Business Segments And Geographic Area Information (Schedule Of Operating Property And Revenue By Geographic Area) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Segment Reporting Information [Line Items]
Total property and equipment	$ 202,778				$ 203,780				$ 202,778	$ 203,780
Total revenue	65,117	63,934	62,948	62,431	57,421	66,554	66,960	54,044	254,430	244,979	229,322
Australia [Member]
Segment Reporting Information [Line Items]
Total property and equipment	106,020				106,263				106,020	106,263
Total revenue									108,320	110,742	93,417
New Zealand [Member]
Segment Reporting Information [Line Items]
Total property and equipment	35,456				33,322				35,456	33,322
Total revenue									24,608	22,247	25,339
United States [Member]
Segment Reporting Information [Line Items]
Total property and equipment	61,302				64,195				61,302	64,195
Total revenue									$ 121,502	$ 111,990	$ 110,566