Consolidated Statements of Changes in Stockholders' Equity (Parentheticals) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Shares of common stock allocated by ESOP, including excess income tax benefits		58,618	181,181
Shares of common stock issued under compensation plans, including excess income tax benefits	944,504	1,567,607	3,294,995
Shares of common stock issued upon extinguishment of convertible senior notes		3,959,396	5,489,808
Shares of common stock issued to settle warrants that have reached their expiration	47,868
Dividends on common stock, per share amount	$ 0.22	$ 0.20	$ 0.18