Income Taxes - Deferred Tax Assets and Liabilites By Segment (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Income Tax [Line Items]
Noncurrent deferred tax asset	$ 60,535	$ 54,686
Valuation allowance	(9,545)	(3,094)
Non-current deferred tax liability	(81,195)	(66,213)
Net deferred tax liability	(30,205)	(14,621)
North America
Income Tax [Line Items]
Noncurrent deferred tax asset	29,218	34,274
Valuation allowance	(2,267)	(2,244)
Non-current deferred tax liability	(61,486)	(59,194)
Net deferred tax liability	(34,535)	(27,164)
Europe And Africa
Income Tax [Line Items]
Noncurrent deferred tax asset	14,572	18,644
Valuation allowance	(891)	(850)
Non-current deferred tax liability	(10,293)	(7,019)
Net deferred tax asset	3,388	10,775
Australia And New Zealand
Income Tax [Line Items]
Noncurrent deferred tax asset	15,803
Valuation allowance	(6,387)
Non-current deferred tax liability	(9,416)
Corporate Segment
Income Tax [Line Items]
Noncurrent deferred tax asset	942	1,768
Net deferred tax asset	$ 942	$ 1,768