Uncertain Tax Positions (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011
Uncertain Tax Positions [Abstract]
Unrecognized tax benefits that would impact effective tax rate			$ 3,400,000	$ 2,100,000
Reconciliation of unrecognized tax benefits [Roll Forward]
Balance, beginning of period		2,060,000
Gross increases - current year tax positions		1,343,000
Gross increases - tax positions from prior periods		4,000
Balance, end of period	3,407,000	3,407,000
Interest and penalties accrued [Abstract]
Accrual for interest and penalties				100,000
Income taxes paid [Abstract]
Income taxes paid	19,300,000	33,800,000
Datac Instrumentation Limited [Member]
Business Acquisition [Line Items]
Escrow account balance	5,500,000	5,500,000
Tax credits and other various deductions [Member]
Significant Change in Unrecognized Tax Benefits is Reasonably Possible [Line Items]
Estimated change in unrecognized tax benefits expected within the next twelve months	$ 400,000	$ 400,000