Contractual interest rate for funds borrowed, under the debt agreement.

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The amount of debt premium that was originally recognized at the issuance of the instrument that has yet to be amortized.

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Carrying amount of long-term debt, net of unamortized discount or premium, excluding amounts to be repaid within one year or the normal operating cycle, if longer (current maturities). Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Carrying amount of collateralized debt obligations with maturities initially due after one year or beyond the operating cycle, if longer, excluding the current portion. Obligations include, but not limited to, mortgage loans, chattel loans, and other borrowings secured by assets.

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Carrying value as of the balance sheet date of uncollateralized debt obligation (with maturities initially due after one year or beyond the operating cycle if longer), excluding current portion.

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Debt (Schedule Of Obligations Under Debt Arrangements) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013	Nov. 18, 2010	Mar. 31, 2014 7.875% Senior Unsecured Notes [Member]	Dec. 31, 2013 7.875% Senior Unsecured Notes [Member]	Mar. 31, 2014 Five Point Seventy Five Percentage Senior Unsecured Notes [Member]	Dec. 31, 2013 Five Point Seventy Five Percentage Senior Unsecured Notes [Member]	Feb. 08, 2013 Five Point Seventy Five Percentage Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Senior secured credit facility	$ 640,500	$ 582,800
Senior unsecured notes	700,740	700,772		350,740	350,772	350,000	350,000
Senior unsecured notes, stated rate			7.875%	7.875%	7.875%	5.75%	5.75%	5.75%
Senior unsecured notes, unamortized premium				740	772
Total long-term debt	$ 1,341,240	$ 1,283,572