Stockholders' Equity (Details) - USD ($) $ / shares in Units, shares in Thousands		12 Months Ended
	Aug. 04, 2011	Dec. 31, 2010	Mar. 31, 2016	Dec. 31, 2015
Class of Stock [Line Items]
Liquidation preference per share			$ 1,000	$ 1,000
Securities purchase agreement, share repurchase amount	$ 11,879,000
Treasury's small business lending fund		$ 30,000,000,000
Treasury's small business lending fund, maximum asset value, qualified banks		$ 10,000,000,000
Noncumulative Preferred Stock [Member]
Class of Stock [Line Items]
Preferred stock shares issued and sold to the Treasury	13
Liquidation preference per share	$ 1,000
Aggregate proceeds from shares issued	$ 13,000,000
Principal amount paid related to CPP shares	11,750,000
Dividends paid related to CPP shares	$ 128,900