Derivative Financial Instruments - Schedule of Derivatives (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Nov. 28, 2017	Sep. 18, 2017	Jun. 23, 2017	Feb. 07, 2017
Derivatives
Notional, Amount	$ 401,079,000	$ 326,901,000
Fair Value, Asset	1,525,000	259,000
Fair Value, Liability	(69,000)	(829,000)
Total change in fair value	1,127,000	(941,000)	$ (1,304,000)
Change in fair value of interest rate derivatives	1,127,000	(941,000)	(229,000)
Unrealized gain (loss) on cash flow hedge	0	0	(1,075,000)
Interest rate swaps
Derivatives
Notional, Amount	56,079,000	56,901,000
Fair Value, Asset	10,000	0
Fair Value, Liability	(69,000)	(829,000)
Total change in fair value	770,000	(795,000)	(1,071,000)
Interest rate caps
Derivatives
Notional, Amount	345,000,000	270,000,000		$ 50,000,000.0	$ 50,000,000.0	$ 50,000,000.0	$ 50,000,000
Fair Value, Asset	1,515,000	259,000
Fair Value, Liability	0	0
Total change in fair value	$ 357,000	$ (146,000)	$ (233,000)