Investment in Securities, Reclassifications Out of Accumulated Other Comprehensive Income ("AOCI") into Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Amount Reclassified from AOCI [Abstract]
Net gain from investments - Realized gain / (loss) on sale of securities	$ 0	$ 348	$ 30	$ 3,511
Other operating expenses	45	0	80	3,639
Other Comprehensive Income (Loss), Reclassification Adjustment for Write-down of Securities Included in Net Income, before Tax	(150)	0	(150)	(69)
Income before income taxes	(105)	348	(40)	7,081
Income tax provision	39	(129)	15	(2,620)
Net income	$ (66)	$ 219	$ (25)	$ 4,461
Shares under derivative contract (in shares)	170,000	2,300,000	170,000	2,300,000	3,800,000