,771 4,287 — — 4,287 1,287 1,801,345 Real estate construction: One-to-four family residential: Land and acquisition 1,364 — — — — — 1,364 Residential construction 189,350 951 — — 951 — 190,301 Commercial and multifamily residential: Income property 88,389 — — — — — 88,389 Owner occupied 73,203 — — — — — 73,203 Consumer 290,174 284 95 — 379 2,018 292,571 Total $ 8,609,241 $ 18,182 $ 5,466 $ — $ 23,648 $ 33,060 $ 8,665,949 Current 30 - 59 60 - 89 Greater Total Nonaccrual Total Loans December 31, 2018 (in thousands) Commercial business: Secured $ 3,267,709 $ 5,864 $ 3,624 $ — $ 9,488 $ 35,504 $ 3,312,701 Unsecured 111,868 240 — — 240 9 112,117 Real estate: One-to-four family residential 233,941 694 233 — 927 1,158 236,026 Commercial and multifamily residential: Commercial land 283,416 — — — — 2,261 285,677 Income property 1,910,505 5,009 2,241 — 7,250 2,721 1,920,476 Owner occupied 1,606,085 1,744 — — 1,744 9,922 1,617,751 Real estate construction: One-to-four family residential: Land and acquisition 4,099 — — — — 318 4,417 Residential construction 212,303 93 — — 93 — 212,396 Commercial and multifamily residential: Income property 194,912 — — — — — 194,912 Owner occupied 79,805 7,258 — — 7,258 — 87,063 Consumer 314,008 1,057 201 — 1,258 2,949 318,215 Total $ 8,218,651 $ 21,959 $ 6,299 $ — $ 28,258 $ 54,842 $ 8,301,751
Impaired Financing Receivables	The following is an analysis of the impaired loans (see Note 1, “Summary of Significant Accounting Policies,” ) as of December 31, 2019 and 2018 : Recorded Investment Recorded Investment Impaired Loans With Impaired Loans Without Recorded Unpaid Related Recorded Unpaid December 31, 2019 (in thousands) Commercial business: Secured $ 3,437,564 $ 24,083 $ 3,286 $ 3,851 $ 93 $ 20,797 $ 28,658 Unsecured 129,671 12 12 12 — — — Real estate: One-to-four family residential 264,513 382 299 588 5 83 182 Commercial and multifamily residential: Commercial land 300,973 2,217 1,592 1,601 312 625 663 Income property 2,059,361 — — — — — — Owner occupied 1,797,682 3,663 3,663 5,233 29 — — Real estate construction: One-to-four family residential: Land and acquisition 1,364 — — — — — — Residential construction 190,301 — — — — — — Commercial and multifamily residential: Income property 88,389 — — — — — — Owner occupied 73,203 — — — — — — Consumer 290,934 1,637 483 637 22 1,154 1,310 Total $ 8,633,955 $ 31,994 $ 9,335 $ 11,922 $ 461 $ 22,659 $ 30,813 Recorded Investment Recorded Investment Impaired Loans With Impaired Loans Without Recorded Unpaid Related Recorded Unpaid December 31, 2018 (in thousands) Commercial business: Secured $ 3,286,416 $ 26,285 $ 6,350 $ 8,460 $ 2,023 $ 19,935 $ 24,404 Unsecured 112,097 20 20 20 — — — Real estate: One-to-four family residential 235,138 888 325 798 8 563 575 Commercial and multifamily residential: Commercial land 283,451 2,226 — — — 2,226 2,272 Income property 1,917,522 2,954 99 165 1 2,855 3,011 Owner occupied 1,605,042 12,709 3,231 4,666 69 9,478 9,750 Real estate construction: One-to-four family residential Land and acquisition 4,417 — — — — — — Residential construction 212,396 — — — — — — Commercial and multifamily residential: Income property 194,912 — — — — — — Owner occupied 87,063 — — — — — — Consumer 314,193 4,022 3,326 3,584 31 696 704 Total $ 8,252,647 $ 49,104 $ 13,351 $ 17,693 $ 2,132 $ 35,753 $ 40,716 The following table provides additional information on impaired loans for the years ended December 31, 2019 , 2018 and 2017 : Years Ended December 31, 2019 2018 2017 Average Recorded Interest Recognized Average Recorded Interest Recognized Average Recorded Interest Recognized (in thousands) Commercial business Secured $ 24,682 $ 202 $ 39,701 $ 81 $ 20,282 $ 60 Unsecured 16 1 191 2 5 — Real estate: One-to-four family residential 665 42 748 42 730 49 Commercial and multifamily residential Commercial land 2,606 31 2,371 34 2,079 — Income property 1,121 — 3,284 130 4,314 51 Owner occupied 10,681 168 9,730 720 5,335 445 Real estate construction: One-to-four family residential Land and acquisition — — — — 3 — Residential construction — — 484 — 309 — Owner occupied — — 3,240 — 1,620 203 Consumer 2,960 8 5,712 129 5,973 163 Total $ 42,731 $ 452 $ 65,461 $ 1,138 $ 40,650 $ 971
Analysis of loans classified as Troubled Debt Restructurings (“TDR”)	The following is an analysis of loans classified as TDR for the years ended December 31, 2019 , 2018 and 2017 : Years Ended December 31, 2019 2018 2017 Number of TDR Modifications Pre-Modification Post-Modification Number of TDR Modifications Pre-Modification Post-Modification Number of TDR Modifications Pre-Modification Post-Modification (dollars in thousands) Commercial business: Secured 11 $ 6,642 $ 6,642 12 $ 18,379 $ 18,379 10 $ 5,655 $ 5,655 Unsecured — — — — — — 1 26 26 Real estate: One-to-four family residential 1 45 45 — — — 3 583 583 Commercial and multifamily residential: Commercial land — — — — — — 1 687 687 Income property 1 217 217 1 891 891 1 1,152 1,152 Owner occupied — — — — — — 1 78 78 Real estate construction: Commercial and multifamily residential: Owner occupied — — — — — — 1 4,050 4,050 Consumer 11 444 444 21 2,777 2,777 42 5,891 5,891 Total 24 $ 7,348 $ 7,348 34 $ 22,047 $ 22,047 60 $ 18,122 $ 18,122
Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Analysis of Loan Portfolio by Major Types of Loans	The following is an analysis of our PCI loans, net of related allowance for losses and remaining valuation discounts as of December 31, 2019 and 2018 : December 31, 2019 2018 (in thousands) Commercial business $ 8,083 $ 9,672 Real estate: One-to-four family residential 8,453 9,848 Commercial and multifamily residential 56,752 66,340 Total real estate 65,205 76,188 Real estate construction: One-to-four family residential — 153 Commercial and multifamily residential — 507 Total real estate construction — 660 Consumer 8,984 9,765 Subtotal of PCI loans 82,272 96,285 Less: Valuation discount resulting from acquisition accounting 4,756 6,525 ALLL 2,844 3,611 PCI loans, net of valuation discounts and allowance for loan losses $ 74,672 $ 86,149
Changes in Accretable Yield for Acquired Loans [Table Text Block]	The following table shows the changes in accretable yield for acquired loans for the years ended December 31, 2019 , 2018 , and 2017 : Years Ended December 31, 2019 2018 2017 (in thousands) Balance at beginning of period $ 21,949 $ 31,176 $ 45,191 Accretion (6,053 ) (8,194 ) (12,357 ) Disposals 46 (387 ) (158 ) Reclassifications from (to) nonaccretable difference 3,719 (646 ) (1,500 ) Balance at end of period $ 19,661 $ 21,949 $ 31,176

Allowance for Loan and Lease _2

Allowance for Loan and Lease Losses and Unfunded Commitments and Letters of Credit (Tables)	12 Months Ended
	Dec. 31, 2019
Financing Receivable, Allowance for Credit Loss [Line Items]
Changes in the Allowance for Loan and Lease Losses	The following tables show a detailed analysis of the ALLL for the years ended December 31, 2019 , 2018 and 2017 : Beginning Charge-offs Recoveries Provision (Recapture) Ending Specific General Year Ended December 31, 2019 (in thousands) Commercial business: Secured $ 43,188 $ (10,249 ) $ 2,755 $ 7,381 $ 43,075 $ 93 $ 42,982 Unsecured 2,626 (75 ) 350 184 3,085 — 3,085 Real estate: One-to-four family residential 593 (2 ) 242 (226 ) 607 5 602 Commercial and multifamily residential: Commercial land 3,947 — 286 2,146 6,379 312 6,067 Income property 4,044 — 320 2,062 6,426 — 6,426 Owner occupied 4,533 — 4 1,567 6,104 29 6,075 Real estate construction: One-to-four family residential: Land and acquisition 549 — 362 (799 ) 112 — 112 Residential construction 5,536 (170 ) 3,092 (3,982 ) 4,476 — 4,476 Commercial and multifamily residential: Income property 5,784 — 1 (3,286 ) 2,499 — 2,499 Owner occupied 2,604 — — 702 3,306 — 3,306 Consumer 5,301 (1,400 ) 930 (376 ) 4,455 22 4,433 PCI 3,611 (3,319 ) 3,979 (1,427 ) 2,844 — 2,844 Unallocated 1,053 — — (453 ) 600 — 600 Total $ 83,369 $ (15,215 ) $ 12,321 $ 3,493 $ 83,968 $ 461 $ 83,507 Beginning Charge-offs Recoveries Provision (Recapture) Ending Specific General Year Ended December 31, 2018 (in thousands) Commercial business: Secured $ 29,341 $ (11,560 ) $ 3,024 $ 22,383 $ 43,188 $ 2,023 $ 41,165 Unsecured 2,000 (159 ) 403 382 2,626 — 2,626 Real estate: One-to-four family residential 701 — 408 (516 ) 593 8 585 Commercial and multifamily residential: Commercial land 4,265 — 99 (417 ) 3,947 — 3,947 Income property 5,672 (780 ) 912 (1,760 ) 4,044 1 4,043 Owner occupied 5,459 — 20 (946 ) 4,533 69 4,464 Real estate construction: One-to-four family residential: Land and acquisition 963 — 726 (1,140 ) 549 — 549 Residential construction 3,709 — 890 937 5,536 — 5,536 Commercial and multifamily residential: Income property 7,053 — — (1,269 ) 5,784 — 5,784 Owner occupied 4,413 — — (1,809 ) 2,604 — 2,604 Consumer 5,163 (1,194 ) 1,180 152 5,301 31 5,270 PCI 6,907 (4,862 ) 3,847 (2,281 ) 3,611 — 3,611 Unallocated — — — 1,053 1,053 — 1,053 Total $ 75,646 $ (18,555 ) $ 11,509 $ 14,769 $ 83,369 $ 2,132 $ 81,237 Beginning Charge-offs Recoveries Provision (Recapture) Ending Specific General Year Ended December 31, 2017 (in thousands) Commercial business: Secured $ 36,050 $ (7,524 ) $ 4,283 $ (3,468 ) $ 29,341 $ 1,867 $ 27,474 Unsecured 960 (89 ) 553 576 2,000 3 1,997 Real estate: One-to-four family residential 599 (460 ) 568 (6 ) 701 103 598 Commercial and multifamily residential: Commercial land 1,797 — 53 2,415 4,265 — 4,265 Income property 7,342 (287 ) 498 (1,881 ) 5,672 185 5,487 Owner occupied 6,439 — 124 (1,104 ) 5,459 3 5,456 Real estate construction: One-to-four family residential: Land and acquisition 316 (14 ) 72 589 963 — 963 Residential construction 669 — 106 2,934 3,709 — 3,709 Commercial and multifamily residential: Income property 404 — 1 6,648 7,053 — 7,053 Owner occupied 1,192 — — 3,221 4,413 — 4,413 Consumer 3,534 (1,474 ) 1,187 1,916 5,163 199 4,964 PCI 10,515 (6,812 ) 6,187 (2,983 ) 6,907 — 6,907 Unallocated 226 — — (226 ) — — — Total $ 70,043 $ (16,660 ) $ 13,632 $ 8,631 $ 75,646 $ 2,360 $ 73,286
Changes in the Allowance for Unfunded Commitments and Letters of Credit	Changes in the allowance for unfunded commitments and letters of credit, a component of “Other liabilities” in the Consolidated Balance Sheets, are summarized as follows: Years Ended December 31, 2019 2018 2017 (in thousands) Beginning balance $ 4,330 $ 3,130 $ 2,705 Net changes in the allowance for unfunded commitments and letters of credit (900 ) 1,200 425 Ending balance $ 3,430 $ 4,330 $ 3,130
Financing Receivable Credit Quality Indicators [Table Text Block]	The following is an analysis of the credit quality of our loan portfolio, excluding PCI loans as of December 31, 2019 and 2018 : Pass Special Mention Substandard Doubtful Loss Total December 31, 2019 (in thousands) Loans, excluding PCI loans Commercial business: Secured $ 3,296,776 $ 37,394 $ 127,477 $ — $ — $ 3,461,647 Unsecured 129,518 — 165 — — 129,683 Real estate: One-to-four family residential 264,051 — 844 — — 264,895 Commercial and multifamily residential: Commercial land 283,254 1,344 18,592 — — 303,190 Income property 2,014,233 5,658 39,470 — — 2,059,361 Owner occupied 1,757,757 6,158 37,430 — — 1,801,345 Real estate construction: One-to-four family residential: Land and acquisition 1,364 — — — — 1,364 Residential construction 190,301 — — — — 190,301 Commercial and multifamily residential: Income property 88,389 — — — — 88,389 Owner occupied 73,203 — — — — 73,203 Consumer 289,588 — 2,983 — — 292,571 Total $ 8,388,434 $ 50,554 $ 226,961 $ — $ — 8,665,949 Less: ALLL 81,124 Loans, excluding PCI loans, net $ 8,584,825 Pass Special Mention Substandard Doubtful Loss Total December 31, 2018 (in thousands) Loans, excluding PCI loans Commercial business: Secured $ 3,160,910 $ 48,779 $ 103,007 $ 5 $ — $ 3,312,701 Unsecured 112,091 21 — 5 — 112,117 Real estate: One-to-four family residential 234,416 — 1,610 — — 236,026 Commercial and multifamily residential: Commercial land 276,348 5,082 4,247 — — 285,677 Income property 1,876,925 36,998 6,553 — — 1,920,476 Owner occupied 1,556,852 14,964 45,935 — — 1,617,751 Real estate construction: One-to-four family residential: Land and acquisition 4,099 — 318 — — 4,417 Residential construction 212,225 — 171 — — 212,396 Commercial and multifamily residential: Income property 194,912 — — — — 194,912 Owner occupied 87,063 — — — — 87,063 Consumer 313,817 — 4,398 — — 318,215 Total $ 8,029,658 $ 105,844 $ 166,239 $ 10 $ — 8,301,751 Less: ALLL 79,758 Loans, excluding PCI loans, net $ 8,221,993 The following is an analysis of the credit quality of our PCI loan portfolio as of December 31, 2019 and 2018 : Pass Special Mention Substandard Doubtful Loss Total December 31, 2019 (in thousands) PCI loans: Commercial business: Secured $ 6,109 $ 962 $ 606 $ — $ — $ 7,677 Unsecured 406 — — — — 406 Real estate: One-to-four family residential 8,351 — 102 — — 8,453 Commercial and multifamily residential: Commercial land 8,720 497 212 — — 9,429 Income property 18,386 — 297 — — 18,683 Owner occupied 21,077 — 7,563 — — 28,640 Consumer 8,758 — 226 — — 8,984 Total $ 71,807 $ 1,459 $ 9,006 $ — $ — 82,272 Less: Valuation discount resulting from acquisition accounting 4,756 ALLL 2,844 PCI loans, net $ 74,672 Pass Special Mention Substandard Doubtful Loss Total December 31, 2018 (in thousands) PCI loans: Commercial business: Secured $ 8,041 $ — $ 840 $ — $ — $ 8,881 Unsecured 692 — 99 — — 791 Real estate: One-to-four family residential 9,633 — 215 — — 9,848 Commercial and multifamily residential: Commercial land 10,363 — — — — 10,363 Income property 19,680 — — — — 19,680 Owner occupied 35,944 — 353 — — 36,297 Real estate construction: One-to-four family residential: Land and acquisition 151 — 2 — — 153 Commercial and multifamily residential: Income property 507 — — — — 507 Consumer 9,326 — 439 — — 9,765 Total $ 94,337 $ — $ 1,948 $ — $ — 96,285 Less: Valuation discount resulting from acquisition accounting 6,525 ALLL 3,611 PCI loans, net $ 86,149

Other Real Estate Owned (Tables

Other Real Estate Owned (Tables)	12 Months Ended
	Dec. 31, 2019
Other Real Estate, Foreclosed Assets, and Repossessed Assets [Abstract]
Summary of Other Real Estate Owned	The following table sets forth activity in OREO for the periods indicated: Years Ended December 31, 2019 2018 (in thousands) Balance, beginning of period $ 6,019 $ 13,298 Transfers in 386 1,200 Valuation adjustments (195 ) (698 ) Proceeds from sale of OREO property (6,455 ) (7,261 ) Gain (loss) on sale of OREO, net 797 (520 ) Balance, end of period $ 552 $ 6,019

Premises and Equipment (Tables)

Premises and Equipment (Tables)	12 Months Ended
	Dec. 31, 2019
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment	Real and personal property and software, less accumulated depreciation and amortization, were as follows: December 31, 2019 2018 (in thousands) Land $ 53,124 $ 54,185 Buildings 107,371 108,890 Leasehold improvements 28,459 27,859 Furniture and equipment 37,929 32,292 Vehicles 510 511 Computer software 15,936 19,358 Total cost 243,329 243,095 Less accumulated depreciation and amortization (77,921 ) (74,307 ) Total $ 165,408 $ 168,788

Goodwill and Intangible Assets

Goodwill and Intangible Assets (Tables)	12 Months Ended
	Dec. 31, 2019
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill and Intangible Assets	The following table sets forth activity for goodwill and other intangible assets for the periods indicated: Years Ended December 31, 2019 2018 2017 (in thousands) Goodwill, beginning of period $ 765,842 $ 765,842 $ 382,762 Established through acquisitions (1) — — 383,080 Total goodwill, end of period 765,842 765,842 765,842 Other intangible assets, net CDI: Gross CDI balance, beginning of period 105,473 105,473 58,598 Accumulated amortization, beginning of period (60,455 ) (48,219 ) (41,886 ) CDI, net, beginning of period 45,018 57,254 16,712 Established through acquisitions (1) — — 46,875 CDI current period amortization (10,479 ) (12,236 ) (6,333 ) Total CDI, end of period 34,539 45,018 57,254 Intangible assets not subject to amortization 919 919 919 Other intangible assets, net at end of period 35,458 45,937 58,173 Total goodwill and intangible assets, end of period $ 801,300 $ 811,779 $ 824,015 __________ (1) See Note 2, “Business Combinations,” for additional information regarding the goodwill and CDI related to the acquisition of Pacific Continental on November 1, 2017.
Estimated Future Amortization Expense of Core Deposit Intangibles	The following table provides the estimated future amortization expense of CDI for the succeeding five years: Years Ending December 31, (in thousands) 2020 $ 8,724 2021 7,264 2022 5,880 2023 4,552 2024 3,432

Leases (Tables)

Leases (Tables)	12 Months Ended
	Dec. 31, 2019
Leases [Abstract]
Operating Leases by balance sheet location [Table Text Block]	The following table shows the details of the Company’s operating lease right-of-use asset and the associated lease liability for the period indicated: Item Balance Sheet Location December 31, 2019 (in thousands) Operating lease asset Other assets $ 57,226 Operating lease liability Other liabilities $ 63,030
Lease, Cost [Table Text Block]	The following table shows the components of net lease costs: Item Statement of Income Location Year Ended December 31, 2019 (in thousands) Operating lease cost (1) Occupancy $ 10,851 Variable lease cost Occupancy 1,805 Sublease income Occupancy (1,182 ) Net lease cost $ 11,474 __________ (1) Includes short-term lease costs, which are immaterial.
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	The following table shows the maturity analysis for operating leases as of December 31, 2019 : Year ending December 31, (in thousands) 2020 $ 11,105 2021 11,126 2022 10,689 2023 9,476 2024 6,980 Thereafter 21,866 Total future minimum lease payments 71,242 Amounts representing interest (8,212 ) Present value of minimum lease payments $ 63,030
Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block]	Future minimum lease payments for the Company’s operating leases as of December 31, 2018, prior to the adoption of the new lease guidance were as follows: Year Ending December 31, (in thousands) 2019 $ 10,947 2020 9,766 2021 8,729 2022 8,102 2023 6,796 Thereafter 18,703 Total minimum payments $ 63,043

Deposits (Tables)

Deposits (Tables)	12 Months Ended
	Dec. 31, 2019
Deposits [Abstract]
Schedule Of Deposits	Year end deposits are summarized in the following table: December 31, 2019 2018 (in thousands) Demand and other noninterest-bearing $ 5,328,146 $ 5,227,216 Money market (1) 2,322,644 2,294,125 Interest-bearing demand (1) 1,150,437 1,084,863 Savings (1) 882,050 889,849 Interest-bearing public funds, other than certificates of deposit (1) 301,203 233,938 Certificates of deposit, less than $250,000 218,764 243,849 Certificates of deposit, $250,000 or more 151,995 89,473 Certificates of deposit insured by CDARS ® 17,065 23,580 Brokered certificates of deposit 12,259 57,930 Reciprocal money market accounts 300,158 313,692 Subtotal 10,684,721 10,458,515 Valuation adjustment resulting from acquisition accounting (13 ) (389 ) Total deposits $ 10,684,708 $ 10,458,126
Schedule Of Time Deposits Maturity	The following table shows the amount and maturity of time deposits: Years Ending December 31, (in thousands) 2020 $ 313,241 2021 53,679 2022 19,346 2023 8,060 2024 5,593 Thereafter 151 Total $ 400,070

Federal Home Loan Bank and Fe_2

Federal Home Loan Bank and Federal Reserve Bank Borrowings (Tables) - Federal Home Loan Bank Advances [Member]	12 Months Ended
	Dec. 31, 2019
Debt Instrument [Line Items]
Schedule of Maturities of Long-term Debt	At December 31, 2019 , FHLB advances were scheduled to mature as follows: Federal Home Loan Bank Advances Weighted Average Rate Amount (dollars in thousands) Within 1 year 1.82 % $ 946,000 Over 1 through 5 years 3.85 % 2,000 Due after 10 years 5.37 % 5,000 Total 953,000 Valuation adjustment from acquisition accounting 469 Total $ 953,469
Debt Instrument Activity For Year	The maximum, average outstanding and year end balances and average interest rates on advances from the FHLB were as follows for the years ended December 31, 2019 , 2018 and 2017 : Years ended December 31, 2019 2018 2017 (dollars in thousands) Balance at end of period $ 953,469 $ 399,523 $ 11,579 Average balance during period $ 469,983 $ 166,563 $ 79,788 Maximum month end balance during period $ 953,469 $ 399,523 $ 317,480 Weighted average rate during period 2.42 % 2.29 % 1.33 % Weighted average rate at December 31 1.84 % 2.68 % 4.08 %

Derivatives and Balance Sheet_2

Derivatives and Balance Sheet Offsetting (Tables)	12 Months Ended
	Dec. 31, 2019
Derivative [Line Items]
Balance Sheet Offsetting [Table Text Block]	The following tables show the gross interest rate swap contracts, collar agreements and repurchase agreements in the Consolidated Balance Sheets and the respective collateral received or pledged in the form of cash or other financial instruments. The collateral amounts in these tables are limited to the outstanding balances of the related asset or liability. Therefore, instances of overcollateralization are not shown. Gross Amounts of Recognized Assets/Liabilities Gross Amounts Offset in the Consolidated Balance Sheets Net Amounts of Assets/Liabilities Presented in the Consolidated Balance Sheets Gross Amounts Not Offset in the Consolidated Balance Sheets Collateral Pledged/Received Net Amount December 31, 2019 (in thousands) Assets Interest rate swap contracts $ 19,144 $ — $ 19,144 $ — $ 19,144 Interest rate collar $ 14,727 $ — $ 14,727 $ (14,727 ) $ — Liabilities Interest rate swap contracts $ 19,145 $ — $ 19,145 $ (19,145 ) $ — Repurchase agreements $ 64,437 $ — $ 64,437 $ (64,437 ) $ — December 31, 2018 Assets Interest rate swap contracts $ 7,033 $ — $ 7,033 $ — $ 7,033 Liabilities Interest rate swap contracts $ 7,033 $ — $ 7,033 $ (3,235 ) $ 3,798 Repurchase agreements $ 61,094 $ — $ 61,094 $ (61,094 ) $ —
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Schedule of Fair Value Derivative Instruments	The following table presents the fair value of derivatives, as well as their classification on the Balance Sheet at December 31, 2019 and 2018 : Asset Derivatives Liability Derivatives 2019 2018 2019 2018 Balance Sheet Fair Value Balance Sheet Fair Value Balance Sheet Fair Value Balance Sheet Fair Value (in thousands) Derivatives designated as hedging instruments: Interest rate collar Other assets $ 14,727 Other assets $ — Other liabilities $ — Other liabilities $ — Derivatives not designated as hedging instruments: Interest rate swap contracts Other assets $ 19,144 Other assets $ 7,033 Other liabilities $ 19,145 Other liabilities $ 7,033
Available-for-sale Securities [Member]
Derivative [Line Items]
Schedule of Financial Instruments Owned and Pledged as Collateral [Table Text Block]	The following table presents the class of collateral pledged for repurchase agreements as well as the remaining contractual maturity of the repurchase agreements: Remaining contractual maturity of the agreements Overnight and continuous Up to 30 days 30 - 90 days Greater than 90 days Total December 31, 2019 (in thousands) Class of collateral pledged for repurchase agreements U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations $ 64,437 $ — $ — $ — $ 64,437 Gross amount of recognized liabilities for repurchase agreements 64,437 Amounts related to agreements not included in offsetting disclosure $ —

Employee Benefit Plans (Tables)

Employee Benefit Plans (Tables)	12 Months Ended
	Dec. 31, 2019
Employee Benefit [Line Items]
Schedule of Accumulated and Projected Benefit Obligations	The following table reconciles the accumulated liability for the projected benefit obligation: December 31, 2019 2018 (in thousands) Balance, beginning of year $ 21,287 $ 20,553 Actuarial (gain) loss 2,663 (31 ) Benefit expense 1,930 1,701 Benefit payments (966 ) (936 ) Balance, end of year $ 24,914 $ 21,287
SERP [Member]
Employee Benefit [Line Items]
Schedule of Expected Benefit Payments	The benefits expected to be paid in conjunction with the SERP are presented in the following table: Years Ending December 31, (in thousands) 2020 $ 1,971 2021 1,116 2022 1,135 2023 1,239 2024 1,438 2025 through 2029 8,574 Total $ 15,473

Shareholders' Equity Dividends

Shareholders' Equity Dividends declared (Tables)	12 Months Ended
	Dec. 31, 2019
Equity [Abstract]
Dividends, Common Stock, Cash	The following summarizes the dividend activity for the year ended December 31, 2019 : Declared Regular Cash Dividends Per Common Share Special Cash Dividends Per Common Share Record Date Paid Date January 24, 2019 $ 0.28 $ 0.14 February 6, 2019 February 20, 2019 April 25, 2019 $ 0.28 $ 0.14 May 8, 2019 May 22, 2019 July 25, 2019 $ 0.28 $ — August 7, 2019 August 21, 2019 October 24, 2019 $ 0.28 $ — November 6, 2019 November 20, 2019

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Income (Tables)	12 Months Ended
	Dec. 31, 2019
Accumulated Other Comprehensive Income [Abstract]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table shows changes in accumulated other comprehensive income (loss) by component for the years ended December 31, 2019 , 2018 and 2017 : Unrealized Gains and Losses on Available for Sale Securities (1) Unrealized Gains and Losses on Pension Plan Liability (1) Unrealized Gains and Losses on Hedging Instruments (1) Total (1) Year Ended December 31, 2019 (in thousands) Beginning balance $ (33,128 ) $ (2,177 ) $ — $ (35,305 ) Other comprehensive income (loss) before reclassifications 67,802 (2,042 ) 11,760 77,520 Amounts reclassified from accumulated other comprehensive loss (2) (1,636 ) 245 (457 ) (1,848 ) Net current-period other comprehensive income (loss) 66,166 (1,797 ) 11,303 75,672 Ending balance $ 33,038 $ (3,974 ) $ 11,303 $ 40,367 Year Ended December 31, 2018 Beginning balance $ (19,779 ) $ (2,446 ) $ — $ (22,225 ) Adjustment pursuant to adoption of ASU 2016-01 157 — — 157 Other comprehensive income (loss) before reclassifications (13,425 ) 24 — (13,401 ) Amounts reclassified from accumulated other comprehensive loss (2) (81 ) 245 — 164 Net current-period other comprehensive income (loss) (13,506 ) 269 — (13,237 ) Ending balance $ (33,128 ) $ (2,177 ) $ — $ (35,305 ) Year Ended December 31, 2017 Beginning balance $ (12,704 ) $ (6,295 ) $ — $ (18,999 ) Other comprehensive income (loss) before reclassifications (3,391 ) 4,017 — 626 Amounts reclassified from accumulated other comprehensive loss (2) 7 223 — 230 Net current-period other comprehensive income (loss) (3,384 ) 4,240 — 856 Adjustment pursuant to adoption of ASU 2018-02 $ (3,691 ) $ (391 ) $ — $ (4,082 ) Ending balance $ (19,779 ) $ (2,446 ) $ — $ (22,225 ) __________ (1) All amounts are net of tax. Amounts in parenthesis indicate debits. (2) See following table for details about these reclassifications.
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	ed in OCI. The following table shows details regarding the reclassifications from accumulated other comprehensive income for the years ended December 31, 2019 , 2018 and 2017 : Amount Reclassified from Accumulated Other Comprehensive Income Affected line Item in the Consolidated Statement of Income Years Ended December 31, 2019 2018 2017 (in thousands) Unrealized gains and losses on available for sale debt securities $ 2,132 $ 106 $ (11 ) Investment securities gains (losses), net 2,132 106 (11 ) Total before tax (496 ) (25 ) 4 Income tax provision $ 1,636 $ 81 $ (7 ) Net of tax Amortization of pension plan liability actuarial losses $ (319 ) $ (319 ) $ (350 ) Compensation and employee benefits (319 ) (319 ) (350 ) Total before tax 74 74 127 Income tax provision $ (245 ) $ (245 ) $ (223 ) Net of tax Unrealized gains from hedging instruments $ 595 $ — $ — Loans 595 — — Total before tax (138 ) — — Income tax provision $ 457 $ — $ — Net of tax

Fair Value Accounting and Mea_2

Fair Value Accounting and Measurement (Tables)	12 Months Ended
	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value Inputs, Assets, Quantitative Information	The range and weighted average of the significant unobservable inputs used to fair value our Level 3 nonrecurring assets during 2019 and 2018 , along with the valuation techniques used, are shown in the following tables: Fair Value at Valuation Technique Unobservable Input Range (Weighted Average) (1) (dollars in thousands) Impaired loans - collateral-dependent (2) $ 10,007 Fair Market Value of Collateral Adjustment to Stated Value 0% - 100% (49.68%) __________ (1) Adjustment applied to appraisal value and stated value (in the case of fixed assets and inventory). (2) Collateral consists of accounts receivable, inventory, fixed assets, real estate and cash. Fair Value at Valuation Technique Unobservable Input Range (Weighted Average) (1) (dollars in thousands) Impaired loans - collateral-dependent (2) $ 8,394 Fair Market Value of Collateral Adjustment to Stated Value 0.00% - 70.04% (7.02%) Impaired loans - other (3) $ 3,161 Discounted Cash Flow Discount Rate 0.34 % __________ (1) Discount rate applied to discounted cash flow valuation or appraisal value and stated value (in the case of fixed assets and inventory). (2) Collateral consists of accounts receivable, inventory, fixed assets, real estate and cash. (3) As there was only one impaired loan re-measured using discounted cash flows, a range of discounts could not be provided. The following table sets forth the Company’s financial assets and liabilities that were accounted for at fair value on a recurring basis at December 31, 2019 and 2018 by level within the fair value hierarchy. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement: Fair Value at Fair Value Measurements at Reporting Date Using Level 1 Level 2 Level 3 (in thousands) Assets Debt securities available for sale U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,892,950 $ — $ 2,892,950 $ — Other asset-backed securities (1) 196,050 — 196,050 — State and municipal securities 488,802 — 488,802 — U.S. government agency and government-sponsored enterprise securities 168,340 — 168,340 — Total debt securities available for sale $ 3,746,142 $ — $ 3,746,142 $ — Other assets: Interest rate contracts $ 19,144 $ — $ 19,144 $ — Interest rate collar 14,727 — 14,727 — Liabilities Other liabilities: Interest rate contracts $ 19,145 $ — $ 19,145 $ — Fair Value at Fair Value Measurements at Reporting Date Using Level 1 Level 2 Level 3 (in thousands) Assets Debt securities available for sale U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations (1) $ 2,013,355 $ — $ 2,013,355 $ — Other asset-backed securities (1) 174,935 — 174,935 — State and municipal securities 574,323 — 574,323 — U.S. government agency and government-sponsored enterprise securities 404,587 — 404,587 — U.S. government securities 248 248 — — Total debt securities available for sale $ 3,167,448 $ 248 $ 3,167,200 $ — Other assets: Interest rate contracts $ 7,033 $ — $ 7,033 $ — Liabilities Other liabilities: Interest rate contracts $ 7,033 $ — $ 7,033 $ — __________ (1) Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation.
Financial Assets Accounted For Fair Value On Nonrecurring Basis	The following table sets forth the Company’s assets that were measured using fair value estimates on a nonrecurring basis during the years ended December 31, 2019 and 2018 : Fair Value at Fair Value Measurements at Reporting Date Using Losses During the Year Ended Level 1 Level 2 Level 3 (in thousands) Impaired loans $ 10,007 $ — $ — $ 10,007 $ 7,519 $ 10,007 $ — $ — $ 10,007 $ 7,519 Fair Value at Fair Value Measurements at Reporting Date Using Losses During the Year Ended Level 1 Level 2 Level 3 (in thousands) Impaired loans $ 11,555 $ — $ — $ 11,555 $ 1,821 $ 11,555 $ — $ — $ 11,555 $ 1,821
Fair Value, by Balance Sheet Grouping	The following tables summarize carrying amounts and estimated fair values of selected financial instruments for the periods indicated: December 31, 2019 Carrying Fair Level 1 Level 2 Level 3 (in thousands) Assets Cash and due from banks $ 223,541 $ 223,541 $ 223,541 $ — $ — Interest-earning deposits with banks 24,132 24,132 24,132 — — Debt securities available for sale 3,746,142 3,746,172 — 3,746,172 — FHLB stock 48,120 48,120 — 48,120 — Loans held for sale 17,718 17,718 — 17,718 — Loans 8,659,497 8,883,865 — — 8,883,865 Interest rate contracts 19,144 19,144 — 19,144 — Interest rate collar 14,727 14,727 — 14,727 — Liabilities Time deposits $ 400,070 $ 397,736 $ — $ 397,736 $ — FHLB advances 953,469 952,762 — 952,762 — Repurchase agreements 64,437 64,437 — 64,437 — Subordinated debentures 35,277 35,491 — 35,491 — Interest rate contracts 19,145 19,145 — 19,145 — December 31, 2018 Carrying Fair Level 1 Level 2 Level 3 (in thousands) Assets Cash and due from banks $ 260,180 $ 260,180 $ 260,180 $ — $ — Interest-earning deposits with banks 17,407 17,407 17,407 — — Debt securities available for sale 3,167,448 3,167,448 248 3,167,200 — FHLB stock 25,960 25,960 — 25,960 — Loans held for sale 3,849 3,849 — 3,849 — Loans 8,308,142 8,316,946 — — 8,316,946 Interest rate contracts 7,033 7,033 — 7,033 — Liabilities Time deposits $ 414,443 $ 407,659 $ — $ 407,659 $ — FHLB advances 399,523 400,085 — 400,085 — Repurchase agreements 61,094 61,094 — 61,094 — Subordinated debentures 35,462 34,897 — 34,897 — Interest rate contracts 7,033 7,033 — 7,033 —

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	12 Months Ended
	Dec. 31, 2019
Earnings Per Share [Abstract]
Schedule of Basic and Diluted Earnings Per Share	The following table sets forth the computation of basic and diluted EPS for the periods indicated: Years Ended December 31, 2019 2018 2017 (in thousands except per share amounts) Basic EPS: Net income $ 194,451 $ 172,882 $ 112,828 Less: Earnings allocated to participating securities Preferred shares — — 3 Nonvested restricted shares 1,530 1,892 1,501 Earnings allocated to common shareholders $ 192,921 $ 170,990 $ 111,324 Weighted average common shares outstanding 71,999 72,385 59,882 Basic earnings per common share $ 2.68 $ 2.36 $ 1.86 Diluted EPS: Earnings allocated to common shareholders $ 192,921 $ 170,990 $ 111,324 Weighted average common shares outstanding 71,999 72,385 59,882 Dilutive effect of equity awards and warrants 33 5 6 Weighted average diluted common shares outstanding 72,032 72,390 59,888 Diluted earnings per common share $ 2.68 $ 2.36 $ 1.86 Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive 8 4 13

Share-Based Payments (Tables)

Share-Based Payments (Tables)	12 Months Ended
	Dec. 31, 2019
Share-based Payment Arrangement [Abstract]
Schedule of Nonvested Share Activity	A summary of changes in the Company’s nonvested shares and related information for the years ended December 31, 2019 , 2018 and 2017 is presented below: Shares Weighted Nonvested at January 1, 2017 818,755 $ 27.19 Granted 337,384 $ 38.51 Vested (253,509 ) $ 25.67 Forfeited (96,924 ) $ 28.97 Nonvested at December 31, 2017 805,706 $ 32.23 Granted 306,592 $ 41.47 Vested (237,146 ) $ 28.78 Forfeited (61,012 ) $ 35.92 Nonvested at December 31, 2018 814,140 $ 36.43 Granted 405,516 $ 35.08 Vested (268,253 ) $ 32.50 Forfeited (62,386 ) $ 37.12 Nonvested at December 31, 2019 889,017 $ 36.96
Schedule of Share-based Compensation, Stock Options, Activity	A summary of option activity under the Plan as of December 31, 2019 , and changes during the year then ended is presented below: Shares Weighted Weighted Aggregate Balance at December 31, 2018 5,514 $ 9.91 Expired (1,187 ) 9.91 Exercised (4,327 ) 9.91 Balance at December 31, 2019 — $ — 0 $ —

Income Tax (Tables)

Income Tax (Tables)	12 Months Ended
	Dec. 31, 2019
Income Tax Disclosure [Abstract]
Schedule of Components of Income Tax Expense (Benefit)	The components of income tax expense are as follows: Years Ended December 31, 2019 2018 2017 (in thousands) Current expense Federal $ 40,471 $ 33,400 $ 39,708 State 6,359 5,446 3,016 Total current tax expense $ 46,830 $ 38,846 $ 42,724 Deferred tax expense (benefit) Federal $ 60 $ (291 ) $ 21,524 State 270 399 907 Total deferred tax expense 330 108 22,431 Total $ 47,160 $ 38,954 $ 65,155
Schedule of Deferred Tax Assets and Liabilities	Significant components of the Company’s deferred tax assets and liabilities are as follows: December 31, 2019 2018 (in thousands) Deferred tax assets: ALLL $ 20,489 $ 20,578 Lease liability 14,776 — Deferred compensation 11,079 9,501 Stock options and restricted stock 2,016 1,850 OREO — 288 Nonaccrual interest 112 446 Unrealized loss on investment securities — 10,129 Net operating losses and credit carryforwards 4,136 5,356 Other 245 733 Total deferred tax assets 52,853 48,881 Deferred tax liabilities: Asset purchase tax basis difference (7,888 ) (7,229 ) Right of use asset (13,415 ) — FHLB stock dividends (789 ) (790 ) Deferred loan fees (4,097 ) (4,399 ) Unrealized gain on investment securities (10,091 ) — Purchase accounting (8,946 ) (9,245 ) Depreciation (3,152 ) (2,609 ) Cash flow hedge (3,452 ) — Other (100 ) (195 ) Total deferred tax liabilities (51,930 ) (24,467 ) Net deferred tax asset $ 923 $ 24,414
Schedule of Effective Income Tax Rate Reconciliation	A reconciliation of the Company’s effective income tax rate with the federal statutory tax rate is as follows: Years Ended December 31, 2019 2018 2017 Amount Percent Amount Percent Amount Percent (dollars in thousands) Income tax based on statutory rate $ 50,738 21 % $ 44,485 21 % $ 62,262 35 % Increase (decrease) resulting from: Tax exempt instruments (6,771 ) (3 )% (6,423 ) (3 )% (8,485 ) (5 )% Bank owned life insurance (1,963 ) (1 )% (1,261 ) (1 )% (3,351 ) (2 )% Acquisition costs — — % — — % 825 1 % Deferred tax asset revaluation — — % — — % 12,210 7 % State income tax, net of federal benefit 5,134 2 % 4,931 2 % 2,550 1 % Other, net 22 1 % (2,778 ) (1 )% (856 ) — % Income tax provision $ 47,160 20 % $ 38,954 18 % $ 65,155 37 %

Regulatory Capital Requiremen_2

Regulatory Capital Requirements (Tables)	12 Months Ended
	Dec. 31, 2019
Broker-Dealer, Net Capital Requirement, SEC Regulation [Abstract]
Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations	As of December 31, 2019 , the most recent notification from the FDIC categorized Columbia Bank as well-capitalized under the regulatory framework for prompt corrective action. To be categorized as well- capitalized, an institution must maintain minimum CET1 risk-based, Tier 1 risk-based, total risk-based and Tier 1 leverage ratios as set forth in the following table. There are no conditions or events since the notification that management believes have changed Columbia Bank’s category. The Company and its banking subsidiary’s actual capital amounts and ratios as of December 31, 2019 and 2018 are presented in the following table: Actual Minimum Required Minimum Required Minimum Required To Be Well Amount Ratio Amount Ratio Amount Ratio Amount Ratio Amount Ratio (dollars in thousands) December 31, 2019 CET1 Capital (to risk-weighted assets): The Company $ 1,317,202 12.45 % $ 476,260 4.50 % N/A N/A $ 740,849 7.00 % N/A N/A Columbia Bank $ 1,318,044 12.46 % $ 475,913 4.50 % N/A N/A $ 740,310 7.00 % $ 687,430 6.50 % Tier 1 Capital (to risk-weighted assets): The Company $ 1,317,202 12.45 % $ 635,014 6.00 % N/A N/A $ 899,603 8.50 % N/A N/A Columbia Bank $ 1,318,044 12.46 % $ 634,551 6.00 % N/A N/A $ 898,947 8.50 % $ 846,068 8.00 % Total Capital (to risk-weighted assets): The Company $ 1,439,877 13.60 % $ 846,685 8.00 % N/A N/A $ 1,111,274 10.50 % N/A N/A Columbia Bank $ 1,405,422 13.29 % $ 846,068 8.00 % N/A N/A $ 1,110,464 10.50 % $ 1,057,585 10.00 % Tier 1 Capital Leverage (to average assets): The Company $ 1,317,202 10.17 % $ 517,938 4.00 % N/A N/A $ 517,938 4.00 % N/A N/A Columbia Bank $ 1,318,044 10.22 % $ 515,797 4.00 % N/A N/A $ 515,797 4.00 % $ 644,746 5.00 % December 31, 2018 CET1 Capital (to risk-weighted assets): The Company $ 1,253,394 12.74 % $ 442,717 4.50 % $ 627,182 6.38 % $ 688,670 7.00 % N/A N/A Columbia Bank $ 1,274,317 12.96 % $ 442,552 4.50 % $ 626,948 6.38 % $ 688,414 7.00 % $ 639,241 6.50 % Tier 1 Capital (to risk-weighted assets): The Company $ 1,253,394 12.74 % $ 590,289 6.00 % $ 774,754 7.88 % $ 836,243 8.50 % N/A N/A Columbia Bank $ 1,274,317 12.96 % $ 590,069 6.00 % $ 774,465 7.88 % $ 835,931 8.50 % $ 786,759 8.00 % Total Capital (to risk-weighted assets): The Company $ 1,376,555 13.99 % $ 787,052 8.00 % $ 971,517 9.88 % $ 1,033,006 10.50 % N/A N/A Columbia Bank $ 1,362,016 13.85 % $ 786,759 8.00 % $ 971,155 9.88 % $ 1,032,621 10.50 % $ 983,448 10.00 % Tier 1 Capital Leverage (to average assets): The Company $ 1,253,394 10.24 % $ 489,399 4.00 % $ 489,399 4.00 % $ 489,399 4.00 % N/A N/A Columbia Bank $ 1,274,317 10.42 % $ 489,254 4.00 % $ 489,254 4.00 % $ 489,254 4.00 % $ 611,567 5.00 %

Parent Company Financial Info_2

Parent Company Financial Information (Tables)	12 Months Ended
	Dec. 31, 2019
Condensed Financial Information Disclosure [Abstract]
Condensed Balance Sheets - Parent Company Only	Condensed Balance Sheets—Parent Company Only December 31, 2019 2018 (in thousands) Assets Cash $ 6,088 $ 945 Interest-earning deposits 21,717 7,226 Total cash and cash equivalents 27,805 8,171 Investment in banking subsidiary 2,156,039 2,049,855 Investment in other subsidiaries 5,671 5,312 Goodwill 4,729 4,729 Other assets 1,675 1,595 Total assets $ 2,195,919 $ 2,069,662 Liabilities and Shareholders’ Equity Subordinated debentures $ 35,277 $ 35,462 Other liabilities 680 551 Total liabilities 35,957 36,013 Shareholders’ equity 2,159,962 2,033,649 Total liabilities and shareholders’ equity $ 2,195,919 $ 2,069,662
Condensed Statements of Income - Parent Company Only	Condensed Statements of Income—Parent Company Only Years Ended December 31, 2019 2018 2017 (in thousands) Income Dividend from banking subsidiary $ 168,000 $ 85,250 $ 66,800 Interest-earning deposits 100 12 2 Other income 68 56 8 Total income 168,168 85,318 66,810 Expense Compensation and employee benefits 791 978 732 Subordinated debentures interest expense 1,871 1,871 304 Other borrowings interest expense — 4 60 Other expense 2,111 2,058 3,090 Total expenses 4,773 4,911 4,186 Income before income tax benefit and equity in undistributed earnings of subsidiaries 163,395 80,407 62,624 Income tax benefit (967 ) (1,017 ) (548 ) Income before equity in undistributed earnings of subsidiaries 164,362 81,424 63,172 Equity in undistributed earnings of subsidiaries 30,089 91,458 49,656 Net income $ 194,451 $ 172,882 $ 112,828
Condensed Statements of Cash Flows - Parent Company Only	Condensed Statements of Cash Flows—Parent Company Only Years Ended December 31, 2019 2018 2017 (in thousands) Operating Activities Net income $ 194,451 $ 172,882 $ 112,828 Adjustments to reconcile net income to net cash provided by operating activities: Equity in undistributed earnings of subsidiaries (30,089 ) (91,458 ) (49,656 ) Stock-based compensation expense 9,271 8,354 7,745 Net changes in other assets and liabilities (133 ) 1,622 1,672 Net cash provided by operating activities 173,500 91,400 72,589 Investing Activities Net cash paid in business combinations — — (580 ) Net cash used in investing activities — — (580 ) Financing Activities Common stock dividends (102,265 ) (83,459 ) (51,308 ) Repayment of junior subordinated debentures — (8,248 ) (6,186 ) Cash settlement of acquired equity awards — — (7,345 ) Purchase and retirement of common stock (2,792 ) (2,677 ) (2,299 ) Purchase of treasury shares (50,834 ) — — Proceeds from exercise of stock options 2,025 1,857 1,980 Net cash used in financing activities (153,866 ) (92,527 ) (65,158 ) Increase (decrease) in cash and cash equivalents 19,634 (1,127 ) 6,851 Cash and cash equivalents at beginning of year 8,171 9,298 2,447 Cash and cash equivalents at end of year $ 27,805 $ 8,171 $ 9,298 Supplemental disclosure of noncash investing and financing activities Share-based consideration issued in business combinations $ — $ — $ 636,385

Summary Of Quarterly Financia_2

Summary Of Quarterly Financial Information (Unaudited) (Tables)	12 Months Ended
	Dec. 31, 2019
Quarterly Financial Information Disclosure [Abstract]
Schedule of Quarterly Financial Information	Quarterly financial information for the years ended December 31, 2019 and 2018 is summarized as follows: Fourth Third Second First Year Ended (in thousands, except per share amounts) 2019 Total interest income $ 133,109 $ 132,533 $ 135,422 $ 128,888 $ 529,952 Total interest expense 8,292 10,083 10,306 7,866 36,547 Net interest income 124,817 122,450 125,116 121,022 493,405 Provision for loan and lease losses 1,614 299 218 1,362 3,493 Noninterest income 21,807 28,030 25,648 21,696 97,181 Noninterest expense 86,978 87,076 86,728 84,700 345,482 Income before income taxes 58,032 63,105 63,818 56,656 241,611 Provision for income taxes 11,903 12,378 12,094 10,785 47,160 Net income $ 46,129 $ 50,727 $ 51,724 $ 45,871 $ 194,451 Per common share (1) Earnings (basic) $ 0.64 $ 0.70 $ 0.71 $ 0.63 $ 2.68 Earnings (diluted) $ 0.64 $ 0.70 $ 0.71 $ 0.63 $ 2.68 2018 Total interest income $ 129,801 $ 127,575 $ 120,549 $ 119,144 $ 497,069 Total interest expense 5,913 4,779 3,875 3,663 18,230 Net interest income 123,888 122,796 116,674 115,481 478,839 Provision for loan and lease losses 1,789 3,153 3,975 5,852 14,769 Noninterest income 20,402 21,019 23,692 23,143 88,256 Noninterest expense 87,019 82,841 84,643 85,987 340,490 Income before income taxes 55,482 57,821 51,748 46,785 211,836 Provision for income taxes 10,734 11,406 9,999 6,815 38,954 Net income $ 44,748 $ 46,415 $ 41,749 $ 39,970 $ 172,882 Per common share (1) Earnings (basic) $ 0.61 $ 0.63 $ 0.57 $ 0.55 $ 2.36 Earnings (diluted) $ 0.61 $ 0.63 $ 0.57 $ 0.55 $ 2.36 __________ (1) Due to averaging of shares, quarterly EPS may not add up to the totals reported for the full year.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	12 Months Ended
	Dec. 31, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table Text Block]	The following table shows the disaggregation of revenue from contracts with customers for the period indicated: Years Ended December 31, 2019 2018 (in thousands) Noninterest income: Revenue from contracts with customers: Deposit account and treasury management fees $ 35,695 $ 36,072 Card revenue 15,198 19,719 Financial services and trust revenue 12,799 12,135 Total revenue from contracts with customers 63,692 67,926 Other sources of noninterest income 33,489 20,330 Total noninterest income $ 97,181 $ 88,256

Summary of Significant Accoun_3

Summary of Significant Accounting Policies (Details)	12 Months Ended
	Dec. 31, 2019USD ($)location	Jan. 01, 2020USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)	Dec. 31, 2016USD ($)
Accounting Policies [Line Items]
Number Of Branch Locations | location	146
FHLB membership stock purchase requirement cap	$ 10,000,000
Federal Home Loan Bank stock, par value	100
Loans and Leases Receivable, Nonaccrual Loans Considered Impaired	500,000
Loans and Leases Receivable, Loans Evaluated For Impairment On Quarterly Basis, Outstanding	$ 500,000
Number Of Days Used To Determine Treatment As Cash Equivalent	90 days
Number of Days of Delinquency at Which Loans Are Categorized As Non Accrual Status	90 days
Core Deposits [Member]
Accounting Policies [Line Items]
Estimated life of CDI, in years	10 years
WASHINGTON
Accounting Policies [Line Items]
Number Of Branch Locations | location	71
OREGON
Accounting Policies [Line Items]
Number Of Branch Locations | location	61
IDAHO
Accounting Policies [Line Items]
Number Of Branch Locations | location	14
Vehicles [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P5Y
Minimum [Member] | Building and Building Improvements [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P5Y
Minimum [Member] | Furniture and Fixtures [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P3Y
Minimum [Member] | Software [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P3Y
Maximum [Member] | Building and Building Improvements [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P39Y
Maximum [Member] | Furniture and Fixtures [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P7Y
Maximum [Member] | Software [Member]
Accounting Policies [Line Items]
Property, Plant and Equipment, Estimated Useful Lives	P5Y
Accounting Standards Update 2016-02 [Member]
Accounting Policies [Line Items]
Change in other assets due to adoption of new ASU	$ 49,200,000
Change in other liabilities due to adoption of new ASU	48,200,000
Cumulative Effect of New Accounting Principle in Period of Adoption			$ (782,000)
Accounting Standards Update 2016-02 [Member] | Retained Earnings [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption			$ (782,000)
Accounting Standards Update 2018-02 [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ 0
Accounting Standards Update 2018-02 [Member] | Retained Earnings [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					(4,082,000)
Accounting Standards Update 2016-09 [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					(67,000)
Accounting Standards Update 2016-09 [Member] | Retained Earnings [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					117,000
Accounting Standards Update 2016-09 [Member] | Common Stock [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					$ (184,000)
Accounting Standards Update 2016-01 [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 0
Accounting Standards Update 2016-01 [Member] | Retained Earnings [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 157,000
Accounting Standards Update 2018-15 [Member]
Accounting Policies [Line Items]
Change in other assets due to adoption of new ASU	1,500,000
Accounting Standards Update 2016-13 [Member]
Accounting Policies [Line Items]
Change in allowance for credit loss due to adoption of new ASU		$ 1,600,000
Change in allowance for unfunded commitments and letters of credit due to adoption of new ASU		$ 1,600,000
Accounting Standards Update 2016-13 [Member] | Retained Earnings [Member]
Accounting Policies [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption	2,500,000
Designated as Hedging Instrument [Member] | Interest rate collar [Domain]
Accounting Policies [Line Items]
Derivative, Notional Amount	$ 500,000,000

Business Combinations (Details)

Business Combinations (Details) - USD ($) $ / shares in Units, $ in Thousands	Nov. 01, 2017	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Cost of Acquired Entity, Purchase Price, Total	$ 637,103
Business Combination, Acquisition Related Costs		$ 0	$ 8,661
Business Acquisition, Effective Date of Acquisition	Nov. 1, 2017
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Cash and Equivalents	$ 81,190
Business Acquisition, Purchase Price Allocation, Current Assets, Marketable Securities	449,291
Business Acquisition, Purchase Price Allocation, FHLB Stock	7,084
Business Combination, Acquired Receivable, Fair Value	1,873,987
Business Acquisition, Purchase Price Allocation, Accrued Interest Receivable	7,827
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	27,343
Business Acquisition, Purchase Price Allocation, Other Real Estate Owned	10,279
Business Combination, Purchase Price Allocation, Amortizable Intangible Assets	46,875
Business Combination, Purchase Price Allocation, Other Assets	50,638
Business Acquisition, Purchase Price Allocation, Liabilities, Deposits	(2,118,982)
Business Combination, Purchase Price Allocation, Federal Home Loan bank advances	101,127
Business Combination, Purchase Price Allocation, Subordinated Debt	(35,678)
Business combination, purchase price allocation, securities sold under agreements to repurchase	(1,617)
Business Acquisition, Purchase Price Allocation, Other Noncurrent Liabilities	(28,653)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	254,023
Business Combination, Purchase Price Allocation, Goodwill Amount	$ 383,080
Business Acquisition, Pro Forma Revenue				$ 571,944
Business Acquisition, Pro Forma Net Income (Loss)				$ 149,859
Business Acquisition, Pro Forma Earnings Per Share, Basic				$ 2.23
Business Acquisition, Pro Forma Earnings Per Share, Diluted				$ 2.23
Intermountain Community Bancorp [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs				$ 17,196
Compensation and employee benefits [Member] | Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs		0	3,620
Compensation and employee benefits [Member] | Intermountain Community Bancorp [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs				8,014
Occupancy [Member] | Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs		0	1,619
Occupancy [Member] | Intermountain Community Bancorp [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs				1,912
Advertising and promotion [Member] | Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs		0	537	467
Data processing [Member] | Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs		0	963
Data processing [Member] | Intermountain Community Bancorp [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs				1,555
Legal and professional fees [Member] | Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs		0	1,028
Legal and professional fees [Member] | Intermountain Community Bancorp [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs				4,618
Other noninterest expenses [Member] | Pacific Continental [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs		$ 0	$ 894
Other noninterest expenses [Member] | Intermountain Community Bancorp [Member]
Business Acquisition [Line Items]
Business Combination, Acquisition Related Costs				$ 630

Business Combinations narrative

Business Combinations narrative (Details) - Pacific Continental [Member] - USD ($) $ in Thousands	Nov. 01, 2017	Dec. 31, 2019	Dec. 31, 2018
Business Acquisition [Line Items]
Business Combination, Purchase Price Allocation, Junior Subordinated Debentures	$ (14,434)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Liabilities	(2,300,491)
Business Combination, Purchase Price Allocation, Goodwill Amount	$ 383,080
Business Acquisition, Effective Date of Acquisition	Nov. 1, 2017
Business Combination, Cost of Acquired Entity, Purchase Price, Total	$ 637,103
Business Combination, Acquired Receivable, Fair Value	1,873,987
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	254,023
Business Combination, Purchase Price Allocation, Amortizable Intangible Assets	46,875
Business Combination, Acquisition Related Costs		$ 0	$ 8,661
Business Combination, Purchase Price Allocation, Other Assets	50,638
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Assets	2,554,514
Business Acquisition, Purchase Price Allocation, Liabilities, Deposits	$ 2,118,982
Business Acquisition, Percentage of Voting Interests Acquired	100.00%
Business Combination, Purchase Price Allocation, Federal Home Loan bank advances	$ (101,127)

Cash and Cash Equivalents (Deta

Cash and Cash Equivalents (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Federal Reserve Bank [Member]
Restricted Cash and Cash Equivalents Items [Line Items]
Restricted Cash and Cash Equivalents	$ 84.9	$ 110.2

Securities (Securities Availabl

Securities (Securities Available for Sale) (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		$ 3,703,096	$ 3,210,615
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		63,486	12,799
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		(20,440)	(55,966)
Securities available for sale		3,746,142	3,167,448
Debt Securities, Available-for-sale, Amortized Cost		3,703,096
Debt Securities, Available-for-sale		3,746,142	3,167,448
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost	[1]	2,864,949	2,045,728
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax	[1]	47,223	8,473
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax	[1]	(19,222)	(40,846)
Securities available for sale	[1]	2,892,950	2,013,355
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Amortized Cost	[1]	194,563	176,793
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax	[1]	2,476	763
Debt Securities, Available-for-sale, Accumulated Gross Unrealized Loss, before Tax	[1]	(989)	(2,621)
Debt Securities, Available-for-sale	[1]	196,050	174,935
State and Municipal Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		478,366	579,755
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		10,660	2,328
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		(224)	(7,760)
Securities available for sale		488,802	574,323
U.S. Government Agency and Government-Sponsored Enterprise Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost		165,218	408,088
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax		3,127	1,235
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax		(5)	(4,736)
Securities available for sale		$ 168,340	404,587
US Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Amortized Cost			251
Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax			0
Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax			(3)
Securities available for sale			$ 248
[1]	Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation.

Securities (Schedule of Contrac

Securities (Schedule of Contractual Maturities of Investment Securities Available for Sale) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Abstract]
Due within one year, Amortized Cost	$ 77,363
Due after one year through five years, Amortized Cost	416,556
Due after five years through ten years, Amortized Cost	2,007,225
Due after ten years, Amortized Cost	1,201,952
Total investment securities available-for-sale, Amortized Cost	3,703,096
Due within one year, Fair Value	77,538
Due after one year through five years, Fair Value	421,363
Due after five years through ten years, Fair Value	2,041,751
Due after ten years, Fair Value	1,205,490
Total investment securities available-for-sale, Fair Value	$ 3,746,142	$ 3,167,448

Securities (Carrying Value of S

Securities (Carrying Value of Securities Pledged as Collateral) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 588,573	$ 467,138
To secure public funds [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	323,055	276,343
To secure borrowings [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	111,488	52,303
Other Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Debt Securities, Available-for-sale, Restricted	$ 154,030	$ 138,492

Securities (Summary of Gross Un

Securities (Summary of Gross Unrealized Losses and Fair Value of the Investments with Unrealized Losses) (Details) $ in Thousands		12 Months Ended
		Dec. 31, 2019USD ($)security	Dec. 31, 2018USD ($)		Dec. 31, 2017USD ($)
Debt Securities, Available-for-sale [Line Items]
Equity Securities, FV-NI, Gain (Loss)	[1]	$ 0	$ (195)		$ 0
Less than 12 Months Fair Value		1,157,774	276,306
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Instant		(13,446)	(1,598)
12 Months or More Fair Value		521,420	1,873,565
12 Months or More Unrealized Losses		(6,994)	(54,368)
Total Fair Value		1,679,194	2,149,871
Total Unrealized Losses		$ (20,440)	(55,966)
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security		243
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security		162
Less than 12 Months Fair Value	[2]	$ 1,055,903	114,551
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Instant	[2]	(12,424)	(750)
12 Months or More Fair Value	[2]	491,539	1,207,020
12 Months or More Unrealized Losses	[2]	(6,798)	(40,096)
Total Fair Value	[2]	1,547,442	1,321,571
Total Unrealized Losses	[2]	$ (19,222)	(40,846)
Asset-backed Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security		18
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security		6
Less than 12 Months Fair Value	[2]	$ 89,508	40,071
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Instant	[2]	(880)	(222)
12 Months or More Fair Value	[2]	6,799	94,367
12 Months or More Unrealized Losses	[2]	(109)	(2,399)
Total Fair Value	[2]	96,307	134,438
Available-for-sale Securities, Continuous Unrealized Loss Position, Accumulated Loss	[2]	$ (989)	(2,621)
State and Municipal Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security		24
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security		14
Less than 12 Months Fair Value		$ 12,363	106,292
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Instant		(142)	(581)	[2]
12 Months or More Fair Value		12,587	280,496
12 Months or More Unrealized Losses		(82)	(7,179)
Total Fair Value		24,950	386,788
Total Unrealized Losses		$ (224)	(7,760)
U.S. Government Agency and Government-Sponsored Enterprise Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security		3
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security		3
Less than 12 Months Fair Value		$ 0	15,392
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Instant		0	(45)
12 Months or More Fair Value		10,495	291,435
12 Months or More Unrealized Losses		(5)	(4,691)
Total Fair Value		10,495	306,827
Total Unrealized Losses		$ (5)	(4,736)
US Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions | security		0
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year | security		0
Less than 12 Months Fair Value			0
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss, Instant			0
12 Months or More Fair Value			247
12 Months or More Unrealized Losses			(3)
Total Fair Value			247
Total Unrealized Losses			$ (3)
[1]	Other securities losses, net includes net unrealized loss activity associated with equity securities.
[2]	Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation.

Securities (Narrative) (Details

Securities (Narrative) (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)issuancesecurity	Dec. 31, 2018USD ($)	Dec. 31, 2017USD ($)
Debt Securities, Available-for-sale [Line Items]
Number Of Issuances Of Securities Exceeding Shareholders Equity Threshold | issuance	0
Proceeds from Sale of Debt Securities, Available-for-sale | $	$ 259,554	$ 32,330	$ 30,403
US Government Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	0
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	0
Other Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Issuances Of Securities Exceeding Shareholders Equity Threshold, Percent	10.00%
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	243
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	162
Municipal Bonds [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	24
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	14
US Government Corporations and Agencies Securities [Member]
Debt Securities, Available-for-sale [Line Items]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	3
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Greater than or Equal to One Year	3

Securities Securities (Summary

Securities Securities (Summary of Gross Realized Gains and Losses) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Investments, Debt and Equity Securities [Abstract]
Proceeds from Sale of Debt Securities, Available-for-sale		$ 259,554	$ 32,330	$ 30,403
Available-for-sale Securities, Gross Realized Gains		3,357	235	111
Available-for-sale Securities, Gross Realized Losses		(1,225)	(129)	(122)
Equity Securities, FV-NI, Gain (Loss)	[1]	0	195	0
Debt and Equity Securities, Gain (Loss)		$ 2,132	$ (89)	$ (11)
[1]	Other securities losses, net includes net unrealized loss activity associated with equity securities.

Loans (Narrative) (Details)

Loans (Narrative) (Details) $ in Thousands, loan in Millions	12 Months Ended
	Dec. 31, 2019USD ($)contract	Dec. 31, 2018USD ($)loancontract	Dec. 31, 2017USD ($)contract
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	$ 33,060
Loans and Leases Receivable, Impaired, Interest Lost on Nonaccrual Loans	2,000	$ 3,600	$ 2,400
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing, Number of Loans	0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing, Number of Loans | loan		0
Loans and Leases Receivable, Nonaccrual of Interest, Commitments of Additional Funds	2,000	$ 2,100
Financing Receivable Modifications Additional Commitment To Lend	$ 1,100	$ 2,100
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | contract	1	0	0
Loans Receivable [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans pledged to collateralize Federal Home Loan Bank Advances	$ 3,240,000	$ 3,220,000
Commercial Loan [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans pledged to collateralize Federal Reserve Bank Borrowings	$ 151,300	$ 82,000

Loans (Analysis of Loan Portfol

Loans (Analysis of Loan Portfolio by Major Types of Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Credit Quality Indicator [Line Items]
Less: Net unearned income	$ (34,315)	$ (42,194)
Total loans, net of unearned income	8,743,465	8,391,511
Less: Allowance for loan and lease losses	(83,968)	(83,369)	$ (75,646)	$ (70,043)
Loans, net	8,659,497	8,308,142
Loans held for sale	17,718	3,849
Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	3,610,460	3,447,662
Real estate: One-to-four family residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	272,347	246,384
Less: Allowance for loan and lease losses	(607)	(593)	(701)	(599)
Commercial and Multifamily Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	4,238,173	3,908,937
Real Estate Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	4,510,520	4,155,321
One-to-Four Family Residential Construction [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	192,762	217,943
Commercial and Multifamily Residential Construction [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	163,103	284,928
Real Estate Construction Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	355,865	502,871
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	300,935	327,851
Less: Allowance for loan and lease losses	(4,455)	(5,301)	$ (5,163)	$ (3,534)
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	8,665,949	8,301,751
Less: Net unearned income	(34,315)	(42,194)
Total loans, net of unearned income	8,665,949	8,301,751
Less: Allowance for loan and lease losses	(81,124)	(79,758)
Loans, net	8,584,825	8,221,993
Loans held for sale	17,718	3,849
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	3,602,597	3,438,422
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	265,144	238,367
Total loans, net of unearned income	264,895	236,026
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	4,183,961	3,846,027
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real Estate Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	4,449,105	4,084,394
Loans, Excluding Purchased Credit Impaired Loans [Member] | One-to-Four Family Residential Construction [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	192,762	217,790
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential Construction [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	163,103	284,394
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real Estate Construction Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	355,865	502,184
Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	292,697	318,945
Total loans, net of unearned income	292,571	318,215
Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	82,272	96,285
Less: Net unearned income	0	0
Total loans, net of unearned income	77,516	89,760
Less: Allowance for loan and lease losses	(2,844)	(3,611)
Loans, net	74,672	86,149
Loans held for sale	0	0
Purchased Credit Impaired Loans [Member] | Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	8,083	9,672
Total loans, net of unearned income	7,863	9,240
Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	8,453	9,848
Total loans, net of unearned income	7,203	8,017
Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	56,752	66,340
Total loans, net of unearned income	54,212	62,910
Purchased Credit Impaired Loans [Member] | Real Estate Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	65,205	76,188
Total loans, net of unearned income	61,415	70,927
Purchased Credit Impaired Loans [Member] | One-to-Four Family Residential Construction [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	0	153
Total loans, net of unearned income	0	153
Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential Construction [Domain]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	0	507
Total loans, net of unearned income	0	534
Purchased Credit Impaired Loans [Member] | Real Estate Construction Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	0	660
Total loans, net of unearned income	0	687
Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross	8,984	9,765
Total loans, net of unearned income	$ 8,238	$ 8,906

Loans (Analysis of Nonaccrual L

Loans (Analysis of Nonaccrual Loans) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	$ 33,060
Unpaid Principal Balance Nonaccrual Loans	45,209	$ 65,358
Recorded Investment Nonaccrual Loans		54,842
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	2,018
Unpaid Principal Balance Nonaccrual Loans	2,355	3,149
Recorded Investment Nonaccrual Loans		2,949
Commercial business: Secured loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	26,615
Unpaid Principal Balance Nonaccrual Loans	38,278	45,072
Recorded Investment Nonaccrual Loans		35,504
Commercial business: Unsecured loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	359
Unpaid Principal Balance Nonaccrual Loans	360	9
Recorded Investment Nonaccrual Loans		9
Real estate: One-to-four family residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	591
Unpaid Principal Balance Nonaccrual Loans	632	1,178
Recorded Investment Nonaccrual Loans		1,158
Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	1,985
Unpaid Principal Balance Nonaccrual Loans	1,994	2,270
Recorded Investment Nonaccrual Loans		2,261
Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	205
Unpaid Principal Balance Nonaccrual Loans	206	3,062
Recorded Investment Nonaccrual Loans		2,721
Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	1,287
Unpaid Principal Balance Nonaccrual Loans	1,325	10,300
Recorded Investment Nonaccrual Loans		9,922
Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	0
Unpaid Principal Balance Nonaccrual Loans	0	318
Recorded Investment Nonaccrual Loans		318
Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	0
Unpaid Principal Balance Nonaccrual Loans	59	0
Recorded Investment Nonaccrual Loans		0
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	33,060	54,842
Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	2,018	2,949
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Secured loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	26,615	35,504
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Unsecured loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	359	9
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	591	1,158
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	1,985	2,261
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	205	2,721
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	1,287	9,922
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	0	318
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	0	0
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Income property [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	0	0
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Financing Receivable, Nonaccrual	$ 0	$ 0

Loans (Analysis of the Aged Loa

Loans (Analysis of the Aged Loan Portfolio) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	$ 33,060
Consumer [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	2,018
Commercial business: Secured loans [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	26,615
Commercial business: Unsecured loans [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	359
Real estate: One-to-four family residential [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	591
Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	1,985
Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	1,287
Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	0
Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	0
Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Nonaccrual Loans	205
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	8,609,241	$ 8,218,651
Total Past Due	23,648	28,258
Nonaccrual Loans	33,060	54,842
Financing Receivable, after Allowance for Credit Loss	8,665,949	8,301,751
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	88,389	194,912
Total Past Due	0	0
Nonaccrual Loans	0	0
Financing Receivable, after Allowance for Credit Loss	88,389	194,912
Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	290,174	314,008
Total Past Due	379	1,258
Nonaccrual Loans	2,018	2,949
Financing Receivable, after Allowance for Credit Loss	292,571	318,215
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Secured loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	3,422,313	3,267,709
Total Past Due	12,719	9,488
Nonaccrual Loans	26,615	35,504
Financing Receivable, after Allowance for Credit Loss	3,461,647	3,312,701
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Unsecured loans [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	128,852	111,868
Total Past Due	472	240
Nonaccrual Loans	359	9
Financing Receivable, after Allowance for Credit Loss	129,683	112,117
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	261,886	233,941
Total Past Due	2,418	927
Nonaccrual Loans	591	1,158
Financing Receivable, after Allowance for Credit Loss	264,895	236,026
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	300,580	283,416
Total Past Due	625	0
Nonaccrual Loans	1,985	2,261
Financing Receivable, after Allowance for Credit Loss	303,190	285,677
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	1,795,771	1,606,085
Total Past Due	4,287	1,744
Nonaccrual Loans	1,287	9,922
Financing Receivable, after Allowance for Credit Loss	1,801,345	1,617,751
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	1,364	4,099
Total Past Due	0	0
Nonaccrual Loans	0	318
Financing Receivable, after Allowance for Credit Loss	1,364	4,417
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	189,350	212,303
Total Past Due	951	93
Nonaccrual Loans	0	0
Financing Receivable, after Allowance for Credit Loss	190,301	212,396
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	2,057,359	1,910,505
Total Past Due	1,797	7,250
Nonaccrual Loans	205	2,721
Financing Receivable, after Allowance for Credit Loss	2,059,361	1,920,476
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Current Loans	73,203	79,805
Total Past Due	0	7,258
Nonaccrual Loans	0	0
Financing Receivable, after Allowance for Credit Loss	73,203	87,063
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	18,182	21,959
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	284	1,057
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Secured loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	7,684	5,864
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Unsecured loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	392	240
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	2,162	694
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	625	0
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	4,287	1,744
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	951	93
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	1,797	5,009
Financial Asset, 30 to 59 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	7,258
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	5,466	6,299
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	95	201
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Secured loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	5,035	3,624
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Unsecured loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	80	0
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	256	233
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	2,241
Financial Asset, 60 to 89 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Secured loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Unsecured loans [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	0	0
Financial Asset, Equal to or Greater than 90 Days Past Due [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Past Due [Line Items]
Total Past Due	$ 0	$ 0

Loans (Analysis of Impaired Loa

Loans (Analysis of Impaired Loans) (Details) - Loans, Excluding Purchased Credit Impaired Loans [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)Modifications	Dec. 31, 2018USD ($)Modifications	Dec. 31, 2017USD ($)Modifications
Financing Receivable, Modifications, Number of Contracts | Modifications	24	34	60
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 8,633,955	$ 8,252,647
Recorded Investment of Loans Individually Measured for Specific Impairment	31,994	49,104
Recorded Investment	483	3,326
Unpaid Principal Balance	637	3,584
Related Allowance	22	31
Impaired Financing Receivable, Average Recorded Investment	42,731	65,461	$ 40,650
Impaired Financing Receivable, Interest Income, Accrual Method	$ 452	$ 1,138	$ 971
Commercial business: Secured loans [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	11	12	10
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 3,437,564	$ 3,286,416
Recorded Investment of Loans Individually Measured for Specific Impairment	24,083	26,285
Recorded Investment	3,286	6,350
Unpaid Principal Balance	3,851	8,460
Related Allowance	93	2,023
Impaired Financing Receivable, Average Recorded Investment	24,682	39,701	$ 20,282
Impaired Financing Receivable, Interest Income, Accrual Method	$ 202	$ 81	$ 60
Commercial business: Unsecured loans [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 129,671	$ 112,097
Recorded Investment of Loans Individually Measured for Specific Impairment	12	20
Recorded Investment	12	20
Unpaid Principal Balance	12	20
Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	16	191	$ 5
Impaired Financing Receivable, Interest Income, Accrual Method	$ 1	$ 2	$ 0
Real estate: One-to-four family residential [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	1	0	3
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 264,513	$ 235,138
Recorded Investment of Loans Individually Measured for Specific Impairment	382	888
Recorded Investment	299	325
Unpaid Principal Balance	588	798
Related Allowance	5	8
Impaired Financing Receivable, Average Recorded Investment	665	748	$ 730
Impaired Financing Receivable, Interest Income, Accrual Method	$ 42	$ 42	$ 49
Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 300,973	$ 283,451
Recorded Investment of Loans Individually Measured for Specific Impairment	2,217	2,226
Recorded Investment	1,592	0
Unpaid Principal Balance	1,601	0
Related Allowance	312	0
Impaired Financing Receivable, Average Recorded Investment	2,606	2,371	$ 2,079
Impaired Financing Receivable, Interest Income, Accrual Method	$ 31	$ 34	$ 0
Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	1	1	1
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 2,059,361	$ 1,917,522
Recorded Investment of Loans Individually Measured for Specific Impairment	0	2,954
Recorded Investment	0	99
Unpaid Principal Balance	0	165
Related Allowance	0	1
Impaired Financing Receivable, Average Recorded Investment	1,121	3,284	$ 4,314
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 130	$ 51
Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 1,797,682	$ 1,605,042
Recorded Investment of Loans Individually Measured for Specific Impairment	3,663	12,709
Recorded Investment	3,663	3,231
Unpaid Principal Balance	5,233	4,666
Related Allowance	29	69
Impaired Financing Receivable, Average Recorded Investment	10,681	9,730	$ 5,335
Impaired Financing Receivable, Interest Income, Accrual Method	168	720	445
Real estate construction: One-to-four family residential: Land and acquisition [Member]
Recorded Investment of Loans Collectively Measured for Contingency Provision	1,364	4,417
Recorded Investment of Loans Individually Measured for Specific Impairment	0	0
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	0	0	3
Impaired Financing Receivable, Interest Income, Accrual Method	0	0	0
Real estate construction: One-to-four family residential: Residential construction [Member]
Recorded Investment of Loans Collectively Measured for Contingency Provision	190,301	212,396
Recorded Investment of Loans Individually Measured for Specific Impairment	0	0
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	0	484	309
Impaired Financing Receivable, Interest Income, Accrual Method	0	0	$ 0
Real estate construction: Commercial and multifamily residential: Income property [Member]
Recorded Investment of Loans Collectively Measured for Contingency Provision	88,389	194,912
Recorded Investment of Loans Individually Measured for Specific Impairment	0	0
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	$ 0	$ 0
Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 73,203	$ 87,063
Recorded Investment of Loans Individually Measured for Specific Impairment	0	0
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Related Allowance	0	0
Impaired Financing Receivable, Average Recorded Investment	0	3,240	$ 1,620
Impaired Financing Receivable, Interest Income, Accrual Method	$ 0	$ 0	$ 203
Consumer [Member]
Financing Receivable, Modifications, Number of Contracts | Modifications	11	21	42
Recorded Investment of Loans Collectively Measured for Contingency Provision	$ 290,934	$ 314,193
Recorded Investment of Loans Individually Measured for Specific Impairment	1,637	4,022
Impaired Financing Receivable, Average Recorded Investment	2,960	5,712	$ 5,973
Impaired Financing Receivable, Interest Income, Accrual Method	8	129	$ 163
Impaired Loans Without Recorded Allowance [Member]
Recorded Investment	22,659	35,753
Unpaid Principal Balance	30,813	40,716
Impaired Loans With Recorded Allowance [Member]
Recorded Investment	9,335	13,351
Unpaid Principal Balance	11,922	17,693
Related Allowance	461	2,132
Impaired Loans Without Recorded Allowance [Member]
Recorded Investment	1,154	696
Unpaid Principal Balance	1,310	704
Impaired Loans Without Recorded Allowance [Member] | Commercial business: Secured loans [Member]
Recorded Investment	20,797	19,935
Unpaid Principal Balance	28,658	24,404
Impaired Loans Without Recorded Allowance [Member] | Commercial business: Unsecured loans [Member]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Impaired Loans Without Recorded Allowance [Member] | Real estate: One-to-four family residential [Member]
Recorded Investment	83	563
Unpaid Principal Balance	182	575
Impaired Loans Without Recorded Allowance [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Recorded Investment	625	2,226
Unpaid Principal Balance	663	2,272
Impaired Loans Without Recorded Allowance [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Recorded Investment	0	2,855
Unpaid Principal Balance	0	3,011
Impaired Loans Without Recorded Allowance [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Recorded Investment	0	9,478
Unpaid Principal Balance	0	9,750
Impaired Loans Without Recorded Allowance [Member] | Real estate construction: One-to-four family residential: Land and acquisition [Member]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Impaired Loans Without Recorded Allowance [Member] | Real estate construction: One-to-four family residential: Residential construction [Member]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Impaired Loans Without Recorded Allowance [Member] | Real estate construction: Commercial and multifamily residential: Income property [Member]
Recorded Investment	0	0
Unpaid Principal Balance	0	0
Impaired Loans Without Recorded Allowance [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Recorded Investment	0	0
Unpaid Principal Balance	$ 0	$ 0

Loans Loans (Analysis of Troubl

Loans Loans (Analysis of Troubled Debt Restructurings) (Details) loan in Millions	12 Months Ended
	Dec. 31, 2019USD ($)Modificationscontract	Dec. 31, 2018USD ($)loanModificationscontract	Dec. 31, 2017USD ($)Modificationscontract
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable Modifications Additional Commitment To Lend	$ 1,100,000	$ 2,100,000
Financing Receivable, Troubled Debt Restructuring, Subsequent Default, Number of Contracts | contract	1	0	0
Financing Receivable, Troubled Debt Restructuring, Subsequent Default	$ 26,000	$ 0	$ 0
Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing, Number of Loans | loan		0
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	24	34	60
Pre-Modification Outstanding Recorded Investment	$ 7,348,000	$ 22,047,000	$ 18,122,000
Post-Modification Outstanding Recorded Investment	$ 7,348,000	$ 22,047,000	$ 18,122,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Secured loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	11	12	10
Pre-Modification Outstanding Recorded Investment	$ 6,642,000	$ 18,379,000	$ 5,655,000
Post-Modification Outstanding Recorded Investment	$ 6,642,000	$ 18,379,000	$ 5,655,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Commercial business: Unsecured loans [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 26,000
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 26,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	1	0	3
Pre-Modification Outstanding Recorded Investment	$ 45,000	$ 0	$ 583,000
Post-Modification Outstanding Recorded Investment	$ 45,000	$ 0	$ 583,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 687,000
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 687,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	1	1	1
Pre-Modification Outstanding Recorded Investment	$ 217,000	$ 891,000	$ 1,152,000
Post-Modification Outstanding Recorded Investment	$ 217,000	$ 891,000	$ 1,152,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 78,000
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 78,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	0	0	1
Pre-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 4,050,000
Post-Modification Outstanding Recorded Investment	$ 0	$ 0	$ 4,050,000
Loans, Excluding Purchased Credit Impaired Loans [Member] | Consumer [Member]
Financing Receivable, Troubled Debt Restructuring [Line Items]
Financing Receivable, Modifications, Number of Contracts | Modifications	11	21	42
Pre-Modification Outstanding Recorded Investment	$ 444,000	$ 2,777,000	$ 5,891,000
Post-Modification Outstanding Recorded Investment	$ 444,000	$ 2,777,000	$ 5,891,000

Loans Loans, analysis of purcha

Loans Loans, analysis of purchased credit impaired loans (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Allowance	$ 83,968	$ 83,369	$ 75,646	$ 70,043
Loans and Leases Receivable, Net Amount	8,659,497	8,308,142
Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,610,460	3,447,662
Real estate: One-to-four family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	272,347	246,384
Loans and Leases Receivable, Allowance	607	593	701	599
Commercial and Multifamily Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,238,173	3,908,937
Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,510,520	4,155,321
One-to-Four Family Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	192,762	217,943
Commercial and Multifamily Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	163,103	284,928
Real Estate Construction Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	355,865	502,871
Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	300,935	327,851
Loans and Leases Receivable, Allowance	4,455	5,301	$ 5,163	$ 3,534
Purchased Credit Impaired Loans [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	82,272	96,285
Valuation discount resulting from acquisition accounting	4,756	6,525
Loans and Leases Receivable, Allowance	2,844	3,611
Loans and Leases Receivable, Net Amount	74,672	86,149
Purchased Credit Impaired Loans [Member] | Commercial Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,083	9,672
Purchased Credit Impaired Loans [Member] | Real estate: One-to-four family residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,453	9,848
Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	56,752	66,340
Purchased Credit Impaired Loans [Member] | Real Estate Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	65,205	76,188
Purchased Credit Impaired Loans [Member] | One-to-Four Family Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	153
Purchased Credit Impaired Loans [Member] | Commercial and Multifamily Residential Construction [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	507
Purchased Credit Impaired Loans [Member] | Real Estate Construction Portfolio Segment [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	660
Purchased Credit Impaired Loans [Member] | Consumer [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	$ 8,984	$ 9,765

Loans Loans (Analysis of Purcha

Loans Loans (Analysis of Purchased Credit Impaired - Accretable Yield Rollforward) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Loans, Analysis of Purchased Credit Impaired Loans, Accretable Yield Rollforward [Abstract]
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield	$ 19,661	$ 21,949	$ 31,176	$ 45,191
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Accretion	(6,053)	(8,194)	(12,357)
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Disposals of Loans	(46)	387	158
Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Reclassifications from Nonaccretable Difference	$ 3,719	$ (646)	$ (1,500)

Allowance for Loan and Lease _3

Allowance for Loan and Lease Losses and Unfunded Commitments and Letters of Credit (Allowance for Noncovered Loan and Lease Losses) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				$ 83,369				$ 75,646	$ 83,369	$ 75,646	$ 70,043
Charge-offs									(15,215)	(18,555)	(16,660)
Recoveries									12,321	11,509	13,632
Provision for loan and lease losses	$ 1,614	$ 299	$ 218	1,362	$ 1,789	$ 3,153	$ 3,975	5,852	3,493	14,769	8,631
Balance at the end of year	83,968				83,369				83,968	83,369	75,646
Specific Reserve	461				2,132				461	2,132	2,360
General Allocation	83,507				81,237				83,507	81,237	73,286
Consumer [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				5,301				5,163	5,301	5,163	3,534
Charge-offs									(1,400)	(1,194)	(1,474)
Recoveries									930	1,180	1,187
Provision for loan and lease losses									(376)	152	1,916
Balance at the end of year	4,455				5,301				4,455	5,301	5,163
Specific Reserve	22				31				22	31	199
General Allocation	4,433				5,270				4,433	5,270	4,964
Purchased Credit Impaired Loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				3,611				6,907	3,611	6,907	10,515
Charge-offs									(3,319)	(4,862)	(6,812)
Recoveries									3,979	3,847	6,187
Provision for loan and lease losses									(1,427)	(2,281)	(2,983)
Balance at the end of year	2,844				3,611				2,844	3,611	6,907
Specific Reserve	0				0				0	0	0
General Allocation	2,844				3,611				2,844	3,611	6,907
Unallocated Financing Receivables [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				1,053				0	1,053	0	226
Charge-offs									0	0	0
Recoveries									0	0	0
Provision for loan and lease losses									(453)	1,053	(226)
Balance at the end of year	600				1,053				600	1,053	0
Specific Reserve	0				0				0	0	0
General Allocation	600				1,053				600	1,053	0
Commercial business: Secured loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				43,188				29,341	43,188	29,341	36,050
Charge-offs									(10,249)	(11,560)	(7,524)
Recoveries									2,755	3,024	4,283
Provision for loan and lease losses									7,381	22,383	(3,468)
Balance at the end of year	43,075				43,188				43,075	43,188	29,341
Specific Reserve	93				2,023				93	2,023	1,867
General Allocation	42,982				41,165				42,982	41,165	27,474
Commercial business: Unsecured loans [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				2,626				2,000	2,626	2,000	960
Charge-offs									(75)	(159)	(89)
Recoveries									350	403	553
Provision for loan and lease losses									184	382	576
Balance at the end of year	3,085				2,626				3,085	2,626	2,000
Specific Reserve	0				0				0	0	3
General Allocation	3,085				2,626				3,085	2,626	1,997
Real estate: One-to-four family residential [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				593				701	593	701	599
Charge-offs									(2)	0	(460)
Recoveries									242	408	568
Provision for loan and lease losses									(226)	(516)	(6)
Balance at the end of year	607				593				607	593	701
Specific Reserve	5				8				5	8	103
General Allocation	602				585				602	585	598
Real estate: Commercial and multifamily residential: Commercial land [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				3,947				4,265	3,947	4,265	1,797
Charge-offs									0	0	0
Recoveries									286	99	53
Provision for loan and lease losses									2,146	(417)	2,415
Balance at the end of year	6,379				3,947				6,379	3,947	4,265
Specific Reserve	312				0				312	0	0
General Allocation	6,067				3,947				6,067	3,947	4,265
Real estate: Commercial and multifamiIy residential: Income property [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				4,044				5,672	4,044	5,672	7,342
Charge-offs									0	(780)	(287)
Recoveries									320	912	498
Provision for loan and lease losses									2,062	(1,760)	(1,881)
Balance at the end of year	6,426				4,044				6,426	4,044	5,672
Specific Reserve	0				1				0	1	185
General Allocation	6,426				4,043				6,426	4,043	5,487
Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				4,533				5,459	4,533	5,459	6,439
Charge-offs									0	0	0
Recoveries									4	20	124
Provision for loan and lease losses									1,567	(946)	(1,104)
Balance at the end of year	6,104				4,533				6,104	4,533	5,459
Specific Reserve	29				69				29	69	3
General Allocation	6,075				4,464				6,075	4,464	5,456
Real estate construction: One-to-four family residential: Land and acquisition [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				549				963	549	963	316
Charge-offs									0	0	(14)
Recoveries									362	726	72
Provision for loan and lease losses									(799)	(1,140)	589
Balance at the end of year	112				549				112	549	963
Specific Reserve	0				0				0	0	0
General Allocation	112				549				112	549	963
Real estate construction: One-to-four family residential: Residential construction [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				5,536				3,709	5,536	3,709	669
Charge-offs									(170)	0	0
Recoveries									3,092	890	106
Provision for loan and lease losses									(3,982)	937	2,934
Balance at the end of year	4,476				5,536				4,476	5,536	3,709
Specific Reserve	0				0				0	0	0
General Allocation	4,476				5,536				4,476	5,536	3,709
Real estate construction: Commercial and multifamily residential: Income property [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				5,784				7,053	5,784	7,053	404
Charge-offs									0	0	0
Recoveries									1	0	1
Provision for loan and lease losses									(3,286)	(1,269)	6,648
Balance at the end of year	2,499				5,784				2,499	5,784	7,053
Specific Reserve	0				0				0	0	0
General Allocation	2,499				5,784				2,499	5,784	7,053
Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of year				$ 2,604				$ 4,413	2,604	4,413	1,192
Charge-offs									0	0	0
Recoveries									0	0	0
Provision for loan and lease losses									702	(1,809)	3,221
Balance at the end of year	3,306				2,604				3,306	2,604	4,413
Specific Reserve	0				0				0	0	0
General Allocation	$ 3,306				$ 2,604				$ 3,306	$ 2,604	$ 4,413

Allowance for Loan and Lease _4

Allowance for Loan and Lease Losses and Unfunded Commitments and Letters of Credit (Changes in the Allowance for Unfunded Commitments and Letters of Credit) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Allowance For Loan And Lease Losses And Unfunded Loan Commitments And Letters Of Credit
Beginning balance	$ 4,330	$ 3,130	$ 2,705
Net changes in the allowance for unfunded commitments and letters of credit	(900)	1,200	425
Ending balance	$ 3,430	$ 4,330	$ 3,130

Allowance for Loan and Lease _5

Allowance for Loan and Lease Losses and Unfunded Commitments and Letters of Credit (Analysis of Credit Quality of Loan Portfolio) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, net of unearned income	$ 8,743,465	$ 8,391,511
Loans and Leases Receivable, Allowance	83,968	83,369	$ 75,646	$ 70,043
Loans, net	8,659,497	8,308,142
Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,665,949	8,301,751
Loans, net of unearned income	8,665,949	8,301,751
Loans and Leases Receivable, Allowance	81,124	79,758
Loans, net	8,584,825	8,221,993
Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	82,272	96,285
Loans, net of unearned income	77,516	89,760
Valuation discount resulting from acquisition accounting	4,756	6,525
Loans and Leases Receivable, Allowance	2,844	3,611
Loans, net	74,672	86,149
Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,388,434	8,029,658
Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	71,807	94,337
Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	50,554	105,844
Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,459	0
Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	226,961	166,239
Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	9,006	1,948
Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	10
Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,610,460	3,447,662
Commercial Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,602,597	3,438,422
Commercial Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,083	9,672
Loans, net of unearned income	7,863	9,240
Commercial business: Secured loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	43,075	43,188	29,341	36,050
Commercial business: Secured loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,461,647	3,312,701
Commercial business: Secured loans [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	7,677	8,881
Commercial business: Secured loans [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	3,296,776	3,160,910
Commercial business: Secured loans [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	6,109	8,041
Commercial business: Secured loans [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	37,394	48,779
Commercial business: Secured loans [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	962	0
Commercial business: Secured loans [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	127,477	103,007
Commercial business: Secured loans [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	606	840
Commercial business: Secured loans [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	5
Commercial business: Secured loans [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial business: Secured loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial business: Secured loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial business: Unsecured loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	3,085	2,626	2,000	960
Commercial business: Unsecured loans [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	129,683	112,117
Commercial business: Unsecured loans [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	406	791
Commercial business: Unsecured loans [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	129,518	112,091
Commercial business: Unsecured loans [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	406	692
Commercial business: Unsecured loans [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	21
Commercial business: Unsecured loans [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial business: Unsecured loans [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	165	0
Commercial business: Unsecured loans [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	99
Commercial business: Unsecured loans [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	5
Commercial business: Unsecured loans [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial business: Unsecured loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Commercial business: Unsecured loans [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real Estate Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,510,520	4,155,321
Real Estate Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	4,449,105	4,084,394
Real Estate Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	65,205	76,188
Loans, net of unearned income	61,415	70,927
Real estate: One-to-four family residential [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	272,347	246,384
Loans and Leases Receivable, Allowance	607	593	701	599
Real estate: One-to-four family residential [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	265,144	238,367
Loans, net of unearned income	264,895	236,026
Real estate: One-to-four family residential [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,453	9,848
Loans, net of unearned income	7,203	8,017
Real estate: One-to-four family residential [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	264,051	234,416
Real estate: One-to-four family residential [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,351	9,633
Real estate: One-to-four family residential [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: One-to-four family residential [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: One-to-four family residential [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	844	1,610
Real estate: One-to-four family residential [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	102	215
Real estate: One-to-four family residential [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: One-to-four family residential [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: One-to-four family residential [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: One-to-four family residential [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamily residential: Commercial land [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	6,379	3,947	4,265	1,797
Real estate: Commercial and multifamily residential: Commercial land [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	303,190	285,677
Real estate: Commercial and multifamily residential: Commercial land [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	9,429	10,363
Real estate: Commercial and multifamily residential: Commercial land [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	283,254	276,348
Real estate: Commercial and multifamily residential: Commercial land [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,720	10,363
Real estate: Commercial and multifamily residential: Commercial land [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,344	5,082
Real estate: Commercial and multifamily residential: Commercial land [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	497	0
Real estate: Commercial and multifamily residential: Commercial land [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	18,592	4,247
Real estate: Commercial and multifamily residential: Commercial land [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	212	0
Real estate: Commercial and multifamily residential: Commercial land [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamily residential: Commercial land [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamily residential: Commercial land [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamily residential: Commercial land [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Income property [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	6,426	4,044	5,672	7,342
Real estate: Commercial and multifamiIy residential: Income property [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,059,361	1,920,476
Real estate: Commercial and multifamiIy residential: Income property [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	18,683	19,680
Real estate: Commercial and multifamiIy residential: Income property [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,014,233	1,876,925
Real estate: Commercial and multifamiIy residential: Income property [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	18,386	19,680
Real estate: Commercial and multifamiIy residential: Income property [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	5,658	36,998
Real estate: Commercial and multifamiIy residential: Income property [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Income property [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	39,470	6,553
Real estate: Commercial and multifamiIy residential: Income property [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	297	0
Real estate: Commercial and multifamiIy residential: Income property [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Income property [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Income property [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Income property [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Owner occupied [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	6,104	4,533	5,459	6,439
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,801,345	1,617,751
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	28,640	36,297
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,757,757	1,556,852
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	21,077	35,944
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	6,158	14,964
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	37,430	45,935
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	7,563	353
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate: Commercial and multifamiIy residential: Owner occupied [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real Estate Construction Portfolio Segment [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	355,865	502,871
Real Estate Construction Portfolio Segment [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	355,865	502,184
Real Estate Construction Portfolio Segment [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	660
Loans, net of unearned income	0	687
Real estate construction: One-to-four family residential: Land and acquisition [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	112	549	963	316
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,364	4,417
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		153
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	1,364	4,099
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		151
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	318
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		2
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: One-to-four family residential: Land and acquisition [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: One-to-four family residential: Residential construction [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	4,476	5,536	3,709	669
Real estate construction: One-to-four family residential: Residential construction [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	190,301	212,396
Real estate construction: One-to-four family residential: Residential construction [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	190,301	212,225
Real estate construction: One-to-four family residential: Residential construction [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: One-to-four family residential: Residential construction [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	171
Real estate construction: One-to-four family residential: Residential construction [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: One-to-four family residential: Residential construction [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Income property [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	2,499	5,784	7,053	404
Real estate construction: Commercial and multifamily residential: Income property [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	88,389	194,912
Real estate construction: Commercial and multifamily residential: Income property [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		507
Real estate construction: Commercial and multifamily residential: Income property [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	88,389	194,912
Real estate construction: Commercial and multifamily residential: Income property [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		507
Real estate construction: Commercial and multifamily residential: Income property [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Income property [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount		0
Real estate construction: Commercial and multifamily residential: Owner occupied [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Allowance	3,306	2,604	4,413	1,192
Real estate construction: Commercial and multifamily residential: Owner occupied [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	73,203	87,063
Real estate construction: Commercial and multifamily residential: Owner occupied [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	73,203	87,063
Real estate construction: Commercial and multifamily residential: Owner occupied [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Owner occupied [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Owner occupied [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Real estate construction: Commercial and multifamily residential: Owner occupied [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Consumer [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	300,935	327,851
Loans and Leases Receivable, Allowance	4,455	5,301	$ 5,163	$ 3,534
Consumer [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	292,697	318,945
Loans, net of unearned income	292,571	318,215
Consumer [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,984	9,765
Loans, net of unearned income	8,238	8,906
Consumer [Member] | Pass [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	289,588	313,817
Consumer [Member] | Pass [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	8,758	9,326
Consumer [Member] | Special Mention [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Consumer [Member] | Special Mention [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Consumer [Member] | Substandard [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	2,983	4,398
Consumer [Member] | Substandard [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	226	439
Consumer [Member] | Doubtful [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Consumer [Member] | Doubtful [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Consumer [Member] | Unlikely to be Collected Financing Receivable [Member] | Loans, Excluding Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	0	0
Consumer [Member] | Unlikely to be Collected Financing Receivable [Member] | Purchased Credit Impaired Loans [Member]
Financing Receivable, Credit Quality Indicator [Line Items]
Loans and Leases Receivable, Gross, Carrying Amount	$ 0	$ 0

Other Real Estate Owned (Summar

Other Real Estate Owned (Summary of Other Real Estate Owned) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Other Real Estate Owned [Line Items]
Balance, beginning of period	$ 6,019	$ 13,298
Transfers in	386	1,200
Valuation adjustments	(195)	(698)
Proceeds from sale of OREO property	6,455	7,261
Gain (loss) on sale of OREO, net	797	(520)
Balance, end of period	552	$ 6,019
Mortgage Loans in Process of Foreclosure, Amount	875
Real estate: One-to-four family residential [Member]
Other Real Estate Owned [Line Items]
Balance, end of period	$ 311

Premises and Equipment (Details

Premises and Equipment (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 243,329	$ 243,095
Less accumulated depreciation and amortization	(77,921)	(74,307)
Total	165,408	168,788
Depreciation and amortization expense	10,300	10,400	$ 9,800
Land [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	53,124	54,185
Building [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	107,371	108,890
Leasehold Improvements [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	28,459	27,859
Furniture and Fixtures [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	37,929	32,292
Vehicles [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	510	511
Software [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 15,936	$ 19,358

Goodwill and Intangible Asset_2

Goodwill and Intangible Assets (Schedule of Goodwill and Intangible Assets) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Goodwill and Intangible Assets [Line Items]
Indefinite-lived Intangible Assets (Excluding Goodwill)		$ 919	$ 919	$ 919
Intangible Assets, Net (Excluding Goodwill)		35,458	45,937	58,173
Goodwill and Intangible Assets [Roll Forward]
Total goodwill, beginning of period		765,842	765,842	382,762
Established through acquisitions	[1]	0	0	383,080
Total goodwill, end of period		765,842	765,842	765,842
Core deposit intangible, net, beginning of period		45,937
CDI current period amortization		(10,479)	(12,236)	(6,333)
Total core deposit intangible, end of period		35,458	45,937
Total goodwill and intangible assets, end of period		801,300	811,779	824,015
Core Deposits [Member]
Goodwill and Intangible Assets [Roll Forward]
Gross core deposit intangible balance, beginning of period		105,473	105,473	58,598
Accumulated amortization, beginning of period		(60,455)	(48,219)	(41,886)
Core deposit intangible, net, beginning of period		45,018	57,254	16,712
Established through acquisitions	[1]	0	0	46,875
CDI current period amortization		(10,479)	(12,236)	(6,333)
Total core deposit intangible, end of period		$ 34,539	$ 45,018	$ 57,254
Estimated life of CDI, in years		10 years
[1]	See Note 2, “Business Combinations,” for additional information regarding the goodwill and CDI related to the acquisition of Pacific Continental on November 1, 2017.

Goodwill and Intangible Asset_3

Goodwill and Intangible Assets (Summary of Estimated Future Amortization Expense of Core Deposit Intangibles) (Details) - Core Deposits [Member] $ in Thousands	Dec. 31, 2019USD ($)
Future Amortization Expense For Core Deposit Intangibles
2020	$ 8,724
2021	7,264
2022	5,880
2023	4,552
2024	$ 3,432

Leases (Details)

Leases (Details) - USD ($) $ in Thousands		Sep. 26, 2019	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Other Commitments [Line Items]
Operating Lease, Right-of-Use Asset			$ 57,226
Operating Lease, Liability			$ 63,030
Operating Lease, Weighted Average Remaining Lease Term			7 years 8 months 12 days
Operating Lease, Weighted Average Discount Rate, Percent			3.00%
Operating Lease, Payments			$ 11,200
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability			20,600
Operating Lease, Cost	[1]		10,851
Variable Lease, Cost			1,805
Sublease Income			(1,182)
Net lease, Cost			11,474
Operating Leases, Rent Expense, Sublease Rentals				$ 1,200	$ 791
Operating Leases, Rent Expense, Net				$ 9,600	$ 7,900
WASHINGTON
Other Commitments [Line Items]
Sale and Leaseback Transaction, Gain (Loss), Net		$ (5,900)
Bellevue Way [Domain] | WASHINGTON
Other Commitments [Line Items]
Sale Leaseback Transaction, Monthly Rental Payments			$ 19
[1]	Includes short-term lease costs, which are immaterial.

Future minimum payments for ope

Future minimum payments for operating leases (Details) $ in Thousands	Dec. 31, 2019USD ($)
Leases [Abstract]
2020	$ 11,105
2021	11,126
2022	10,689
2023	9,476
2024	6,980
Thereafter	21,866
Total future minimum lease payments	71,242
Amounts representing interest	8,212
Present value of minimum lease payments	$ 63,030

Leases Prior disclosed minimum

Leases Prior disclosed minimum lease payments schedule (Details) $ in Thousands	Dec. 31, 2018USD ($)
Leases ASC 840 [Abstract]
2019	$ 10,947
2020	9,766
2021	8,729
2022	8,102
2023	6,796
Thereafter	18,703
Total minimum payments	$ 63,043

Deposits (Details)

Deposits (Details) - USD ($) $ in Thousands		Dec. 31, 2019	Dec. 31, 2018
Deposits [Abstract]
Demand and other noninterest-bearing		$ 5,328,146	$ 5,227,216
Money market	[1]	2,322,644	2,294,125
Interest-bearing demand	[1]	1,150,437	1,084,863
Savings	[1]	882,050	889,849
Interest-bearing public funds, other than certificates of deposit	[1]	301,203	233,938
Certificates of deposit less than $250,000		218,764	243,849
Certificates of deposit greater than $250,000		151,995	89,473
Certificates of deposit insured by CDARS®		17,065	23,580
Brokered certificates of deposit		12,259	57,930
Reciprocal money market accounts		300,158	313,692
Subtotal		10,684,721	10,458,515
Deposits, Valuation Adjustment From Acquisition Accounting		(13)	(389)
Total deposits		10,684,708	10,458,126
Deposit Liabilities Reclassified as Loans Receivable		3,800	$ 4,000
Time Deposits, Fiscal Year Maturity [Abstract]
2020		313,241
2021		53,679
2022		19,346
2023		8,060
2024		5,593
Thereafter		151
Total		$ 400,070
[1]	Beginning in 2019, interest-bearing public funds, other than certificates of deposit, are presented separately in this table. Prior period amounts have been reclassified to conform to current period presentation.

Federal Home Loan Bank and Fe_3

Federal Home Loan Bank and Federal Reserve Bank Borrowings (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
FHLB Fixed Rate Advances, Maturities Summary [Abstract]
Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate of Amounts Due within One Year of Balance Sheet Date	1.82%
Federal Home Loan Bank, Advances, Maturities Summary, Fixed Rate, under One Year	$ 946,000
Federal Home Loan Bank, Advances, Maturities Summary, Average Interest Rate, One To Five Years From Balance Sheet Date	3.85%
FHLB Fixed Rate Advances, Over 1 through 5 years	$ 2,000
FHLB Fixed Rate Advances, Weighted Average Interest Rate, Due after 10 years	5.37%
FHLB Fixed Rate Advances, Due after 10 years	$ 5,000
FHLB Fixed Rate Advances, Total Amount before valuation adjustment	953,000	$ 399,000
Valuation adjustment from acquisition accounting	469
FHLB Fixed Rate Advances, Total Amount	953,469
Federal Home Loan Bank, Advances, Activity for Year [Abstract]
FHLB Advances	953,469	399,523	$ 11,579
Federal Home Loan Bank, Advances, Activity for Year, Average Balance of Agreements Outstanding	469,983	166,563	79,788
Maximum month-end balance during the year	$ 953,469	$ 399,523	$ 317,480
Weighted average rate during the year	2.42%	2.29%	1.33%
Weighted average rate at December 31	1.84%	2.68%	4.08%
FHLB Borrowing Capacity	$ 1,960,000	$ 1,620,000
Federal Reserve Bank, Advances, Activity for Year [Abstract]
Average balance during the year	99	14
Federal Reserve Bank borrowing capacity	$ 209,100	$ 107,100

Securities Sold Under Agreeme_2

Securities Sold Under Agreements to Repurchase (Details) $ in Millions	Dec. 31, 2019USD ($)
Available-for-sale Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets Sold under Agreements to Repurchase, Term, Carrying Amounts	$ 25
Assets Sold under Agreements to Repurchase, Term, Interest Rate	1.88%
Repurchase Agreements, Sweep [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Carrying amount of securities pledged as collateral	$ 76
Repurchase Agreements, Sweep [Member] | Available-for-sale Securities [Member]
Assets Sold under Agreements to Repurchase [Line Items]
Assets Sold under Agreements to Repurchase, Sweep, Carrying Amount	$ 64.4
Assets Sold under Agreements to Repurchase, Sweep, Interest rate	1.24%

Subordinated debentures (Detail

Subordinated debentures (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Nov. 01, 2017
Subordinated Borrowing [Line Items]
Subordinated Borrowing, Interest Rate	5.875%
Pacific Continental [Member]
Subordinated Borrowing [Line Items]
Business Combination, Purchase Price Allocation, Subordinated Debt		$ 35
Subordinated Debt [Member]
Subordinated Borrowing [Line Items]
Debt Instrument, Interest Rate Terms	4.715%

Revolving line of credit (Detai

Revolving line of credit (Details) $ in Thousands	Dec. 31, 2019USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 30,000
Line of Credit [Member]
Line of Credit Facility [Line Items]
Short-term Debt	$ 0

Derivatives and Balance Sheet_3

Derivatives and Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Derivative [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	$ 3,200
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)	15,322	$ 0
Gain (Loss) on Derivative Instruments, Net, Pretax	(1)	8	$ 16
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	64,437
Secured Borrowings, Gross, Difference, Amount	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, before Tax	595	0
Designated as Hedging Instrument [Member] | Interest rate collar [Domain]
Derivative [Line Items]
Derivative, Notional Amount	500,000
Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest rate collar [Domain]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	14,727	0
Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest rate collar [Domain]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	0	0
Not Designated as Hedging Instrument [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount	428,600	366,700
Not Designated as Hedging Instrument [Member] | Other Assets [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Derivative Asset, Fair Value, Gross Asset	19,144	7,033
Not Designated as Hedging Instrument [Member] | Other Liabilities [Member] | Interest Rate Contracts [Member]
Derivative [Line Items]
Derivative Liability, Fair Value, Gross Liability	19,145	$ 7,033
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member]
Derivative [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	64,437
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] | Maturity Overnight [Member]
Derivative [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	64,437
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] | Maturity Less than 30 Days [Member]
Derivative [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	0
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] | Maturity 30 to 90 Days [Member]
Derivative [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	0
U.S. Government Agency and Government-Sponsored Enterprise Mortgage-Backed Securities and Collateralized Mortgage Obligations [Member] | Maturity Greater than 90 Days [Member]
Derivative [Line Items]
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	$ 0

Derivatives and Balance Sheet_4

Derivatives and Balance Sheet Offsetting Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Balance Sheet Offsetting [Line Items]
Repurchase agreements, amounts offset in balance sheet	$ 0	$ 0
repurchase agreements, net amount presented in statement of financial position	64,437	61,094
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	(64,437)	(61,094)
securities sold under agreements to repurchase, amount not offset	0	0
Secured Borrowings, Gross Including Not Subject to Master Netting Arrangement	64,437
Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0	0
Derivative Asset	19,144	7,033
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	19,144	7,033
Derivative Liability, Gross Amounts Offset in Balance Sheets	0	0
Derivative Liability	19,145	7,033
Derivative, Collateral, Right to Reclaim Securities	(19,145)	(3,235)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0	3,798
Interest rate collar [Domain]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0
Derivative Asset	14,727
Derivative, Collateral, Obligation to Return Cash	(14,727)
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	0
Other Assets [Member] | Interest rate collar [Domain] | Designated as Hedging Instrument [Member]
Balance Sheet Offsetting [Line Items]
Derivative Asset, Fair Value, Gross Asset	14,727	0
Other Liabilities [Member] | Interest rate collar [Domain] | Designated as Hedging Instrument [Member]
Balance Sheet Offsetting [Line Items]
Derivative Liability, Fair Value, Gross Liability	0	0
Available-for-sale Securities [Member]
Balance Sheet Offsetting [Line Items]
Assets Sold under Agreements to Repurchase, Term, Carrying Amounts	25,000
Assets Sold under Agreements to Repurchase, Carrying Amount	$ 64,437	$ 61,094

Employee Benefit Plans (Details

Employee Benefit Plans (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)yearsperiodshares	Dec. 31, 2018USD ($)shares	Dec. 31, 2017USD ($)shares
Employee Benefit [Line Items]
Number of Look-back Period Under Employee Stock Purchase Plan | period	2
Look-back Period Under Employee Stock Purchase Plan	6 months
Discount On Common Stock Under Employee Stock Purchase Plan, Percent	10.00%
Stock Issued During Period, Shares, Employee Stock Purchase Plans | shares	57,201	50,750	38,387
Stock Issued During Period, Value, Employee Stock Purchase Plan	$ 2,100	$ 2,000	$ 1,500
Shares Available For Purchase Under Employee Stock Purchase Plan | shares	303,156
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Balance at beginning of year	$ 21,287	20,553
Change in actuarial loss	2,663	(31)
Benefit expense	1,930	1,701
Defined Benefit Plan, Benefit Obligation, Benefits Paid	966	936
Balance at end of year	$ 24,914	21,287	20,553
Pension Plan [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Requisite Service Period	1 month
Deferred Compensation Arrangement with Individual, Contribution To Plan By Employee, Percent Of Eligible Compensation	75.00%
Deferred Compensation Arrangement with Individual, Contribution Requirements, Matching Percent	50.00%
Deferred Compensation Arrangement with Individual, Contributions by Employer	$ 3,500	3,300	2,700
Pension Plan [Member] | Minimum [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Eligible Age | years	18
Pension Plan [Member] | Maximum [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Contribution Requirements, Percent Of Each Employee Compensation	3.00%
Deferred Profit Sharing [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Requisite Service Period	1 month
Deferred Compensation Arrangement with Individual, Contribution To Plan By Employee, Percent Of Eligible Compensation	75.00%
Deferred Compensation Arrangement with Individual, Contribution Requirements, Matching Percent	50.00%
Deferred Compensation Arrangement with Individual, Contributions by Employer	$ 7,300	7,000	5,700
Deferred Profit Sharing [Member] | Minimum [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Eligible Age | years	18
Deferred Profit Sharing [Member] | Maximum [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Contribution Requirements, Percent Of Each Employee Compensation	3.00%
ESP Plan [Member]
Employee Benefit [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date	90.00%
Unit Plans [Member]
Employee Benefit [Line Items]
Deferred Compensation Arrangement with Individual, Vesting Period	10
Deferred Compensation Arrangement with Individual, Benefit Period	10
Deferred Compensation Arrangement with Individual, Recorded Liability	$ 4,000	4,200
Deferred Compensation Arrangement with Individual, Compensation Expense	$ 415	$ 337	$ 452
SERP [Member]
Employee Benefit [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	3.34%	4.30%
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Normal Retirement Age | years	65
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Annual Cost Of Living Benefit Adjustment	2.00%
Defined Benefit Plan, Expected Future Benefit Payment [Abstract]
2020	$ 1,971
2021	1,116
2022	1,135
2023	1,239
2024	1,438
2025 through 2029	8,574
Total	$ 15,473

Commitments and Contingent Li_2

Commitments and Contingent Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Commitments to Extend Credit [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 2,670,000	$ 2,620,000
Standby Letters of Credit [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	25,700	28,300
Commercial Letter of Credit and other off-balance sheet liabilities [Member]
Loss Contingencies [Line Items]
Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability	$ 0	$ 0

Shareholders' Equity (Details)

Shareholders' Equity (Details) - $ / shares	Jan. 23, 2020	Oct. 24, 2019	Jul. 25, 2019	Apr. 25, 2019	Jan. 24, 2019
Class of Stock [Line Items]
Declared quarterly cash dividend		$ 0.28	$ 0.28	$ 0.28	$ 0.28
Common Stock, Special Cash Dividends, Per Share, Declared		$ 0	$ 0	$ 0.14	$ 0.14
Subsequent Event [Member]
Class of Stock [Line Items]
Declared quarterly cash dividend	$ 0.28
Common Stock, Special Cash Dividends, Per Share, Declared	$ 0.22

Shareholders' Equity Share repu

Shareholders' Equity Share repurchase (Details) - $ / shares shares in Millions	Jan. 23, 2020	Oct. 24, 2019	Jul. 25, 2019	Apr. 25, 2019	Jan. 24, 2019	Dec. 31, 2019
Class of Stock [Line Items]
Common Stock, Dividends, Per Share, Declared		$ 0.28	$ 0.28	$ 0.28	$ 0.28
Treasury Stock, Shares, Acquired						1.5
Treasury Stock Acquired, Average Cost Per Share						$ 35
Stock Repurchase Program, Remaining Number of Shares Authorized to be Repurchased						1.4
Subsequent Event [Member]
Class of Stock [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.28

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax		$ 40,367	$ (35,305)	$ (22,225)	$ (18,999)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		77,520	(13,401)	626
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	(1,848)	164	230
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		75,672	(13,237)	856
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax		33,038	(33,128)	(19,779)	(12,704)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		67,802	(13,425)	(3,391)
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	(1,636)	(81)	7
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		66,166	(13,506)	(3,384)
Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax		(3,974)	(2,177)	(2,446)	(6,295)
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		(2,042)	24	4,017
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	245	245	223
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		(1,797)	269	4,240
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax		11,303	0	0	0
Other Comprehensive Income (Loss), before Reclassifications, Net of Tax		11,760	0	0
Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax	[1]	(457)	0	0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent		$ 11,303	$ 0	0
Accounting Standards Update 2016-01 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Accounting Standards Update 2016-01 [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				(157)
Accounting Standards Update 2016-01 [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Accounting Standards Update 2016-01 [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				0
Accounting Standards Update 2016-01 [Member] | Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				(157)
Accounting Standards Update 2018-02 [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption					0
Accounting Standards Update 2018-02 [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				3,691
Accounting Standards Update 2018-02 [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				391
Accounting Standards Update 2018-02 [Member] | Accumulated Other Comprehensive Income [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption				$ 4,082	$ 4,082
[1]	See following table for details about these reclassifications.

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Income Amounts reclassified from Accumulated Other Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains (losses), net									$ 2,132	$ (89)	$ (11)
Income before income taxes	$ 58,032	$ 63,105	$ 63,818	$ 56,656	$ 55,482	$ 57,821	$ 51,748	$ 46,785	241,611	211,836	177,983
Income Tax Expense (Benefit)	(11,903)	(12,378)	(12,094)	(10,785)	(10,734)	(11,406)	(9,999)	(6,815)	(47,160)	(38,954)	(65,155)
Net income	$ 46,129	$ 50,727	$ 51,724	$ 45,871	$ 44,748	$ 46,415	$ 41,749	$ 39,970	194,451	172,882	112,828
Compensation and employee benefits									212,867	200,199	169,674
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Investment securities gains (losses), net									2,132	106	(11)
Income before income taxes									2,132	106	(11)
Income Tax Expense (Benefit)									(496)	(25)	4
Net income									1,636	81	(7)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes									(319)	(319)	(350)
Income Tax Expense (Benefit)									74	74	127
Net income									(245)	(245)	(223)
Compensation and employee benefits									(319)	(319)	(350)
Reclassification out of Accumulated Other Comprehensive Income [Member] | Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Income before income taxes									595	0	0
Income Tax Expense (Benefit)									(138)	0	0
Net income									457	0	0
Interest Rate Cash Flow Hedge Gain (Loss) Reclassified to Earnings, Net									$ 595	$ 0	0
Accounting Standards Update 2018-02 [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption												$ 0
Accounting Standards Update 2018-02 [Member] | Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption											(4,082)	$ (4,082)
Accounting Standards Update 2018-02 [Member] | Accumulated Net Unrealized Investment Gain (Loss) [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption											(3,691)
Accounting Standards Update 2018-02 [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cumulative Effect of New Accounting Principle in Period of Adoption											$ (391)

Fair Value Accounting and Mea_3

Fair Value Accounting and Measurement (Financial Assets And Liabilities Accounted for Fair Value On Recurring Basis) (Details) - USD ($)		Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Liabilities, Level 1 to Level 2 Transfers, Amount		$ 0	$ 0
Securities available for sale		3,746,142,000	3,167,448,000
Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		3,746,142,000	3,167,448,000
Other assets (Interest rate contracts)		19,144,000	7,033,000
Interest Rate Cash Flow Hedge Asset at Fair Value		14,727,000
Other liabilities (Interest rate contracts)		19,145,000	7,033,000
Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		0	248,000
Other assets (Interest rate contracts)		0	0
Interest Rate Cash Flow Hedge Asset at Fair Value		0
Other liabilities (Interest rate contracts)		0	0
Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		3,746,142,000	3,167,200,000
Other assets (Interest rate contracts)		19,144,000	7,033,000
Interest Rate Cash Flow Hedge Asset at Fair Value		14,727,000
Other liabilities (Interest rate contracts)		19,145,000	7,033,000
Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		0	0
Other assets (Interest rate contracts)		0	0
Interest Rate Cash Flow Hedge Asset at Fair Value		0
Other liabilities (Interest rate contracts)		0	0
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	2,892,950,000	2,013,355,000
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	0	0
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	2,892,950,000	2,013,355,000
U.S. Government Agency and Sponsored Enterprise Mortgage-Back Securities and Collateralized Mortgage Obligations [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	0	0
Asset-backed Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	196,050,000	174,935,000
Asset-backed Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	0	0
Asset-backed Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	196,050,000	174,935,000
Asset-backed Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale	[1]	0	0
State and Municipal Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		488,802,000	574,323,000
State and Municipal Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		488,802,000	574,323,000
State and Municipal Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		0	0
State and Municipal Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		488,802,000	574,323,000
State and Municipal Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		0	0
U.S. Government Agency [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		168,340,000	404,587,000
U.S. Government Agency [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		0	0
U.S. Government Agency [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		168,340,000	404,587,000
U.S. Government Agency [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale		$ 0	0
US Government Securities [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale			248,000
US Government Securities [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale			248,000
US Government Securities [Member] | Fair Value, Inputs, Level 1 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale			248,000
US Government Securities [Member] | Fair Value, Inputs, Level 2 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale			0
US Government Securities [Member] | Fair Value, Inputs, Level 3 [Member] | Fair Value, Recurring [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Securities available for sale			$ 0
[1]	Beginning in 2019, other asset-backed securities were presented separately in this table. Prior period amounts that were previously reported in U.S. government agency and government-sponsored enterprise mortgage-backed securities and collateralized mortgage obligations have been reclassified to conform to current period presentation.

Fair Value Accounting and Mea_4

Fair Value Accounting and Measurement (Financial Assets Accounted For Fair Value On Nonrecurring Basis) (Details) - Fair Value, Nonrecurring [Member] - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	$ 10,007	$ 11,555
Fair Value, Option, Changes in Fair Value, Gain (Loss)	7,519	1,821
Assets, Fair Value Disclosure	10,007	11,555
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	0	0
Assets, Fair Value Disclosure	0	0
Fair Value, Inputs, Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Impaired loans	10,007	11,555
Assets, Fair Value Disclosure	10,007	11,555
Impaired Loans [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	$ 7,519	$ 1,821

Fair Value Accounting and Mea_5

Fair Value Accounting and Measurement (Quantitative Information About Level 3 Fair Value Measurements) (Details) - Fair Value, Nonrecurring [Member] $ in Thousands	12 Months Ended
	Dec. 31, 2019USD ($)	Dec. 31, 2018USD ($)
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	$ 10,007	$ 11,555
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(7,519)	(1,821)
Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	10,007	11,555
Impaired Loans [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Fair Value, Option, Changes in Fair Value, Gain (Loss)	(7,519)	(1,821)
Uncollateralized [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans		$ 3,161
Uncollateralized [Member] | Valuation, Market Approach [Member] | Impaired Loans [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Measurement Input		0.0034
Uncollateralized [Member] | Valuation, Market Approach [Member] | Impaired Loans [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Measurement Input		0.0034
Uncollateralized [Member] | Valuation, Market Approach [Member] | Impaired Loans [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Measurement Input		0.0034
Collateral-Dependent [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired loans	$ 10,007	$ 8,394
Collateral-Dependent [Member] | Valuation, Market Approach [Member] | Impaired Loans [Member] | Minimum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Measurement Input	0	0
Collateral-Dependent [Member] | Valuation, Market Approach [Member] | Impaired Loans [Member] | Maximum [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Measurement Input	1	0.7004
Collateral-Dependent [Member] | Valuation, Market Approach [Member] | Impaired Loans [Member] | Weighted Average [Member] | Fair Value, Inputs, Level 3 [Member]
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Impaired Loans, Measurement Input	0.4968	0.0702

Fair Value Accounting and Mea_6

Fair Value Accounting and Measurement (Carrying Amounts and Estimated Fair Values of Selected Financial Instruments) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Interest-earning deposits with banks	$ 24,132	$ 17,407
Debt Securities, Available-for-sale	3,746,142	3,167,448
Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	223,541	260,180
Interest-earning deposits with banks	24,132	17,407
Debt Securities, Available-for-sale	3,746,172	3,167,448
FHLB stock	48,120	25,960
Loans held for sale	17,718	3,849
Loans	8,883,865	8,316,946
Interest rate contracts	19,144	7,033
Interest Rate Cash Flow Hedge Asset at Fair Value	14,727
Liabilities
Time Deposits	397,736	407,659
FHLB Advances	952,762	400,085
Repurchase agreements	64,437	61,094
Subordinated Debt Obligations, Fair Value Disclosure	35,491	34,897
Interest rate contracts	19,145	7,033
Reported Value Measurement [Member]
Assets
Cash and due from banks	223,541	260,180
Interest-earning deposits with banks	24,132	17,407
Debt Securities, Available-for-sale	3,746,142	3,167,448
FHLB stock	48,120	25,960
Loans held for sale	17,718	3,849
Loans	8,659,497	8,308,142
Interest rate contracts	19,144	7,033
Interest Rate Cash Flow Hedge Asset at Fair Value	14,727
Liabilities
Time Deposits	400,070	414,443
FHLB Advances	953,469	399,523
Repurchase agreements	64,437	61,094
Subordinated Debt Obligations, Fair Value Disclosure	35,277	35,462
Interest rate contracts	19,145	7,033
Fair Value, Inputs, Level 1 [Member] | Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	223,541	260,180
Interest-earning deposits with banks	24,132	17,407
Debt Securities, Available-for-sale	0	248
FHLB stock	0	0
Loans held for sale	0	0
Loans	0	0
Interest rate contracts	0	0
Interest Rate Cash Flow Hedge Asset at Fair Value	0
Liabilities
Time Deposits	0	0
FHLB Advances	0	0
Repurchase agreements	0	0
Subordinated Debt Obligations, Fair Value Disclosure	0	0
Interest rate contracts	0	0
Fair Value, Inputs, Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	0	0
Interest-earning deposits with banks	0	0
Debt Securities, Available-for-sale	3,746,172	3,167,200
FHLB stock	48,120	25,960
Loans held for sale	17,718	3,849
Loans	0	0
Interest rate contracts	19,144	7,033
Interest Rate Cash Flow Hedge Asset at Fair Value	14,727
Liabilities
Time Deposits	397,736	407,659
FHLB Advances	952,762	400,085
Repurchase agreements	64,437	61,094
Subordinated Debt Obligations, Fair Value Disclosure	35,491	34,897
Interest rate contracts	19,145	7,033
Fair Value, Inputs, Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Assets
Cash and due from banks	0	0
Interest-earning deposits with banks	0	0
Debt Securities, Available-for-sale	0	0
FHLB stock	0	0
Loans held for sale	0	0
Loans	8,883,865	8,316,946
Interest rate contracts	0	0
Interest Rate Cash Flow Hedge Asset at Fair Value	0
Liabilities
Time Deposits	0	0
FHLB Advances	0	0
Repurchase agreements	0	0
Subordinated Debt Obligations, Fair Value Disclosure	0	0
Interest rate contracts	$ 0	$ 0

Earnings Per Common Share (Sche

Earnings Per Common Share (Schedule of Basic and Diluted Earnings Per Share) (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Earnings Per Share, Basic, by Common Class, Including Two Class Method [Line Items]
Basic earnings allocated to common shareholders																	$ 192,921		$ 170,990		$ 111,324
Net income	$ 46,129		$ 50,727		$ 51,724		$ 45,871		$ 44,748		$ 46,415		$ 41,749		$ 39,970		194,451		172,882		112,828
Earnings allocated to participating securities - preferred shares																	0		0		3
Earnings allocated to participating securities - nonvested restricted shares																	$ 1,530		$ 1,892		$ 1,501
Weighted average common shares outstanding																	71,999		72,385		59,882
Basic earnings per common share	$ 0.64	[1]	$ 0.70	[1]	$ 0.71	[1]	$ 0.63	[1]	$ 0.61	[1]	$ 0.63	[1]	$ 0.57	[1]	$ 0.55	[1]	$ 2.68	[1]	$ 2.36	[1]	$ 1.86
Earnings allocated to common shareholders, Diluted																	$ 192,921		$ 170,990		$ 111,324
Weighted average number of common shares outstanding																	71,999		72,385		59,882
Dilutive effect of equity awards and warrants																	33		5		6
Weighted average diluted common shares outstanding																	72,032		72,390		59,888
Diluted earnings per common share	$ 0.64	[1]	$ 0.70	[1]	$ 0.71	[1]	$ 0.63	[1]	$ 0.61	[1]	$ 0.63	[1]	$ 0.57	[1]	$ 0.55	[1]	$ 2.68	[1]	$ 2.36	[1]	$ 1.86
Potentially dilutive share options that were not included in the computation of diluted EPS because to do so would be anti-dilutive.																	8		4		13
[1]	Due to averaging of shares, quarterly EPS may not add up to the totals reported for the full year.

Share-Based Payments (Share Awa

Share-Based Payments (Share Awards) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Payment Arrangement [Abstract]
Share-based Payment Arrangement, Expense	$ 9.3	$ 8.4	$ 7.7
Share-based compensation, number authorized (in shares)	3,050,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number	889,017	814,140	805,706	818,755
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value	$ 36.96	$ 36.43	$ 32.23	$ 27.19
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period	405,516	306,592	337,384
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value	$ 35.08	$ 41.47	$ 38.51
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period	(268,253)	(237,146)	(253,509)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value	$ 32.50	$ 28.78	$ 25.67
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period	(62,386)	(61,012)	(96,924)
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period, Weighted Average Grant Date Fair Value	$ 37.12	$ 35.92	$ 28.97
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 23.1
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	2 years 8 months 12 days
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Total Fair Value	$ 8.7	$ 6.7	$ 6.5

Share-Based Payments (Share Opt

Share-Based Payments (Share Options) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based Payment Arrangement, Expense	$ 9,300	$ 8,400	$ 7,700
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Balance at beginning of year (in shares)	5,514
Granted (in shares)	0	0	0
Expired (in shares)	(1,187)
Exercised (in shares)	(4,327)
Balance at end of year (in shares)	0	5,514
Weighted Average Exercise Price at beginning of year	$ 9.91
Weighted Average Exercise Price, Expired	9.91
Weighted Average Exercise Price, Exercised	$ 9.91
Weighted Average Exercise Price at end of year		$ 9.91
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value	$ 108	$ 29	$ 67
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range [Abstract]
Stock-based compensation expense	$ 9,271	$ 8,354	$ 7,745
Share-based Compensation Arrangement by Share-based Payment Award, Options, Vested, Number of Shares	0	0	0
Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Exercisable Period	5 years
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Share Based Compensation Arrangement By Share Based Payment Award, Maximum Term	10 years

Income Tax (Details)

Income Tax (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Tax Contingency [Line Items]
Current Federal Tax Expense (Benefit)									$ 40,471	$ 33,400	$ 39,708
Federal operating loss carryforwards, set to begin to expire in 2024	$ 15,800								15,800
Idaho state operating loss carryforwards, set to begin to expire in 2024	14,300								14,300
Interest and penalties on unrecognized tax benefits									0	0
State operating loss carryforwards, set to begin to expire in 2024	121								121
Unrecognized tax position	0				$ 0				0	0
Current State and Local Tax Expense (Benefit)									6,359	5,446	3,016
Current tax (benefit) expense									46,830	38,846	42,724
Deferred Federal Income Tax Expense (Benefit)									60	(291)	21,524
Deferred State and Local Income Tax Expense (Benefit)									270	399	907
Deferred tax expense (benefit)									330	108	22,431
Income tax provision	11,903	$ 12,378	$ 12,094	$ 10,785	10,734	$ 11,406	$ 9,999	$ 6,815	47,160	38,954	65,155
Deferred tax assets:
Allowance for loan and lease losses	20,489				20,578				20,489	20,578
Deferred Tax Assets, Leasing Arrangements	14,776				0				14,776	0
Supplemental executive retirement plan	11,079				9,501				11,079	9,501
Stock option and restricted stock	2,016				1,850				2,016	1,850
OREO	0				288				0	288
Nonaccrual interest	112				446				112	446
Deferred Tax Assets, Unrealized Losses on Available-for-Sale Securities, Gross	0				10,129				0	10,129
Deferred Tax Assets, Operating Loss Carryforwards	4,136				5,356				4,136	5,356
Other	(245)				(733)				(245)	(733)
Total deferred tax assets	52,853				48,881				52,853	48,881
Deferred tax liabilities:
Asset purchase tax basis difference	(7,888)				(7,229)				(7,888)	(7,229)
Deferred Tax Liabilities, Leasing Arrangements	(13,415)				0				(13,415)	0
FHLB stock dividends	(789)				(790)				(789)	(790)
Deferred loan fees	(4,097)				(4,399)				(4,097)	(4,399)
deferred tax liabilities, unrealized gains on available-for-sale securities	10,091				0				10,091	0
Deferred tax liabilities, purchase accounting	(8,946)				(9,245)				(8,946)	(9,245)
Depreciation	(3,152)				(2,609)				(3,152)	(2,609)
Deferred Tax Liabilities, Derivatives	(3,452)				0				(3,452)	0
Deferred Tax Liabilities, Other	(100)				(195)				(100)	(195)
Total deferred tax liabilities	51,930				24,467				51,930	24,467
Net deferred tax (liability) asset	923				24,414				923	24,414
Reconciliation of effective income tax rate with federal statutory tax rate
Income tax based on statutory rate									$ 50,738	$ 44,485	$ 62,262
Income tax based on statutory rate, percent									21.00%	21.00%	35.00%
Federal income tax rate 2018									21.00%
Tax exempt instrument									$ (6,771)	$ (6,423)	$ (8,485)
Tax exempt instrument, percent									(3.00%)	(3.00%)	(5.00%)
Life insurance proceeds									$ (1,963)	$ (1,261)	$ (3,351)
Life insurance proceeds, percent									(1.00%)	(1.00%)	(2.00%)
effective income tax rate reconciliation, nondeductible expense, business combination, amount									$ 0	$ 0	$ 825
effective income tax rate reconciliation, nondeductible expense, business combination, percent									0.00%	0.00%	1.00%
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount									$ 0	$ 0	$ 12,210
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Percent									0.00%	0.00%	7.00%
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount									$ 5,134	$ 4,931	$ 2,550
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Percent									2.00%	2.00%	1.00%
Other, net									$ 22	$ (2,778)	$ (856)
Other, net, percent									1.00%	(1.00%)	0.00%
Income tax provision	$ 11,903	$ 12,378	$ 12,094	$ 10,785	$ 10,734	$ 11,406	$ 9,999	$ 6,815	$ 47,160	$ 38,954	$ 65,155
Income tax provision (benefit), percent									20.00%	18.00%	37.00%

Regulatory Capital Requiremen_3

Regulatory Capital Requirements (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital Conservation Buffer	5.60%
Common Equity Tier One Capital	$ 1,317,202	$ 1,253,394
Common Equity Tier 1 Capital to Risk Weighted Assets	12.45%	12.74%
Common Equity Tier One Capital Required for Capital Adequacy	$ 476,260	$ 442,717
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Capital Required for Capital Adequacy plus capital conservation buffer phase-in		$ 627,182
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in		6.38%
Common Equity Tier One Capital Required for Capital Adequacy - minimum required plus fully phased in capital conservation buffer	$ 740,849	$ 688,670
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	7.00%	7.00%
Total Capital, Actual Amount	$ 1,439,877	$ 1,376,555
Total Capital (to risk-weighted assets), Ratio	13.60%	13.99%
Total Capital For Capital Adequacy Purposes, Amount	$ 846,685	$ 787,052
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Capital Required for Capital Adequacy plus capital conservation buffer phase-in		$ 971,517
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in		9.88%
Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 1,111,274	$ 1,033,006
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	10.50%	10.50%
Tier 1 Capital, Actual Amount	$ 1,317,202	$ 1,253,394
Tier 1 Capital (to risk-weighted assets), Ratio	12.45%	12.74%
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 635,014	$ 590,289
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio	6.00%	6.00%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer phase-in		$ 774,754
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in		7.88%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 899,603	$ 836,243
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	8.50%	8.50%
Tier 1 Capital, Actual Amount	$ 1,317,202	$ 1,253,394
Tier 1 Capital (to average assets), Ratio	10.17%	10.24%
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 517,938	$ 489,399
Tier 1 Capital (to average assets) For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Banking Subsidiaries [Member]
Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]
Capital Conservation Buffer	5.29%
Common Equity Tier One Capital	$ 1,318,044	$ 1,274,317
Common Equity Tier 1 Capital to Risk Weighted Assets	12.46%	12.96%
Common Equity Tier One Capital Required for Capital Adequacy	$ 475,913	$ 442,552
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets	4.50%	4.50%
Common Equity Tier One Capital Required for Capital Adequacy plus capital conservation buffer phase-in		$ 626,948
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in		6.38%
Common Equity Tier One Capital Required for Capital Adequacy - minimum required plus fully phased in capital conservation buffer	$ 740,310	$ 688,414
Common Equity Tier 1 Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	7.00%	7.00%
Common Equity Tier One Risk Based Capital Required to be Well Capitalized	$ 687,430	$ 639,241
Common Equity Tier 1 Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	6.50%
Total Capital, Actual Amount	$ 1,405,422	$ 1,362,016
Total Capital (to risk-weighted assets), Ratio	13.29%	13.85%
Total Capital For Capital Adequacy Purposes, Amount	$ 846,068	$ 786,759
Total Capital (to risk-weighted assets), For Capital Adequacy Purposes, Ratio	8.00%	8.00%
Capital Required for Capital Adequacy plus capital conservation buffer phase-in		$ 971,155
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in		9.88%
Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 1,110,464	$ 1,032,621
Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	10.50%	10.50%
Total Capital To Be Well Capitalized Under Prompt Corrective Action Provision, Amount	$ 1,057,585	$ 983,448
Total Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision	10.00%	10.00%
Tier 1 Capital, Actual Amount	$ 1,318,044	$ 1,274,317
Tier 1 Capital (to risk-weighted assets), Ratio	12.46%	12.96%
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 634,551	$ 590,069
Tier 1 Capital (to risk-weighted assets) For Capital Adequacy Purposes, Ratio	6.00%	6.00%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer phase-in		$ 774,465
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer phase-in		7.88%
Tier One Risk Based Capital Required for Capital Adequacy plus capital conservation buffer fully phased-in	$ 898,947	$ 835,931
Tier One Based Capital Required for Capital Adequacy to Risk Weighted Assets plus capital conservation buffer fully phased-in	8.50%	8.50%
Tier 1 Capital To Be Well Capitalized Under Prompt Corrective Action Provision, Amount	$ 846,068	$ 786,759
Tier 1 Capital (to risk-weighted assets) To Be Well Capitalized Under Prompt Corrective Action Provision, Ratio	8.00%	8.00%
Tier 1 Capital, Actual Amount	$ 1,318,044	$ 1,274,317
Tier 1 Capital (to average assets), Ratio	10.22%	10.42%
Tier 1 Capital For Capital Adequacy Purposes, Amount	$ 515,797	$ 489,254
Tier 1 Capital (to average assets) For Capital Adequacy Purposes, Ratio	4.00%	4.00%
Tier 1 Capital To Be Well Capitalized Under Prompt Corrective Provision, Amount	$ 644,746	$ 611,567
Tier 1 Capital (to average assets) To Be Well Capitalized Under Prompt Corrective Provision, Ratio	5.00%	5.00%

Parent Company Financial Info_3

Parent Company Financial Information (Condensed Balance Sheets) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Assets
Cash and due from banks	$ 223,541	$ 260,180
Interest-earning deposits	24,132	17,407
Total cash and cash equivalents	247,673	277,587	$ 342,533	$ 224,238
Goodwill	765,842	765,842	765,842	382,762
Other assets	346,275	280,250
Total Assets	14,079,524	13,095,145
Liabilities and Shareholders’ Equity
Subordinated Debt	35,277	35,462
Other liabilities	181,671	107,291
Total liabilities	11,919,562	11,061,496
Shareholders’ equity	2,159,962	2,033,649	1,949,922	1,251,012
Total liabilities and shareholders' equity	14,079,524	13,095,145
Parent Company [Member]
Assets
Cash and due from banks	6,088	945
Interest-earning deposits	21,717	7,226
Total cash and cash equivalents	27,805	8,171	$ 9,298	$ 2,447
Goodwill	4,729	4,729
Other assets	1,675	1,595
Total Assets	2,195,919	2,069,662
Liabilities and Shareholders’ Equity
Subordinated Debt	35,277	35,462
Other liabilities	680	551
Total liabilities	35,957	36,013
Shareholders’ equity	2,159,962	2,033,649
Total liabilities and shareholders' equity	2,195,919	2,069,662
Banking Subsidiaries [Member] | Parent Company [Member]
Assets
Investment in subsidiaries	2,156,039	2,049,855
Other Subsidiaries [Member] | Parent Company [Member]
Assets
Investment in subsidiaries	$ 5,671	$ 5,312

Parent Company Financial Info_4

Parent Company Financial Information (Condensed Statements of Income) (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
		Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income
Deposits in banks										$ 1,312	$ 702	$ 813
Expense
Compensation and employee benefits										212,867	200,199	169,674
Subordinated debentures										1,871	1,871	304
Other borrowings										669	504	575
Other expense	[1]									34,152	37,024	34,608
Income before income tax benefit and equity in undistributed (excess distributed) earnings of subsidiaries		$ 58,032	$ 63,105	$ 63,818	$ 56,656	$ 55,482	$ 57,821	$ 51,748	$ 46,785	241,611	211,836	177,983
Provision for income taxes		11,903	12,378	12,094	10,785	10,734	11,406	9,999	6,815	47,160	38,954	65,155
Net income		$ 46,129	$ 50,727	$ 51,724	$ 45,871	$ 44,748	$ 46,415	$ 41,749	$ 39,970	194,451	172,882	112,828
Parent Company [Member]
Income
Dividend from banking subsidiaries										168,000	85,250	66,800
Deposits in banks										100	12	2
Other income										68	56	8
Total Income										168,168	85,318	66,810
Expense
Compensation and employee benefits										791	978	732
Subordinated debentures										1,871	1,871	304
Other borrowings										0	4	60
Other expense										2,111	2,058	3,090
Total Expenses										4,773	4,911	4,186
Income before income tax benefit and equity in undistributed (excess distributed) earnings of subsidiaries										163,395	80,407	62,624
Provision for income taxes										(967)	(1,017)	(548)
Income before equity in undistributed earnings of subsidiaries										164,362	81,424	63,172
Equity in undistributed earnings of subsidiaries										30,089	91,458	49,656
Net income										$ 194,451	$ 172,882	$ 112,828
[1]	Beginning January 1, 2019, B&O taxes are reported separately from other taxes, licenses and fees, which are now reported under “other noninterest expense.” Prior periods have been reclassified to conform to current period presentation.

Parent Company Financial Info_5

Parent Company Financial Information (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Condensed Financial Statements, Captions [Line Items]
Stock Issued									$ 0	$ 0	$ 636,385
Operating Activities
Net income	$ 46,129	$ 50,727	$ 51,724	$ 45,871	$ 44,748	$ 46,415	$ 41,749	$ 39,970	194,451	172,882	112,828
Adjustments to reconcile net income to net cash provided by operating activities:
Stock-based compensation expense									9,271	8,354	7,745
Net cash provided by operating activities									204,747	237,201	128,525
Investing Activities
Net cash paid in business combinations									0	0	80,472
Net cash provided by investing activities									(865,450)	(506,083)	(199,489)
Financing Activities
Cash dividends paid									(101,911)	(83,440)	(51,308)
Repayments of Junior Subordinated Debt									0	8,248	6,186
Payments for cash settlement of acquired equity awards									0	0	(7,345)
Purchase and retirement of common stock									2,792	2,677	2,299
Purchase of treasury stock									(50,834)	0	0
Proceeds from exercise of stock options									2,025	1,857	1,980
Net cash provided by financing activities									630,789	203,936	189,259
Increase (decrease) in cash and cash equivalents									(29,914)	(64,946)	118,295
Cash and cash equivalents at beginning of period				277,587				342,533	277,587	342,533	224,238
Cash and cash equivalents at end of period	247,673				277,587				247,673	277,587	342,533
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Stock Issued									0	0	636,385
Operating Activities
Net income									194,451	172,882	112,828
Adjustments to reconcile net income to net cash provided by operating activities:
Equity in undistributed earnings of subsidiaries									(30,089)	(91,458)	(49,656)
Stock-based compensation expense									9,271	8,354	7,745
Net changes in other assets and liabilities									(133)	1,622	1,672
Net cash provided by operating activities									173,500	91,400	72,589
Investing Activities
Net cash paid in business combinations									0	0	(580)
Net cash provided by investing activities									0	0	(580)
Financing Activities
Cash dividends paid									(102,265)	(83,459)	(51,308)
Repayments of Junior Subordinated Debt									0	8,248	6,186
Payments for cash settlement of acquired equity awards									0	0	7,345
Purchase and retirement of common stock									2,792	2,677	2,299
Purchase of treasury stock									(50,834)	0	0
Proceeds from exercise of stock options									2,025	1,857	1,980
Net cash provided by financing activities									(153,866)	(92,527)	(65,158)
Increase (decrease) in cash and cash equivalents									19,634	(1,127)	6,851
Cash and cash equivalents at beginning of period				$ 8,171				$ 9,298	8,171	9,298	2,447
Cash and cash equivalents at end of period	$ 27,805				$ 8,171				$ 27,805	$ 8,171	$ 9,298

Summary Of Quarterly Financia_3

Summary Of Quarterly Financial Information (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2019		Sep. 30, 2019		Jun. 30, 2019		Mar. 31, 2019		Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2019		Dec. 31, 2018		Dec. 31, 2017
Quarterly Financial Information Disclosure [Abstract]
Total interest income	$ 133,109		$ 132,533		$ 135,422		$ 128,888		$ 129,801		$ 127,575		$ 120,549		$ 119,144		$ 529,952		$ 497,069		$ 374,746
Total interest expense	8,292		10,083		10,306		7,866		5,913		4,779		3,875		3,663		36,547		18,230		6,757
Net Interest Income	124,817		122,450		125,116		121,022		123,888		122,796		116,674		115,481		493,405		478,839		367,989
Provision for loan and lease losses	1,614		299		218		1,362		1,789		3,153		3,975		5,852		3,493		14,769		8,631
Noninterest income	21,807		28,030		25,648		21,696		20,402		21,019		23,692		23,143		97,181		88,256		109,642
Noninterest expense	86,978		87,076		86,728		84,700		87,019		82,841		84,643		85,987		345,482		340,490		291,017
Income before income taxes	58,032		63,105		63,818		56,656		55,482		57,821		51,748		46,785		241,611		211,836		177,983
Provision for income taxes	11,903		12,378		12,094		10,785		10,734		11,406		9,999		6,815		47,160		38,954		65,155
Net income	$ 46,129		$ 50,727		$ 51,724		$ 45,871		$ 44,748		$ 46,415		$ 41,749		$ 39,970		$ 194,451		$ 172,882		$ 112,828
Per Common Share
Earnings (basic)	$ 0.64	[1]	$ 0.70	[1]	$ 0.71	[1]	$ 0.63	[1]	$ 0.61	[1]	$ 0.63	[1]	$ 0.57	[1]	$ 0.55	[1]	$ 2.68	[1]	$ 2.36	[1]	$ 1.86
Earnings (diluted)	$ 0.64	[1]	$ 0.70	[1]	$ 0.71	[1]	$ 0.63	[1]	$ 0.61	[1]	$ 0.63	[1]	$ 0.57	[1]	$ 0.55	[1]	$ 2.68	[1]	$ 2.36	[1]	$ 1.86
[1]	Due to averaging of shares, quarterly EPS may not add up to the totals reported for the full year.

Revenue from Contracts with C_3

Revenue from Contracts with Customers (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Disaggregation of Revenue [Line Items]
Deposit account and treasury management fees									$ 35,695	$ 36,072	$ 30,381
Card revenue									15,198	19,719	25,627
Financial services and trust revenue									12,799	12,135	11,478
Revenue from contracts with customers									63,692	67,926
Noninterest income, excluding revenue from contracts with customers									33,489	20,330
Noninterest income	$ 21,807	$ 28,030	$ 25,648	$ 21,696	$ 20,402	$ 21,019	$ 23,692	$ 23,143	$ 97,181	$ 88,256	$ 109,642