This element represents the portion of the balance sheet assertion valued at fair value by the entity whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. This item includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the Company may deposit additional funds at any time and also effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months.

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Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.

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- Definition

Description of target allocation percentages, or range of percentages, considering the major categories of plan assets as of the latest statement of financial position presented (on a weighted-average basis for employers with more than one plan) that are pertinent to an understanding of the plan investment policies and strategies.

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Retirement Plans (Information About Plan Assets) (United Kingdom) (Details) (USD $) In Thousands, unless otherwise specified						12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 United Kingdom Benefit Plans [Member]	Dec. 31, 2011 United Kingdom Benefit Plans [Member]	Dec. 31, 2010 United Kingdom Benefit Plans [Member]	Dec. 31, 2012 Equity Funds [Member] United Kingdom Benefit Plans [Member]	Dec. 31, 2012 Commercial Property [Member] United Kingdom Benefit Plans [Member]	Dec. 31, 2012 U.K. Government securities [Member] United Kingdom Benefit Plans [Member]	Dec. 31, 2012 Cash and Cash Equivalents [Member] United Kingdom Benefit Plans [Member]	Dec. 31, 2012 Real Estate Investment [Member] United Kingdom Benefit Plans [Member]	Dec. 31, 2011 Real Estate Investment [Member] United Kingdom Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Target Allocation Percentage						Up to 100%	Not to exceed 50%	Not to exceed 50%	Up to 100%
Cash and cash equivalents	$ 84,665	$ 64,793	$ 520	$ 180
Equity securities			2,250	2,286
Bonds			1,529	965
Commercial property										1,636	1,264
Alternatives			116	465
Fair value of plan assets			$ 6,051	$ 5,160	$ 5,293