Goodwill and Other Intangible Assets (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Goodwill and indefinite life intangible assets:
Goodwill	$ 112,446,000	$ 112,446,000
Trademarks and trade names	24,599,000	24,599,000
Total goodwill and trademarks and trade names	137,045,000	137,045,000
Finite life intangible assets [Abstract]
Gross carrying amount	139,990,000	148,206,000
Accumulated amortization	89,527,000	89,637,000
Weighted average	15 years
Amortization expense	8,400,000	7,800,000	7,900,000
Annual estimated amortization expense [Abstract]
2013	8,000,000
2014	8,000,000
2015	8,000,000
2016	8,000,000
2017	8,000,000
Scanner technology [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	46,482,000	46,482,000
Accumulated amortization	30,557,000	27,533,000
Weighted average	18 years
Developed technology [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	22,500,000	22,500,000
Accumulated amortization	16,734,000	15,909,000
Weighted average	20 years
Distribution network [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	11,598,000	11,598,000
Accumulated amortization	10,594,000	10,093,000
Weighted average	15 years
Trademarks [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	14,404,000	14,086,000
Accumulated amortization	12,461,000	11,660,000
Weighted average	15 years
Other [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	45,006,000	53,540,000
Accumulated amortization	$ 19,181,000	$ 24,442,000
Weighted average	8 years