Equity Investments (Schedule Of Summarized Aggregated Financial Information Related To The Subsidiaries) (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Equity Investments [Abstract]
Revenues	$ 53,159	$ 193,521	$ 141,705
Operating income	30,463	97,954	93,324
Net income	30,463	93,215	93,005
Current assets	16,682	39,754	25,352
Total assets	537,251	591,761	594,645
Current liabilities	706	11,012	6,434
Total liabilities	$ 5,320	$ 27,163	$ 19,695