Income Taxes (Narrative) (Details) - USD ($)	1 Months Ended	12 Months Ended
	Feb. 29, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 15, 2009
Income Tax Contingency [Line Items]
Tax Cuts and Jobs Act of 2017, limitation on use of net operating losses to percent of taxable income		80.00%
U.S. tax reform		$ (16,200,000)	$ 0	$ 0
Transition tax on accumulated foreign earnings, amount		46,000,000
Change in enacted tax rate, amount		(62,000,000)
Tax Cuts and Jobs Act of 2017, transition tax for accumulated foreign earnings		296,000,000
Deferred tax assets, valuation allowance		157,400,000	177,100,000
Deferred tax assets, tax loss carryforwards		202,300,000	238,700,000
Operating loss carryforwards		238,200,000
Income tax expense (benefit)		15,800,000	(3,700,000)	(14,800,000)
Tax Cuts and Jobs Act of 2017, income tax benefit		1,200,000
Tax Cuts and Jobs Act of 2017, provisional liability		1,100,000
Unrecognized tax benefits that would impact effective tax rate		25,900,000	31,000,000	22,700,000
Unrecognized tax benefits, income tax penalties expense		(300,000)	300,000	(1,400,000)
Unrecognized tax benefits, interest on income taxes expense		(700,000)	300,000	(3,000,000)
Recognized liabilities for penalties		1,500,000	1,800,000
Recognized liabilities for expense		2,200,000	$ 2,900,000	$ 3,500,000
Significant change in unrecognized tax benefits is reasonably possible, amount of unrecorded benefit		2,000,000
Proposed cumulative taxable income adjustment	$ 50,000,000
North America | Subordinated Convertible Notes Due 2029
Income Tax Contingency [Line Items]
Debt principal amount					$ 429,500,000.0
Valuation Allowance
Income Tax Contingency [Line Items]
Income tax expense (benefit)		(1,600,000)
Valuation Allowance | New Zealand
Income Tax Contingency [Line Items]
Deferred tax assets, net		5,700,000
Taxing Jurisdictions
Income Tax Contingency [Line Items]
Deferred tax assets, tax loss carryforwards		62,800,000
Foreign Country
Income Tax Contingency [Line Items]
Operating loss carryforwards		$ 535,000,000