Postretirement Benefit Plans - Company's Asset Allocations for its U.K. Pension Plans by Asset Category (Detail) (United Kingdom [Member], USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Total	$ 22,204	$ 18,390	$ 15,695
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	412	845
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	19,366	15,108
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	2,426	2,437
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	412	845
Cash [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	412	845
Cash [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Cash [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Pooled Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	15,397	11,979
Pooled Pension Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Pooled Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	15,397	11,979
Pooled Pension Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Pooled Fixed Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,550	2,677
Pooled Fixed Pension Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Pooled Fixed Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	3,550	2,677
Pooled Fixed Pension Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Real Estate Pooled Pension Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	419	452
Real Estate Pooled Pension Funds [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Real Estate Pooled Pension Funds [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	419	452
Real Estate Pooled Pension Funds [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Insurance Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	2,426	2,437
Insurance Contract [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Insurance Contract [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total
Insurance Contract [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Total	$ 2,426	$ 2,437