Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Income Statement [Line Items]
Net income from continuing operations	$ (5,132)	$ 2,051	$ 43,144	$ 45,469
Loss from discontinued operations, net of tax	280	(956)	(498)	(1,173)
Net income	$ (4,852)	$ 1,095	$ 42,646	$ 44,296
Average common shares outstanding:
Average common shares outstanding - basic (in shares)	30,537	29,337	30,514	29,123
Additional shares for stock-based compensation plans	0	57	45	63
Average common shares outstanding - diluted (in shares)	30,537	29,394	30,559	29,186
Earnings from continuing operations per share of common stock:
Basic (in dollars per share)	$ (0.17)	$ 0.07	$ 1.41	$ 1.56
Diluted (in dollars per share)	(0.17)	0.07	1.41	1.56
Loss from discontinued operations per share of common stock:
Basic (in dollars per share)	0.01	(0.03)	(0.01)	(0.04)
Diluted (in dollars per share)	0.01	(0.03)	(0.01)	(0.04)
Earnings (loss) per share of common stock
Basic (in dollars per share)	(0.16)	0.04	1.40	1.52
Diluted (in dollars per share)	$ (0.16)	$ 0.04	$ 1.40	$ 1.52
Antidilutive shares	41	1	0	2
Discontinued Operations, Held-for-sale [Member] | Gill Ranch [Member]
Income Statement [Line Items]
Loss from discontinued operations, net of tax	$ 280	$ (956)	$ (498)	$ (1,173)
Loss from discontinued operations per share of common stock:
Basic (in dollars per share)	$ 0.01	$ (0.03)	$ (0.01)	$ (0.04)
Diluted (in dollars per share)	$ 0.01	$ (0.03)	$ (0.01)	$ (0.04)