Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Earnings Per Share [Abstract]
Income from continuing operations		$ 37,592	$ 22,123	$ 32,396	$ 73,562
Loss from discontinued operations, net of tax		(256)	(4,233)	(5,077)	(10,744)
Net income		37,336	17,890	27,319	62,818
Dividends and undistributed income allocated to participating shares		(1,130)	(739)	(905)	(2,294)
Income from continuing operations to common shares - basic		36,462	21,384	31,491	71,268
Effect of reallocating undistributed income from continuing operations to participating shares		0	8	0	41
Income from continuing operations to common shares - diluted		$ 36,462	$ 21,392	$ 31,491	$ 71,309
Weighted average common shares - basic (in shares)		17,220	18,798	17,775	20,792
Dilutive effect of share-based payment awards (in shares)		9	53	14	87
Dilutive effect of convertible debt (in shares)		0	170	0	307
Weighted average common shares - diluted (in shares)	[1]	17,229	19,021	17,789	21,186
Basic earnings (loss) per common share:
Continuing operations (in usd per share)		$ 2.12	$ 1.14	$ 1.77	$ 3.43
Discontinued operations (in usd per share)		(0.02)	(0.23)	(0.28)	(0.52)
Basic earnings per common share (in usd per share)		2.10	0.91	1.49	2.91
Diluted earnings (loss) per common share:
Continuing operations (in usd per share)		2.12	1.12	1.77	3.37
Discontinued operations (in usd per share)		(0.02)	(0.22)	(0.29)	(0.51)
Diluted earnings per common share (in usd per share)		$ 2.10	$ 0.90	$ 1.48	$ 2.86
Stock options and share-based awards not included in diluted EPS calculation because their effect would have be antidilutive (in shares)		12	226	1	16

[1] Participating securities were included in the calculation of diluted earnings per share using the two-class method, as this calculation was more dilutive than the calculation using the treasury stock method.