Derivative Financial Instruments - Summary of Interest Rate Swap Agreements (Detail) - Jun. 30, 2015 - USD ($)	Total
Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount	$ 125,000,000
Effective Date	Sep. 01, 2011
Expiration Date	Aug. 01, 2018
Fixed Rate Paid	2.37%
Interest Rate Swap [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap One [Member]
Derivative [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Dec. 30, 2011
Expiration Date	Dec. 29, 2017
Fixed Rate Paid	1.6125%
Interest Rate Swap One [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Two [Member]
Derivative [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Sep. 04, 2013
Expiration Date	Sep. 04, 2018
Fixed Rate Paid	1.371%
Interest Rate Swap Two [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Three [Member]
Derivative [Line Items]
Notional Amount	$ 100,000,000
Effective Date	Dec. 29, 2017
Expiration Date	Nov. 29, 2019
Fixed Rate Paid	3.968%
Interest Rate Swap Three [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR
Interest Rate Swap Four [Member]
Derivative [Line Items]
Notional Amount	$ 125,000,000
Effective Date	Aug. 01, 2018
Expiration Date	Jun. 01, 2020
Fixed Rate Paid	4.193%
Interest Rate Swap Four [Member] | London Interbank Offered Rate (LIBOR) [Member]
Derivative [Line Items]
Floating Rate Received	1 month LIBOR