Postretirement Benefit Plans (Details 12) (UNITED KINGDOM [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Company's asset allocations for its U.S. and U.K. pension plans
Total	$ 18,390	$ 15,695	$ 15,358
Level 1 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	845	494
Level 2 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	15,108	12,983
Level 3 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	2,437	2,218
Cash [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	845	494
Cash [Member] | Level 1 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	845	494
Cash [Member] | Level 2 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Cash [Member] | Level 3 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Pooled Pension Funds [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	11,979	8,959
Pooled Pension Funds [Member] | Level 1 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Pooled Pension Funds [Member] | Level 2 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	11,979	8,959
Pooled Pension Funds [Member] | Level 3 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Pooled Fixed Pension Funds [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	2,677	3,115
Pooled Fixed Pension Funds [Member] | Level 1 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Pooled Fixed Pension Funds [Member] | Level 2 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	2,677	3,115
Pooled Fixed Pension Funds [Member] | Level 3 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Real Estate Pooled Pension Funds [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	452	909
Real Estate Pooled Pension Funds [Member] | Level 1 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Real Estate Pooled Pension Funds [Member] | Level 2 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	452	909
Real Estate Pooled Pension Funds [Member] | Level 3 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Insurance Contracts [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	2,437	2,218
Insurance Contracts [Member] | Level 1 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Insurance Contracts [Member] | Level 2 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total
Insurance Contracts [Member] | Level 3 [Member]
Company's asset allocations for its U.S. and U.K. pension plans
Total	$ 2,437	$ 2,218