Equity - Additional Information (Detail) (USD $)	1 Months Ended			12 Months Ended
	Sep. 30, 2012	Feb. 28, 2011	Mar. 31, 2010	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Equity [Line Items]
Common stock issued in connection with business acquisitions	60,855	372,992
Number of common shares issued to qualified pension plan			1,190,000
Common stock, par value			$ 1	$ 1	$ 1	$ 1
Increase in equity from issuance of common shares to pension plan			$ 53,864,000
Value of common shares issued to pension plan			1,190,000
Increase in capital in excess of par from issuance of common shares to pension plan			52,674,000
Shares of common stock issued to trustee under 401(k) savings and retirement plan					110,881	882,131
Net proceeds from issuance of common stock to the trustee under 401(k) savings and retirement plan					4,745,000	41,734,000
Reclassification of stock				$ 10,764,000
Number of shares held in treasury				0	0	0
Number of treasury shares purchased				0	0	0
Shares remaining under the current authorization repurchase program				3,411,416