Derivative Financial Instruments - Schedule of Derivatives (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jul. 16, 2018	Mar. 07, 2018	Dec. 31, 2017
Derivatives
Notional Amount	$ 452,930,000		$ 452,930,000				$ 401,079,000
Asset, Fair Value	3,341,000		3,341,000				1,525,000
Liability, Fair Value	(63,000)		(63,000)				(69,000)
Change in fair value of interest rate derivatives	298,000	$ 87,000	1,256,000	$ 300,000
Unrealized cash flow hedge losses	(130,000)	0	(130,000)	0
Total change in fair value of interest rate derivatives	168,000	87,000	1,126,000	300,000
Interest rate swaps
Derivatives
Total change in fair value of interest rate derivatives	319,000	124,000	673,000	392,000
Interest rate caps
Derivatives
Total change in fair value of interest rate derivatives	(151,000)	$ (37,000)	453,000	$ (92,000)
Not designated as accounting hedges
Derivatives
Notional Amount	400,000,000		400,000,000				401,079,000
Asset, Fair Value	3,341,000		3,341,000				1,525,000
Liability, Fair Value	0		0				(69,000)
Not designated as accounting hedges | Interest rate swaps
Derivatives
Notional Amount	100,000,000		100,000,000				56,079,000
Asset, Fair Value	744,000		744,000				10,000
Liability, Fair Value	0		0				(69,000)
Not designated as accounting hedges | Interest rate caps
Derivatives
Notional Amount	300,000,000		300,000,000		$ 50,000,000	$ 50,000,000.0	345,000,000
Asset, Fair Value	2,597,000		2,597,000				1,515,000
Liability, Fair Value	0		0				0
Designated as accounting hedge | Interest rate swaps
Derivatives
Notional Amount	52,930,000		52,930,000				0
Asset, Fair Value	0		0				0
Liability, Fair Value	$ (63,000)		$ (63,000)				$ 0