Segment Identifiable Assets (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	$ 4,586,313		$ 3,973,533		$ 3,911,334
Depreciation	66,235		57,995		64,823
Water & Fluid Solutions
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	3,792,188		3,409,556		3,205,774
Depreciation	42,419		37,449		44,063
Technical Products
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	651,693		728,969		716,092
Depreciation	17,826		17,544		19,035
Significant Reconciling Items
Segment Reporting, Asset Reconciling Item [Line Items]
Assets	142,432	[1]	(164,992)	[1]	(10,532)	[1]
Depreciation	$ 5,990	[1]	$ 3,002	[1]	$ 1,725	[1]

[1] All cash and cash equivalents are included in Other