Income Taxes (Schedule Of Additional Information Related To Unrecognized Uncertain Tax Positions) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Tax Disclosure [Abstract]
Gross unrecognized tax benefits on uncertain tax positions (reflected in current income tax and other noncurrent liability accounts in the balance sheet)	$ 3,255	$ 2,239	$ 910	$ 1,025
Deferred income tax assets related to unrecognized tax benefits on uncertain tax positions (reflected in deferred income tax accounts in the balance sheet)	(726)	(540)	(212)
Net unrecognized tax benefits on uncertain tax positions, which would impact the effective tax rate if recognized	2,529	1,699	698
Interest and penalties accrued on deductions taken relating to uncertain tax positions (approximately $150, $100 and $(300) reflected in income tax expense in the income statement in 2014, 2013 and 2012, respectively, with the balance shown in current income tax and other noncurrent liability accounts in the balance sheet)	310	156	60
Interest and penalties accrued on deductions taken relating to uncertain tax positions, reflected in income tax expense in the income statement	150	100	(300)
Related deferred income tax assets recognized on interest and penalties	(116)	(60)	(23)
Interest and penalties accrued on uncertain tax positions net of related deferred income tax benefits, which would impact the effective tax rate if recognized	194	96	37
Total net unrecognized tax benefits on uncertain tax positions reflected in the balance sheet, which would impact the effective tax rate if recognized	$ 2,723	$ 1,795	$ 735