Employee Benefits and Stock Compensation - Summary of Stock Options Outstanding and Exercisable (Detail) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Options / SSARs Outstanding, Number of Shares Outstanding	102,000	87,000	107,000	109,000
Options / SSARs Outstanding, Weighted Average Remaining Contractual Life in Years	5 years 10 months 28 days
Options / SSARs Exercisable (Vested), Number of Shares Exercisable	53,000
Options / SSARs Exercisable (Vested), Weighted Average Exercise Price	$ 115.48
Options / SSARs Exercisable (Vested), Weighted Average Remaining Contractual Life in Years	2 years 6 months 29 days
Options / SSARs Exercisable (Vested), Aggregate Intrinsic Value	$ 0