CONSOLIDATED STATEMENTS OF CHANGES IN SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Loss	Retained Earnings	Treasury Stock	Total
Balance (As Previously Reported) at Dec. 31, 2010	$ 351	$ 268,535	$ (1,185)	$ 161,537	$ (656)	$ 428,582
Balance (in shares) (As Previously Reported) at Dec. 31, 2010	35,127,000
Increase (Decrease) in Shareholders' Equity
Cumulative restatement adjustments (in shares) | Restatement Adjustments	(1,161,000)
Balance at Dec. 31, 2011	$ 340	270,542	(1,185)	108,990	(656)	378,031
Balance (in shares) at Dec. 31, 2011	33,966,000
Increase (Decrease) in Shareholders' Equity
Cumulative restatement adjustments | Restatement Adjustments	$ (11)	2,007		(52,547)		(50,551)
Net (loss) income | As Previously Reported						63,692
Net (loss) income | Restatement Adjustments						(15,668)
Net (loss) income				48,024		48,024
Issuance of common stock upon vesting of restricted stock units	$ 4	(4)
Issuance of common stock upon vesting of restricted stock units (in shares)	377,000
Issuance of common stock in connection with the exercise of stock options	$ 3	3,557				3,560
Issuance of common stock in connection with the exercise of stock options (in shares)	239,000
Purchase and retirement of common stock	$ (1)	(1,349)				(1,350)
Purchase and retirement of common stock (in shares)	(49,000)
Stock-based compensation expense		8,256				8,256
Tax benefit associated with vesting of restricted stock units		1,268				1,268
Tax benefit on unrealized gain (loss) on SERP			439			439
Other comprehensive (loss)			(1,173)			(1,173)
Balance at Dec. 31, 2012	$ 346	282,270	(1,919)	157,014	(656)	437,055
Balance (in shares) at Dec. 31, 2012	34,533,000
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						9,490
Net (loss) income | Restatement Adjustments						(7,726)
Net (loss) income						1,764
Balance (As Previously Reported) at Mar. 31, 2013						515,632
Balance (Restatement Adjustments)						(73,594)
Balance at Mar. 31, 2013						$ 442,038
Balance (in shares) at Mar. 31, 2013						34,812,658
Balance at Dec. 31, 2012	$ 346	282,270	(1,919)	157,014	(656)	$ 437,055
Balance (in shares) at Dec. 31, 2012	34,533,000
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						23,569
Net (loss) income | Restatement Adjustments						(10,608)
Net (loss) income						12,961
Balance (As Previously Reported) at Jun. 30, 2013						533,048
Balance (Restatement Adjustments)						(76,325)
Balance at Jun. 30, 2013						$ 456,723
Balance (in shares) at Jun. 30, 2013						34,921,777
Balance at Dec. 31, 2012	$ 346	282,270	(1,919)	157,014	(656)	$ 437,055
Balance (in shares) at Dec. 31, 2012	34,533,000
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						45,228
Net (loss) income | Restatement Adjustments						(16,749)
Net (loss) income						28,479
Balance (As Previously Reported) at Sep. 30, 2013						557,100
Balance (Restatement Adjustments)						(82,374)
Balance at Sep. 30, 2013						$ 474,726
Balance (in shares) at Sep. 30, 2013						34,921,213
Balance at Dec. 31, 2012	$ 346	282,270	(1,919)	157,014	(656)	$ 437,055
Balance (in shares) at Dec. 31, 2012	34,533,000
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						63,584
Net (loss) income | Restatement Adjustments						(23,073)
Net (loss) income				40,511		40,511
Issuance of common stock upon vesting of restricted stock units	$ 3	(3)
Issuance of common stock upon vesting of restricted stock units (in shares)	348,000
Issuance of common stock in connection with the exercise of stock options	$ 2	2,435				2,437
Issuance of common stock in connection with the exercise of stock options (in shares)	205,000
Purchase and retirement of common stock		(2,374)				(2,374)
Purchase and retirement of common stock (in shares)	(69,000)
Stock-based compensation expense		9,437				9,437
Tax benefit associated with vesting of restricted stock units		3,348				3,348
Tax benefit on unrealized gain (loss) on SERP			(531)			(531)
Other comprehensive (loss)			1,430			1,430
Balance (As Previously Reported) at Dec. 31, 2013						580,220
Balance (Restatement Adjustments)						(88,907)
Balance at Dec. 31, 2013	$ 351	295,113	(1,020)	197,525	(656)	$ 491,313
Balance (in shares) at Dec. 31, 2013	35,017,000					35,017,042
Balance (As Previously Reported) at Mar. 31, 2013						$ 515,632
Balance (Restatement Adjustments)						(73,594)
Balance at Mar. 31, 2013						$ 442,038
Balance (in shares) at Mar. 31, 2013						34,812,658
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						$ 14,079
Net (loss) income						11,197
Balance (As Previously Reported) at Jun. 30, 2013						533,048
Balance (Restatement Adjustments)						(76,325)
Balance at Jun. 30, 2013						$ 456,723
Balance (in shares) at Jun. 30, 2013						34,921,777
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						$ 21,659
Net (loss) income						15,518
Balance (As Previously Reported) at Sep. 30, 2013						557,100
Balance (Restatement Adjustments)						(82,374)
Balance at Sep. 30, 2013						$ 474,726
Balance (in shares) at Sep. 30, 2013						34,921,213
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						$ 18,356
Net (loss) income						12,032
Tax benefit on unrealized gain (loss) on SERP						(531)
Balance (As Previously Reported) at Dec. 31, 2013						580,220
Balance (Restatement Adjustments)						(88,907)
Balance at Dec. 31, 2013	$ 351	295,113	(1,020)	197,525	(656)	$ 491,313
Balance (in shares) at Dec. 31, 2013	35,017,000					35,017,042
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						$ 5,997
Net (loss) income | Restatement Adjustments						(15,964)
Net (loss) income						(9,967)
Balance (As Previously Reported) at Mar. 31, 2014						590,502
Balance (Restatement Adjustments)						(104,879)
Balance at Mar. 31, 2014						$ 485,623
Balance (in shares) at Mar. 31, 2014						35,344,879
Balance (As Previously Reported) at Dec. 31, 2013						$ 580,220
Balance (Restatement Adjustments)						(88,907)
Balance at Dec. 31, 2013	$ 351	295,113	(1,020)	197,525	(656)	$ 491,313
Balance (in shares) at Dec. 31, 2013	35,017,000					35,017,042
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						$ 18,616
Net (loss) income | Restatement Adjustments						(25,352)
Net (loss) income						(6,736)
Balance (As Previously Reported) at Jun. 30, 2014						606,043
Balance (Restatement Adjustments)						(113,993)
Balance at Jun. 30, 2014						$ 492,050
Balance (in shares) at Jun. 30, 2014						35,385,848
Balance (As Previously Reported) at Dec. 31, 2013						$ 580,220
Balance (Restatement Adjustments)						(88,907)
Balance at Dec. 31, 2013	$ 351	295,113	(1,020)	197,525	(656)	$ 491,313
Balance (in shares) at Dec. 31, 2013	35,017,000					35,017,042
Increase (Decrease) in Shareholders' Equity
Net (loss) income						$ (15,537)
Balance at Sep. 30, 2014						$ 485,263
Balance (in shares) at Sep. 30, 2014						35,396,374
Balance (As Previously Reported) at Dec. 31, 2013						$ 580,220
Balance (Restatement Adjustments)						(88,907)
Balance at Dec. 31, 2013	$ 351	295,113	(1,020)	197,525	(656)	$ 491,313
Balance (in shares) at Dec. 31, 2013	35,017,000					35,017,042
Increase (Decrease) in Shareholders' Equity
Net (loss) income				(18,966)		$ (18,966)
Issuance of common stock upon vesting of restricted stock units	$ 4	(4)
Issuance of common stock upon vesting of restricted stock units (in shares)	377,000
Issuance of common stock in connection with the exercise of stock options		87				87
Issuance of common stock in connection with the exercise of stock options (in shares)	5,000
Stock-based compensation expense		9,773				9,773
Tax benefit associated with vesting of restricted stock units		2,197				2,197
Tax benefit on unrealized gain (loss) on SERP			525			525
Other comprehensive (loss)			(1,393)			(1,393)
Balance at Dec. 31, 2014	$ 355	307,166	(1,888)	178,559	(656)	$ 483,536
Balance (in shares) at Dec. 31, 2014	35,399,000					35,399,476
Balance (As Previously Reported) at Mar. 31, 2014						$ 590,502
Balance (Restatement Adjustments)						(104,879)
Balance at Mar. 31, 2014						$ 485,623
Balance (in shares) at Mar. 31, 2014						35,344,879
Increase (Decrease) in Shareholders' Equity
Net (loss) income | As Previously Reported						$ 12,619
Net (loss) income						3,231
Balance (As Previously Reported) at Jun. 30, 2014						606,043
Balance (Restatement Adjustments)						(113,993)
Balance at Jun. 30, 2014						$ 492,050
Balance (in shares) at Jun. 30, 2014						35,385,848
Increase (Decrease) in Shareholders' Equity
Net (loss) income						$ (8,801)
Balance at Sep. 30, 2014						$ 485,263
Balance (in shares) at Sep. 30, 2014						35,396,374
Increase (Decrease) in Shareholders' Equity
Net (loss) income						$ (3,429)
Tax benefit on unrealized gain (loss) on SERP						(525)
Balance at Dec. 31, 2014	$ 355	$ 307,166	$ (1,888)	$ 178,559	$ (656)	$ 483,536
Balance (in shares) at Dec. 31, 2014	35,399,000					35,399,476