Stockholders' Equity (Stock Transactions - Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands			3 Months Ended
	Apr. 30, 2019	Mar. 19, 2019	Mar. 31, 2019	Mar. 31, 2018	Apr. 26, 2019	Dec. 31, 2018
Class of Stock [Line Items]
Common stock, par value (dollars per share)			$ 0.01			$ 0.01
Proceeds from Issuance of Common Stock			$ 120,617	$ 236
Dividends declared per common share, during the period (in dollars per share)			$ 0.30	$ 0.30
At The Market Equity Offering Program
Class of Stock [Line Items]
Issuance of common stock (shares)			135,265
Proceeds from Issuance of Common Stock			$ 4,300
Subsequent Event
Class of Stock [Line Items]
Dividends declared per common share, during the period (in dollars per share)	$ 0.30
Subsequent Event | At The Market Equity Offering Program
Class of Stock [Line Items]
Number of authorized shares remaining under offering program (shares)					5,733,432
Equity Offering
Class of Stock [Line Items]
Issuance of common stock (shares)		3,737,500
Common stock, par value (dollars per share)		$ 0.01
Shares Issued, Price Per Share		$ 31.40
Proceeds from Issuance of Common Stock		$ 115,800
Minimum | At The Market Equity Offering Program
Class of Stock [Line Items]
Shares Issued During Period, Price Per Share			$ 32.01
Maximum | At The Market Equity Offering Program
Class of Stock [Line Items]
Shares Issued During Period, Price Per Share			32.86
Weighted Average | At The Market Equity Offering Program
Class of Stock [Line Items]
Shares Issued During Period, Price Per Share			$ 32.36