CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Total	Common Class A [Member]	Common Class B [Member]	Additional Paid In Capital [Member]	Retained Earnings [Member]
Opening Balance SHARES at Dec. 31, 2012		31,226,047	7,197,532
Conversion of Class B common stock to Class A common stock SHARES		0	0
Compensation expense related to granting of restricted stock awards SHARES		96,560	0
Issuance of common stock related to an incentive plan SHARES		0	0
Common stock repurchase SHARES		0	0
Exercise of stock options SHARES		171,625	0
Purchase of vested employee restricted stock units SHARES	(186,000)	(186,038)	0
Ending Balance SHARES at Dec. 31, 2013		31,308,194	7,197,532
Opening Balance VALUE at Dec. 31, 2012	$ 269,494	$ 312	$ 72	$ 601,847	$ (332,737)
Net income (loss)	26,024				26,024
Compensation expense related to granting of restricted stock awards VALUE	4,270	1	0	4,269	0
Issuance of common stock related to an incentive plan VALUE	0	0	0	0	0
Common stock repurchase VALUE	0	0	0	0	0
Purchase of vested employee restricted stock units	(1,640)	(2)	0	(1,638)	0
Forfeitures of dividend equivalents VALUE	0	0	0	0	0
Realization of tax benefit for dividend equivalent payments VALUE	0	0	0	0	0
Exercise of stock options VALUE	245	2	0	243	0
Preferred stock dividend	0
Net unrealized gain (loss) on investments VALUE		0
Net unrealized gain (loss) on derivatives VALUE	0		0	0	0
Ending Balance VALUE at Dec. 31, 2013	$ 298,393	$ 313	$ 72	604,721	(306,713)
Conversion of Class B common stock to Class A common stock SHARES		0	0
Compensation expense related to granting of restricted stock awards SHARES		638,102	0
Issuance of common stock related to an incentive plan SHARES		0	0
Common stock repurchase SHARES		0	0
Exercise of stock options SHARES		57,500	0
Purchase of vested employee restricted stock units SHARES	(142,000)	(141,502)	0
Ending Balance SHARES at Dec. 31, 2014		31,862,294	7,197,532
Net income (loss)	$ 26,823				26,823
Compensation expense related to granting of restricted stock awards VALUE	5,232	$ 7	$ 0	5,225	0
Issuance of common stock related to an incentive plan VALUE	0	0	0	0	0
Common stock repurchase VALUE	0	0	0	0	0
Purchase of vested employee restricted stock units	(1,514)	(1)	0	(1,513)	0
Forfeitures of dividend equivalents VALUE	5	0	0	0	5
Realization of tax benefit for dividend equivalent payments VALUE	0	0	0	0	0
Exercise of stock options VALUE	82	0	0	82	0
Preferred stock dividend	0
Net unrealized gain (loss) on derivatives VALUE		0	0	0	0
Ending Balance VALUE at Dec. 31, 2014	$ 329,021	$ 319	$ 72	608,515	(279,885)
Conversion of Class B common stock to Class A common stock SHARES		0	0
Compensation expense related to granting of stock options SHARES	0
Compensation expense related to granting of restricted stock awards SHARES		738,195	0
Issuance of common stock related to an incentive plan SHARES		0	0
Exercise of stock options SHARES	11,750	11,750	0
Purchase of vested employee restricted stock units SHARES	(132,000)	(131,688)	0
Ending Balance SHARES at Dec. 31, 2015		32,480,551	7,197,532
Net income (loss)	$ 29,184				29,184
Compensation expense related to granting of restricted stock awards VALUE	5,524	$ 7	$ 0	5,517	0
Issuance of common stock related to an incentive plan VALUE	0	0	0	0	0
Common stock repurchase VALUE	0	0	0	0	0
Purchase of vested employee restricted stock units	(1,562)	(1)	0	(1,561)	0
Forfeitures of dividend equivalents VALUE	0	0	0	0	0
Exercise of stock options VALUE	35	0	0	35	0
Preferred stock dividend	(752)			(752)
Net unrealized gain (loss) on investments VALUE	0	0	0	0	0
Net unrealized gain (loss) on derivatives VALUE	0	0	0	0	0
Ending Balance VALUE at Dec. 31, 2015	$ 361,450	$ 325	$ 72	$ 611,754	$ (250,701)