Income Taxes (Schedule of Components of Net Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets
Accrued expenses	$ 25,296	$ 22,652
Accounts receivable reserves	617	776
Deferred revenue	6,073	7,637
Inventory basis differences	3,315	2,787
Property-based differences	3,113	1,652
Share-based compensation	10,593	9,267
Other	1,160	2,314
Net operating loss carryforwards	4,045	3,208
Tax credit carryforwards	12,276	10,226
Unrealized losses on foreign currency exchange contracts and investments	20	404
Total assets	66,508	60,923
Valuation allowance	(9,454)	(6,212)
Total assets, net of valuation allowance	57,054	54,711
Liabilities
Customer acquisition costs	(28,519)	(24,323)
Property-based differences	(33,802)	(32,494)
Intangible asset basis differences	(14,513)	(13,454)
Other	(3,961)	(3,319)
Unrealized gains on foreign currency exchange contracts and investments	(1,183)	(1,907)
Total liabilities	(81,978)	(75,497)
Net deferred tax assets (liabilities)	$ (24,924)	$ (20,786)