Note Securities purchased under agreements to resell (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Disclosure Securities Purchases Under Agreements To Resell
Repledged	$ 0	$ 145,866
Not repledged	111,545	33,258
Total	$ 111,545	$ 179,124

Fair value of the collateral, or portion thereof, that has been re-pledged, delivered, or otherwise used.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 30
-Section 50
-Paragraph 1A
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=34720971&loc=SL6224234-111729

Name:	us-gaap_FairValueOfSecuritiesReceivedAsCollateralThatHaveBeenResoldOrRepledged
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant