Special charges (Details) (USD $)	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012
Associated liabilities incurred related to plan [Roll Forward]
Beginning Balance		$ 0
Charged to expense		2,191,000
Paid or otherwise settled		(157,000)
Ending Balance	2,034,000	2,034,000
Severance and Personnel Costs [Member]
Associated liabilities incurred related to plan [Roll Forward]
Beginning Balance		0
Charged to expense		281,000
Paid or otherwise settled		(85,000)
Ending Balance	196,000	196,000
Other Exit Costs [Member]
Associated liabilities incurred related to plan [Roll Forward]
Beginning Balance		0
Charged to expense		1,910,000
Paid or otherwise settled		(72,000)
Ending Balance	1,838,000	1,838,000
Technology products segment [Member]
Special Charges [Line Items]
Special charges	300,000	1,900,000
Industrial products segment [Member]
Special Charges [Line Items]
Special charges	$ 1,900,000	$ 2,200,000