Long-Term Debt - Maturity Schedule (Details) - Senior convertible notes, including interest
Sep. 30, 2016
USD ($)
Debt Instrument [Line Items]  
Total $ 253,000,000
2016 2,875,000
2017 5,750,000
2018 5,750,000
2019 5,750,000
2020 $ 232,875,000