Stock Based Compensation - Additional Information (Detail) (USD $)	3 Months Ended	9 Months Ended																					4 Months Ended	9 Months Ended
	Oct. 06, 2012	Oct. 06, 2012	Oct. 06, 2012 Return On Invested Capital	Oct. 06, 2012 Return On Invested Capital Range One	Oct. 06, 2012 Return On Invested Capital Range Two	Oct. 06, 2012 Return On Invested Capital Range Three	Oct. 06, 2012 TSR Rank Less Than 50th Percentile Of S&P TSR	Oct. 06, 2012 TSR Rank Greater Than 50th Percentile Of S&P TSR	Oct. 06, 2012 Minimum	Oct. 06, 2012 Maximum	Oct. 06, 2012 Weighted Average Cost of Capital	Oct. 06, 2012 Weighted Average Cost of Capital Range One	Oct. 06, 2012 Weighted Average Cost of Capital Range Two	Oct. 06, 2012 Weighted Average Cost of Capital Range Three	Oct. 06, 2012 Total Shareholders Return	Oct. 06, 2012 Performance Contingent Restricted Stock	Oct. 06, 2012 Performance Contingent Restricted Stock TSR Rank Less Than 50th Percentile Of S&P TSR	Oct. 06, 2012 Stock Appreciation Rights	Oct. 06, 2012 Stock Appreciation Rights Minimum	Oct. 06, 2012 Stock Appreciation Rights Maximum	Oct. 06, 2012 Restricted Stock Awards	Oct. 06, 2012 Restricted Stock Awards TSR Rank Less Than 50th Percentile Of S&P TSR	Apr. 21, 2012 Deferred Stock	Oct. 06, 2012 Deferred Stock	Oct. 06, 2012 Deferred Stock Non Employee Directors	Oct. 06, 2012 Deferred Stock Minimum	Oct. 06, 2012 Deferred Stock Retainer Conversion	Oct. 06, 2012 Deferred Stock Annual Grant Awards	Oct. 06, 2012 Deferred Stock Activity	Oct. 06, 2012 Total Shareholders Return	Oct. 06, 2012 Performance Contingent Return On Invested Capital Shares	Oct. 06, 2012 Stock Option	Oct. 08, 2011 Nonqualified Stock Options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate number of shares that may be issued or transferred under EPIP	27,937,500	27,937,500
Share-based payment award, fair value assumptions, method used																														Inputs into the model included the following for the company and comparator companies: (i) total stockholder return from the beginning of the performance cycle through the measurement date; (ii) volatility; (iii) risk-free interest rates; and (iv) the correlation of the comparator companies’ total stockholder return. The inputs are based on historical capital market data.
Unrecognized compensation cost related to share based compensation															$ 2,700,000	$ 6,100,000													$ 900,000		$ 2,500,000	$ 2,700,000
Expected weighted-average period to recognize compensation cost (years)		1 year 3 months 18 days													1 year 3 months 18 days						1 year 1 month 6 days											1 year 2 months 12 days
Return on investment target over the two fiscal years immediately preceding the vesting date									1.75%	4.75%						3.75%
Percentage of shares that can be earned									0.00%	125.00%
Percentage of payout			0.00%								1.75%
Percentage of payout, ROIC above WACC				1.75%	3.75%	4.75%						50.00%	100.00%	125.00%
Grant date fair value award																$ 22.37													$ 20.62		$ 21.56
Percentage of ROI target	100.00%	100.00%
Exercise period (years)																2 years		1 year						1 year	1 year	2 years						2 years
Number of shares vested to plan participants																213	43,490	35,000											77,000
Maximum percentage of change in grant							20.00%	20.00%
Reduction in grant, percentage																						16.90%
Reduction in grant, common shares																						213,271
Percentage of change in grant							(1.30%)	1.30%
Maximum percentage of award, declared as dividends																100.00%
Dividends paid on vested performance-contingent restricted stock awards		255,000														200,000
Total fair value of shares vested																																	$ 3,400,000
Deferred shares exercised																											20,205	25,200	45,000
Aggregate shares converted																							18,330		47,800
Exercisable period																		9 years
Fair value of rights																			$ 6.99	$ 18.88
Dividend yield																		3.00%
Expected volatility																		29.00%
Risk-free interest																		0.23%
Expected life, maximum (years)																			18 days	1 year 10 months 6 days