Basis of Presentation - Recently Adopted Accounting Standards (Details) - USD ($) $ in Thousands	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Operating lease right-of-use assets	$ 41,513	$ 45,792	$ 41,453
Total operating lease liabilities	41,912	$ 46,342	$ 41,797
Remaining borrowing capacity	$ 300,000