Consolidated Statements of Changes in Partners' Equity (Parenthetical) (Parentheticals) - $ / shares	3 Months Ended				12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Statement of Stockholders' Equity [Abstract]
Cash distributions declared per common unit	$ 0.3825	$ 0.3650	$ 0.3475	$ 0.3325	$ 1.4275	$ 1.1632	$ 0