STOCK-BASED COMPENSATION (Tables)

12 Months Ended

Dec. 31, 2015

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Stock-based compensation expense

Stock-based compensation expense was as follows:

	Years ended December 31,
	2015			2014			2013
	($ in millions)
Stock-based compensation	$	11.5		$	9.2		$	13.3
Mark-to-market adjustments	(3.0		)	(3.6		)	4.2
Total expense	$	8.5		$	5.6		$	17.5

Stock Options Activity

Stock option transactions were as follows:

						Exercisable
	Shares		Option Price	Weighted-Average Option Price		Options	Weighted-Average Exercise Price
Outstanding at January 1, 2015	4,133,753		$14.28-27.64	$	20.14	2,976,870	$	18.50
Granted	776,750		27.40	27.40
Exercised	(147,608	)	14.28-25.57	20.11
Canceled	(42,790	)	23.28-27.40	25.14
Outstanding at December 31, 2015	4,720,105		$14.28-27.65	$	21.29	3,371,449	$	19.28

Stock Options Exercisable, Exercise Price Range

The following table provides certain information with respect to stock options exercisable at December 31, 2015:

Range of Exercise Prices	Options Exercisable	Weighted-Average Exercise Price		Options Outstanding	Weighted-Average Exercise Price
Under $16.00	916,046	$	15.05	916,046	$	15.05
$16.00 – $22.00	1,870,281	19.85		1,870,281	19.85
Over $22.00	585,122	24.11		1,933,778	25.65
	3,371,449			4,720,105

Common shares reserved and available for grant or purchase

At December 31, 2015, common shares reserved for issuance and available for grant or purchase under the following plans consisted of:

	Number of Shares
Stock Option Plans	Reserved for Issuance	Available for Grant or Purchase(1)
2000 long term incentive plan	277,586	2,911
2003 long term incentive plan	389,921	10,138
2006 long term incentive plan	1,591,479	168,783
2009 long term incentive plan	2,762,161	506,610
2014 long term incentive plan	3,000,000	2,009,000
Total under stock option plans	8,021,147	2,697,442

	Number of Shares
Stock Purchase Plans	Reserved for Issuance	Available for Grant or Purchase
1997 stock plan for non-employee directors	572,978	567,476
Employee deferral plan	45,627	45,623
Total under stock purchase plans	618,605	613,099

(1) All available to be issued as stock options, but includes a sub-limit for all types of stock awards of 1,420,442 shares.

Performance Shares Transactions

Performance share transactions were as follows:

	To Settle in Cash				To Settle in Shares
	Shares		Weighted-Average Fair Value per Share		Shares		Weighted-Average Fair Value per Share
Outstanding at January 1, 2015	290,917		$	23.04	281,000		$	23.46
Granted	126,000		27.40		126,000		27.40
Paid/Issued	(105,611	)	23.04		(101,000	)	21.92
Converted from shares to cash	2,111		24.42		(2,111	)	24.42
Canceled	(1,889	)	25.83		(1,889	)	26.49
Outstanding at December 31, 2015	311,528		$	17.48	302,000		$	25.59
Total vested at December 31, 2015	201,528		$	17.48	192,000		$	24.81

Summary of Unvested Performance Shares

The summary of the status of our unvested performance shares to be settled in cash were as follows:

	Shares		Weighted-Average Fair Value per Share
Unvested at January 1, 2015	87,334		$	23.04
Granted	126,000		27.40
Vested	(101,445	)	17.48
Canceled	(1,889	)	25.83
Unvested at December 31, 2015	110,000		$	17.48