Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		37 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2017
Stockholders' Equity
Cost of shares of common stock repurchased	$ 237,162	$ 1,056	$ 241,283	$ 1,056
Common Stock
Stockholders' Equity
Authorized stock repurchase shares	6,975,323		6,975,323		6,975,323
Share Price	$ 34		$ 34		$ 34
Authorized stock repurchase amount	$ 500,000		$ 500,000		$ 500,000	$ 50,000
Shares of common stock repurchased	6,975,000	51,000	7,213,000	51,000	8,029,000
Cost of shares of common stock repurchased	$ 237,162	$ 1,056	$ 241,283	$ 1,056	$ 256,231