CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
Accounts receivable, allowance for doubtful accounts (in dollars)	$ 1,719	$ 1,306
Accumulated depreciation (in dollars)	$ 105,947	$ 96,554
Preferred stock, shares issued	0	0
Common Class A
Common stock, shares issued	50,349,056	49,986,705
Common stock, shares outstanding	50,349,056	49,986,705
Common Class B
Common stock, shares issued	3,755	3,755
Common stock, shares outstanding	3,755	3,755
Share Capital To Be Issued [Member]
Shares to be issued, shares	100,000
Share Capital To Be Issued [Member] | Common Class A
Shares to be issued, shares	100,000	0