Stockholders' Equity - Stock Repurchase Program (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended			12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Aug. 15, 2019	Aug. 14, 2019
Stockholders’ Equity
Average purchase price per share for share repurchase (in dollars per share)				$ 16.59	$ 17.82
Aggregate cost				$ 20,845	$ 93,369	$ 147,422
Additional authorized repurchase amount							$ 64,200
Remaining authorized repurchase amount	$ 86,200			86,200			$ 100,000	$ 35,800
Cash and cash equivalent balance to be maintained	$ 100,000			$ 100,000
Common Stock
Stockholders’ Equity
Shares repurchased during the period (in shares)				1,263,159	5,238,566	8,450,294
Treasury stock, shares, retired (in shares)	1,263,159		5,238,566
Retirement of treasury stock	$ 20,800	$ 93,400		$ 20,845	$ 93,369	$ 147,422