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
Income Statement [Line Items]
Net income from continuing operations	$ (18,506)	$ (11,144)	$ 26,963	$ 30,528
Loss from discontinued operations, net of tax	(795)	(650)	(1,968)	(1,783)
Net income	$ (19,301)	$ (11,794)	$ 24,995	$ 28,745
Average common shares outstanding:
Average common shares outstanding - basic (in shares)	30,429	28,815	29,563	28,787
Additional shares for stock-based compensation plans	0	0	65	59
Average common shares outstanding - diluted (in shares)	30,429	28,815	29,628	28,846
Earnings from continuing operations per share of common stock:
Basic (in dollars per share)	$ (0.61)	$ (0.39)	$ 0.91	$ 1.06
Diluted (in dollars per share)	(0.61)	(0.39)	0.91	1.06
Loss from discontinued operations per share of common stock:
Basic (in dollars per share)	(0.02)	(0.02)	(0.07)	(0.06)
Diluted (in dollars per share)	(0.02)	(0.02)	(0.07)	(0.06)
Earnings (loss) per share of common stock
Basic (in dollars per share)	(0.63)	(0.41)	0.84	1.00
Diluted (in dollars per share)	$ (0.63)	$ (0.41)	$ 0.84	$ 1.00
Antidilutive shares	69	73	1	4
Discontinued Operations, Held-for-sale [Member] | Gill Ranch [Member]
Income Statement [Line Items]
Loss from discontinued operations, net of tax	$ (795)	$ (650)	$ (1,968)	$ (1,783)
Loss from discontinued operations per share of common stock:
Basic (in dollars per share)	$ (0.02)	$ (0.02)	$ (0.07)	$ (0.06)
Diluted (in dollars per share)	$ (0.02)	$ (0.02)	$ (0.07)	$ (0.06)