CONSOLIDATED STATEMENT OF CHANGES IN STOCKHOLDERS' EQUITY (Unaudited) - 9 months ended Sep. 30, 2017 - USD ($) $ in Thousands	Preferred Stock [Member]	Common Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Deficit [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Dec. 31, 2016	$ 0	$ 39	$ 341,270	$ (119,327)	$ (28,182)	$ (4,502)	$ 189,298
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Comprehensive income	0	0	0	55,232	0	4,502	59,734
Cumulative effect of a change in accounting principle - adoption of ASU 2016-09	0	0	74	6,464	0	0	6,538
Exercise of stock options	0	0	4,314	0	0	0	4,314
Tax effect of stock options and restricted stock units	0	0	(2,215)	0	0	0	(2,215)
Share-based employee compensation expense	0	0	5,019	0	0	0	5,019
Balance at Sep. 30, 2017	$ 0	$ 39	$ 348,462	$ (57,631)	$ (28,182)	$ 0	$ 262,688