Fair Value Measurements - Additional Information (Detail) (USD $) In Thousands, unless otherwise specified			12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2013 Fair Value, Measurements, Nonrecurring [Member] Fair Value, Inputs, Level 2 [Member]
Fair Value Measurements Disclosure [Line Items]
Recognized impairment			$ 275,133
Securities held to maturity, fair value	$ 536,583	$ 583,287	$ 486,299