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Employee Benefit Plans (Narrative) (Details) shares in Millions, $ in Millions | 12 Months Ended
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Dec. 31, 2015 USD ($) N shares | Dec. 31, 2014 USD ($) | Dec. 31, 2013 USD ($)
Defined Benefit Plan Disclosure [Line Items] |  |  |
Accumulated benefit obligation | $ 62.3 | $ 61.9 |
Increase (decrease) in annual rate per capita cost of covered healthcare benefits, next year | 9.00% |  |
Increase (decrease) in annual rate per capita cost of covered healthcare benefits, 2017-2019 | 1.00% |  |
Increase (decrease) in annual rate per capita cost of covered healthcare benefits, 2020-2021 | 0.50% |  |
Annual rate of increase in the per capita cost of covered healthcare benefits | 5.00% |  |
Description of 401(k) | The Company has a 401(k) defined contribution plan, which covers substantially all employees with more than 1,000 hours of service. Under the terms of the Plan, the Company matches 100% of a participant’s contributions, which do not exceed 1% of a participant’s compensation, plus 50% of a participant’s contributions exceeding 1%, but not more than 6%. The Company’s matching contributions were $0.6 million, $0.6 million and $0.5 million for the years ended December 31, 2015, 2014 and 2013, respectively. For those employees hired after March 31, 2007 and still actively employed on December 31, 2015, the Company approved and will fund discretionary contribution of $0.4 million, which was based on 5.0% of eligible 2014 compensation. For the years ended December 31, 2013 and 2012, the Company made discretionary contributions of $0.3 million and $0.3 million, respectively, for those qualifying employees. |  |
Number of hours required to participate in contribution plan | N | 1,000 |  |
Percent of participants contributions matched by company, below one percent of participants compensation | 100.00% |  |
Percent of participants contributions matched by company, above one percent of participants compensation | 50.00% |  |
Threshold percentage of participants compensation at which matching decreases | 1.00% |  |
Matching contributions, percent | 6.00% |  |
Matching contributions | $ 0.6 | 0.5 | $ 0.5
Discretionary contributions, percent | 5.00% |  |
Discretionary contributions | $ 0.4 | 0.3 | 0.3
Escrow account maintained for 2008 restricted stock plan | shares | 0.1 |  |
Maximum number of shares authorized for grant | shares | 0.3 |  |
Number of shares authorized for grant, unissued | shares | 0.1 |  |
Fair value of vested restricted shares | $ 0.3 | $ 0.5 | $ 0.5
Pension Benefit Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Allocation of plan assets | 100.00% | 100.00% |
Benfit plan, Cash contributions | $ 3.3 |  |
Expected cash contributions next fiscal year | $ 3.3 |  |
Other Benefits Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Allocation of plan assets | 100.00% | 100.00% |
Benfit plan, Cash contributions | $ 1.7 |  |
Expected cash contributions next fiscal year | $ 1.5 |  |
Equity Securities [Member] | Pension Benefit Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Allocation of plan assets | 59.10% | 60.70% |
Equity Securities [Member] | Other Benefits Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Allocation of plan assets | 50.00% | 49.50% |
Equity Securities [Member] | Middlesex [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Allocation of plan assets | 2.00% | 1.80% |
Common stock in plan, value | $ 1.0 | $ 0.9 |

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- Definition The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Health Care Cost Trend Rate -URI http://asc.fasb.org/extlink&oid=6514820 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (l) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
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- Definition If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=58242635&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e2417-114920 + Details
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- Definition Description of the terms and benefits provided by the employer's defined contribution plans. A defined contribution plan provides benefits in return for services rendered, provides an individual account for each participant, and has terms that specify how contributions to the individual's account are to be determined rather than the amount of benefits the individual is to receive. Under a defined contribution pension plan, the benefits a participant will receive depend solely on the amount contributed to the participant's account, the returns earned on investments of those contributions, and forfeitures of other participants' benefits that may be allocated to such participant's account. A description of the plan(s) including employee groups covered, the basis for determining contributions, and the nature and effects of significant matters affecting comparability of information for all periods presented. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 70 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=49170846&loc=d3e28014-114942 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Defined Contribution Plan -URI http://asc.fasb.org/extlink&oid=49180617 + Details
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- Definition The maximum number of shares (or other type of equity) originally approved (usually by shareholders and board of directors), net of any subsequent amendments and adjustments, for awards under the equity-based compensation plan. As stock or unit options and equity instruments other than options are awarded to participants, the shares or units remain authorized and become reserved for issuance under outstanding awards (not necessarily vested). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a)(3) -URI http://asc.fasb.org/extlink&oid=6415400&loc=d3e5070-113901 + Details
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