Stockholders' Equity (Additional Information) (Detail) (USD $)	12 Months Ended		6 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Jul. 01, 2011	Dec. 31, 2012	May 01, 2004	Sep. 30, 2013
Stockholders Equity Note [Line Items]
Common stock shares authorized	50,000,000	50,000,000
Common stock, par value	$ 1	$ 1
Repurchase Of Common Stock Shares	38,032
Additional dividend payable	$ 72,600,000
Long term borrowings	35,000,000	0		0
Stock repurchased during period, shares	0	0
Director Plan
Stockholders Equity Note [Line Items]
Shares authorized but unissued					45,000
Shares available for issuance	26,386
Purchase Plan
Stockholders Equity Note [Line Items]
Shares authorized but unissued			300,000
Shares available for issuance	203,523
Share exercise price description			Shares are purchased at 85% of the fair market value on the exercise date through monthly payroll deductions of not less than 1% or more than 10% of cash compensation paid in the month
Current Program
Stockholders Equity Note [Line Items]
Repurchase of outstanding shares of common stock						5.00%
Repurchase of outstanding shares of common stock under Stock Repurchase Program						1,260,000
Repurchase Program
Stockholders Equity Note [Line Items]
Repurchase of outstanding shares of common stock						3.00%
Repurchase of outstanding shares of common stock under Stock Repurchase Program						730,000
Repurchase Of Common Stock Shares	38,032
Stock Repurchase Program Authorized Amount	$ 900,000