Per Share Data and Stockholders' Equity - Dilutive Effect on Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Weighted Average Shares
Weighted average common shares outstanding	43,078	42,673	42,995	42,708
Diluted earnings (loss) (shares)	44,203	42,994	43,456	42,964
From Continuing Operations
Earnings (loss)	$ 29,168	$ 15,301	$ 98,268	$ 30,409
Basic earnings (loss) per share (usd per share)	$ 0.68	$ 0.36	$ 2.28	$ 0.71
From Discontinued Operations
Earnings (loss)	$ (158)	$ (183)	$ (437)	$ (579)
Basic earnings (loss) per share (usd per share)	$ (0.01)	$ (0.01)	$ (0.01)	$ (0.01)
Net Income (Loss)
Earnings (loss)	$ 29,010	$ 15,118	$ 97,831	$ 29,830
Basic earnings (loss) per share (usd per share)	$ 0.67	$ 0.35	$ 2.27	$ 0.70
Effect of dilutive securities:
Earnings (loss) per share from continuing operations (usd per share)	0.66	0.36	2.26	0.71
Earnings (loss) per share from discontinued operations (usd per share)	0	(0.01)	(0.01)	(0.02)
Earnings (loss) per common share (usd per share)	$ 0.66	$ 0.35	$ 2.25	$ 0.69