CONDENSED CONSOLIDATED STATEMENTS OF EQUITY UNAUDITED - USD ($) $ in Thousands	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Accumulated Comprehensive Income [Member]	Treasury Stock [Member]	Total
Balance at Dec. 31, 2016	$ 33	$ 3,903	$ 80,515	$ 11,271	$ (262,369)	$ (166,647)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income	0	0	64,314	0	0	64,314
Net unrealized losses on securities available for sale, net of income tax benefit	0	0	0	2,830	0	2,830
Amounts reclassified from accumulated other comprehensive income, net of income tax expense	0	0	0	(1,811)	0	(1,811)
Foreign currency translation	0	0	0	75	0	75
Dividends declared	0	0	(1,803)	0	0	(1,803)
Stock based compensation expense	0	7,181	0	0	0	7,181
Purchase of treasury stock	0	0	0	0	(8,626)	(8,626)
Balance at Sep. 30, 2017	33	11,084	143,026	12,365	(270,995)	(104,487)
Balance at Dec. 31, 2016	33	3,903	80,515	11,271	(262,369)	(166,647)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Amounts reclassified from accumulated other comprehensive income, net of income tax expense						(12,100)
Balance at Dec. 31, 2017	33	12,572	155,939	11,876	(276,693)	(96,273)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Reclassification pursuant to adoption of ASU 2016-01, net of tax ($7,095) | ASU 2016-01 [Member]	0	0	12,110	(12,110)	0	0
Net income	0	0	93,859	0	0	93,859
Foreign currency translation	0	0	0	16	0	16
Dividends declared	0	0	(1,737)	0	0	(1,737)
Stock based compensation expense	0	1,042	0	0	0	1,042
Purchase of treasury stock	0	0	0	0	(9,097)	(9,097)
Balance at Sep. 30, 2018	$ 33	$ 13,614	$ 260,171	$ (218)	$ (285,790)	$ (12,190)