Significant Accounting Policies Significant Accounting Policies (Details) - USD ($) $ in Thousands	Jun. 30, 2021	Jan. 01, 2021	Dec. 31, 2020
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings	$ 2,972,362		$ 2,642,096
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Retained earnings		$ 68,300
Additional paid in capital		$ 68,300