Financial Instruments - Summary of Outstanding Interest Rate Swap (Parenthetical) (Detail) (Interest Rate Swap [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Derivatives, Fair Value [Line Items]
Interest rate swap, description of interest received	Interest that varied with the three-month LIBOR
Interest rate swap, fixed interest rate	1.41%us-gaap_DerivativeFixedInterestRate	1.41%us-gaap_DerivativeFixedInterestRate
June 2015 [Member]
Derivatives, Fair Value [Line Items]
Notional value	$ 25,000	$ 25,000
Interest rate swap, expiration date	2015-06	2015-06

Nominal or face amount used to calculate payments on the derivative liability.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1B

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5580258-113959

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 1A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=35706170&loc=SL5579245-113959

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Notional Amount

-URI http://asc.fasb.org/extlink&oid=6519104

Name:	us-gaap_DerivativeLiabilityNotionalAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	instant