Pension, Postretirement and Postemployment Benefits (Details) (Pension Benefits, USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Benefits
Change in benefit obligation:
Benefit obligation at beginning of year	$ 26,193,000	$ 29,205,000
Interest cost	1,219,000	1,078,000	1,116,000
Actuarial loss (gain)	5,974,000	(3,360,000)
Benefit payments	(791,000)	(730,000)
Benefit obligation at end of year	32,595,000	26,193,000	29,205,000
Change in plan assets:
Defined Benefit Plan, Fair Value of Plan Assets, Beginning Balance	21,384,000	18,780,000
Actual (loss) return on plan assets	1,690,000	2,736,000
Employer contributions	1,251,000	598,000
Benefit payments	(791,000)	(730,000)
Defined Benefit Plan, Fair Value of Plan Assets, Ending Balance	23,534,000	21,384,000	18,780,000
Funded status:
Underfunded status at end of year	(9,061,000)	(4,809,000)
Amounts recognized in consolidated balance sheets:
Other long-term liabilities	(9,061,000)	(4,809,000)
Components of net periodic benefit cost (recognized in our consolidated statements of income (loss)):
Interest cost	1,219,000	1,078,000	1,116,000
Expected return on plan assets	(1,401,000)	(1,210,000)	(1,086,000)
Recognized net actuarial loss	485,000	1,123,000	1,034,000
Defined Benefit Plan, Net Periodic Benefit Cost, Total	303,000	991,000	1,064,000
Weighted-average assumptions:
Weighted-average discount rate (as a percent)	4.00%	4.75%	3.75%
Expected long-term rate of return on plan assets (as a percent)	6.00%	6.50%	6.50%
Net actuarial loss included in accumulated other comprehensive income (loss)	(11,800,000)	(6,600,000)	(12,700,000)
Amount expected to recognize as a components of net periodic benefit costs	$ 1,100,000