Income Taxes (Schedule Of Components Of Net Deferred Tax Assets And Liabilities) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Current [Member]
Assets:
Accrued expenses	$ 20,377	$ 19,833
Accounts receivable reserves	2,591	1,153
Deferred revenue	8,697	5,872
Inventory basis differences	3,154	2,670
Share-based compensation	2,490	2,325
Other	171	13
Net operating loss carryforwards	65	500
Unrealized losses on foreign currency exchange contracts, interest rate swaps and investments		1,580
Total assets	37,545	33,946
Valuation allowance	(457)	(642)
Total assets, net of valuation allowance	37,088	33,304
Liabilities:
Other	(610)	(190)
Unrealized gains on foreign currency exchange	(2,603)	(1,303)
Total liabilities	(3,213)	(1,493)
Net deferred tax assets (liabilities)	33,875	31,811
Long-Term [Member]
Assets:
Accrued expenses	7,824	1,622
Deferred revenue	3,084	1,552
Inventory basis differences	347
Property-based differences	1,601	1,728
Share-based compensation	8,936	7,923
Other	255	150
Net operating loss carryforwards	4,368	4,182
Total assets	26,415	17,157
Valuation allowance	(4,221)	(4,559)
Total assets, net of valuation allowance	22,194	12,598
Liabilities:
Deferred instrument costs	(10,149)	(3,093)
Property-based differences	(33,978)	(25,823)
Intangible assst basis differences	(16,882)	(15,513)
Other	(517)	(790)
Total liabilities	(61,526)	(45,219)
Net deferred tax assets (liabilities)	$ (39,332)	$ (32,621)