Derivative Financial Instruments - Interest Rate Derivatives Designated and Non Designated (Detail) (Interest Rate Caps [Member], USD $)	12 Months Ended
	Dec. 31, 2013
Cash Flow Hedging [Member] | Interest Rate Caps [Member] | 0.5% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2014-08
Strike Rate	0.50%
Notional Amount of Hedge	$ 13,408,000
Cost of Hedge	22,000
Estimated Fair Value of Cap in Other Comprehensive Income	(4,000)
Change in Cap Valuations Included in Other Comprehensive Income	(4,000)
Cash Flow Hedging [Member] | Interest Rate Caps [Member] | 0.69% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2016-10
Strike Rate	0.69%
Notional Amount of Hedge	150,000,000
Cost of Hedge
Estimated Fair Value of Cap in Other Comprehensive Income	(86,000)
Change in Cap Valuations Included in Other Comprehensive Income	(86,000)
Cash Flow Hedging [Member] | Interest Rate Caps [Member] | 4.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2017-11
Strike Rate	4.00%
Notional Amount of Hedge	50,000,000
Cost of Hedge	165,000
Estimated Fair Value of Cap in Other Comprehensive Income	186,000
Change in Cap Valuations Included in Other Comprehensive Income	21,000
Cash Flow Hedging [Member] | Interest Rate Caps [Member] | 5.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2018-11
Strike Rate	5.00%
Notional Amount of Hedge	50,000,000
Cost of Hedge	220,000
Estimated Fair Value of Cap in Other Comprehensive Income	248,000
Change in Cap Valuations Included in Other Comprehensive Income	28,000
Cash Flow Hedging [Member] | Interest Rate Caps [Member] | 0.5% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2016-05
Strike Rate	0.50%
Notional Amount of Hedge	42,440,000
Cost of Hedge
Estimated Fair Value of Cap in Other Comprehensive Income	(33,000)
Change in Cap Valuations Included in Other Comprehensive Income	(33,000)
Not Designated as Hedging Instrument [Member] | Interest Rate Caps [Member] | 1.00% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2014-10
Strike Rate	1.00%
Notional Amount of Hedge	5,753,000
Cost of Hedge	174,000
Estimated Fair Value of Cap in Other Comprehensive Income
Change in Cap Valuations Included in Interest Expense	1,000
Not Designated as Hedging Instrument [Member] | Interest Rate Caps [Member] | 1.25% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2013-05
Strike Rate	1.25%
Notional Amount of Hedge
Cost of Hedge	196,000
Estimated Fair Value of Cap in Other Comprehensive Income
Change in Cap Valuations Included in Interest Expense
Not Designated as Hedging Instrument [Member] | Interest Rate Caps [Member] | 1.75% Strike Rate Derivatives [Member]
Derivative [Line Items]
Derivative Maturity Period	2014-05
Strike Rate	1.75%
Notional Amount of Hedge	51,982,000
Cost of Hedge	434,000
Estimated Fair Value of Cap in Other Comprehensive Income
Change in Cap Valuations Included in Interest Expense