Acquisitions Acquisitions (Consideration Transferred) (Details) - USD ($) $ / shares in Units, $ in Thousands		12 Months Ended
	Dec. 01, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Number of SBS shares outstanding on the closing date of the Merger (in shares)		66,700,000	65,300,000
Total consideration transferred		$ 0	$ 453,390	$ 0
SBS [Member]
Business Acquisition [Line Items]
Number of SBS shares outstanding on the closing date of the Merger (in shares)	26,186,111
SBS common stock price per share on the closing date of the Merger (per share)	$ 16.99
Deemed (for accounting purposes only) issuance of BMC stock to SBS shareholders	$ 444,902
Fair value of SBS equity awards	8,488
Total consideration transferred	$ 453,390