Significant Accounting Policies, Share Repurchase Program (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended		12 Months Ended
	Mar. 31, 2020	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Significant Accounting Policies [Abstract]
Authorized amount of share repurchase program			$ 125,000
Shares repurchased (in shares)	1,500,000			535,000
Shares repurchased	$ 90,600	$ 90,548	$ 0	$ 34,400