Consolidated Statements of Comprehensive Income - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income	$ 39,301,000	$ 48,061,000	$ 18,288,000
Other comprehensive income (loss):
Adjustment to pension liability	5,783,000	(17,053,000)	16,001,000
Income tax expense (benefit)	2,255,000	(6,650,000)	6,240,000
Other comprehensive income (loss)	3,528,000	(10,403,000)	9,761,000
Comprehensive income	$ 42,829,000	$ 37,658,000	$ 28,049,000