Goodwill and Other Intangible Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Goodwill and indefinite life intangible assets:
Goodwill	$ 112,446	$ 112,446
Trademarks and trade names	24,599	24,599
Total goodwill and trademarks and trade names	137,045	137,045
Finite life intangible assets [Abstract]
Gross carrying amount	128,304	139,990
Accumulated amortization	$ 85,894	89,527
Weighted average amortization period	15 years
Amortization expense	$ 8,600	8,400	$ 7,800
Annual estimated amortization expense [Abstract]
2016	8,000
2017	8,000
2018	8,000
2019	8,000
2020	8,000
Writeoff of fully amortized intangible assets	12,000
Scanner technology [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	46,482	46,482
Accumulated amortization	$ 33,590	30,557
Weighted average amortization period	18 years
Developed technology [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	$ 22,500	22,500
Accumulated amortization	$ 17,558	16,734
Weighted average amortization period	20 years
Distribution network [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	$ 11,598	11,598
Accumulated amortization	$ 11,096	10,594
Weighted average amortization period	15 years
Trademarks [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	$ 2,409	14,404
Accumulated amortization	$ 879	12,461
Weighted average amortization period	15 years
Other [Member]
Finite life intangible assets [Abstract]
Gross carrying amount	$ 45,315	45,006
Accumulated amortization	$ 22,771	$ 19,181
Weighted average amortization period	8 years