Employee Savings Plans - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Expenses related ESOP	$ 9,224,000	$ 7,380,000	$ 7,011,000
Shares vested under ESOP	4,142,000
Matching contributions to 401(k) retirement savings plan	10,651,000	9,318,000	8,456,000
Matching percentage of employer to employee contributions	100.00%
Temporary Equity, Shares Issued	57,821
Deferred compensation	8,421,000
Temporary Equity, Other Changes	4,358,000
Temporary Equity, Accretion to Redemption Value, Adjustment	4,063,000
Supplemental Executive Retirement Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assets for Plan Benefits, Noncurrent	$ 24,711,000	$ 15,872,000
Employee Stock Ownership Plan E S O P Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Maximum number of shares of common stock available for issuance	7,200,000