Earnings Per Common Share (EPS) - Basic EPS (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Earnings Per Share, Basic and Diluted [Abstract]
Net income (loss)	$ (3,398)	$ 6,859	$ 6,195	$ 16,619	$ 10,941	$ 5,269	$ 9,656	$ 32,828
Average common shares outstanding (in shares)	55,152			53,431			55,029	51,434
Basic EPS (in dollars per share)	$ (0.06)			$ 0.31			$ 0.18	$ 0.64