Current and Long-Term Debt - Components of Long-Term Debt (Details) - USD ($)	9 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Apr. 04, 2017	Nov. 19, 2013
Long-Term Debt
Total Debt	$ 893,551,000	$ 739,475,000
Less: Current portion	(119,694,000)	0
Total Long-Term Debt	773,857,000	739,475,000
Revolving Credit Facility
Long-Term Debt
Total Debt	0	167,227,000
Term Loan Facility
Long-Term Debt
Total Debt	481,827,000	0
Aggregate principle amount	498,700,000
Unamortized discount and capitalized debt issuance costs	16,900,000
Quarterly payments	5,000,000.0
Senior Notes 5.50 Percent Due 2025
Long-Term Debt
Total Debt	$ 297,030,000	$ 296,545,000
Interest rate, as a percentage	5.50%	5.50%	5.50%
Aggregate principle amount	$ 300,000,000.0		$ 300,000,000.0
Capitalized debt issuance costs	3,000,000.0	$ 3,500,000
Convertible Senior Notes 1.00 percent due December 2020
Long-Term Debt
Total Debt	$ 114,694,000	$ 275,703,000
Interest rate, as a percentage	1.00%	1.00%		1.00%
Aggregate principle amount	$ 115,600,000	$ 287,500,000		$ 287,500,000
Unamortized discount and capitalized debt issuance costs	$ 874,000	$ 11,797,000