Basis of Presentation and Accounting Policies - Deferred Gains (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jan. 01, 2019
Deferred Gains [Roll Forward]
Balance at beginning of period	$ 12,008	$ 43,664
Impact of adoption of accounting principle	0
Balance at end of period	11,016	12,338
Gain (Loss) on Disposition of Assets
Deferred Gains [Roll Forward]
Amortization of deferred gains included in gains on asset dispositions, net	$ (992)	$ (2,119)
Accounting Standards Update 2016-02 | Sale-Leaseback | Retained Earnings
Deferred Gains [Roll Forward]
Impact of adoption of accounting principle			$ (29,207)