CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 9,887	$ 9,288	$ 18,309	$ 16,170
Pension and post-retirement obligations:
Amortization of actuarial (gains) losses and prior service credit to earnings, net of tax	(136)	474	(272)	948
Derivative instruments designated as cash flow hedges:
Change in fair value of derivatives, net of tax		163		131
Reclassification of realized loss to earnings, net of tax	303	556	711	2,846
Comprehensive income	10,054	10,481	18,748	20,095
Less: comprehensive income attributable to noncontrolling interest	80	94	178	193
Total comprehensive income attributable to common shareholders	$ 9,974	$ 10,387	$ 18,570	$ 19,902