Fair Value Measurements Fair Value, Assets and Liabilities -Defined Benefit Pension Plans(Details) (USD $) | 12 Months Ended | |
In Thousands, unless otherwise specified | Dec. 31, 2014 | Dec. 31, 2013 | Dec. 31, 2012 |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | $725,770 | $681,620 | $643,725 |
Change in fair value of plan assets [Roll Forward] | | | |
Beginning of measurement period | | | 643,725 |
End of measurement period | 725,770 | 681,620 | 643,725 |
U.S. pension plans | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 421,385 | 408,244 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 421,385 | 408,244 | |
U.S. pension plans | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 19,472 | 24,707 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 19,472 | 24,707 | |
U.S. pension plans | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 401,913 | 383,537 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 401,913 | 383,537 | |
U.S. pension plans | Cash and Cash Equivalents | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 228 | 3,833 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 228 | 3,833 | |
U.S. pension plans | Cash and Cash Equivalents | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 228 | 3,833 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 228 | 3,833 | |
U.S. pension plans | Short-term Investment Funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 6,168 | 5,072 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 6,168 | 5,072 | |
U.S. pension plans | Short-term Investment Funds | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 6,168 | 5,072 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 6,168 | 5,072 | |
U.S. pension plans | U.S. | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 104,073 | 83,649 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 104,073 | 83,649 | |
U.S. pension plans | U.S. | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 104,073 | 83,649 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 104,073 | 83,649 | |
U.S. pension plans | International | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 36,604 | 38,090 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 36,604 | 38,090 | |
U.S. pension plans | International | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 36,604 | 38,090 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 36,604 | 38,090 | |
U.S. pension plans | U.S. fixed income funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 256,196 | 262,966 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 256,196 | 262,966 | |
U.S. pension plans | U.S. fixed income funds | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 19,244 | 20,874 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 19,244 | 20,874 | |
U.S. pension plans | U.S. fixed income funds | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 236,952 | 242,092 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 236,952 | 242,092 | |
U.S. pension plans | International fixed income funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 17,378 | 13,191 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 17,378 | 13,191 | |
U.S. pension plans | International fixed income funds | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 0 | 0 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 0 | 0 | |
U.S. pension plans | International fixed income funds | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 17,378 | 13,191 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 17,378 | 13,191 | |
U.S. pension plans | Other | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 738 | 1,443 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 738 | 1,443 | |
U.S. pension plans | Other | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 738 | 1,443 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 738 | 1,443 | |
U.K. pension plans | U.K. | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 268,425 | 246,678 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 268,425 | 246,678 | |
U.K. pension plans | U.K. | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 1,968 | 13,229 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 1,968 | 13,229 | |
U.K. pension plans | U.K. | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 251,717 | 220,130 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 251,717 | 220,130 | |
U.K. pension plans | U.K. | Level 3 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 14,740 | 13,319 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 14,740 | 13,319 | |
U.K. pension plans | U.K. | Cash and Cash Equivalents | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 1,968 | 4,322 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 1,968 | 4,322 | |
U.K. pension plans | U.K. | Cash and Cash Equivalents | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 1,968 | 4,322 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 1,968 | 4,322 | |
U.K. pension plans | U.K. | U.S. | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 29,051 | 29,457 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 29,051 | 29,457 | |
U.K. pension plans | U.K. | U.S. | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 29,051 | 29,457 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 29,051 | 29,457 | |
U.K. pension plans | U.K. | International | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 35,506 | 34,579 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 35,506 | 34,579 | |
U.K. pension plans | U.K. | International | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 35,506 | 34,579 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 35,506 | 34,579 | |
U.K. pension plans | U.K. | Money market funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 103,754 | 60,644 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 103,754 | 60,644 | |
U.K. pension plans | U.K. | Money market funds | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 103,754 | 60,644 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 103,754 | 60,644 | |
U.K. pension plans | U.K. | Government securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 42,672 | 58,958 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 42,672 | 58,958 | |
U.K. pension plans | U.K. | Government securities | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | | 8,778 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | | 8,778 | |
U.K. pension plans | U.K. | Government securities | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 42,672 | 50,180 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 42,672 | 50,180 | |
U.K. pension plans | U.K. | Corporate bonds and debt securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 11,669 | 15,958 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 11,669 | 15,958 | |
U.K. pension plans | U.K. | Corporate bonds and debt securities | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 11,669 | 15,958 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 11,669 | 15,958 | |
U.K. pension plans | U.K. | Mortgage-backed securities | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 782 | 789 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 782 | 789 | |
U.K. pension plans | U.K. | Mortgage-backed securities | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 782 | 789 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 782 | 789 | |
U.K. pension plans | U.K. | Alternative strategy funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 28,283 | 28,652 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 28,283 | 28,652 | |
U.K. pension plans | U.K. | Alternative strategy funds | Level 1 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | | 129 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | | 129 | |
U.K. pension plans | U.K. | Alternative strategy funds | Level 2 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 28,283 | 28,523 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 28,283 | 28,523 | |
U.K. pension plans | U.K. | Real estate funds | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 14,740 | 13,319 | |
Change in fair value of plan assets [Roll Forward] | | | |
End of measurement period | 14,740 | 13,319 | |
U.K. pension plans | U.K. | Real estate funds | Level 3 | | | |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] | | | |
Fair value of plan assets | 14,740 | 13,319 | |
Change in fair value of plan assets [Roll Forward] | | | |
Beginning of measurement period | 13,319 | 13,238 | |
Related to assets still held at the reporting date | 1,412 | 55 | |
Purchases, sales and settlements-net | 9 | 26 | |
End of measurement period | $14,740 | $13,319 | |