Stockholders' Equity (Details) - USD ($) $ / shares in Units, $ in Thousands								1 Months Ended		9 Months Ended	12 Months Ended
	Sep. 19, 2019	Jun. 20, 2019	Mar. 21, 2019	Dec. 19, 2018	Sep. 17, 2018	Jun. 21, 2018	Mar. 22, 2018	May 31, 2019	Sep. 30, 2018	Sep. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 21, 2017	Apr. 30, 2017
Shareholders equity
Net proceeds from issuance of common stock											$ 52,714	$ 64,880	$ 0
Payments of stock issuance costs											$ 580	$ 195	$ 94
Shares authorized to be repurchased (in shares)											2,700,000			2,100,000
Dividends declared per Share of Common Stock (in dollars per share)	$ 0.31	$ 0.31	$ 0.31	$ 0.31	$ 0.31	$ 0.31	$ 0.31
Dividends paid per Share of Common Stock (in dollars per share)	$ 0.31	$ 0.31	$ 0.31	$ 0.31	$ 0.31	$ 0.31	$ 0.31
Common Stock
Shareholders equity
Treasury stock (in shares)										303,422
Treasury Stock
Shareholders equity
Treasury stock reissued (in shares)										303,422
Common Stock
Shareholders equity
Treasury stock reissued (in shares)												125,722
Treasury stock (in shares)													125,722
At The Market Offering
Shareholders equity
Equity distribution agreement, maximum value															$ 100,000
Sale of stock, number of shares issued in transaction (in shares)											299,497
Net proceeds from issuance of common stock											$ 3,000
Secondary Offering
Shareholders equity
Sale of stock, number of shares issued in transaction (in shares)								5,000,000	6,500,000	6,500,000
Treasury stock reissued (in shares)										303,422
Sale of stock, price per share (in dollars per share)								$ 10.14	$ 10.85	$ 10.85
Net proceeds from issuance of common stock								$ 49,300	$ 67,700
Payments of stock issuance costs								$ 1,400		$ 2,800