Long-Term Debt (Schedule Of Long-Term Debt) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Debt Disclosure [Abstract]
Senior notes	$ 216,429	$ 227,143
Revolving credit facility	0	10,000
Capitalized lease and other obligations	2,904	3,264
Total long-term debt	219,333	240,407
Less: Current maturities	(38,619)	(38,978)
Total maturities due after one year	$ 180,714	$ 201,429