Derivative Financial Instruments - Summary of Outstanding Interest Rate Derivatives Designated as Cash Flow Hedges of Interest Rate Risk (Detail) - Cash Flow Hedges [Member] - Designated as Hedging Instrument [Member] € in Thousands, £ in Thousands, CAD in Thousands, $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2016 USD ($) DerivativeInstrument	Dec. 31, 2015 USD ($) DerivativeInstrument	Jun. 30, 2016 GBP (£) DerivativeInstrument	Jun. 30, 2016 EUR (€) DerivativeInstrument	Jun. 30, 2016 CAD DerivativeInstrument	Dec. 31, 2015 GBP (£) DerivativeInstrument	Dec. 31, 2015 EUR (€) DerivativeInstrument	Dec. 31, 2015 CAD DerivativeInstrument
Interest Rate Caps [Member] | USD [Member] | USD LIBOR [Member]
Derivative [Line Items]
Number of Instruments	26	26	26	26	26	26	26	26
Notional Amount | $	$ 1,097,632	$ 1,097,632
Strike	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%
Wtd. Avg. Maturity (Years)	9 months 18 days	9 months 18 days
Interest Rate Caps [Member] | CAD [Member] | CDOR [Member]
Derivative [Line Items]
Number of Instruments	6	7	6	6	6	7	7	7
Notional Amount | CAD					CAD 439,320			CAD 483,286
Strike	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%
Wtd. Avg. Maturity (Years)	9 months 18 days	1 year 2 months 12 days
Interest Rate Caps [Member] | EUR [Member] | EURIBOR [Member]
Derivative [Line Items]
Number of Instruments	1	1	1	1	1	1	1	1
Notional Amount | €				€ 15,142			€ 152,710
Strike	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%
Wtd. Avg. Maturity (Years)	9 months 18 days	1 year
Interest Rate Caps [Member] | GBP [Member] | GBP LIBOR [Member]
Derivative [Line Items]
Number of Instruments	1	1	1	1	1	1	1	1
Notional Amount | £			£ 15,142			£ 15,142
Strike	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%	2.00%
Wtd. Avg. Maturity (Years)	9 months 18 days	1 year 3 months 18 days
Interest Rate Swaps [Member] | CAD [Member] | CDOR [Member]
Derivative [Line Items]
Number of Instruments	2		2	2	2
Notional Amount | CAD					CAD 17,273
Wtd. Avg. Maturity (Years)	4 years 2 months 12 days