Notes Payable (New Zealand Corporate Credit Facility) (Narrative) (Details) In Millions, unless otherwise specified	12 Months Ended			12 Months Ended
	Dec. 31, 2012 Previous New Zealand Corporate Credit Facility [Member]	Feb. 08, 2012 Previous New Zealand Corporate Credit Facility [Member] USD ($)	Feb. 07, 2012 Previous New Zealand Corporate Credit Facility [Member] NZD	Dec. 31, 2012 New Zealand Corporate Credit Facility [Member] USD ($)	Dec. 31, 2012 New Zealand Corporate Credit Facility [Member] NZD
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity		$ 36.9	45.0	$ 32.8	40.0
Line of credit facility, term				3 years	3 years
Line of credit facility, decrease in maximum borrowing capacity				$ 4.1	5.0
Increase in spread on variable interest rate	0.55%
Spread on variable interest rate				2.00%	2.00%
Line of credit facility charge	0.30%			0.40%	0.40%