Derivative Financial Instruments - Interest Rate Derivatives Designated and Non Designated (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2014
Cash Flow Hedging [Member] | Interest Rate Caps and Swaps [Member] | 0.5% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2014-08
Strike Rate	0.50%
Notional Amount of Hedge	$ 12,980
Cost of Hedge	22
Estimated Fair Value of Hedge	0
Change in Hedge Valuations Included in Other Comprehensive Income	6
Cash Flow Hedging [Member] | Interest Rate Caps and Swaps [Member] | 0.69% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2016-10
Strike Rate	0.69%
Notional Amount of Hedge	150,000
Cost of Hedge	0
Estimated Fair Value of Hedge	(419)
Change in Hedge Valuations Included in Other Comprehensive Income	(333)
Cash Flow Hedging [Member] | Interest Rate Caps and Swaps [Member] | 4.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2017-11
Strike Rate	4.00%
Notional Amount of Hedge	50,000
Cost of Hedge	165
Estimated Fair Value of Hedge	92
Change in Hedge Valuations Included in Other Comprehensive Income	(117)
Cash Flow Hedging [Member] | Interest Rate Caps and Swaps [Member] | 5.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2018-11
Strike Rate	5.00%
Notional Amount of Hedge	50,000
Cost of Hedge	220
Estimated Fair Value of Hedge	83
Change in Hedge Valuations Included in Other Comprehensive Income	(142)
Cash Flow Hedging [Member] | Interest Rate Caps And Swaps [Member] | 0.5% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2016-05
Strike Rate	0.50%
Notional Amount of Hedge	41,950
Cost of Hedge	0
Estimated Fair Value of Hedge	(83)
Change in Hedge Valuations Included in Other Comprehensive Income	(51)
Not Designated as Hedging Instrument [Member] | Interest Rate Caps and Swaps [Member] | 1.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2014-10
Strike Rate	1.00%
Notional Amount of Hedge	5,753
Cost of Hedge	174
Estimated Fair Value of Hedge	0
Change in Hedge Valuations Included in Interest Expense	0
Not Designated as Hedging Instrument [Member] | Interest Rate Caps and Swaps [Member] | 3.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2015-08
Strike Rate	3.00%
Notional Amount of Hedge	25,500
Cost of Hedge	10
Estimated Fair Value of Hedge	10
Change in Hedge Valuations Included in Interest Expense	$ 0