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Components of Net Periodic Benefit Cost (Details) (USD $) | 1 Months Ended | 3 Months Ended | 9 Months Ended |  |
--- | --- | --- | --- | --- | ---
Jun. 30, 2013 acre | Nov. 30, 2012 acre | Apr. 30, 2011 acre | Sep. 30, 2013 acre | Sep. 30, 2012 | Sep. 30, 2013 acre | Sep. 30, 2012 | Oct. 31, 2011 item | Dec. 31, 2009
Net periodic benefit costs for pension benefits |  |  |  |  |  |  |  |  |
Interest cost |  |  |  | $ 720,000 | $ 798,000 | $ 2,160,000 | $ 2,394,000 |  |
Expected return on plan assets |  |  |  | (726,000) | (717,000) | (2,178,000) | (2,151,000) |  |
Recognized actuarial loss |  |  |  | 228,000 | 185,000 | 684,000 | 555,000 |  |
Net expense |  |  |  | 222,000 | 266,000 | 666,000 | 798,000 |  |
Security to support the unfunded liabilities of the Bargaining Plan |  |  |  |  |  |  |  |  | 5,200,000
Area of property pledged as security (in acres) |  | 7,000 | 1,400 |  |  |  |  |  |
Period for release of property pledged as collateral |  | 5 years | 5 years |  |  |  |  |  |
Additional security to support unfunded liabilities |  |  |  |  |  |  |  | 18,700,000 |
Number of pension plans |  |  |  |  |  |  |  | 2 |
Area of parcel proposed to be sold (in acres) | 270 |  |  |  |  |  |  |  |
Unfunded pension fund liabilities |  |  |  | 24,200,000 |  | 24,200,000 |  |  |
Area of property held as collateral for unfunded pension obligations (in acres) |  |  |  | 8,400 |  | 8,400 |  |  |
Carrying value of property held as collateral for unfunded pension obligations |  |  |  | 1,800,000 |  | 1,800,000 |  |  |
Expected minimum required contributions |  |  |  |  |  | 2,100,000 |  |  |
Contributions funded by employer |  |  |  |  |  | $ 1,600,000 |  |  |

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- Definition Represents the area of real estate secured for unfunded pension obligations. + References No definition available. + Details
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- Definition Represents the area of real estate which is proposed to be sold. + References No definition available. + Details
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- Definition Represents the additional security provided to support the unfunded liabilities of the pension plans. + References No definition available. + Details
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- Definition Represents the area of real estate property pledged as security. + References No definition available. + Details
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- Definition Represents the number of pension plans that the entity was required to provide additional security for the unfunded liabilities. + References No definition available. + Details
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- Definition Represents the period for release of real estate property pledged as collateral. + References No definition available. + Details
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- Definition Represents the security provided to support the unfunded liabilities of the pension plan. + References No definition available. + Details
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- Definition Represents the carrying amount, as of the date of the latest financial statement presented, of real estate owned but transferred to serve as collateral for the payment of the unfunded pension obligations. + References No definition available. + Details
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- Definition This represents the noncurrent liability recognized in the balance sheet that is associated with the defined benefit pension plans. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.24) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2417-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e2410-114920 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 5: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=21915240&loc=d3e1703-114919 + Details
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- Definition Amount of gain (loss) related to change in benefit obligation resulting from changes in actuarial assumptions, for example, but not limited to, interest, mortality, employee turnover, salary, and temporary deviation from the substantive plan. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Glossary Gain or Loss -URI http://asc.fasb.org/extlink&oid=6514294 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(4) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Glossary Gain or Loss -URI http://asc.fasb.org/extlink&oid=6749293 + Details
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- Definition The increase in the fair value of plan assets from contributions made by the employer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Definition An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 30 -Glossary Expected Return on Plan Assets -URI http://asc.fasb.org/extlink&oid=6512136 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 60 -Glossary Expected Return on Plan Assets -URI http://asc.fasb.org/extlink&oid=6512171 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(3) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Definition The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h)(2) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (a)(2) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Definition The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain (loss), prior service cost or credit, transition asset or obligation, and gain (loss) due to settlements or curtailments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (h) -URI http://asc.fasb.org/extlink&oid=28361610&loc=d3e1928-114920 + Details
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- Definition Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period. + References No definition available. + Details
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