Fair Value of Financial Instruments (Details) - USD ($)	Mar. 31, 2018	Dec. 31, 2017
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, fair value	$ 2,900,000	$ 7,800,000
Derivative liability, fair value	16,700,000	17,000,000
Long-term debt, fair value	317,800,000	324,700,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Derivative asset, fair value	2,900,000	7,800,000
Derivative liability, fair value	$ 16,700,000	$ 17,000,000
Senior Unsecured Term Loan Due January 15, 2020, 1.056% [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, interest rate, percent	1.056%	1.056%
5 7/8% Senior Notes due 2021 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Debt instrument, interest rate, percent	5.875%	5.875%
Debt instrument, face amount	$ 305,000,000	$ 305,300,000