Available-for-Sale Securities - Amortized Cost and Fair Value of Available-for-Sale Debt Securities by Contractual Maturity (Parenthetical) (Detail)	12 Months Ended
	Dec. 31, 2013
Minimum [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale security maturity period	5 years
Minimum [Member] | U. S. Government Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale security maturity period	5 years
Maximum [Member] | Corporate Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale security maturity period	10 years
Maximum [Member] | U. S. Government Agency Bonds [Member]
Schedule of Available-for-sale Securities [Line Items]
Available for sale security maturity period	10 years