Pensions (Fair Values Of Pension Plans By Asset Categories European Plans) (Details) (USD $) In Thousands, unless otherwise specified														12 Months Ended				12 Months Ended				12 Months Ended																																																														12 Months Ended
	Dec. 31, 2011 European Plans [Member]	Dec. 31, 2010 European Plans [Member]	Dec. 31, 2009 European Plans [Member]	Dec. 31, 2011 European Plans [Member] Cash Equivalents [Member]	Dec. 31, 2010 European Plans [Member] Cash Equivalents [Member]	Dec. 31, 2011 European Plans [Member] M&G PP Discretionary Fund [Member]		Dec. 31, 2010 European Plans [Member] M&G PP Discretionary Fund [Member]		Dec. 31, 2011 European Plans [Member] Global Equity 60-40 Index [Member]		Dec. 31, 2010 European Plans [Member] Global Equity 60-40 Index [Member]		Dec. 31, 2011 European Plans [Member] Delta Lloyd Fixed Income [Member] years		Dec. 31, 2010 European Plans [Member] Delta Lloyd Fixed Income [Member]		Dec. 31, 2011 European Plans [Member] Corporate Bonds [Member] years		Dec. 31, 2010 European Plans [Member] Corporate Bonds [Member]		Dec. 31, 2011 European Plans [Member] Government Bonds [Member] years		Dec. 31, 2010 European Plans [Member] Government Bonds [Member]		Dec. 31, 2011 European Plans [Member] Real Estate [Member]		Dec. 31, 2010 European Plans [Member] Real Estate [Member]		Dec. 31, 2011 European Plans [Member] Insurance Reserves [Member]		Dec. 31, 2010 European Plans [Member] Insurance Reserves [Member]		Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member]	Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Cash Equivalents [Member]	Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Cash Equivalents [Member]	Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] M&G PP Discretionary Fund [Member]		Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] M&G PP Discretionary Fund [Member]		Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Global Equity 60-40 Index [Member]		Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Global Equity 60-40 Index [Member]		Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Corporate Bonds [Member]		Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Corporate Bonds [Member]		Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Government Bonds [Member]		Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Government Bonds [Member]		Dec. 31, 2011 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Real Estate [Member]		Dec. 31, 2010 European Plans [Member] Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Real Estate [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member]	Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Cash Equivalents [Member]	Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] M&G PP Discretionary Fund [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Global Equity 60-40 Index [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Delta Lloyd Fixed Income [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Corporate Bonds [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Government Bonds [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Real Estate [Member]		Dec. 31, 2010 European Plans [Member] Significant Observable Inputs (Level 2) [Member] Insurance Reserves [Member]		Dec. 31, 2011 European Plans [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2010 European Plans [Member] Significant Unobservable Inputs (Level 3) [Member]	Dec. 31, 2011 European Plans [Member] Significant Unobservable Inputs (Level 3) [Member] Delta Lloyd Fixed Income [Member]		Dec. 31, 2010 European Plans [Member] Significant Unobservable Inputs (Level 3) [Member] Delta Lloyd Fixed Income [Member]		Dec. 31, 2011 European Plans [Member] Significant Unobservable Inputs (Level 3) [Member] Insurance Reserves [Member]		Dec. 31, 2010 European Plans [Member] Significant Unobservable Inputs (Level 3) [Member] Insurance Reserves [Member]		Dec. 31, 2011 UK Equity Index Fund [Member] Global Equity 60-40 Index [Member]	Dec. 31, 2011 Overseas Index Funds [Member] Global Equity 60-40 Index [Member]	Dec. 31, 2011 North American Funds [Member] Global Equity 60-40 Index [Member]	Dec. 31, 2011 European Funds (Not Including UK) [Member] Global Equity 60-40 Index [Member]	Dec. 31, 2011 Japanese Funds [Member] Global Equity 60-40 Index [Member]	Dec. 31, 2011 Pacific Basin Funds (Not Including Japan) [Member] Global Equity 60-40 Index [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plans assets	$ 24,414	$ 22,843	$ 21,832	$ 280	$ 429	$ 2,126	[1]	$ 2,607	[1]	$ 3,937	[2]	$ 4,179	[2]	$ 4,514	[3]	$ 4,409	[3]	$ 7,872	[4]	$ 6,346	[4]	$ 2,696	[5]	$ 2,071	[5]	$ 1,743	[6]	$ 1,639	[6]	$ 1,246	[7]	$ 1,163	[7]	$ 18,654	$ 17,271	$ 280	$ 429	$ 2,126	[1]	$ 2,607	[1]	$ 3,937	[2]	$ 4,179	[2]	$ 7,872	[4]	$ 6,346	[4]	$ 2,696	[5]	$ 2,071	[5]	$ 1,743	[6]	$ 1,639	[6]				[1]		[2]		[3]		[4]		[5]		[6]		[7]	$ 5,760	$ 5,572	$ 4,514	[3]	$ 4,409	[3]	$ 1,246	[7]	$ 1,163	[7]
Investment allocation percentage in funds																																																																																				60.00%	40.00%	14.00%	14.00%	6.00%	6.00%
Investment period (in years) of the asset category														6				15				15

[1] This fund invests in a mix of equity shares, bonds, property and cash. Only the equity investments are included in this line with the remaining being allocated to other appropriate categories. The fund is actively managed against its benchmark of the CAPS Balanced Pooled Fund Median. A prudent approach of diversification by both location and investment type is employed by the fund and both active stock selection and asset allocation are used to add value.

[2] This index fund invests 60% in the UK Equity Index Fund and 40% in overseas index funds. The overseas portion has a target allocation of 14% in North American funds, 14% in European funds (not including the UK), 6% in Japanese funds, and 6% in Pacific Basin funds (not including Japan).

[3] This category invests in 6 year Fixed Income investments with Delta Lloyd.

[4] This category invests in the M&G All Stocks Corporate Bond Fund and the Legal & General (LG) AAA Fixed interest—Over 15 Year Fund. These funds, respectively, invest primarily in investment grade corporate bonds, as well as other debt instruments, including higher yielding corporate bonds, government debt, convertible and preferred stocks, money market instruments and equities; and in long-dated sterling denominated AAA-rated corporate bonds, as well as smaller holdings in gilts—both providing a fixed rate of interest.

[5] This category invests mainly in long term gilts through the LG Over 15 Year Gilts Index and the M&G PP Discretionary Fund.

[6] This category invests in the M&G UK Property Fund. The fund invests directly in commercial properties in the UK and is actively managed against its performance benchmark of the BNY Mellon CAPS Pooled Fund Property Median. The fund is well diversified investing in the retail, office, and industrial sectors of the market. A small portion of this category is also held in the M&G PP Discretionary Fund.

[7] This category invests in insurance policies in the name of the individual plan members.