Derivative Instruments and Hedging Activities - Fair Value of Company's Derivative Financial Instruments Classification in Unaudited Condensed Consolidated Balance Sheets (Detail) - USD ($) $ in Thousands	Mar. 31, 2018	Dec. 31, 2017
Derivatives Fair Value [Line Items]
Asset Derivatives Fair Value	$ 1,810
Liability Derivatives Fair Value		$ 8,455
Other Liabilities [Member]
Derivatives Fair Value [Line Items]
Asset Derivatives Fair Value	1,810
Liability Derivatives Fair Value		8,455
Interest Rate Swaps [Member] | Other Assets [Member]
Derivatives Fair Value [Line Items]
Asset Derivatives Fair Value	$ 1,810
Interest Rate Swaps [Member] | Other Liabilities [Member]
Derivatives Fair Value [Line Items]
Liability Derivatives Fair Value		$ 8,455