Stock Repurchase Program (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Feb. 29, 2016	Jan. 31, 2014
Class of Stock [Line Items]
Number of shares authorized to be repurchased (up to) (in shares)				1,000,000	500,000
Remaining number of shares authorized to be repurchased (in shares)	810,000	56,000
Treasury Stock
Class of Stock [Line Items]
Shares repurchase and retired during period (in shares)	246,000	212,000	261,000
Stock repurchased during period, value	$ 2.0	$ 1.7	$ 5.9