CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY (Parenthetical) (USD $) In Thousands, except Per Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Minimum pension liability adjustment, tax benefit (loss)	$ 10,853	$ (8,397)	$ 2,847
Unrealized benefit on interest rate swaps, tax loss	380	1,008	3,505
Cash dividend per share	$ 0.56	$ 0.56	$ 0.53
Accumulated Other Comprehensive Income (Loss) [Member]
Minimum pension liability adjustment, tax benefit (loss)	10,853	(8,397)	2,847
Unrealized benefit on interest rate swaps, tax loss	$ 380	$ 1,008	$ 3,505
Retained Earnings [Member]
Cash dividend per share	$ 0.56	$ 0.56	$ 0.53