Supplemental Information (Expenses) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Summary of expenses in statements of operations
Research and development	$ 64,600,000	$ 62,300,000	$ 60,700,000
Advertising, promotions and marketing	41,000,000	42,500,000	41,900,000
Cooperative advertising expenditures	14,700,000	13,700,000	13,100,000
Rent expense	$ 57,900,000	53,500,000	$ 50,500,000
Discontinued Operations [Member]
Summary of expenses in statements of operations
Advertising, promotions and marketing		0
Rent expense		$ 0