Quarterly report pursuant to Section 13 or 15(d)

Shareholders' Equity - Narrative (Details)

Shareholders' Equity - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		6 Months Ended		136 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Mar. 31, 2007
Capital Unit [Line Items]
Shares authorized for repurchase (in shares) (up to)						27,500,000
Repurchase and retirement of common stock (in shares)	472,215		757,615		20,107,830
Repurchase and retirement of common stock			$ 3,428		$ 51,778
Shares repurchased, value	$ 1,637		$ 2,569
Shares available for purchase (in shares)	7,392,170		7,392,170		7,392,170
Non-cash compensation expense	$ 1,568	$ 1,378	$ 3,062	$ 2,807
Shares surrendered for tax withholdings (in shares)			247,379
Preferred stock dividends declared and paid	8,508		$ 17,016
Common stock dividends declared and paid	$ 1,969		$ 3,929
Series A Preferred Stock
Capital Unit [Line Items]
Dividends paid per share on monthly basis (in USD per share)			$ 0.1667
Common Stock
Capital Unit [Line Items]
Common stock cash dividend (in dollars per share)	$ 0.01		$ 0.01
Employees
Capital Unit [Line Items]
Stock-based compensation			$ 3,035
Consultants and Independent Financial Advisors
Capital Unit [Line Items]
Stock-based compensation	$ 20		27
Options
Capital Unit [Line Items]
Unrecognized compensation cost for stock based compensation	$ 829		$ 829		$ 829
Unrecognized compensation cost for stock based compensation, period of recognition			1 year
Purchase of shares (in shares)	1,025,543		1,710,212
Intrinsic value of options exercised	$ 1,914		$ 2,935
Restricted shares
Capital Unit [Line Items]
Unrecognized compensation cost for stock based compensation	10,347		$ 10,347		10,347
Unrecognized compensation cost for stock based compensation, period of recognition			2 years 7 months 65 days
Restricted shares \| Employees
Capital Unit [Line Items]
Non-cash compensation expense	1,548		$ 3,035
Restricted shares \| Awards Granted In 2018
Capital Unit [Line Items]
Unrecognized compensation cost for stock based compensation	$ 6,092		$ 6,092		$ 6,092
Unrecognized compensation cost for stock based compensation, period of recognition			3 years 3 months 28 days
Options, Warrants, and Other
Capital Unit [Line Items]
Shares surrendered for tax withholdings (in shares)	89,438		469,805
Additional Paid-In Capital
Capital Unit [Line Items]
Repurchase and retirement of common stock			$ 3,428
Preferred stock dividends declared and paid			17,016
Common stock dividends declared and paid			3,929
Additional Paid-In Capital \| Employees
Capital Unit [Line Items]
Stock-based compensation			$ 3,035