Postretirement Benefit Plans (Details Textual) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Postretirement benefit plan (Textual) [Abstract]
Balance of the trust assets	$ 1,429,000		$ 1,429,000
U.S Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected payment related to Nonqualified plan	268,000		268,000
Company's expected contribution to qualified plan	6,698,000		6,698,000
Contribution to the qualified plans			2,120,000
Payment related to the non-qualified plans			152,000
U.K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Company's expected contribution to qualified plan	940,000		940,000
Contribution to the qualified plans			507,000
Retirement Savings Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan expense	1,058,000	1,005,000	2,112,000	1,955,000
Profit Sharing Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan expense	$ 1,352,000	$ 1,510,000	$ 2,881,000	$ 2,660,000