Supplemental Guarantor Condensed Financial Information (Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Cash dividend paid	$ 35,600,000	$ 35,300,000	$ 35,400,000
5.75% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Interest rate on senior convertible notes	5.75%
Parent Company [Member]
Debt Instrument [Line Items]
Cash dividend paid	$ 0	$ 0	$ 0
North America [Member] | Parent Company [Member] | 5.75% Senior Notes due 2022 [Member]
Debt Instrument [Line Items]
Debt principal amount	$ 600,000,000
Debt maturity date	Dec. 31, 2022
North America [Member] | Parent Company [Member] | Senior Floating Notes Due In 2015 [Member]
Debt Instrument [Line Items]
Debt maturity date	Dec. 31, 2015