Business Combinations (Pro-Forma Information) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Revenue	$ 1,848,351	$ 1,765,391
Net income	140,468	$ 146,091
Pro Forma
Business Acquisition [Line Items]
One-time acquisition costs	1,800
Increase amortization expense	3,400
Increase in interest expense	7,600
Increase in depreciation expense	$ 4,500