Long-Term Debt - Components Table (Details) - USD ($) $ in Thousands	Mar. 31, 2017	Dec. 31, 2016	Jul. 28, 2014	Nov. 19, 2013
Long-Term Debt
Total long-term debt	$ 996,172	$ 502,539
Revolving Credit Facility
Long-Term Debt
Total long-term debt	$ 504,900	$ 14,100
Weighted average combined interest rate	2.20%	4.00%
Senior Notes 5.125 Percent Due 2022
Long-Term Debt
Total long-term debt	$ 247,535	$ 247,371
Interest rate, as a percentage	5.125%
Aggregate principle amount	$ 250,000		$ 250,000
Capitalized debt issuance costs	2,500	2,600
Convertible Senior Notes 1.00 percent due 2020
Long-Term Debt
Total long-term debt	$ 243,737	241,068
Effective interest rate percentage				5.26%
Interest rate, as a percentage	1.00%
Aggregate principle amount	$ 287,500
Unamortized discount and capitalized debt issuance costs	$ 43,763	$ 46,432