Summary of Fair Value of Plan Assets by Asset Category (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	$ 33,457		$ 28,629		$ 24,590
UNITED KINGDOM | Mutual Funds | Balanced Fund
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	16,260	[1]	14,266	[2]
UNITED KINGDOM | Mutual Funds | Growth Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	17,060	[3]	14,244	[4]
UNITED KINGDOM | Cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	137		119
JAPAN
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	554		827		582
JAPAN | Insurance Contracts
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	554	[5]	827	[5]
Fair Value, Inputs, Level 1 | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	137		119
Fair Value, Inputs, Level 1 | UNITED KINGDOM | Cash
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	137		119
Fair value, Inputs, Level 2 | UNITED KINGDOM
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	33,320		28,510
Fair value, Inputs, Level 2 | UNITED KINGDOM | Mutual Funds | Balanced Fund
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	16,260	[1]	14,266	[2]
Fair value, Inputs, Level 2 | UNITED KINGDOM | Mutual Funds | Growth Funds
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	17,060	[3]	14,244	[4]
Fair value, Inputs, Level 2 | JAPAN
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	554		827
Fair value, Inputs, Level 2 | JAPAN | Insurance Contracts
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Fair Value of Plan Assets	$ 554	[5]	$ 827	[5]

[1] This class comprises a diversified portfolio of global investments which seeks a balanced return between capital growth and fixed income and is allocated on a weighted average basis as follows: equities (51%), debt (33%), other assets (8%) and cash (8%).

[2] This class comprises a diversified portfolio of global investments which seeks a balanced return between capital growth and fixed income and is allocated on a weighted average basis as follows: equities (47%), debt (41%), other assets (9%) and cash (3%).

[3] This class comprises a diversified portfolio of global investments which seeks long-term capital growth and is allocated on a weighted average basis as follows: equities (70%), debt (14%), other assets (9%) and cash (7%).

[4] This class comprises a diversified portfolio of global investments which seeks long-term capital growth and is allocated on a weighted average basis as follows: equities (68%), other assets (10%), debt (21%), and cash (1%).

[5] This class represents funds invested in insurance contracts.