XML 36 R22.htm IDEA: XBRL DOCUMENT
v3.19.1

Accumulated Other Comprehensive Income | 3 Months Ended
--- | ---
Mar. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Abstract] |
Accumulated Other Comprehensive Income | Accumulated Other Comprehensive Income The following table shows changes in accumulated other comprehensive income (loss) by component for the three month periods ended March 31, 2019 and 2018:
|  | 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)
Three months ended March 31, 2019 |  | (in thousands)
Beginning balance |  | $ | (33,128 | ) |  | $ | (2,177 | ) |  | $ | — |  |  | $ | (35,305 | )
Other comprehensive income before reclassifications |  | 32,063 |  |  | — |  |  | 4,810 |  |  | 36,873 |
Amounts reclassified from accumulated other comprehensive loss (2) |  | 1,417 |  |  | 61 |  |  | — |  |  | 1,478 |
Net current-period other comprehensive income |  | 33,480 |  |  | 61 |  |  | 4,810 |  |  | 38,351 |
Ending balance |  | $ | 352 |  |  | $ | (2,116 | ) |  | $ | 4,810 |  |  | $ | 3,046 |
Three months ended March 31, 2018 |  |  |  |  |  |  |  |
Beginning balance |  | $ | (19,779 | ) |  | $ | (2,446 | ) |  | $ | — |  |  | $ | (22,225 | )
Adjustment pursuant to adoption of ASU 2016-01 |  | 157 |  |  | — |  |  | — |  |  | 157 |
Other comprehensive loss before reclassifications |  | (26,048 | ) |  | — |  |  | — |  |  | (26,048 | )
Amounts reclassified from accumulated other comprehensive loss (2) |  | (78 | ) |  | 61 |  |  | — |  |  | (17 | )
Net current-period other comprehensive income (loss) |  | (26,126 | ) |  | 61 |  |  | — |  |  | (26,065 | )
Ending balance |  | $ | (45,748 | ) |  | $ | (2,385 | ) |  | $ | — |  |  | $ | (48,133 | )
__________ (1) All amounts are net of tax. Amounts in parenthesis indicate debits. (2) See following table for details about these reclassifications. The following table shows details regarding the reclassifications from accumulated other comprehensive income (loss) for the three month periods ended March 31, 2019 and 2018:
|  | Amount Reclassified from Accumulated Other Comprehensive Income (Loss) |  |
|  | Three Months Ended March 31, |  | Affected line Item in the Consolidated
|  | 2019 |  | 2018 |  | Statement of Income
|  | (in thousands) |
Unrealized gains and losses on available for sale debt securities |  |  |  |  |  |
Investment securities (gains) losses, net |  | $ | (1,847 | ) |  | $ | 102 |  |  | Investment securities gains, net
|  | (1,847 | ) |  | 102 |  |  | Total before tax
|  | 430 |  |  | (24 | ) |  | Income tax provision
|  | $ | (1,417 | ) |  | $ | 78 |  |  | Net of tax
Amortization of pension plan liability |  |  |  |  |  |
Actuarial losses |  | $ | (80 | ) |  | $ | (80 | ) |  | Compensation and employee benefits
|  | (80 | ) |  | (80 | ) |  | Total before tax
|  | 19 |  |  | 19 |  |  | Income tax provision
|  | $ | (61 | ) |  | $ | (61 | ) |  | Net of tax

X
- Definition Accumulated Other Comprehensive Income (Loss) [Abstract] + References No definition available. + Details
Name: | colb_AccumulatedOtherComprehensiveIncomeLossAbstract
Namespace Prefix: | colb_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Accumulated Other Comprehensive Income (Loss) + References No definition available. + Details
Name: | colb_AccumulatedOtherComprehensiveIncomeLossTextBlock
Namespace Prefix: | colb_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration