Earnings (Loss) Per Common Share (EPS) - Basic EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Earnings Per Share, Basic and Diluted [Abstract]
Net income (loss)	$ (19,058)	$ (3,154)	$ 6,859	$ 6,195	$ (22,212)	$ 13,054
Average common shares outstanding (in shares)	55,406		55,017		55,326	54,967
Basic EPS (in dollars per share)	$ (0.34)		$ 0.12		$ (0.40)	$ 0.24