Securities - Additional Information (Detail) $ in Thousands	Mar. 31, 2016 USD ($) Securities	Dec. 31, 2015 USD ($) Securities
Investments, Debt and Equity Securities [Abstract]
Number of securities holdings \| Securities	0	0
Shareholders' equity percentage	10.00%	10.00%
Securities \| $	$ 315,987	$ 312,669

The fair value of trading securities that serve as collateral for borrowings.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5086-111524

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