Subsequent Events (Details) - USD ($)		9 Months Ended
	Oct. 13, 2017	Sep. 30, 2017	May 17, 2017	Dec. 31, 2016	Jan. 05, 2016	Jun. 10, 2015	May 19, 2015	Apr. 13, 2015
Second Term Loan [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity				$ 175,000,000				$ 100,000,000
Second Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 65,000,000
Third Term Loan [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity					$ 200,000,000	$ 125,000,000
Fourth Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity	110,000,000
Unsecured Debt [Member] | Revolving Credit Facility [Member] | Senior Unsecured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity		$ 450,000,000					$ 750,000,000
Unsecured Debt [Member] | Revolving Credit Facility [Member] | Senior Unsecured Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity	450,000,000
Unsecured Debt [Member] | Revolving Credit Facility [Member] | PHL Unsecured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity			$ 10,000,000
Unsecured Debt [Member] | Revolving Credit Facility [Member] | PHL Unsecured Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Maximum borrowing capacity	$ 10,000,000
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | First Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.40%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Second Term Loan [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.70%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Second Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.40%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Third Term Loan [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.45%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Third Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.40%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Fourth Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.70%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Debt [Member] | Revolving Credit Facility [Member] | Senior Unsecured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.55%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Debt [Member] | Revolving Credit Facility [Member] | Senior Unsecured Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.45%
Minimum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Debt [Member] | Revolving Credit Facility [Member] | PHL Unsecured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		1.55%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | First Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.20%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Second Term Loan [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.55%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Second Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.20%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Third Term Loan [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.20%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Third Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.20%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Fourth Term Loan [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.60%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Debt [Member] | Revolving Credit Facility [Member] | Senior Unsecured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.30%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Debt [Member] | Revolving Credit Facility [Member] | Senior Unsecured Revolving Credit Facility [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate	2.25%
Maximum [Member] | London Interbank Offered Rate (LIBOR) [Member] | Unsecured Debt [Member] | Revolving Credit Facility [Member] | PHL Unsecured Revolving Credit Facility [Member]
Subsequent Event [Line Items]
Debt Instrument, Basis Spread on Variable Rate		2.30%