CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Statement Of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 26,119	$ 22,329
Property, plant and equipment, accumulated depreciation	489,347	426,019
Intangible assets, accumulated amortization	$ 252,590	$ 151,025
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, authorized (in shares)	1,000,000	1,000,000
Preferred stock, issued (in shares)	737,000	770,000
Preferred stock, outstanding (in shares)	737,000	770,000
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized (in shares)	120,000,000	120,000,000
Common stock, issued (in shares)	85,060,835	84,852,584
Common stock, outstanding (in shares)	85,060,835	84,852,584