Interest Rate Contracts - Summary of Interest Rate Swap Agreements (Detail) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Interest rate swap asset	$ 5,594	$ 0
Interest rate swap liability	2,045	3,144
Interest Rate Swap 1
Derivative [Line Items]
Interest rate swap liability	$ 778
Interest Rate Swap 1 | Derivative Financial Instruments, Assets
Derivative [Line Items]
Interest Strike Rate	1.349%
Interest rate swap asset	$ 3,245	0
Derivative Asset, Notional Amount	$ 0	0
Interest Rate Swap 2 | Derivative Financial Instruments, Assets
Derivative [Line Items]
Interest Strike Rate	1.406%
Interest rate swap asset	$ 2,349	0
Derivative Asset, Notional Amount	$ 0	0
Interest Rate Swap 3 | Derivative Financial Instruments, Liabilities
Derivative [Line Items]
Interest Strike Rate	1.826%
Interest rate swap liability	$ 338	538
Derivative Liability, Notional Amount	30,000	30,000
Interest Rate Swap 4
Derivative [Line Items]
Interest rate swap asset	$ 4,327
Interest Rate Swap 4 | Derivative Financial Instruments, Liabilities
Derivative [Line Items]
Interest Strike Rate	2.01%
Interest rate swap liability	$ 440	698
Derivative Liability, Notional Amount	$ 29,674	30,000
Interest Rate Swap 5 | Derivative Financial Instruments, Liabilities
Derivative [Line Items]
Interest Strike Rate	1.79%
Interest rate swap liability	$ 529	849
Derivative Liability, Notional Amount	$ 50,000	50,000
Interest Rate Swap 6 | Derivative Financial Instruments, Liabilities
Derivative [Line Items]
Interest Strike Rate	2.005%
Interest rate swap liability	$ 738	1,059
Derivative Liability, Notional Amount	$ 50,000	$ 0