Derivative Financial Instruments - Summary of Effect of Derivative Financial Instruments on Consolidated Statements of Operations (Parenthetical) (Detail) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Total interest and related income	$ 155,400
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	109	$ (474)
Interest and related expenses	69,989	46,674
Interest Rate Swaps/Derivatives [Member] | Cash Flow Hedges [Member] | Interest Expense [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income		474,000
Interest Rate Swaps/Derivatives [Member] | Cash Flow Hedges [Member] | Interest Income [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Amount of Gain (Loss) Reclassified from Accumulated OCI into Income	109,000
Foreign Currency Contracts [Member] | Net Investment Hedges [Member]
Derivative Instruments and Hedging Activities Disclosures [Line Items]
Net cash settlements on our foreign currency forward contracts	7,400	7,400
Net cash settlements received	$ 1,800	$ 1,800