Indebtedness (Schedule of Indebtedness) (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
8.25% senior notes, face amount of $510.0 million, interest rate of 8.25% payable semi-annually, in arrears on February 15 and August 15 of each year, maturity date February 15, 2018	$ 497,355,000	$ 494,911,000
Senior Credit Facility, interest rate based on base rate or LIBOR plus a floating spread, maturity date October 31, 2016	130,000,000	195,000,000
Total indebtedness	627,355,000	689,911,000
Current portion of indebtedness	0	0
Noncurrent portion of indebtedness	627,355,000	689,911,000
8.25% Senior Notes [Member]
Noncurrent portion of indebtedness	497,355,000	494,911,000
Senior Notes, face amount	510,000,000
Senior Notes, stated percentage	8.25%
Maturity date	Feb. 15, 2018
Parent Company [Member]
Noncurrent portion of indebtedness	627,355,000	689,911,000
Revolving Credit Facility [Member]
Noncurrent portion of indebtedness	$ 130,000,000	$ 195,000,000
Maturity date	Oct. 31, 2016