Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 09, 2016	Jun. 30, 2016	Jun. 21, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current assets:
Trade accounts receivable, allowances for doubtful accounts	$ 6,291				$ 7,847	$ 2,485	$ 1,349
Other assets:
Patents, trademarks, and other intangible assets, accumulated amortization	$ 57,663				$ 44,695
Equity:
Common stock, par value (in dollars per share)	$ 0.01				$ 0.01
Common stock, shares authorized	150,000,000				100,000,000
Common stock, shares issued	117,851,063	22,300,000	11,500,000	11,500,000	83,013,971
Treasury stock, shares held	2,865,991				2,767,084	2,672,930	2,478,084