Organization and Summary of Significant Accounting Policies - Leases (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018	Jun. 30, 2018	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Package of practical expedients	true
Assets
Other current assets	$ 14,888		$ 12,961	$ 18,731
Total current assets	274,220		320,130	325,900
Property, plant and equipment, net	85,210		81,421	89,489
Other intangible assets, net	15,770		15,258	15,478
Deferred income taxes	66,682		65,065	65,635
Operating lease right-of-use assets	104,632		103,378
Other assets	7,589		8,304	7,766
Total assets	780,835		792,298	703,010
Current liabilities:
Current portion of long-term debt	8,648		7,964	8,583
Accrued expenses and other current liabilities	53,107		50,431	51,783
Current portion of operating lease liabilities	30,592		31,479
Total current liabilities	181,924		200,782	171,274
Long-term debt, less current portion	489,662		489,597	502,090
Operating lease liabilities	85,046		83,662
Other liabilities	46,033		38,620	51,570
Total liabilities	802,665		812,661	724,934
Shareholders' deficit:
Retained Earnings (Accumulated Deficit)	(356,378)		(359,462)	(361,023)
Total shareholders' deficit	(21,830)	$ (30,605)	(20,363)	(21,924)	$ (35,300)	$ (53,575)	$ (28,810)	$ (28,051)
Total liabilities and shareholders' deficit	$ 780,835		792,298	$ 703,010
ASU 2016-02 | Restatement Adjustments
Assets
Other current assets			(5,770)
Total current assets			(5,770)
Property, plant and equipment, net			(8,068)
Other intangible assets, net			(220)
Deferred income taxes			(570)
Operating lease right-of-use assets			103,378
Other assets			538
Total assets			89,288
Current liabilities:
Current portion of long-term debt			(619)
Accrued expenses and other current liabilities			(1,352)
Current portion of operating lease liabilities			31,479
Total current liabilities			29,508
Long-term debt, less current portion			(12,493)
Operating lease liabilities			83,662
Other liabilities			(12,950)
Total liabilities			87,727
Shareholders' deficit:
Retained Earnings (Accumulated Deficit)			1,561
Total shareholders' deficit			1,561
Total liabilities and shareholders' deficit			$ 89,288