Shareholders' Equity (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended				3 Months Ended								12 Months Ended
	Apr. 27, 2017	Apr. 25, 2017	Dec. 19, 2008	Jan. 31, 2019	Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2012	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Shareholders' Equity [Line Items]
Shares issued in public offering (in shares)					3,000,000
Proceeds from the issuance of common stock, net					$ 152,900											$ 0	$ 0	$ 152,911
Cash dividends declared per common share (in usd per share)								$ 0.19	$ 0.19	$ 0.19	$ 0.19	$ 0.14	$ 0.14	$ 0.14	$ 0.14	$ 0.76	$ 0.56	$ 0.48
Subsequent Event
Shareholders' Equity [Line Items]
Cash dividends declared per common share (in usd per share)				$ 0.25
Common stock dividends per share declared annualized (in usd per share)				$ 1
US Treasury
Shareholders' Equity [Line Items]
Warrants outstanding (in shares)			1,643,295
Warrant termination period			10 years
Warrants exercised (in shares)																22,952	318,491
Common stock, shares, issued from exercise of warrant shares (in shares)																16,571	219,372
Series C preferred stock
Shareholders' Equity [Line Items]
Shares issued (in shares)							126,500
Preferred stock, value, issued							$ 126,500
Preferred stock, dividend rate (as a percent)							5.00%
Preferred stock converted (in shares)	124,184	2,073																30
Convertible preferred stock, conversion rate	24.72
Series D preferred stock
Shareholders' Equity [Line Items]
Shares issued (in shares)						5,000,000		5,000,000				5,000,000				5,000,000	5,000,000
Preferred stock, value, issued						$ 125,000		$ 125,000				$ 125,000				$ 125,000	$ 125,000
Preferred stock, dividend rate (as a percent)						6.50%
London Interbank Offered Rate (LIBOR) | Series D preferred stock
Shareholders' Equity [Line Items]
Variable rate (as a percent)						4.06%
Common stock
Shareholders' Equity [Line Items]
Common stock issued in conversion (in shares)	3,069,828	51,244																729