Property, Plant And Equipment (Details) (USD $)	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011	Dec. 31, 2011
Property, Plant And Equipment [Abstract]
Land and land improvements	$ 27,036,000		$ 27,036,000
Buildings	69,182,000		69,182,000
Leasehold improvements	17,019,000		16,696,000
Equipment	193,539,000		182,987,000
Furniture and fixtures	32,722,000		31,412,000
Construction in progress	23,514,000		25,828,000
Property, plant and equipment, gross	363,012,000		353,141,000
Accumulated depreciation and amortization	(156,614,000)		(149,419,000)
Property, plant and equipment, net	206,398,000		203,722,000
Depreciation and amortization expense	$ 7,200,000	$ 6,900,000