Stock-Based Compensation (Detail) - Stock-Based Compensation Expense By Award Type (USD $)	3 Months Ended				9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 8,800,000	[1],[2]	$ 7,400,000	[1],[2]	$ 29,400,000	[1],[2]	$ 27,049,000	[1],[2]
Stock-based compensation expense reversal forfeited awards					1,900,000
Retirement eligible employees equity award
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	2,900,000		1,800,000		12,700,000		10,600,000
Stock appreciation rights (SARs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	1,000,000		1,100,000		3,900,000		4,100,000
Common stock equivalents (CSEs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	200,000		100,000		500,000		400,000
Restricted stock units (RSUs)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total stock-based compensation expense	$ 7,600,000		$ 6,200,000		$ 25,000,000		$ 22,500,000

[1] Includes charges of $2.9 million and $1.8 million for the three months ended September 30, 2014 and 2013, respectively, and $12.7 million and $10.6 million for the nine months ended September 30, 2014 and 2013, respectively, for awards to retirement-eligible employees since these awards vest on an accelerated basis.

[2] The nine months ended September 30, 2014 includes a reversal of $1.9 million of expense from forfeited awards related to the departure of the Company's former chief financial officer.