Consolidated Statement of Changes in Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Consolidated Statement of Changes in Stockholders' Equity [Abstract]
Purchase of treasury stock (in shares)	66,110	49,465	15,474
Cash dividends (in dollars per share)	$ 1.66	$ 1.71	$ 2.15
Dividend paid date	Jun. 30, 2016