Consolidated Statements of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash dividends declared (in dollars per share)	$ 1.04	$ 0.96	$ 0.88
Retained Earnings
Cash dividends declared (in dollars per share)	$ 1.04	$ 0.96	$ 0.88