Derivatives - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Derivative [Line Items]
Mark-to-Market Gain on Interest Rate Protection Agreements	$ 1,848	$ 0	$ 1,848	$ 0
2014 Swaps
Derivative [Line Items]
Debt Instrument, Term			7 years
Debt Instrument, Face Amount	$ 200,000		$ 200,000
Debt instrument, LIBOR Rate			one month LIBOR
Swaps, Number of Instruments Held	4		4
Swaps, Notional Amount	$ 200,000		$ 200,000
Swaps, Average Fixed Interest Rate	2.29%		2.29%
2015 Swaps
Derivative [Line Items]
Debt Instrument, Term			7 years
Debt Instrument, Face Amount	$ 260,000		$ 260,000
Debt instrument, LIBOR Rate			one month LIBOR
Swaps, Number of Instruments Held	6		6
Swaps, Notional Amount	$ 260,000		$ 260,000
Swaps, Average Fixed Interest Rate	1.79%		1.79%
Treasury Lock
Derivative [Line Items]
Debt instrument, LIBOR Rate			ten year U.S. Treasury
Swaps, Number of Instruments Held	2		2
Swaps, Notional Amount	$ 100,000		$ 100,000
Swaps, Average Fixed Interest Rate	2.18%		2.18%
Mark-to-Market Gain on Interest Rate Protection Agreements			$ 1,848