Shareholders' Equity (Summary of the Company's Common and Preferred Stock) (Details) - $ / shares	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Common Stock:
Shares authorized	100,000,000	100,000,000
Shares issued	56,068,220	51,978,289
Preferred Stock:
Shares authorized	20,000,000	20,000,000
Common stock
Common Stock:
Shares authorized	100,000,000	100,000,000
Shares issued	56,068,220	51,978,289
Shares outstanding	55,965,207	51,880,540
Cash dividend per share	$ 0.56	$ 0.48
Preferred stock
Preferred Stock:
Shares authorized	20,000,000	20,000,000
Shares issued	5,000,000	5,126,257
Shares outstanding	5,000,000	5,126,257