Retirement Plans - Summary of ESOP Activities (Detail) - USD ($) $ in Thousands	3 Months Ended	6 Months Ended
Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
ESOP benefits expense	$ 464	$ 571	$ 905	$ 1,138
ESOP contributions made by the Company	$ 905	$ 571	$ 905	$ 1,506

This item represents the amount of cash contributions during the period made by the entity to the Employee Stock Ownership Plan (ESOP).

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 718
-SubTopic 40
-Section 50
-Paragraph 1
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=6418621&loc=d3e17540-113929

Name:	us-gaap_EmployeeStockOwnershipPlanESOPCashContributionsToESOP
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration