Contingencies - Additional Information (Detail) $ in Thousands	3 Months Ended
	Mar. 31, 2016 USD ($)
CalPERS [Member]
Loss Contingencies [Line Items]
Total compensatory damages value	$ 1,300,000
Unrealized losses claimed by the Plaintiff	$ 779,000
Abu Dhabi Commercial Bank [Member]
Loss Contingencies [Line Items]
Number of plaintiffs dismissed by court	4
Number of plaintiffs remaining	11
Number of plaintiffs filed motions for reconsideration	3
Number of plaintiffs granted	2
Number of additional plaintiffs dismissed by court	1
Number of plaintiffs ordered to trial	14
Number of plaintiffs filled notice of appeal	2
Abu Dhabi Commercial Bank [Member] | PSERS [Member]
Loss Contingencies [Line Items]
Total compensatory damages value	$ 5,750
Abu Dhabi Commercial Bank [Member] | Commerzbank AG [Member]
Loss Contingencies [Line Items]
Total compensatory damages value	$ 69,600