Financing Activity - Applicable Credit Spread Over Libor at Various Leverage Levels (Detail)	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015
2015 Five Year Term Loan [Member] | Minimum [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Capitalization Rates	6.50%
2015 Five Year Term Loan [Member] | Maximum [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Capitalization Rates	7.50%
Two Thousand Fourteen Term Loans [Member] | Minimum [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Capitalization Rates	6.50%
Two Thousand Fourteen Term Loans [Member] | Maximum [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Capitalization Rates	7.50%
2013 Revolving Credit Facility [Member] | Minimum [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Capitalization Rates		6.50%
2013 Revolving Credit Facility [Member] | Maximum [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Capitalization Rates		7.50%
Ratio One [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2015 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.35%
Ratio One [Member] | London Interbank Offered Rate (LIBOR) [Member] | Seven Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.80%
Ratio One [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2014 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.35%
Ratio One [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2013 Revolving Credit Facility [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate		1.20%
Ratio Two [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2015 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.45%
Ratio Two [Member] | London Interbank Offered Rate (LIBOR) [Member] | Seven Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.95%
Ratio Two [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2014 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.45%
Ratio Two [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2013 Revolving Credit Facility [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate		1.25%
Ratio Three [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2015 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.60%
Ratio Three [Member] | London Interbank Offered Rate (LIBOR) [Member] | Seven Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	2.15%
Ratio Three [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2014 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.60%
Ratio Three [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2013 Revolving Credit Facility [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.60%	1.30%
Ratio Four [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2015 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.90%
Ratio Four [Member] | London Interbank Offered Rate (LIBOR) [Member] | Seven Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	2.35%
Ratio Four [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2014 Five Year Term Loan [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate	1.90%
Ratio Four [Member] | London Interbank Offered Rate (LIBOR) [Member] | 2013 Revolving Credit Facility [Member]
Schedule Of Maximum Leverage Ratio [Line Items]
Stated Interest Rate		1.55%