Employee Benefit Plans - Narrative (Details)	1 Months Ended		12 Months Ended					132 Months Ended
	Jan. 31, 2016 USD ($) $ / shares shares	May. 31, 2012 shares	Dec. 31, 2015 USD ($) long-term_incentive_stock-based_plan $ / shares shares	Dec. 31, 2014 USD ($) $ / shares shares	Dec. 31, 2013 USD ($) $ / shares shares	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2015 USD ($) $ / shares shares	Jan. 31, 2015 USD ($)
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of stock plans | long-term_incentive_stock-based_plan			1
Granted (in shares) | shares			501,076	139,455	168,468
Grants in period (in shares) | shares			295,693	73,609	89,329
Grant date fair value (in dollars per share) | $ / shares			$ 25.06	$ 26.79	$ 27.50			$ 25.06
Stock option grants (in shares) | shares								0
Options exercised in period (in shares) | shares					52,800
Options weighted average exercise price (in dollars per share) | $ / shares					$ 13.91
Intrinsic value of options exercised					$ 500,000
Deferred compensation arrangement with individual award vesting period						3 years	5 years
Long-term incentive cash awards granted			$ 0	$ 8,900,000	8,400,000			$ 0
Compensation expense				7,200,000	9,100,000
Deferred compensation cash-based arrangement, liability			100,000	12,800,000				$ 100,000
Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense				3,600,000	5,300,000
Deferred compensation cash-based arrangement, liability				7,900,000
Adjustment [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense			(3,700,000)
Adjustment [Member] | Executive Officer [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense			$ (2,100,000)
Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term incentive cash awards granted	$ 0
Long-term incentive cash awards paid	$ 0
E S P P [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance (in shares) | shares			1,500,000					1,500,000
Shares available for issuance (in shares) | shares			900,000					900,000
Period common stock may be purchased through payroll deductions			4 months
Percentage of share of non-vested stock considered as call option			85.00%					85.00%
Percentage of share of non-vested stock considered as put option			15.00%
Allocated share-based compensation expense			$ 1,100,000	1,000,000	800,000
2005 Incentive Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares) | shares			6,000,000					6,000,000
Additional shares authorized (in shares) | shares		4,300,000
Awards granted vesting percentage						33.00%	20.00%
Vesting period						3 years	5 years
2005 Incentive Plan [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted vesting percentage	33.00%
Granted (in shares) | shares	1,143,062
Market value per share (in dollars per share) | $ / shares	$ 5.26
Future compensation expense	$ 6,000,000
Vesting period	3 years
Grants in period (in shares) | shares	1,143,062
2005 Incentive Plan [Member] | Maximum Shares As Incentive Options Member
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares available for issuance (in shares) | shares			2,000,000					2,000,000
Restricted Stock Units and Restricted Stock Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost			$ 5,500,000	5,000,000	6,600,000
Forfeiture on restricted stock percentage			6.00%
Forfeiture on restricted stock period			5 years
Future compensation expense			$ 6,500,000					$ 6,500,000
Weighted average vesting period			1 year 9 months 18 days
Performance Shares [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Awards granted vesting percentage			100.00%
Compensation cost			$ 200,000	5,400,000	2,200,000
Vesting period			3 years
Recorded liability			$ 700,000	7,900,000				700,000
Long-term incentive cash awards paid									$ 4,500,000
Performance Shares [Member] | Maximum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award percentage			200.00%
Performance Shares [Member] | Minimum [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Award percentage			0.00%
Performance Shares [Member] | Subsequent Event [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-term incentive cash awards paid	$ 200,000
Modified Liability Performance Share [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation expense in excess of fair value recorded in equity			$ 2,900,000
Long-Term Incentive Cash Plans [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Minimum percentage of average price during measurement period (less than)			75.00%
Long-term incentive cash awards paid			$ 8,900,000	$ 9,200,000	$ 7,100,000			$ 8,900,000
401K Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Employer matching contribution (as a percent)				75.00%	50.00%
Matching contribution percent of employees' salary (up to)				5.00%	5.00%
Cost of plan			$ 2,800,000	$ 2,200,000	$ 1,700,000