Derivative Financial Instruments - Schedule of Derivatives (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Mar. 07, 2018	Dec. 31, 2017
Derivatives
Notional Amount	$ 350,000,000		$ 350,000,000			$ 401,079,000
Asset, Fair Value	2,860,000		2,860,000			1,525,000
Liability, Fair Value	(136,000)		(136,000)			(69,000)
Total change in fair value of interest rate derivatives	(11,000)	$ (81,000)	958,000	$ 213,000
Interest rate swaps
Derivatives
Notional Amount	100,000,000		100,000,000			56,079,000
Asset, Fair Value	431,000		431,000			10,000
Liability, Fair Value	(136,000)		(136,000)			(69,000)
Total change in fair value of interest rate derivatives	5,000	7,000	353,000	268,000
Interest rate caps
Derivatives
Notional Amount	250,000,000		250,000,000		$ 50,000,000.0	345,000,000
Asset, Fair Value	2,429,000		2,429,000			1,515,000
Liability, Fair Value	0		0			$ 0
Total change in fair value of interest rate derivatives	$ (16,000)	$ (88,000)	$ 605,000	$ (55,000)