Long-Term Debt - Narrative (Details)	3 Months Ended		6 Months Ended
	Jun. 30, 2018 USD ($) loan	Dec. 31, 2017 USD ($) loan	Jun. 30, 2018 USD ($)
U.K. Working Capital Loans
Debt Instrument [Line Items]
Borrowings outstanding	$ 20,400,000		$ 20,400,000
Current maturities of long-term debt	$ 2,100,000		2,100,000
Mortgage Loans
Debt Instrument [Line Items]
Number of loans as per loan agreements | loan	61
Aggregate principal amount	$ 432,700,000.0		432,700,000.0
Borrowings outstanding	365,500,000		365,500,000
Current maturities of long-term debt	46,000,000		46,000,000
Additional net borrowings			42,700,000
Principal payments			27,200,000
Fixed interest rate borrowings	83,200,000	$ 86,800,000	83,200,000
Fair value of fixed interest rate borrowings	$ 85,000,000	92,900,000	85,000,000
U.K. Notes
Debt Instrument [Line Items]
Number of loans as per loan agreements | loan	18
Borrowings outstanding	$ 80,700,000		80,700,000
Current maturities of long-term debt	$ 7,900,000		7,900,000
Additional net borrowings			12,100,000
Principal payments			8,600,000
Maturity date of notes	Sep. 01, 2034
Brazil Note
Debt Instrument [Line Items]
Borrowings outstanding	$ 2,600,000		2,600,000
Current maturities of long-term debt	300,000		300,000
Additional net borrowings			0
Principal payments			300,000
Brazilian Third Party Loan
Debt Instrument [Line Items]
Borrowings outstanding	5,700,000		5,700,000
Additional net borrowings			0
5.00% Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount	$ 550,000,000	$ 550,000,000	$ 550,000,000
Interest rate	5.00%	5.00%	5.00%
Fair value of long-term debt	$ 548,300,000	$ 567,900,000	$ 548,300,000
5.25% Senior Notes
Debt Instrument [Line Items]
Aggregate principal amount	$ 300,000,000	$ 300,000,000	$ 300,000,000
Interest rate	5.25%	5.25%	5.25%
Fair value of long-term debt	$ 291,200,000	$ 310,900,000	$ 291,200,000
Revolving Credit Facility | U.K. Working Capital Loans
Debt Instrument [Line Items]
Number of loans as per loan agreements | loan		2
Borrowings made under short-term debt agreement			26,400,000
Principal payments under short-term debt agreement			26,600,000
Revolving Credit Facility | U.K. Working Capital Loan 1
Debt Instrument [Line Items]
Short-term loan	13,100,000	$ 13,100,000	13,100,000
Revolving Credit Facility | U.K. Working Capital Loan 2
Debt Instrument [Line Items]
Short-term loan	13,400,000	13,400,000	13,400,000
Revolving Credit Facility | Brazilian Short-Term Financing Arrangement
Debt Instrument [Line Items]
Short-term loan	$ 1,700,000		1,700,000
Borrowings made under short-term debt agreement			2,400,000
Principal payments under short-term debt agreement			$ 300,000
Revolving Credit Facility | U.S. Short-Term Financing Arrangement
Debt Instrument [Line Items]
Short-term loan		$ 24,700,000