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Long-Term Debt (Details 1) - USD ($) $ in Thousands | 3 Months Ended |  |  |
--- | --- | --- | --- | ---
Mar. 31, 2016 | Dec. 31, 2015 | Sep. 30, 2014 | Jun. 30, 2014
Carrying value of Notes related discount and equity component |  |  |  |
Amortization period of underwriters fees and debt issuance costs | 8 years |  |  |
5.00% Senior Note [Member] |  |  |  |
Carrying value of Notes related discount and equity component |  |  |  |
Debt Instrument, Face Amount | $ 550,000 | $ 550,000 | $ 200,000 | $ 350,000
Debt Instrument, Interest Rate, Stated Percentage | 5.00% |  |  |
Additional borrowings discount from face value | 1.50% |  |  |
Debt Instrument, Maturity Date Range, End | Jun. 01, 2022 |  |  |
Debt Instrument, Redemption Price, Percentage of Principal Amount Redeemed | 35.00% |  |  |
Redemption price percentage of principal outstanding and accrued unpaid interest | 105.00% |  |  |
Redemption price percentage of principal redeemed | 100.00% |  |  |

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