Pension Plans and Other Postretirement Benefits - Financial Assets Accounted for at Fair Value on Recurring Basis (Detail) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Investments under executive deferred compensation plan	$ 22,168	[1]	$ 23,030	[1]
Private equity securities	1,806	[2]	771	[2]
Foreign currency forward contracts, assets	631	[3]	161	[3]
Obligations under executive deferred compensation plan	22,168	[1]	23,030	[1]
Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	607,694	[4]	616,545	[4]	563,303
Total Pension Benefits | Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	169,581	[5]	167,627	[5]
Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	85,007	[6]	70,609	[7]
Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	268,911	[8]	248,095	[9]
Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	80,740	[10]	125,137	[10]
Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,455		5,077
Total Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,439	[4]	5,620	[4]	6,611
Total Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,439	[8]	5,620	[9]
Quoted Prices in Active Markets for Identical Items (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Investments under executive deferred compensation plan	22,168	[1]	23,030	[1]
Private equity securities	21	[2]	21	[2]
Foreign currency forward contracts, assets	0		0
Obligations under executive deferred compensation plan	22,168	[1]	23,030	[1]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	513,871	[4]	482,002	[4]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	169,581	[5]	167,627	[5]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	85,007	[6]	70,609	[7]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	255,828	[8]	237,151	[9]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[10]	1,538	[10]
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,455		5,077
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Identical Items (Level 1) | Total Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[8]	0
Quoted Prices in Active Markets for Similar Items (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Investments under executive deferred compensation plan	0		0
Private equity securities	0		0
Foreign currency forward contracts, assets	631	[3]	161	[3]
Obligations under executive deferred compensation plan	0		0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,083	[4]	10,944	[4]
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[5]	0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[6]	0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,083	[8]	10,944	[9]
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[10]	0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		0
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,439	[4]	5,620	[4]
Quoted Prices in Active Markets for Similar Items (Level 2) | Total Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,439	[8]	5,620	[9]
Unobservable Inputs (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Investments under executive deferred compensation plan	0		0
Private equity securities	1,785	[2]	750
Foreign currency forward contracts, assets	0		0
Obligations under executive deferred compensation plan	0		0
Unobservable Inputs (Level 3) | Total Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	80,740	[4]	123,599	[4]	70,829
Unobservable Inputs (Level 3) | Total Pension Benefits | Domestic Equity Securities
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[5]	0
Unobservable Inputs (Level 3) | Total Pension Benefits | International Equity
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[6]	0
Unobservable Inputs (Level 3) | Total Pension Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	[8]	0
Unobservable Inputs (Level 3) | Total Pension Benefits | Absolute Return
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	80,740	[10]	123,599	[10]
Unobservable Inputs (Level 3) | Total Pension Benefits | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Unobservable Inputs (Level 3) | Total Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0		0
Unobservable Inputs (Level 3) | Total Postretirement Benefits | Fixed Income
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	[8]	$ 0

[1] We maintain an EDCP that was adopted in 2001 and subsequently amended. The purpose of the EDCP is to provide current tax planning opportunities as well as supplemental funds upon the retirement or death of certain of our employees. The EDCP is intended to aid in attracting and retaining employees of exceptional ability by providing them with these benefits. We also maintain a Benefit Protection Trust (the “Trust”) that was created to provide a source of funds to assist in meeting the obligations of the EDCP, subject to the claims of our creditors in the event of our insolvency. Assets of the Trust are consolidated in accordance with authoritative guidance. The assets of the Trust consist primarily of mutual fund investments (which are accounted for as trading securities and are marked-to-market on a monthly basis through the consolidated statements of income) and cash and cash equivalents. As such, these assets and obligations are classified within Level 1.

[2] Primarily consists of private equity securities classified as available-for-sale and are reported in Investments in the consolidated balance sheets. The changes in fair value are reported in Other (expenses) income, net, in our consolidated statements of income. Holdings in private equity securities are typically valued using the net asset valuations provided by the underlying private investment companies and as such are classified within Level 3.

[3] As a result of our global operating and financing activities, we are exposed to market risks from changes in foreign currency exchange rates, which may adversely affect our operating results and financial position. When deemed appropriate, we minimize our risks from foreign currency exchange rate fluctuations through the use of foreign currency forward contracts. Unless otherwise noted, these derivative financial instruments are not designated as hedging instruments under ASC 815, Derivatives and Hedging. The foreign currency forward contracts are valued using broker quotations or market transactions in either the listed or over-the-counter markets. As such, these derivative instruments are classified within Level 2.

[4] See Note 18 “Pension Plans and Other Postretirement Benefits” for further information about fair value measurements of our pension and postretirement plan assets, including the reconciliations of the plans’ Level 3 assets.

[5] Consists primarily of U.S. stock funds that track or are actively managed and measured against the S&P 500 index.

[6] Consists primarily of international equity funds which invest in common stocks and other securities whose value is based on an international equity index or an underlying equity security or basket of equity securities.

[7] Consists primarily of an international equity fund which invests in common stocks and other securities whose value is based on an international equity index or an underlying equity security or basket of equity securities.

[8] Consists primarily of debt obligations issued by governments, corporations, municipalities and other borrowers. Also includes insurance policies.

[9] Consists primarily of mutual funds that hold debt obligations issued by governments, corporations, municipalities and other borrowers. Also includes insurance policies.

[10] Consists primarily of funds with holdings in private investment companies. See additional information about the Absolute Return investments below.