Employee Benefit Plans - Narrative (Details) (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Estimated future benefit payments expected to be paid in 2014	$ 21,600,000
Estimated future benefit payments expected to be paid in 2015	22,600,000
Estimated future benefit payments expected to be paid in 2016	23,600,000
Estimated future benefit payments expected to be paid in 2017	25,000,000
Estimated future benefit payments expected to be paid in 2018	26,600,000
Total estimated future benefit payments expected to be paid for the five years ending 2023	156,400,000
Percentage of total contributions made to multi-employer plans	5.00%
Number of multi-employer pension plans	4
Number of multi-employer plans deemed significant	2
CWA/ITU
Defined Benefit Plan Disclosure [Line Items]
Multi-employer plan withdrawal liability	4,800,000
GCIU
Defined Benefit Plan Disclosure [Line Items]
Multi-employer plan withdrawal liability	30,700,000
SERP
Defined Benefit Plan Disclosure [Line Items]
Amortization of actuarial gain (loss)	400,000	300,000	1,300,000
Current year actuarial gain (loss)	700,000	2,300,000	1,600,000
Settlement charge	1,100,000
Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Amortization of actuarial gain (loss)	4,192,000	4,246,000	2,982,000
Current year actuarial gain (loss)	52,063,000	(30,761,000)	(29,350,000)
Minimum
Defined Benefit Plan Disclosure [Line Items]
Period of consideration for historical plan asset rate of return	10 years
Historical period considered	10 years
Maximum
Defined Benefit Plan Disclosure [Line Items]
Period of consideration for historical plan asset rate of return	15 years
Historical period considered	15 years
Fixed-income securities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations range	70.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Target plan asset allocations range	30.00%
Scenario, Forecast [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected amortization of actuarial loss from accumulated other comprehensive loss into net periodic benefit costs	2,900,000
Scenario, Forecast [Member] | SERP
Defined Benefit Plan Disclosure [Line Items]
Expected amortization of actuarial loss from accumulated other comprehensive loss into net periodic benefit costs	300,000
Expected contributions to benefit plans	800,000
Scenario, Forecast [Member] | Defined Benefit Plans
Defined Benefit Plan Disclosure [Line Items]
Expected contributions to benefit plans	$ 100,000