XML 28 R47.htm IDEA: XBRL DOCUMENT v2.4.1.9
Fair Value Measurements (Details) (Senior Notes [Member], USD $)
In Millions, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Senior Notes Due 2017 [Member]
      
Fair value of senior notes      
Fair value of senior notes $ 153.0us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2017Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 $ 256.7us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2017Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 $ 258.1us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2017Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Carrying value of senior notes 250.0us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2017Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 250.0us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2017Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 250.0us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2017Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Senior Notes Due 2020 [Member]
      
Fair value of senior notes      
Fair value of senior notes 133.1us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2020Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 239.1us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2020Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 244.4us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2020Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Carrying value of senior notes 222.8us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2020Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 222.4us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2020Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 221.1us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2020Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Senior Notes Due 2022 [Member]
      
Fair value of senior notes      
Fair value of senior notes 198.0us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2022Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 409.0us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2022Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 424.0us-gaap_DebtInstrumentFairValue
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2022Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember
Carrying value of senior notes $ 404.5us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2022Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 $ 404.9us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2022Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember		 $ 405.4us-gaap_SeniorLongTermNotes
/ us-gaap_DebtInstrumentAxis
= sfy_SeniorNotesDue2022Member
/ us-gaap_LongtermDebtTypeAxis
= us-gaap_SeniorNotesMember