CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2017	Dec. 31, 2016
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 1,682	$ 1,523
Accumulated depreciation (in dollars)	$ 109,667	$ 105,134
Stock Issued During Period, Shares, Convertible Preferred Shares	90,220,000
Common stock, shares issued	53,381,692	52,802,058
Series 4 Convertible Preferred Stock [Domain]
Stock Issued During Period, Shares, Convertible Preferred Shares	95,000
Convertible Preferred Stock [Member] | Series 4 Convertible Preferred Stock [Domain]
Preferred Stock, Liquidation Preference, Value	$ 95,507	$ 0
Stock Issued During Period, Shares, Convertible Preferred Shares	95,000	0
Shares, Outstanding	95,000	0
Common Stock [Member]
Shares, Outstanding	53,381,692	52,802,058
Common stock, shares outstanding	53,381,692	52,802,058
Common Stock [Member] | Common Class A
Shares, Outstanding	53,377,937	52,798,303
Common Stock [Member] | Common Class B
Shares, Outstanding	3,755	3,755
Share Capital To Be Issued [Member]
Shares to be issued, shares	0	100,000