Investments at Fair Value for Company Sponsored Pension Benefit Plans Within Fair Value Hierarchy (Details) (USD $) | Dec. 31, 2013 | Dec. 31, 2012 |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | $286,598,000 | $254,556,000 |
Cash and cash equivalents | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 4,314,000 | 3,786,000 |
Common and collective trusts | International small cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 15,845,000 | 12,725,000 |
Common and collective trusts | Global/International equity | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 21,198,000 | 16,656,000 |
Common and collective trusts | Domestic equity – small/mid cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 17,339,000 |
Common and collective trusts | International equity emerging markets | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 17,809,000 | 17,672,000 |
Common stock | Industrials | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 9,307,000 | 9,475,000 |
Common stock | Energy | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 2,663,000 | 1,966,000 |
Common stock | Consumer | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 8,002,000 | 8,270,000 |
Common stock | Healthcare | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 6,013,000 | 7,386,000 |
Common stock | Finance | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 11,566,000 | 13,000,000 |
Common stock | Utilities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 1,711,000 | 2,305,000 |
Common stock | Information technology | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 8,785,000 | 6,828,000 |
Common stock | Foreign | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 6,175,000 | 6,078,000 |
Mutual funds | Foreign large blend | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 18,492,000 | 18,907,000 |
Mutual funds | Long-term bond fund | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 137,031,000 | 114,557,000 |
Mutual funds | Mid-cap Growth Fund [Member] | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 18,009,000 | ' |
Corporate debt securities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 1,073,000 |
Investments | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 286,920,000 | 258,023,000 |
Payable held under securities lending agreement | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | -322,000 | -3,467,000 |
Fair Value, Inputs, Level 1 | Cash and cash equivalents | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 4,314,000 | 3,786,000 |
Fair Value, Inputs, Level 1 | Common and collective trusts | International small cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 1 | Common and collective trusts | Global/International equity | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 1 | Common and collective trusts | Domestic equity – small/mid cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 0 |
Fair Value, Inputs, Level 1 | Common and collective trusts | International equity emerging markets | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 1 | Common stock | Industrials | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 9,307,000 | 9,475,000 |
Fair Value, Inputs, Level 1 | Common stock | Energy | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 2,663,000 | 1,966,000 |
Fair Value, Inputs, Level 1 | Common stock | Consumer | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 8,002,000 | 8,270,000 |
Fair Value, Inputs, Level 1 | Common stock | Healthcare | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 6,013,000 | 7,386,000 |
Fair Value, Inputs, Level 1 | Common stock | Finance | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 11,566,000 | 13,000,000 |
Fair Value, Inputs, Level 1 | Common stock | Utilities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 1,711,000 | 2,305,000 |
Fair Value, Inputs, Level 1 | Common stock | Information technology | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 8,785,000 | 6,828,000 |
Fair Value, Inputs, Level 1 | Common stock | Foreign | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 6,175,000 | 6,078,000 |
Fair Value, Inputs, Level 1 | Mutual funds | Foreign large blend | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 18,492,000 | 18,907,000 |
Fair Value, Inputs, Level 1 | Mutual funds | Long-term bond fund | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 137,031,000 | 114,557,000 |
Fair Value, Inputs, Level 1 | Mutual funds | Mid-cap Growth Fund [Member] | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 18,009,000 | ' |
Fair Value, Inputs, Level 1 | Corporate debt securities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 0 |
Fair Value, Inputs, Level 1 | Investments | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 232,068,000 | 192,558,000 |
Fair Value, Inputs, Level 2 | Cash and cash equivalents | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common and collective trusts | International small cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 15,845,000 | 12,725,000 |
Fair Value, Inputs, Level 2 | Common and collective trusts | Global/International equity | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 21,198,000 | 16,656,000 |
Fair Value, Inputs, Level 2 | Common and collective trusts | Domestic equity – small/mid cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 17,339,000 |
Fair Value, Inputs, Level 2 | Common and collective trusts | International equity emerging markets | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 17,809,000 | 17,672,000 |
Fair Value, Inputs, Level 2 | Common stock | Industrials | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Energy | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Consumer | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Healthcare | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Finance | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Utilities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Information technology | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Common stock | Foreign | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Mutual funds | Foreign large blend | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Mutual funds | Long-term bond fund | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 2 | Mutual funds | Mid-cap Growth Fund [Member] | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | ' |
Fair Value, Inputs, Level 2 | Corporate debt securities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 1,073,000 |
Fair Value, Inputs, Level 2 | Investments | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 54,852,000 | 65,465,000 |
Fair Value, Inputs, Level 3 | Cash and cash equivalents | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common and collective trusts | International small cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common and collective trusts | Global/International equity | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common and collective trusts | Domestic equity – small/mid cap | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 0 |
Fair Value, Inputs, Level 3 | Common and collective trusts | International equity emerging markets | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Industrials | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Energy | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Consumer | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Healthcare | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Finance | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Utilities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Information technology | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Common stock | Foreign | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Mutual funds | Foreign large blend | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Mutual funds | Long-term bond fund | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | 0 |
Fair Value, Inputs, Level 3 | Mutual funds | Mid-cap Growth Fund [Member] | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | 0 | ' |
Fair Value, Inputs, Level 3 | Corporate debt securities | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | ' | 0 |
Fair Value, Inputs, Level 3 | Investments | ' | ' |
Defined Benefit Plan Disclosure [Line Items] | ' | ' |
Fair value of plan assets | $0 | $0 |