Postretirement Benefit Plans (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Postretirement Benefit Plan (Additional Textual) [Abstract]
Balance of trust assets	$ 1,694,000
U.S Plans [Member]
Postretirement benefit plan (Textual) [Abstract]
Expected payment related to Nonqualified plan	174,000
Payments related to non-qualified plans	107,000
U.K Plan [Member]
Postretirement benefit plan (Textual) [Abstract]
Company's expected contribution to qualified plan	986,000
Employer contributions	279,000
Retirement Savings Plans [Member]
Postretirement benefit plan (Textual) [Abstract]
Defined contribution plan expense	1,077,000	1,054,000
Profit Sharing Plan [Member]
Postretirement benefit plan (Textual) [Abstract]
Defined contribution plan expense	$ 1,325,000	$ 1,529,000