Derivative Financial Instruments - Table of Derivative Financial Instruments (Details) (USD $) In Thousands, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Derivative
Fair value, liability	$ (4,127)	$ (5,053)
Fair value, asset	3,290	5,073
Interest Rate Swap | 1.23%
Derivative
Notional Amount	200,000	200,000
Index	LIBOR	LIBOR
Rate	1.23%	1.23%
Fair value, liability	(1,404)	(2,078)
Interest Rate Swap | 0.86%
Derivative
Notional Amount	100,000	100,000
Index	LIBOR	LIBOR
Rate	0.86%	0.86%
Fair value, liability	(465)	(729)
Interest Rate Swap | 1.39%
Derivative
Notional Amount	50,000	50,000
Index	LIBOR	LIBOR
Rate	1.39%	1.39%
Fair value, asset	812	1,350
Interest Rate Swap | 1.24%
Derivative
Notional Amount	105,000	105,000
Index	LIBOR	LIBOR
Rate	1.24%	1.24%
Fair value, asset	2,478	3,723
Interest Rate Swap | 4.98%
Derivative
Notional Amount	27,062	27,618
Index	LIBOR	LIBOR
Rate	4.98%	4.98%
Fair value, liability	$ (2,258)	$ (2,246)