Fair Value of Financial Instruments - Summary Showing Sensitivity Analysis by Using Basis Point Variations (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013
+100 basis points
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Increase (Decrease) In Fair Value of Financial Instruments	$ (300)
- 100 basis points
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Estimated Increase (Decrease) In Fair Value of Financial Instruments	$ 300