Debt (Narrative) (Details) (USD $)	3 Months Ended		9 Months Ended								9 Months Ended	12 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Dec. 31, 2013	Sep. 30, 2014 7.25% Unsecured Notes due February 1, 2019 [Member]	Dec. 31, 2013 7.25% Unsecured Notes due February 1, 2019 [Member]	Jan. 31, 2009 7.25% Unsecured Notes due February 1, 2019 [Member]	Sep. 30, 2014 AUD $50 million portion of Revolver [Member]	Dec. 31, 2013 AUD $50 million portion of Revolver [Member]	Sep. 30, 2014 Other Indebtedness [Member]	Dec. 31, 2013 Other Indebtedness [Member]
Debt Instrument [Line Items]
Borrowings outstanding									$ 43,669,000	$ 44,625,000
Minimum interest rate											0.00%	0.00%
Maximum interest rate											6.00%	6.00%
Debt Instrument, Interest Rate, Stated Percentage								7.25%
Debt Instrument, Maturity year, start											Oct. 01, 2014	Jan. 01, 2014
Debt Instrument, Maturity year, end											Dec. 31, 2017	Dec. 31, 2017
Average borrowings outstanding	450,900,000	449,800,000	451,400,000	477,500,000
Weighted average interest rate of borrowings	7.00%	7.00%	7.00%	7.00%
Net interest expense incurred	8,800,000	8,600,000	24,900,000	25,600,000
Fair value of debt instrument						468,000,000	475,200,000
Carrying value of debt instrument	$ 398,204,000		$ 398,204,000		$ 397,893,000	$ 398,200,000	$ 397,900,000