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Long-Term Debt - Summary (Details) - USD ($) $ in Thousands	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	May 30, 2017
Debt Instrument [Line Items]
Total long-term debt	$ 496,923	$ 631,568	$ 636,222
Deferred finance costs, net	3,100	3,400	3,800
Revolving Unsecured Credit Facility due 2024 \| Line of Credit
Debt Instrument [Line Items]
Total long-term debt	200,000	335,000	340,000
5.375% senior unsecured notes due 2024 \| Senior Notes
Debt Instrument [Line Items]
Total long-term debt	$ 296,923	$ 296,568	$ 296,222
Stated interest rate (as a percent)	5.375%			5.375%