Recent Accounting Developments - Narrative (Details) - USD ($) $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Jan. 01, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201602Member
Change in Accounting Principle, Accounting Standards Update, Transition Option Elected [Extensible List]	save:AccountingStandardsUpdate201613CumulativeEffectPeriodOfAdoption
Retained earnings	$ 1,781,322	$ 1,955,187
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Accounts receivable, allowance for credit loss				$ 1,600
Retained earnings		$ (1,600)