GUARANTOR - Condensed Shareholder's Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				$ 298,393				$ 269,494	$ 298,393	$ 269,494	$ 253,688
Net income (loss)	10,850	6,473	8,137	1,363	9,507	6,875	9,893	(251)	26,823	26,024	11,268
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									5,232	4,270	5,754
Issuance of common stock related to an incentive plan VALUE									0	0	0
Common stock repurchase VALUE									0	0	0
Purchase of vested employee restricted stock units									(1,514)	(1,640)	(1,367)
Purchase of vested employee restricted stock units SHARES									(142,000)	(186,000)	(199,000)
Forfeitures of dividend equivalents VALUE									5	0	16
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0		0
Exercise of stock options SHARES									57,500
Exercise of stock options VALUE									82	245	135
Ending Balance VALUE	329,021				298,393				329,021	298,393	269,494
Common Class A [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				313				312	313	312	310
Opening Balance SHARES				31,308,194				31,226,047	31,308,194	31,226,047	31,044,001
Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures									638,102	96,560	280,072
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									7	1	3
Stock Issued During Period Shares Employee Stock Purchase Plans									0	0	0
Issuance of common stock related to an incentive plan VALUE									0	0	0
Common stock repurchase SHARES										0	0
Common stock repurchase VALUE									0	0	0
Purchase of vested employee restricted stock units									(1)	(2)	(2)
Purchase of vested employee restricted stock units SHARES									(141,502)	(186,038)	(199,376)
Forfeitures of dividend equivalents VALUE									0	0	0
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0
Exercise of stock options SHARES									57,500	171,625	101,350
Exercise of stock options VALUE									0	2	1
Ending Balance SHARES	31,862,294				31,308,194				31,862,294	31,308,194	31,226,047
Ending Balance VALUE	319				313				319	313	312
Common Class B [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				72				72	72	72	72
Opening Balance SHARES				7,197,532				7,197,532	7,197,532	7,197,532	7,197,532
Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures									0	0	0
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									0	0	0
Stock Issued During Period Shares Employee Stock Purchase Plans									0	0	0
Issuance of common stock related to an incentive plan VALUE									0	0	0
Common stock repurchase SHARES										0	0
Common stock repurchase VALUE									0	0	0
Purchase of vested employee restricted stock units									0	0	0
Purchase of vested employee restricted stock units SHARES									0	0	0
Forfeitures of dividend equivalents VALUE									0	0	0
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options SHARES									0	0	0
Exercise of stock options VALUE									0	0	0
Ending Balance SHARES	7,197,532				7,197,532				7,197,532	7,197,532	7,197,532
Ending Balance VALUE	72				72				72	72	72
Additional Paid In Capital [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				604,721				601,847	604,721	601,847	597,327
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									5,225	4,269	5,751
Issuance of common stock related to an incentive plan VALUE									0	0	0
Common stock repurchase VALUE									0	0	0
Purchase of vested employee restricted stock units									(1,513)	(1,638)	(1,365)
Forfeitures of dividend equivalents VALUE									0	0	0
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options VALUE									82	243	134
Ending Balance VALUE	608,515				604,721				608,515	604,721	601,847
Retained Earnings [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				(306,713)				(332,737)	(306,713)	(332,737)	(344,021)
Net income (loss)									26,823	26,024	11,268
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									0	0	0
Issuance of common stock related to an incentive plan VALUE									0	0	0
Common stock repurchase VALUE									0	0	0
Purchase of vested employee restricted stock units									0	0	0
Forfeitures of dividend equivalents VALUE									5	0	16
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options VALUE									0	0	0
Ending Balance VALUE	(279,885)				(306,713)				(279,885)	(306,713)	(332,737)
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				298,393				269,494	298,393	269,494	253,688
Net income (loss)									26,823	26,024	11,268
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									5,232	4,270	5,754
Purchase of vested employee restricted stock units									(1,514)	(1,640)	(1,367)
Forfeitures of dividend equivalents VALUE									5	0	16
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options SHARES									57,500
Exercise of stock options VALUE									82	245	135
Ending Balance VALUE	329,021				298,393				329,021	298,393	269,494
Parent Company [Member] | Common Class A [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				313				312	313	312	310
Opening Balance SHARES				31,308,194				31,226,047	31,308,194	31,226,047	31,044,001
Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures									638,102	96,560	280,072
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									7	1	3
Purchase of vested employee restricted stock units									(1)	(2)	(2)
Purchase of vested employee restricted stock units SHARES									(141,502)	(186,038)	(199,376)
Forfeitures of dividend equivalents VALUE									0	0	0
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options SHARES									0	171,625	101,350
Exercise of stock options VALUE									0	2	1
Ending Balance SHARES	31,862,294				31,308,194				31,862,294	31,308,194	31,226,047
Ending Balance VALUE	319				313				319	313	312
Parent Company [Member] | Common Class B [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				72				72	72	72	72
Opening Balance SHARES				7,197,532				7,197,532	7,197,532	7,197,532	7,197,532
Stock Issued During Period Shares Restricted Stock Award Net Of Forfeitures									0	0	0
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									0	0	0
Purchase of vested employee restricted stock units									0	0	0
Purchase of vested employee restricted stock units SHARES									0	0	0
Forfeitures of dividend equivalents VALUE									0	0	0
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options SHARES										0	0
Exercise of stock options VALUE									0	0	0
Ending Balance SHARES	7,197,532				7,197,532				7,197,532	7,197,532	7,197,532
Ending Balance VALUE	72				72				72	72	72
Parent Company [Member] | Additional Paid In Capital [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				604,721				601,847	604,721	601,847	597,327
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									5,225	4,269	5,751
Purchase of vested employee restricted stock units									(1,513)	(1,638)	(1,365)
Forfeitures of dividend equivalents VALUE									0	0	0
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options VALUE									82	243	134
Ending Balance VALUE	608,515				604,721				608,515	604,721	601,847
Parent Company [Member] | Retained Earnings [Member]
Condensed Financial Statements, Captions [Line Items]
Opening Balance VALUE				(306,713)				(332,737)	(306,713)	(332,737)	(344,021)
Net income (loss)									26,823	26,024	11,268
Stock Issued During Period Value Restricted Stock Award Net Of Forfeitures									0	0	0
Purchase of vested employee restricted stock units									0	0	0
Forfeitures of dividend equivalents VALUE									5	0	16
Realization of tax benefit for dividend equivalent payments VALUE										0	0
Net unrealized gain (loss) on derivatives VALUE									0	0	0
Exercise of stock options VALUE									0	0	0
Ending Balance VALUE	$ (279,885)				$ (306,713)				$ (279,885)	$ (306,713)	$ (332,737)