Statement of Consolidated Stockholders' Equity (USD $) In Millions, except Share data, unless otherwise specified	Total	Common Stock	Additional Paid in Capital	Retained Earnings	Common Stock Owned by Union VEBA		Treasury Stock	Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2009	$ 870.3	$ 0.2	$ 967.8	$ 85.0	$ (116.4)		$ (28.1)	$ (38.2)
Beginning balance, shares at Dec. 31, 2009		20,276,571
Stockholders' Equity [Roll Forward]
Net income	12.0			12.0
Other comprehensive income, net of tax	18.5							18.5
Release of restriction on Union VEBA shares, net of tax of $19.6, $25.0, and $41.3 for 2010, 2011, and 2012, respectively)	32.5		0.7		31.8	[1]
Issuance of warrants	14.3		14.3
Issuance of non-vested shares to employees		97,931
Issuance of common shares to directors, shares		4,612
Issuance of common shares to directors	0.2		0.2
Issuance of common shares to employees upon vesting of restricted stock units and performance shares		4,934
Cancellation of employee non-vested shares		(5,968)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares		(11,729)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(0.4)		(0.4)
Repurchase of common stock, shares		1,151,900
Repurchase of common stock	44.2						44.2
Cash dividends on common stock ($0.96, $0.96 and $1.00 per share for 2010, 2011, and 2012, respectively)	(19.0)			(19.0)
Amortization of unearned equity compensation	4.5		4.5
Ending balance at Dec. 31, 2010	888.7	0.2	987.1	78.0	(84.6)		(72.3)	(19.7)
Ending balance, shares at Dec. 31, 2010		19,214,451
Stockholders' Equity [Roll Forward]
Net income	25.1			25.1
Other comprehensive income, net of tax	(65.3)							(65.3)
Release of restriction on Union VEBA shares, net of tax of $19.6, $25.0, and $41.3 for 2010, 2011, and 2012, respectively)	40.5		8.8		31.7	[1]
Issuance of non-vested shares to employees		83,066
Issuance of common shares to directors, shares		3,750
Issuance of common shares to directors	0.2		0.2
Issuance of common shares to employees upon vesting of restricted stock units and performance shares		17,444
Cancellation of employee non-vested shares		(2,889)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares		(62,637)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	(3.1)		(3.1)
Cash dividends on common stock ($0.96, $0.96 and $1.00 per share for 2010, 2011, and 2012, respectively)	(18.9)			(18.9)
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	0.2		0.2
Amortization of unearned equity compensation	5.2		5.2
Reclassification relating to dividends on unvested equity awards	0.2			0.2
Ending balance at Dec. 31, 2011	872.8	0.2	998.4	84.4	(52.9)		(72.3)	(85.0)
Ending balance, shares at Dec. 31, 2011	19,253,185	19,253,185
Stockholders' Equity [Roll Forward]
Net income	85.8			85.8
Other comprehensive income, net of tax	59.0							59.0
Release of restriction on Union VEBA shares, net of tax of $19.6, $25.0, and $41.3 for 2010, 2011, and 2012, respectively)	67.3		14.4		52.9	[1]
Issuance of non-vested shares to employees		92,949
Issuance of common shares to directors, shares		3,930
Issuance of common shares to directors	0.2		0.2
Issuance of common shares to employees upon vesting of restricted stock units and performance shares		11,327
Cancellation of employee non-vested shares		(2,355)
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares, shares		45,801
Cancellation of shares to cover employees’ tax withholdings upon vesting of non-vested shares	2.2		2.2
Cash dividends on common stock ($0.96, $0.96 and $1.00 per share for 2010, 2011, and 2012, respectively)	(19.6)			(19.6)
Excess tax benefit upon vesting of non-vested shares and dividend payment on unvested shares expected to vest	1.3		1.3
Amortization of unearned equity compensation	5.6		5.6
Reclassification relating to dividends on unvested equity awards	0.6			0.6
Ending balance at Dec. 31, 2012	$ 1,070.8	$ 0.2	$ 1,017.7	$ 151.2	$ 0		$ (72.3)	$ (26.0)
Ending balance, shares at Dec. 31, 2012	19,313,235	19,313,235

[1] At $24.02 per share reorganization value.