Leadership Changes and Restructuring Activities - Rollforward of Estimated Fair Value Liability Established for Total Severance and Other Related Costs (Details) - USD ($)		12 Months Ended
	Aug. 19, 2015	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Restructuring Cost and Reserve [Line Items]
Severance and other related expense		$ 1,482,000	$ 4,617,000
Non-cash adjustment		(1,453,000)	(2,002,000)	$ (2,995,000)
Restricted Stock Units (RSUs)
Restructuring Cost and Reserve [Line Items]
Non-cash adjustment		$ (1,453,000)	$ (2,002,000)	$ (247,000)
Accelerated vesting of restricted stock units	7,576	14,866	30,304
Restructuring Plan
Restructuring Cost and Reserve [Line Items]
Balance, January 1, 2015		$ 2,408,000
Severance and other related expense		1,554,000	$ 4,848,000
Accretion		82,000
Cash payments		(1,807,000)	(1,433,000)
Non-cash adjustment		(216,000)	(1,007,000)
Balance, September 30, 2015		$ 2,021,000	$ 2,408,000