Fair Value of Financial Instruments - Fair Value Disclosures (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019	Mar. 31, 2019
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents	$ 31,833	$ 16,283	$ 23,972
Long-Term Debt (Excluding Debt Issuance Costs)	2,660,599	2,754,443
Long-term Debt, Fair Value	2,308,846	2,619,676
Carrying Amount
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Cash and Cash Equivalents	31,833	16,283
Long-Term Debt (Excluding Debt Issuance Costs)	$ 2,676,617	$ 2,763,433