Fair Value Measurement - Fair Value Option for Newly Originated Permanent Construction Loans Held for Sale (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Fair Value Inputs Assets Quantitative Information [Line Items]
Aggregate fair value	$ 59,967	$ 26,716
Construction [Member]
Fair Value Inputs Assets Quantitative Information [Line Items]
Aggregate fair value	59,967	26,716
Contractual balance	56,242	25,197
Gain (loss)	$ 3,725	$ 1,519

For loans held as assets for which the fair value option has been elected, this item represents the difference between the aggregate fair value and the aggregate unpaid principal balance of those loans that are 90 days or more past due, in nonaccrual status, or both.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
-SubTopic 10
-Section 50
-Paragraph 28
-Subparagraph (e)(3)
-URI http://asc.fasb.org/extlink&oid=6957238&loc=d3e14064-108612

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