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Pension Plans and Other Postretirement Benefits - Additional Information (Detail) (USD $)
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12 Months Ended |
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Dec. 31, 2014
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Dec. 31, 2013
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Dec. 31, 2012
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Dec. 31, 2015
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Recognition of prior service credits for transfer of pension plan resulting from an acquisition |
$ 9,529,000 |
$ 10,548,000 |
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| Recognition of net losses for transfer of pension plan resulting from an acquisition |
42,442,000 |
3,545,000 |
51,880,000 |
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| Percentage of change in assumed health care cost trend rate have nominal effect on service and interest costs and projected benefit obligations |
1.00% |
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| Impact to projected benefit obligation |
1,000,000 |
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| Estimated contributions to defined benefit pension plans |
12,200,000 |
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| Contribution made to defined contribution plans |
6,800,000 |
6,300,000 |
7,000,000 |
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| Plan Assets [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Total plan assets, investments in insurance contracts |
92,600,000 |
81,300,000 |
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| Defined Benefit Pension Plans [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Net benefit costs recognized |
22,429,000 |
22,864,000 |
13,543,000 |
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| Defined Benefit Pension Plans [Member] | Scenario Forecast [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Net loss |
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5,700,000 |
| Net prior service cost (credit) |
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(1,700,000) |
| Other Postretirement Benefit Plans [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Years of service |
10 years |
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| Other Postretirement Benefits Plan, description |
In general, the plan applies to employees hired by Dow before January 1, 2008 and transferred to the Company in connection with the Acquisition, and who are at least 50 years old with 10 years of service. The plan allows for spouse coverage as well. If an employee was hired on or before January 1, 1993, the coverage extends past age 65. For employees hired after January 1, 1993 but before January 1, 2008, coverage ends at age 65. |
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| Net benefit costs recognized |
787,000 |
545,000 |
518,000 |
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| Other Postretirement Benefit Plans [Member] | Brazil [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Defined benefit medical plan, description |
The extended medical plan must include the same level of coverage and other conditions offered to active employees, whereas former employees must assume 100% of the premium cost. |
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| Liabilities recorded under defined benefit plan, business acquisition |
2,700,000 |
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| Increase in goodwill |
1,700,000 |
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| Net periodic benefit costs |
1,000,000 |
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| Other Postretirement Benefit Plans [Member] | Netherlands [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Defined benefit curtailment gain |
1,500,000 |
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| Benefits ceased, date |
Jan. 01, 2015 |
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| Other Postretirement Benefit Plans [Member] | Scenario Forecast [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Net prior service cost (credit) |
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100,000 |
| Other Postretirement Benefit Plans [Member] | Minimum [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Insurance coverage age limit |
50 years |
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| Other Postretirement Benefit Plans [Member] | Maximum [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Insurance coverage age limit |
65 years |
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| Successor Plans [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Recognition of prior service credits for transfer of pension plan resulting from an acquisition |
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13,000,000 |
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| Recognition of net losses for transfer of pension plan resulting from an acquisition |
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1,400,000 |
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| Supplemental Employee Retirement Plan [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Net benefit costs recognized |
1,300,000 |
2,300,000 |
2,600,000 |
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| Change in plan assumptions, actuarial loss |
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2,200,000 |
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| Tax impact of Gain (loss) arising from change in plan assumptions |
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1,400,000 |
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| Benefit obligations |
13,200,000 |
12,700,000 |
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| Amounts of net loss included in AOCI |
2,000,000 |
2,900,000 |
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| Amortization from AOCI into net periodic benefit costs |
800,000 |
700,000 |
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| Supplemental Employee Retirement Plan [Member] | Scenario Forecast [Member] |
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| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] |
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| Amortization from AOCI into net periodic benefit costs |
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$ 800,000 |