Common Stock and Dividends (Details) - USD ($)					9 Months Ended
	Oct. 17, 2016	Aug. 02, 2016	Apr. 18, 2016	Apr. 09, 2016	Sep. 30, 2016	Nov. 03, 2016
Common Stock and Dividends
Series A cumulative perpetual preferred shares, outstanding					216,000
Warrants to purchase entity's common stock (in shares)					1,326,238
Warrants, exercise price (in dollars per share)					$ 24.43
Percentage of aggregate common stock investment on exercise of warrant to Senior Preferred Stock investment					15.00%
Warrants, term					10 years
Cash dividends (as a percent)					0.33%
Cash dividends paid to common shareholders (in dollars per share)	$ 0.31		$ 0.29
Repurchase of common stock, authorized amount				$ 40,000,000	$ 40,000,000
Period of repurchase of common stock				12 months
Cumulative number of shares repurchased under all stock repurchase programs						9,240,629
Cumulative cost of shares repurchased under all stock repurchase programs		$ 271,096,000