Pensions and Postretirement Benefits Other than Pensions (Details 7) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Assets of U.S and U.K plans using the Fair Value Hierarchy
Total	$ 907,131	$ 928,323	$ 868,180
U.S. Plans [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	16,106	22,537
Equity securities	412,809	456,213
Fixed income securities	251,302	220,077
Total	680,217	698,827
U.K Plan [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	796	2,854
Equity securities	126,126	138,141
Fixed income securities	66,491	75,364
Other investments	31,213	10,814
Total	224,626	227,173
Level 1 [Member] | U.S. Plans [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	16,106	22,537
Equity securities	168,240	171,889
Fixed income securities	83,274	72,984
Total	267,620	267,410
Level 1 [Member] | U.K Plan [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	796	2,854
Equity securities	126,126	138,141
Fixed income securities	66,491	75,364
Other investments	18,379	0
Total	211,792	216,359
Level 2 [Member] | U.S. Plans [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	0	0
Equity securities	244,569	284,324
Fixed income securities	168,028	147,093
Total	412,597	431,417
Level 2 [Member] | U.K Plan [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	0	0
Equity securities	0	0
Fixed income securities	0	0
Other investments	0	0
Total	0	0
Level 3 [Member] | U.S. Plans [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	0	0
Equity securities	0	0
Fixed income securities	0	0
Total	0	0
Level 3 [Member] | U.K Plan [Member]
Assets of U.S and U.K plans using the Fair Value Hierarchy
Cash & Cash Equivalents	0	0
Equity securities	0	0
Fixed income securities	0	0
Other investments	12,834	10,814	9,788
Total	$ 12,834	$ 10,814