Employee Benefit Plans - Awards Activity (Details) - $ / shares		12 Months Ended
		Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014
Stock Options [Member]
Summary of options issued and outstanding
Balance at the beginning of the period (in shares)		2,360,340
Options granted (in shares)		0		0
Options exercised (in shares)		(768,212)
Options forfeited/expired (in shares)		(421,535)
Balance at the end of the period (in shares)		1,170,593		2,360,340
Weighted Average Exercise Price
Balance at the beginning of the period (in dollars per share)		$ 21.73
Options granted (in dollars per share)		0.00
Options exercised (in dollars per share)		24.64
Options forfeited (in dollars per share)		25.50
Balance at the end of the period (in dollars per share)		$ 18.43		$ 21.73
Weighted Average Grant Date Fair Value (in dollars per share)	[1]				$ 10.35
Number of Exercisable Options (in shares)		1,145,356		2,275,096
Performance Stock Options [Member]
Summary of options issued and outstanding
Balance at the beginning of the period (in shares)		239,537
Options granted (in shares)		0		20,000.00	0
Options exercised (in shares)		(5,533)
Options forfeited/expired (in shares)		(12,595)
Balance at the end of the period (in shares)		221,409		239,537
Weighted Average Exercise Price
Balance at the beginning of the period (in dollars per share)		$ 17.92
Options granted (in dollars per share)		0.00
Options exercised (in dollars per share)		19.08
Options forfeited (in dollars per share)		19.24
Balance at the end of the period (in dollars per share)		$ 17.89		$ 17.92
Number of Exercisable Options (in shares)		221,409		166,897
Restricted Stock Awards [Member]
Restricted Stock Award and Restricted Stock Unit Activity
Nonvested at the beginning of the period (in shares)		62,145
Granted (in shares)		58,858
Vested (in shares)		(62,145)
Forfeited (in shares)		0
Nonvested at the end of the period (in shares)		58,858		62,145
Weighted Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)		$ 25.67
Granted (in dollars per share)		25.57
Vested (in dollars per share)		25.67
Forfeited (in dollars per share)		0.00
Nonvested at the end of the period (in dollars per share)		$ 25.57		$ 25.67
Restricted Stock Units [Member]
Restricted Stock Award and Restricted Stock Unit Activity
Nonvested at the beginning of the period (in shares)		689,281
Granted (in shares)		377,661
Vested (in shares)		(114,701)
Forfeited (in shares)		(6,732)
Nonvested at the end of the period (in shares)		945,509		689,281
Weighted Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)		$ 23.23
Granted (in dollars per share)		24.51
Vested (in dollars per share)		20.88
Forfeited (in dollars per share)		24.38
Nonvested at the end of the period (in dollars per share)		$ 24.01		$ 23.23
Performance Restricted Stock Units [Member]
Restricted Stock Award and Restricted Stock Unit Activity
Nonvested at the beginning of the period (in shares)		408,260
Granted (in shares)		270,612
Vested (in shares)		(69,437)
Forfeited (in shares)		0
Nonvested at the end of the period (in shares)		609,435	[2]	408,260
Weighted Average Grant-Date Fair Value
Nonvested at the beginning of the period (in dollars per share)		$ 27.32
Granted (in dollars per share)		25.62
Vested (in dollars per share)		29.43
Forfeited (in dollars per share)		0.00
Nonvested at the end of the period (in dollars per share)		$ 26.22	[2]	$ 27.32
Excluded due to nonperformance (in shares)		355,353

[1] No options were granted in 2016 and 2015.

[2] Excludes 355,353 performance restricted stock units that have met performance hurdles and will be eligible for vesting after December 31, 2016.