Dividends (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended					9 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Dividends Payable [Line Items]
Dividends, date declared		Jul. 28, 2015	May 05, 2015	Feb. 03, 2015
Dividends declared per common share (in usd per share)		$ 0.30	$ 0.30	$ 0.30	$ 0	$ 0.90	$ 0
Dividends, date of record		Aug. 28, 2015	Jun. 09, 2015	Mar. 03, 2015
Dividends, date paid		Sep. 15, 2015	Jun. 23, 2015	Mar. 18, 2015
Dividends paid		$ 5,139	$ 5,400	$ 5,600	$ 0	$ 16,158	$ 0
Paid to recipients of unvested restricted stock awards
Dividends Payable [Line Items]
Dividends paid		$ 200	$ 100	$ 200
Subsequent Event
Dividends Payable [Line Items]
Dividends, date declared	Oct. 27, 2015
Common Stock, Dividends, Per Share, Declared	$ 0.30
Dividends, date of record	Nov. 23, 2015
Dividends, date paid	Dec. 08, 2015