Significant Accounting Policies, Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance				$ 200,790
Ending balance		$ 111,213		111,213
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance		(16,115)	$ 47,114	(13,565)	$ 39,747
Ending balance		(26,853)	18,411	(26,853)	18,411
Unrealized Losses on Securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Other comprehensive loss before reclassifications, net of tax	[1]	(10,738)	(28,703)	(13,288)	(21,336)
Net current period other comprehensive loss		(10,738)	(28,703)	(13,288)	(21,336)
Income tax benefit included in other comprehensive income		$ 0	$ 5,100	$ 0	$ 0

[1] Other comprehensive income (loss) for the three months ended June 30, 2015 included income tax benefit of $5.1 million. There was no tax expense or benefit for the three and six months ended June 30, 2016 and the six months ended June 30, 2015.