Derivative Financial Instruments and Fair Value Measurements - Summary of SERP Assets Measured at Fair Value on Recurring Basis (Detail) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Money market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	$ 45	$ 4
Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	1,663	1,506
Level 1 | Money market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	0	0
Level 1 | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	0	0
Level 2 | Money market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	45	4
Level 2 | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	1,663	1,506
Level 3 | Money market
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	0	0
Level 3 | Mutual Funds
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
SERP assets measured at fair value on a recurring basis	$ 0	$ 0