Condensed Consolidated Statement Of Stockholders' Equity (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Statement of Stockholders' Equity [Abstract]
Issuance of common stock (in shares)	395,274	505,312	476,047
Issuance of deferred stock units (in shares)	4,784	36,578	43,188
Special cash dividend, per share	$ 1.4	$ 2